(2021) 28:28
Zhuang et al. J Biomed Sci
https://doi.org/10.1186/s12929-021-00725-7

Open Access

REVIEW

Mesenchymal stem/stromal cell‑based
therapy: mechanism, systemic safety
and biodistribution for precision clinicalapplications
Wei‑Zhan Zhuang1,2,3†, Yi‑Heng Lin1,4,5†, Long‑Jyun Su6, Meng‑Shiue Wu7, Han‑Yin Jeng1,3,
Huan‑Cheng Chang6,8, Yen‑Hua Huang1,2,3,9,10,11,12* and Thai‑Yen Ling7,13*

Abstract
Mesenchymal stem/stromal cells (MSCs) are a promising resource for cell-based therapy because of their high immu‑
nomodulation ability, tropism towards inflamed and injured tissues, and their easy access and isolation. Currently,
there are more than 1200 registered MSC clinical trials globally. However, a lack of standardized methods to character‑ize cell safety, efficacy, and biodistribution dramatically hinders the progress of MSC utility in clinical practice. In thisreview, we summarize the current state of MSC-based cell therapy, focusing on the systemic safety and biodistribu‑
tion of MSCs. MSC-associated risks of tumor initiation and promotion and the underlying mechanisms of these risks
are discussed. In addition, MSC biodistribution methodology and the pharmacokinetics and pharmacodynamics ofcell therapies are addressed. Better understanding of the systemic safety and biodistribution of MSCs will facilitate
future clinical applications of precision medicine using stem cells.
Keywords: Mesenchymal stem/stromal cell, Cell therapy, Systemic safety, biodistribution, Single cell imaging
Introduction
Cell therapy has become one of the most important
emerging medical treatments in the world. Treatments
utilizing stem cells, induced pluripotent stem cells(iPSCs), somatic cells, and immune cells are well documented [1]. Many cell therapy products have alreadyreceived global market approval. Among them, the mesenchymal/stromal stem cells (MSCs) present a promising
tool for the treatment of various diseases.
*Correspondence: rita1204@tmu.edu.tw; tyling@ntu.edu.tw†
Wei-Zhan Zhuang and Yi-Heng Lin contributed equally to this work
1
Department of Biochemistry and Molecular Cell Biology, Schoolof Medicine, College of Medicine, Taipei Medical University, 250 Wuxing
Street, Taipei 11031, Taiwan
7
Department and Graduate Institute of Pharmacology, Collegeof Medicine, National Taiwan University, Taipei 10617, Taiwan
Full list of author information is available at the end of the article

MSCs were first isolated and described by Friedensteinand his colleagues as adherent and highly replicative cells
that can differentiate into mesodermal lineages including
osteoblasts, chondrocytes, adipocytes, and hematopoietic stroma [2]. Since then, these cells have gained attention in the field of cell therapy for their tropism towards
injured/inflamed tissues, their immunomodulatory
capabilities [3], and their relative ease of isolation andexpansion [4]. MSCs can be isolated from many sources,
including bone marrow [5], umbilical cord [6], adipose
tissue [7], cord blood [6], placenta [8], dental pulp [9],endometrium [10], amniotic fluid [11], skeletal muscle
tissue [12], lung tissue [13], liver tissue [7, 12] and dermal tissue [12], and many of these cells have been usedin clinical studies (Fig. 1a). The characteristics of MSCs
make them attractive as cellular therapeutic agents forregenerative medicine and immune-related diseases.

© The Author(s) 2021. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which
permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to theoriginal author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images orother third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line
to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory
regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of thislicence, visit http://​creat​iveco​mmons.​org/​licen​ses/​by/4.​0/. The Creative Commons Public Domain Dedication waiver (http://​creat​iveco​
mmons.​org/​publi​cdoma​in/​zero/1.​0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Zhuang et al. J Biomed Sci(2021) 28:28

Page 2 of 38(See figure on next page.)
Fig. 1 MSC sources and clinical indications in clinical studies. As of October 11, 2020, 1,242 registered studies were identified on clinicaltrials.gov
by searching keywords “mesenchymal stem cell” or “mesenchymal stromal cell” (Additional file 1). After excluding studies with no longer available/suspended/ temporarily not available/ terminated/ unknown/ withdrawn status, unknown phase information, and studies that did not use MSCs intheir intervention arm, 639 studies remained. Nine of these 639 studies investigated MSCs from two tissue origins, generating a total of 648 studies
for analysis. a Tissue origins of MSCs in clinical studies, b number of MSC-related clinical studies by medical specialty, and c the top 20 disease
indications of MSC-related clinical studies

The first clinical trial of MSCs was reported in 1995 inpatients with hematologic malignancies. Lazarus et al.
demonstrated that ex vivo expansion and subsequentinfusion of human bone marrow-derived stromal progenitor cells (BMMSCs) in patients caused no severe adverse
effects [14]. Subsequently, treatment with BMMSCs wasshown to provide clinical improvement in the rare skeletal disease osteogenesis imperfecta [15]. Furthermore,
many clinical trials have examined the feasibility andefficacy of MSCs for the treatment of various conditions,
including acute organ failure [16–18], graft-versus-hostdisease (GVHD) [19–21], ischemic heart disease [22, 23],
cardiovascular disease [24, 25], liver cirrhosis [26], diabetes [27, 28], spinal cord injury [29–31], and bone/cartilage injury [32–37] (Table 1). According to the National
Institutes of Health (http://​www.​clini​caltr​ial.​gov/), thenumber of registered MSC-based clinical trials was over
1,200 as of October 11, 2020, of which approximately 600
had defined phase and status (Fig. 1b, c, Additional file 1
and Additional file 2). Most of the studies to date arephase 1 and phase 2 trials which evaluate safety and feasibility, and evidence of therapeutic efficacy is still lacking (Fig. 1). The most common indications of MSC-based
cellular therapy include osteoarthritis, ischemic heartdisease, graft-versus-host disease, spinal cord injury, andmultiple sclerosis (Fig. 1c). In addition, since the elevation of coronavirus disease-19 (COVID-19) outbreakto pandemic status on March 11, 2020 [38], numerous
MSC-based studies have been registered, and COVID19 related pneumonia and acute respiratory distress syndrome (ARDS) has risen as the second most common
indication as of October 11, 2020 (Fig. 1c). The rapid
global response and increase of COVID-19 related MSC
trials highlighted the promise of MSCs in treatment ofinflammatory and immune diseases.
Although studies on MSCs are well-documented, MSCbased cellular products still have not been approved by
the US Food and Drug Administration. The lack of consistent and standardized methods for characterizing thesafety and efficacy of MSC products is a major concern,
which dramatically slows the progress of MSC therapy
towards clinical use. The safety of cellular products isalways the first priority. Although some MSCs have beenshown to be safe for clinical use in a previous meta-analysis, whether this conclusion can be extended to MSCs

from other tissue origins or different culture conditions
is still uncertain (Fig. 1a) [39]. The risk associated with
MSC products centers around their capability to initiate
and promote tumors. These risks, as well as the biodistribution of systemically administered cells must be better clarified before the widespread use of MSCs in clinicalpractice. In this review article, we focus on the effects of
MSCs on tumor promotion and suppression, and discuss
methods to study their biodistribution.
MSC‑based mechanisms of action

Several possible mechanisms by which MSCs exert theirbeneficial effects have been proposed. Early studies
reported that MSCs could migrate to sites of injury andthen differentiate into functional cells [40], or that they
could fuse with compromised cells to regenerate damaged tissues [41, 42]. More recent studies have demonstrated that paracrine factors [43, 44], mitochondrialtransfer [45], and extracellular vesicle secretion [46] haveimportant roles in mediating the effects of MSCs.
Paracrine effects

MSCs secrete paracrine factors, including cytokines,
chemokines, growth factors, and miRNAs. MSC transplantation or administration of isolated secreted factors
enables MSC paracrine factors to get to injured tissues,
to help restore a healthy microenvironment to promote
tissue repair [47] (Table 2). MSC paracrine factors play
important roles in immunomodulation [48, 49], tissue
regeneration and healing [50, 51], anti-fibrosis [52, 53],
anti-apoptosis [54], and angiogenesis [55]. As such, manystudies have focused on altering culture conditions inorder to steer the secretome of MSCs towards therapeutic agents. Alterations have included using MSCs fromdifferent types of tissue [56, 57], oxygen concentration[58], growth factor incubation or cytokine pretreatment[59], passage number [60–62], three-dimensional spheroid culturing [63], and mechanical strain [64].
The capability of MSCs for immunomodulation has
made them a useful treatment approach for inflammatory
disorders such as multiple sclerosis [65], Crohn’s disease[66], GVHD [67], systemic lupus erythematosus [67],and type I diabetes [68]. Immunomodulation is dependent on crosstalk between MSCs and the immune microenvironment of the target tissue. In an inflammatory

Zhuang et al. J Biomed Sci(2021) 28:28

Page 3 of 38

Zhuang et al. J Biomed Sci(2021) 28:28

Page 4 of 38

Table 1 Summary of MSC-based clinical/preclinical trials
Indication

Cell source

Model

Acute organ failure

Bone marrow, Bone Rat [17, 18]

Quantification modality In vivo distribution
Histology/RT-PCR

More exogenous human MSCs localized to injured
tissuesPCR

MSC DNA detected in lymph nodes

Graft-versus-host disease (GvHD) Bone marrow

Patients [19]Ischemic disease

Bone marrow

Swine [22, 23] Histology/qPCR

DAPI staining confirmed rapid cell loss after trans‑
plantation

Lung cancer

Umbilical cord

Mouse [252]

PET-CT

MSCs remained in the lungs up to 1 week after
injection

Liver cirrhosis

Bone marrow

Patients [26]Planar whole-bodyacquisitions/SPECT

MSCs accumulated in the lung first, MSCs in theliver increased from 0.0%–2.8% to 13.0%–17.4% in
10 days

Diabetes

Bone marrow

Rat [28]

Histology/qPCR

MSCs detected in the diabetic kidneys at 24 and 48 h
after cell infusion. Cell engraftment also observedin spleen and thymus at 24 h

Spinal cord injury

Bone marrow

Rat [299]

CT/MRI

After transplantation of BMMSCs, the hypersignal
emerged in spinal cord in T1WI starting at day 7
that was focused at the injection site, which thenincreased and extended until day 14

Cartilage/bone injury

AdiposeRabbit [37]MRI

Representative tibial joint, regenerated meniscus andjoint surface of tibia at 6 and 12 weeks after surgery

BM bone marrow, MSCs mesenchymal stem/stromal cells, PCR polymerase chain reaction, PET positron emission tomography, SPECT single-photon emission
computed tomography, MRI magnetic resonance imaging, CT computed tomography

Table 2 MSC secreted factors involved in tumor promotion
Factors involved in tumor promotion
Cytokines

IL6, TGF-β1, IL-8

[125, 132, 133, 139, 147, 150, 159, 162, 165]

Chemokines

SDF-1, CXCL1, CCL2, CCL5

[123, 124, 136, 142–144, 150, 160, 162]

Angiogenic factors

VEGF, Ang-1, PDGF, IGF[148, 162]

Growth factor

NRG1

[135]

Other factors

periostin, PAI-1, Sema-7A[134, 162]

microRNAs

miR-21-5p, miR-410, MiR-142-3p, miR-23b[126, 136, 145, 158]

microenvironment, proinflammatory cytokines, including IL-1β, IL-6, IL-23, IFN-γ, and TNF-α, can stimulate
MSCs to secrete anti-inflammatory factors such as TNFα
stimulated gene (TSG)-6 [69], nitric oxide (NO) [70],IL-10 [71], galectins [72], prostaglandin E2 (PGE2) [73],and transforming growth factor (TGF)-β [3, 71]. Upon
exposure to these MSC-secreted anti-inflammatory signals, nuclear factor (NF)-κB activity and consequent
inflammatory cytokine expression in macrophages, dendritic cells, and T cells are inhibited, and immune cells
will express higher levels of anti-inflammatory cytokine
IL-10 as a result [3, 74]. The MSC paracrine factors alsointeract with other immune cells and have been reported
to skew macrophage polarization towards the M2 phenotype, which downregulates both innate and adaptive
immune responses [75]. Regulatory T cells (Treg) werealso reported to stimulate MSCs to secrete indoleamine
2,3-dioxygenase (IDO), thereby augmenting the Treg
response and attenuating acute liver injury [3, 76].

In addition to their immunomodulation ability, MSCs
are able to secrete factors that can promote cell proliferation, increase angiogenesis, and reduce cell apoptosis.
For example, MSCs can secrete growth and angiogenesis-promoting factors such as basic fibroblast growth
factor (bFGF) [77], insulin-like growth factor (IGF) [78],TGF-β [3, 55], stromal cell-derived factor (SDF)-1α [79],secreted frizzled-related protein-1/2 (SFRP1/2) [80, 81],
angiopoietins, and vascular endothelial growth factor(VEGF) [82, 83].
It has been demonstrated that MSCs can inhibit fibrosis via paracrine factors [84]. Chronic inflammation is amajor factor that drives the fibrosis process, which canalter the normal architectural structure of tissues andlead to deteriorated functioning. Because MSCs canbe used to reduce inflammation, they have become an
attractive therapeutic strategy for suppressing fibrosis.
MSC-derived conditioned medium (CM) was shownto attenuate liver fibrosis by reducing Th17 cells in aZhuang et al. J Biomed Sci(2021) 28:28

IDO-dependent manner [85]. MSC-secreted interleukin 1 receptor antagonist (IL-1Ra) was also shown to
inhibit stellate cell activation and decrease type I collagen expression, a key component of liver fibrosis [86].
Administration of MSC-CM also reduced fibrotic score
and collagen deposition in both bleomycin- and silicainduced lung injury models [87, 88]. In MSC-treatedcells, levels of HGF, KGF, and BMP-7 increased whilelevels of TGF-β1 and TNF-α decreased. These results
suggest that the anti-fibrotic effect of MSCs may be
mediated via paracrine mechanisms [88]. In supportof this, a bleomycin-induced lung injury model showedthat the stanniocalcin-1 (STC-1) secreted by MSCs in
response to TGF-β1 exerted antifibrotic effects by reducing oxidative stress, endoplasmic reticulum (ER) stress,
and TGF-β1 production in alveolar epithelial cells [89].
Likewise, MSCs were able to decrease the expression offibrosis-associated tissue inhibitor of matrix metalloproteinase 1 (TIMP)-1, to improve cardiac function in a
myocardial infarction model [90].
Mitochondrial transfer

Mitochondrial dysfunction is a hallmark of the aging
process, and has been implicated in the pathogenesisof numerous diseases [91]. MSC-based mitochondrialtransfer has therefore been a promising therapeuticstrategy, by either replenishing or replacing the damaged mitochondria in targeted diseased cells [92]. Studies have observed increased tunneling nanotube (TNT)and gap junction formation with mitochondrial transfer
between MSCs and injured epithelial/endothelial cells
under inflammatory or hypoxic conditions, and MSCderived mitochondria transfers could prevent apoptosisof recipient cells [93–95]. In addition, it was found that
iPSC-derived MSCs could attenuate alveolar damage andfibrosis via mitochondrial transfer by TNT [96]. The tissue origin of MSCs may affect mitochondrial transfer
ability. For example, iPSC-derived MSCs were shown
to be more effective at mitochondria transfer comparedwith MSCs derived from bone marrow [96]. Mechanistically, mitochondrial transfer was found to alleviate epithelial injury through mitochondrial Rho-GTPase Miro1
regulation in an asthma model [97].
Despite these beneficial findings of MSC-mediatedmitochondrial transfer, there are also potential risks, as
mitochondrial transfer can increase the risk of tumor
promotion. In acute myeloid leukemia (AML), NOX2
stimulated mitochondrial transfer from BMMSCs tocancer cells, and this promoted the survival of the cancer cells [98]. Mitochondrial transfer also increased
the resistance of leukemic cells to chemotherapeutic
agents, and transfer occurred bidirectionally [99, 100].
In an in vitro co-culture of BMMSCs and T cell acutePage 5 of 38

lymphoblastic leukemia (T-ALL) cells, upon inductionof oxidative stress by the addition of chemotherapeutic agents, T-ALL cells transferred their mitochondria
to BMMSCs, but received few mitochondria from the
BMMSCs, raising the chemoresistance of the T-ALL cells[99]. Neutralizing the cell adhesion molecule ICAM-1
and disrupting intercellular mitochondrial transfer
restored the sensitivity of the T-ALL cells to the chemotherapeutic agent [99].
Extracellular vesicle (EV) transfer

MSC-derived extracellular vesicles (EVs) have raised
increasing interest as a non-cellular alternative to MSCbased therapy, as this approach eliminates concernsof unintended lineage differentiation [101]. EVs referto exosomes, microvesicles, and apoptotic bodies, andare membrane-enclosed entities secreted by a cell in
response to stimulation or apoptosis. The size and contents of these vesicles are highly variable and heterogeneous, involving proteins, mRNAs, and miRNAs [101].
Their role in MSC-mediated cellular therapy remains elusive due to their heterogeneous nature, but it is currently
believed that they play an important role in many biological processes and intercellular communication [101].
Exosomes from MSCs have shown beneficial effects
in disease models of autoimmune uveitis [102], retinal
detachment [103], myocardial infarction [104], type 1
diabetes [105], wound healing [106], bone repair [107],burn injury [46], traumatic brain injury [108], spinal
cord injury [109], and several other conditions [110]. The
most commonly suggested mechanism responsible forthe effects of exosomes is via their capability to regulate
immune cells and immune microenvironments. MSCderived exosomes can suppress the expression of proinflammatory cytokines TNF-α, IL-1β, IL-6, IL-17, IFN-γ,
and MIP-1α in immune cells [103, 105, 109, 111]. Additionally, MSC-derived exosomes significantly increased
the levels of anti-inflammatory cytokines IL-4, IL-10,
and TGF-β in a type 1 diabetes animal model [105]. In a
drug-induced liver injury model, MSC-derived exosomesenhanced the local expression of cytokines TGF-β and
HGF, both of which are key factors in liver regeneration [112]. The underlying mechanism involved changes
in the immune cell population, including increased M2
polarization [106, 108, 109], increased Th2 and regulatory T cell differentiation [105, 112], decreased Th17
differentiation [111], and decreased local immune cell
infiltration [102].
In addition to promoting immunomodulation,
MSC-derived exosomes participate in other biological processes. MSC-derived exosomes were found topromote neoangiogenesis in diabetic and burn wounds
via increased VEGF-A expression, the Wnt4/β-cateninZhuang et al. J Biomed Sci(2021) 28:28

pathway, and increased tube formation and proliferationof endothelial cells [106, 113]. MSC-derived exosomes
also activate Akt, ERK, and STAT3 pathways and induce
expression of HGF, IGF1, NGF, SDF1, and TGF-β, which
critically regulate wound healing and tissue repair [114].
In addition, MSC-derived exosomes can aid in tissue
repair by enhancing autophagy and inhibiting apoptosis[103].
In contrast to microvesicles and exosomes from MSCs,
apoptotic bodies are entities specifically generated bycells during apoptosis. Apoptotic bodies containing
ubiquitin ligase RNF146 and miR328-3p were shown tohelp maintain MSC multipotency via the Wnt/β-catenin
pathway [115]. In support, it was recently shown that
apoptotic bodies released from donor MSCs improved
myocardial infarction via autophagy regulation in recipient cells [116].
The lack of consistent or standardized methods to isolate and identify EVs presents a challenge for current
therapeutics. A recent study has shown that compared toEVs, MSC-CM resulted in more effective immunomodulation [117]. Further studies are necessary to decipher the
optimal MSC culture conditions and the specific subpopulations of secreted components that contribute to themost effective therapeutic benefit.
Clinical applications of MSC-derived EVs have gained
increasing interest, as many of the safety concerns of
MSC-based therapy might be avoided, including undesired differentiation of implanted cells in tumor formation/promotion risks, and the cell-derived secondary
ischemic damage by vessel clotting. As MSC-derived EVs
are still in their clinical infancy, there is currently little
information on clinical safety. To monitor biodistribution, most of the in vivo studies utilize lipophilic dyes tolabel the EVs [118, 119]. While the injected MSC-derived
EVs migrated and accumulated at the injured tissue, theyalso aggregated in the lung, liver, and spleen [118, 119].
MSC safety consideration: Tumor initiation, promotion,and suppression

MSC-related cell therapy is a promising therapeuticstrategy because of the high immune modulation ability
and the absence of tumor initiation risk of MSCs. However, there is still concern that MSCs can pose a risk for
promoting tumor cell growth [120, 121]. MSCs sharesome characteristics with fibroblast cells, which are able
to transform into cancer-associated fibroblasts (CAFs)
in tumor niches. The tumor niche involves local fibroblasts, endothelial cells, immune cells, and cancer associated MSCs. Increasing evidence shows that the tumor
niche is not only trophic to cancer cells, but also highly
associated with tumor initiation and growth, and is able
to increase cancer stemness-related properties, including

Page 6 of 38

the capacity for cell migration, invasion, and chemotherapy resistance. Therefore, cancer treatment strategies
have expanded from solely targeting the tumor cells, toaltering the tumor milieu.
Since MSCs have an excellent ability for homing totumor sites, the possibility for therapeutic MSCs totransform into cancer-associated MSCs exists. Several
studies have examined the effect of MSCs on different
types of tumor cells. Not surprisingly, conclusions among
these studies are unclear (Fig. 2). Studies using MSCs
from different tissue origins, different cultivation processes, and different cancers can lead to diverse results
and interpretations.
On the other hand, taking advantage of the ability ofMSCs to home to tumor sites enables MSCs to serve as
therapeutic carriers that deliver anticancer agents toappropriate sites [122]. As highly progressive and latestage malignancies constitute a major health burden, forwhich current treatments are unsatisfactory and curative
therapies are unavailable, MSC-related drug carriers may
provide new hope for cancer treatments, particularly forlate stage cancers.
MSC Promotion effects on tumor cell growthand metastasis

The underlying mechanisms responsible for MSC tumor
promotion are complicated and diverse (Table 3). They
are classified below according to MSC type and signaling
pathway, and are listed systematically in Table 4 and summarized in Fig. 3.
Cell type
BMMSCsSeveral studies have examined the effects of MSCs on
tumor cell growth (Fig. 2). MSCs derived from humanbone marrow (hBMMSCs) have been shown to enhance
the motility of prostate cancer cells via SDF-1 regulationin vitro [123]. Additionally, hBMMSCs were reported topromote glioblastoma bone metastasis in vivo throughthe activation of SDF-1/CXCR4 and SDF-1/CXCR7
signaling [124]. It has also been shown that exosomes
derived from glioma cells induce hBMMSC transformation to a tumor-like phenotype by activating glycolysis[125]. hBMMSCs that were pre-challenged with hypoxia
increased tumor growth, cell proliferation, intra-tumoral
angiogenesis and M2 polarization of macrophages inlung adenocarcinomas. The underlying mechanism
involved downregulation of PTEN, PDCD4 and RECK
gene expression by miR-21-5p derived from hBMMSCs
exosomes [126]. Furthermore, hBMMSCs were shown
to mediate osteosarcoma and hepatocellular carcinoma(HCC) cell migration and invasion through the regulation of CXCR4 [127]. Human MSCs (hMSCs) promoteZhuang et al. J Biomed Sci(2021) 28:28

Page 7 of 38

Fig. 2 Promotion and suppression effects of MSCs on different cancer types. Data analysis from published studies listed in Tables 4 and 5, but
excluding engineered MSCs. N.R. not reported

HCC tumor growth via the MAPK pathway and promote metastasis by epithelial-mesenchymal transition(EMT) and integrin α5. Furthermore, hMSC treatment
promoted HCC progression, increased IL-6 and TNF-α
expression, and decreased the number of natural killer(NK) cells in tumor niches [128].
In addition to their paracrine effect, hBMMSCs also
promote colorectal carcinoma (CRC) and gastric cancer progression by directly differentiating to CAFs andexerting their trophic effects [129–131]. In colorectal adenocarcinomas, IL6 secreted from hBMMSCs
not only increased cancer cell CD133 expression via

activation of the JAK2/STAT3 pathway [132], but also
activated Akt and ERK in endothelial cells by inducing the secretion of endothelin-1 (ET-1) [133]. Furthermore, hBMMSC-secreted PAI-1 and NRG1 wereshown to promote CRC progression; the latter activates
the PI3K/AKT pathway in a HER2/HER3-dependent
manner [134, 135]. Indirect co-culture of CRCs withhBMMSCs enhanced the invasiveness of CRCs via suppression of RNA-binding protein PTBP1 [136]. The
up-regulation of cancer stemness-related properties
in CRCs is correlated with activation of the Notch signalling pathway by miR-142-3p, which downregulates

Zhuang et al. J Biomed Sci(2021) 28:28

Page 8 of 38

Table 3 MSC tumor promoting signaling pathways
Tumor promoting signaling pathways
TGF-β1
IL6
IL-8

Smad2/3, Akt/GSK-3β/β-catenin, PI3K/Akt, NF-κB, p38 MAPK
JAK2/STAT3
FAK

[159]
[132]
[140]

SDF-1
CXCL1
CXCR4
CCL5

CXCR4, CXCR7CXCR1/2
PI3K/Akt, Ras/Erk
CCR1/β-catenin/Slug, CCR5 → CSF1 secretion → recruitment of TAM and MDSC

[124]
[150]
[127]
[137, 142]

NRG1

HER2(HER3)/PI3K/AKT[41]

miR-21-5p
miR-410
miR-142-3p
miR-23b

Downregulation of PTEN, PDCD4 and RECK; M2 polarization
Downregulation of PTEN
Activating Notch signalling by downregulation of Numb
Downregulation of MARCKS

[126]
[158]
[136]
[145]

Direct contact

NOTCH[136, 144, 149]

Numb expression and is transmitted via hBMMSC
exosomes[136].
One approach to mimic the inflammatory niche is togenerate TNF-α-primed-hBMMSCs that secrete highlevels of CCL5, which is involved in the CRC-related
CCl5/CCR1/β-catenin/Slug signaling pathway that promotes tumor cell proliferation, EMT, migration, and invasion [137]. Activation of the Hedgehog signaling pathway
by hBMMSC-derived exosomes leads to increased tumor
cell growth in both gastric cancer and in osteosarcoma[138]. hBMMSC-secreted IL6 and IL-8 have been shownto increase tumor growth and metastasis in osteosarcomas by activation of the STAT3 and FAK signaling
pathways, respectively [139, 140]. Meanwhile, elevatedlevels of GRO-a, MCP-1, IL-6 and IL-8 in the tumor
microenvironment promoted osteosarcoma invasion andtransendothelial migration via cross-talk between tumor
cells and CAFs from hBMMSCs [141]. CCL5 secreted by
hBMMSCs increased the motility of breast cancer cells(BCCs) by activation of CCL5-CCR5 signaling [142]. Thissignalling also promotes BCCs to secret CSF1, which willbind to the CSF1 receptor on MSCs, tumor-associatedmacrophages and myeloid-derived suppressor cells, anddrive recruitment of myeloid-derived suppressor cells(MDSCs) and tumor-associated macrophage (TAMs)[143]. Elevated CCL5 (RANTES), CCL2 (MCP-1), andCXCL8 (IL-8) in TNFα/IL-1β primed triple-negative
subtype of breast cancer cells (TNBCs): hBMMSCs cocultures increase BCC lung metastases [144]. Moreover,physical interactions between TNBCs and hBMMSCs
primed with TNFα or IL-1β, activates Notch1, whichleads to CXCL8 production and increased tumor cell
migration and invasion [144]. Exosomes derived fromhBMMSCs promote the acquisition of dormant phenotypes by suppressing MARCKS expression in abone marrow-metastatic human breast cancer cell line

through miR-23b [145]. In head and neck squamous cell
carcinoma (HNSCC) and esophageal squamous cell carcinoma (ESCC), increased tumor cell invasion was correlated with induction of ALP and MMP9 activity by directcontact between tumor cells and hBMMSCs, and by activation of the Gremlin1-dependent TGF-β/BMP signaling
pathway by hBMMSC-CM, respectively [146, 147]
ADMSCs

The effect of MSCs on promoting tumor cell growth
may be mediated via angiogenic factors VEGF, Ang-1,
PDGF, and IGF and SDF-1 [148]. In addition, adipose
tissue-derived mesenchymal stem cells (ADMSCs)differentiated CAFs promote the EMT of lung cancers
by activating the NOTCH pathway [149]. hADMSCsecreted CXCL1/8 enhances the growth and angiogenesis of BCCs by activating CXCL1/8-CXCR1/2 signaling[150]. hADMSCs and human amniotic fluid‐derived stem
cells (hAFMSCs) increase ciprofloxacin resistance inrenal cell carcinomas (RCCs) and bladder cancer cells[151]. Additionally, elevating the expression of MMP2
and MMP9 in ovarian cancer cells causes increased
tumor growth and metastasis in both direct and indirect co-cultures with hADMSCs [152]. LL-37, which
is usually overexpressed in ovarian cancer, can recruitand stimulate MSCs to release trophic factors, which
increase tumor growth and angiogenesis [153]. In addition to MSCs, the CM and the EVs derived from human
ADMSCs showed the ability to increase tumor growthand migration and to decrease H­ 2O2–induced tumor
cell apoptosis [154]. Meanwhile, the hADMSC-CM andexosomes were shown to increase doxorubicin resistanceand tumor cell migration either by increasing breast cancer resistance protein (BCRP) levels or by activating theWnt signaling pathway in BCCs, respectively [155, 156].

SH2+ ­SH3+ ­CD29+ ­CD44+ ­CD71+ ­CD90+­CD106+ ­CD120a+ ­CD124+ ­CD14− ­CD34−­CD45−
CD73+ ­CD90+ ­CD105+ ­CD45−
CD31− ­CD45−

Not stated
CD44+ ­CD90+ ­CD34−
CD44+ ­CD105+ ­CD14− ­CD34− ­CD45−

Sh2+ ­SH3+ Thy-1+ ­CD44+ ­CD34− ­CD45−
CD29 CD44 CD73 CD90 CD105 CD166

Human bone marrow of healthy donor

Human adipose tissue from trochanteric fatof healthy donor

Human adipose tissue

Mouse adipose tissue

Human adipose tissue from individuals
receiving abdominoplasty

Human adipose tissue of individuals receiv‑
ing abdominoplasty or mammoplasty

Human umbilical cord Wharton’s jelly(human umbilical cord perivascular cells)

Human umbilical cord blood of healthy
donors

Not stated

CD133+ ­CD271+ ­CD105+ ­CD3− ­CD14− ­CD19− Increased tumor EMT, invasion, and migration;­CD38− ­CD66b−
decreased tumor proliferation and increased
tumor apoptosis
CD105 CD73 CD90 CD45 CD34 CD14 CD19
HLA-DR

CD105+ ­CD90+ ­CD166+ ­CD73+ ­CD45− ­CD31− Increased AC-LCSC tumor cell proliferation­CD34−and expression of CSC markers ­(ALDH+ and­CD133+ cell population)

Human adipose tissue stem cell line

Human umbilical cord of healthy donor

Human umbilical cord of healthy donor

Human umbilical cord Wharton’s jelly

Increased tumor cell proliferation anddecreased tumor cell apoptosis

Increased migration capacity

Not stated

Increased tumor growth, cancer cell prolifera‑tion, intra-tumoral angiogenesis and M2
polarization of macrophages

Increased tumor growth

Increased tumor growth and migration; no
significant effect on TMZ response

Increased cancer cell migration; no significant
effect on cancer cell proliferation, TMZ
response, CSC traits

Increased tumor growth; decreased apoptosisand ­H2O2-induced cancer cell death

Increased tumor migratory capacity

Increased tumor growth

Increased tumor cell proliferation

Increased tumor metastasis

tumor-like phenotype transformation

EffectHuman bone marrow

Lung cancer

CD73+ ­CD90+ ­CD105+

Surface marker

Human bone marrow from ScienCell
Research Laboratories

Brain cancer

Cancer type/MSC source

Table 4 MSC promotion effects in cancers

[161]

[158]

[159]

[149]

[126]

[160]

[162]

[282]

[154]

[282]

[148]

[281]

[124]

[125]

Ref.

(2021) 28:28

MSC-CM and in vivo co-transplantation

Reduced PTEN expression mediated by the
MSC-EV-transmitted miR-410

Exosomes derived from MSCs activatedSmad2/3, Akt/GSK-3β/β-catenin, NF-kB, ERK,JNK, and p38 MAPK signaling pathway by
TGF-β1ADMSC-differentiated CAFs promoted cancer
EMT by NOTCH pathway

Downregulated PTEN,
PDCD4 and RECK gene expression in cancer
cells largely through miR-21-5p, which
derived from EVs of MSCs pre-challenged
with hypoxia

Exosomes
CD133+ GBM secreted MCP-1/CCL2 andSDF-1/CXCL12 induce migration of MSCs

Cytokines from MSCs-CM (ex. CCL2, PDGF-C,
Sema-7A, periostin, IL6)

MSCs-CM

Co-injection in vivo
Co-culture or MSCs-CM

MSC-secreted conditioned medium increases
vimentin, MMP2, and NRAS expression

Higher mRNA expression levels of angiogenic
factors (VEGF, Ang-1, PDGF, and IGF) andSDF-1(CXCL12) in MSCs

MSC-EVSDF-1/CXCR4 and SDF-1/CXCR7 signaling

Glioma cell-derived exosomes, upregulating
the levels of
Glut-1, HK-2, and PKM-2, activating glycolysis
in MSCs

Factors/mechanisms

Zhuang et al. J Biomed Sci
Page 9 of 38

CD73+ ­CD90+ ­CD105+ ­CD34− ­CD45−
CD29+ ­CD44+ ­CD73+ ­CD90+ ­CD105+ ­CD166+ Increased tumor-initiating ability and tumor
growthCD49c+ ­CD73+ ­CD90+ ­CD105+ ­CD34− ­CD45− Increased tumor growth, invasion; decreased­CD184− ­CD106−
survival
Not stated

Not stated

Not stated

Not stated

Human bone marrow of healthy donor

Human bone marrow of healthy donor

Human bone marrow from sternum of
healthy donor

Human bone marrow from iliac crest ofhealthy donor

Human bone marrow from the iliac crestof the patient following bone defectreconstruction

Human bone marrow from the femoral
head during hip-replacement surgery

Human bone marrow from ATCC​

Not stated

CD44+ ­CD90+ ­CD34− ­CD45−

Human umbilical cord Wharton’s jelly ofhealthy donor

Human adipose tissue from liposuction

Renal cancer

CD29+ ­CD44+ ­CD73+ ­CD90+ ­CD105+ ­CD166+ Increased tumor growth, angiogenesis, and
MHC-DR+ ­CD14− ­CD34− Flk-1−
metastasis

Human bone marrow of healthy donor

[130]

[128]

[127]

[165]

Ref.

[137]

[136]

[136]

[133]

[135]

[132]

[134]

Not explored[151]

Induction of HGF synthesis via RNA transferred [163]by MSC-MVs activated AKT and ERK1/2
signaling

TNF-α-primed-MSCs secreted high levelof CCL5 which further involved cancer
cells’ CCl5/CCR1/β-catenin/Slug signaling
pathway

MiR-142-3p contained in exosomes derived
from MSCs promoted the Notch signal‑ling pathway by downregulating Numb incancer cells

Suppressed RNA-binding protein PTBP1 byindirect co-culture with MSCs

MSC-secreted IL6 induced ET1/AKT or ERK
pathway in endothelial cells to promoteangiogenesis

MSC-secreted NRG1 activated HER2/HER3dependent PI3K/AKT pathway

MSC-secreted IL6 increased cancer cell CD133
expression by activation of JAK2/STAT3

MSC-secreted PAI-1 promoted cancer cell
migration

MSC-differentiated into CAFs; paracrine effects [129]of MSCs;

MSC-differentiated CAFs expressed PDGFR tomediate tumor growth and metastasis

Activated pERK signaling pathway and overexpressed integrin α5 in HCC; decreased
NK cell marker CD56 and increased IL-6 andTNF-α in tumor niche

MSC-dependent activation of the CXCR4,
PI3K/Akt, Ras/Erk pathways

Decreased TGFβ1 and MMP2 expression incancer cells

Factors/mechanisms(2021) 28:28

Increased Ciprofloxacin resistance

Increased tumor growth

Increased tumor cell proliferation, EMT, migra‑
tion, and invasion

Increased cancer cells stem cell-like traits

Increased tumor growth, cell proliferation,
invasion and cancer stemness-related
properties

Increased tumor growth and angiogenesis

Increased migration capacity

CD29+ ­CD44+ ­CD73+ ­CD90+ ­CD105+ ­CD166+ Increased tumor growth
MHC-DR+ ­CD14− ­CD34− Flk-1−

Human bone marrow of healthy donor

Colorectal cancer

Not stated

Human bone marrow from ATCC​
Increased tumor growth and metastasis

CD44+ ­CD73+ ­CD90+ ­CD105+ ­CD146+ ­CD34− Increased tumor growth, migration and inva‑­CD45−
sion

Human bone marrow from patients withorthopedic surgery

Increased tumor progression, but decreased
pulmonary metastasis

EffectCD44+ ­CD90+

Surface marker

Human bone marrow MSC cell line

Liver cancer

Cancer type/MSC source

Table 4 (continued)

Zhuang et al. J Biomed Sci
Page 10 of 38

CD29+ ­CD44+ ­CD105+ ­CD166+ ­CD90+ ­CD73+ Increased tumor lung metastases
CD14− ­CD34− ­CD45−HLA-DR− ­CD19−
CD105+ ­CD45−
Not stated
Not stated

Human bone marrow from Lonza

Human bone marrow of healthy donor

Human bone marrow of healthy donor

Human bone marrow of healthy donor

Increased skin invasion and metastasis

Increased tumor cell migration
Increased Doxorubicin resistance

Human adipose tissue from patients under‑ CD44+ ­CD105+ HLA-ABC+ ­CD29+ ­Fik1+
going tumescent liposuction
CD45− C­ D31− ­CD34− ­CD106− ­CD184−
CD73+ ­CD90+ ­CD105+
CD73+ ­CD90+ ­CD105+ ­CD34−

Human adipose tissue from ScienCell
Research Laboratories (Carlsbad, CA)

Human adipose tissue from liposuction

[284]

[143]

[283]

[152]

[153]

[151]

Ref.

[145]

[285]

[142]

[155]

MSC dose dependent[286]

MSC-secreted conditioned medium promoted [156]
BCRP protein expression in cancer cells

Exosomes derived from MSCs activated Wnt
signaling pathway

CXCL1/8 secreted by MSCs activated CXCL1/8- [150]CXCR1/2 signaling in cancer cells

miR-23b contained in exosomes derived from
MSCs
suppressed MARCKS expression

Not explored

CCL5 secreted by MSCs activated CCL5-CCR5
signaling in cancer cells

Elevated CXCL8 (IL-8), CCL2 (MCP-1), and CCL5 [144](RANTES) by TNFα/IL-1β primed TNBC:MSC
co-cultures

Tumor and stroma physical interactions acti‑[144]
vated Notch1 by TNFα or IL-1β, which further
lead to CXCL8 production

Activation of EGFR signaling pathway

MSCs involve in driving recruitment of TAMs
and MDSCs

Not explored

Elevated the expression of MMP2 and MMP9

LL-37 recruited MSCs, which release trophic
factors that initiate angiogenesis and/or dif‑ferentiate into blood vessel-supporting cells

Not explored

Factors/mechanisms(2021) 28:28

Increased tumor metastatic spread

Increased tumor growth and angiogenesis

Human adipose tissue from women
CD29 CD166 CD73
(BMI > 30) undergoing liposuction from the CD105 CD90 CD11b CD31 CD34 CD45 HLAsubcutaneous abdominal adipose tissue
DR

Acquisition of dormant phenotypes includ‑ing decreased tumor cells proliferation,
the abundance of stem cell–like surface
markers, invasion capacity, and sensitivity to
docetaxel

Increased tumor growth and bone metastasis

Increased tumor motility, invasion andmetastasis

Increased tumor cell migration and invasion

Not stated
Not stated

Human bone marrow of healthy donor

Increased tumor metastasis

Increased tumor growth and cell proliferation

Increased tumor growth and metastasis

Increased tumor growth and angiogenesis

Increased Ciprofloxacin resistance

EffectHuman bone marrow of healthy donor

Not stated

Human bone marrow of healthy donor

Breast cancer

Human adipose tissue from omentum ofpatient with recurrent adenocarcinoma of
endometrium and ovary
CD44+ ­CD29+ ­CD90+ ­CD105+ ­CD34− ­CD45−­CD11b−

CD105+ ­CD73+ ­CD90+ ­CD34−

Human adipose tissue from omentum of
normal donors

Endometrial cancer

CD90 CD105 CD106 CD117 CD146 CD56
CD166 CD29 CD44 CD14 CD31 CD34 HLADR

CD44+ ­CD90+ ­CD34− ­CD45−

Surface marker

Healthy human donor

Ovarian cancer

Human amniotic fluid from healthy preg‑
nant womenCancer type/MSC source

Table 4 (continued)

Zhuang et al. J Biomed Sci
Page 11 of 38

Not stated
CD73+ ­CD90+ ­CD105+
CD34− ­CD45− ­CD19− ­CD14−
CD73+ ­CD90+ ­CD105+
CD34− ­CD45− ­CD3−

Human bone marrow from TaKaRa Biotech‑
nologyHuman bone marrow of healthy donor

Human bone marrow

Human bone marrow from patients during
hip-replacement surgery

CD73 + CD90 + CD105 + CD19- CD34-

Not stated

Human bone marrow from ATCC​

Head and neck cancer

CD29+ ­CD44+ ­CD105+
CD45− HLA-DR−

Human bone marrow

Gastric cancer

CD29+ ­CD44+ ­CD105+
CD45− HLA-DR−

Human bone marrow

Increased tumor cell invasion

Increased tumor cells viability and invasion

Increased tumor cell growth

Increased tumor cell proliferation

Increased tumor cell invasion and transen‑
dothelial migration

Increased tumor cell growth and metastasis

Increased tumor cell growth

CD44+ ­CD73+ ­CD90+ ­CD105+ ­CD146+ ­CD34− Increased tumor growth, migration and inva‑­CD45−
sion

Human bone marrow from patients withorthopedic surgery

Increased tumor growth and metastasis tolungIncreased tumor metastasis to bone and liver

Not stated

Not stated

Increased tumor cell migration and invasion

Increased tumor cells proliferation and migra‑
tion

Increased tumor cell invasion and metastasis

EffectHuman bone marrow from the proximal
femur during orthopedic surgery

Bone cancer

Resident MSCs of bone and liver

Melanoma

Mouse bone marrow from femurs
CD90+ ­CD34−/CD45−

CD29+ ­CD44+ ­CD90+ ­CD34− HLA-DR−

Human umbilical cord of healthy donors

Prostate cancer

Not statedSurface marker

Human umbilical cord of healthy donor

Cancer type/MSC source

Table 4 (continued)

Induction of ALP and MMP9 activity

MSCs recruitment and presence of CAF-likemyofibroblastic phenotypes by tumorderived HDGF

Activation of Hedgehog signaling pathway by
MSC-derived exosomes

Not explored

MSCs trans-differentiate into CAFs, increas‑
ing GRO-a, MCP-1, IL-6 and IL-8 levels in thetumor microenvironment

Paracrine effect of IL-8 through activation of
FAK pathway

Activation of Hedgehog signaling pathway by
MSC-derived exosomes

MSCs-dependent activation of the CXCR4,
PI3K/Akt, Ras/Erk pathways

MSC-secreted IL6 activated tumor STAT3
signaling pathway

MCC interact with resident MSCs at theperivascular space through co-expressed
CD146 and CXCL12-CXCR4 signaling

SDF1a secreted by MSCs

MSC-CM inhibited E-cadherin expression,increased the expression of N-cadherin,
ZEB1 and PCNA through activation of the
ERK pathway

IL-8 and IL-6 secreted by MSCs activated the
autocrine IL-8
and IL-6 signaling in cancer cells and induced
CD44 + /CD24 − cells

Factors/mechanisms

[146]

[131]

[138]

[288]

[141]

[140]

[138]

[127]

[139]

[287]

[123]

[157]

[286]

Ref.

Zhuang et al. J Biomed Sci(2021) 28:28
Page 12 of 38

CD44+ ­CD90+ ­CD34− ­CD45−
CD44+ ­CD90+ ­CD34− ­CD45−

Human amniotic fluid from healthy preg‑
nant women

CD29+ ­CD44+ ­CD73+ ­CD90+ ­CD45− ­CD31−

Surface marker

Human adipose tissue from liposuction

Bladder cancer

Human bone marrow

Esophageal cancer

Cancer type/MSC source

Table 4 (continued)

Increased Ciprofloxacin resistance

Increased Ciprofloxacin resistance

Increased tumor cell proliferation, viability andinvasion

EffectNot explored

Not explored

Gremlin1 derived from MSC-CM is related to
TGF-β/BMP signaling pathway

Factors/mechanisms

[151]

[151]

[147]

Ref.

Zhuang et al. J Biomed Sci(2021) 28:28
Page 13 of 38

Zhuang et al. J Biomed Sci(2021) 28:28

Page 14 of 38

Fig. 3 Schematic diagram of tumor promoting mechanisms of MSCs. MSCs influence cancer cells and immune cells to promote tumor cellproliferation, invasion, migration and metastasis. Secreted microRNA-containing exosomes, soluble factors, and contact-dependent signaling
pathways are summarized

UCMSCs and WJMSCs

hUCMSCs promote proliferation and migration of BCCs
by activating ERK signaling, including down-regulating
E-cadherin expression, and up-regulating N-cadherin,
ZEB1 and PCNA expression [157].
The EVs derived from hUCMSCs also have the ability to increase tumor cell proliferation and to decrease
tumor cell apoptosis in lung adenocarcinomas via transmission of miR-410, which reduces PTEN expression[158]. Additionally, exosomes derived from hUCMSCs
increased tumor EMT, invasion, and migration throughTGF-β1-mediated signaling pathways [159]. Furthermore, ­CD133+ glioblastoma stem cells exhibited the ability to recruit hUCBMSCs, which can further promotetumor growth in vivo, via exosomes containing MCP-1/
CCL2 and SDF-1/CXCL12 [160].
An increase in the cancer stemness-related ­ALDH++and ­CD133 cell populations was observed in lung

Zhuang et al. J Biomed Sci(2021) 28:28

adenocarcinomas treated with Wharton’s Jelly mesenchymal stem cell CM (WJMSC-CM) [161]. WJMSC-CM also
showed effects of increasing tumor growth and migrationof glioblastoma cells by secreted cytokines (eg. CCL2,
PDGF-C, Sema-7A, periostin, IL6) [162]. Besides thecytokines and chemokines secreted by MSCs, WJMSC
microvesicles (MVs) transfer RNA to RCCs, which
induces HGF synthesis and further activates AKT and
ERK1/2 signaling [163].
Signaling pathways
Chemokine signaling

Chemokine signaling plays an important role in MSCdependent tumor promotion (Fig. 3). ­CD133+ glioblastoma stem cells induce hUCMSC migration to tumor
regions by secreting CCL2 and CXCL12. Once in thetumor region, MSCs then promote tumor proliferationand glial invasiveness [160]. In addition, SDF-1 secreted
from hBMMSCs promotes neuroblastoma migration andinvasion via CXCR4 and CXCR7 [124]. hBMMSCs alsoenhance osteosarcoma and HCC cell migration and invasion by activating the AKT and ERK pathways of tumor
cells via CXCR4 [127]. These observations suggest thatchemokine signaling may be involved in bone metastasis.
Furthermore, Chaturvedi et al. demonstrated that there isa delicate crosstalk among BCCs, hBMMSCs and TAMs/
MDSCs involving chemokine signaling, and that there
are two signaling loops among these cell types. In thesecond loop, CCL5 secreted from MSCs activates BCCs
via CCR5, which promotes the BCCs to secret CSF1 andfurther recruits TAMs and MDSCs to the tumor region[143]. In addition, hBMMSCs weakly enhance the invasiveness and metastasis of metastatic human BCCs
through CCL5-CCR5 signaling regulation [142]. CCL5
secreted from TNF-α-primed hBMMSCs also showed
the ability to promote CRC progression and EMT via
the CCL5/CCR1/β-catenin/Slug signaling pathway [137].
In addition to tumor and immune cells, chemokine
signaling affects other cells in tumor niches. For example, CXCL1/8 derived from hADMSCs can enhance
the migration and tube formation of human umbilicalvein endothelial cells (HUVECs) in vitro by CXCR1 andCXCR2, which promote angiogenesis in a breast tumor
xenograft mouse model [150]. CXCL8 derived fromhBMMSCs was also shown to activate FAK signaling in
osteosarcomas and to promote tumor metastasis [140].
TGF‑β signaling

TGF-β is well known as an EMT promotor, but it can also
induce cell cycle arrest and apoptosis [164]. In lung cancer cells, hUCMSCs have been shown to promote tumor
cell EMT, invasion, and migration, but also to decrease
tumor proliferation and promote tumor apoptosis byPage 15 of 38

TGF-β1 from exosomes secreted by MSCs. The TGF-β1
activates Smad2/3, Akt/GSK-3β/β-catenin, NF-kB, ERK,JNK, and the p38 MAPK signaling pathway in cancer
cells. Silencing TGF-β1 or inhibiting exosome secretion can eliminate the MSC-dependent effects on cancer
cells described above [159]. hBMMSCs also increased
tumor progression, but decreased pulmonary metastasis with decreased TGFβ1 levels in HCC [165]. Furthermore, Hong et al. demonstrated that hBMMSC-CM canenhance the proliferation, viability and invasiveness ofesophageal cancer cells via Gremlin1, which activates
the TGF-β/Smad2/3 signaling pathway by inhibiting the
BMP4/Smad1/5/8 signaling pathway in cancer cells [147].
MicroRNA signaling

Accumulating evidence shows that EV-derived miRNA
contributes to tumor initiation, angiogenesis, drug resistance, metastasis and immune suppression in cancer[166]. EVs derived from hBMMSCs pre-challenged withhypoxia can promote tumor growth, cancer cell proliferation, invasion, intra-tumoral angiogenesis and M2
polarization of macrophages in non-small cell lung cancer cells. This occurs via miR-21-5p, which decreases
PTEN, PDCD4 and RECK protein levels in cancer cells
while enriching for C­ D163+CD206+, M2 macrophagerelated cell surface marker macrophages, and decreasing the ­CD40+CD86+, M1 macrophage-related cellsurface marker macrophage population. Transfecting
miR-21-5p inhibitor or re-overexpressing PTEN abrogated the tumor promoting and M2 polarization effects
that the hypoxia pre-challenged EVs induced [126]. Donget al. also reported that miR-410 derived from hUCMSCsecreting EVs repressed PTEN protein levels in lungadenocarcinoma cells, further increased tumor cell proliferation, and decreased tumor cell apoptosis [158].
miRNA is also reported to be involved in the dynamics of the cancer stem cell population. Increased cancer stem cell-like traits, including sphere formation,­Lgr5+CD133+ population, colony formation, drug resistance, and tumourigenesis, were reported in CRCs upontreatment with hBMMSC-derived exosomes that transmitted miR-142-3p. Mechanistically, it was found thatmiR-142-3p inhibits the expression of the Numb gene,which results in increased mRNA and protein levelsof Notch target genes Hes1, P21, and cyclin D3 mRNA[136]. On the other hand, Ono et al. demonstrated thatmiR-23b delivered via hBMMSC-derived exosomescaused bone marrow–metastatic human breast cancer cells to acquire dormant phenotypes, characterized
by decreases in tumor cell proliferation, tumourigenic
capacity, ­CD44+ population, invasion capacity, and sensitivity to docetaxel. The miR-23b may exert its effects bytargeting MARCKS [145].

Zhuang et al. J Biomed Sci(2021) 28:28

MSC suppression effects on tumor growth

While MSCs utilize diverse mechanisms for tumor promotion, they suppress tumor growth mainly by inducing
apoptosis of tumor cells. MSCs have been shown to suppress the growth of breast [167–169], brain [148, 170–174], lung [170, 175], liver [175, 176], ovarian [167, 177,178], bone [167, 179], esophageal [168], bladder [180],
colorectal [170] and hematological malignancies [181–183]. The underlying mechanisms responsible for MSC
tumor suppression are classified below as well in Table 5,
and are summarized in Fig. 4.
Apoptosis, autophagy and senescence

The majority of MSC tumor suppressing mechanisms
involve increasing tumor cell apoptosis and impeding cell
cycle progression. Upregulation of caspase-3, caspase-9,
p16, p21, p53, TRAIL, pro-apoptotic BAX, ATG5, ATG7,BECLIN1 and cellular ­H2O2 levels [148, 167–170, 173,
180, 182]; activation of Smac/DIABLO [173]; and downregulation of survivin, XIAP, cyclin D1, Cdk4, Cdk6, cyclin A2, cyclin E1, AKT/pAKT, Bcl-2, β-catenin, c-Myc,
pro-caspase-7, PCNA, Bcl-xL and MMPs have been
demonstrated to be involved in the MSC-dependent
tumor cell apoptosis seen with MSC-CM, MSC cell lysate(CL) and with direct cell–cell interaction [167, 168, 170–
176, 178, 180].
Boosting immunity

The immunomodulation ability of MSCs is also correlated with tumor suppression. Lin et al. demonstrated
that 3 kDa MWCO-WJMSC-CM concentrate can induce
immunogenic cell death in lymphoma cells, whichshowed decreased viability and increased apoptosis, aswell as increased levels of the ER stress markers eLF2a
and XBP-1. Increased levels of surface damage-associated molecular pattern markers ecto-CRT, ecto-Hsp70
and ecto-Hsp90, as well as extracellular ATP and highmobility group box 1 were also observed. When cocultured with WJMSC-CM-treated lymphoma cells, dendritic cells had enhanced CD80 and CD86 expression. Yet
lymphoma cells treated with WJMSC-CM concentrate
had decreased CD47 and PD-L1 expression [181].
Anti‑angiogenesis

In addition to directly inhibiting tumor cell growth,
coculturing with hBMMSCs or hUCBMSCs decreased
angiogenesis in glioblastoma. The underlying mechanism
may involve the down-regulation of PDGF-BB and IL1β
secretion or decreases in FAK, VEGF or Akt [184, 185].
Another attractive source of MSCs, human endometrial
mesenchymal stem cells (EnSCs), also show an ability todecrease tumor growth and to increase angiogenesis in
ovarian cancer by inhibiting AKT phosphorylation andPage 16 of 38

decreasing expression of VEGFA and HIF-1α, possibly
via nuclear translocation of FoxO3a [186].
Anti‑migration and invasion

hUCBMSCs are also reported to decrease glioblastoma
cell invasion and migration by increasing PTEN or Mad1
expression and downregulating PI3K/AKT, c-Myc/ERK
or EGFR/c-Met activities [187, 188]. Inhibition of Wnt
signaling has been shown to decrease tumor growth andmigration after treatment with hUCMSC- or hADMSCCM in bile duct cancer and breast cancer, respectively[189, 190].
Other mechanisms

Human BMMSC-secreted oncostatin M (OSM) has beenreported to inhibit tumorigenicity and EMT by activating the OSM/STAT1 signaling pathway in lung adenocarcinoma cells [191]. Decreased cancer cell proliferation
was also correlated with suppressed NF-κB expression
and activity in HCCs and BCCs by MSCs derived fromfetal bone marrow or fetal dermal tissue [192]. Vascularwall-resident MSCs as well as hBMMSCs displayed acapacity for decreasing the risk of lung metastasis afterradiation-induced injury in breast cancer and melanoma
by downregulating endothelial MMP2 and SASP factors
CCL2 and Plau/uPA, which were induced by radiation
injury [193]. In addition to suppressing tumor progression, hUCMSCs promote granulocytic differentiation of
immature myeloid cancer cells in acute promyelocytic
leukemia (APL), which drives the disease into remission
by activating MEK/ERK pathways [194].
Engineered MSCs

Another promising strategy to treat progressive malignancy is the use of engineered MSCs, which show aremarkable ability to suppress tumor progression [195].
UCBMSCs with exogenous overexpression of CXCR1and CXCR4 displayed enhanced tropism towards gliomas[196]. In addition, irradiation of glioma cells enhanced
IL-8 expression, which promoted the tropism of hUCBMSCs equipped with TRAIL migration to tumors, andfurther induced tumor cell apoptosis [197]. hBMMSCs
overexpressing TRAIL can also induce apoptosis in
CD133-positive primary glioma cells in vitro [198]. Modified interleukin-12 (IL-12p40N220Q; IL-12 M), which
enhances expression of the IL-12p70 heterodimer that isnecessary for induction of Th1 and CTL immunity, wasoverexpressed in hUCBMSCs and found to significantly
decrease tumor growth and angiogenesis, as well as toincrease the survival of glioma-bearing mice and to confer tumor-specific long-term T-cell immunity [199].
In human glioma studies, IL-24-hUCMSCs promoted
tumor cell apoptosis, and IFN-beta-hBMMSCs wereNot stated
CD44+ ­CD105+ ­CD34− ­CD38− ­CD45−
CD13+ ­CD44+ ­CD90+ ­CD105+ ­CD14− ­CD34−­CD45−
CD29+ ­CD44+ ­CD90+ ­CD105+
CD29+ ­CD44+ ­CD73+ ­CD90+ ­CD105+ ­CD166+ Decreased tumor growth, migration; induced­CD14− ­CD31− ­CD45− ­Lin1−
differentiation; no significant effect insurvival
CD13+ ­CD44+ ­CD90+ ­CD105+ ­CD14− ­CD34−­CD45−
CD73 CD105 CD90 CD45 CD34 CD14 CD11b
HLA-DR
CD29+ ­CD105+ ­CD34− ­CD45−
CD13+ ­CD29+ ­CD44+ ­CD73+ ­CD90+ ­CD105+­CD14− ­CD34− ­CD45− HLA-DR−

Human bone marrow of healthy donor

Human bone marrow of healthy donor

Human subcutaneous adipose tissue of
18–30 years old mothers receiving cesar‑
ean sections

Human adipose tissue from liposuction

Human adipose tissue from patients receiv‑
ing liposuctions (commercial)

Human umbilical cords of 18–30 years oldmothers receiving cesarean section

Human umbilical cord of healthy donor

Human umbilical cord from the cell libraryof the Chinese Academy of Science

Human umbilical cord Wharton’s jelly ofhealthy donor

Decreased tumor growth and migration
capacity

CD29+ ­CD81+

CD29+ ­CD81+
CD29+ ­CD81+

CD29+ ­CD81+
CD29+ ­CD81+

Human umbilical cord blood of healthy
donor

Human umbilical cord blood of healthy
donor

Human umbilical cord blood of healthy
donor

Human umbilical cord blood of healthy
donor

Human umbilical cord blood of healthy
donorsDecreased tumor growth

G0/G1 cell cycle arrest; decreased cyclin D1/
Cdk4 and cyclin D1/Cdk6 expression

Decreased EGFR and c-Met expression, activ‑
ity, and physical association

Increased cancer cell Mad1 expression
represses c-Myc activity and further
decreases activity of ERK

Co-culture with MSCs downregulated FAK,
VEGF, AKT

Co-culture with MSCs increased PTEN expres‑sion and downregulated PI3K/AKT pathway
in cancer cells

MSC-EVMSC-CM mediated cell cycle arrest andsenescence of cancer cells by downregulat‑
ing cyclin D1 and upregulating expressionof p21 and p16

Engineered IL-24-secreting MSCs induced
tumor cell apoptosis

Direct cell interaction

Increased apoptosis; G0/G1 cell cycle arrest
Upregulation of caspase-3 and caspase-9 anddownregulation of survivin and XIAPEngineered BMP4-secreting MSCs had addi‑
tional effect of improved survival

Paracrine effects by MSC-secreted cytokines

Increased apoptosis; G0/G1 cell cycle arrest
Upregulation of caspase-3 and caspase-9 anddownregulation of survivin and XIAPEngineered IFNβ-expressing MSCs

Engineered TRAIL-expressing MSCs induced
apoptosis of glioma cells

MSC-EV

Coculture with hBMMSCs decreased PDGF-BB
and IL1β secretion

Factors/mechanisms

[172]

[188]

[188]

[185]

[187]

[281]

[171]

[200]

[290]

[170]

[204]

[289]

[170]

[201]

[198]

[281]

[184]

Ref.

(2021) 28:28

Decreased migration and invasion capacity

Decreased invasion capacity

Decreased tumor growth and angiogenesis

Decreased tumor cell proliferation

Human umbilical cord Wharton’s jelly from Not stated
CryoSave

Decreased cancer stem-like cells proliferation

Decreased tumor growth

Decreased cancer stem cell proliferation

Decreased cancer cell proliferation

Decreased tumor growth and formation

Decreased cancer cell proliferation

Decreased cancer cell proliferation andincreased animal survival

Inducing apoptosis in CD133-positive primary
glioma cells

CD29+ ­CD44+ ­CD105+ ­CD166+ ­CD90+ ­CD73+ Decreased tumor cell proliferation
CD14− ­CD34− ­CD45−HLA-DR− ­CD19−

Human bone marrow from Lonza

Decreased tumor growth and angiogenesis

EffectCD44+ ­CD90+ ­CD105+

Surface marker

Human bone marrow from femoral head ofindividuals undergoing hip-replacement
surgery

Brain cancer

Cancer type/MSC source

Table 5 MSC suppression effects in cancers

Zhuang et al. J Biomed Sci
Page 17 of 38

CD31− ­CD45−
CD29+ ­CD44+ HLA-ABC+ ­CD34− ­CD45− HLADR−
Not stated

Not stated
Not stated
Not stated

Human umbilical cord blood of healthy
donorsHuman umbilical cord blood of healthy
donorsHuman umbilical cord blood of healthy
donorsHuman umbilical cord blood of healthy
donorsHuman umbilical cord blood from Medi‑post Co

Human umbilical cord blood of healthy
donorsDecreased XIAP expression resulted in activa‑tion of caspase-3 and caspase-9, downregu‑
lated AKT pathway and activated Smac/DIABLO

Factors/mechanisms

Engineered IL-12 M-secreting MSCs

Reduced the number of cyclin D1-positivecancer cells

Engineered TRAIL-expressing MSCs induced
apoptosis of glioma cells

CD13+ ­CD44+ ­CD90+ ­CD105+ ­CD14− ­CD34−­CD45−
CD29+ ­CD44+ ­CD73+ ­CD90+ ­CD105+ ­CD14−­CD34− ­CD45− HLA-DR−
CD13+ ­CD44+ ­CD90+ ­CD105+ ­CD14− ­CD34−­CD45−

CD105+ ­CD90+ ­CD166+ ­CD73+ ­CD45− ­CD31− Decreased SCC-LCSC tumor cell proliferation­CD34−and expression of CSC markers
CD105+ ­CD90+ ­CD73+ ­CD45− ­CD34−
Not stated
CD13+ ­CD29+ ­CD44+ ­CD49+ ­CD49b+ ­CD73+­CD90+ HLA-ABC+ ­CD9− ­CD14− ­CD31−­CD34− ­CD40− ­CD45− ­CD54− ­CD117−­CD133− HLA-DR−

Human subcutaneous adipose tissue of
18–30 years old mothers receiving cesar‑
ean sections

Human umbilical cord of healthy donor

Human umbilical cords of 18–30 years oldmothers receiving cesarean section

Human umbilical cord Wharton’s jelly

Human umbilical cord Wharton’s jelly

Human umbilical cord Wharton’s jelly

Human endometrium of women withuterine fibroids

Decreased migration capacity

Decreased tumor cell growth and increased
apoptosis

No effect on AC-A549

Decreased cancer cell proliferation

Decreased cancer cell proliferation and migra‑
tion capacity

Decreased cancer cell proliferation

CD29+ ­CD73+ ­CD90+ ­CD105+ ­CD166+ ­CD14− Decreased tumor tumorigenicity and EMT­CD31− ­CD34− ­CD45−

Not explored

Engineered IFNβ-expressing MSCs

Secretome has no effect on AC-A549

MSC-CM and in vivo co-transplantation

Increased apoptosis; G0/G1 cell cycle arrest
Upregulation of caspase-3 and caspase-9 anddownregulation of survivin and XIAPCell cycle arrest; induced apoptosis; down‑
regulated Bcl-2, pro-caspase-7, β-catenin
and c-Myc

Increased apoptosis; G0/G1 cell cycle arrest
Upregulation of caspase-3 and caspase-9 anddownregulation of survivin and XIAPMSCs-secreted OSM activates OSM/STAT1
signaling pathway

Enhanced tropism of MSCs towards tumor site Engineered CXCR1- overexpressing MSCs

Increased tumor cell apoptosis

Enhanced tropism of MSCs towards tumor site Engineered CXCR4- overexpressing MSCs

Decreased tumor growth and angiogenesis;
increased the survival of glioma-bearing
mice and tumor-specific long-term T-cell
immunity

Decreased tumor growth and angiogenesis

Decreased tumor growth and increased tumor TRAIL signalingcell apoptosis

Decreased tumor growth and increased
apoptosis

EffectHuman bone marrow of healthy donor

Lung cancer

CD29+ ­CD81+

Surface marker

Human umbilical cord blood of healthy
donorsCancer type/MSC source

Table 5 (continued)

[191]

[202]

[291]

[161]

[170]

[175]

[170]

[191]

[196]

[197]

[196]

[199]

[174]

[148]

[173]

Ref.

Zhuang et al. J Biomed Sci(2021) 28:28
Page 18 of 38

CD29+ ­CD44+ ­CD73+ ­CD90+ ­CD105+ ­CD14−­CD34− ­CD45− HLA-DR−
Not stated

Human umbilical cord of healthy donor

Human umbilical cord Wharton’s jelly

CD13+ ­CD44+ ­CD90+ ­CD105+ ­CD14− ­CD34−­CD45−

Human umbilical cords of 18–30 years oldmothers receiving cesarean section

Human bone marrow

CD105+ ­CD90+ ­CD44+ ­CD73+ ­CD45− ­CD34−­CD24− HLA-DR− ­CD14−

CD29 + CD44 + CD90 + CD105 +Human adipose tissue from liposuction

Ovarian cancer

CD13+ ­CD44+ ­CD90+ ­CD105+ ­CD14− ­CD34−
CD45-

Increased tumor cell apoptosis

Decreased cancer cell proliferation

Decreased tumor growth

Decreased cancer cell proliferation

[192]

Ref.

Engineered AFP promoter driving-sTRAILexpressing MSCs

Cell cycle arrest; induced apoptosis; down‑
regulated Bcl-2, pro-caspase-7, β-catenin
and c-Myc

Induced apoptosis and cell cycle arrest; Bcl-2,
c-Myc, PCNA and survivin were downregu‑
lated

Decreased NF-κB expression and activity

MSCs-CM induced reduction in the level of
CA-125, LDH and beta-hCG and expressionof MMP-2, MMP-9, and CA-125 as well as
increased TIMP 1, 2, and 3 mRNA expression

Increased apoptosis; G0/G1 cell cycle arrest
Upregulation of caspase-3 and caspase-9 anddownregulation of survivin and XIAPEngineered CD-expressing MSCs sensitizedcolon cancer cells to 5-FC

Increased apoptosis; G0/G1 cell cycle arrest
Upregulation of caspase-3 and caspase-9 anddownregulation of survivin and XIAPEngineered IL-15- expressing MSCs mediate
NK and CD8-positive T cells accumulation intumor site

[177]

[170]

[212]

[170]

[211]

[190]

[208]

[175]

[176]

[192]

Engineered IFNβ-expressing MSCs induced[203]
cell cycle arrest and increasing expression of
p21, p27 and FOXO3a as well as decreasingprotein levels of cyclin D1, pRb and AKT

Decreased NF-κB expression and activity

Factors/mechanisms

Decreased tumor growth and cell proliferation MSC-CM inhibits Wnt/β-catenin signaling
pathway by GSK-3β

Decreased tumor growth

Decreased cancer cell proliferation and migra‑
tion capacity

Decreased cancer cell proliferation

CD44+ ­CD29+ HLA-I+ ­CD34− ­CD38− HLA-DR− Decreased tumor growth and prolonged
survival of tumor-bearing mice

Human subcutaneous adipose tissue of
18–30 years old mothers receiving cesarean
sections

Colorectal cancer

Human umbilical cord blood of healthy
donors

Pancreatic cancer

Human umbilical cord of healthy donors
CD29+ ­CD44+ ­CD105+ ­CD34− ­CD45−

CD29+ ­CD44+ ­CD105+ ­CD166+ ­CD31− ­CD34− Decreased tumor growth­CD45− HLA-DR− ­vWF−

Human fetal dermal tissues at 4 months
gestation from abortion (Z3)Bile duct cancer

CD105+ ­CD166+ ­CD34−

Human fetal dermal tissues at 4 months
gestation from abortion (Z3)

Decreased tumor growth

CD44 + CD90 + CD34- CD45-

Human bone marrow of healthy donor

Decreased cancer cell proliferation

Effect

CD105+ ­CD166+ ­CD34−

Surface marker

Human fetal bone marrow at 4 months ofgestation from abortion (BMMS-03)

Liver cancer

Cancer type/MSC source

Table 5 (continued)

Zhuang et al. J Biomed Sci(2021) 28:28
Page 19 of 38

Not statedCD105+ ­CD90+ ­CD44+ ­CD73+ ­CD45− ­CD34−­CD24− HLA-DR− ­CD14−

Human umbilical cord Wharton’s jelly

Human umbilical cord Wharton’s jelly
Increased tumor cell apoptosis

Decreased tumor cells proliferation

Decreased tumor cells expression of CSC
markers; increased cell cycle arrest andapoptosis

Decreased tumor cells proliferation

Not stated

CD13+ ­CD29+ ­CD44+ ­CD73+ ­CD90+ ­CD105+­CD166+ ­CD14− ­CD31−CD45−
Not stated
CD73+ ­CD90+ ­CD105+ ­CD45− ­CD14−
Not stated

Resident MSCs of vascular wall

Human adipose tissue from normal (nondiabetic) adult lipoaspiration

Human adipose tissue of individuals receiv‑
ing mammoplasty

Human umbilical cord of healthy donors

Human umbilical cord Wharton’s jelly ofhealthy donor

Breast cancer

Decreased tumor cell growth and migration

Increased tumor cells apoptosis

Decreased tumor cell growth and lungmetastasis

Decreased tumor cell viability and migration

Decreased the risk of lung metastasis afterradiation-induced injury

Decreased tumor growth and pro-angioge‑
netic ability

CD44+ ­CD90+ ­CD105+ ­CD73+ ­CD29+ ­CD34−­CD45−

Human umbilical cord Wharton’s jelly

CD73+ ­CD90+ ­CD34−

CD73+ ­CD90+ ­CD105+
CD34− ­CD45− ­CD14− ­CD20−

Human umbilical cord Wharton’s jelly

Decreased tumor cell growth and migration

Human endometrium of healthy womenNot stated

Human umbilical cord Wharton’s jelly ofhealthy donor

Increased tumor cell apoptosis

Decreased tumor growth and prolonged
survival of tumor-bearing miceCD105+ ­CD90+ ­CD44+ ­CD73+ ­CD45− ­CD34−­CD24− HLA-DR− ­CD14−

Human adipose tissue from liposuction

EffectHuman umbilical cord blood of healthy
donors

Surface marker

Cancer type/MSC source

Table 5 (continued)

[292]

[167]

[177]

Ref.

[293]

[210]

[177]

hWJSC-CL and hWJSC-CM induced apoptosis
Upregulation of pro-apoptotic BAX anddownregulation of anti-apoptotic BCL2 andSURVIVIN genes

MSCs secretome

Not explored

MSC-secreted conditioned medium inhibits
canonical Wnt signalling

Downregulation of radiation-induced expres‑sion of endothelial MMP2 and of the SASP
factors CCL2 and Plau/uPA

[167]

[295]

[294]

[189]

[193]

Inhibition of AKT phosphorylation and[186]
decreasing the expressions of VEGFA and
HIF-1α in cancer cells, probably by activationof FoxO3a in cancer cells

Engineered IL-21-secreting MSCs

MSCs-CM induced reduction in the level of
CA-125, LDH and beta-hCG and MMP-2,
MMP-9, and CA-125 mRNA expression as
well as increased TIMP 1, 2,
and 3 mRNA expression

Not explored

MSC-CM and MSC-CL decreased expression of [178]cell cycle regulatory genes (cyclin A2, CyclinE1), prostaglandin receptor signaling genes(EP2, EP4) and the pro-inflammatory genes(IL-6, TNF-α) in cancer cells

MSC-CM and MSC-CL decreased the expres‑sion of oncogenic cytokines, chemokinesand growth factors in cancer cells

hWJSC-CL and hWJSC-CM induced apoptosis
Upregulation of pro-apoptotic BAX anddownregulation of anti-apoptotic BCL2 andSURVIVIN genes

MSCs-CM induced reduction in the level of
CA-125, LDH and beta-hCG and expressionof MMP-2, MMP-9, and CA-125 as well as
increased TIMP 1, 2, and 3 mRNA expression

Factors/mechanisms

Zhuang et al. J Biomed Sci(2021) 28:28
Page 20 of 38

Not stated
Not stated

Human umbilical cord blood of healthy
donors

Not stated

Resident MSCs of vascular wall

Human umbilical cord Wharton’s jelly ofhealthy donor

Bladder cancer

Human umbilical cord Wharton’s jelly ofhealthy donor

Esophageal cancer

Human umbilical cord blood

Not stated

CD73+ ­CD90+ ­CD105+ ­CD44+ ­CD45− ­CD14−­CD34−

CD44+ ­CD105+ ­CD29+ ­CD90+
CD38− ­CD117− ­CD45− ­CD34−

CD44+ ­CD90+ ­CD105+ ­CD34−

Human umbilical cord Wharton’s jelly ofhealthy donor

Gastric cancer

Not stated

Human umbilical cord Wharton’s jelly ofhealthy donor

Bone cancer

Not stated

Human bone marrow of healthy donor

Melanoma

Not stated−

Human umbilical cord blood of healthy
donors−

Mouse umbilical cord Wharton’s jelly+

CD44+ ­CD90+ ­CD105+ ­CD34−+

Human umbilical cord Wharton’s jelly ofhealthy donor+

CD73 ­CD90 ­CD105 ­CD44 ­CD45 ­CD14­CD34−+

Surface marker

Human umbilical cord Wharton’s jelly ofhealthy donor

Cancer type/MSC source

Table 5 (continued)

Decreased tumor growth

Increased tumor cells apoptosis

Increased tumor cell apoptosis

Decreased tumor cell growth

Decreased tumor cell growth and migration

Decreased the risk of lung metastasis afterradiation-induced injury

Decreased the risk of lung metastasis afterradiation-induced injury

Decreased tumor cell growth and lungmetastasis

Decreased tumor cell proliferation

Decreased tumor cell growth

Decreased tumor cell growth

Increased tumor cells apoptosis

Effect

Ref.

[179]

[167]

[193]

[193]

[294]

[296]

[169]

[179]

MSC-MVs induced down-regulated phospho‑rylation of Akt protein kinase and up-regu‑
lated cleaved Caspase 3

Upregulate p21 downregulate PCNA, cyclin
D1, Bcl-2, Bcl-xL, and MMPs and upregulate
p53 and p21

[180]

[168]

Engineered TNFSF14-secreting MSCs promote [209]tumor cell apoptosis with elevated cas‑pase-3 expression

MSC-CL and MSC-CM induced apoptosis andautophagy

MSC-CL and MSC-CM induced apoptosis andautophagy; upregulation of pro-apoptotic
BAX and autophagy genes (ATG5, ATG7, and
BECLIN1); downregulation of anti-apoptotic
BCL2, SURVIVIN genes

Downregulation of radiation-induced expres‑sion of endothelial MMP2 and of the SASP
factors CCL2 and Plau/uPA

Downregulation of radiation-induced expres‑sion of endothelial MMP2 and of the SASP
factors CCL2 and Plau/uPA

Not explored

MSC-ECM

Increased activated caspase-3

Intra-tumoral injections of MSC-CM and MSC

Upregulating p21[168]
Downregulating PCNA, cyclin D1, Bcl-2, Bcl-xL,
and MMPs and upregulating p53 and p21

Factors/mechanisms

Zhuang et al. J Biomed Sci(2021) 28:28
Page 21 of 38

CD73+ ­CD90+ ­CD105+ ­CD45−
CD73 CD90 CD105 CD14 CD19 CD34 CD45
and HLA-DR
Not stated
Not statedCD105+ ­CD73+ ­CD90+ ­CD45− ­CD34− ­CD14−­CD11b− CD79α−/ ­CD19−
Not statedCD105+ ­CD73+ ­CD90+ ­CD34− ­CD45−
Not stated

Human umbilical cord of healthy donor

Human umbilical cord of healthy donor

Human umbilical cord of healthy donor

Human umbilical cord Wharton’s jelly ofhealthy donor

Human umbilical cord Wharton’s jelly ofhealthy donor

Human umbilical cord Wharton’s jelly ofhealthy donor

Human umbilical cord Wharton’s jelly ofhealthy donor

Human umbilical cord blood of healthy
donor

Engineered IDO -secreting MSCs abolish theanti-apoptotic effect of MSCs

Engineered Tandab -expressing MSCs com‑bined with IDO pathway inhibitor inhibit
expression of CD98 and Jumonji

Not explored

MSCs secreted IL-6 activates MEK/ERK path‑ways

Not explored

Factors/mechanisms

Decreased tumor cell proliferation

Decreased tumor cell proliferation

Decreased cell viability and mitochondrial
membrane potential; increased apoptosis

Decreased tumor cells viability; increased
tumor cells apoptosis

Direct cell-to-cell contact caused arrest of thegrowth of cancer cells in the G0/G1 phase

IFNγ stimulated MSC secretome

MSC-CM-3 kDa MWCO regulates cellular ­H2O2
levels

MSC-CM induced CD47 and PD-L1 expression
decreased in the tumor cells

Decreased tumor growth and increased tumor Engineered scFvCD20-sTRAIL fusion protein
cell apoptosis-secreting MSCs

Decreased tumor cell proliferation

Decreased tumor growth

Decreased tumor cell clonogenicity andgrowthCD13+ ­CD29+ ­CD44+ ­CD73+ ­CD90+ ­CD105+ Inducing granulocytic differentiation­CD166+ HLA-ABC+of APL cells
CD14− ­CD31− ­CD34− ­CD38− ­CD45− HLA-DR−

Human umbilical cord of healthy donor

Decreased tumor cell clonogenicity andgrowthEffectCD73+ ­CD90+ ­CD105+ ­CD45−

Surface marker

Human adipose tissue from 3liposuction

Hematological cancer

Cancer type/MSC source

Table 5 (continued)

[183]

[298]

[182]

[181]

[207]

[206]

[205]

[297]

[194]

[297]

Ref.

Zhuang et al. J Biomed Sci(2021) 28:28
Page 22 of 38

Zhuang et al. J Biomed Sci(2021) 28:28

Page 23 of 38

Fig. 4 Schematic diagram of tumor suppressing mechanisms of MSCs. MSCs suppress tumor progression predominantly by promoting tumor cell
apoptosis, autophagy, and senescence; and by boosting immunity, anti-angiogenesis, and anti-tumor cell migration and invasion

shown to prolong animal survival [200, 201]. Meanwhile,
IFN-beta-WJMSCs and IFN-beta-hBMMSCs exhibitedthe ability to suppress tumor growth in bronchioloalveolar carcinomas [202] and HCCs, respectively, thelatter exerting its effect by increasing expression of p21,
p27 and FOXO3a, as well as decreasing protein levels of
cyclin D1, pRb and AKT [203]. In addition, engineered
BMP4-secreting hADMSCs could suppress tumor cell
migratory ability and increase survival in glioblastoma[204]. As for hematological cancers, treatment with hUCMSCs equipped with Tandab (a tetravalent bispecifictandem diabody with two binding sites for CD3 and two
for CD19) combined with IDO pathway inhibitor showedsignificantly decreased B cell lymphoma growth by way of
decreasing CD98 and Jumonji, and by restoring the proliferation of T cells [205]. Another study demonstrated
that UC-MSCs overexpressing IDO can inhibit proliferation of leukemia cells [206]. hWJMSCs engineered
with scFvCD20-sTRAIL fusion protein, which targets
CD20-positive cells and induces apoptosis throughsTRAIL, inhibited proliferation in B cell lymphoma [207].
Another study showed that hWJMSCs transfected with
vector coding sTRAIL driven by AFP promoter had significant antitumor activity in HCC [208]. Decreased
tumor growth was also observed in gastric cancer andin epithelial ovarian cancer using hUCBMSCs delivering TNFSF14 or IL-21, respectively [209, 210]. In a syngeneic pancreatic tumor mouse model, IL15-hUCBMSCs
inhibited tumor growth and increased survival of tumorbearing mice. The IL15-hUCBMSCs induced NK- andT-cell accumulation at the tumor site and establishedtumor-specific T-cell memory immunity [211]. Cytosine
deaminase-expressing hADMSCs serving as a prodrug
converting vehicle, showed significant decreases in colorectal cancer growth in the presence of prodrug 5-fluorocytosine [212].
Summary of promotion and suppression effects of MSCs
in cancer

MSCs can contribute to tumor promotion as well as totumor suppression. Although it may appear that theseeffects occur randomly, closer examination provides
a more promising picture. Summarizing a total of 110
reports, (excluding engineered MSCs) reveals that in
58.6% of the studies, BMMSCs promoted tumor growth,
while 9.8% of studies found that BMMSCs suppressed
growth. Although the tendency of ADMSCs is not as
obvious as that of BMMSCs, they also exhibit a preference for tumor promotion (Fig. 2). In general, MSCs
derived from reproduction-related sources, including
placenta, umbilical cord, Wharton’s jelly, and umbilical cord blood, show a higher likelihood for tumor suppression (Fig. 2). In regards to tumor type, we found that
BMMSCs show an overwhelming promoting effect on
cancers of the bone (100%, 6/6), breast (100%, 7/7) andGI tract, (liver, bile duct, colorectal, gastric and esophageal; 93.75%, 15/16) (Fig. 2a).
MSCs demonstrate an impressive suppressive ability inhematological cancers. In all 7 studies, MSCs from different tissue types showed tumor suppression. Similarly,
in a total of 8 studies of MSCs and ovarian cancer, only
one study reported that MSCs promoted tumor growthZhuang et al. J Biomed Sci(2021) 28:28(Fig. 2b). To date, there is no report showing a tumor
promoting effect for MSCs from placental tissue.
MSCs can exert their effects directly by contacting
tumor cells, or indirectly by secreting soluble factors andmicroRNAs that the affect the tumor cells. The mechanisms by which different types of MSCs promote or suppress the growth of different tumor types are complicated(Tables 2, 3, 5, Fig. 4). Factors that may affect the properties of MSCs and cause different outcomes, include (1)the origin of the MSCs; (2) different processes of isolation, purification, and expansion of MSCs; and (3) different culture conditions and passages of the MSCs. Mostof the results described herein were derived from direct
or indirect in vitro co-culture systems or from in vivo
co-injection experiments, but the underlying mechanisms were not always examined. It will be necessary
to elucidate these underlying mechanisms, as well as tofind potential biomarkers of MSC-tumor interactions for
future clinical applications of MSCs.
Biodistribution of therapeutic cells in a preclinicalevaluation

In light of the tremendous potential of MSCs for treating
various diseases, it is necessary to define the systemic distribution and to quantify the administered cells in orderto facilitate our understanding of the safety and efficacyof MSC-based cell therapy. This information is critical in clinical trials since it is vitally important to knowwhether the transplanted cell products home to the target diseased sites to deliver their intended effects. Indeed,
several factors can affect the pharmacokinetics (PK) of
the administered MSCs, including cell size, cell source,
immunological features and labeling, detection methods,
route of administration, and size of the animal model.
Factors that affect the biodistribution of MSCs

The typical diameter of a MSC is between 15–30 μm;
in comparison, lymphocytes have a diameter of only
4–12 μm [213]. Furthermore, MSCs become larger
after serial ex vivo cell passaging [214]. The relatively
large size of MSCs explains their initial mechanicalentrapment at lung capillary systems after intravenous
administration, a phenomenon referred to as the pulmonary first-pass effect [26, 215]. Redistribution toliver, spleen, and other inflamed tissues subsequently
takes place in the following hours to days, with gradualclearance from the lungs [26]. In some studies, MSCs
were still detected in the lungs up to 150 days after
transplantation in vivo [216]. MSCs retained at thelungs potentially decrease the number of cells available
for therapeutic effects [217]. To decrease the mechanical entrapment of MSCs at the lungs, several strategies
may be implemented, including pretreatment with thePage 24 of 38

vasodilator sodium nitroprusside in order to increase
the effective diameter of the pulmonary capillary system; delivery via an extravascular route; or delivery
via multiple smaller doses [215, 217, 218]. Althoughadministering MSCs intra-arterially may decrease theextent of mechanical entrapment at the lungs [219],
the effect of cell size still has important implications,as larger MSCs may be associated with vascular occlusions that could cause subsequent ischemia and infarcts
of unintended tissues and organs [220, 221]. Engineering of MSCs might potentially alter this adverse effect.
For example, by overexpressing integrin α4 (ITGA4),
which mediates leukocyte trafficking of MSCs, Cuiet al. observed that cell aggregation of MSCs were significantly decreased, and MSC-associated cerebral
embolism was ameliorated in rat model of stroke [222].
Furthermore, the risk of embolism has been found to
be positively associated with cell dose of infusion andlow infusion velocity [223].
In addition, aging of either donor or recipient could
affect the biodistribution of inoculated MSCs, withdecreased transplantation efficiency observed with aged
donor MSCs and recipients [224]. Furthermore, when
MSCs were extracted from older donors, they exhibited
lower proliferative and differentiation capabilities [225,226]. The culture condition also plays a role in the kinetics of administered MSCs. For example, hypoxic preconditioning increased MSC migration to injured tissue via
enhanced HGF/cMET signaling and MSC recruitment,
thus affecting biodistribution of the administered cells[227].
Immunogenic reactions also affect clearance and biodistribution of injected cells, as the allogeneic MSCs are
not completely immune-privileged [228]. When MSCs
are transplanted in an allogeneic host, the transplanted
MSCs have decreased survival compared with their survival in a syngeneic host [229]. Formation of antibodies
against injected MSCs could explain the reduced effectiveness and increased adverse effects that were observedwith repeated inoculations in some studies [230].
Furthermore, the injected cells can also trigger an
instant blood-mediated inflammatory reaction (IBMIR),
which causes reduced graft survival and thromboembolism [231]. A portion of injected MSCs do not reach theirintended destination due to the host’s immune reaction,
embolization, and micro-ischemia [232]. Previous literature has demonstrated that the extent of IBMIR is related
to the level of tissue factor (TF) expressed by MSCs;
expression levels vary among different tissue origins ofMSCs, and with culture conditions [233]. Compared with
ADMSCs and UCMSCs, BMMSCs express lower levelsof TF [233]. Thus, selecting TF-deficient BMMSCs may
reduce the risk of IBMIR and improve the chances forZhuang et al. J Biomed Sci(2021) 28:28

Page 25 of 38

Table 6 Comparison of methods used for quantitative mesenchymal stem/stromal cells (MSC) detection (Adapted from ref. [300])
Technique

Detection

Advantages

Disadvantages

PCR/histology

Transplanted-cell specific DNA
sequences or antigens

High sensitivity
No need to label the cells

Need animal sacrifice, biopsy,
Postmortem samples from patients

Optical imaging

Fluorescent dyes/proteins

High throughput
Good for longitudinal studies

Small animals only,
Low resolution,
Non-stable

Flow cytometry

Fluorescent dyes/proteins

High specificity,
Quantification of live cells

Preclinical use only

MRI

Contrast agents

Clinically usefulHigh spatial resolution
Whole-body scanning

Quantification is difficult
Cytotoxicity of certain labeling agentsRadionuclear

Radioisotope labels

Quantification feasible using SPECT
Whole-body scanningHigh sensitivity

Limited spatial resolution
Ionizing radiation

FND

Fluorescence

Large animal models (pigs)
PK/PD of transplanted cells
Biodistribution of transplanted cells
Background-free imaging
Single-cell detection sensitivity
High throughput quantification
No interference with cell potency

Need animal sacrifice

PCR polymerase chain reaction, PET positron emission tomography, SPECT single-photon emission computed tomography, FND fluorescent nanodiamond, PK
pharmacokinetic, PD pharmacodynamics

clinical success. Otherwise, co-treatment with an anticoagulant may be an important consideration for clinicalapplications [234].
Methods of tracking MSCs in vivo

A critical step in generating pharmacokinetic models ofcell products is tracking the fate of cells following transplantation. An ideal quantification technique should havethe following features: high sensitivity and specificity;
long-term detection and monitoring; and spatiotemporal resolution. The advantages and disadvantages of currently available methods for quantitative MSC detection
are summarized in Table 6. Polymerase chain reaction(PCR) has been used to track human MSCs in murine
xenogeneic models by detecting human DNA [19, 235–
237]. The low limit of detection of quantitative PCR enables detection of 100 MSCs per gram of organ tissue,
making it feasible to detect MSCs in patient biopsies.
Both flow cytometry and optical imaging require labeling
MSCs with fluorescent dyes or proteins. Flow cytometry enables estimation of the number of live MSCs perweight unit of tissue, and optical imaging uses a variety
of dyes, such as 4′,6-diamidino-2-phenlindole (DAPI),
that can bind reversibly or irreversibly to the MSCs
[238–241]. The use of red fluorescent protein (RFP) or
green fluorescent protein (GFP) expressing MSCs has
the advantage of providing viability information of transplanted cells [242]. However, the transfection efficiency
is not consistent, and the transfected cells could havealtered potency and expression and cannot be accurately

tracked over time [243]. Therefore, the biodistribution
and quantitative data produced by fluorescent proteinlabeling methods may be incomplete. Bioluminescenceimaging (BLI) which utilizes luciferase reactions also has
the advantage of providing viability information of transplanted cells, but this method suffers from poor tissue
penetration and low spatial resolution. MSCs can also
be labeled with gold nanoparticle and tracked by computed tomography (CT) image in vivo [244, 245]. These
gold nanoparticles have advantage of exerting negligible
influence on viability, proliferation, and differentiation
ability of labeled MSCs, and offer good spatial resolution
and long-term tracking when used in conjunction with
CT modality [244]. However, sensitivity is relatively poor,and there is still difficulty deriving quantitative information from CT images [246].
Magnetic resonance imaging (MRI) can be used to
track MSCs in vivo by labeling MSCs with superparamagnetic iron oxide nanoparticles (SPIONs) or fluorine-19 (19F). Direct labeling of MSCs with SPIONs is
possible as these agents are readily taken up by MSCs
and show up as hypointense signals on MRI [247]. However, some studies have shown that proliferative and differentiation capabilities of MSCs could be affected whenlabeled at higher concentrations [247]. The downside of
SPION labeling is that the specificity of SPION-labeledcells could be low and the signals could be hard to differentiate from acutely injured tissues containing hemorrhages. In contrast, 19F-labeling offers better specificity as
endogenous fluorine level is low, minimizing backgroundZhuang et al. J Biomed Sci(2021) 28:28

interference and is a better labeling agent when the targeting lesion involves hemorrhage [248]. In general,
MRI offers good spatial resolution but suffers from poor
temporal resolution. Positron emission tomography(PET), single-photon emission computed tomography(SPECT) [26, 249–251] and radioisotope labeling [26,252, 253] have been used to image and track the migration dynamics, and inter-patient variability of MSCs inclinical patients, but quantifying cell numbers with thesemethods is difficult and only semi-quantitative information on the biodistribution of the transplanted cells
can be obtained. Photoacoustic imaging, which combines ultrasonography with optical imaging, is anotherattractive approach, as ultrasonography has the uniqueadvantage of providing real-time information whilestill maintaining good spatial resolution. By using gold
nanorods coated with reactive oxygen species (ROS) sensitive dye as probe, Dhada et al. were able to also detectviability of implanted cells [254]. However, photoacoustic imaging suffers from operator dependent variability[255]. More recently, multimodal imaging probes thatcombine the advantage of different imaging modalities
have been developed, including PET/MRI imaging agent[256], SPECT/MRI/fluorescent imaging agent [257], and
SPECT/MRI/BLI imaging agent [258].
An ideal cell tracking method should be biocompatible and nontoxic, require no genetic modification, havesingle-cell detection sensitivity, and permit quantification of cell numbers at any anatomic location. Opticalimaging utilizing nanoparticles as exogenous contrast
agents is suitable for this purpose, although the technique is mainly used for animal models in preclinicalexperimentation due to the limited penetration depthof visible photons into tissue. Among various exogenous
contrast agents, fluorescent nanodiamond (FND) has
emerged as an attractive option because it is chemicallyinert and inherently biocompatible [259, 260]. A viableapplication of FNDs for background-free imaging andquantitative tracking of MSCs in animal models beyond
rodents has been demonstrated using magnetic modulation [261–263]. The magnetic modulation fluorescence(MMF) method uses magnets to modulate the fluorescence intensity of FNDs. This technique, which allows
background-free imaging, together with the inertness of
FNDs and the large quantity of the nanoparticles taken
up by the cells, has permitted studies of the biodistribution and pharmacokinetics of FND-labeled MSCs inpreclinical settings. This strategy can also be applied tothe characterization of cell-based products in order toaccelerate their progression towards commercialization
to meet the needs of patients. The technique has excellent compatibility with time-gated fluorescence imaging, which has been shown to be a powerful means ofPage 26 of 38

acquiring high-contrast fluorescence imaging of FNDlabeled cells in tissues. The ability to find single cells isparticularly valuable for ex vivo histological detection of
MSCs in clinical trials. This combined approach represents an appealing alternative to hazardous radioisotope
labeling techniques in cell tracking applications. The
technique can be used with immune cells, stem cells, andother cell types used for cell therapy. Here, we put thesetechnologies together, and describe how they could be
used to contribute to the development of pharmacokinetic modeling of MSC-based cell products.
An FND‑based platform to track therapeutic cells in vivo

The ability to monitor the behavior of transplanted cells
in vivo is required for cell therapy. When cellular products are submitted for investigational new drug (IND)
status, pharmaceutical studies must provide evidenceof not only the safety of the cell product, but also information regarding cell location, cell migration, PK andpharmacodynamics (PD), and cell biodistribution after
transplantation in animal models. There are three critical issues that must be addressed for cell therapy: (1)whether therapeutic cells maintain their potency after
transplantation, (2) the appropriate dosage for curing
diseases and (3) a route of administration and a formulation that permits successful drug delivery. Over the
past decade, the traditional concepts, confined to low
molecular weight organic compounds and large biomolecules, have been challenged with the advent of new drugs
based upon cells, which we refer to here as cell therapy.
As for all drugs, understanding the pharmacology ofcell-therapy products is critical for their effective application in the clinical setting. For example, tissue section
and PCR does not provide sufficient information of cell
behavior in vivo, because these procedures select a sample from a population, making it difficult to provide PK
and PD information for the whole animal. In contrast, theFND-labelled tracking technique provides a new method
to achieve high throughput whole organ treatment andanalysis, providing accurate pharmacology information,such as PK, PD and biodistribution of the cellular therapy (Fig. 5a). This method not only provides immediateand highly specific cell localization data after gatheringhistological sections from the animal, but also provides a
one-step, one-tube analysis for any kind of animal tissue.
Compared to the qPCR sampling method, this protocol
can provide more accurate data for whole organ/tissue
analysis and takes less time for validation and analysis.
We use a healthy mouse model to demonstrate that
the FND-labelled platform can provide evidence ofcell biodistribution. Figure 5b shows the biodistribution analysis of FND-labelled placenta choriodecidual
membrane-derived MSCs (pcMSCs) for one week in aZhuang et al. J Biomed Sci(2021) 28:28

Page 27 of 38

Fig. 5 Workflow of fluorescent nanodiamond (FND)-labelled tracking platform and biodistribution analysis of FND-labelled pcMSCs. a The
FND-labelled tracking platform for cell biodistribution analysis. This platform can provide analysis for transplanted cell localization, pharmacokinetics(PK), and pharmacodynamics (PD). FND-labelled cells are delivered through intravenous injection. The transplanted cells can be pinpointed to
specific locations with background-free imaging by Leica SP8 microscopy using a time-gating technique. PK and PD analyses can be performed
with a magnetic modulation fluorescence (MMF) machine after tissue/organ digestion. b Distribution of FND-labelled pcMSCs among different
organs in a healthy mouse model. Experiments were repeated in triplicate and error bars represent the standard deviation

mouse model using the FND-based labelling platform.
Our results show that the majority (up to 70%) of FNDlabelled pcMSCs localized to the lungs after intravenous administration, which is consistent with thepulmonary first-pass effect [217, 264]. The trapping of
MSCs in the lungs is due to space restriction [265], as

pcMSCs are more than ~ 20 μm in diameter and muchlarger than the width of the micro-capillaries of thelung. After intravenous infusion, FND-labelled pcMSCs disappeared from the lungs as time passed, andmigrated to other tissues/organs such as the liver andspleen, or to injured sites. Nevertheless, the number ofZhuang et al. J Biomed Sci(2021) 28:28

Page 28 of 38

Fig. 6 Fluorescent nanodimond (FND)-labelled pcMSC biodistribution analysis in mouse model with a kidney ischemia–reperfusion injury. aTimeline of the ischemia–reperfusion kidney injury mouse model. The ischemia–reperfusion injury was created on the left-hand side kidney (L) in amouse, then FND-labelled pcMSCs were injected through the portal vein. b Bodistribution of FND-labelled pcMSCs in healthy kidney mouse model.
Experiments were repeated in triplicate and error bars represent the standard deviation of the measurements. c Biodistribution of FND-labelled
pcMSCs in ischemia–reperfusion kidney injury mouse model. Experiments were repeated in triplicate and error bars represent the standard
deviation of uncertainty. Data are presented as mean ± standard deviation. Data were analyzed using Student’s t-test. *P value of < 0.05. **P valueof < 0.01. ***P value of < 0.001. ****P value of < 0.0001

FND-labelled pcMSCs decreased in the heart and kidneys (Fig. 5b).
As it has been reported that MSCs will migrate to
injured sites [266], we induced an ischemia–reperfusion
injury to the left kidney in our animal model (Fig. 6a)and examined whether FND-labelled pcMSCs injected

into the portal vein would appear in the injured kidney, to test the concept that MSCs will migrate to sites
of injury. In our mouse model with healthy kidneys, thenumber of pcMSCs in the kidneys decreased over time
(Fig. 6b, upper panel) and the decrease was evident inboth the left and right kidneys. (Fig. 6b, lower panel). In

Zhuang et al. J Biomed Sci(2021) 28:28

contrast, in the mouse model with the injury the number of FND-labelled pcMSCs in the injured kidney was
highest on day 5 (3%; Fig. 6c). As seen in the lower panelof Fig. 6c, the injured kidney (L kidney) had significantly
more FND-labelled pcMSCs than the healthy kidney (Rkidney). The percent of FND-labelled pcMSCs remained
consistent over time (~ 0.25%) in the healthy right kidney(R kidney) (*P < 0.5, **P < 0.01, ***P < 0.001, ****P < 0.0001.)(Fig. 6c, lower panel). Given these data, it appears thatthe percentage of MSCs that migrate to kidneys is limited
to about 4%, and it appears that the kidneys have the ability to redistribute MSCs in vivo. In addition to providing
fast and accurate results, this technique is completely
safe to the cell tissue. The FND-labelling technique does
not alter any properties of the cell, including cell viability, proliferation, differentiation and immunomodulation,
making this method very biocompatible.
Clinical applications of MSCs in cell therapy: safety
and potency

The potential and promise of MSC therapy is highly
anticipated in recent and coming decades. As with all
emerging new medical technologies, patient safety isalways the first priority. As we have discussed, although
the ability to modulate immune environment and promote tissue regeneration have been well reported in preclinical studies, the aspect regarding tumor induction or
promotion is still one of the many concerns. The MSCs
derived from different tissue origins or expanded under
different culture conditions present different immune
profiles which may result in tumor promotion [126].
Additionally, as the double sided blades of the MSCs’
strong immune modulation ability [262], evaluation ofboth the specific MSC properties as well as the patient’s
immune conditions is strongly needed. The patient’s
immune condition both before, during, and after treatment should be closely monitored.
Some reports showed that artificial engineering process may decrease the tumor induction and increase
tumor-suppressing function of MSCs [263]. However,genetically engineered MSCs also raise other safety concerns. Although several clinical trials claimed the safetyof MSC-treated patients, however, most of the trials only
showed short-term safety and are without the examination of tumor-associated biomarkers [267, 268].
A recent systematic review and meta-analysis reappraised 55 randomized controlled trials and over 2000
patients to investigate the safety of systemically inoculated MSCs [39]. The risk of fever was significantly
greater in the group of patients receiving MSCs. There
was no significant increase in the risk of infection,
thrombo-embolic events, malignancy or ectopic tissue
formation, while the risk of death was significantly lower

Page 29 of 38

in the MSC-treated patients. Among the included studies, severe adverse events, including treatment related
fever, in-stent thrombosis with death, acute coronary
artery occlusions after intra-coronary delivery, grade 1
anaphlyactoid reaction, gastric ulcer perforation, hypersensitivity reaction, and anal cancer, have been reported
to be possibly related to MSC treatment. Although
the conclusion of the meta-analysis ends on a promising note, it was also emphasized that an a priori plan tomonitor safety should be outlined in every clinical study
design, including immediate allergic reactions, local complications (hematoma formation, local infection), vascular obstructions (dyspnea, oliguria, myocardial infarction,
venous thromboembolic events), systemic complications(systemic infection, abnormal liver or renal function),malignancy or ectopic manifestation of implanted MSCs,
and other disease-specific safety considerations [39].
Additionally, patients with medical history of ischemic
diseases, cardiovascular diseases, lung fibrosis, concurrent neoplasm, and family history of hereditary cancer
should be carefully reviewed during MSC treatment.
The cell dose, infusion route and rate should be documented. The product profiles of the MSCs from different
tissues and different generation processes, such as transcriptome, epigenome, proteomic data, cell populations,potential potency biomarkers, preclinical data from celland animal studies, should be provided.
The therapeutic efficacy of MSCs in different disease
indication is still under evaluation, as most of the studies
to date have been limited to phase 1 and phase 2 studies(Fig. 1b and 1c, Additional file 2). As we have discussed
in this review, the differences in MSC tissue origins andthe variety of cell culture conditions would be some of
the important factors determining MSC potency in vivo[269]. Thus, the development of surrogate potency assays
using preclinical animal model is needed [270]. Recently
the International Society for Cellular Therapy (ISCT)
have announced some strategies to identify the potential
effective factors of MSC action mechanism, including the
combined the matrix assay and multiple techniques, suchas quantitative RNA analysis for the specific genes, flow
cytometry analysis for cell surface markers, and the protein-based assay of secretome [271]. Potency assessmentsin evaluating cell pharmacology, cell delivery route, as
well as the cell-drug interaction are still under development to improve the MSC precision therapy [272–275].
Although the matrix assays were reported to serve as aplatform to identify the biomarkers for MSC potency
in vitro [276, 277], whether this in vitro assays are able
to identify the MSC potency are still under discussion.
For example, the use of allogeneic human peripheral
blood mononuclear cells for mixed lymphocyte reaction (MLR) assays is a popular assay to demonstrate theZhuang et al. J Biomed Sci(2021) 28:28

MSC immunomodulation capacity. However, the lackof robustness, accuracy, and reproducibility is of concern [278–280]. Additionally, the correlation between
the in vitro assays and in vivo pre-clinical/clinical datarequires further evaluation.
Cryopreservation could be another factor affecting
MSC potency. It has been documented that the MSC
cryostorge, the so-called “cryo stun effect”, may decrease
MSC therapeutic efficacy, leading to failures in MSC
clinical trials [278]. Recently, a systematic review regarding the impact of cryopreservation on BMMSCs showedthat the cryopreservation appears to affect the cell viability, apoptosis, cellular attachment, immunomodulation, and metabolism of BMMSCs [279]. Furthermore,these impaired viability or functions of the MSCs canbe restored, partially or totally, by following an acclimation period [279–281], or by IFNγ licensing before cryopreservation [282].
In summary, the use of standardized potency assays
should be incorporated into future MSC product releasecriteria. Thus, development of surrogate potency assays
for different disease indications should be highlighted.
The optimal process of cryopreservation and thawing may be another important factor requiring further
attention.

Conclusions
MSCs are a major cornerstone to the advancement ofcell therapy, yet much remains to be learned about theirpharmacokinetics and pharmacodynamics after systemic
application in vivo. The different tissue origins of MSCs
not only confer different biological activities that affecttheir therapeutic usefulness, but also raise the concernof different safety profiles. Many methods, including
herein discussed fluorescent nanodiamond, are available
for tracking inoculated MSCs in vivo, each with different
advantages and disadvantages. These imaging platforms
will facilitate future studies to discern and optimize theuse of different MSCs for future clinical therapies.
Abbreviations
AC-LCSC: Adenocarcinomas-lung cancer stem cells; AFP: Alpha-fetoprotein;
ALDH: Aldehyde dehydrogenase; ALP: Alkaline phosphatase; Ang-1: Angi‑
opoietin-1; APL: Acute promyelocytic leukemia; ATG5: Autophagy related 5;
ATG7: Autophagy related 7; BAX: Bcl-2-associated X; Bcl-2: B-cell lymphoma
2; Bcl-xL: B-cell lymphoma-extra large; BCRP: Breast cancer resistance protein;
BMP: Bone morphogenetic protein; CA-125: Cancer antigen 125; CAFs:
Cancer-associated fibroblasts; CCL2: C–C motif chemokine 2 (MCP-1); CCL5:
C–C motif chemokine 5; CCR1: C–C chemokine receptor type 1; CD: Cytosine
deaminase; CL: Cell lysate; CM: Conditioned medium; CSC: Cancer stem cells;
CTL: Cytotoxic T-cell; CXCL1: C-X-C Motif Chemokine Ligand 1 (GRO-a); CXCL8:C-X-C Motif Chemokine Ligand 8 (IL8); CXCL12: C-X-C Motif Chemokine
Ligand 12 (SDF-1); CXCR1: C-X-C chemokine receptor type 1; CXCR2: C-X-C
chemokine receptor type 2; CXCR4: C-X-C chemokine receptor type 4; CXCR7:C-X-C chemokine receptor type 7; CXCR12: C-X-C chemokine receptor type
12; DIABLO: Direct IAP-Binding protein with Low PI; ECM: Extracellular matrix;

Page 30 of 38

EGFR: Epidermal growth factor receptor; EMT: Epithelial–mesenchymaltransition; EP: Prostaglandin E2 receptor; ERK: Extracellular signal–regulated
kinase; ET1: Endothelin-1; EVs: Extracellular vesicles; Exos: Exosomes; FAK: Focal
adhesion kinase; FND: Fluorescent nanodiamond; FoxO3a: Forkhead box class
O 3a; GBM: Glioblastoma Multiforme; Glut-1: Glucose transporter type 1; GROa: Growth-regulated oncogene-alpha (CXCL1); GSK3β: Glycogen synthasekinase 3β; hCG: Human chorionic gonadotropin; HDGF: Hepatoma-derived
growth factor; HGF: Hepatocyte growth factor; HIF-1α: Hypoxia-inducible fac‑
tor 1alpha; HK-2: Hexokinase-2; IBMIR: Instant blood-mediated inflammatory
reaction; IDO: Indoleamine-2,3-dioxygenase; IGF: Insulin-like growth factor;
IL1β: Interleukin 1 beta; IL6: Interleukin 6; IL8: Interleukin 8; IFN: Interferon; JAK:
Janus kinase; JNK: C-Jun N-terminal kinase; LDH: Lactic dehydrogenase; Mad1:
Mitotic arrest deficient 1; MAPK: Mitogen-activated protein kinase; MARCKS:
Myristoylated Alanine Rich Protein Kinase C Substrate; MCP-1: Monocyte
chemoattractant protein-1 (CCL2); MDSC: Myeloid-derived suppressor cells;
MMF: Magnetic modulation fluorescence; MMP: Matrix metalloproteinase;
MSC: Mesenchymal stem/stromal cell; MWCO: Molecular weight cut off; NRG1:
Neuregulin 1; NF-kB: Nuclear factor kappa-light-chain-enhancer of activated B
cells; NK: Natural killer; OSM: Oncostatin M; PAI-1: Plasminogen activator inhibi‑
tor-1; PCNA: Proliferating cell nuclear antigen; PDCD4: Programmed cell death
4; PDGF: Platelet-derived growth factor; PDGFR: Platelet-derived growth factor
receptor; PD-L1: Programmed death-ligand 1; PI3K: Phosphoinositide 3-kinase;
PD: Pharmacodynamics; PK: Pharmacokinetics; PKM-2: Pyruvate Kinase M2;
Plau/uPA: Urokinase-type plasminogen activator; pRb: Phosphorylated
retinoblastoma protein; PTBP1: Polypyrimidine tract-binding protein 1; PTEN:
Phosphatase and tensin homolog; RECK: Reversion-inducing-cysteine-richprotein with kazal motifs; SCC: Squamous cell carcinomas; SASP: Senescenceassociated secretory phenotype; SDF-1: Stromal cell-derived factor-1(CXCL12);
Sema-7A: Semaphorin-7A; Smac: Second mitochondria-derived activator of
caspases; STAT​: Signal transducer and activator of transcription; TAM: Tumorassociated macrophage; TF: Tissue factor; TGF-β: Transforming growth factor
beta; Th1: T-helper 1; TIMP: Tissue inhibitors of metalloproteinase; TMZ: Temo‑
zolomide; TNF-α: Tumor Necrosis Factor-α; TNFSF14: Tumor necrosis factor
superfamily member 14; TRAIL: Tumor necrosis factor-related apoptosis-induc‑ing ligand; VEGF: Vascular endothelial growth factor; XIAP: X-linked inhibitor of
apoptosis protein; ZEB1: Zinc finger E-box binding homeobox 1.

Supplementary Information
The online version contains supplementary material available at https://​doi.​
org/​10.​1186/​s12929-​021-​00725-7.
Additional file 1. Flowchart of MSC clinical study inclusion. As of October
11, 2020, 1,242 registered studies were identified on clinicaltrials.gov bysearching keywords “mesenchymal stem cell” or “mesenchymal stromalcell”. After excluding studies with no longer available/ suspended/ tem‑porarily not available/ terminated/ unknown/ withdrawn status, unknown
phase information, and studies that did not use MSCs in their intervention
arm, 639 studies remained. Nine of these 639 studies investigated MSCs
from two tissue origins, generating a total of 648 studies for analysis.
Additional file 2. Breakdown of MSC-related clinical studies by disease
indication. The included studies for analysis are as illustrated in Additional
file 1.
Acknowledgements
We thank Dr. Houng-Chi Liou of Department of Pharmacology, College ofMedicine of National Taiwan University for his excellent technical support withkidney ischemia/reperfusion animal model.
Authors’ contributions
Conception and design: WZZ, YHL, TYL and YHH; Development of method‑
ology: HCC, LJS, TYL; Acquisition of data (provided animals, acquired andmanaged patients, provided facilities, etc.): HCC, LJS, TYL, YHH; Analysis andinterpretation of data (e.g., statistical analysis, biostatistics, computational
analysis): WZZ, YHL, LJS, TYL and YHH; Writing, review, and/or revision of themanuscript: WZZ, YHL, HYJ, TYL and YHH; All authors read and approved thefinal manuscript.

Zhuang et al. J Biomed Sci(2021) 28:28

Funding
This study is supported by research grants from Ministry of Science andTechnology, Taiwan (Grant numbers: MOST 107-2321-B-038-002, MOST
107-2314-B-038-061, MOST108-2314-B-038-006, MOST108-2321-B-038-003,
MOST109-2314-B-038-135, MOST109-2321-B-038-003 to YHH; and MOST1052325-B-002-040, MOST106-3114-B-038-001, MOST107-2321-B-038 -002,
MOST108-2321-B-038-003 to TYL).
Availability of data and materials
All relevant data are included in this published article.

Declarations
Ethics approval and consent to participate
The kidney ischemia/reperfusion animal model and its study was approvedby the Institutional Animal Care and Use Committee of National Taiwan Uni‑
versity (with IACUC Approval No. 20180123) and conducted with complianceof the standards established in the Guide for the Care and Use of Laboratory
Animals.
Consent for publication
Not applicable.
Competing interests
The authors declare that they have no competing interests.
Author details
1
Department of Biochemistry and Molecular Cell Biology, School of Medicine,College of Medicine, Taipei Medical University, 250 Wuxing Street, Tai‑pei 11031, Taiwan. 2 Graduate Institute of Medical Sciences, College of Medi‑cine, Taipei Medical University, 250 Wuxing Street, Taipei 11031, Taiwan. 3 TMU
Research Center of Cell Therapy and Regeneration Medicine, Taipei Medical
University, 250 Wuxing Street, Taipei 11031, Taiwan. 4 Department of Obstetrics
and Gynecology, College of Medicine, National Taiwan University, Taipei 10041,
Taiwan. 5 Department of Obstetrics and Gynecology, National Taiwan
University Hospital Yunlin Branch, Yunlin 64041, Taiwan. 6 Institute of Atomic
and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan. 7 Department
and Graduate Institute of Pharmacology, College of Medicine, National Taiwan
University, Taipei 10617, Taiwan. 8 Department of Chemical Engineering,
National Taiwan University of Science and Technology, Taipei 106, Taiwan.
9International PhD Program for Cell Therapy and Regeneration Medicine,College of Medicine, Taipei Medical University, Taipei 11031, Taiwan. 10 Center
for Reproductive Medicine, Taipei Medical University Hospital, Taipei Medical
University, Taipei 11031, Taiwan. 11 Comprehensive Cancer Center of Taipei
Medical University, Taipei 11031, Taiwan. 12 The PhD Program for Transla‑
tional Medicine, College of Medical Science and Technology, Taipei Medical
University, Taipei 11031, Taiwan. 13 Research Center for Developmental Biology
and Regenerative Medicine, National Taiwan University, Taipei 100, Taiwan.
Received: 14 November 2020 Accepted: 7 April 2021

References
1. Aijaz A, Li M, Smith D, Khong D, LeBlon C, Fenton OS, et al. Biomanu‑
facturing for clinically advanced cell therapies. Nat Biomed Eng.
2018;2(6):362–76.
2. Friedenstein AJ, Piatetzky S II, Petrakova KV. Osteogenesis in transplantsof bone marrow cells. J Embryol Exp Morphol. 1966;16(3):381–90.
3. Diehl R, Ferrara F, Müller C, Dreyer AY, McLeod DD, Fricke S, et al.
Immunosuppression for in vivo research: state-of-the-art protocols andexperimental approaches. Cell Mol Immunol. 2017;14(2):146–79.
4. Martin I, Galipeau J, Kessler C, Le Blanc K, Dazzi F. Challenges for mesen‑chymal stromal cell therapies. Sci Transl Med. 2019. https://​doi.​org/​10.​1126/​scitr​anslm​ed.​aat21​89.
5. Friedenstein AJ, Petrakova KV, Kurolesova AI, Frolova GP. Heterotopic
of bone marrow. Analysis of precursor cells for osteogenic and hemat‑
opoietic tissues. Transplantation. 1968;6(2):230–47.

Page 31 of 38

6. Erices A, Conget P, Minguell JJ. Mesenchymal progenitor cells in humanumbilical cord blood. Br J Haematol. 2000;109(1):235–42.
7. Heidari B, Shirazi A, Akhondi MM, Hassanpour H, Behzadi B, Naderi
MM, et al. Comparison of proliferative and multilineage differentiation
potential of sheep mesenchymal stem cells derived from bone marrow,
liver, and adipose tissue. Avicenna J Med Biotechnol. 2013;5(2):104–17.
8. Fukuchi Y, Nakajima H, Sugiyama D, Hirose I, Kitamura T, Tsuji K. Humanplacenta-derived cells have mesenchymal stem/progenitor cell poten‑
tial. Stem Cells. 2004;22(5):649–58.
9. Gronthos S, Mankani M, Brahim J, Robey PG, Shi S. Postnatal humandental pulp stem cells (DPSCs) in vitro and in vivo. Proc Natl Acad Sci U
S A. 2000;97(25):13625–30.
10. Schwab KE, Gargett CE. Co-expression of two perivascular cell markers
isolates mesenchymal stem-like cells from human endometrium. Hum
Reprod. 2007;22(11):2903–11.
11. in `t Anker PS, Scherjon SA, Kleijburg-van der Keur C, Noort WA, Claas
FHJ, Willemze R, et al. Amniotic fluid as a novel source of mesenchymal
stem cells for therapeutic transplantation. Blood. 2003;102(4):1548–9.
12. Young HE, Steele TA, Bray RA, Hudson J, Floyd JA, Hawkins K, et al.
Human reserve pluripotent mesenchymal stem cells are present in theconnective tissues of skeletal muscle and dermis derived from fetal,
adult, and geriatric donors. Anat Rec. 2001;264(1):51–62.
13. Gong X, Sun Z, Cui D, Xu X, Zhu H, Wang L, et al. Isolation and character‑ization of lung resident mesenchymal stem cells capable of differentiat‑
ing into alveolar epithelial type II cells. Cell Biol Int. 2014;38(4):405–11.
14. Lazarus HM, Haynesworth SE, Gerson SL, Rosenthal NS, Caplan AI.
Ex vivo expansion and subsequent infusion of human bone marrowderived stromal progenitor cells (mesenchymal progenitor cells): impli‑
cations for therapeutic use. Bone Marrow Transplant. 1995;16(4):557–64.
15. Horwitz EM, Prockop DJ, Fitzpatrick LA, Koo WW, Gordon PL, Neel M,
et al. Transplantability and therapeutic effects of bone marrow-derived
mesenchymal cells in children with osteogenesis imperfecta. Nat Med.
1999;5(3):309–13.
16. Gotts JE, Matthay MA. Mesenchymal stem cells and acute lung injury.
Crit Care Clin. 2011;27(3):719–33.
17. Yuan SF, Jiang T, Sun LH, Zheng RJ, Cao GQ, Ahat NZ, et al. Use of bonemesenchymal stem cells to treat rats with acute liver failure. Genet Mol
Res. 2014;13(3):6962–80.
18. Qian H, Yang H, Xu W, Yan Y, Chen Q, Zhu W, et al. Bone marrow mesen‑chymal stem cells ameliorate rat acute renal failure by differentiation
into renal tubular epithelial-like cells. Int J Mol Med. 2008;22(3):325–32.
19. Ringden O, Uzunel M, Rasmusson I, Remberger M, Sundberg B, Lonnies
H, et al. Mesenchymal stem cells for treatment of therapy-resistantgraft-versus-host disease. Transplantation. 2006;81(10):1390–7.
20. Le Blanc K, Rasmusson I, Sundberg B, Gotherstrom C, Hassan M,
Uzunel M, et al. Treatment of severe acute graft-versus-host disease
with third party haploidentical mesenchymal stem cells. Lancet.
2004;363(9419):1439–41.
21. Le Blanc K, Frassoni F, Ball L, Locatelli F, Roelofs H, Lewis I, et al. Mesen‑chymal stem cells for treatment of steroid-resistant, severe, acute graftversus-host disease: a phase II study. Lancet. 2008;371(9624):1579–86.
22. Schuleri KH, Feigenbaum GS, Centola M, Weiss ES, Zimmet JM, Turney J,
et al. Autologous mesenchymal stem cells produce reverse remodellingin chronic ischaemic cardiomyopathy. Eur Heart J. 2009;30(22):2722–32.
23. Cai M, Shen R, Song L, Lu M, Wang J, Zhao S, et al. Bone Marrow
Mesenchymal Stem Cells (BM-MSCs) Improve Heart Function in
Swine Myocardial Infarction Model through Paracrine Effects. Sci Rep.
2016;6:28250.
24. Tomita S, Li RK, Weisel RD, Mickle DA, Kim EJ, Sakai T, et al. Autologoustransplantation of bone marrow cells improves damaged heart func‑
tion. Circulation. 1999;100(19 Suppl):Ii247–56.
25. Pei Z, Zeng J, Song Y, Gao Y, Wu R, Chen Y, et al. In vivo imaging to moni‑
tor differentiation and therapeutic effects of transplanted mesenchy‑
mal stem cells in myocardial infarction. Sci Rep. 2017;7(1):6296.
26. Gholamrezanezhad A, Mirpour S, Bagheri M, Mohamadnejad M,
Alimoghaddam K, Abdolahzadeh L, et al. In vivo tracking of 111In-oxine
labeled mesenchymal stem cells following infusion in patients withadvanced cirrhosis. Nucl Med Biol. 2011;38(7):961–7.
27. Urban VS, Kiss J, Kovacs J, Gocza E, Vas V, Monostori E, et al. Mesen‑chymal stem cells cooperate with bone marrow cells in therapy of
diabetes. Stem Cells. 2008;26(1):244–53.

Zhuang et al. J Biomed Sci(2021) 28:28

28. Li Y, Liu J, Liao G, Zhang J, Chen Y, Li L, et al. Early intervention withmesenchymal stem cells prevents nephropathy in diabetic rats byameliorating the inflammatory microenvironment. Int J Mol Med.
2018;41(5):2629–39.
29. Sykova E, Jendelova P. In vivo tracking of stem cells in brain and spinal
cord injury. Prog Brain Res. 2007;161:367–83.
30. Cofano F, Boido M, Monticelli M, Zenga F, Ducati A, Vercelli A, et al. Mes‑
enchymal stem cells for spinal cord injury: current options, limitations,and future of cell therapy. Int J Mol Sci. 2019;20(11):2698.
31. Cyranoski D. Japan’s approval of stem-cell treatment for spinal-cord
injury concerns scientists. Nature. 2019;565(7741):544–5.
32. Delling U, Brehm W, Metzger M, Ludewig E, Winter K, Julke H. In vivo
tracking and fate of intra-articularly injected superparamagnetic ironoxide particle-labeled multipotent stromal cells in an ovine model ofosteoarthritis. Cell Transplant. 2015;24(11):2379–90.
33. Pak J, Lee JH, Pak N, Pak Y, Park KS, Jeon JH, et al. Cartilage regenerationin humans with adipose tissue-derived stem cells and adipose stromal
vascular fraction cells: updated status. Int J Mol Sci. 2018;19(7):2146.
34. Nam Y, Rim YA, Lee J, Ju JH. Current therapeutic strategies for stem cellbased cartilage regeneration. Stem Cells Int. 2018;2018:8490489.
35. Wang CZ, Eswaramoorthy R, Lin TH, Chen CH, Fu YC, Wang CK, et al.
Enhancement of chondrogenesis of adipose-derived stem cells in
HA-PNIPAAm-CL hydrogel for cartilage regeneration in rabbits. Sci Rep.
2018;8(1):10526.
36. Satue M, Schuler C, Ginner N, Erben RG. Intra-articularly injected
mesenchymal stem cells promote cartilage regeneration, but do not
permanently engraft in distant organs. Sci Rep. 2019;9(1):10153.
37. Qi Y, Yang Z, Ding Q, Zhao T, Huang Z, Feng G. Targeted transplanta‑tion of iron oxide-labeled, adipose-derived mesenchymal stem cells inpromoting meniscus regeneration following a rabbit massive meniscal
defect. Exp Ther Med. 2016;11(2):458–66.
38. Bedford J, Enria D, Giesecke J, Heymann DL, Ihekweazu C, Kobin‑
ger G, et al. COVID-19: towards controlling of a pandemic. Lancet.
2020;395(10229):1015–8.
39. Thompson M, Mei SHJ, Wolfe D, Champagne J, Fergusson D, Stewart
DJ, et al. Cell therapy with intravascular administration of mesenchymal
stromal cells continues to appear safe: An updated systematic review
and meta-analysis. EClinMed. 2020. https://​doi.​org/​10.​1016/j.​eclinm.​
2019.​100249.
40. Caplan AI, Bruder SP. Mesenchymal stem cells: building blocks
for molecular medicine in the 21st century. Trends Mol Med.
2001;7(6):259–64.
41. Mandel K, Yang Y, Schambach A, Glage S, Otte A, Hass R. Mesenchymal
stem cells directly interact with breast cancer cells and promote tumor
cell growth in vitro and in vivo. Stem Cells Dev. 2013;22(23):3114–27.
42. Kouris NA, Schaefer JA, Hatta M, Freeman BT, Kamp TJ, Kawaoka Y,
et al. Directed fusion of mesenchymal stem cells with cardiomyo‑cytes via VSV-G facilitates stem cell programming. Stem Cells Int.
2012;2012:414038.
43. Iso Y, Spees JL, Serrano C, Bakondi B, Pochampally R, Song YH, et al.
Multipotent human stromal cells improve cardiac function after
myocardial infarction in mice without long-term engraftment. Biochem
Biophys Res Commun. 2007;354(3):700–6.
44. Lee RH, Pulin AA, Seo MJ, Kota DJ, Ylostalo J, Larson BL, et al. Intra‑
venous hMSCs improve myocardial infarction in mice because cells
embolized in lung are activated to secrete the anti-inflammatory
protein TSG-6. Cell Stem Cell. 2009;5(1):54–63.
45. Babenko VA, Silachev DN, Popkov VA, Zorova LD, Pevzner IB, Plotnikov
EY, et al. Miro1 enhances mitochondria transfer from multipotent mes‑enchymal stem Cells (MMSC) to neural cells and improves the efficacy
of cell recovery. Molecules. 2018;23(3):687.
46. Li X, Liu L, Yang J, Yu Y, Chai J, Wang L, et al. Exosome derived fromhuman umbilical cord mesenchymal stem cell mediates MiR-181c
attenuating burn-induced excessive inflammation. EBioMedicine.
2016;8:72–82.
47. Gnecchi M, Danieli P, Malpasso G, Ciuffreda MC. Paracrine mecha‑
nisms of mesenchymal stem cells in tissue repair. Methods Mol Biol.
2016;1416:123–46.
48. Luz-Crawford P, Djouad F, Toupet K, Bony C, Franquesa M, Hoogduijn
MJ, et al. Mesenchymal stem cell-derived interleukin 1 receptor

Page 32 of 38

49.

50.
51.
52.

53.

54.

55.
56.

57.

58.

59.

60.

61.

62.

63.
64.
65.
66.
67.

antagonist promotes macrophage polarization and inhibits B cell dif‑ferentiation. Stem Cells. 2016;34(2):483–92.
Melief SM, Geutskens SB, Fibbe WE, Roelofs H. Multipotent stromal cells
skew monocytes towards an anti-inflammatory interleukin-10-pro‑ducing phenotype by production of interleukin-6. Haematologica.
2013;98(6):888–95.
Tang JM, Wang JN, Zhang L, Zheng F, Yang JY, Kong X, et al. VEGF/SDF-1
promotes cardiac stem cell mobilization and myocardial repair in theinfarcted heart. Cardiovasc Res. 2011;91(3):402–11.
Wang CY, Yang HB, Hsu HS, Chen LL, Tsai CC, Tsai KS, et al. Mesenchymal
stem cell-conditioned medium facilitates angiogenesis and fracture
healing in diabetic rats. J Tissue Eng Regen Med. 2012;6(7):559–69.
Hu CH, Tseng YW, Chiou CY, Lan KC, Chou CH, Tai CS, et al. Bone marrowconcentrate-induced mesenchymal stem cell conditioned medium
facilitates wound healing and prevents hypertrophic scar formation in a
rabbit ear model. Stem Cell Res Ther. 2019;10(1):275.
Liu B, Ding FX, Liu Y, Xiong G, Lin T, He DW, et al. Human umbilical
cord-derived mesenchymal stem cells conditioned medium attenuate
interstitial fibrosis and stimulate the repair of tubular epithelial cells
in an irreversible model of unilateral ureteral obstruction. Nephrology(Carlton). 2018;23(8):728–36.
Faezi M, Nasseri Maleki S, Aboutaleb N, Nikougoftar M. The membranemesenchymal stem cell derived conditioned medium exerts neuropro‑
tection against focal cerebral ischemia by targeting apoptosis. J Chem
Neuroanat. 2018;94:21–31.
Kwon HM, Hur SM, Park KY, Kim CK, Kim YM, Kim HS, et al. Multiple
paracrine factors secreted by mesenchymal stem cells contribute toangiogenesis. Vascul Pharmacol. 2014;63(1):19–28.
Terunuma A, Ashiba K, Takane T, Sakaguchi Y, Terunuma H. Com‑
parative transcriptomic analysis of human mesenchymal stem cells
derived from dental pulp and adipose tissues. J Stem Cells Regen Med.
2019;15(1):8–11.
Du WJ, Chi Y, Yang ZX, Li ZJ, Cui JJ, Song BQ, et al. Heterogeneity ofproangiogenic features in mesenchymal stem cells derived from bonemarrow, adipose tissue, umbilical cord, and placenta. Stem Cell Res
Ther. 2016;7(1):163.
Overath JM, Gauer S, Obermüller N, Schubert R, Schäfer R, Geiger H,
et al. Short-term preconditioning enhances the therapeutic potential of
adipose-derived stromal/stem cell-conditioned medium in cisplatininduced acute kidney injury. Exp Cell Res. 2016;342(2):175–83.
Bai M, Zhang L, Fu B, Bai J, Zhang Y, Cai G, et al. IL-17A improves theefficacy of mesenchymal stem cells in ischemic-reperfusion renal injury
by increasing Treg percentages by the COX-2/PGE2 pathway. KidneyInt. 2018;93(4):814–25.
von Bahr L, Sundberg B, Lönnies L, Sander B, Karbach H, HägglundH, et al. Long-term complications, immunologic effects, and role ofpassage for outcome in mesenchymal stromal cell therapy. Biol Blood
Marrow Transplant. 2012;18(4):557–64.
Zhuang Y, Li D, Fu J, Shi Q, Lu Y, Ju X. Comparison of biological proper‑
ties of umbilical cord-derived mesenchymal stem cells from early andlate passages: immunomodulatory ability is enhanced in aged cells.
Mol Med Rep. 2015;11(1):166–74.
Choi MR, Kim HY, Park JY, Lee TY, Baik CS, Chai YG, et al. Selection of opti‑
mal passage of bone marrow-derived mesenchymal stem cells for stem
cell therapy in patients with amyotrophic lateral sclerosis. Neurosci Lett.
2010;472(2):94–8.
Xu Y, Shi T, Xu A, Zhang L. 3D spheroid culture enhances survival andtherapeutic capacities of MSCs injected into ischemic kidney. J Cell Mol
Med. 2016;20(7):1203–13.
Sumanasinghe RD, Pfeiler TW, Monteiro-Riviere NA, Loboa EG. Expres‑sion of proinflammatory cytokines by human mesenchymal stem cells
in response to cyclic tensile strain. J Cell Physiol. 2009;219(1):77–83.
Karussis D, Kassis I. The potential use of stem cells in multiple sclerosis:
An overview of the preclinical experience. Clin Neurol Neurosurg.
2008;110(9):889–96.
Zhang J, Lv S, Liu X, Song B, Shi L. Umbilical cord mesenchymal stem
cell treatment for Crohn’s disease: a randomized controlled clinical trial.
Gut Liver. 2018;12(1):73–8.
Kim Y, Jin HJ, Heo J, Ju H, Lee HY, Kim S, et al. Small hypoxia-primed
mesenchymal stem cells attenuate graft-versus-host disease. Leukemia.
2018;32(12):2672–84.

Zhuang et al. J Biomed Sci(2021) 28:28

68. Donzelli E, Scuteri A. Mesenchymal stem cells: a trump card for thetreatment of diabetes? Biomedicines. 2020;8(5):112.
69. Sala E, Genua M, Petti L, Anselmo A, Arena V, Cibella J, et al.
Mesenchymal stem cells reduce colitis in mice via release of TSG6,
independently of their localization to the intestine. Gastroenterology.
2015;149(1):163-76.e20.
70. Simovic Markovic B, Gazdic M, Arsenijevic A, Jovicic N, Jeremic
J, Djonov V, et al. Mesenchymal stem cells attenuate cisplatininduced nephrotoxicity in iNOS-dependent manner. Stem Cells Int.
2017;2017:1315378.
71. Putra A, Ridwan FB, Putridewi AI, Kustiyah AR, Wirastuti K, Sadyah
NAC, et al. The role of TNF-alpha induced MSCs on suppressive
inflammation by increasing TGF-beta and IL-10. Open Access Maced
J Med Sci. 2018;6(10):1779–83.
72. Gieseke F, Kruchen A, Tzaribachev N, Bentzien F, Dominici M, Muller
I. Proinflammatory stimuli induce galectin-9 in human mesenchy‑
mal stromal cells to suppress T-cell proliferation. Eur J Immunol.
2013;43(10):2741–9.
73. Nemeth K, Leelahavanichkul A, Yuen PS, Mayer B, Parmelee A, Doi K,
et al. Bone marrow stromal cells attenuate sepsis via prostaglandin
E(2)-dependent reprogramming of host macrophages to increase
their interleukin-10 production. Nat Med. 2009;15(1):42–9.
74. Choi H, Lee RH, Bazhanov N, Oh JY, Prockop DJ. Anti-inflammatory
protein TSG-6 secreted by activated MSCs attenuates zymosaninduced mouse peritonitis by decreasing TLR2/NF-kappaB signaling
in resident macrophages. Blood. 2011;118(2):330–8.
75. Chiossone L, Conte R, Spaggiari GM, Serra M, Romei C, Bellora F, et al.
Mesenchymal stromal cells induce peculiar alternatively activatedmacrophages capable of dampening both innate and adaptive
immune responses. Stem Cells. 2016;34(7):1909–21.
76. Gazdic M, Markovic BS, Arsenijevic A, Jovicic N, Acovic A, Harrell CR,
et al. Crosstalk between mesenchymal stem cells and T regulatory
cells is crucially important for the attenuation of acute liver injury.
Liver Transpl. 2018;24(5):687–702.
77. Wu L, Leijten J, van Blitterswijk CA, Karperien M. Fibroblast growth
factor-1 is a mesenchymal stromal cell-secreted factor stimulating
proliferation of osteoarthritic chondrocytes in co-culture. Stem Cells
Dev. 2013;22(17):2356–67.
78. Imberti B, Morigi M, Tomasoni S, Rota C, Corna D, Longaretti L, et al.
Insulin-like growth factor-1 sustains stem cell mediated renal repair. J
Am Soc Nephrol. 2007;18(11):2921–8.
79. Tang YL, Zhao Q, Qin X, Shen L, Cheng L, Ge J, et al. Paracrine
action enhances the effects of autologous mesenchymal stem celltransplantation on vascular regeneration in rat model of myocardial
infarction. Ann Thorac Surg. 2005;80(1):229–36.
80. Dufourcq P, Descamps B, Tojais NF, Leroux L, Oses P, Daret D, et al.
Secreted frizzled-related protein-1 enhances mesenchymal stem cellfunction in angiogenesis and contributes to neovessel maturation.
Stem Cells. 2008;26(11):2991–3001.
81. Mirotsou M, Zhang Z, Deb A, Zhang L, Gnecchi M, Noiseux N, et al.
Secreted frizzled related protein 2 (Sfrp2) is the key Akt-mesenchy‑
mal stem cell-released paracrine factor mediating myocardial survivaland repair. Proc Natl Acad Sci U S A. 2007;104(5):1643–8.
82. Togel F, Weiss K, Yang Y, Hu Z, Zhang P, Westenfelder C. Vasculotropic,
paracrine actions of infused mesenchymal stem cells are importantto the recovery from acute kidney injury. Am J Physiol Renal Physiol.
2007;292(5):F1626–35.
83. Ong HT, Dilley RJ. Novel non-angiogenic role for mesenchymal stem
cell-derived vascular endothelial growth factor on keratinocytes dur‑
ing wound healing. Cytokine Growth Factor Rev. 2018;44:69–79.
84. Li X, An G, Wang Y, Liang D, Zhu Z, Tian L. Targeted migration of bonemarrow mesenchymal stem cells inhibits silica-induced pulmonary
fibrosis in rats. Stem Cell Res Ther. 2018;9(1):335.
85. Milosavljevic N, Gazdic M, Simovic Markovic B, Arsenijevic A, Nurkovic
J, Dolicanin Z, et al. Mesenchymal stem cells attenuate liver fibrosis
by suppressing Th17 cells - an experimental study. Transpl Int.
2018;31(1):102–15.
86. Meier RP, Mahou R, Morel P, Meyer J, Montanari E, Muller YD, et al.
Microencapsulated human mesenchymal stem cells decrease liver
fibrosis in mice. J Hepatol. 2015;62(3):634–41.

Page 33 of 38

87. Shen Q, Chen B, Xiao Z, Zhao L, Xu X, Wan X, et al. Paracrine factors frommesenchymal stem cells attenuate epithelial injury and lung fibrosis.
Mol Med Rep. 2015;11(4):2831–7.
88. Li X, Wang Y, An G, Liang D, Zhu Z, Lian X, et al. Bone marrow mes‑enchymal stem cells attenuate silica-induced pulmonary fibrosis via
paracrine mechanisms. Toxicol Lett. 2017;270:96–107.
89. Ono M, Ohkouchi S, Kanehira M, Tode N, Kobayashi M, Ebina M, et al.
Mesenchymal stem cells correct inappropriate epithelial-mesenchyme
relation in pulmonary fibrosis using stanniocalcin-1. Mol Ther.
2015;23(3):549–60.
90. Xu X, Xu Z, Xu Y, Cui G. Effects of mesenchymal stem cell transplanta‑tion on extracellular matrix after myocardial infarction in rats. Coron
Artery Dis. 2005;16(4):245–55.
91. Javadov S, Kozlov AV, Camara AKS. Mitochondria in health and diseases.
Cells. 2020;9(5):1177.
92. Lin HY, Liou CW, Chen SD, Hsu TY, Chuang JH, Wang PW, et al. Mito‑
chondrial transfer from Wharton’s jelly-derived mesenchymal stem cells
to mitochondria-defective cells recaptures impaired mitochondrial
function. Mitochondrion. 2015;22:31–44.
93. Chinnery HR, Pearlman E, McMenamin PG. Cutting edge: Membrane
nanotubes in vivo: a feature of MHC class II+ cells in the mouse cornea.
J Immunol. 2008;180(9):5779–83.
94. Liu K, Ji K, Guo L, Wu W, Lu H, Shan P, et al. Mesenchymal stem cells res‑cue injured endothelial cells in an in vitro ischemia-reperfusion model
via tunneling nanotube like structure-mediated mitochondrial transfer.
Microvasc Res. 2014;92:10–8.
95. Islam MN, Das SR, Emin MT, Wei M, Sun L, Westphalen K, et al. Mitochon‑
drial transfer from bone-marrow-derived stromal cells to pulmonary
alveoli protects against acute lung injury. Nat Med. 2012;18(5):759–65.
96. Li X, Zhang Y, Yeung SC, Liang Y, Liang X, Ding Y, et al. Mitochondrialtransfer of induced pluripotent stem cell-derived mesenchymal stem
cells to airway epithelial cells attenuates cigarette smoke-induced dam‑age. Am J Respir Cell Mol Biol. 2014;51(3):455–65.
97. Ahmad T, Mukherjee S, Pattnaik B, Kumar M, Singh S, Kumar M, et al.
Miro1 regulates intercellular mitochondrial transport & enhances mes‑enchymal stem cell rescue efficacy. EMBO J. 2014;33(9):994–1010.
98. Marlein CR, Zaitseva L, Piddock RE, Robinson SD, Edwards DR, Shafat
MS, et al. NADPH oxidase-2 derived superoxide drives mitochondrialtransfer from bone marrow stromal cells to leukemic blasts. Blood.
2017;130(14):1649–60.
99. Wang J, Liu X, Qiu Y, Shi Y, Cai J, Wang B, et al. Cell adhesion-mediatedmitochondria transfer contributes to mesenchymal stem cell-induced
chemoresistance on T cell acute lymphoblastic leukemia cells. J Hema‑
tol Oncol. 2018;11(1):11.
100. Moschoi R, Imbert V, Nebout M, Chiche J, Mary D, Prebet T, et al.
Protective mitochondrial transfer from bone marrow stromal cells
to acute myeloid leukemic cells during chemotherapy. Blood.
2016;128(2):253–64.
101. Raposo G, Stahl PD. Extracellular vesicles: a new communication para‑digm? Nat Rev Mol Cell Biol. 2019;20(9):509–10.
102. Bai L, Shao H, Wang H, Zhang Z, Su C, Dong L, et al. Effects of mesen‑chymal stem cell-derived exosomes on experimental autoimmune
uveitis. Sci Rep. 2017;7(1):4323.
103. Ma M, Li B, Zhang M, Zhou L, Yang F, Ma F, et al. Therapeutic effects ofmesenchymal stem cell-derived exosomes on retinal detachment. Exp
Eye Res. 2020;191:107899.
104. Zou L, Ma X, Lin S, Wu B, Chen Y, Peng C. Bone marrow mesenchymal
stem cell-derived exosomes protect against myocardial infarction bypromoting autophagy. Exp Ther Med. 2019;18(4):2574–82.
105. Nojehdehi S, Soudi S, Hesampour A, Rasouli S, Soleimani M, Hashemi
SM. Immunomodulatory effects of mesenchymal stem cell-derived
exosomes on experimental type-1 autoimmune diabetes. J Cell Bio‑chem. 2018;119(11):9433–43.
106. Dalirfardouei R, Jamialahmadi K, Jafarian AH, Mahdipour E. Promising
effects of exosomes isolated from menstrual blood-derived mesenchy‑
mal stem cell on wound-healing process in diabetic mouse model. J
Tissue Eng Regen Med. 2019;13(4):555–68.
107. Furuta T, Miyaki S, Ishitobi H, Ogura T, Kato Y, Kamei N, et al. Mesenchy‑
mal stem cell-derived exosomes promote fracture healing in a mousemodel. Stem Cells Transl Med. 2016;5(12):1620–30.

Zhuang et al. J Biomed Sci(2021) 28:28

108. Li Y, Yang YY, Ren JL, Xu F, Chen FM, Li A. Exosomes secreted by stem
cells from human exfoliated deciduous teeth contribute to functional
recovery after traumatic brain injury by shifting microglia M1/M2 polari‑zation in rats. Stem Cell Res Ther. 2017;8(1):198.
109. Sun G, Li G, Li D, Huang W, Zhang R, Zhang H, et al. hucMSC derived
exosomes promote functional recovery in spinal cord injury mice
via attenuating inflammation. Mater Sci Eng C Mater Biol Appl.
2018;89:194–204.
110. Akyurekli C, Le Y, Richardson RB, Fergusson D, Tay J, Allan DS. A sys‑
tematic review of preclinical studies on the therapeutic potential ofmesenchymal stromal cell-derived microvesicles. Stem Cell Rev Rep.
2015;11(1):150–60.
111. Chen W, Huang Y, Han J, Yu L, Li Y, Lu Z, et al. Immunomodulatory
effects of mesenchymal stromal cells-derived exosome. Immunol Res.
2016;64(4):831–40.
112. Tamura R, Uemoto S, Tabata Y. Immunosuppressive effect of mesen‑chymal stem cell-derived exosomes on a concanavalin A-induced liver
injury model. Inflamm Regen. 2016;36:26.
113. Zhang B, Wu X, Zhang X, Sun Y, Yan Y, Shi H, et al. Human umbilical cordmesenchymal stem cell exosomes enhance angiogenesis through theWnt4/β-catenin pathway. Stem Cells Transl Med. 2015;4(5):513–22.
114. Shabbir A, Cox A, Rodriguez-Menocal L, Salgado M, Van Badiavas E.
Mesenchymal stem cell exosomes induce proliferation and migrationof normal and chronic wound fibroblasts, and enhance angiogenesis
in vitro. Stem Cells Dev. 2015;24(14):1635–47.
115. Liu D, Kou X, Chen C, Liu S, Liu Y, Yu W, et al. Circulating apoptotic
bodies maintain mesenchymal stem cell homeostasis and amelio‑
rate osteopenia via transferring multiple cellular factors. Cell Res.
2018;28(9):918–33.
116. Liu H, Liu S, Qiu X, Yang X, Bao L, Pu F, et al. Donor MSCs release apop‑
totic bodies to improve myocardial infarction via autophagy regulationin recipient cells. Autophagy. 2020. https://​doi.​org/​10.​1080/​15548​627.​
2020.​17171​28.
117. Tokhanbigli S, Baghaei K, Asadirad A, Hashemi SM, Asadzadeh-Aghdaei
H, Zali MR. Immunoregulatory impact of human mesenchymal-condi‑
tioned media and mesenchymal derived exosomes on monocytes. Mol
Biol Res Commun. 2019;8(2):79–89.
118. Wen S, Dooner M, Papa E, Del Tatto M, Pereira M, Borgovan T, et al.
Biodistribution of mesenchymal stem cell-derived extracellular
vesicles in a radiation injury bone marrow murine model. Int J Mol Sci.
2019;20(21):5468.
119. Moon GJ, Sung JH, Kim DH, Kim EH, Cho YH, Son JP, et al. Application ofmesenchymal stem cell-derived extracellular vesicles for stroke: biodis‑
tribution and MicroRNA study. Transl Stroke Res. 2019;10(5):509–21.
120. Li JH, Fan WS, Wang MM, Wang YH, Ren ZG. Effects of mesenchymal
stem cells on solid tumor metastasis in experimental cancer models: asystematic review and meta-analysis. J Transl Med. 2018;16(1):113.
121. Lin YH, Chen YH, Chang HY, Au HK, Tzeng CR, Huang YH. Chronic
niche inflammation in endometriosis-associated infertility: cur‑rent understanding and future therapeutic strategies. Int J Mol Sci.
2018;19(8):2385.
122. Chulpanova DS, Kitaeva KV, Tazetdinova LG, James V, Rizvanov AA,
Solovyeva VV. Application of mesenchymal stem cells for therapeutic
agent delivery in anti-tumor treatment. Front Pharmacol. 2018;9:259.
123. Mognetti B, La Montagna G, Perrelli MG, Pagliaro P, Penna C. Bone mar‑row mesenchymal stem cells increase motility of prostate cancer cells
via production of stromal cell-derived factor-1alpha. J Cell Mol Med.
2013;17(2):287–92.
124. Ma M, Ye JY, Deng R, Dee CM, Chan GC. Mesenchymal stromal cells may
enhance metastasis of neuroblastoma via SDF-1/CXCR4 and SDF-1/
CXCR7 signaling. Cancer Lett. 2011;312(1):1–10.
125. Ma Z, Cui X, Lu L, Chen G, Yang Y, Hu Y, et al. Exosomes from glioma cells
induce a tumor-like phenotype in mesenchymal stem cells by activat‑
ing glycolysis. Stem Cell Res Ther. 2019;10(1):60.
126. Ren W, Hou J, Yang C, Wang H, Wu S, Wu Y, et al. Extracellular vesicles
secreted by hypoxia pre-challenged mesenchymal stem cells promote
non-small cell lung cancer cell growth and mobility as well as mac‑rophage M2 polarization via miR-21-5p delivery. J Exp Clin Cancer Res.
2019;38(1):62.
127. Fontanella R, Pelagalli A, Nardelli A, D’Alterio C, Ierano C, Cerchia L,
et al. A novel antagonist of CXCR4 prevents bone marrow-derived

Page 34 of 38

128.

129.
130.

131.

132.
133.
134.

135.

136.

137.

138.

139.
140.

141.

142.
143.

144.

145.

mesenchymal stem cell-mediated osteosarcoma and hepatocellular
carcinoma cell migration and invasion. Cancer Lett. 2016;370(1):100–7.
Chen J, Ji T, Wu D, Jiang S, Zhao J, Lin H, et al. Human mesenchymal
stem cells promote tumor growth via MAPK pathway and metastasis
by epithelial mesenchymal transition and integrin α5 in hepatocellular
carcinoma. Cell Death Dis. 2019;10(6):425.
Shinagawa K, Kitadai Y, Tanaka M, Sumida T, Kodama M, Higashi Y, et al.
Mesenchymal stem cells enhance growth and metastasis of coloncancer. Int J Cancer. 2010;127(10):2323–33.
Shinagawa K, Kitadai Y, Tanaka M, Sumida T, Onoyama M, Ohnishi
M, et al. Stroma-directed imatinib therapy impairs the tumorpromoting effect of bone marrow-derived mesenchymal stem cells
in an orthotopic transplantation model of colon cancer. Int J Cancer.
2013;132(4):813–23.
Liu CJ, Wang YK, Kuo FC, Hsu WH, Yu FJ, Hsieh S, et al. Helicobacter
pylori infection-induced hepatoma-derived growth factor regulates thedifferentiation of human mesenchymal stem cells to myofibroblast-likecells. Cancers (Basel). 2018;10(12):479.
Tsai KS, Yang SH, Lei YP, Tsai CC, Chen HW, Hsu CY, et al. Mesenchymal
stem cells promote formation of colorectal tumors in mice. Gastroen‑
terology. 2011;141(3):1046–56.
Huang WH, Chang MC, Tsai KS, Hung MC, Chen HL, Hung SC. Mesen‑chymal stem cells promote growth and angiogenesis of tumors inmice. Oncogene. 2013;32(37):4343–54.
Hogan NM, Joyce MR, Murphy JM, Barry FP, O’Brien T, Kerin MJ, et al.
Impact of mesenchymal stem cell secreted PAI-1 on colon cancer
cell migration and proliferation. Biochem Biophys Res Commun.
2013;435(4):574–9.
De Boeck A, Pauwels P, Hensen K, Rummens JL, Westbroek W, Hendrix
A, et al. Bone marrow-derived mesenchymal stem cells promotecolorectal cancer progression through paracrine neuregulin 1/HER3
signalling. Gut. 2013;62(4):550–60.
Fu X, Xie F, Gong F, Yang Z, Lv X, Li X, et al. Suppression of PTBP1
signaling is responsible for mesenchymal stem cell induced invasionof low malignancy cancer cells. Biochim Biophys Acta Mol Cell Res.
2018;1865:1552–65.
Chen K, Liu Q, Tsang LL, Ye Q, Chan HC, Sun Y, et al. Human MSCs
promotes colorectal cancer epithelial-mesenchymal transition andprogression via CCL5/beta-catenin/Slug pathway. Cell Death Dis.
2017;8(5):e2819.
Qi J, Zhou Y, Jiao Z, Wang X, Zhao Y, Li Y, et al. Exosomes derived
from human bone marrow mesenchymal stem cells promote tumor
growth through hedgehog signaling pathway. Cell Physiol Biochem.
2017;42(6):2242–54.
Tu B, Du L, Fan QM, Tang Z, Tang TT. STAT3 activation by IL-6 frommesenchymal stem cells promotes the proliferation and metastasis ofosteosarcoma. Cancer Lett. 2012;325(1):80–8.
Kawano M, Tanaka K, Itonaga I, Iwasaki T, Tsumura H. Interaction
between human osteosarcoma and mesenchymal stem cells via aninterleukin-8 signaling loop in the tumor microenvironment. Cell Com‑mun Signal. 2018;16(1):13.
Pietrovito L, Leo A, Gori V, Lulli M, Parri M, Becherucci V, et al. Bonemarrow-derived mesenchymal stem cells promote invasiveness andtransendothelial migration of osteosarcoma cells via a mesenchymal toamoeboid transition. Mol Oncol. 2018;12(5):659–76.
Karnoub AE, Dash AB, Vo AP, Sullivan A, Brooks MW, Bell GW, et al.
Mesenchymal stem cells within tumour stroma promote breast cancer
metastasis. Nature. 2007;449(7162):557–63.
Chaturvedi P, Gilkes DM, Takano N, Semenza GL. Hypoxia-inducible
factor-dependent signaling between triple-negative breast cancer cells
and mesenchymal stem cells promotes macrophage recruitment. Proc
Natl Acad Sci U S A. 2014;111(20):E2120–9.
Liubomirski Y, Lerrer S, Meshel T, Rubinstein-Achiasaf L, Morein D,
Wiemann S, et al. Tumor-stroma-inflammation networks promote
pro-metastatic chemokines and aggressiveness characteristics in triplenegative breast cancer. Front Immunol. 2019;10:757.
Ono M, Kosaka N, Tominaga N, Yoshioka Y, Takeshita F, Takahashi RU,
et al. Exosomes from bone marrow mesenchymal stem cells contain amicroRNA that promotes dormancy in metastatic breast cancer cells.
Sci Signal. 2014;7(332):ra63.

Zhuang et al. J Biomed Sci(2021) 28:28

146. Wessely A, Waltera A, Reichert TE, Stockl S, Grassel S, Bauer RJ.
Induction of ALP and MMP9 activity facilitates invasive behavior inheterogeneous human BMSC and HNSCC 3D spheroids. FASEB J.
2019. https://​doi.​org/​10.​1096/​fj.​20190​0925R.
147. Hong D, Liu T, Huang W, Liao Y, Wang L, Zhang Z, et al. Gremlin1
delivered by mesenchymal stromal cells promoted epithelial-mesen‑chymal transition in human esophageal squamous cell carcinoma.
Cell Physiol Biochem. 2018;47(5):1785–99.
148. Akimoto K, Kimura K, Nagano M, Takano S, To’a Salazar G, Yamashita
T, et al. Umbilical cord blood-derived mesenchymal stem cells
inhibit, but adipose tissue-derived mesenchymal stem cells
promote, glioblastoma multiforme proliferation. Stem Cells Dev.
2013;22(9):1370–86.
149. Park YM, Yoo SH, Kim SH. Adipose-derived stem cells induced
EMT-like changes in H358 lung cancer cells. Anticancer Res.
2013;33(10):4421–30.
150. Wang Y, Liu J, Jiang Q, Deng J, Xu F, Chen X, et al. Human adiposederived mesenchymal stem cell-secreted CXCL1 and CXCL8 facilitate
breast tumor growth by promoting angiogenesis. Stem Cells.
2017;35(9):2060–70.
151. Maj M, Bajek A, Nalejska E, Porowinska D, Kloskowski T, Gackowska
L, et al. Influence of mesenchymal stem cells conditioned media on
proliferation of urinary tract cancer cell Lines and their sensitivity to
ciprofloxacin. J Cell Biochem. 2017;118(6):1361–8.
152. Chu Y, Tang H, Guo Y, Guo J, Huang B, Fang F, et al. Adipose-derived
mesenchymal stem cells promote cell proliferation and invasion ofepithelial ovarian cancer. Exp Cell Res. 2015;337(1):16–27.
153. Coffelt SB, Marini FC, Watson K, Zwezdaryk KJ, Dembinski JL, LaMarca
HL, et al. The pro-inflammatory peptide LL-37 promotes ovarian
tumor progression through recruitment of multipotent mesenchy‑
mal stromal cells. Proc Natl Acad Sci U S A. 2009;106(10):3806–11.
154. Yu JM, Jun ES, Bae YC, Jung JS. Mesenchymal stem cells derived fromhuman adipose tissues favor tumor cell growth in vivo. Stem Cells
Dev. 2008;17(3):463–73.
155. Lin R, Wang S, Zhao RC. Exosomes from human adipose-derived
mesenchymal stem cells promote migration through Wnt signal‑
ing pathway in a breast cancer cell model. Mol Cell Biochem.
2013;383(1–2):13–20.
156. Chen DR, Lu DY, Lin HY, Yeh WL. Mesenchymal stem cell-induced
doxorubicin resistance in triple negative breast cancer. Biomed Res
Int. 2014;2014:532161.
157. Li T, Zhang C, Ding Y, Zhai W, Liu K, Bu F, et al. Umbilical cord-derived
mesenchymal stem cells promote proliferation and migration in
MCF-7 and MDA-MB-231 breast cancer cells through activation of
the ERK pathway. Oncol Rep. 2015;34(3):1469–77.
158. Dong L, Pu Y, Zhang L, Qi Q, Xu L, Li W, et al. Human umbilical cordmesenchymal stem cell-derived extracellular vesicles promote lungadenocarcinoma growth by transferring miR-410. Cell Death Dis.
2018;9(2):218.
159. Zhao X, Wu X, Qian M, Song Y, Wu D, Zhang W. Knockdown of
TGF-beta1 expression in human umbilical cord mesenchymal stem
cells reverts their exosome-mediated EMT promoting effect on lungcancer cells. Cancer Lett. 2018;428:34–44.
160. Pavon LF, Sibov TT, de Souza AV, da Cruz EF, Malheiros SMF, Cabral
FR, et al. Tropism of mesenchymal stem cell toward CD133(+) stem
cell of glioblastoma in vitro and promote tumor proliferation in vivo.
Stem Cell Res Ther. 2018;9(1):310.
161. Vulcano F, Milazzo L, Ciccarelli C, Eramo A, Sette G, Mauro A, et al.
Wharton’s jelly mesenchymal stromal cells have contrasting effects
on proliferation and phenotype of cancer stem cells from different
subtypes of lung cancer. Exp Cell Res. 2016;345(2):190–8.
162. de Vieira Castro J, Gomes ED, Granja S, Anjo SI, Baltazar F, Manadas B,
et al. Impact of mesenchymal stem cells’ secretome on glioblastoma
pathophysiology. J Transl Med. 2017;15(1):200.
163. Du T, Ju G, Wu S, Cheng Z, Cheng J, Zou X, et al. Microvesicles derived
from human Wharton’s jelly mesenchymal stem cells promote
human renal cancer cell growth and aggressiveness through induc‑tion of hepatocyte growth factor. PLoS ONE. 2014;9(5):e96836.
164. Hao Y, Baker D, Ten Dijke P. TGF-β-mediated epithelial-mesenchymaltransition and cancer metastasis. Int J Mol Sci. 2019;20(11):2767.

Page 35 of 38

165. Li GC, Ye QH, Xue YH, Sun HJ, Zhou HJ, Ren N, et al. Human mesenchy‑
mal stem cells inhibit metastasis of a hepatocellular carcinoma modelusing the MHCC97-H cell line. Cancer Sci. 2010;101(12):2546–53.
166. Ma P, Pan Y, Li W, Sun C, Liu J, Xu T, et al. Extracellular vesicles-mediatednoncoding RNAs transfer in cancer. J Hematol Oncol. 2017;10(1):57.
167. Gauthaman K, Yee FC, Cheyyatraivendran S, Biswas A, Choolani
M, Bongso A. Human umbilical cord Wharton’s jelly stem cell(hWJSC) extracts inhibit cancer cell growth in vitro. J Cell Biochem.
2012;113(6):2027–39.
168. Dzobo K, Vogelsang M, Thomford NE, Dandara C, Kallmeyer K, Pepper
MS, et al. Wharton’s jelly-derived mesenchymal stromal cells andfibroblast-derived extracellular matrix synergistically activate apoptosis
in a p21-dependent mechanism in WHCO1 and MDA MB 231 cancer
cells in vitro. Stem Cells Int. 2016;2016:4842134.
169. Ganta C, Chiyo D, Ayuzawa R, Rachakatla R, Pyle M, Andrews G, et al. Rat
umbilical cord stem cells completely abolish rat mammary carcinomas
with no evidence of metastasis or recurrence 100 days post-tumor cell
inoculation. Cancer Res. 2009;69(5):1815–20.
170. Yang C, Lei D, Ouyang W, Ren J, Li H, Hu J, et al. Conditioned media fromhuman adipose tissue-derived mesenchymal stem cells and umbilical
cord-derived mesenchymal stem cells efficiently induced the apoptosis
and differentiation in human glioma cell lines in vitro. Biomed Res Int.
2014;2014:109389.
171. Kolosa K, Motaln H, Herold-Mende C, Korsic M, Lah TT. Paracrine effectsof mesenchymal stem cells induce senescence and differentiation ofglioblastoma stem-like cells. Cell Transplant. 2015;24(4):631–44.
172. Velpula KK, Dasari VR, Tsung AJ, Gondi CS, Klopfenstein JD, Mohanam S,
et al. Regulation of glioblastoma progression by cord blood stem cells is
mediated by downregulation of cyclin D1. PLoS ONE. 2011;6(3):e18017.
173. Dasari VR, Velpula KK, Kaur K, Fassett D, Klopfenstein JD, Dinh DH,
et al. Cord blood stem cell-mediated induction of apoptosis in glioma
downregulates X-linked inhibitor of apoptosis protein (XIAP). PLoS ONE.
2010;5(7):e11813.
174. Jiao H, Guan F, Yang B, Li J, Shan H, Song L, et al. Human umbilical cord
blood-derived mesenchymal stem cells inhibit C6 glioma via down‑
regulation of cyclin D1. Neurol India. 2011;59(2):241–7.
175. Yuan Y, Zhou C, Chen X, Tao C, Cheng H, Lu X. Suppression of tumor
cell proliferation and migration by human umbilical cord mesenchymal
stem cells: a possible role for apoptosis and Wnt signaling. Oncol Lett.
2018;15(6):8536–44.
176. Qiao L, Xu Z, Zhao T, Zhao Z, Shi M, Zhao RC, et al. Suppression of tumo‑
rigenesis by human mesenchymal stem cells in a hepatoma model. Cell
Res. 2008;18(4):500–7.
177. Khalil C, Moussa M, Azar A, Tawk J, Habbouche J, Salameh R, et al. Antiproliferative effects of mesenchymal stem cells (MSCs) derived frommultiple sources on ovarian cancer cell lines: an in-vitro experimental
study. J Ovarian Res. 2019;12(1):70.
178. Kalamegam G, Sait KHW, Ahmed F, Kadam R, Pushparaj PN, Anfinan N,
et al. Human Wharton’s jelly stem cell (hWJSC) extracts inhibit ovariancancer cell lines OVCAR3 and SKOV3 in vitro by inducing cell cycle
arrest and apoptosis. Front Oncol. 2018;8:592.
179. Gauthaman K, Fong CY, Arularasu S, Subramanian A, Biswas A, Choolani
M, et al. Human Wharton’s jelly stem cell conditioned medium andcell-free lysate inhibit human osteosarcoma and mammary carci‑
noma cell growth in vitro and in xenograft mice. J Cell Biochem.
2013;114(2):366–77.
180. Wu S, Ju GQ, Du T, Zhu YJ, Liu GH. Microvesicles derived from humanumbilical cord Wharton’s jelly mesenchymal stem cells attenuate blad‑
der tumor cell growth in vitro and in vivo. PLoS ONE. 2013;8(4):e61366.
181. Lin DH, Biswas A, Choolani M, Fong CY, Bongso A. Induction of immu‑
nogenic cell death in lymphoma cells by Wharton’s jelly mesenchymal
stem cell conditioned medium. Stem Cell Rev Rep. 2017;13(6):801–16.
182. Lin HD, Fong CY, Biswas A, Choolani M, Bongso A. Human umbilicalcord Wharton’s jelly stem cell conditioned medium induces tumoricidal
effects on lymphoma cells through hydrogen peroxide mediation. J
Cell Biochem. 2016;117(9):2045–55.
183. Fonseka M, Ramasamy R, Tan BC, Seow HF. Human umbilical cord
blood-derived mesenchymal stem cells (hUCB-MSC) inhibit the prolif‑
eration of K562 (human erythromyeloblastoid leukaemic cell line). Cell
Biol Int. 2012;36(9):793–801.

Zhuang et al. J Biomed Sci(2021) 28:28

184. Ho IA, Toh HC, Ng WH, Teo YL, Guo CM, Hui KM, et al. Human bone mar‑row-derived mesenchymal stem cells suppress human glioma growththrough inhibition of angiogenesis. Stem Cells. 2013;31(1):146–55.
185. Dasari VR, Kaur K, Velpula KK, Dinh DH, Tsung AJ, Mohanam S, et al.
Downregulation of Focal Adhesion Kinase (FAK) by cord blood
stem cells inhibits angiogenesis in glioblastoma. Aging (Albany NY).
2010;2(11):791–803.
186. Bu S, Wang Q, Zhang Q, Sun J, He B, Xiang C, et al. Human endometrial
mesenchymal stem cells exhibit intrinsic anti-tumor properties onhuman epithelial ovarian cancer cells. Sci Rep. 2016;6:37019.
187. Dasari VR, Kaur K, Velpula KK, Gujrati M, Fassett D, Klopfenstein JD, et al.
Upregulation of PTEN in glioma cells by cord blood mesenchymal stem
cells inhibits migration via downregulation of the PI3K/Akt pathway.
PLoS ONE. 2010;5(4):e10350.
188. Velpula KK, Dasari VR, Tsung AJ, Dinh DH, Rao JS. Transcriptional repres‑sion of Mad-Max complex by human umbilical cord blood stem cells
downregulates extracellular signal-regulated kinase in glioblastoma.
Stem Cells Dev. 2012;21(10):1779–93.
189. Visweswaran M, Arfuso F, Dilley RJ, Newsholme P, Dharmarajan A. The
inhibitory influence of adipose tissue-derived mesenchymal stem cell
environment and Wnt antagonism on breast tumour cell lines. Int J
Biochem Cell Biol. 2018;95:63–72.
190. Liu J, Han G, Liu H, Qin C. Suppression of cholangiocarcinoma cell
growth by human umbilical cord mesenchymal stem cells: a possible
role of Wnt and Akt signaling. PLoS ONE. 2013;8(4):e62844.
191. Wang ML, Pan CM, Chiou SH, Chen WH, Chang HY, Lee OK, et al.
Oncostatin m modulates the mesenchymal-epithelial transition of lungadenocarcinoma cells by a mesenchymal stem cell-mediated paracrine
effect. Cancer Res. 2012;72(22):6051–64.
192. Qiao L, Zhao TJ, Wang FZ, Shan CL, Ye LH, Zhang XD. NF-kappaB down‑
regulation may be involved the depression of tumor cell proliferation
mediated by human mesenchymal stem cells. Acta Pharmacol Sin.
2008;29(3):333–40.
193. Klein D, Schmetter A, Imsak R, Wirsdorfer F, Unger K, Jastrow H, et al.
Therapy with multipotent mesenchymal stromal cells protects lungs
from radiation-induced injury and reduces the risk of lung metastasis.
Antioxid Redox Signal. 2016;24(2):53–69.
194. Chen F, Zhou K, Zhang L, Ma F, Chen D, Cui J, et al. Mesenchymal
stem cells induce granulocytic differentiation of acute promyelo‑
cytic leukemic cells via IL-6 and MEK/ERK pathways. Stem Cells Dev.
2013;22(13):1955–67.
195. Sage EK, Thakrar RM, Janes SM. Genetically modified mesenchymal
stromal cells in cancer therapy. Cytotherapy. 2016;18(11):1435–45.
196. Park SA, Ryu CH, Kim SM, Lim JY, Park SI, Jeong CH, et al. CXCR4transfected human umbilical cord blood-derived mesenchymal stem
cells exhibit enhanced migratory capacity toward gliomas. Int J Oncol.
2011;38(1):97–103.
197. Kim SM, Oh JH, Park SA, Ryu CH, Lim JY, Kim DS, et al. Irradiation
enhances the tumor tropism and therapeutic potential of tumor necro‑
sis factor-related apoptosis-inducing ligand-secreting human umbilicalcord blood-derived mesenchymal stem cells in glioma therapy. StemCells. 2010;28(12):2217–28.
198. Sasportas LS, Kasmieh R, Wakimoto H, Hingtgen S, Water JA van de,
Mohapatra G, et al. Assessment of therapeutic efficacy and fate ofengineered human mesenchymal stem cells for cancer therapy. Proc
Natl Acad Sci USA. 2009;106(12):4822–7.
199. Ryu CH, Park SH, Park SA, Kim SM, Lim JY, Jeong CH, et al. Gene therapy
of intracranial glioma using interleukin 12-secreting human umbili‑
cal cord blood-derived mesenchymal stem cells. Hum Gene Ther.
2011;22(6):733–43.
200. Fan S, Gao H, Ji W, Zhu F, Sun L, Liu Y, et al. Umbilical cord-derived
mesenchymal stromal/stem cells expressing IL-24 induce apoptosis ingliomas. J Cell Physiol. 2019. https://​doi.​org/​10.​1002/​jcp.​29095.
201. Nakamizo A, Marini F, Amano T, Khan A, Studeny M, Gumin J, et al.
Human bone marrow-derived mesenchymal stem cells in the treat‑ment of gliomas. Cancer Res. 2005;65(8):3307–18.
202. Matsuzuka T, Rachakatla RS, Doi C, Maurya DK, Ohta N, KawabataA, et al. Human umbilical cord matrix-derived stem cells expressing
interferon-beta gene significantly attenuate bronchioloalveolar carci‑
noma xenografts in SCID mice. Lung Cancer. 2010;70(1):28–36.

Page 36 of 38

203. Xie C, Xie DY, Lin BL, Zhang GL, Wang PP, Peng L, et al. Interferon-betagene-modified human bone marrow mesenchymal stem cells attenu‑
ate hepatocellular carcinoma through inhibiting AKT/FOXO3a pathway.
Br J Cancer. 2013;109(5):1198–205.
204. Li Q, Wijesekera O, Salas SJ, Wang JY, Zhu M, Aprhys C, et al. Mesen‑chymal stem cells from human fat engineered to secrete BMP4 arenononcogenic, suppress brain cancer, and prolong survival. Clin Cancer
Res. 2014;20(9):2375–87.
205. Zhang X, Yang Y, Zhang L, Lu Y, Zhang Q, Fan D, et al. Mesenchymal
stromal cells as vehicles of tetravalent bispecific Tandab (CD3/CD19) for
the treatment of B cell lymphoma combined with IDO pathway inhibi‑
tor D-1-methyl-tryptophan. J Hematol Oncol. 2017;10(1):56.
206. Yuan Y, Lu X, Tao CL, Chen X, Shao HW, Huang SL. Forced expression ofindoleamine-2,3-dioxygenase in human umbilical cord-derived mesen‑chymal stem cells abolishes their anti-apoptotic effect on leukemia celllines in vitro. Vitro Cell Dev Biol Anim. 2013;49(10):752–8.
207. Yan C, Li S, Li Z, Peng H, Yuan X, Jiang L, et al. Human umbilical cordmesenchymal stem cells as vehicles of CD20-specific TRAIL fusion
protein delivery: a double-target therapy against non-Hodgkin’s lym‑
phoma. Mol Pharm. 2013;10(1):142–51.
208. Yan C, Yang M, Li Z, Li S, Hu X, Fan D, et al. Suppression of orthotopicallyimplanted hepatocarcinoma in mice by umbilical cord-derived mesen‑chymal stem cells with sTRAIL gene expression driven by AFP promoter.
Biomaterials. 2014;35(9):3035–43.
209. Zhu X, Su D, Xuan S, Ma G, Dai Z, Liu T, et al. Gene therapy of gastriccancer using LIGHT-secreting human umbilical cord blood-derived
mesenchymal stem cells. Gastric Cancer. 2013;16(2):155–66.
210. Hu W, Wang J, He X, Zhang H, Yu F, Jiang L, et al. Human umbilical bloodmononuclear cell-derived mesenchymal stem cells serve as interleu‑
kin-21 gene delivery vehicles for epithelial ovarian cancer therapy innude mice. Biotechnol Appl Biochem. 2011;58(6):397–404.
211. Jing W, Chen Y, Lu L, Hu X, Shao C, Zhang Y, et al. Human umbilicalcord blood-derived mesenchymal stem cells producing IL15 eradicate
established pancreatic tumor in syngeneic mice. Mol Cancer Ther.
2014;13(8):2127–37.
212. Kucerova L, Altanerova V, Matuskova M, Tyciakova S, Altaner C. Adipose
tissue–derived human mesenchymal stem cells mediated prodrug
cancer gene therapy. Cancer Res. 2007;67(13):6304–13.
213. Krueger TEG, Thorek DLJ, Denmeade SR, Isaacs JT, Brennen WN. Concise
review: mesenchymal stem cell-based drug delivery: The good, thebad, the ugly, and the promise. Stem Cells Transl Med. 2018;7(9):651–63.
214. Oja S, Komulainen P, Penttila A, Nystedt J, Korhonen M. Automatedimage analysis detects aging in clinical-grade mesenchymal stromal
cell cultures. Stem Cell Res Ther. 2018;9(1):6.
215. Gao J, Dennis JE, Muzic RF, Lundberg M, Caplan AI. The dynamic in vivo
distribution of bone marrow-derived mesenchymal stem cells after
infusion. Cells Tissues Organs. 2001;169(1):12–20.
216. Niyibizi C, Wang S, Mi Z, Robbins PD. The fate of mesenchymal stem
cells transplanted into immunocompetent neonatal mice: implications
for skeletal gene therapy via stem cells. Mol Ther. 2004;9(6):955–63.
217. Fischer UM, Harting MT, Jimenez F, Monzon-Posadas WO, Xue H,
Savitz SI, et al. Pulmonary passage is a major obstacle for intravenous
stem cell delivery: the pulmonary first-pass effect. Stem Cells Dev.
2009;18(5):683–92.
218. Schrepfer S, Deuse T, Reichenspurner H, Fischbein MP, Robbins RC,
Pelletier MP. Stem cell transplantation: the lung barrier. Transplant Proc.
2007;39(2):573–6.
219. Kean TJ, Lin P, Caplan AI, Dennis JE. MSCs: Delivery routes and engraft‑
ment, cell-targeting strategies, and immune modulation. Stem Cells Int.
2013;2013:732742.
220. Ge J, Guo L, Wang S, Zhang Y, Cai T, Zhao RC, et al. The size of mesen‑chymal stem cells is a significant cause of vascular obstructions andstroke. Stem Cell Rev Rep. 2014;10(2):295–303.
221. Argibay B, Trekker J, Himmelreich U, Beiras A, Topete A, Taboada P,
et al. Intraarterial route increases the risk of cerebral lesions after
mesenchymal cell administration in animal model of ischemia. Sci Rep.
2017;7:40758.
222. Cui LL, Nitzsche F, Pryazhnikov E, Tibeykina M, Tolppanen L, Rytkönen
J, et al. Integrin α4 overexpression on rat mesenchymal stem cells
enhances transmigration and reduces cerebral embolism after intraca‑rotid injection. Stroke. 2017;48(10):2895–900.

Zhuang et al. J Biomed Sci(2021) 28:28

223. Cui LL, Kerkelä E, Bakreen A, Nitzsche F, Andrzejewska A, Nowakowski
A, et al. The cerebral embolism evoked by intra-arterial delivery ofallogeneic bone marrow mesenchymal stem cells in rats is related tocell dose and infusion velocity. Stem Cell Res Ther. 2015;6(1):11.
224. Fabian C, Naaldijk Y, Leovsky C, Johnson AA, Rudolph L, Jaeger C, et al.
Distribution pattern following systemic mesenchymal stem cell injec‑tion depends on the age of the recipient and neuronal health. Stem
Cell Res Ther. 2017;8(1):85.
225. Zhou S, Greenberger JS, Epperly MW, Goff JP, Adler C, Leboff MS, et al.
Age-related intrinsic changes in human bone-marrow-derived mesen‑chymal stem cells and their differentiation to osteoblasts. Aging Cell.
2008;7(3):335–43.
226. Choudhery MS, Badowski M, Muise A, Pierce J, Harris DT. Donor age
negatively impacts adipose tissue-derived mesenchymal stem cell
expansion and differentiation. J Transl Med. 2014;12:8.
227. Rosova I, Dao M, Capoccia B, Link D, Nolta JA. Hypoxic precondition‑
ing results in increased motility and improved therapeutic potential of
human mesenchymal stem cells. Stem Cells. 2008;26(8):2173–82.
228. Berglund AK, Fortier LA, Antczak DF, Schnabel LV. Immunoprivileged no
more: measuring the immunogenicity of allogeneic adult mesenchy‑
mal stem cells. Stem Cell Res Ther. 2017;8(1):288.
229. Zangi L, Margalit R, Reich-Zeliger S, Bachar-Lustig E, Beilhack A, Negrin
R, et al. Direct imaging of immune rejection and memory induction by
allogeneic mesenchymal stromal cells. Stem Cells. 2009;27(11):2865–74.
230. Joswig AJ, Mitchell A, Cummings KJ, Levine GJ, Gregory CA, Smith R
3rd, et al. Repeated intra-articular injection of allogeneic mesenchymal
stem cells causes an adverse response compared to autologous cells in
the equine model. Stem Cell Res Ther. 2017;8(1):42.
231. Moll G, Ankrum JA, Kamhieh-Milz J, Bieback K, Ringden O, Volk HD,
et al. Intravascular mesenchymal stromal/stem cell therapy productdiversification: time for new clinical guidelines. Trends Mol Med.
2019;25(2):149–63.
232. Toma C, Wagner WR, Bowry S, Schwartz A, Villanueva F. Fate of cultureexpanded mesenchymal stem cells in the microvasculature: in vivo
observations of cell kinetics. Circ Res. 2009;104(3):398–402.
233. Oeller M, Laner-Plamberger S, Hochmann S, Ketterl N, Feichtner M,
Brachtl G, et al. Selection of tissue factor-deficient cell transplants as anovel strategy for improving hemocompatibility of human bone mar‑row stromal cells. Theranostics. 2018;8(5):1421–34.
234. Wu Z, Zhang S, Zhou L, Cai J, Tan J, Gao X, et al. Thromboembolism
induced by umbilical cord mesenchymal stem cell infusion: a report oftwo cases and literature review. Transplant Proc. 2017;49(7):1656–8.
235. Koc ON, Gerson SL, Cooper BW, Dyhouse SM, Haynesworth SE, Caplan
AI, et al. Rapid hematopoietic recovery after coinfusion of autologousblood stem cells and culture-expanded marrow mesenchymal stem
cells in advanced breast cancer patients receiving high-dose chemo‑
therapy. J Clin Oncol. 2000;18(2):307–16.
236. Meyerrose TE, De Ugarte DA, Hofling AA, Herrbrich PE, Cordonnier TD,
Shultz LD, et al. In vivo distribution of human adipose-derived mes‑enchymal stem cells in novel xenotransplantation models. Stem Cells.
2007;25(1):220–7.
237. Toupet K, Maumus M, Peyrafitte JA, Bourin P, van Lent PL, Ferreira R,
et al. Long-term detection of human adipose-derived mesenchymal
stem cells after intraarticular injection in SCID mice. Arthritis Rheum.
2013;65(7):1786–94.
238. Wang H, Liang X, Xu ZP, Crawford DHG, Liu X, Roberts MS. A physiologi‑
cally based kinetic model for elucidating the in vivo distribution ofadministered mesenchymal stem cells. Sci Rep. 2016;6:22293.
239. Kircher MF, Gambhir SS, Grimm J. Noninvasive cell-tracking methods.
Nat Rev Clin Oncol. 2011;8(11):677–88.
240. Grange C, Tapparo M, Bruno S, Chatterjee D, Quesenberry PJ, Tetta C,
et al. Biodistribution of mesenchymal stem cell-derived extracellular
vesicles in a model of acute kidney injury monitored by optical imag‑
ing. Int J Mol Med. 2014;33(5):1055–63.
241. Li M, Luo X, Lv X, Liu V, Zhao G, Zhang X, et al. In vivo human adiposederived mesenchymal stem cell tracking after intra-articular delivery ina rat osteoarthritis model. Stem Cell Res Ther. 2016;7(1):160.
242. Kumar M, Yasotha T, Singh RK, Singh R, Kumar K, Ranjan R, et al. Genera‑tion of transgenic mesenchymal stem cells expressing green fluores‑
cent protein as reporter gene using no viral vector in caprine. Indian J
Exp Biol. 2013;51(7):502–9.

Page 37 of 38

243. Ansari AM, Ahmed AK, Matsangos AE, Lay F, Born LJ, Marti G, et al. Cel‑lular GFP toxicity and immunogenicity: potential confounders in in vivo
cell tracking experiments. Stem Cell Rev Rep. 2016;12(5):553–9.
244. Ning X, Bao H, Liu X, Fu H, Wang W, Huang J, et al. Long-term in vivo
CT tracking of mesenchymal stem cells labeled with Au@BSA@PLL
nanotracers. Nanoscale. 2019;11(43):20932–41.
245. Huang J, Huang J, Ning X, Luo W, Chen M, Wang Z, et al. CT/NIRF dualmodal imaging tracking and therapeutic efficacy of transplanted mes‑enchymal stem cells labeled with Au nanoparticles in silica-induced
pulmonary fibrosis. J Mater Chem B. 2020;8(8):1713–27.
246. Bose RJC, Mattrey RF. Accomplishments and challenges in stem cell
imaging in vivo. Drug Discov Today. 2019;24(2):492–504.
247. Ohki A, Saito S, Fukuchi K. Magnetic resonance imaging of umbilicalcord stem cells labeled with superparamagnetic iron oxide nanopar‑
ticles: effects of labelling and transplantation parameters. Sci Rep.
2020;10(1):13684.
248. Muhammad G, Xu J, Bulte JWM, Jablonska A, Walczak P, Janowski M.
Transplanted adipose-derived stem cells can be short-lived yet acceler‑
ate healing of acid-burn skin wounds: a multimodal imaging study. Sci
Rep. 2017;7(1):4644.
249. Nguyen PK, Riegler J, Wu JC. Stem cell imaging: from bench to bedside.
Cell Stem Cell. 2014;14(4):431–44.
250. Templin C, Zweigerdt R, Schwanke K, Olmer R, Ghadri JR, Emmert MY,
et al. Transplantation and tracking of human-induced pluripotent
stem cells in a pig model of myocardial infarction: assessment of cell
survival, engraftment, and distribution by hybrid single photon emis‑
sion computed tomography/computed tomography of sodium iodide
symporter transgene expression. Circulation. 2012;126(4):430–9.
251. Chin BB, Nakamoto Y, Bulte JW, Pittenger MF, Wahl R, Kraitchman DL.
111In oxine labelled mesenchymal stem cell SPECT after intrave‑nous administration in myocardial infarction. Nucl Med Commun.
2003;24(11):1149–54.
252. Patrick PS, Kolluri KK, Zaw Thin M, Edwards A, Sage EK, Sanderson T,
et al. Lung delivery of MSCs expressing anti-cancer protein TRAIL visual‑ised with (89)Zr-oxine PET-CT. Stem Cell Res Ther. 2020;11(1):256.
253. Bulte JWM, Daldrup-Link HE. Clinical tracking of cell transfer and celltransplantation: trials and tribulations. Radiology. 2018;289(3):604–15.
254. Dhada KS, Hernandez DS, Suggs LJ. In vivo photoacoustic tracking of
mesenchymal stem cell viability. ACS Nano. 2019;13(7):7791–9.
255. Liu H, Liu S, Liang Y, Deng Z, Wang Y, Yan F. Real-time imaging trackingof mesenchymal stem cells labeled with lipid-poly(lactic-co-glycolicacid) nanobubbles. J Biomed Nanotechnol. 2019;15(11):2271–80.
256. Lee HY, Li Z, Chen K, Hsu AR, Xu C, Xie J, et al. PET/MRI dual-modality
tumor imaging using arginine-glycine-aspartic (RGD)-conjugatedradiolabeled iron oxide nanoparticles. J Nucl Med. 2008;49(8):1371–9.
257. Tang Y, Zhang C, Wang J, Lin X, Zhang L, Yang Y, et al. MRI/SPECT/fluo‑
rescent tri-modal probe for evaluating the homing and therapeutic
efficacy of transplanted mesenchymal stem cells in a rat ischemic
stroke model. Adv Funct Mater. 2015;25(7):1024–34.
258. Zaw Thin M, Allan H, Bofinger R, Kostelec TD, Guillaume S, Connell
JJ, et al. Multi-modal imaging probe for assessing the efficiencyof stem cell delivery to orthotopic breast tumours. Nanoscale.
2020;12(31):16570–85.
259. Su LJ, Lin HH, Wu MS, Pan L, Yadav K, Hsu HH, et al. Intracellular deliveryof luciferase with fluorescent nanodiamonds for dual-modality imagingof human stem cells. Bioconjug Chem. 2019;30(8):2228–37.
260. Vaijayanthimala V, Tzeng YK, Chang HC, Li CL. The biocompatibility offluorescent nanodiamonds and their mechanism of cellular uptake.
Nanotechnology. 2009;20(42):425103.
261. Wu T-J, Tzeng Y-K, Chang W-W, Cheng C-A, Kuo Y, Chien C-H, et al.
Tracking the engraftment and regenerative capabilities of transplantedlung stem cells using fluorescent nanodiamonds. Nat Nanotechnol.
2013;8:682.
262. Su L-J, Wu M-S, Hui YY, Chang B-M, Pan L, Hsu P-C, et al. Fluorescent
nanodiamonds enable quantitative tracking of human mesenchymal
stem cells in miniature pigs. Sci Rep. 2017;7:45607.
263. Wu YC, Wang YC, Wang WT, Wang HD, Lin HH, Su LJ, et al. Fluorescent
nanodiamonds enable long-term detection of human adipose-derived
stem/stromal cells in an in vivo chondrogenesis model using decellu‑
larized extracellular matrices and fibrin glue polymer. Polymers (Basel).
2019;11:9.

Zhuang et al. J Biomed Sci(2021) 28:28

264. Harting MT, Jimenez F, Cox CS Jr. The pulmonary first-pass effect,
xenotransplantation and translation to clinical trials–a commentary.
Brain. 2008;131(Pt 8):e100.
265. Crop MJ, Baan CC, Korevaar SS, Ijzermans JN, Weimar W, Hoogduijn
MJ. Human adipose tissue-derived mesenchymal stem cells induce
explosive T-cell proliferation. Stem Cells Dev. 2010;19(12):1843–53.
266. Chapel A, Bertho JM, Bensidhoum M, Fouillard L, Young RG, Frick J, et al.
Mesenchymal stem cells home to injured tissues when co-infused withhematopoietic cells to treat a radiation-induced multi-organ failure
syndrome. J Gene Med. 2003;5(12):1028–38.
267. Blanco JF, Villarón EM, Pescador D, da Casa C, Gómez V, Redondo AM,
et al. Autologous mesenchymal stromal cells embedded in tricalcium
phosphate for posterolateral spinal fusion: results of a prospective
phase I/II clinical trial with long-term follow-up. Stem Cell Res Ther.
2019;10(1):63.
268. Kabat M, Bobkov I, Kumar S, Grumet M. Trends in mesenchymal stem
cell clinical trials 2004–2018: Is efficacy optimal in a narrow dose range?
Stem Cells Transl Med. 2020;9(1):17–27.
269. Introna M, Golay J. Tolerance to bone marrow transplantation: do mes‑enchymal stromal cells still have a future for acute or chronic GvHD?
Front Immunol. 2020;11:609063.
270. Boltze J, Modo MM, Mays RW, Taguchi A, Jolkkonen J, Savitz SI, et al.
Stem cells as an emerging paradigm in stroke 4: advancing and acceler‑ating preclinical research. Stroke. 2019;50(11):3299–306.
271. Galipeau J, Krampera M, Barrett J, Dazzi F, Deans RJ, DeBruijn J, et al.
International Society for Cellular Therapy perspective on immune func‑
tional assays for mesenchymal stromal cells as potency release criterion
for advanced phase clinical trials. Cytotherapy. 2016;18(2):151–9.
272. Caplan H, Olson SD, Kumar A, George M, Prabhakara KS, Wenzel P, et al.
Mesenchymal stromal cell therapeutic delivery: translational challenges
to clinical application. Front Immunol. 2019;10:1645.
273. Jackson ML, Ruppert KA, Kota DJ, Prabhakara KS, Hetz RA, Aertker BM,
et al. Clinical parameters affecting multipotent adult progenitor cells
in vitro. Heliyon. 2019;5(10):e02532.
274. Giri J, Galipeau J. Mesenchymal stromal cell therapeutic potency isdependent upon viability, route of delivery, and immune match. Blood
Adv. 2020;4(9):1987–97.
275. Tan Y, Salkhordeh M, Wang JP, McRae A, Souza-Moreira L, McIntyre
L, et al. Thawed mesenchymal stem cell product shows comparable
immunomodulatory potency to cultured cells in vitro and in polymicro‑bial septic animals. Sci Rep. 2019;9(1):18078.
276. Chinnadurai R, Rajan D, Qayed M, Arafat D, Garcia M, Liu Y, et al. Potency
analysis of mesenchymal stromal cells using a combinatorial assay
matrix approach. Cell Rep. 2018;22(9):2504–17.
277. Lehman N, Cutrone R, Raber A, Perry R, Van’t Hof W, Deans R, et al.
Development of a surrogate angiogenic potency assay for clinicalgrade stem cell production. Cytotherapy. 2012;14(8):994–1004.
278. Hematti P. Characterization of mesenchymal stromal cells: potency
assay development. Transfusion. 2016;56(4):32S-S35.
279. Galipeau J, Krampera M. The challenge of defining mesenchymal
stromal cell potency assays and their potential use as release criteria.
Cytotherapy. 2015;17(2):125–7.
280. Bloom DD, Centanni JM, Bhatia N, Emler CA, Drier D, Leverson GE, et al.
A reproducible immunopotency assay to measure mesenchymal stro‑
mal cell-mediated T-cell suppression. Cytotherapy. 2015;17(2):140–51.
281. Del Fattore A, Luciano R, Saracino R, Battafarano G, Rizzo C, Pascucci L,
et al. Differential effects of extracellular vesicles secreted by mesenchy‑
mal stem cells from different sources on glioblastoma cells. Expert Opin
Biol Ther. 2015;15(4):495–504.
282. Iser IC, Ceschini SM, Onzi GR, Bertoni AP, Lenz G, Wink MR. Conditioned
medium from adipose-derived stem cells (ADSCs) promotes epithelialto-mesenchymal-like transition (EMT-Like) in glioma cells in vitro. Mol
Neurobiol. 2016;53(10):7184–99.
283. Klopp AH, Zhang Y, Solley T, Amaya-Manzanares F, Marini F, Andreeff
M, et al. Omental adipose tissue-derived stromal cells promote
vascularization and growth of endometrial tumors. Clin Cancer Res.
2012;18(3):771–82.
284. Lacerda L, Debeb BG, Smith D, Larson R, Solley T, Xu W, et al. Mesenchy‑
mal stem cells mediate the clinical phenotype of inflammatory breast
cancer in a preclinical model. Breast Cancer Res. 2015;17:42.

Page 38 of 38

285. Goldstein RH, Reagan MR, Anderson K, Kaplan DL, Rosenblatt
M. Human bone marrow-derived MSCs can home to orthotopic
breast cancer tumors and promote bone metastasis. Cancer Res.
2010;70(24):10044–50.
286. Kamat P, Schweizer R, Kaenel P, Salemi S, Calcagni M, Giovanoli P, et al.
Human adipose-derived mesenchymal stromal cells may promotebreast cancer progression and metastatic spread. Plast Reconstr Surg.
2015;136(1):76–84.
287. Correa D, Somoza RA, Lin P, Schiemann WP, Caplan AI. Mesenchymal
stem cells regulate melanoma cancer cells extravasation to bone andliver at their perivascular niche. Int J Cancer. 2016;138(2):417–27.
288. Avril P, Le Nail LR, Brennan MA, Rosset P, De Pinieux G, Layrolle P, et al.
Mesenchymal stem cells increase proliferation but do not change
quiescent state of osteosarcoma cells: potential implications according
to the tumor resection status. J Bone Oncol. 2016;5(1):5–14.
289. Kucerova L, Matuskova M, Hlubinova K, Altanerova V, Altaner C. Tumor
cell behaviour modulation by mesenchymal stromal cells. Mol Cancer.
2010;9:129.
290. Bajetto A, Pattarozzi A, Corsaro A, Barbieri F, Daga A, Bosio A, et al.
Different effects of human umbilical cord mesenchymal stem cells on
glioblastoma stem cells by direct cell interaction or via released soluble
factors. Front Cell Neurosci. 2017;11:312.
291. Hendijani F, Javanmard ShH, Rafiee L, Sadeghi-Aliabadi H. Effect ofhuman Wharton’s jelly mesenchymal stem cell secretome on prolifera‑tion, apoptosis and drug resistance of lung cancer cells. Res Pharm Sci.
2015;10(2):134–42.
292. Kalamegam G, Sait KHW, Anfinan N, Kadam R, Ahmed F, Rasool M,
et al. Cytokines secreted by human Wharton’s jelly stem cells inhibit
the proliferation of ovarian cancer (OVCAR3) cells in vitro. Oncol Lett.
2019;17(5):4521–31.
293. Kalamegam G, Pushparaj PN, Khan F, Sait KH, Anfinan N, Al-Qahtani M.
Primary ovarian cancer cell inhibition by human Wharton’s Jelly stem
cells (hWJSCs): mapping probable mechanisms and targets using
systems oncology. Bioinformation. 2015;11(12):529–34.
294. Sun B, Roh KH, Park JR, Lee SR, Park SB, Jung JW, et al. Therapeuticpotential of mesenchymal stromal cells in a mouse breast cancer
metastasis model. Cytotherapy. 2009;11(3):289–98.
295. Mirabdollahi M, Haghjooyjavanmard S, Sadeghi-Aliabadi H. An antican‑
cer effect of umbilical cord-derived mesenchymal stem cell secretomeon the breast cancer cell line. Cell Tissue Bank. 2019;20(3):423–34.
296. Sun B, Yu KR, Bhandari DR, Jung JW, Kang SK, Kang KS. Human umbili‑
cal cord blood mesenchymal stem cell-derived extracellular matrix
prohibits metastatic cancer cell MDA-MB-231 proliferation. Cancer Lett.
2010;296(2):178–85.
297. Ciavarella S, Caselli A, Tamma AV, Savonarola A, Loverro G, PaganelliR, et al. A peculiar molecular profile of umbilical cord-mesenchymal
stromal cells drives their inhibitory effects on multiple myeloma cell
growth and tumor progression. Stem Cells Dev. 2015;24(12):1457–70.
298. Hendijani F, Javanmard SH, Sadeghi-aliabadi H. Human Wharton’s jelly
mesenchymal stem cell secretome display antiproliferative effect onleukemia cell line and produce additive cytotoxic effect in combination
with doxorubicin. Tissue Cell. 2015;47(3):229–34.
299. Zhang H, Wang L, Wen S, Xiang Q, Xiang X, Xu C, et al. Magnetic
resonance imaging tracking and assessing repair function of the bonemarrow mesenchymal stem cells transplantation in a rat model ofspinal cord injury. Oncotarget. 2017;8(35):58985–99.
300. Brooks A, Futrega K, Liang X, Hu X, Liu X, Crawford DHG, et al. Concise
review: quantitative detection and modeling the in vivo kinetics oftherapeutic mesenchymal stem/stromal cells. Stem Cells Transl Med.
2018;7(1):78–86.

Publisher’s NoteSpringer Nature remains neutral with regard to jurisdictional claims in pub‑lished maps and institutional affiliations.