Exosome-transmitted miR-128-3p increase chemosensitivity of oxaliplatin-resistant colorectal cancer
Authors: Peilong Li
Xiaoming Liu
Yinghui Zhao
Zhaowei Sun
Hui Tian
Lutao Du
Xin Zhang
Yujiao Xie
Weili Duan
Tong Liu
Chuanxin Wang
Yunshan Wang
Lili Wang
Journal: Molecular Cancer (2019)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: Chemoresistance; Colorectal cancer; Drug efflux; Epithelial-mesenchymal transition; Exosome
Affiliations: Department of Clinical Laboratory, The Second Hospital of Shandong University, No. 247 Beiyuan Street, Jinan, 250033, China., Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, 250012, Shandong Province, China., Department of Preventive Medicine, Shandong Provincial Traditional Chinese Medical Hospital, Jinan, 250012, People's Republic of China., Cancer Center, Qilu Hospital, Shandong University, Jinan, 250012, Shandong Province, China., Department of Surgery, The Affiliated Hospital of Medical College Qingdao University, Qingdao, 266071, Shandong Province, China., Department of Clinical Laboratory, The Second Hospital of Shandong University, No. 247 Beiyuan Street, Jinan, 250033, China. .

Abstract:  Background: Oxaliplatin resistance is a major challenge for treatment of advanced colorectal cancer (CRC). Both acquisition of epithelial-mesenchymal transition (EMT) and suppressed drug accumulation in cancer cells contributes to development of oxaliplatin resistance. Aberrant expression of small noncoding RNA, miR-128-3p, has been shown to be a key regulator in tumorigenesis and cancer development. However, its roles in the progression of CRC and oxaliplatin-resistance are largely unknown. Methods: Oxaliplatin-resistant CRC and normal intestinal FHC cells were transfected with a miR-128-3p expression lentivirus. After transfection, FHC-derived exosomes were isolated and co-cultured with CRC cells. miR-128-3p expression in resistant CRC cells, FHC cells, and exosomes was quantified by quantitative real-time PCR (RT-qPCR). The mRNA and protein levels of miR-128-3p target genes in resistant CRC cells were quantified by RT-qPCR and western blot, respectively. The effects of miR-128-3p on CRC cell viability, apoptosis, EMT, motility and drug efflux were evaluated by CCK8, flow cytometry, Transwell and wound healing assays, immunofluorescence, and atomic absorption spectrophotometry. Xenograft models were used to determine whether miR-128-3p loaded exosomes can re-sensitize CRC cells to oxaliplatin in vivo. Results: In our established stable oxaliplatin-resistant CRC cell lines, in vitro and vivo studies revealed miR-128-3p suppressed EMT and increased intracellular oxaliplatin accumulation. Importantly, our results indicated that lower miR-128-3p expression was associated with poor oxaliplatin response in advanced human CRC patients. Moreover, data showed that miR-128-3p-transfected FHC cells effectively packaged miR-128-3p into secreted exosomes and mediated miR-128-3p delivery to oxaliplatin-resistant cells, improving oxaliplatin response in CRC cells both in vitro and in vivo. In addition, miR-128-3p overexpression up-regulated E-cadherin levels and inhibited oxaliplatin-induced EMT by suppressing Bmi1 expression in resistant cells. Meanwhile, it also decreased oxaliplatin efflux through suppressed expression of the drug transporter MRP5. Conclusion: Our results demonstrate that miR-128-3p delivery via exosomes represents a novel strategy enhancing chemosensitivity in CRC through negative regulation of Bmi1 and MRP5. Moreover, miR-128-3p may be a promising diagnostic and prognostic marker for oxaliplatin-based chemotherapy. 

Retracted: No

PubPeer comments:
 there is a region of overlap in Figure 1E between the 2nd invasion and migration panels, e.g.  , 
 Figure 2F also has regions of overlap between invasion and migration panels, e.g.  , 
 Figure 5d contains regions of overlap, this time both overlapping regions are in invasion panels  , 
 2 panels in Figure 6g are duplicated in entirety  , 
 and more duplications overlab in Fig 6g  , 
 and now we have overlap between 2 panels in Figures 1 and 6 that are labeled as different things  , 
 and yet another problem with portions of panels in Figures 1 and 6 being duplicated and labeled as different things  , 
 Correction:  Following the publication of the original article [1], the authors noticed some incorrect information are shown. Inverted-microscope pictures of transwell assay were placed in the mistaken figure inadvertently and the fluorescence-microscope picture was mistakenly switched. The correct version of figure is given in Fig. 1. The authors apologize for any inconvenience caused, and these corrections do not affect the findings or conclusions of this research. The authors made a dizzying number of corrections, fixing all these duplications:      It seems like a lot to allow for correction and not a retraction. , 
 I left out the supplemental image they corrected:  **I found some additional problems that weren t addressed by the correction:**     It seems like a very large percentage of images in this paper have overlaps with others... , 
 I would also point out that the  exosomes studied here have not been purified, characterized, or studied functionally in a way that is exosome specific, reproducible, or informative. The methods section states that  Exosomes were isolated from FHC cell conditioned medium by 0.22u2009u03bcm filtration and ultracentrifugation as we previously described [24]. However, the reference is a 2006 paper that is not from  we (any of the authors), and exact instruments, rotors, settings are not provided. As a result, it is unclear exactly what methods were used. Also, the characterization by TEM and NTA is not specific to exosomes (extracellular vesicles from the multivesicular body) or to EVs in general. CD63 and CD9 are not exclusively exosomal markers. Lipid dye labeling is not specific to exosomes, and most lipid dyes will also label other particles that are often more abundant than EVs when low-purity isolations are done. The animal experiments were controlled only with PBS. Finally, there is no clear description of the cell culture media or how cells were grown or monitored, there are just three citations. These cited papers state that cells were grown in 10% FBS, and there is no mention here of moving cells into serum-free media. Additives like serum contain vast quantities of EVs that will interfere with any EV-related interpretations. , 
 Retracted [30 July 2022] .  The Editor in Chief has retracted this article because of significant concerns regarding figures 2F, 2G, 5D, 6G and additional file 10 presented in this work, which question the integrity of the data. Concerns have also been raised regarding methods used in this article, specifically the isolation of the exosomes, the animal experiment controls and the cell culture. The Editor in Chief, therefore, no longer has confidence in the presented results and the conclusions drawn in this study. None of the authors have responded to any correspondence from the editor publisher about this retraction. ,