bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from RAF-Mutant Melanomas Differentially Depend on ERK2 Over ERK1 to Support Aberrant MAPK Pathway Activation and Cell Proliferation
Authors: Crowe Matthew S. , Zavorotinskaya Tatiana , Voliva Charles F. , Shirley Matthew D. , Wang Yanqun , Ruddy David A. , Rakiec Daniel P. , Engelman Jeffery A. , Stuart Darrin D. , Freeman Alyson K.
Published: April 2023

Abstract
Half of advanced human melanomas are driven by mutant BRAF and dependent on MAPK signaling. Interestingly, the results of three independent genetic screens highlight a dependency of BRAF-mutant melanoma cell lines on BRAF and ERK2, but not ERK1. ERK2 is expressed higher in melanoma compared with other cancer types and higher than ERK1 within melanoma. However, ERK1 and ERK2 are similarly required in primary human melanocytes transformed with mutant BRAF and are expressed at a similar, lower amount compared with established cancer cell lines. ERK1 can compensate for ERK2 loss as seen by expression of ERK1 rescuing the proliferation arrest mediated by ERK2 loss (both by shRNA or inhibition by an ERK inhibitor). ERK2 knockdown, as opposed to ERK1 knockdown, led to more robust suppression of MAPK signaling as seen by RNA-sequencing, qRT-PCR, and Western blot analysis. In addition, treatment with MAPK pathway inhibitors led to gene expression changes that closely resembled those seen upon knockdown of ERK2 but not ERK1. Together, these data demonstrate that ERK2 drives BRAF-mutant melanoma gene expression and proliferation as a function of its higher expression compared with ERK1. Selective inhibition of ERK2 for the treatment of melanomas may spare the toxicity associated with pan-ERK inhibition in normal tissues.
Implications:
BRAF-mutant melanomas overexpress and depend on ERK2 but not ERK1, suggesting that ERK2-selective inhibition may be toxicity sparing.
Data from Transcriptomic Analysis of Diffuse Intrinsic Pontine Glioma (DIPG) Identifies a Targetable ALDH-Positive Subset of Highly Tumorigenic Cancer Stem-like Cells
Authors: Surowiec Rachel K. , Ferris Sarah F. , Apfelbaum April , Espinoza Carlos , Mehta Ranjit K. , Monchamp Karamoja , Sirihorachai Veerin R. , Bedi Karan , Ljungman Mats , Galban Stefanie
Published: April 2023

Abstract
Understanding the cancer stem cell (CSC) landscape in diffuse intrinsic pontine glioma (DIPG) is desperately needed to address treatment resistance and identify novel therapeutic approaches. Patient-derived DIPG cells demonstrated heterogeneous expression of aldehyde dehydrogenase (ALDH) and CD133 by flow cytometry. Transcriptome-level characterization identified elevated mRNA levels of MYC, E2F, DNA damage repair (DDR) genes, glycolytic metabolism, and mTOR signaling in ALDH+ compared with ALDH−, supporting a stem-like phenotype and indicating a druggable target. ALDH+ cells demonstrated increased proliferation, neurosphere formation, and initiated tumors that resulted in decreased survival when orthotopically implanted. Pharmacologic MAPK/PI3K/mTOR targeting downregulated MYC, E2F, and DDR mRNAs and reduced glycolytic metabolism. In vivo PI3K/mTOR targeting inhibited tumor growth in both flank and an ALDH+ orthotopic tumor model likely by reducing cancer stemness. In summary, we describe existence of ALDH+ DIPGs with proliferative properties due to increased metabolism, which may be regulated by the microenvironment and likely contributing to drug resistance and tumor recurrence.
Implications:
Characterization of ALDH+ DIPGs coupled with targeting MAPK/PI3K/mTOR signaling provides an impetus for molecularly targeted therapy aimed at addressing the CSC phenotype in DIPG.
Data from Opposing Effects of Granulocyte Colony-Stimulating Factor on the Initiation and Progression of Breast Cancer Bone Metastases
Authors: Hiraga Toru , Ito Susumu , Mizoguchi Toshihide
Published: April 2023

Abstract
Granulocyte colony stimulating factor (G-CSF), an essential cytokine regulating granulopoiesis, is expressed in a substantial proportion of breast cancers, and it has been implicated in cancer progression. Here, we examined effects of G-CSF on the development of bone metastases of breast cancer using immunocompetent mouse models. The expression of CXC chemokine ligand 12 (CXCL12) in bone marrow stromal cells, which plays a critical role in the maintenance of hematopoietic stem cells and also in cancer cell homing to bone, was markedly decreased in mice treated with G-CSF. Flow cytometric analysis revealed that pretreatment of mice with G-CSF reduced the number of bone-homing cancer cells. G-CSF also increased the population of myeloid-derived suppressor cells (MDSCs) in bone marrow. Depletion of MDSCs using anti–Gr-1 antibody treatment significantly decreased the metastatic tumor burden in bone. The overall effects of G-CSF on bone metastases were finally examined using two different treatment protocols. When mice were treated with G-CSF prior to the tumor cell inoculation, G-CSF did not change bone metastatic-tumor burden. In contrast, when G-CSF treatment was started after the tumor cells had homed to bone, G-CSF significantly accelerated bone metastases formation. These results suggest that G-CSF suppressed cancer cell homing to bone by downregulating CXCL12 expression in bone marrow stromal cells, whereas G-CSF stimulated the progression of bone metastases at least in part by MDSC-mediated mechanisms.
Implications:
G-CSF had opposing effects on the initiation and progression of bone metastases of breast cancer and the balance may regulate the metastatic tumor burden.
Data from The Heme-Regulated Inhibitor Pathway Modulates Susceptibility of Poor Prognosis B-Lineage Acute Leukemia to BH3-Mimetics
Authors: Smith Kaitlyn H. , Budhraja Amit , Lynch John , Roberts Kathryn , Panetta John C. , Connelly Jon P. , Turnis Meghan E. , Pruett-Miller Shondra M. , Schuetz John D. , Mullighan Charles G. , Opferman Joseph T.
Published: April 2023

Abstract
Antiapoptotic MCL1 is one of the most frequently amplified genes in human cancers and elevated expression confers resistance to many therapeutics including the BH3-mimetic agents ABT-199 and ABT-263. The antimalarial, dihydroartemisinin (DHA) translationally represses MCL-1 and synergizes with BH3-mimetics. To explore how DHA represses MCL-1, a genome-wide CRISPR screen identified that loss of genes in the heme synthesis pathway renders mouse BCR-ABL+ B-ALL cells resistant to DHA-induced death. Mechanistically, DHA disrupts the interaction between heme and the eIF2α kinase heme-regulated inhibitor (HRI) triggering the integrated stress response. Genetic ablation of Eif2ak1, which encodes HRI, blocks MCL-1 repression in response to DHA treatment and represses the synergistic killing of DHA and BH3-mimetics compared with wild-type leukemia. Furthermore, BTdCPU, a small-molecule activator of HRI, similarly triggers MCL-1 repression and synergizes with BH3-mimetics in mouse and human leukemia including both Ph+ and Ph-like B-ALL. Finally, combinatorial treatment of leukemia bearing mice with both BTdCPU and a BH3-mimetic extended survival and repressed MCL-1 in vivo. These findings reveal for the first time that the HRI-dependent cellular heme-sensing pathway can modulate apoptosis in leukemic cells by repressing MCL-1 and increasing their responsiveness to BH3-mimetics. This signaling pathway could represent a generalizable mechanism for repressing MCL-1 expression in malignant cells and sensitizing them to available therapeutics.
Implications:
The HRI-dependent cellular heme-sensing pathway can modulate apoptotic sensitivity in leukemic cells by repressing antiapoptotic MCL-1 and increasing their responsiveness to BH3-mimetics.
Data from TSC2 Interacts with HDLBP/Vigilin and Regulates Stress Granule Formation
Authors: Kosmas Kosmas , Filippakis Harilaos , Khabibullin Damir , Turkiewicz Michal , Lam Hilaire C. , Yu Jane , Kedersha Nancy L. , Anderson Paul J. , Henske Elizabeth P.
Published: April 2023

Abstract
Tuberous sclerosis complex (TSC) is caused by mutations of either the TSC1 or TSC2 tumor suppressor gene. TSC causes tumors of the brain, heart, kidney, skin and lymphangioleiomyomatosis (LAM). Here we report that the TSC2 protein physically binds to high-density lipoprotein binding protein (HDLBP), also called vigilin, a core stress granule (SG) protein, and that TSC2 localizes to SGs. SGs contain mRNAs and translation initiation complexes, and regulate gene expression by sequestering specific transcripts, thereby serving a cytoprotective role. TSC2 has never before been shown to localize to SGs and knocking down vigilin impacts SG translocation of TSC2. TSC2-deficient cells showed a striking increase in the number of SGs after thermal shock and arsenite treatment relative to Tsc2-expressing cells. Our findings also show that murine kidney lysates from a model of TSC have increased levels of SG components including G3BP1 and Caprin1. G3BP1 and Caprin are elevated in renal angiomyolipomas (a renal tumor common in patients with TSC) compared with control normal kidney. G3BP1 is also elevated in TSC-associated subependymal giant cell astrocytomas. We found that genetic inhibition of G3BP1 inhibits the proliferation of TSC2-deficient cells in vitro. Finally, in a mouse model of TSC, genetic inhibition of SGs suppresses cell growth, suggesting that targeting SGs may have efficacy in the therapy of TSC.
Implications:
This study demonstrates that TSC2 physically interacts with HDLBP/vigilin, a component of SGs, that TSC2 localizes to SG and that TSC2-deficient cells have more SGs, suggesting that SGs represent a novel therapeutic target in TSC.
Data from Mapping of m6A and Its Regulatory Targets in Prostate Cancer Reveals a METTL3-Low Induction of Therapy Resistance
Authors: Cotter Kellie A. , Gallon John , Uebersax Nadine , Rubin Philip , Meyer Kate D. , Piscuoglio Salvatore , Jaffrey Samie R. , Rubin Mark A.
Published: April 2023

Abstract
Recent evidence has highlighted the role of N6-methyladenosine (m6A) in the regulation of mRNA expression, stability, and translation, supporting a potential role for posttranscriptional regulation mediated by m6A in cancer. Here, we explore prostate cancer as an exemplar and demonstrate that low levels of N6-adenosine-methyltransferase (METTL3) is associated with advanced metastatic disease. To investigate this relationship, we generated the first prostate m6A maps, and further examined how METTL3 regulates expression at the level of transcription, translation, and protein. Significantly, transcripts encoding extracellular matrix proteins are consistently upregulated with METTL3 knockdown. We also examined the relationship between METTL3 and androgen signaling and discovered the upregulation of a hepatocyte nuclear factor–driven gene signature that is associated with therapy resistance in prostate cancer. Significantly, METTL3 knockdown rendered the cells resistant to androgen receptor antagonists via an androgen receptor–independent mechanism driven by the upregulation of nuclear receptor NR5A2/LRH-1.
Implications:
These findings implicate changes in m6A as a mechanism for therapy resistance in metastatic prostate cancer.
Data from Extracellular Matrix–Bound FGF2 Mediates Estrogen Receptor Signaling and Therapeutic Response in Breast Cancer
Authors: DiGiacomo Josh W. , Godet Inês , Trautmann-Rodriguez Michael , Gilkes Daniele M.
Published: April 2023

Abstract
The extracellular matrix (ECM) is often unaccounted for in studies that consider the stromal contribution to cancer cell signaling and response to treatment. To investigate the influence of a fibrotic microenvironment, we use fibroblast-derived ECM scaffolds as a cell culture platform. We uncover that estrogen receptor–positive (ER+) breast cancer cells cultured within ECM-scaffolds have an increase in ER signaling that occurs via an MAPK-dependent, but estrogen-independent manner. The ECM acts as a reservoir by binding, enriching, and presenting growth factors to adjacent epithelial cells. We identified FGF2 as a specific ECM-bound factor that drives ER signaling. ER+ cells cultured on ECM matrices have reduced sensitivity to ER-targeted therapies. The sensitivity to ER-targeted therapy can be restored by inhibiting FGF2–FGFR1 binding. ECM–FGF2 complexes promote Cyclin D1 induction that prevents G1 arrest even in the presence of antiestrogens. This work demonstrates that the ECM can drive ER signaling and resistance to endocrine therapy, and suggests that patients with ER+ breast cancer that have high mammographic breast density may benefit from existing FGFR-targeted therapies.
Implications:
This work uncovers how the ECM may mediate signaling between growth factors and ER+ breast cancer cells to promote estrogen-independent ER signaling and resistance to endocrine therapy.
Data from Stromal CAVIN1 Controls Prostate Cancer Microenvironment and Metastasis by Modulating Lipid Distribution and Inflammatory Signaling
Authors: Low Jin-Yih , Brennen W. Nathaniel , Meeker Alan K. , Ikonen Elina , Simons Brian W. , Laiho Marikki
Published: April 2023

Abstract
Lipid uptake occurs through caveolae, plasma membrane invaginations formed by caveolins (CAV) and caveolae-associated protein 1 (CAVIN1). Genetic alterations of CAV1N1 and CAV1 modify lipid metabolism and underpin lipodystrophy syndromes. Lipids contribute to tumorigenesis by providing fuel to cancer metabolism and supporting growth and signaling. Tumor stroma promotes tumor proliferation, invasion, and metastasis, but how stromal lipids influence these processes remain to be defined. Here, we show that stromal CAVIN1 regulates lipid abundance in the prostate cancer microenvironment and suppresses metastasis. We show that depletion of CAVIN1 in prostate stromal cells markedly reduces their lipid droplet accumulation and increases inflammation. Stromal cells lacking CAVIN1 enhance prostate cancer cell migration and invasion. Remarkably, they increase lipid uptake and M2 inflammatory macrophage infiltration in the primary tumors and metastasis to distant sites. Our data support the concept that stromal cells contribute to prostate cancer aggressiveness by modulating lipid content and inflammation in the tumor microenvironment.
Implications:
This study showed that stromal CAVIN1 suppresses prostate cancer metastasis by modulating tumor microenvironment, lipid content, and inflammatory response.
Data from Heterogeneity and Cancer-Related Features in Lymphangioleiomyomatosis Cells and Tissue
Authors: Espín Roderic , Baiges Alexandra , Blommaert Eline , Herranz Carmen , Roman Antonio , Saez Berta , Ancochea Julio , Valenzuela Claudia , Ussetti Piedad , Laporta Rosalía , Rodríguez-Portal José A. , van Moorsel Coline H.M. , van der Vis Joanne J. , Quanjel Marian J.R. , Villar-Piqué Anna , Diaz-Lucena Daniela , Llorens Franc , Casanova Álvaro , Molina-Molina María , Plass Mireya , Mateo Francesca , Moss Joel , Pujana Miquel Angel
Published: April 2023

Abstract
Lymphangioleiomyomatosis (LAM) is a rare, low-grade metastasizing disease characterized by cystic lung destruction. LAM can exhibit extensive heterogeneity at the molecular, cellular, and tissue levels. However, the molecular similarities and differences among LAM cells and tissue, and their connection to cancer features are not fully understood. By integrating complementary gene and protein LAM signatures, and single-cell and bulk tissue transcriptome profiles, we show sources of disease heterogeneity, and how they correspond to cancer molecular portraits. Subsets of LAM diseased cells differ with respect to gene expression profiles related to hormones, metabolism, proliferation, and stemness. Phenotypic diseased cell differences are identified by evaluating lumican (LUM) proteoglycan and YB1 transcription factor expression in LAM lung lesions. The RUNX1 and IRF1 transcription factors are predicted to regulate LAM cell signatures, and both regulators are expressed in LAM lung lesions, with differences between spindle-like and epithelioid LAM cells. The cancer single-cell transcriptome profiles most similar to those of LAM cells include a breast cancer mesenchymal cell model and lines derived from pleural mesotheliomas. Heterogeneity is also found in LAM lung tissue, where it is mainly determined by immune system factors. Variable expression of the multifunctional innate immunity protein LCN2 is linked to disease heterogeneity. This protein is found to be more abundant in blood plasma from LAM patients than from healthy women.
Implications:
This study identifies LAM molecular and cellular features, master regulators, cancer similarities, and potential causes of disease heterogeneity.
Data from Quantitative Longitudinal Imaging Reveals that Inhibiting Hedgehog Activity Alleviates the Hypoxic Tumor Landscape
Authors: Lama-Sherpa Tshering D. , Das Shamik , Hinshaw Dominique C. , Kammerud Sarah C. , Song Patrick N. , Alsheikh Heba A. , Sorace Anna G. , Samant Rajeev S. , Shevde Lalita A.
Published: April 2023

Abstract
Metastases account for the majority of mortalities related to breast cancer. The onset and sustained presence of hypoxia strongly correlates with increased incidence of metastasis and unfavorable prognosis in patients with breast cancer. The Hedgehog (Hh) signaling pathway is dysregulated in breast cancer, and its abnormal activity enables tumor progression and metastasis. In addition to programming tumor cell behavior, Hh activity enables tumor cells to craft a metastasis-conducive microenvironment. Hypoxia is a prominent feature of growing tumors that impacts multiple signaling circuits that converge upon malignant progression. We investigated the role of Hh activity in crafting a hypoxic environment of breast cancer. We used radioactive tracer [18F]-fluoromisonidazole (FMISO) positron emission tomography (PET) to image tumor hypoxia. We show that tumors competent for Hh activity are able to establish a hypoxic milieu; pharmacologic inhibition of Hh signaling in a syngeneic mammary tumor model mitigates tumor hypoxia. Furthermore, in hypoxia, Hh activity is robustly activated in tumor cells and institutes increased HIF signaling in a VHL-dependent manner. The findings establish a novel perspective on Hh activity in crafting a hypoxic tumor landscape and molecularly navigating the tumor cells to adapt to hypoxic conditions.

Implications: Importantly, we present a translational strategy of utilizing longitudinal hypoxia imaging to measure the efficacy of vismodegib in a preclinical model of triple-negative breast cancer.
Data from Radiomics Biomarkers Correlate with CD8 Expression and Predict Immune Signatures in Melanoma Patients
Authors: Aoude Lauren G. , Wong Bernadette Z.Y. , Bonazzi Vanessa F. , Brosda Sandra , Walters Shaun B. , Koufariotis Lambros T. , Naeini Marjan M. , Pearson John V. , Oey Harald , Patel Kalpana , Bradford Julia J. , Bloxham Conor J. , Atkinson Victoria , Law Phillip , Strutton Geoffrey , Bayley Gerard , Yang Samuel , Smithers B. Mark , Waddell Nicola , Miles Kenneth , Barbour Andrew P.
Published: April 2023

Abstract
Treatment for metastatic melanoma includes targeted and/or immunotherapy. Although many patients respond, only a subset has complete response. As late-stage patients often have multiple tumors in difficult access sites, non-invasive techniques are necessary for the development of predictive/prognostic biomarkers. PET/CT scans from 52 patients with stage III/IV melanoma were assessed and CT image parameters were evaluated as prognostic biomarkers. Analysis indicated patients with high standard deviation or high mean of positive pixels (MPP) had worse progression-free survival (P = 0.00047 and P = 0.0014, respectively) and worse overall survival (P = 0.0223 and P = 0.0465, respectively). Whole-exome sequencing showed high MPP was associated with BRAF mutation status (P = 0.0389). RNA-sequencing indicated patients with immune “cold” signatures had worse survival, which was associated with CT biomarker, MPP4 (P = 0.0284). Multiplex immunofluorescence confirmed a correlation between CD8 expression and image biomarkers (P = 0.0028).
Implications:
CT parameters have the potential to be cost-effective biomarkers of survival in melanoma, and reflect the tumor immune-microenvironment.
Data from SOX9 Defines Distinct Populations of Cells in SHH Medulloblastoma but Is Not Required for Math1-Driven Tumor Formation
Authors: Adolphe Christelle , Millar Amanda , Kojic Marija , Barkauskas Deborah S. , Sundström Anders , Swartling Fredrik J. , Hediyeh-zadeh Soroor , Tan Chin Wee , Davis Melissa J. , Genovesi Laura A. , Wainwright Brandon J.
Published: April 2023

Abstract
Medulloblastoma is the most common malignant pediatric brain tumor and there is an urgent need for molecularly targeted and subgroup-specific therapies. The stem cell factor SOX9, has been proposed as a potential therapeutic target for the treatment of Sonic Hedgehog medulloblastoma (SHH-MB) subgroup tumors, given its role as a downstream target of Hedgehog signaling and in functionally promoting SHH-MB metastasis and treatment resistance. However, the functional requirement for SOX9 in the genesis of medulloblastoma remains to be determined. Here we report a previously undocumented level of SOX9 expression exclusively in proliferating granule cell precursors (GCP) of the postnatal mouse cerebellum, which function as the medulloblastoma-initiating cells of SHH-MBs. Wild-type GCPs express comparatively lower levels of SOX9 than neural stem cells and mature astroglia and SOX9low GCP-like tumor cells constitute the bulk of both infant (Math1Cre:Ptch1lox/lox) and adult (Ptch1LacZ/+) SHH-MB mouse models. Human medulloblastoma single-cell RNA data analyses reveal three distinct SOX9 populations present in SHH-MB and noticeably absent in other medulloblastoma subgroups: SOX9+MATH1+ (GCP), SOX9+GFAP+ (astrocytes) and SOX9+MATH1+GFAP+ (potential tumor-derived astrocytes). To functionally address whether SOX9 is required as a downstream effector of Hedgehog signaling in medulloblastoma tumor cells, we ablated Sox9 using a Math1Cre model system. Surprisingly, targeted ablation of Sox9 in GCPs (Math1Cre:Sox9lox/lox) revealed no overt phenotype and loss of Sox9 in SHH-MB (Math1Cre:Ptch1lox/lox;Sox9lox/lox) does not affect tumor formation.
Implications:
Despite preclinical data indicating SOX9 plays a key role in SHH-MB biology, our data argue against SOX9 as a viable therapeutic target.
Data from Selective ERBB2 and BCL2 Inhibition Is Synergistic for Mitochondrial-Mediated Apoptosis in MDS and AML Cells
Authors: Kam Angel Y.F. , Piryani Sadhna O. , Lee Chang-Lung , Rizzieri David A. , Spector Neil L. , Sarantopoulos Stefanie , Doan Phuong L.
Published: April 2023

Abstract
The ERBB2 proto-oncogene is associated with an aggressive phenotype in breast cancer. Its role in hematologic malignancies is incompletely defined, in part because ERBB2 is not readily detected on the surface of cancer cells. We demonstrate that truncated ERBB2, which lacks the extracellular domain, is overexpressed on primary CD34+ myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) cells compared with healthy hematopoietic cells. This overexpression of ERBB2 is associated with aberrant, oncogenic signaling with autophosphorylation of multiple tyrosine sites. Like in breast cancers, ERBB2 can exist as truncated isoforms p95ERBB2 and p110ERBB2 in MDS and AML. Neutralization of ERBB2 signaling with ERBB2 tyrosine kinase inhibitors (i.e., lapatinib, afatinib, and neratinib) increases apoptotic cell death and reduces human engraftment of MDS cells in mice at 21 weeks posttransplantation. Inhibition of ERBB2 modulates the expression of multiple pro- and anti-apoptotic mitochondrial proteins, including B-cell lymphoma 2 (BCL2). Dual blockade with ERBB2 and BCL2 inhibitors triggers additional reductions of BCL2 phosphorylation and myeloid cell leukemia-1 (MCL1) expression compared with single drug treatment. Dual therapy was synergistic at all tested doses, with a dose reduction index of up to 29 for lapatinib + venetoclax compared with venetoclax alone. Notably, these agents operated together and shifted cancer cells to a pro-apoptotic phenotype, resulting in increased mitochondrial cytochrome c release and activated caspase-3-mediated cell death.
Implications:
These findings warrant study of ERBB2 and BCL2 combination therapy in patients with MDS and AML.
Data from Aberrant Claudin-6–Adhesion Signaling Promotes Endometrial Cancer Progression via Estrogen Receptor α
Authors: Kojima Manabu , Sugimoto Kotaro , Kobayashi Makoto , Ichikawa-Tomikawa Naoki , Kashiwagi Korehito , Watanabe Takafumi , Soeda Shu , Fujimori Keiya , Chiba Hideki
Published: April 2023

Abstract
Cell adhesion proteins not only maintain tissue integrity, but also possess signaling abilities to organize diverse cellular events in a variety of physiologic and pathologic processes; however, the underlying mechanism remains obscure. Among cell adhesion molecules, the claudin (CLDN) family is often aberrantly expressed in various cancers, but the biological relevance and molecular basis for this observation have not yet been established. Here, we show that high CLDN6 expression accelerates cellular proliferation and migration in two distinct human endometrial cancer cell lines in vitro. Using a xenograft model, we also revealed that aberrant CLDN6 expression promotes tumor growth and invasion in endometrial cancer tissues. The second extracellular domain and Y196/200 of CLDN6 were required to recruit and activate Src-family kinases (SFK) and to stimulate malignant phenotypes. Knockout and overexpression of ESR1 in endometrial carcinoma cells showed that the CLDN6-adhesion signal links to estrogen receptor α (ERα) to advance tumor progression. In particular, aberrant CLDN6–ERα signaling contributed to collective cell behaviors in the leading front of endometrial cancer cells. Importantly, we demonstrate that CLDN6/SFK/PI3K-dependent AKT and SGK (serum- and glucocorticoid-regulated kinase) signaling in endometrial cancer cells targets Ser518 in the human ERα to activate ERα transcriptional activity in a ligand-independent manner, thereby promoting tumor progression. Furthermore, CLDN6, at least in part, also regulated gene expression in an ERα-independent manner.
Implications:
The identification of this machinery highlights regulation of the transcription factors by cell adhesion to advance tumor progression.
Data from Platelet-Coated Circulating Tumor Cells Are a Predictive Biomarker in Patients with Metastatic Castrate-Resistant Prostate Cancer
Authors: Chai Shoujie , Matsumoto Nicholas , Storgard Ryan , Peng Chen-Ching , Aparicio Ana , Ormseth Benjamin , Rappard Kate , Cunningham Katherine , Kolatkar Anand , Nevarez Rafael , Tu Kai-Han , Hsu Ching-Ju , Malihi Paymaneh , Corn Paul , Zurita Amado , Hicks James , Kuhn Peter , Ruiz-Velasco Carmen
Published: April 2023

Abstract
Metastatic castration-resistant prostate cancer (mCRPC) includes a subset of patients with particularly unfavorable prognosis characterized by combined defects in at least two of three tumor suppressor genes: PTEN, RB1, and TP53 as aggressive variant prostate cancer molecular signature (AVPC-MS). We aimed to identify circulating tumor cells (CTC) signatures that could inform treatment decisions of patients with mCRPC with cabazitaxel–carboplatin combination therapy versus cabazitaxel alone. Liquid biopsy samples were collected prospectively from 79 patients for retrospective analysis. CTCs were detected, classified, enumerated through a computational pipeline followed by manual curation, and subjected to single-cell genome-wide copy-number profiling for AVPC-MS detection. On the basis of immunofluorescence intensities, detected rare cells were classified into 8 rare-cell groups. Further morphologic characterization categorized CTC subtypes from 4 cytokeratin-positive rare-cell groups, utilizing presence of mesenchymal features and platelet attachment. Of 79 cases, 77 (97.5%) had CTCs, 24 (30.4%) were positive for platelet-coated CTCs (pc.CTCs) and 25 (38.5%) of 65 sequenced patients exhibited AVPC-MS in CTCs. Survival analysis indicated that the presence of pc.CTCs identified the subset of patients who were AVPC-MS–positive with the worst prognosis and minimal benefit from combination therapy. In AVPC-MS–negative patients, its presence showed significant survival improvement from combination therapy. Our findings suggest the presence of pc.CTCs as a predictive biomarker to further stratify AVPC subsets with the worst prognosis and the most significant benefit of additional platinum therapy.
Implications:
HDSCA3.0 can be performed with rare cell detection, categorization, and genomic characterization for pc.CTC identification and AVPC-MS detection as a potential predictive biomarker of mCRPC.
Data from Role of TET1 and 5hmC in an Obesity-Linked Pathway Driving Cancer Stem Cells in Triple-Negative Breast Cancer
Authors: Bao Bin , Teslow Emily A. , Mitrea Cristina , Boerner Julie L. , Dyson Greg , Bollig-Fischer Aliccia
Published: April 2023

Abstract
Triple-negative breast cancer (TNBC) is a subtype of breast cancer that lacks expression of estrogen receptor, progesterone receptor, and the HER2 but is enriched with cancer stem cell–like cells (CSC). CSCs are the fraction of cancer cells recognized as the source of primary malignant tumors that also give rise to metastatic recurrence. 5-Hydroxymethylcytosine (5hmC) is a DNA epigenetic feature derived from 5-methylcytosine by action of tet methylcytosine dioxygenase enzymes (e.g., TET1); and although TET1 and 5hmC are required to maintain embryonic stem cells, the mechanism and role in CSCs remain unknown. Data presented in this report support the conclusion that TET1 and TET1-dependent 5hmC mediate hydrogen peroxide (H2O2)–dependent activation of a novel gene expression cascade driving self-renewal and expansion of CSCs in TNBC. Evidence presented also supports that the H2O2 affecting this pathway arises due to endogenous mechanisms—including downregulation of antioxidant enzyme catalase in TNBC cells—and by exogenous routes, such as systemic inflammation and oxidative stress coupled with obesity, a known risk factor for TNBC incidence and recurrence.
Implications:
This study elucidates a pathway dependent on H2O2 and linked to obesity-driven TNBC tumor-initiating CSCs; thus, it provides new understanding that may advance TNBC prevention and treatment strategies.
Data from p53 Frameshift Mutations Couple Loss-of-Function with Unique Neomorphic Activities
Authors: Tong David R. , Zhou Wen , Katz Chen , Regunath Kausik , Venkatesh Divya , Ihuegbu Chinyere , Manfredi James J. , Laptenko Oleg , Prives Carol
Published: April 2023

Abstract
p53 mutations that result in loss of transcriptional activity are commonly found in numerous types of cancer. While the majority of these are missense mutations that map within the central DNA-binding domain, truncations and/or frameshift mutations can also occur due to various nucleotide substitutions, insertions, or deletions. These changes result in mRNAs containing premature stop codons that are translated into a diverse group of C-terminally truncated proteins. Here we characterized three p53 frameshift mutant proteins expressed from the endogenous TP53 locus in U2OS osteosarcoma and HCT116 colorectal cancer cell lines. These mutants retain intact DNA-binding domains but display altered oligomerization properties. Despite their abnormally high expression levels, they are mostly transcriptionally inactive and unable to initiate a stimuli-induced transcriptional program characteristic of wild-type p53. However, one of these variant p53 proteins, I332fs*14, which resembles naturally expressed TAp53 isoforms β and γ, retains some residual antiproliferative activity and can induce cellular senescence in HCT116 cells. Cells expressing this mutant also display decreased motility in migration assays. Hence, this p53 variant exhibits a combination of loss-of-gain and gain-of-function characteristics, distinguishing it from both wild type p53 and p53 loss.
Implications:
p53 frameshift mutants display a mixture of residual antiproliferative and neomorphic functions that may be differentially exploited for targeted therapy.
Data from Cell-Intrinsic Tumorigenic Functions of PPARγ in Bladder Urothelial Carcinoma
Authors: Sanchez Danielle J. , Missiaen Rindert , Skuli Nicolas , Steger David J. , Simon M. Celeste
Published: April 2023

Abstract
The role of PPAR gamma (PPARγ) has been well characterized in the developmental process of adipogenesis, yet its aberrant expression patterns and functions in cancer subtypes are less understood. Although PPARγ has been recently demonstrated to play non–cell-autonomous roles in promoting bladder urothelial carcinoma (UC) progression, underlying mechanisms of the cell-intrinsic oncogenic activity remain unknown. Here, we report robust expression and nuclear accumulation of PPARγ in 47% of samples of patients with UC, exceeding mRNA expression patterns published by The Cancer Genome Atlas. In vitro assays revealed for the first time that treatment of UC cells with PPARγ inverse agonist or PPARG knockout by CRISPR-Cas9 reduces proliferation, migration, and invasion of multiple established UC cell lines, most strongly in those characterized by PPARG genomic amplification or activating mutations of RXRA, the obligate heterodimer of PPARγ. Through genome-wide approaches including chromatin immunoprecipitation sequencing and RNA sequencing, we define a novel set of PPARγ-regulated genes in UC, including Sonic Hedgehog (SHH). Similar to PPARγ, genetic inhibition of SHH reduces proliferation and motility. Finally, we demonstrate the PPARγ dependency of UC tumors in vivo by genetic and pharmacologic PPARγ inhibition in subcutaneous xenografts. Collectively, our data indicate that PPARγ promotes UC progression in a subset of patients, at least in part, through cell-autonomous mechanisms linked to SHH signaling.
Implications:
Genome-wide analysis of DNA-binding sites for oncogenic factor PPARγ revealed SHH as a novel downstream target involved in UC progression, providing important insight into the tumorigenic nature and molecular mechanism of PPARγ signaling in UC.
Data from Functional Hierarchy and Cooperation of EMT Master Transcription Factors in Breast Cancer Metastasis
Authors: Addison Joseph B. , Voronkova Maria A. , Fugett James H. , Lin Chen-Chung , Linville Nathaniel C. , Trinh Brandon , Livengood Ryan H. , Smolkin Matthew B. , Schaller Michael D. , Ruppert J. Michael , Pugacheva Elena N. , Creighton Chad J. , Ivanov Alexey V.
Published: April 2023

Abstract
Several master transcription factors (TF) can activate the epithelial-to-mesenchymal transition (EMT). However, their individual and combinatorial contributions to EMT in breast cancer are not defined. We show that overexpression of EMT-TFs individually in epithelial cells upregulated endogenous SNAI2, ZEB1/2, TCF4, and TWIST1/2 as a result of positive feedback mediated in part by suppression of their negative regulator miRNAs miR200s/203/205. We identified TCF4 as a potential new target of miR200s. Expression of ZEB1/2 strongly correlated with the mesenchymal phenotype in breast cancer cells, with the CD24−/CD44+ stemness profile, and with lower expression of core epithelial genes in human breast tumors. Knockdown of EMT-TFs identified the key role of ZEB1 and its functional cooperation with other EMT-TFs in the maintenance of the mesenchymal state. Inducible ZEB1+2 knockdown in xenograft models inhibited pulmonary metastasis, emphasizing their critical role in dissemination from primary site and in extravasation. However, ZEB1+2 depletion one-week after intravenous injection did not inhibit lung colonization, suggesting that ZEB1/2 and EMT are not essential for macrometastatic outgrowth. These results provide strong evidence that EMT is orchestrated by coordinated expression of several EMT-TFs and establish ZEB1 as a key master regulator of EMT and metastasis in breast cancer.
Implications:
The EMT program is orchestrated by coordinated expression of multiple EMT transcription factors, whereas ZEB1 integrates the EMT master regulatory network and plays the major role in promoting EMT and metastasis.
Data from High Response Rate and Durability Driven by HLA Genetic Diversity in Patients with Kidney Cancer Treated with Lenvatinib and Pembrolizumab
Authors: Lee Chung-Han , DiNatale Renzo G. , Chowell Diego , Krishna Chirag , Makarov Vladimir , Valero Cristina , Vuong Lynda , Lee Mark , Weiss Kate , Hoen Doug , Morris Luc , Reznik Ed , Murray Samuel , Kotecha Ritesh , Voss Martin H. , Carlo Maria I. , Feldman Darren , Sachdev Pallavi , Adachi Yusuke , Minoshima Yukinori , Matsui Junji , Funahashi Yasuhiro , Nomoto Kenichi , Hakimi A. Ari , Motzer Robert J. , Chan Timothy A.
Published: April 2023

Abstract
Immune checkpoint blockade (ICB) therapy has substantially improved the outcomes of patients with many types of cancers, including renal cell carcinoma (RCC). Initially studied as monotherapy, immunotherapy-based combination regimens have improved the clinical benefit achieved by ICB monotherapy and have revolutionized RCC treatment. While biomarkers like PD-L1 and tumor mutational burden (TMB) are FDA approved as biomarkers for ICB monotherapy, there are no known biomarkers for combination immunotherapies. Here, we describe the clinical outcomes and genomic determinants of response from a phase Ib/II clinical trial on patients with advanced RCC evaluating the efficacy of lenvatinib, a multi-kinase inhibitor mainly targeting VEGFR and FGFR plus pembrolizumab, an anti-PD1 immunotherapy. Concurrent treatment with lenvatinib and pembrolizumab resulted in an objective response rate of 79% (19/24) and tumor shrinkage in 96% (23/24) of patients. While tumor mutational burden (TMB) did not predict for clinical benefit, germline HLA-I diversity strongly impacted treatment efficacy. Specifically, HLA-I evolutionary divergence (HED), which measures the breadth of a patient's immunopeptidome, was associated with both improved clinical benefit and durability of response. Our results identify lenvatinib plus pembrolizumab as a highly active treatment strategy in RCC and reveal HLA-I diversity as a critical determinant of efficacy for this combination. HED also predicted better survival in a separate cohort of patients with RCC following therapy with anti-PD-1–based combination therapy.
Implications:
These findings have substantial implications for RCC therapy and for understanding immunogenetic mechanisms of efficacy and warrants further investigation.
Data from Identification and Characterization of Cancer Cells That Initiate Metastases to the Brain and Other Organs
Authors: Berghoff Anna. S. , Liao Yunxiang , Karreman Matthia A. , Ilhan-Mutlu Ayseguel , Gunkel Katharina , Sprick Martin R. , Eisen Christian , Kessler Tobias , Osswald Matthias , Wünsche Susanne , Feinauer Manuel , Gril Brunhilde , Marmé Frederic , Michel Laura L. , Bago-Horvath Zuszanna , Sahm Felix , Becker Natalia , Breckwoldt Michael O. , Solecki Gergely , Gömmel Miriam , Huang Lulu , Rübmann Petra , Thome Carina M. , Ratliff Miriam , Trumpp Andreas , Steeg Patricia S. , Preusser Matthias , Wick Wolfgang , Winkler Frank
Published: April 2023

Abstract
Specific biological properties of those circulating cancer cells that are the origin of brain metastases (BM) are not well understood. Here, single circulating breast cancer cells were fate-tracked during all steps of the brain metastatic cascade in mice after intracardial injection over weeks. A novel in vivo two-photon microscopy methodology was developed that allowed to determine the specific cellular and molecular features of breast cancer cells that homed in the brain, extravasated, and successfully established a brain macrometastasis. Those BM-initiating breast cancer cells (BMIC) were mainly originating from a slow-cycling subpopulation that included only 16% to 20% of all circulating cancer cells. BMICs showed enrichment of various markers of cellular stemness. As a proof of principle for the principal usefulness of this approach, expression profiling of BMICs versus non-BMICs was performed, which revealed upregulation of NDRG1 in the slow-cycling BMIC subpopulation in one BM model. Here, BM development was completely suppressed when NDRG1 expression was downregulated. In accordance, in primary human breast cancer, NDRG1 expression was heterogeneous, and high NDRG1 expression was associated with shorter metastasis-free survival. In conclusion, our data identify temporary slow-cycling breast cancer cells as the dominant source of brain and other metastases and demonstrates that this can lead to better understanding of BMIC-relevant pathways, including potential new approaches to prevent BM in patients.
Implications:
Cancer cells responsible for successful brain metastasis outgrowth are slow cycling and harbor stemness features. The molecular characteristics of these metastasis-initiating cells can be studied using intravital microscopy technology.
Data from Thyroid Hormone Receptor Beta Induces a Tumor-Suppressive Program in Anaplastic Thyroid Cancer
Authors: Bolf Eric L. , Gillis Noelle E. , Davidson Cole D. , Rodriguez Princess D. , Cozzens Lauren , Tomczak Jennifer A. , Frietze Seth , Carr Frances E.
Published: April 2023

Abstract
The thyroid hormone receptor beta (TRβ), a key regulator of cellular growth and differentiation, is frequently dysregulated in cancers. Diminished expression of TRβ is noted in thyroid, breast, and other solid tumors and is correlated with more aggressive disease. Restoration of TRβ levels decreased tumor growth supporting the concept that TRβ could function as a tumor suppressor. Yet, the TRβ tumor suppression transcriptome is not well delineated and the impact of TRβ is unknown in aggressive anaplastic thyroid cancer (ATC). Here, we establish that restoration of TRβ expression in the human ATC cell line SW1736 (SW-TRβ) reduces the aggressive phenotype, decreases cancer stem cell populations and induces cell death in a T3-dependent manner. Transcriptomic analysis of SW-TRβ cells via RNA sequencing revealed distinctive expression patterns induced by ligand-bound TRβ and revealed novel molecular signaling pathways. Of note, liganded TRβ repressed multiple nodes in the PI3K/AKT pathway, induced expression of thyroid differentiation markers, and promoted proapoptotic pathways. Our results further revealed the JAK1–STAT1 pathway as a novel, T3-mediated, antitumorigenic pathway that can be activated in additional ATC lines. These findings elucidate a TRβ-driven tumor suppression transcriptomic signature, highlight unexplored therapeutic options for ATC, and support TRβ activation as a promising therapeutic option in cancers.
Implications:
TRβ-T3 induced a less aggressive phenotype and tumor suppression program in anaplastic thyroid cancer cells revealing new potential therapeutic targets.
Data from RICTOR Amplification Promotes NSCLC Cell Proliferation through Formation and Activation of mTORC2 at the Expense of mTORC1
Authors: Kim Laura C. , Rhee Christopher H. , Chen Jin
Published: April 2023

Abstract
Non–small cell lung cancer (NSCLC) is characterized by genomic alterations, yet a targetable mutation has not been discovered in nearly half of all patients. Recent studies have identified amplification of RICTOR, an mTORC2-specific cofactor, as a novel actionable target in NSCLC. mTORC2 is one of two distinct mTOR complexes to sense environmental cues and regulate a variety of cellular processes, including cell growth, proliferation, and metabolism, all of which promote tumorigenesis when aberrantly regulated. Interestingly, other components of mTORC2 are not coamplified with RICTOR in human lung cancer, raising the question as to whether RICTOR amplification-induced changes are dependent on mTORC2 function. To model RICTOR amplification, we overexpressed Rictor using the Cas9 Synergistic Activation Mediator system. Overexpression of Rictor increased mTORC2 integrity and signaling, but at the expense of mTORC1, suggesting that overexpressed Rictor recruits common components away from mTORC1. Additionally, Rictor overexpression increases the proliferation and growth of NSCLC 3D cultures and tumors in vivo. Conversely, knockout of RICTOR leads to decreased mTORC2 formation and activity, but increased mTORC1 function. Because Rictor has mTOR-dependent and -independent functions, we also knocked out mLST8, a shared mTOR cofactor but is specifically required for mTORC2 function. Inducible loss of mLST8 in RICTOR-amplified NSCLC cells inhibited mTORC2 integrity and signaling, tumor cell proliferation, and tumor growth. Collectively, these data identify a mechanism for Rictor-driven tumor progression and provide further rationale for the development of an mTORC2-specific inhibitor.
Implications:
RICTOR amplification drives NSCLC proliferation through formation of mTORC2, suggesting mTORC2-specific inhibition could be a beneficial therapeutic option.
Data from MicroRNA-324-5p–CUEDC2 Axis Mediates Gain-of-Function Mutant p53-Driven Cancer Stemness
Authors: Ghatak Dishari , Datta Arindam , Roychowdhury Tanaya , Chattopadhyay Samit , Roychoudhury Susanta
Published: April 2023

Abstract
Regulation of cancer stemness has recently emerged as a new gain-of-function (GOF) property of mutant p53. In this study, we identify miR-324-5p as a critical epigenetic regulator of cancer stemness and demonstrate its role in mediating GOF-mutant p53-driven stemness phenotypes. We report that miR-324–5p is upregulated in human cancer cell lines and non–small cell lung carcinoma (NSCLC) tumors carrying TP53 GOF mutations. Mechanistically, we show that GOF mutant p53 upregulates miR-324–5p expression via c-Myc, an oncogenic transcription factor in cancer cells. Our experimental results suggest that miR-324–5p–induced CSC phenotypes stem from the downregulation of CUEDC2, a downstream target gene of miR-324–5p. Accordingly, CUEDC2 complementation diminishes elevated CSC marker expression in miR-324–5p–overexpressing cancer cells. We further demonstrate that mutant p53 cancer cells maintain a low level of CUEDC2 that is rescued upon miR-324–5p inhibition. Importantly, we identify CUEDC2 downregulation as a novel characteristic feature of TP53-mutated human cancers. We show that activation of NF-κB due to downregulation of CUEDC2 by miR-324–5p imparts stemness in GOF mutant p53 cancer cells. Finally, we provide evidence that TP53 mutations coupled with high miR-324–5p expression predict poor prognosis in patients with lung adenocarcinoma. Thus, our study delineates an altered miR-324–5p-CUEDC2-NF-κB pathway as a novel regulator of GOF mutant p53-driven cancer stemness.
Implications:
Our findings implicate miRNA-324–5p as a novel epigenetic modifier of human cancer stemness.
Data from Progesterone Receptor Is a Haploinsufficient Tumor-Suppressor Gene in Cervical Cancer
Authors: Park Yuri , Baik Seunghan , Ho Charles , Lin Chin-Yo , Chung Sang-Hyuk
Published: April 2023

Abstract
Tumor-suppressor genes (TSG) are often deleted or transcriptionally suppressed in cancer. PGR codes for progesterone receptor (PR), a transcription factor whose function depends on its ligand. Although PR expression is often undetectable in cervical cancer, its relevance to the endocrine-related etiology of this prevalent gynecological disease remains unclear. In this study, we show that the deletion of one Pgr allele in cervical epithelium promoted spontaneous cervical cancer in human papilloma viral oncogene-expressing transgenic mice as efficiently as the ablation of both Pgr alleles. We also show that tumors arising in the transgenic mice with one or both Pgr alleles did not express PR or expressed at the reduced levels compared with the normal epithelium. PR status correlated with estrogen receptor α (ERα) status in the mouse model and the Cancer Genome Atlas (TCGA) dataset. TCGA data analyses revealed that PGR expression significantly decreased in cervical cancer and that the biallelic deletion of PGR was rare. Furthermore, low PGR expression was associated with poor prognosis in young patients with cervical cancer. These discoveries point to PGR as a haploinsufficient TSG in the uterine cervix. They also raise the possibility that the restoration of PGR expression may improve the survival rate.
Implications:
The decreased expression of PR may increase the risk of cervical cancer in human papillomavirus–infected women.
Visual Overview:
http://mcr.aacrjournals.org/content/molcanres/19/1/42/F1.large.jpg.