bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from A Human Organotypic Microfluidic Tumor Model Permits Investigation of the Interplay between Patient-Derived Fibroblasts and Breast Cancer Cells
Authors: Truong Danh D. , Kratz Alexander , Park Jin G. , Barrientos Eric S. , Saini Harpinder , Nguyen Toan , Pockaj Barbara , Mouneimne Ghassan , LaBaer Joshua , Nikkhah Mehdi
Published: March 2024

Abstract
Tumor–stroma interactions significantly influence cancer cell metastasis and disease progression. These interactions are partly comprised of the cross-talk between tumor and stromal fibroblasts, but the key molecular mechanisms within the cross-talk that govern cancer invasion are still unclear. Here, we adapted our previously developed microfluidic device as a 3D in vitro organotypic model to mechanistically study tumor–stroma interactions by mimicking the spatial organization of the tumor microenvironment on a chip. We cocultured breast cancer and patient-derived fibroblast cells in 3D tumor and stroma regions, respectively, and combined functional assessments, including cancer cell migration, with transcriptome profiling to unveil the molecular influence of tumor–stroma cross-talk on invasion. This led to the observation that cancer-associated fibroblasts (CAF) enhanced invasion in 3D by inducing expression of a novel gene of interest, glycoprotein nonmetastatic B (GPNMB), in breast cancer cells, resulting in increased migration speed. Importantly, knockdown of GPNMB blunted the influence of CAF on enhanced cancer invasion. Overall, these results demonstrate the ability of our model to recapitulate patient-specific tumor microenvironments to investigate the cellular and molecular consequences of tumor–stroma interactions.
Significance:
An organotypic model of tumor–stroma interactions on a microfluidic chip reveals that CAFs promote invasion by enhancing expression of GPNMB in breast cancer cells.
Data from HER2 Overexpression Triggers an IL1α Proinflammatory Circuit to Drive Tumorigenesis and Promote Chemotherapy Resistance
Authors: Liu Shou , Lee Ji Shin , Jie Chunfa , Park Min Ho , Iwakura Yoichiro , Patel Yogin , Soni Mithil , Reisman David , Chen Hexin
Published: March 2024

Abstract
Systemic inflammation in breast cancer correlates with poor prognosis, but the molecular underpinnings of this connection are not well understood. In this study, we explored the relationship between HER2 overexpression, inflammation, and expansion of the mammary stem/progenitor and cancer stem–like cell (CSC) population in breast cancer. HER2-positive epithelial cells initiated and sustained an inflammatory milieu needed to promote tumorigenesis. HER2 induced a feedforward activation loop of IL1α and IL6 that stimulated NFκB and STAT3 pathways for generation and maintenance of breast CSC. In mice, Il1a genetic deficiency delayed MMTV-Her2–induced tumorigenesis and reduced inflammatory cytokine expression as well as CSC in primary tumors. In clinical specimens of human breast tumor tissues, tissue microarray analysis revealed a strong positive correlation between IL1α/IL6 expression and CSC-positive phenotype. Pharmacologic blockade of IL1α signaling reduced the CSC population and improved chemotherapeutic efficacy. Our findings suggest new therapeutic or prevention strategies for HER2-positive breast cancers.

Significance: IL1α signaling driven by HER2 promotes chronic inflammation needed to support cancer stem-like cell maintenance in HER2-positive breast cancers. Cancer Res; 78(8); 2040–51. ©2018 AACR.
Data from SIX2 Mediates Late-Stage Metastasis via Direct Regulation of SOX2 and Induction of a Cancer Stem Cell Program
Authors: Oliphant Michael U.J. , Vincent Melanie Y. , Galbraith Matthew D. , Pandey Ahwan , Zaberezhnyy Vadym , Rudra Pratyaydipta , Johnson Katherine R. , Costello James C. , Ghosh Debashis , DeGregori James , Espinosa Joaquin M. , Ford Heide L.
Published: March 2024

Abstract
The capacity for tumor cells to metastasize efficiently is directly linked to their ability to colonize secondary sites. Here we identify Six2, a developmental transcription factor, as a critical regulator of a breast cancer stem cell program that enables metastatic colonization. In several triple-negative breast cancer (TNBC) models, Six2 enhanced the expression of genes associated with embryonic stem cell programs. Six2 directly bound the Sox2 Srr2 enhancer, promoting Sox2 expression and downstream expression of Nanog, which are both key pluripotency factors. Regulation of Sox2 by Six2 enhanced cancer stem cell properties and increased metastatic colonization. Six2 and Sox2 expression correlated highly in breast cancers including TNBC, where a Six2 expression signature was predictive of metastatic burden and poor clinical outcome. Our findings demonstrate that a SIX2/SOX2 axis is required for efficient metastatic colonization, underscoring a key role for stemness factors in outgrowth at secondary sites.
Significance:
These findings provide novel mechanistic insight into stemness and the metastatic outgrowth of triple-negative breast cancer cells.
Data from Inactivation of Proprotein Convertases in T Cells Inhibits PD-1 Expression and Creates a Favorable Immune Microenvironment in Colorectal Cancer
Authors: Tomé Mercedes , Pappalardo Angela , Soulet Fabienne , López José Javier , Olaizola Jone , Leger Yannick , Dubreuil Marielle , Mouchard Amandine , Fessart Delphine , Delom Frédéric , Pitard Vincent , Bechade Dominique , Fonck Mariane , Rosado Juan Antonio , Ghiringhelli François , Déchanet-Merville Julie , Soubeyran Isabelle , Siegfried Geraldine , Evrard Serge , Khatib Abdel-Majid
Published: March 2024

Abstract
Proprotein convertases (PC) activate precursor proteins that play crucial roles in various cancers. In this study, we investigated whether PC enzyme activity is required for expression of the checkpoint protein programmed cell death protein 1 (PD-1) on cytotoxic T lymphocytes (CTL) in colon cancer. Although altered expression of the PC secretory pathway was observed in human colon cancers, only furin showed highly diffuse expression throughout the tumors. Inhibition of PCs in T cells using the general protein-based inhibitor α1-PDX or the pharmacologic inhibitor Decanoyl-Arg-Val-Lys-Arg-chloromethylketone repressed PD-1 and exhausted CTLs via induction of T-cell proliferation and apoptosis inhibition, which improved CTL efficacy against microsatellite instable and microsatellite stable colon cancer cells. In vivo, inhibition of PCs enhanced CTL infiltration in colorectal tumors and increased tumor clearance in syngeneic mice compared with immunodeficient mice. Inhibition of PCs repressed PD-1 expression by blocking proteolytic maturation of the Notch precursor, inhibiting calcium/NFAT and NF-κB signaling, and enhancing ERK activation. These findings define a key role for PCs in regulating PD-1 expression and suggest targeting PCs as an adjunct approach to colorectal tumor immunotherapy.
Significance:
Protein convertase enzymatic activity is required for PD-1 expression on T cells, and inhibition of protein convertase improves T-cell targeting of microsatellite instable and stable colorectal cancer.
Data from DAXX Suppresses Tumor-Initiating Cells in Estrogen Receptor–Positive Breast Cancer Following Endocrine Therapy
Authors: Peiffer Daniel S. , Wyatt Debra , Zlobin Andrei , Piracha Ali , Ng Jeffrey , Dingwall Andrew K. , Albain Kathy S. , Osipo Clodia
Published: March 2024

Abstract
Estrogen receptor (ER)-positive breast cancer recurrence is thought to be driven by tumor-initiating cells (TIC). TICs are enriched by endocrine therapy through NOTCH signaling. Side effects have limited clinical trial testing of NOTCH-targeted therapies. Death-associated factor 6 (DAXX) is a newly identified marker whose RNA expression inversely correlates with NOTCH in human ER+ breast tumor samples. In this study, knockdown and overexpression approaches were used to investigate the role of DAXX on stem/pluripotent gene expression, TIC survival in vitro, and TIC frequency in vivo, and the mechanism by which DAXX suppresses TICs in ER+ breast cancer. 17β-Estradiol (E2)-mediated ER activation stabilized the DAXX protein, which was required for repressing stem/pluripotent genes (NOTCH4, SOX2, OCT4, NANOG, and ALDH1A1), and TICs in vitro and in vivo. Conversely, endocrine therapy promoted rapid protein depletion due to increased proteasome activity. DAXX was enriched at promoters of stem/pluripotent genes, which was lost with endocrine therapy. Ectopic expression of DAXX decreased stem/pluripotent gene transcripts to levels similar to E2 treatment. DAXX-mediated repression of stem/pluripotent genes and suppression of TICs was dependent on DNMT1. DAXX or DNMT1 was necessary to inhibit methylation of CpGs within the SOX2 promoter and moderately within the gene body of NOTCH4, NOTCH activation, and TIC survival. E2-mediated stabilization of DAXX was necessary and sufficient to repress stem/pluripotent genes by recruiting DNMT1 to methylate some promoters and suppress TICs. These findings suggest that a combination of endocrine therapy and DAXX-stabilizing agents may inhibit ER+ tumor recurrence.
Significance:
Estradiol-mediated stabilization of DAXX is necessary and sufficient to repress genes associated with stemness, suggesting that the combination of endocrine therapy and DAXX-stabilizing agents may inhibit tumor recurrence in ER+ breast cancer.
Data from Follistatin-like Protein 1 Inhibits Lung Cancer Metastasis by Preventing Proteolytic Activation of Osteopontin
Authors: Chiou Jean , Chang Yu-Chan , Tsai Hsing-Fang , Lin Yuan-Feng , Huang Ming-Shyan , Yang Chih-Jen , Hsiao Michael
Published: March 2024

Abstract
Follistatin-like protein 1 (FSTL1) plays a critical role in lung organogenesis, but is downregulated during lung cancer development and progression. The prognostic significance and functional consequences of FSTL1 downregulation in lung cancer are unclear. Here, reduced levels of FSTL1 were detected in various tumors compared with normal tissues and were associated with poor clinical outcome in patients with non–small cell lung cancer, particularly those with lung adenocarcinoma. FSTL1 expression negatively correlated with the metastatic potential of lung cancer cells. Antibody-based neutralization of extracellular FSTL1 increased cellular migration/invasion while addition of recombinant FSTL1 protein diminished the metastatic capacity of lung cancer cells in vitro and in vivo. Notably, treatment with FSTL1 effectively prevented the metastatic progression of lung cancer cells in an orthotopic animal model. Mechanistically, FSTL1 directly bound to the proform of secreted phosphoprotein 1 (SPP1)/osteopontin, restraining proteolytic activation of SPP1, which led to inactivation of integrin/CD44-associated signaling and rearrangement of the actin cytoskeleton. Combined low expression of FSTL1 and high expression of SPP1 predicted a poorer prognosis for patients with lung cancer. This study highlights the novel interaction between FSTL1 and SPP1 and new opportunities to effectively target SPP1-driven metastatic cancers characterized by FSTL1 downregulation.
Significance:
These findings describe the novel interaction between FSTL1 and SPP1 and its role in the metastatic progression of lung adenocarcinoma.
Data from A ceRNA Circuitry Involving the Long Noncoding RNA Klhl14-AS, Pax8, and Bcl2 Drives Thyroid Carcinogenesis
Authors: Credendino Sara C. , Bellone Maria L. , Lewin Nicole , Amendola Elena , Sanges Remo , Basu Swaraj , Sepe Romina , Decaussin-Petrucci Myriam , Tinto Nadia , Fusco Alfredo , De Felice Mario , De Vita Gabriella
Published: March 2024

Abstract
Klhl14-AS is a long noncoding RNA expressed since early specification of thyroid bud and is the most enriched gene in the mouse thyroid primordium at E10.5. Here, we studied its involvement in thyroid carcinogenesis by analyzing its expression in cancer tissues and different models of neoplastic transformation. Compared with normal thyroid tissue and cells, Klhl14-AS was significantly downregulated in human thyroid carcinoma tissue specimens, particularly the anaplastic histotype, thyroid cancer cell lines, and rodent models of thyroid cancer. Downregulating the expression of Klhl14-AS in normal thyroid cells decreased the expression of thyroid differentiation markers and cell death and increased cell viability. These effects were mediated by the binding of Klhl14-AS to two miRNAs, Mir182-5p and Mir20a-5p, which silenced Pax8 and Bcl2, both essential players of thyroid differentiation. MIR182-5p and MIR20a-5p were upregulated in human thyroid cancer and thyroid cancer experimental models and their effects on Pax8 and Bcl2 were rescued by Klhl14-AS overexpression, confirming Klhl14-AS as a ceRNA for both Pax8 and Bcl2. This work connects deregulation of differentiation with increased proliferation and survival in thyroid neoplastic cells and highlights a novel ceRNA circuitry involving key regulators of thyroid physiology.
Significance:
This study describes a new ceRNA with potential tumor suppression activity and helps us better understand the regulatory mechanisms during thyroid differentiation and carcinogenesis.
Data from Randomly Distributed K14+ Breast Tumor Cells Polarize to the Leading Edge and Guide Collective Migration in Response to Chemical and Mechanical Environmental Cues
Authors: Hwang Priscilla Y. , Brenot Audrey , King Ashley C. , Longmore Gregory D. , George Steven C.
Published: March 2024

Abstract
Collective cell migration is an adaptive, coordinated interactive process involving cell–cell and cell–extracellular matrix (ECM) microenvironmental interactions. A critical aspect of collective migration is the sensing and establishment of directional movement. It has been proposed that a subgroup of cells known as leader cells localize at the front edge of a collectively migrating cluster and are responsible for directing migration. However, it is unknown how and when leader cells arrive at the front edge and what environmental cues dictate leader cell development and behavior. Here, we addressed these questions by combining a microfluidic device design that mimics multiple tumor microenvironmental cues concurrently with biologically relevant primary, heterogeneous tumor cell organoids. Prior to migration, breast tumor leader cells (K14+) were present throughout a tumor organoid and migrated (polarized) to the leading edge in response to biochemical and biomechanical cues. Impairment of either CXCR4 (biochemical responsive) or the collagen receptor DDR2 (biomechanical responsive) abrogated polarization of leader cells and directed collective migration. This work demonstrates that K14+ leader cells utilize both chemical and mechanical cues from the microenvironment to polarize to the leading edge of collectively migrating tumors.
Significance:
These findings demonstrate that pre-existing, randomly distributed leader cells within primary tumor organoids use CXCR4 and DDR2 to polarize to the leading edge and direct migration.
Data from Tumor-Derived Prostaglandin E2 Promotes p50 NF-κB-Dependent Differentiation of Monocytic MDSCs
Authors: Porta Chiara , Consonni Francesca Maria , Morlacchi Sara , Sangaletti Sabina , Bleve Augusto , Totaro Maria Grazia , Larghi Paola , Rimoldi Monica , Tripodo Claudio , Strauss Laura , Banfi Stefania , Storto Mariangela , Pressiani Tiziana , Rimassa Lorenza , Tartari Silvia , Ippolito Alessandro , Doni Andrea , Soldà Giulia , Duga Stefano , Piccolo Viviana , Ostuni Renato , Natoli Gioacchino , Bronte Vincenzo , Balzac Fiorella , Turco Emilia , Hirsch Emilio , Colombo Mario P. , Sica Antonio
Published: March 2024

Abstract
Myeloid-derived suppressor cells (MDSC) include immature monocytic (M-MDSC) and granulocytic (PMN-MDSC) cells that share the ability to suppress adaptive immunity and to hinder the effectiveness of anticancer treatments. Of note, in response to IFNγ, M-MDSCs release the tumor-promoting and immunosuppressive molecule nitric oxide (NO), whereas macrophages largely express antitumor properties. Investigating these opposing activities, we found that tumor-derived prostaglandin E2 (PGE2) induces nuclear accumulation of p50 NF-κB in M-MDSCs, diverting their response to IFNγ toward NO-mediated immunosuppression and reducing TNFα expression. At the genome level, p50 NF-κB promoted binding of STAT1 to regulatory regions of selected IFNγ-dependent genes, including inducible nitric oxide synthase (Nos2). In agreement, ablation of p50 as well as pharmacologic inhibition of either the PGE2 receptor EP2 or NO production reprogrammed M-MDSCs toward a NOS2low/TNFαhigh phenotype, restoring the in vivo antitumor activity of IFNγ. Our results indicate that inhibition of the PGE2/p50/NO axis prevents MDSC-suppressive functions and restores the efficacy of anticancer immunotherapy.
Significance:
Tumor-derived PGE2-mediated induction of nuclear p50 NF-κB epigenetically reprograms the response of monocytic cells to IFNγ toward an immunosuppressive phenotype, thus retrieving the anticancer properties of IFNγ.
Data from Infiltrating Mast Cell–Mediated Stimulation of Estrogen Receptor Activity in Breast Cancer Cells Promotes the Luminal Phenotype
Authors: Majorini Maria Teresa , Cancila Valeria , Rigoni Alice , Botti Laura , Dugo Matteo , Triulzi Tiziana , De Cecco Loris , Fontanella Enrico , Jachetti Elena , Tagliabue Elda , Chiodoni Claudia , Tripodo Claudio , Colombo Mario P. , Lecis Daniele
Published: March 2024

Abstract
Tumor growth and development is determined by both cancer cell–autonomous and microenvironmental mechanisms, including the contribution of infiltrating immune cells. Because the role of mast cells (MC) in this process is poorly characterized and even controversial, we investigated their part in breast cancer. Crossing C57BL/6 MMTV-PyMT mice, which spontaneously develop mammary carcinomas, with MC-deficient C57BL/6-KitW-sh/W-sh (Wsh) mice, showed that MCs promote tumor growth and prevent the development of basal CK5-positive areas in favor of a luminal gene program. When cocultured with breast cancer cells in vitro, MCs hindered activation of cMET, a master regulator of the basal program, and simultaneously promoted expression and activation of estrogen receptor (ESR1/ER) and its target genes (PGR, KRT8/CK8, BCL2), which are all luminal markers. Moreover, MCs reduced ERBB2/HER2 levels, whose inhibition further increased ESR1 expression. In vivo and in silico analysis of patients with breast cancer revealed a direct correlation between MC density and ESR1 expression. In mice engrafted with HER2-positive breast cancer tumors, coinjection of MCs increased tumor engraftment and outgrowth, supporting the link between MCs and increased risk of relapse in patients with breast cancer. Together, our findings support the notion that MCs influence the phenotype of breast cancer cells by stimulating a luminal phenotype and ultimately modifying the outcome of the disease.
Significance:
Mast cells impact breast cancer outcome by directly affecting the phenotype of tumor cells through stimulation of the estrogen receptor pathway.
Data from Induction of DNMT3B by PGE2 and IL6 at Distant Metastatic Sites Promotes Epigenetic Modification and Breast Cancer Colonization
Authors: So Jae Young , Skrypek Nicolas , Yang Howard H. , Merchant Anand S. , Nelson George W. , Chen Wei-Dong , Ishii Hiroki , Chen Jennifer M. , Hu Gangqing , Achyut Bhagelu R. , Yoon Esther C. , Han Liying , Huang Chuanshu , Cam Margaret C. , Zhao Keji , Lee Maxwell P. , Yang Li
Published: March 2024

Abstract
Current cancer treatments are largely based on the genetic characterization of primary tumors and are ineffective for metastatic disease. Here we report that DNA methyltransferase 3B (DNMT3B) is induced at distant metastatic sites and mediates epigenetic reprogramming of metastatic tumor cells. Multiomics analysis and spontaneous metastatic mouse models revealed that DNMT3B alters multiple pathways including STAT3, NFκB, PI3K/Akt, β-catenin, and Notch signaling, which are critical for cancer cell survival, apoptosis, proliferation, invasion, and colonization. PGE2 and IL6 were identified as critical inflammatory mediators in DNMT3B induction. DNMT3B expression levels positively correlated with human metastatic progression. Targeting IL6 or COX-2 reduced DNMT3B induction and improved chemo or PD1 therapy. We propose a novel mechanism linking the metastatic microenvironment with epigenetic alterations that occur at distant sites. These results caution against the “Achilles heel” in cancer therapies based on primary tumor characterization and suggests targeting DNMT3B induction as new option for treating metastatic disease.
Significance:
These findings reveal that DNMT3B epigenetically regulates multiple pro-oncogenic signaling pathways via the inflammatory microenvironment at distant sites, cautioning the clinical approach basing current therapies on genetic characterization of primary tumors.
Data from Melanoma-Secreted Lysosomes Trigger Monocyte-Derived Dendritic Cell Apoptosis and Limit Cancer Immunotherapy
Authors: Santana-Magal Nadine , Farhat-Younis Leen , Gutwillig Amit , Gleiberman Annette , Rasoulouniriana Diana , Tal Lior , Netanely Dvir , Shamir Ron , Blau Rachel , Feinmesser Meora , Zlotnik Oran , Gutman Haim , Linde Ian L. , Reticker-Flynn Nathan E. , Rider Peleg , Carmi Yaron
Published: March 2024

Abstract
The recent success of checkpoint blockade therapies has established immunotherapy as one of the most promising treatments for melanoma. Nonetheless, a complete curative response following immunotherapy is observed only in a fraction of patients. To identify what factors limit the efficacy of immunotherapies, we established mouse models that cease to respond to immunotherapies once their tumors exceed a certain stage. Analysis of the immune systems of the organisms revealed that the numbers of tumor-infiltrating dendritic cells (TIDC) drastically decreased with time. Further, in contrast to the current paradigm, once melanoma was established, TIDC did not migrate into sentinel lymph nodes. Instead, they underwent local cell death due to excessive phagocytosis of lysosomes. Importantly, TIDC were required to license the cytotoxic activity of tumor CD8+ T cells, and in their absence, T cells did not lyse melanoma cells. Our results offer a paradigm shift regarding the role of TIDC and a framework to increase the efficacy of immunotherapies.
Significance:
This work redefines the role of monocyte-derived dendritic cells in melanoma and provides a novel strategy to increase the efficacy of T-cell–based immunotherapies in nonresponding individuals.
Data from Resistance to MAPK Inhibitors in Melanoma Involves Activation of the IGF1R–MEK5–Erk5 Pathway
Authors: Benito-Jardón Lucía , Díaz-Martínez Marta , Arellano-Sánchez Nohemi , Vaquero-Morales Paloma , Esparís-Ogando Azucena , Teixidó Joaquin
Published: March 2024

Abstract
Combined treatment of metastatic melanoma with BRAF and MEK inhibitors has improved survival, but the emergence of resistance represents an important clinical challenge. Targeting ERK is a suitable strategy currently being investigated in melanoma and other cancers. To anticipate possible resistance to ERK inhibitors (ERKi), we used SCH772984 (SCH) as a model ERKi to characterize resistance mechanisms in two BRAF V600E melanoma cell lines. The ERKi-resistant cells were also resistant to vemurafenib (VMF), trametinib (TMT), and combined treatment with either VMF and SCH or TMT and SCH. Resistance to SCH involved stimulation of the IGF1R–MEK5–Erk5 signaling pathway, which counteracted inhibition of Erk1/2 activation and cell growth. Inhibition of IGF1R with linsitinib blocked Erk5 activation in SCH-resistant cells and decreased their growth in 3D spheroid growth assays as well as in NOD scid gamma (NSG) mice. Cells doubly resistant to VMF and TMT or to VMF and SCH also exhibited downregulated Erk1/2 activation linked to stimulation of the IGF1R–MEK5–Erk5 pathway, which accounted for resistance. In addition, we found that the decreased Erk1/2 activation in SCH-resistant cells involved reduced expression and function of TGFα. These data reveal an escape signaling route that melanoma cells use to bypass Erk1/2 blockade during targeted melanoma treatment and offer several possible targets whose disruption may circumvent resistance.
Significance:
Activation of the IGF1R–MEK5–Erk5 signaling pathway opposes pharmacologic inhibition of Erk1/2 in melanoma, leading to the reactivation of cell proliferation and acquired resistance.
Data from ATM Loss Confers Greater Sensitivity to ATR Inhibition Than PARP Inhibition in Prostate Cancer
Authors: Rafiei Shahrzad , Fitzpatrick Kenyon , Liu David , Cai Mu-Yan , Elmarakeby Haitham A. , Park Jihye , Ricker Cora , Kochupurakkal Bose S. , Choudhury Atish D. , Hahn William C. , Balk Steven P. , Hwang Justin H. , Van Allen Eliezer M. , Mouw Kent W.
Published: March 2024

Abstract
Alterations in DNA damage response (DDR) genes are common in advanced prostate tumors and are associated with unique genomic and clinical features. ATM is a DDR kinase that has a central role in coordinating DNA repair and cell-cycle response following DNA damage, and ATM alterations are present in approximately 5% of advanced prostate tumors. Recently, inhibitors of PARP have demonstrated activity in advanced prostate tumors harboring DDR gene alterations, particularly in tumors with BRCA1/2 alterations. However, the role of alterations in DDR genes beyond BRCA1/2 in mediating PARP inhibitor sensitivity is poorly understood. To define the role of ATM loss in prostate tumor DDR function and sensitivity to DDR-directed agents, we created a series of ATM-deficient preclinical prostate cancer models and tested the impact of ATM loss on DNA repair function and therapeutic sensitivities. ATM loss altered DDR signaling, but did not directly impact homologous recombination function. Furthermore, ATM loss did not significantly impact sensitivity to PARP inhibition but robustly sensitized to inhibitors of the related DDR kinase ATR. These results have important implications for planned and ongoing prostate cancer clinical trials and suggest that patients with tumor ATM alterations may be more likely to benefit from ATR inhibitor than PARP inhibitor therapy.
Significance:
ATM loss occurs in a subset of prostate tumors. This study shows that deleting ATM in prostate cancer models does not significantly increase sensitivity to PARP inhibition but does sensitize to ATR inhibition.

See related commentary by Setton and Powell, p. 2085
Data from TET2-Dependent Hydroxymethylome Plasticity Reduces Melanoma Initiation and Progression
Authors: Bonvin Elise , Radaelli Enrico , Bizet Martin , Luciani Flavie , Calonne Emilie , Putmans Pascale , Nittner David , Singh Nitesh Kumar , Santagostino Sara Francesca , Petit Valérie , Larue Lionel , Marine Jean Christophe , Fuks François
Published: March 2024

Abstract
Although numerous epigenetic aberrancies accumulate in melanoma, their contribution to initiation and progression remain unclear. The epigenetic mark 5-hydroxymethylcytosine (5hmC), generated through TET-mediated DNA modification, is now referred to as the sixth base of DNA and has recently been reported as a potential biomarker for multiple types of cancer. Loss of 5hmC is an epigenetic hallmark of melanoma, but whether a decrease in 5hmc levels contributes directly to pathogenesis or whether it merely results from disease progression–associated epigenetic remodeling remains to be established. Here, we show that NRAS-driven melanomagenesis in mice is accompanied by an overall decrease in 5hmC and specific 5hmC gains in selected gene bodies. Strikingly, genetic ablation of Tet2 in mice cooperated with oncogenic NRASQ61K to promote melanoma initiation while suppressing specific gains in 5hmC. We conclude that TET2 acts as a barrier to melanoma initiation and progression, partly by promoting 5hmC gains in specific gene bodies.
Significance:
This work emphasizes the importance of epigenome plasticity in cancer development and highlights the involvement of druggable epigenetic factors in cancer.
Data from STING Promotes Homeostasis via Regulation of Cell Proliferation and Chromosomal Stability
Authors: Ranoa Diana Rose E. , Widau Ryan C. , Mallon Stephen , Parekh Akash D. , Nicolae Claudia M. , Huang Xiaona , Bolt Michael J. , Arina Ainhoa , Parry Renate , Kron Stephen J. , Moldovan George-Lucian , Khodarev Nikolai N. , Weichselbaum Ralph R.
Published: March 2024

Abstract
Given the integral role of stimulator of interferon genes (STING, TMEM173) in the innate immune response, its loss or impairment in cancer is thought to primarily affect antitumor immunity. Here we demonstrate a role for STING in the maintenance of cellular homeostasis through regulation of the cell cycle. Depletion of STING in human and murine cancer cells and tumors resulted in increased proliferation compared with wild-type controls. Microarray analysis revealed genes involved in cell-cycle regulation are differentially expressed in STINGko compared with WT MEFs. STING-mediated regulation of the cell cycle converged on NFκB- and p53-driven activation of p21. The absence of STING led to premature activation of cyclin-dependent kinase 1 (CDK1), early onset to S-phase and mitosis, and increased chromosome instability, which was enhanced by ionizing radiation. These results suggest a pivotal role for STING in maintaining cellular homeostasis and response to genotoxic stress.
Significance:
These findings provide clear mechanistic understanding of the role of STING in cell-cycle regulation, which may be exploited in cancer therapy because most normal cells express STING, while many tumor cells do not.

See related commentary by Gius and Zhu, p. 1295
Data from Antibody-Mediated Endocytosis of Polysialic Acid Enables Intracellular Delivery and Cytotoxicity of a Glycan-Directed Antibody–Drug Conjugate
Authors: Cox Emily C. , Thornlow Dana N. , Jones Michaela A. , Fuller Jordan L. , Merritt Judith H. , Paszek Matthew J. , Alabi Christopher A. , DeLisa Matthew P.
Published: March 2024

Abstract
The specific targeting of differentially expressed glycans in malignant cells has emerged as an attractive anticancer strategy. One such target is the oncodevelopmental antigen polysialic acid (polySia), a polymer of α2,8-linked sialic acid residues that is largely absent during postnatal development but is re-expressed during progression of several malignant human tumors, including small-cell and non–small cell lung carcinomas, glioma, neuroblastoma, and pancreatic carcinoma. In these cancers, expression of polySia correlates with tumor progression and poor prognosis and appears to modulate cancer cell adhesion, invasiveness, and metastasis. To evaluate the potential of PolySia as a target for anticancer therapy, we developed a chimeric human polySia-specific mAb that retained low nanomolar (nmol/L) target affinity and exhibited exquisite selectivity for polySia structures. The engineered chimeric mAb recognized several polySia-positive tumor cell lines in vitro and induced rapid endocytosis of polySia antigens. To determine whether this internalization could be exploited for delivery of conjugated cytotoxic drugs, we generated an antibody–drug conjugate (ADC) by covalently linking the chimeric human mAb to the tubulin-binding maytansinoid DM1 using a bioorthogonal chemical reaction scheme. The resulting polySia-directed ADC demonstrated potent target-dependent cytotoxicity against polySia-positive tumor cells in vitro. Collectively, these results establish polySia as a valid cell-surface, cancer-specific target for glycan-directed ADC and contribute to a growing body of evidence that the tumor glycocalyx is a promising target for synthetic immunotherapies.
Significance:
These findings describe a glycan-specific antibody-drug conjugate that establishes polySia as a viable cell surface target within the tumor glycocalyx.
Data from PSF Promotes ER-Positive Breast Cancer Progression via Posttranscriptional Regulation of ESR1 and SCFD2
Authors: Mitobe Yuichi , Iino Kaori , Takayama Ken-ichi , Ikeda Kazuhiro , Suzuki Takashi , Aogi Kenjiro , Kawabata Hidetaka , Suzuki Yutaka , Horie-Inoue Kuniko , Inoue Satoshi
Published: March 2024

Abstract
Endocrine therapy is standard treatment for estrogen receptor (ER)-positive breast cancer, yet long-term treatment often causes acquired resistance, which results in recurrence and metastasis. Recent studies have revealed that RNA-binding proteins (RBP) are involved in tumorigenesis. Here, we demonstrate that PSF/SFPQ is an RBP that potentially predicts poor prognosis of patients with ER-positive breast cancer by posttranscriptionally regulating ERα (ESR1) mRNA expression. Strong PSF immunoreactivity correlated with shorter overall survival in patients with ER-positive breast cancer. PSF was predominantly expressed in a model of tamoxifen-resistant breast cancer cells, and depletion of PSF attenuated proliferation of cultured cells and xenografted tumors. PSF expression was significantly associated with estrogen signaling. PSF siRNA downregulated ESR1 mRNA by inhibiting nuclear export of the RNA. Integrative analyses of microarray and RNA immunoprecipitation sequencing also identified SCFD2, TRA2B, and ASPM as targets of PSF. Among the PSF targets, SCFD2 was a poor prognostic indicator of breast cancer and SCFD2 knockdown significantly suppressed breast cancer cell proliferation. Collectively, this study shows that PSF plays a pathophysiologic role in ER-positive breast cancer by posttranscriptionally regulating expression of its target genes such as ESR1 and SCFD2. Overall, PSF and SCFD2 could be potential diagnostic and therapeutic targets for primary and hormone-refractory breast cancers.
Significance:
This study defines oncogenic roles of RNA-binding protein PSF, which exhibits posttranscriptional regulation in ER-positive breast cancer.
Data from Loss of Apc Rapidly Impairs DNA Methylation Programs and Cell Fate Decisions in Lgr5+ Intestinal Stem Cells
Authors: Bruschi Marco , Garnier Laure , Cleroux Elouan , Giordano Alicia , Dumas Michael , Bardet Anaïs F. , Kergrohen Thomas , Quesada Stanislas , Cesses Pierre , Weber Michael , Gerbe François , Jay Philippe
Published: March 2024

Abstract
Colorectal cancer initiation and progression result from the accumulation of genetic and epigenetic alterations. Although aberrant gene expression and DNA methylation profiles are considered hallmarks of colorectal cancer development, the precise timing at which these are produced during tumor establishment remains elusive. Here we investigated the early transcriptional and epigenetic changes induced by adenomatous polyposis coli (Apc) inactivation in intestinal crypts. Hyperactivation of the Wnt pathway via Apc inactivation in crypt base columnar intestinal stem cells (ISC) led to their rapid accumulation driven by an impaired molecular commitment to differentiation, which was associated with discrete alterations in DNA methylation. Importantly, inhibiting the enzymes responsible for de novo DNA methylation restored the responsiveness of Apc-deficient intestinal organoids to stimuli regulating the proliferation-to-differentiation transition in ISC. This work reveals that early DNA methylation changes play critical roles in the establishment of the impaired fate decision program consecutive to Apc loss of function.
Significance:
This study demonstrates the functional impact of changes in DNA methylation to determine the colorectal cancer cell phenotype following loss of Apc function.
Data from Retrodifferentiation of Human Tumor Hepatocytes to Stem Cells Leads to Metabolic Reprogramming and Chemoresistance
Authors: Fekir Karim , Dubois-Pot-Schneider Hélène , Désert Romain , Daniel Yoann , Glaise Denise , Rauch Claudine , Morel Fabrice , Fromenty Bernard , Musso Orlando , Cabillic Florian , Corlu Anne
Published: March 2024

Abstract
Human hepatocellular carcinoma (HCC) heterogeneity promotes recurrence and therapeutic resistance. We recently demonstrated that inflammation favors hepatocyte retrodifferentiation into progenitor cells. Here, we identify the molecular effectors that induce metabolic reprogramming, chemoresistance, and invasiveness of retrodifferentiated HCC stem cells. Spheroid cultures of human HepaRG progenitors (HepaRG-Spheres), HBG-BC2, HepG2, and HuH7 cells and isolation of side population (SP) from HepaRG cells (HepaRG-SP) were analyzed by transcriptomics, signaling pathway analysis, and evaluation of chemotherapies. Gene expression profiling of HepaRG-SP and HepaRG-Spheres revealed enriched signatures related to cancer stem cells, metastasis, and recurrence and showed that HepaRG progenitors could retrodifferentiate into an immature state. The transcriptome from these stem cells matched that of proliferative bad outcome HCCs in a cohort of 457 patients. These HCC stem cells expressed high levels of cytokines triggering retrodifferentiation and displayed high migration and invasion potential. They also showed changes in mitochondrial activity with reduced membrane potential, low ATP production, and high lactate production. These changes were, in part, related to angiopoietin-like 4 (ANGPTL4)–induced upregulation of pyruvate dehydrogenase kinase 4 (PDK4), an inhibitor of mitochondrial pyruvate dehydrogenase. Upregulation of ANGPTL4 and PDK4 paralleled that of stem cells markers in human HCC specimens. Moreover, the PDK4 inhibitor dichloroacetate reversed chemoresistance to sorafenib or cisplatin in HCC stem cells derived from four HCC cell lines. In conclusion, retrodifferentiated cancer cells develop enhanced invasion and therapeutic resistance through ANGPTL4 and PDK4. Therefore, restoration of mitochondrial activity in combination with chemotherapy represents an attractive therapeutic approach in HCC.
Significance:
Restoring mitochondrial function in human hepatocellular carcinomas overcomes cancer resistance.
Data from Suppression of LIM Kinase 1 and LIM Kinase 2 Limits Glioblastoma Invasion
Authors: Chen Joseph , Ananthanarayanan Badriprasad , Springer Kelsey S. , Wolf Kayla J. , Sheyman Sharon M. , Tran Vivien D. , Kumar Sanjay
Published: March 2024

Abstract
The aggressive brain tumor glioblastoma (GBM) is characterized by rapid cellular infiltration of brain tissue, raising the possibility that disease progression could potentially be slowed by disrupting the machinery of cell migration. The LIM kinase isoforms LIMK1 and LIMK2 (LIMK1/2) play important roles in cell polarization, migration, and invasion and are markedly upregulated in GBM and many other infiltrative cancers. Yet, it remains unclear whether LIMK suppression could serve as a viable basis for combating GBM infiltration. In this study, we investigated effects of LIMK1/2 suppression on GBM invasion by combining GBM culture models, engineered invasion paradigms, and mouse xenograft models. While knockdown of either LIMK1 or LIMK2 only minimally influenced invasion in culture, simultaneous knockdown of both isoforms strongly reduced the invasive motility of continuous culture models and human GBM tumor-initiating cells (TIC) in both Boyden chamber and 3D hyaluronic acid spheroid invasion assays. Furthermore, LIMK1/2 functionally regulated cell invasiveness, in part, by disrupting polarized cell motility under confinement and cell chemotaxis. In an orthotopic xenograft model, TICs stably transduced with LIMK1/2 shRNA were implanted intracranially in immunocompromised mice. Tumors derived from LIMK1/2 knockdown TICs were substantially smaller and showed delayed growth kinetics and more distinct margins than tumors derived from control TICs. Overall, LIMK1/2 suppression increased mean survival time by 30%. These findings indicate that LIMK1/2 strongly regulate GBM invasive motility and tumor progression and support further exploration of LIMK1/2 as druggable targets.
Significance:
Targeting the actin-binding proteins LIMK1 and LIMK2 significantly diminishes glioblastoma invasion and spread, suggesting the potential value of these proteins as therapeutic targets.
Data from CD38-Driven Mitochondrial Trafficking Promotes Bioenergetic Plasticity in Multiple Myeloma
Authors: Marlein Christopher R. , Piddock Rachel E. , Mistry Jayna J. , Zaitseva Lyubov , Hellmich Charlotte , Horton Rebecca H. , Zhou Zhigang , Auger Martin J. , Bowles Kristian M. , Rushworth Stuart A.
Published: March 2024

Abstract
Metabolic adjustments are necessary for the initiation, proliferation, and spread of cancer cells. Although mitochondria have been shown to move to cancer cells from their microenvironment, the metabolic consequences of this phenomenon have yet to be fully elucidated. Here, we report that multiple myeloma cells use mitochondrial-based metabolism as well as glycolysis when located within the bone marrow microenvironment. The reliance of multiple myeloma cells on oxidative phosphorylation was caused by intercellular mitochondrial transfer to multiple myeloma cells from neighboring nonmalignant bone marrow stromal cells. This mitochondrial transfer occurred through tumor-derived tunneling nanotubes (TNT). Moreover, shRNA-mediated knockdown of CD38 inhibits mitochondrial transfer and TNT formation in vitro and blocks mitochondrial transfer and improves animal survival in vivo. This study describes a potential treatment strategy to inhibit mitochondrial transfer for clinical benefit and scientifically expands the understanding of the functional effects of mitochondrial transfer on tumor metabolism.
Significance:
Multiple myeloma relies on both oxidative phosphorylation and glycolysis following acquisition of mitochondria from its bone marrow microenvironment.

See related commentary by Boise and Shanmugam, p. 2102
Data from Epigenetic Regulation of the PTEN–AKT–RAC1 Axis by G9a Is Critical for Tumor Growth in Alveolar Rhabdomyosarcoma
Authors: Bhat Akshay V. , Palanichamy Kala Monica , Rao Vinay Kumar , Pignata Luca , Lim Huey Jin , Suriyamurthy Sudha , Chang Kenneth T. , Lee Victor K. , Guccione Ernesto , Taneja Reshma
Published: March 2024

Abstract
Alveolar rhabdomyosarcoma (ARMS) is an aggressive pediatric cancer with poor prognosis. As transient and stable modifications to chromatin have emerged as critical mechanisms in oncogenic signaling, efforts to target epigenetic modifiers as a therapeutic strategy have accelerated in recent years. To identify chromatin modifiers that sustain tumor growth, we performed an epigenetic screen and found that inhibition of lysine methyltransferase G9a significantly affected the viability of ARMS cell lines. Targeting expression or activity of G9a reduced cellular proliferation and motility in vitro and tumor growth in vivo. Transcriptome and chromatin immunoprecipitation–sequencing analysis provided mechanistic evidence that the tumor-suppressor PTEN was a direct target gene of G9a. G9a repressed PTEN expression in a methyltransferase activity–dependent manner, resulting in increased AKT and RAC1 activity. Re-expression of constitutively active RAC1 in G9a-deficient tumor cells restored oncogenic phenotypes, demonstrating its critical functions downstream of G9a. Collectively, our study provides evidence for a G9a-dependent epigenetic program that regulates tumor growth and suggests targeting G9a as a therapeutic strategy in ARMS.
Significance:
These findings demonstrate that RAC1 is an effector of G9a oncogenic functions and highlight the potential of G9a inhibitors in the treatment of ARMS.
Data from Smarcal1 and Zranb3 Protect Replication Forks from Myc-Induced DNA Replication Stress
Authors: Puccetti Matthew V. , Adams Clare M. , Kushinsky Saul , Eischen Christine M.
Published: March 2024

Abstract
The cellular DNA replication stress response functions to stabilize DNA replication forks and inhibits genome instability and tumorigenesis induced by oncogenes. However, the specific proteins required for resolving oncogenic stress remain poorly understood. Here we report that Smarcal1 and Zranb3, closely related replication fork–remodeling proteins, have nonredundant functions in resolving Myc-induced DNA replication stress. In Myc-overexpressing primary cells, significant differences in replication fork stalling, collapse, and DNA damage were detected between cells deficient in Smarcal1 or Zranb3, leading to changes in proliferation and apoptosis. These differences were also reflected in Myc-induced lymphoma development; haploinsufficiency of Smarcal1 resulted in accelerated lymphomagenesis, whereas haploinsufficiency of Zranb3 inhibited lymphoma development. Complete loss of either protein resulted in disparate survival outcomes. Our results reveal that endogenous replication stress from Myc in primary cells requires both alleles of Smarcal1 and Zranb3 and demonstrate the requirement of both proteins to stabilize replication forks upon Myc dysregulation in a nonredundant manner.
Significance:
Smarcal1 and Zranb3 are essential, but nonredundant, for responding to DNA replication stress and stabilizing replication forks following Myc overexpression.

See related commentary by Sotiriou and Halazonetis, p. 1297
Data from CoA Synthase (COASY) Mediates Radiation Resistance via PI3K Signaling in Rectal Cancer
Authors: Ferrandon Sylvain , DeVecchio Jennifer , Duraes Leonardo , Chouhan Hanumant , Karagkounis Georgios , Davenport Jacqueline , Orloff Matthew , Liska David , Kalady Matthew F.
Published: March 2024

Abstract
Neoadjuvant radiation is standard of care for locally advanced rectal cancer. Response to radiation is highly variable and directly linked with survival. However, there currently are no validated biomarkers or molecular targets to predict or improve radiation response, which would help develop personalized treatment and ideally targeted therapies. Here, we identified a novel biomarker, coenzyme A synthase (COASY), whose mRNA expression was consistently elevated in radioresistant human rectal cancers. This observation was validated in independent patient cohorts and further confirmed in colorectal cancer cell lines. Importantly, genetic overexpression and knockdown yielded radioresistant and sensitive phenotypes, respectively, in vitro and in vivo. COASY-knockdown xenografts were more vulnerable to radiation, showing delayed tumor growth, decreased proliferation, and increased apoptosis. Mechanistically, COASY protein directly interacted with the PI3K regulatory subunit PI3K-P85α, which increased AKT and mTOR phosphorylation, enhancing cell survival. Furthermore, shRNA COASY knockdown disrupted downstream PI3K pathway activation and also hindered DNA double-strand break repair, which both led to improved radiosensitivity. Collectively, this work reveals for the first time the biological relevance of COASY as a predictive rectal cancer biomarker for radiation response and offers mechanistic evidence to support COASY as a potential therapeutic target.
Significance:
COASY is a novel radiotherapy response modulator in rectal cancer that regulates PI3K activation and DNA repair. Furthermore, COASY levels directly correlate with radiation response and serve as a predictive biomarker.