bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Histone Methyltransferase SETDB1: A Common Denominator of Tumorigenesis with Therapeutic Potential
Authors: Strepkos Dimitrios , Markouli Mariam , Klonou Alexia , Papavassiliou Athanasios G. , Piperi Christina
Published: March 2023

Abstract
Epigenetic regulation of gene expression has been ultimately linked to cancer development, with posttranslational histone modifications representing attractive targets for disease monitoring and therapy. Emerging data have demonstrated histone lysine (K) methylation by methyltransferase SETDB1 as a common denominator of gene regulation in several cancer types. SETDB1 reversibly catalyzes the di- and trimethylation of histone 3 (H3) K9 in euchromatic regions of chromosomes, inhibiting gene transcription within these regions and promoting a switch from euchromatic to heterochromatic states. Recent studies have implicated aberrant SETDB1 activity in the development of various types of cancers, including brain, head and neck, lung, breast, gastrointestinal, ovarian, endometrial and prostate cancer, mesothelioma, melanoma, leukemias, and osteosarcoma. Although its role has not been fully elucidated in every case, most data point toward a pro-oncogenic potential of SETDB1 via the downregulation of critical tumor-suppressive genes. Less commonly, however, SETDB1 can also acquire a tumor-suppressive role, depending on cancer type and stage. Here we provide an updated overview of the cellular and molecular effects underlying SETDB1 activity in cancer development and progression along with current targeting strategies in different cancer types, with promising effects either as a standalone therapy or in conjunction with other therapeutic agents.
Data from EZH2-Targeted Therapies in Cancer: Hype or a Reality
Authors: Eich Marie-Lisa , Athar Mohammad , Ferguson James E. , Varambally Sooryanarayana
Published: March 2023

Abstract
Next-generation genomic sequencing has identified multiple novel molecular alterations in cancer. Since the identification of DNA methylation and histone modification, it has become evident that genes encoding epigenetic modifiers that locally and globally regulate gene expression play a crucial role in normal development and cancer progression. The histone methyltransferase enhancer of zeste homolog 2 (EZH2) is the enzymatic catalytic subunit of the polycomb-repressive complex 2 (PRC2) that can alter gene expression by trimethylating lysine 27 on histone 3 (H3K27). EZH2 is involved in global transcriptional repression, mainly targeting tumor-suppressor genes. EZH2 is commonly overexpressed in cancer and shows activating mutations in subtypes of lymphoma. Extensive studies have uncovered an important role for EZH2 in cancer progression and have suggested that it may be a useful therapeutic target. In addition, tumors harboring mutations in other epigenetic genes such as ARID1A, KDM6, and BAP1 are highly sensitive to EZH2 inhibition, thus increasing its potential as a therapeutic target. Recent studies also suggest that inhibition of EZH2 enhances the response to tumor immunotherapy. Many small-molecule inhibitors have been developed to target EZH2 or the PRC2 complex, with some of these inhibitors now in early clinical trials reporting clinical responses with acceptable tolerability. In this review, we highlight the recent advances in targeting EZH2, its successes, and potential limitations, and we discuss the future directions of this therapeutic subclass.
Data from Functional Determinants of Cell Cycle Plasticity and Sensitivity to CDK4/6 Inhibition
Authors: Kumarasamy Vishnu , Vail Paris , Nambiar Ram , Witkiewicz Agnieszka K. , Knudsen Erik S.
Published: March 2023

Abstract
Intrinsic or acquired resistance to clinically approved CDK4/6 inhibitors has emerged as a major obstacle that hinders their utility beyond ER+ breast cancer. In this study, CDK4/6-dependent and -resistant models were employed to identify functional determinants of response to pharmacologic CDK4/6 inhibitors. In all models tested, the activation of RB and inhibition of CDK2 activity emerged as determinants of sensitivity. While depleting CDK4 and 6 was sufficient to limit proliferation in specific resistance settings, RB loss rendered cells completely independent of these kinases. The main downstream target in this context was the activation status of CDK2, which was suppressed with CDK4/6 inhibition in an RB-dependent fashion. Protein levels of p27 were associated with plasticity/rigidity of the cell cycle and correlated with sensitivity to CDK4/6 inhibition. Exogenous overexpression and pharmacologic induction of p27 via inhibition of SKP2 and targeting the MEK/ERK pathway enhanced the cytostatic effect of CDK4/6 inhibitors. Mice bearing ER+ xenografts displayed a durable antitumor response to palbociclib; however, over the course of treatment, few cells retained RB phosphorylation, which was associated with limited p27 protein levels as determined by multispectral imaging. Similarly, combination treatment of palbociclib with a MEK inhibitor in pancreatic cancer PDX models upregulated p27 and further enhanced the in vivo tumor response to palbociclib. Collectively, these results suggest that the cell cycle plasticity, which enables tumor models to evade palbociclib-mediated activation of RB, could be targeted using a clinically applicable CDK2 inhibitor.
Significance:
This work provides a mechanistic insight toward understanding the functional roles of multiple cell cycle regulators that drive plasticity and sensitivity to CDK4/6 inhibition.
Data from MYC-Activated LncRNA MNX1-AS1 Promotes the Progression of Colorectal Cancer by Stabilizing YB1
Authors: Wu Qi-Nian , Luo Xiao-Jing , Liu Jia , Lu Yun-Xin , Wang Yun , Qi Jingjing , Liu Ze-Xian , Huang Qi-Tao , Liu Ze-Kun , Lu Jia-Bin , Jin Ying , Pu Heng-Ying , Hu Pei-Shan , Zheng Jia-Bo , Zeng Zhao-Lei , Ju Huai-Qiang , Xie Dan , Zhao Qi , Xu Ruihua
Published: March 2023

Abstract
Long noncoding RNAs (lncRNA) are involved in tumorigenesis and drug resistance. However, the roles and underlying mechanisms of lncRNAs in colorectal cancer are still unknown. In this work, through transcriptomic profiling analysis of 21 paired tumor and normal samples, we identified a novel colorectal cancer–related lncRNA, MNX1-AS1. MNX1-AS1 expression was significantly upregulated in colorectal cancer and associated with poor prognosis. In vitro and in vivo gain- and loss-of-function experiments showed that MNX1-AS1 promotes the proliferation of colorectal cancer cells. MNX1-AS1 bound to and activated Y-box-binding protein 1 (YB1), a multifunctional RNA/DNA-binding protein, and prevented its ubiquitination and degradation. A marked overlap between genes that are differentially expressed in MNX1-AS1 knockdown cells and transcriptional targets of YB1 was observed. YB1 knockdown mimicked the loss of viability phenotype observed upon depletion of MNX1-AS1. In addition, MYC bound the promoter of the MNX1-AS1 locus and activated its transcription. In vivo experiments showed that ASO inhibited MNX1-AS1, which suppressed the proliferation of colorectal cancer cells in both cell-based and patient-derived xenograft models. Collectively, these findings suggest that the MYC–MNX1-AS1–YB1 axis might serve as a potential biomarker and therapeutic target in colorectal cancer.
Significance:
This study highlights the discovery of a novel colorectal cancer biomarker and therapeutic target, MNX1-AS1, a long noncoding RNA that drives proliferation via a MYC/MNX1-AS1/YB1 signaling pathway.
Data from KIF15-Mediated Stabilization of AR and AR-V7 Contributes to Enzalutamide Resistance in Prostate Cancer
Authors: Gao Lin , Zhang Wenbo , Zhang Jing , Liu Junmei , Sun Feifei , Liu Hui , Hu Jing , Wang Xin , Wang Xueli , Su Peng , Chen Shouzhen , Qu Sifeng , Shi Benkang , Xiong Xueting , Chen Weiwen , Dong Xuesen , Han Bo
Published: March 2023

Abstract
The new generation androgen receptor (AR) pathway inhibitor enzalutamide can prolong the survival of patients with metastatic prostate cancer. However, resistance to enzalutamide inevitably develops in these patients, and the underlying mechanisms of this resistance are not fully defined. Here we demonstrate that the kinesin family member 15 (KIF15) contributes to enzalutamide resistance by enhancing the AR signaling in prostate cancer cells. KIF15 directly bound the N-terminus of AR/AR-V7 and prevented AR/AR-V7 proteins from degradation by increasing the protein association of ubiquitin-specific protease 14 (USP14) with AR/AR-V7. In turn, the transcriptionally active AR stimulated KIF15 expression. KIF15 inhibitors alone or in combination with enzalutamide significantly suppressed enzalutamide-resistant prostate cancer cell growth and xenograft progression. These findings highlight a key role of KIF15 in enabling prostate cancer cells to develop therapy resistance to enzalutamide and rationalize KIF15 as a potential therapeutic target.
Significance:
These findings demonstrate how reciprocal activation between KIF15 and AR contributes to enzalutamide resistance in prostate cancer and highlights cotargeting KIF15 and AR as a therapeutic strategy for these tumors.
Data from PLK1 Induces Chromosomal Instability and Overrides Cell-Cycle Checkpoints to Drive Tumorigenesis
Authors: Gheghiani Lilia , Wang Lei , Zhang Youwei , Moore Xavier T.R. , Zhang Jinglei , Smith Steven C. , Tian Yijun , Wang Liang , Turner Kristi , Jackson-Cook Colleen K. , Mukhopadhyay Nitai D. , Fu Zheng
Published: March 2023

Abstract
Polo-like kinase 1 (PLK1) is an essential cell-cycle regulator that is frequently overexpressed in various human cancers. To determine whether Plk1 overexpression drives tumorigenesis, we established transgenic mouse lines that ubiquitously express increased levels of Plk1. High Plk1 levels were a driving force for different types of spontaneous tumors. Increased Plk1 levels resulted in multiple defects in mitosis and cytokinesis, supernumerary centrosomes, and compromised cell-cycle checkpoints, allowing accumulation of chromosomal instability (CIN), which resulted in aneuploidy and tumor formation. Clinically, higher expression of PLK1 positively associated with an increase in genome-wide copy-number alterations in multiple human cancers. This study provides in vivo evidence that aberrant expression of PLK1 triggers CIN and tumorigenesis and highlights potential therapeutic opportunities for CIN-positive cancers.
Significance:
These findings establish roles for PLK1 as a potent proto-oncogene and a CIN gene and provide insights for the development of effective treatment regimens across PLK1-overexpressing and CIN-positive cancers.
Data from 14-3-3σ Functions as an Intestinal Tumor Suppressor
Authors: Winter Markus , Rokavec Matjaž , Hermeking Heiko
Published: March 2023

Abstract
Although the 14-3-3σ gene was initially identified as a p53 target gene in colorectal cancer cells, its potential role in intestinal tumorigenesis has remained unknown. Here we determined that 14-3-3σ expression is significantly downregulated in primary human colorectal cancer when compared with adjacent normal colonic tissue in patient samples. Downregulation of 14-3-3σ in primary colorectal cancers was significantly associated with p53 mutation, increasing tumor stage, distant metastasis, and poor patient survival. Poor survival was more significantly associated with decreased 14-3-3σ expression in p53 wild-type than in p53-mutant colorectal cancers. 14-3-3σ expression was detected in enterocytes of the transit amplifying zone and gradually increased towards the apical villi in the small intestinal epithelium. In small and large intestinal epithelia and adenomas, 14-3-3σ expression was upregulated in differentiated areas. Deletion of 14-3-3σ in ApcMin mice increased the number and size of adenomas in the small intestine and colon, shortening the median survival by 64 days. 14-3-3σ–deficient adenomas displayed increased proliferation and decreased apoptosis, as well as increased dysplasia. In adenomas, loss of 14-3-3σ promoted acquisition of a mesenchymal-like gene expression signature, which was also found in colorectal cancers from patients with poor relapse-free survival. The transcriptional programs controlled by the 14-3-3σ-interacting factors SNAIL, c-JUN, YAP1, and FOXO1 were activated by deletion of 14-3-3σ, potentially contributing to the enhanced tumor formation and growth. Taken together, these results provide genetic evidence of a tumor-suppressor function of 14-3-3σ in the intestine.
Significance:
Downregulation of 14-3-3σ in colorectal cancer is associated with metastasis and poor survival of patients, and its inactivation in a murine tumor model drives intestinal tumor formation and epithelial-mesenchymal transition.
Data from Pharmacological Disruption of the Notch1 Transcriptional Complex Inhibits Tumor Growth by Selectively Targeting Cancer Stem Cells
Authors: Alvarez-Trotta Annamil , Guerrant William , Astudillo Luisana , Lahiry Mohini , Diluvio Giulia , Shersher Elena , Kaneku Hugo , Robbins David J. , Orton Darren , Capobianco Anthony J.
Published: March 2023

Abstract
In many human cancers, deregulation of the Notch pathway has been shown to play a role in the initiation and maintenance of the neoplastic phenotype. Aberrant Notch activity also plays a central role in the maintenance and survival of cancer stem cells (CSC), which underlie metastasis and resistance to therapy. For these reasons, inhibition of Notch signaling has become an exceedingly attractive target for cancer therapeutic development. However, attempts to develop Notch pathway–specific drugs have largely failed in the clinic, in part due to intestinal toxicity. Here, we report the discovery of NADI-351, the first specific small-molecule inhibitor of Notch1 transcriptional complexes. NADI-351 selectively disrupted Notch1 transcription complexes and reduced Notch1 recruitment to target genes. NADI-351 demonstrated robust antitumor activity without inducing intestinal toxicity in mouse models, and CSCs were ablated by NADI-351 treatment. Our study demonstrates that NADI-351 is an orally available and potent inhibitor of Notch1-mediated transcription that inhibits tumor growth with low toxicity, providing a potential therapeutic approach for improved cancer treatment.
Significance:
This study showcases the first Notch1-selective inhibitor that suppresses tumor growth with limited toxicity by selectively ablating cancer stem cells.
Data from ENO1 Promotes Lung Cancer Metastasis via HGFR and WNT Signaling–Driven Epithelial-to-Mesenchymal Transition
Authors: Li Hsin-Jung , Ke Feng-Yi , Lin Chia-Ching , Lu Mei-Yi , Kuo Yi-Huei , Wang Yi-Ping , Liang Kang-Hao , Lin Shin-Chang , Chang Ya-Hsuan , Chen Hsuan-Yu , Yang Pan-Chyr , Wu Han-Chung
Published: March 2023

Abstract
ENO1 (α-enolase) expression is significantly correlated with reduced survival and poor prognosis in many cancer types, including lung cancer. However, the function of ENO1 in carcinogenesis remains elusive. In this study, we found that high expression of ENO1 is present in metastatic lung cancer cell lines and malignant tumors and is associated with poor overall survival of patients with lung cancer. Knockdown of ENO1 decreased cancer cell proliferation and invasiveness, whereas overexpression of ENO1 enhanced these processes. Moreover, ENO1 expression promoted tumor growth in orthotopic models and enhanced lung tumor metastasis in tail-vein injection models. These effects were mediated by upregulation of mesenchymal markers N-cadherin and vimentin and the epithelial-to-mesenchymal transition regulator SLUG, along with concurrent downregulation of E-cadherin. Mechanistically, ENO1 interacted with hepatocyte growth factor receptor (HGFR) and activated HGFR and Wnt signaling via increased phosphorylation of HGFR and the Wnt coreceptor LRP5/6. Activation of these signaling axes decreased GSK3β activity via Src–PI3K–AKT signaling and inactivation of the β-catenin destruction complex to ultimately upregulate SLUG and β-catenin. In addition, we generated a chimeric anti-ENO1 mAb (chENO1-22) that can decrease cancer cell proliferation and invasion. chENO1-22 attenuated cancer cell invasion by inhibiting ENO1-mediated GSK3β inactivation to promote SLUG protein ubiquitination and degradation. Moreover, chENO1-22 prevented lung tumor metastasis and prolonged survival in animal models. Taken together, these findings illuminate the molecular mechanisms underlying the function of ENO1 in lung cancer metastasis and support the therapeutic potential of a novel antibody targeting ENO1 for treating lung cancer.
Significance:
This study shows that ENO1 promotes lung cancer metastasis via HGFR and WNT signaling and introduces a novel anti-ENO1 antibody for potential therapeutic use in lung cancer.
Data from The CD200–CD200R Axis Promotes Squamous Cell Carcinoma Metastasis via Regulation of Cathepsin K
Authors: Khan Iasha Z. , Del Guzzo Christina A. , Shao Anqi , Cho Jiyoon , Du Rong , Cohen Adrienne O. , Owens David M.
Published: March 2023

Abstract
The CD200–CD200R immunoregulatory signaling axis plays an etiologic role in the survival and spread of numerous cancers, primarily through suppression of antitumor immune surveillance. Our previous work outlined a prometastatic role for the CD200–CD200R axis in cutaneous squamous cell carcinoma (cSCC) that is independent of direct T-cell suppression but modulates the function of infiltrating myeloid cells. To identify effectors of the CD200–CD200R axis important for cSCC metastasis, we conducted RNA sequencing profiling of infiltrating CD11B+Cd200R+ cells isolated from CD200+ versus CD200-null cSCCs and identified the cysteine protease cathepsin K (Ctsk) to be highly upregulated in CD200+ cSCCs. CD11B+Cd200R+ cells expressed phenotypic markers associated with myeloid-derived suppressor cell–like cells and tumor-associated macrophages and were the primary source of Ctsk expression in cSCC. A Cd200R+ myeloid cell–cSCC coculture system showed that induction of Ctsk was dependent on engagement of the CD200–CD200R axis, indicating that Ctsk is a target gene of this pathway in the cSCC tumor microenvironment. Inhibition of Ctsk, but not matrix metalloproteinases, significantly blocked cSCC cell migration in vitro. Finally, targeted CD200 disruption in tumor cells and Ctsk pharmacologic inhibition significantly reduced cSCC metastasis in vivo. Collectively, these findings support the conclusion that CD200 stimulates cSCC invasion and metastasis via induction of Ctsk in CD200R+ infiltrating myeloid cells.
Significance:
These findings highlight the relationship between CD200–CD200R and cathepsin K in cutaneous squamous cell carcinoma metastasis and suggest that either of these components may serve as a viable therapeutic target in this disease.
Data from Dual Covalent Inhibition of PKM and IMPDH Targets Metabolism in Cutaneous Metastatic Melanoma
Authors: Zerhouni Marwa , Martin Anthony R. , Furstoss Nathan , Gutierrez Vincent S. , Jaune Emilie , Tekaya Nedra , Beranger Guillaume E. , Abbe Patricia , Regazzetti Claire , Amdouni Hella , Driowya Mohsine , Dubreuil Patrice , Luciano Frédéric , Jacquel Arnaud , Tulic Meri K. , Cluzeau Thomas , O'Hara Brendan P. , Ben-Sahra Issam , Passeron Thierry , Benhida Rachid , Robert Guillaume , Auberger Patrick , Rocchi Stéphane
Published: March 2023

Abstract
Overcoming acquired drug resistance is a primary challenge in cancer treatment. Notably, more than 50% of patients with BRAFV600E cutaneous metastatic melanoma (CMM) eventually develop resistance to BRAF inhibitors. Resistant cells undergo metabolic reprogramming that profoundly influences therapeutic response and promotes tumor progression. Uncovering metabolic vulnerabilities could help suppress CMM tumor growth and overcome drug resistance. Here we identified a drug, HA344, that concomitantly targets two distinct metabolic hubs in cancer cells. HA344 inhibited the final and rate-limiting step of glycolysis through its covalent binding to the pyruvate kinase M2 (PKM2) enzyme, and it concurrently blocked the activity of inosine monophosphate dehydrogenase, the rate-limiting enzyme of de novo guanylate synthesis. As a consequence, HA344 efficiently targeted vemurafenib-sensitive and vemurafenib-resistant CMM cells and impaired CMM xenograft tumor growth in mice. In addition, HA344 acted synergistically with BRAF inhibitors on CMM cell lines in vitro. Thus, the mechanism of action of HA344 provides potential therapeutic avenues for patients with CMM and a broad range of different cancers.
Significance:
Glycolytic and purine synthesis pathways are often deregulated in therapy-resistant tumors and can be targeted by the covalent inhibitor described in this study, suggesting its broad application for overcoming resistance in cancer.
Data from Altering the Microbiome Inhibits Tumorigenesis in a Mouse Model of Oviductal High-Grade Serous Carcinoma
Authors: Chen Lixing , Zhai Yali , Wang Yisheng , Fearon Eric R. , Núñez Gabriel , Inohara Naohiro , Cho Kathleen R.
Published: March 2023

Abstract
Studies have shown bacteria influence the initiation and progression of cancers arising in sites that harbor rich microbial communities, such as the colon. Little is known about the potential for the microbiome to influence tumorigenesis at sites considered sterile, including the upper female genital tract. The recent identification of distinct bacterial signatures associated with ovarian carcinomas suggests microbiota in the gut, vagina, or elsewhere might contribute to ovarian cancer pathogenesis. Here, we tested whether altering the microbiome affects tumorigenesis in a mouse model of high-grade serous carcinoma (HGSC) based on conditional oviduct-specific inactivation of the Brca1, Trp53, Rb1, and Nf1 tumor suppressor genes. Cohorts of control (n = 20) and antibiotic-treated (n = 23) mice were treated with tamoxifen to induce tumor formation and then monitored for 12 months. The antibiotic cocktail was administered for the first 5 months of the monitoring period in the treatment group. Antibiotic-treated mice had significantly fewer and less advanced tumors than control mice at study endpoint. Antibiotics induced changes in the composition of the intestinal and vaginal microbiota, which were durable in the fecal samples. Clustering analysis showed particular groups of microbiota are associated with the development of HGSC in this model. These findings demonstrate the microbiome influences HGSC pathogenesis in an in vivo model that closely recapitulates the human disease. Because the microbiome can modulate efficacy of cancer chemo- and immunotherapy, our genetically engineered mouse model system may prove useful for testing whether altering the microbiota can improve the heretofore poor response of HGSC to immunotherapies.
Significance:
This study provides strong in vivo evidence for a role of the microbiome in ovarian cancer pathogenesis.
Data from Nonsense-Mediated RNA Decay Is a Unique Vulnerability of Cancer Cells Harboring SF3B1 or U2AF1 Mutations
Authors: Cheruiyot Abigael , Li Shan , Nonavinkere Srivatsan Sridhar , Ahmed Tanzir , Chen Yuhao , Lemacon Delphine S. , Li Ying , Yang Zheng , Wadugu Brian A. , Warner Wayne A. , Pruett-Miller Shondra M. , Obeng Esther A. , Link Daniel C. , He Dalin , Xiao Fei , Wang Xiaowei , Bailis Julie M. , Walter Matthew J. , You Zhongsheng
Published: March 2023

Abstract
Nonsense-mediated RNA decay (NMD) is recognized as an RNA surveillance pathway that targets aberrant mRNAs with premature translation termination codons (PTC) for degradation, however, its molecular mechanisms and roles in health and disease remain incompletely understood. In this study, we developed a novel reporter system to accurately measure NMD activity in individual cells. A genome-wide CRISPR-Cas9 knockout screen using this reporter system identified novel NMD-promoting factors, including multiple components of the SF3B complex and other U2 spliceosome factors. Interestingly, cells with mutations in the spliceosome genes SF3B1 and U2AF1, which are commonly found in myelodysplastic syndrome (MDS) and cancers, have overall attenuated NMD activity. Compared with wild-type (WT) cells, SF3B1- and U2AF1-mutant cells were more sensitive to NMD inhibition, a phenotype that is accompanied by elevated DNA replication obstruction, DNA damage, and chromosomal instability. Remarkably, the sensitivity of spliceosome mutant cells to NMD inhibition was rescued by overexpression of RNase H1, which removes R-loops in the genome. Together, these findings shed new light on the functional interplay between NMD and RNA splicing and suggest a novel synthetic lethal strategy for the treatment of MDS and cancers with spliceosome mutations.
Significance:
This study has developed a novel NMD reporter system and identified a potential therapeutic approach of targeting the NMD pathway to treat cancer with spliceosome gene mutations.
Data from Oncogenic Ras Disrupts Epithelial Integrity by Activating the Transmembrane Serine Protease Hepsin
Authors: Tervonen Topi A. , Pant Shishir M. , Belitškin Denis , Englund Johanna I. , Närhi Katja , Haglund Caj , Kovanen Panu E. , Verschuren Emmy W. , Klefström Juha
Published: March 2023

Abstract
Ras proteins play a causal role in human cancer by activating multiple pathways that promote cancer growth and invasion. However, little is known about how Ras induces the first diagnostic features of invasion in solid tumors, including loss of epithelial integrity and breaching of the basement membrane (BM). In this study, we found that oncogenic Ras strongly promotes the activation of hepsin, a member of the hepsin/TMPRSS type II transmembrane serine protease family. Mechanistically, the Ras-dependent hepsin activation was mediated via Raf–MEK–ERK signaling, which controlled hepsin protein stability through the heat shock transcription factor-1 stress pathway. In Ras-transformed three-dimensional mammary epithelial culture, ablation of hepsin restored desmosomal cell–cell junctions, hemidesmosomes, and BM integrity and epithelial cohesion. In tumor xenografts harboring mutant KRas, silencing of hepsin increased local invasion concomitantly with accumulation of collagen IV. These findings suggest that hepsin is a critical protease for Ras-dependent tumorigenesis, executing cell–cell and cell–matrix pathologies important for early tumor dissemination.
Significance:
These findings identify the cell-surface serine protease hepsin as a potential therapeutic target for its role in oncogenic Ras-mediated deregulation of epithelial cell–cell and cell–matrix interactions and cohesion of epithelial structure.
Data from STK11/LKB1 Loss of Function Is Associated with Global DNA Hypomethylation and S-Adenosyl-Methionine Depletion in Human Lung Adenocarcinoma
Authors: Koenig Michael J. , Agana Bernice A. , Kaufman Jacob M. , Sharpnack Michael F. , Wang Walter Z. , Weigel Christoph , Navarro Fabio C.P. , Amann Joseph M. , Cacciato Nicole , Arasada Rajeswara Rao , Gerstein Mark B. , Wysocki Vicki H. , Oakes Christopher , Carbone David P.
Published: March 2023

Abstract
STK11 (liver kinase B1, LKB1) is the fourth most frequently mutated gene in lung adenocarcinoma, with loss of function observed in up to 30% of all cases. Our previous work identified a 16-gene signature for LKB1 loss of function through mutational and nonmutational mechanisms. In this study, we applied this genetic signature to The Cancer Genome Atlas (TCGA) lung adenocarcinoma samples and discovered a novel association between LKB1 loss and widespread DNA demethylation. LKB1-deficient tumors showed depletion of S-adenosyl-methionine (SAM-e), which is the primary substrate for DNMT1 activity. Lower methylation following LKB1 loss involved repetitive elements (RE) and altered RE transcription, as well as decreased sensitivity to azacytidine. Demethylated CpGs were enriched for FOXA family consensus binding sites, and nuclear expression, localization, and turnover of FOXA was dependent upon LKB1. Overall, these findings demonstrate that a large number of lung adenocarcinomas exhibit global hypomethylation driven by LKB1 loss, which has implications for both epigenetic therapy and immunotherapy in these cancers.
Significance:
Lung adenocarcinomas with LKB1 loss demonstrate global genomic hypomethylation associated with depletion of SAM-e, reduced expression of DNMT1, and increased transcription of repetitive elements.
Data from Nicotinamide Mononucleotide Prevents Cisplatin-Induced Cognitive Impairments
Authors: Yoo Ki Hyun , Tang Jason J. , Rashid Mohammad Abdur , Cho Chang Hoon , Corujo-Ramirez Ana , Choi Jonghoon , Bae Mun Gyeong , Brogren Danielle , Hawse John R. , Hou Xiaonan , Weroha S. John , Oliveros Alfredo , Kirkeby Lindsey A. , Baur Joseph A. , Jang Mi-Hyeon
Published: March 2023

Abstract
Chemotherapy-induced cognitive impairment (CICI) is often reported as a neurotoxic side effect of chemotherapy. Although CICI has emerged as a significant medical problem, meaningful treatments are not currently available due to a lack of mechanistic understanding underlying CICI pathophysiology. Using the platinum-based chemotherapy cisplatin as a model for CICI, we show here that cisplatin suppresses nicotinamide adenine dinucleotide (NAD+) levels in the adult female mouse brain in vivo and in human cortical neurons derived from induced pluripotent stem cells in vitro. Increasing NAD+ levels through nicotinamide mononucleotide (NMN) administration prevented cisplatin-induced abnormalities in neural progenitor proliferation, neuronal morphogenesis, and cognitive function without affecting tumor growth and antitumor efficacy of cisplatin. Mechanistically, cisplatin inhibited expression of the NAD+ biosynthesis rate-limiting enzyme nicotinamide phosphoribosyl transferase (Nampt). Selective restoration of Nampt expression in adult-born neurons was sufficient to prevent cisplatin-induced defects in dendrite morphogenesis and memory function. Taken together, our findings suggest that aberrant Nampt-mediated NAD+ metabolic pathways may be a key contributor in cisplatin-induced neurogenic impairments, thus causally leading to memory dysfunction. Therefore, increasing NAD+ levels could represent a promising and safe therapeutic strategy for cisplatin-related neurotoxicity.
Significance:
Increasing NAD+ through NMN supplementation offers a potential therapeutic strategy to safely prevent cisplatin-induced cognitive impairments, thus providing hope for improved quality of life in cancer survivors.
Data from Ferroptosis Inducers Are a Novel Therapeutic Approach for Advanced Prostate Cancer
Authors: Ghoochani Ali , Hsu En-Chi , Aslan Merve , Rice Meghan A. , Nguyen Holly M. , Brooks James D. , Corey Eva , Paulmurugan Ramasamy , Stoyanova Tanya
Published: March 2023

Abstract
Ferroptosis is a type of programmed cell death induced by the accumulation of lipid peroxidation and lipid reactive oxygen species in cells. It has been recently demonstrated that cancer cells are vulnerable to ferroptosis inducers (FIN). However, the therapeutic potential of FINs in prostate cancer in preclinical settings has not been explored. In this study, we demonstrate that mediators of ferroptosis, solute carrier family 7 member 11, SLC3A2, and glutathione peroxidase, are expressed in treatment-resistant prostate cancer. We further demonstrate that treatment-resistant prostate cancer cells are sensitive to two FINs, erastin and RSL3. Treatment with erastin and RSL3 led to a significant decrease in prostate cancer cell growth and migration in vitro and significantly delayed the tumor growth of treatment-resistant prostate cancer in vivo, with no measurable side effects. Combination of erastin or RSL3 with standard-of-care second-generation antiandrogens for advanced prostate cancer halted prostate cancer cell growth and migration in vitro and tumor growth in vivo. These results demonstrate the potential of erastin or RSL3 independently and in combination with standard-of-care second-generation antiandrogens as novel therapeutic strategies for advanced prostate cancer.
Significance:
These findings reveal that induction of ferroptosis is a new therapeutic strategy for advanced prostate cancer as a monotherapy and in combination with second-generation antiandrogens.
Data from Inhibition of Granulocytic Myeloid-Derived Suppressor Cells Overcomes Resistance to Immune Checkpoint Inhibition in LKB1-Deficient Non–Small Cell Lung Cancer
Authors: Li Rui , Salehi-Rad Ramin , Crosson William , Momcilovic Milica , Lim Raymond J. , Ong Stephanie L. , Huang Zi Ling , Zhang Tianhao , Abascal Jensen , Dumitras Camelia , Jing Zhe , Park Stacy J. , Krysan Kostyantyn , Shackelford David B. , Tran Linh M. , Liu Bin , Dubinett Steven M.
Published: March 2023

Abstract
LKB1 inactivating mutations are commonly observed in patients with KRAS-mutant non–small cell lung cancer (NSCLC). Although treatment of NSCLC with immune checkpoint inhibitors (ICI) has resulted in improved overall survival in a subset of patients, studies have revealed that co-occurring KRAS/LKB1 mutations drive primary resistance to ICIs in NSCLC. Effective therapeutic options that overcome ICI resistance in LKB1-mutant NSCLC are limited. Here, we report that loss of LKB1 results in increased secretion of the C–X–C motif (CXC) chemokines with an NH2-terminal Glu-Leu-Arg (ELR) motif in premalignant and cancerous cells, as well as in genetically engineered murine models (GEMM) of NSCLC. Heightened levels of ELR+ CXC chemokines in LKB1-deficient murine models of NSCLC positively correlated with increased abundance of granulocytic myeloid-derived suppressor cells (G-MDSC) locally within the tumor microenvironment and systemically in peripheral blood and spleen. Depletion of G-MDSCs with antibody or functional inhibition via all-trans-retinoic acid (ATRA) led to enhanced antitumor T-cell responses and sensitized LKB1-deficent murine tumors to PD-1 blockade. Combination therapy with anti–PD-1 and ATRA improved local and systemic T-cell proliferation and generated tumor-specific immunity. Our findings implicate ELR+ CXC chemokine-mediated enrichment of G-MDSCs as a potential mediator of immunosuppression in LKB1-deficient NSCLC and provide a rationale for using ATRA in combination with anti–PD-1 therapy in patients with LKB1-deficient NSCLC refractory to ICIs.
Significance:
These findings show that accumulation of myeloid-derived suppressor cells in LKB1-deficient non–small cell lung cancer can be overcome via treatment with all-trans-retinoic acid, sensitizing tumors to immunotherapy.
Data from Photoacoustic Tomography Detects Response and Resistance to Bevacizumab in Breast Cancer Mouse Models
Authors: Quiros-Gonzalez Isabel , Tomaszewski Michal R. , Golinska Monika A. , Brown Emma , Ansel-Bollepalli Laura , Hacker Lina , Couturier Dominique-Laurent , Sainz Rosa M. , Bohndiek Sarah E.
Published: March 2023

Abstract
Angiogenesis is an established prognostic factor in advanced breast cancer, yet response to antiangiogenic therapies in this disease remains highly variable. Noninvasive imaging biomarkers could help identify patients that will benefit from antiangiogenic therapy and provide an ideal tool for longitudinal monitoring, enabling dosing regimens to be altered with real-time feedback. Photoacoustic tomography (PAT) is an emerging imaging modality that provides a direct readout of tumor hemoglobin concentration and oxygenation. We hypothesized that PAT could be used in the longitudinal setting to provide an early indication of response or resistance to antiangiogenic therapy. To test this hypothesis, PAT was performed over time in estrogen receptor–positive and estrogen receptor–negative breast cancer xenograft mouse models undergoing treatment with the antiangiogenic bevacizumab as a single agent. The cohort of treated tumors, which were mostly resistant to the treatment, contained a subset that demonstrated a clear survival benefit. At endpoint, the PAT data from the responding subset showed significantly lower oxygenation and higher hemoglobin content compared with both resistant and control tumors. Longitudinal analysis revealed that tumor oxygenation diverged significantly in the responding subset, identifying early treatment response and the evolution of different vascular phenotypes between the subsets. Responding tumors were characterized by a more angiogenic phenotype when analyzed with IHC, displaying higher vessel density, yet poorer vascular maturity and elevated hypoxia. Taken together, our findings indicate that PAT shows promise in providing an early indication of response or resistance to antiangiogenic therapy.
Significance:
Photoacoustic assessment of tumor oxygenation is a noninvasive early indicator of response to bevacizumab therapy, clearly distinguishing between control, responding, and resistant tumors within just a few weeks of treatment.
Data from Aberrant Expression and Subcellular Localization of ECT2 Drives Colorectal Cancer Progression and Growth
Authors: Cook Danielle R. , Kang Melissa , Martin Timothy D. , Galanko Joseph A. , Loeza Gabriela H. , Trembath Dimitri G. , Justilien Verline , Pickering Karen A. , Vincent David F. , Jarosch Armin , Jurmeister Philipp , Waters Andrew M. , Hibshman Priya S. , Campbell Andrew D. , Ford Catriona A. , Keku Temitope O. , Yeh Jen Jen , Lee Michael S. , Cox Adrienne D. , Fields Alan P. , Sandler Robert S. , Sansom Owen J. , Sers Christine , Schaefer Antje , Der Channing J.
Published: March 2023

Abstract
ECT2 is an activator of RHO GTPases that is essential for cytokinesis. In addition, ECT2 was identified as an oncoprotein when expressed ectopically in NIH/3T3 fibroblasts. However, oncogenic activation of ECT2 resulted from N-terminal truncation, and such truncated ECT2 proteins have not been found in patients with cancer. In this study, we observed elevated expression of full-length ECT2 protein in preneoplastic colon adenomas, driven by increased ECT2 mRNA abundance and associated with APC tumor-suppressor loss. Elevated ECT2 levels were detected in the cytoplasm and nucleus of colorectal cancer tissue, suggesting cytoplasmic mislocalization as one mechanism of early oncogenic ECT2 activation. Importantly, elevated nuclear ECT2 correlated with poorly differentiated tumors, and a low cytoplasmic:nuclear ratio of ECT2 protein correlated with poor patient survival, suggesting that nuclear and cytoplasmic ECT2 play distinct roles in colorectal cancer. Depletion of ECT2 reduced anchorage-independent cancer cell growth and invasion independent of its function in cytokinesis, and loss of Ect2 extended survival in a KrasG12D Apc-null colon cancer mouse model. Expression of ECT2 variants with impaired nuclear localization or guanine nucleotide exchange catalytic activity failed to restore cancer cell growth or invasion, indicating that active, nuclear ECT2 is required to support tumor progression. Nuclear ECT2 promoted ribosomal DNA transcription and ribosome biogenesis in colorectal cancer. These results support a driver role for both cytoplasmic and nuclear ECT2 overexpression in colorectal cancer and emphasize the critical role of precise subcellular localization in dictating ECT2 function in neoplastic cells.
Significance:
ECT2 overexpression and mislocalization support its role as a driver in colon cancer that is independent from its function in normal cell cytokinesis.
Data from Targeting LRRC15 Inhibits Metastatic Dissemination of Ovarian Cancer
Authors: Ray Upasana , Jung Deok-Beom , Jin Ling , Xiao Yinan , Dasari Subramanyam , Sarkar Bhattacharya Sayantani , Thirusangu Prabhu , Staub Julie K. , Roy Debarshi , Roy Bhaskar , Weroha S. John , Hou Xiaonan , Purcell James W. , Bakkum-Gamez Jamie N. , Kaufmann Scott H. , Kannan Nagarajan , Mitra Anirban K. , Shridhar Viji
Published: March 2023

Abstract
Dissemination of ovarian cancer cells can lead to inoperable metastatic lesions in the bowel and omentum that cause patient death. Here we show that LRRC15, a type-I 15-leucine–rich repeat-containing membrane protein, highly overexpressed in ovarian cancer bowel metastases compared with matched primary tumors and acts as a potent promoter of omental metastasis. Complementary models of ovarian cancer demonstrated that LRRC15 expression leads to inhibition of anoikis-induced cell death and promotes adhesion and invasion through matrices that mimic omentum. Mechanistically, LRRC15 interacted with β1-integrin to stimulate activation of focal adhesion kinase (FAK) signaling. As a therapeutic proof of concept, targeting LRRC15 with the specific antibody–drug conjugate ABBV-085 in both early and late metastatic ovarian cancer cell line xenograft models prevented metastatic dissemination, and these results were corroborated in metastatic patient-derived ovarian cancer xenograft models. Furthermore, treatment of 3D-spheroid cultures of LRRC15-positive patient-derived ascites with ABBV-085 reduced cell viability. Overall, these data uncover a role for LRRC15 in promoting ovarian cancer metastasis and suggest a novel and promising therapy to target ovarian cancer metastases.

Significance: This study identifies that LRRC15 activates β1-integrin/FAK signaling to promote ovarian cancer metastasis and shows that the LRRC15-targeted antibody–drug conjugate ABBV-085 suppresses ovarian cancer metastasis in preclinical models.
Data from Phosphorylation of SHP2 at Tyr62 Enables Acquired Resistance to SHP2 Allosteric Inhibitors in FLT3-ITD–Driven AML
Authors: Pfeiffer Anamarija , Franciosa Giulia , Locard-Paulet Marie , Piga Ilaria , Reckzeh Kristian , Vemulapalli Vidyasiri , Blacklow Stephen C. , Theilgaard-Mönch Kim , Jensen Lars J. , Olsen Jesper V.
Published: March 2023

Abstract
The protein tyrosine phosphatase SHP2 is crucial for oncogenic transformation of acute myeloid leukemia (AML) cells expressing mutated receptor tyrosine kinases. SHP2 is required for full RAS-ERK activation to promote cell proliferation and survival programs. Allosteric SHP2 inhibitors act by stabilizing SHP2 in its autoinhibited conformation and are currently being tested in clinical trials for tumors with overactivation of the RAS/ERK pathway, alone and in various drug combinations. In this study, we established cells with acquired resistance to the allosteric SHP2 inhibitor SHP099 from two FLT3-ITD (internal tandem duplication)-positive AML cell lines. Label-free and isobaric labeling quantitative mass spectrometry–based phosphoproteomics of these resistant models demonstrated that AML cells can restore phosphorylated ERK (pERK) in the presence of SHP099, thus developing adaptive resistance. Mechanistically, SHP2 inhibition induced tyrosine phosphorylation and feedback-driven activation of the FLT3 receptor, which in turn phosphorylated SHP2 on tyrosine 62. This phosphorylation stabilized SHP2 in its open conformation, preventing SHP099 binding and conferring resistance. Combinatorial inhibition of SHP2 and MEK or FLT3 prevented pERK rebound and resistant cell growth. The same mechanism was observed in a FLT3-mutated B-cell acute lymphoblastic leukemia cell line and in the inv(16)/KitD816Y AML mouse model, but allosteric inhibition of Shp2 did not impair the clonogenic ability of normal bone marrow progenitors. Together, these results support the future use of SHP2 inhibitor combinations for clinical applications.
Significance:
These findings suggest that combined inhibition of SHP2 and FLT3 effectively treat FLT3-ITD–positive AML, highlighting the need for development of more potent SHP2 inhibitors and combination therapies for clinical applications.
Data from Targeting IGF Perturbs Global Replication through Ribonucleotide Reductase Dysfunction
Authors: Rieunier Guillaume , Wu Xiaoning , Harris Letitia E. , Mills Jack V. , Nandakumar Ashwin , Colling Laura , Seraia Elena , Hatch Stephanie B. , Ebner Daniel V. , Folkes Lisa K. , Weyer-Czernilofsky Ulrike , Bogenrieder Thomas , Ryan Anderson J. , Macaulay Valentine M.
Published: March 2023

Abstract
Inhibition of IGF receptor (IGF1R) delays repair of radiation-induced DNA double-strand breaks (DSB), prompting us to investigate whether IGF1R influences endogenous DNA damage. Here we demonstrate that IGF1R inhibition generates endogenous DNA lesions protected by 53BP1 bodies, indicating under-replicated DNA. In cancer cells, inhibition or depletion of IGF1R delayed replication fork progression accompanied by activation of ATR–CHK1 signaling and the intra-S-phase checkpoint. This phenotype reflected unanticipated regulation of global replication by IGF1 mediated via AKT, MEK/ERK, and JUN to influence expression of ribonucleotide reductase (RNR) subunit RRM2. Consequently, inhibition or depletion of IGF1R downregulated RRM2, compromising RNR function and perturbing dNTP supply. The resulting delay in fork progression and hallmarks of replication stress were rescued by RRM2 overexpression, confirming RRM2 as the critical factor through which IGF1 regulates replication. Suspecting existence of a backup pathway protecting from toxic sequelae of replication stress, targeted compound screens in breast cancer cells identified synergy between IGF inhibition and ATM loss. Reciprocal screens of ATM-proficient/deficient fibroblasts identified an IGF1R inhibitor as the top hit. IGF inhibition selectively compromised growth of ATM-null cells and spheroids and caused regression of ATM-null xenografts. This synthetic-lethal effect reflected conversion of single-stranded lesions in IGF-inhibited cells into toxic DSBs upon ATM inhibition. Overall, these data implicate IGF1R in alleviating replication stress, and the reciprocal IGF:ATM codependence we identify provides an approach to exploit this effect in ATM-deficient cancers.
Significance:
This study identifies regulation of ribonucleotide reductase function and dNTP supply by IGFs and demonstrates that IGF axis blockade induces replication stress and reciprocal codependence on ATM.
Data from The Common Germline TP53-R337H Mutation Is Hypomorphic and Confers Incomplete Penetrance and Late Tumor Onset in a Mouse Model
Authors: Jeffers John R. , Pinto Emilia M. , Rehg Jerold E. , Clay Michael R. , Wang Jinling , Neale Geoffrey , Heath Richard J. , Lozano Guillermina , Lalli Enzo , Figueiredo Bonald C. , Pappo Alberto S. , Rodriguez-Galindo Carlos , Chen Wenan , Pounds Stanley , Ribeiro Raul C. , Zambetti Gerard P.
Published: March 2023

Abstract
The TP53-R337H founder mutation exists at a high frequency throughout southern Brazil and represents one of the most common germline TP53 mutations reported to date. It was identified in pediatric adrenocortical tumors in families with a low incidence of cancer. The R337H mutation has since been found in association with early-onset breast cancers and Li–Fraumeni syndrome (LFS). To study this variability in tumor susceptibility, we generated a knockin mutant p53 mouse model (R334H). Endogenous murine p53-R334H protein was naturally expressed at high levels in multiple tissues and was functionally compromised in a tissue- and stress-specific manner. Mutant p53-R334H mice developed tumors with long latency and incomplete penetrance, consistent with many human carriers being at a low but elevated risk for cancer. These findings suggest the involvement of additional cooperating genetic alterations when TP53-R337H occurs in the context of LFS, which has important implications for genetic counseling and long-term clinical follow-up.
Significance:
A p53-R334H knockin mouse serves as an important model for studying the most common inherited germline TP53 mutation (R337H) that is associated with variable tumor susceptibility.