bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Extracellular Vesicle–Packaged CDH11 and ITGA5 Induce the Premetastatic Niche for Bone Colonization of Breast Cancer Cells
Authors: Li Xiao-Qing , Zhang Rui , Lu Hong , Yue Xiao-Min , Huang Yu-Fan
Published: March 2024

Abstract
Although most breast cancer metastases in bone cause osteolytic lesions, the osteogenic niche has commonly been described as an initiator of early-stage bone colonization of disseminated cancer cells. Tumor cell–derived extracellular vesicles (EV) have been shown to determine the organotropism of cancer cells by transferring their cargo, such as nucleic acids and proteins, to resident cells at future metastatic sites and preparing a favorable premetastatic niche. Runt-related transcription factor 2 (RUNX2) and its regulated genes have been shown to facilitate the acquisition of osteomimetic features and to enhance the bone metastatic potential of breast cancer cells. In this study, we present in vivo and in vitro evidence to clarify the role of EVs released by breast cancer cells with high RUNX2 expression in the education of osteoblasts to form an osteogenic premetastatic niche. Furthermore, different extracellular vesicular proteins were identified that mediate events subsequent to the specific recognition of tumor-derived EVs by osteoblasts via cadherin 11 (CDH11) and the induction of the osteogenic premetastatic niche by integrin α5 (ITGA5). CDH11high/ITGA5high EVs were demonstrated to be responsible for the formation of a premetastatic niche that facilitates RUNX2 high-expressing breast cancer cell colonization in bone, revealing a potential EV-based premetastatic niche blockage strategy.
Significance:
This study provides mechanistic insights into the generation of an osteogenic premetastatic niche by breast cancer–derived EVs and identifies potential EV-derived diagnostic biomarkers and targets for breast cancer bone metastasis.
Data from A Pan-Cancer Immunogenomic Atlas for Immune Checkpoint Blockade Immunotherapy
Authors: Yang Jing , Zhao Shilin , Wang Jing , Sheng Quanhu , Liu Qi , Shyr Yu
Published: March 2024

Abstract
The ability to identify robust genomic signatures that predict response to immune checkpoint blockade is restricted by limited sample sizes and ungeneralizable performance across cohorts. To address these challenges, we established Cancer-Immu (http://bioinfo.vanderbilt.edu/database/Cancer-Immu/), a comprehensive platform that integrates large-scale multidimensional omics data, including genetic, bulk, and single-cell transcriptomic, proteomic, and dynamic genomic profiles, with clinical phenotypes to explore consistent and rare immunogenomic connections. Currently Cancer-Immu has incorporated data for 3,652 samples for 16 cancer types. It provides easy access to immunogenomic data and empowers researchers to translate omics datasets into biological insights and clinical applications.
Significance:
Cancer-Immu is a comprehensive functional portal for unraveling immune-genomic connections to improve immune checkpoint blockade–based cancer immunotherapy.
Data from HSP90 Mediates IFNγ-Induced Adaptive Resistance to Anti-PD-1 Immunotherapy
Authors: Liu Ke , Huang Jun , Liu Jiao , Li Changfeng , Kroemer Guido , Tang Daolin , Kang Rui
Published: March 2024

Abstract
Constitutive or acquired resistance is a major problem limiting the clinical success of anticancer immunotherapies targeting the PD-1/PD-L1 interaction. Here, we report that the molecular chaperone HSP90 is a key mediator of IFNγ-induced adaptive immune resistance. An unbiased screen of 17 cancer cell lines or primary cancer cells identified novel metabolic agents, especially HSP90 inhibitors, that blocked the upregulation of immune checkpoints (IDO1 and PD-L1) induced by IFNγ. Subsequent quantitative mass spectrometry combined with functional rescue analysis revealed that IFNγ-induced immune checkpoint expression requires increased protein stability of the transcription factor STAT1, mediated by the HSP90–SUGT1 chaperone complex. Expression of dominant-negative HSP90 (D88N) resulted in inhibition of STAT1-mediated IFNγ signaling. The upregulation of IDO1 in cancer cells acted as an immunosuppressive feedback mechanism to limit the proliferation and function of cytotoxic CD8+ T lymphocytes through iron-dependent kynurenine production and subsequent TSPAN5-mediated kynurenine secretion. The effectiveness and safety of combinations of anti-PD-1 immunotherapy with iron chelation or pharmacologic inhibitors of HSP90 or IDO1 was confirmed in xenograft, orthotopic, and transgenic mouse models of pancreatic cancer. These findings support the rationale for future clinical trials in which widely used immunotherapies are combined with additional molecules that intercept resistance by iron chelation, IDO1 inhibition, or HSP90 neutralization.
Significance:
This study reveals an HSP90-centric, iron-modulated mechanism that confers immunosuppression, offering potential therapeutic targets for interfering with acquired resistance to the most prevalent anticancer immunotherapies.
Data from Targeting BCAT1 Combined with α-Ketoglutarate Triggers Metabolic Synthetic Lethality in Glioblastoma
Authors: Zhang Bo , Peng Hui , Zhou Mi , Bao Lei , Wang Chenliang , Cai Feng , Zhang Hongxia , Wang Jennifer E. , Niu Yanling , Chen Yan , Wang Yijie , Hatanpaa Kimmo J. , Copland John A. , DeBerardinis Ralph J. , Wang Yingfei , Luo Weibo
Published: March 2024

Abstract
Branched-chain amino acid transaminase 1 (BCAT1) is upregulated selectively in human isocitrate dehydrogenase (IDH) wildtype (WT) but not mutant glioblastoma multiforme (GBM) and promotes IDHWT GBM growth. Through a metabolic synthetic lethal screen, we report here that α-ketoglutarate (AKG) kills IDHWT GBM cells when BCAT1 protein is lost, which is reversed by reexpression of BCAT1 or supplementation with branched-chain α-ketoacids (BCKA), downstream metabolic products of BCAT1. In patient-derived IDHWT GBM tumors in vitro and in vivo, cotreatment of BCAT1 inhibitor gabapentin and AKG resulted in synthetic lethality. However, AKG failed to evoke a synthetic lethal effect with loss of BCAT2, BCKDHA, or GPT2 in IDHWT GBM cells. Mechanistically, loss of BCAT1 increased the NAD+/NADH ratio but impaired oxidative phosphorylation, mTORC1 activity, and nucleotide biosynthesis. These metabolic alterations were synergistically augmented by AKG treatment, thereby causing mitochondrial dysfunction and depletion of cellular building blocks, including ATP, nucleotides, and proteins. Partial restoration of ATP, nucleotides, proteins, and mTORC1 activity by BCKA supplementation prevented IDHWT GBM cell death conferred by the combination of BCAT1 loss and AKG. These findings define a targetable metabolic vulnerability in the most common subset of GBM that is currently incurable.
Significance:
Metabolic synthetic lethal screening in IDHWT glioblastoma defines a vulnerability to ΑΚG following BCAT1 loss, uncovering a therapeutic strategy to improve glioblastoma treatment.

See related commentary by Meurs and Nagrath, p. 2354
Data from GLS2 Is a Tumor Suppressor and a Regulator of Ferroptosis in Hepatocellular Carcinoma
Authors: Suzuki Sawako , Venkatesh Divya , Kanda Hiroaki , Nakayama Akitoshi , Hosokawa Hiroyuki , Lee Eunyoung , Miki Takashi , Stockwell Brent R. , Yokote Koutaro , Tanaka Tomoaki , Prives Carol
Published: March 2024

Abstract
Glutamine synthase 2 (GLS2) is a key regulator of glutaminolysis and has been previously implicated in activities consistent with tumor suppression. Here we generated Gls2 knockout (KO) mice that develop late-occurring B-cell lymphomas and hepatocellular carcinomas (HCC). Further, Gls2 KO mice subjected to the hepatocarcinogenic Stelic Animal Model (STAM) protocol produce larger HCC tumors than seen in wild-type (WT) mice. GLS2 has been shown to promote ferroptosis, a form of cell death characterized by iron-dependent accumulation of lipid peroxides. In line with this, GLS2 deficiency, either in cells derived from Gls2 KO mice or in human cancer cells depleted of GLS2, conferred significant resistance to ferroptosis. Mechanistically, GLS2, but not GLS1, increased lipid reactive oxygen species (ROS) production by facilitating the conversion of glutamate to α-ketoglutarate (αKG), thereby promoting ferroptosis. Ectopic expression of WT GLS2 in a human hepatic adenocarcinoma xenograft model significantly reduced tumor size; this effect was nullified by either expressing a catalytically inactive form of GLS2 or by blocking ferroptosis. Furthermore, analysis of cancer patient datasets supported a role for GLS2-mediated regulation of ferroptosis in human tumor suppression. These data suggest that GLS2 is a bona fide tumor suppressor and that its ability to favor ferroptosis by regulating glutaminolysis contributes to its tumor suppressive function.
Significance:
This study demonstrates that the key regulator of glutaminolysis, GLS2, can limit HCC in vivo by promoting ferroptosis through αKG-dependent lipid ROS, which in turn might lay the foundation for a novel therapeutic approach.
Data from FOXR2 Is an Epigenetically Regulated Pan-Cancer Oncogene That Activates ETS Transcriptional Circuits
Authors: Tsai Jessica W. , Cejas Paloma , Wang Dayle K. , Patel Smruti , Wu David W. , Arounleut Phonepasong , Wei Xin , Zhou Ningxuan , Syamala Sudeepa , Dubois Frank P.B. , Crane Alexander , Pelton Kristine , Vogelzang Jayne , Sousa Cecilia , Baguette Audrey , Chen Xiaolong , Condurat Alexandra L. , Dixon-Clarke Sarah E. , Zhou Kevin N. , Lu Sophie D. , Gonzalez Elizabeth M. , Chacon Madison S. , Digiacomo Jeromy J. , Kumbhani Rushil , Novikov Dana , Hunter J'Ya , Tsoli Maria , Ziegler David S. , Dirksen Uta , Jager Natalie , Balasubramanian Gnana Prakash , Kramm Christof M. , Nathrath Michaela , Bielack Stefan , Baker Suzanne J. , Zhang Jinghui , McFarland James M. , Getz Gad , Aguet François , Jabado Nada , Witt Olaf , Pfister Stefan M. , Ligon Keith L. , Hovestadt Volker , Kleinman Claudia L. , Long Henry , Jones David T.W. , Bandopadhayay Pratiti , Phoenix Timothy N.
Published: March 2024

Abstract
Forkhead box R2 (FOXR2) is a forkhead transcription factor located on the X chromosome whose expression is normally restricted to the testis. In this study, we performed a pan-cancer analysis of FOXR2 activation across more than 10,000 adult and pediatric cancer samples and found FOXR2 to be aberrantly upregulated in 70% of all cancer types and 8% of all individual tumors. The majority of tumors (78%) aberrantly expressed FOXR2 through a previously undescribed epigenetic mechanism that involves hypomethylation of a novel promoter, which was functionally validated as necessary for FOXR2 expression and proliferation in FOXR2-expressing cancer cells. FOXR2 promoted tumor growth across multiple cancer lineages and co-opted ETS family transcription circuits across cancers. Taken together, this study identifies FOXR2 as a potent and ubiquitous oncogene that is epigenetically activated across the majority of human cancers. The identification of hijacking of ETS transcription circuits by FOXR2 extends the mechanisms known to active ETS transcription factors and highlights how transcription factor families cooperate to enhance tumorigenesis.
Significance:
This work identifies a novel promoter that drives aberrant FOXR2 expression and delineates FOXR2 as a pan-cancer oncogene that specifically activates ETS transcriptional circuits across human cancers.

See related commentary by Liu and Northcott, p. 2977
Data from Oxidative Phosphorylation Is a Metabolic Vulnerability in Chemotherapy-Resistant Triple-Negative Breast Cancer
Authors: Evans Kurt W. , Yuca Erkan , Scott Stephen S. , Zhao Ming , Paez Arango Natalia , Cruz Pico Christian X. , Saridogan Turcin , Shariati Maryam , Class Caleb A. , Bristow Christopher A. , Vellano Christopher P. , Zheng Xiaofeng , Gonzalez-Angulo Ana Maria , Su Xiaoping , Tapia Coya , Chen Ken , Akcakanat Argun , Lim Bora , Tripathy Debu , Yap Timothy A. , Francesco Maria Emilia Di , Draetta Giulio F. , Jones Philip , Heffernan Timothy P. , Marszalek Joseph R. , Meric-Bernstam Funda
Published: March 2024

Abstract
Oxidative phosphorylation (OXPHOS) is an active metabolic pathway in many cancers. RNA from pretreatment biopsies from patients with triple-negative breast cancer (TNBC) who received neoadjuvant chemotherapy demonstrated that the top canonical pathway associated with worse outcome was higher expression of OXPHOS signature. IACS-10759, a novel inhibitor of OXPHOS, stabilized growth in multiple TNBC patient-derived xenografts (PDX). On gene expression profiling, all of the sensitive models displayed a basal-like 1 TNBC subtype. Expression of mitochondrial genes was significantly higher in sensitive PDXs. An in vivo functional genomics screen to identify synthetic lethal targets in tumors treated with IACS-10759 found several potential targets, including CDK4. We validated the antitumor efficacy of the combination of palbociclib, a CDK4/6 inhibitor, and IACS-10759 in vitro and in vivo. In addition, the combination of IACS-10759 and multikinase inhibitor cabozantinib had improved antitumor efficacy. Taken together, our data suggest that OXPHOS is a metabolic vulnerability in TNBC that may be leveraged with novel therapeutics in combination regimens.
Significance:
These findings suggest that triple-negative breast cancer is highly reliant on OXPHOS and that inhibiting OXPHOS may be a novel approach to enhance efficacy of several targeted therapies.
Data from The Mutational Signature Comprehensive Analysis Toolkit (musicatk) for the Discovery, Prediction, and Exploration of Mutational Signatures
Authors: Chevalier Aaron , Yang Shiyi , Khurshid Zainab , Sahelijo Nathan , Tong Tong , Huggins Jonathan H. , Yajima Masanao , Campbell Joshua D.
Published: March 2024

Abstract
Mutational signatures are patterns of somatic alterations in the genome caused by carcinogenic exposures or aberrant cellular processes. To provide a comprehensive workflow for preprocessing, analysis, and visualization of mutational signatures, we created the Mutational Signature Comprehensive Analysis Toolkit (musicatk) package. musicatk enables users to select different schemas for counting mutation types and to easily combine count tables from different schemas. Multiple distinct methods are available to deconvolute signatures and exposures or to predict exposures in individual samples given a pre-existing set of signatures. Additional exploratory features include the ability to compare signatures to the Catalogue Of Somatic Mutations In Cancer (COSMIC) database, embed tumors in two dimensions with uniform manifold approximation and projection, cluster tumors into subgroups based on exposure frequencies, identify differentially active exposures between tumor subgroups, and plot exposure distributions across user-defined annotations such as tumor type. Overall, musicatk will enable users to gain novel insights into the patterns of mutational signatures observed in cancer cohorts.
Significance:
The musicatk package empowers researchers to characterize mutational signatures and tumor heterogeneity with a comprehensive set of preprocessing utilities, discovery and prediction tools, and multiple functions for downstream analysis and visualization.
Data from Inactivation of Mirk/Dyrk1b Kinase Targets Quiescent Pancreatic Cancer Cells
Authors: Ewton Daina Z. , Hu Jing , Vilenchik Maria , Deng Xiaobing , Luk Kin-chun , Polonskaia Ann , Hoffman Ann F. , Zipf Karen , Boylan John F. , Friedman Eileen A.
Published: March 2024

Abstract
A major problem in the treatment of cancer arises from quiescent cancer cells that are relatively insensitive to most chemotherapeutic drugs and radiation. Such residual cancer cells can cause tumor regrowth or recurrence when they reenter the cell cycle. Earlier studies showed that levels of the serine/theronine kinase Mirk/dyrk1B are elevated up to 10-fold in quiescent G0 tumor cells. Mirk uses several mechanisms to block cell cycling, and Mirk increases expression of antioxidant genes that decrease reactive oxygen species (ROS) levels and increase quiescent cell viability. We now show that a novel small molecule Mirk kinase inhibitor blocked tumor cells from undergoing reversible arrest in a quiescent G0 state and enabled some cells to exit quiescence. The inhibitor increased cycling in Panc1, AsPc1, and SW620 cells that expressed Mirk, but not in HCT116 cells that did not. Mirk kinase inhibition elevated ROS levels and DNA damage detected by increased phosphorylation of the histone protein H2AX and by S-phase checkpoints. The Mirk kinase inhibitor increased cleavage of the apoptotic proteins PARP and caspase 3, and increased tumor cell kill several-fold by gemcitabine and cisplatin. A phenocopy of these effects occurred following Mirk depletion, showing drug specificity. In previous studies Mirk knockout or depletion had no detectable effect on normal tissue, suggesting that the Mirk kinase inhibitor could have a selective effect on cancer cells expressing elevated levels of Mirk kinase. Mol Cancer Ther; 10(11); 2104–14. ©2011 AACR.
Data from Ovarian Cancer Stem Cell–Like Side Populations Are Enriched Following Chemotherapy and Overexpress EZH2
Authors: Rizzo Siân , Hersey Jenny M. , Mellor Paul , Dai Wei , Santos-Silva Alessandra , Liber Daniel , Luk Louisa , Titley Ian , Carden Craig P , Box Garry , Hudson David L. , Kaye Stanley B. , Brown Robert
Published: March 2024

Abstract
Platinum-based chemotherapy, with cytoreductive surgery, is the cornerstone of treatment of advanced ovarian cancer; however, acquired drug resistance is a major clinical obstacle. It has been proposed that subpopulations of tumor cells with stem cell–like properties, such as so-called side populations (SP) that overexpress ABC drug transporters, can sustain the growth of drug-resistant tumor cells, leading to tumor recurrence following chemotherapy. The histone methyltransferase EZH2 is a key component of the polycomb-repressive complex 2 required for maintenance of a stem cell state, and overexpression has been implicated in drug resistance and shorter survival of ovarian cancer patients. We observed higher percentage SP in ascites from patients that have relapsed following chemotherapy compared with chemonaive patients, consistent with selection for this subpopulation during platinum-based chemotherapy. Furthermore, ABCB1 (P-glycoprotein) and EZH2 are consistently overexpressed in SP compared with non-SP from patients' tumor cells. The siRNA knockdown of EZH2 leads to loss of SP in ovarian tumor models, reduced anchorage-independent growth, and reduced tumor growth in vivo. Together, these data support a key role for EZH2 in the maintenance of a drug-resistant, tumor-sustaining subpopulation of cells in ovarian cancers undergoing chemotherapy. As such, EZH2 is an important target for anticancer drug development. Mol Cancer Ther; 10(2); 325–35. ©2010 AACR.
Data from Cdk4/6 Inhibition Induces Epithelial–Mesenchymal Transition and Enhances Invasiveness in Pancreatic Cancer Cells
Authors: Liu Fang , Korc Murray
Published: March 2024

Abstract
Aberrant activation of Cyclin D-Cdk4/6 signaling pathway is commonly found in pancreatic ductal adenocarcinoma (PDAC). Here, we show that PD-0332991, a highly specific inhibitor for Cdk4 and Cdk6, exerted growth inhibitory effects on three human PDAC cell lines. Microarray analysis revealed that PD-0332991 downregulated cell-cycle–related genes, but upregulated genes implicated in extracellular matrix (ECM) remodeling and pancreatic cancer cell invasion and metastasis. Moreover, PD-0332991 enhanced invasion in TGF-β–responsive PDAC cell lines that harbor a wild-type SMAD4 gene (COLO-357, PANC-1), but not in TGF-β–resistant AsPC-1 cells that harbor a mutated SMAD4. PD-0332991 also induced epithelial–mesenchymal transition (EMT) in COLO-357 and PANC-1, but not in AsPC-1 cells. Inhibition of CDK4/6 using shRNA mimicked the effects of PD-0332991 on EMT induction. Furthermore, PD-0332991 increased Smad transcriptional activity in luciferase readout assays and activated TGF-β signaling. SB-505124, an inhibitor of the type-I TGF-β receptor (TβRI) kinase, completely blocked EMT induction by PD-0332991. When combined with PD-0332991, SB-505124 inhibited the growth of COLO-357 and PANC-1 cells. Taken together, these data suggest that anti-Cdk4/6 therapy could induce EMT and enhance pancreatic cancer cell invasion by activating Smad-dependent TGF-β signaling, and that combining PD-0332991 and SB-505124 may represent a novel therapeutic strategy in PDAC. Mol Cancer Ther; 11(10); 2138–48. ©2012 AACR.
Data from Targeting Tyrosine Phosphorylation of PCNA Inhibits Prostate Cancer Growth
Authors: Zhao Huajun , Lo Yuan-Hung , Ma Li , Waltz Susan E. , Gray Jerilyn K. , Hung Mien-Chie , Wang Shao-Chun
Published: March 2024

Abstract
The proliferation cell nuclear antigen (PCNA) is a critical protein required for DNA replication in proliferating cells including cancer cells. However, direct inhibition of PCNA in cancer cells has been difficult due to the lack of targetable sites. We previously reported that phosphorylation of tyrosine 211 (Y211) on PCNA is important for the proliferative function of PCNA when this protein is associated with the chromatin in cancer cells. Here, we show that the Y211 phosphorylation of PCNA is a frequent event in advanced prostate cancer. To explore the potential of this signaling event in inhibition of cancer cell growth, we used a synthetic peptide, the Y211F peptide, which when present inhibits phosphorylation of Y211 on endogenous PCNA. Treatment with this peptide, but not a scrambled control peptide, resulted in S-phase arrest, inhibition of DNA synthesis, and enhanced cell death in a panel of human prostate cancer cell lines. In addition, treatment with the Y211F peptide led to decreased tumor growth in PC3-derived xenograft tumors in vivo in nude mice. Our study shows for the first time that PCNA phosphorylation at Y211 is a frequent and biologically important signaling event in prostate cancer. This study also shows a proof of concept that Y211 phosphorylation of PCNA may be used as a therapeutic target in prostate cancer cells, including cells of advanced cancers that are refractory to standard hormonal therapies. Mol Cancer Ther; 10(1); 29–36. ©2011 AACR.
Data from A YKL-40–Neutralizing Antibody Blocks Tumor Angiogenesis and Progression: A Potential Therapeutic Agent in Cancers
Authors: Faibish Michael , Francescone Ralph , Bentley Brooke , Yan Wei , Shao Rong
Published: March 2024

Abstract
Accumulating evidence has indicated that expression levels of YKL-40, a secreted glycoprotein, were elevated in multiple advanced human cancers. Recently, we have identified an angiogenic role of YKL-40 in cancer development. However, blockade of the function of YKL-40, which implicates therapeutic value, has not been explored yet. Our current study sought to establish a monoclonal anti–YKL-40 antibody as a neutralizing antibody for the purpose of blocking tumor angiogenesis and metastasis. A mouse monoclonal anti–YKL-40 antibody (mAY) exhibited specific binding with recombinant YKL-40 and with YKL-40 secreted from osteoblastoma cells MG-63 and brain tumor cells U87. In the functional analysis, we found that mAY inhibited tube formation of microvascular endothelial cells in Matrigel induced by conditioned medium of MG-63 and U87 cells, as well as recombinant YKL-40. mAY also abolished YKL-40–induced activation of the membrane receptor VEGF receptor 2 (Flk-1/KDR) and intracellular signaling mitogen-activated protein (MAP) kinase extracellular signal–regulated kinase (Erk) 1 and Erk 2. In addition, mAY enhanced cell death response of U87 line to γ-irradiation through decreased expression of pAKT and AKT and accordingly, abrogated angiogenesis induced by the conditioned medium of U87 cells in which YKL-40 levels were elevated by treatment with γ-irradiation. Furthermore, treatment of xenografted tumor mice with mAY restrained tumor growth, angiogenesis, and progression. Taken together, this study has shown the therapeutic use for the mAY in treatment of tumor angiogenesis and metastasis. Mol Cancer Ther; 10(5); 742–51. ©2011 AACR.
Data from Exon 11 Skipping of E-Cadherin RNA Downregulates Its Expression in Head and Neck Cancer Cells
Authors: Sharma Sanjai , Liao Wei , Zhou Xiaofeng , Wong David T.W. , Lichtenstein Alan
Published: March 2024

Abstract
E-cadherin is an important tumor suppressor gene whose expression is lost when cells acquire a metastatic phenotype. We analyzed the role of E-cadherin missplicing as a mechanism of its downregulation by analyzing a misspliced E-cadherin transcript that lacks exon 11 of this gene. This results in a frameshift and a premature termination codon that targets this transcript for degradation. Tumor tissues, including breast (20%, n = 9), prostate (30%, n = 9) and head and neck (75%, n = 8) cancer, express the exon 11-skipped transcripts (vs. nonmalignant controls) and its levels inversely correlate with E-cadherin expression. This is a novel mechanism of E-cadherin downregulation by missplicing in tumor cells, which is observed in highly prevalent human tumors. In the head and neck cancer model, nontumorigenic keratinocytes express exon 11–skipped splice product two- to sixfold lower than the head and neck tumor cell lines. Mechanistic studies reveal that SFRS2 (SC35), a splicing factor, as one of the regulators that increases missplicing and downregulates E-cadherin expression. Furthermore, this splicing factor was found to be overexpressed in 5 of 7 head and neck cell lines and primary head and neck tumors. Also, methylation of E-cadherin gene acts as a regulator of this aberrant splicing process. In 2 head and neck cell lines, wild-type transcript expression increased 16- to 25-folds, whereas the percentage of exon 11-skipped transcripts in both the cell lines decreased five- to 30-folds when cells were treated with a hypomethylating agent, azacytidine. Our findings reveal that promoter methylation and an upregulated splicing factor (SFRS2) are involved in the E-cadherin missplicing in tumors. Mol Cancer Ther; 10(9); 1751–9. ©2011 AACR.
Data from The Bcl-2/Bcl-XL/Bcl-w Inhibitor, Navitoclax, Enhances the Activity of Chemotherapeutic Agents In Vitro and In Vivo
Authors: Chen Jun , Jin Sha , Abraham Vivek , Huang Xiaoli , Liu Bernard , Mitten Michael J. , Nimmer Paul , Lin Xiaoyu , Smith Morey , Shen Yu , Shoemaker Alexander R. , Tahir Stephen K. , Zhang Haichao , Ackler Scott L. , Rosenberg Saul H. , Maecker Heather , Sampath Deepak , Leverson Joel D. , Tse Chris , Elmore Steven W.
Published: March 2024

Abstract
The ability of a cancer cell to avoid apoptosis is crucial to tumorigenesis and can also contribute to chemoresistance. The Bcl-2 family of prosurvival proteins (Bcl-2, Bcl-XL, Bcl-w, Mcl-1, and A1) plays a key role in these processes. We previously reported the discovery of ABT-263 (navitoclax), a potent small-molecule inhibitor of Bcl-2, Bcl-XL, and Bcl-w. While navitoclax exhibits single-agent activity in tumors dependent on Bcl-2 or Bcl-XL for survival, the expression of Mcl-1 has been shown to confer resistance to navitoclax, most notably in solid tumors. Thus, therapeutic agents that can downregulate or neutralize Mcl-1 are predicted to synergize potently with navitoclax. Here, we report the activity of navitoclax in combination with 19 clinically relevant agents across a panel of 46 human solid tumor cell lines. Navitoclax broadly enhanced the activity of multiple therapeutic agents in vitro and enhanced efficacy of both docetaxel and erlotinib in xenograft models. The ability of navitoclax to synergize with docetaxel or erlotinib corresponded to an altered sensitivity of the mitochondria toward navitoclax, which was associated with the downmodulation of Mcl-1 and/or upregulation of Bim. These data provide a rationale to interrogate these combinations clinically. Mol Cancer Ther; 10(12); 2340–9. ©2011 AACR.
Data from Overexpression of Asparagine Synthetase and Matrix Metalloproteinase 19 Confers Cisplatin Sensitivity in Nasopharyngeal Carcinoma Cells
Authors: Liu Ran-Yi , Dong Zizheng , Liu Jianguo , Zhou Ling , Huang Wenlin , Khoo Sok Kean , Zhang Zhongfa , Petillo David , Teh Bin Tean , Qian Chao-Nan , Zhang Jian-Ting
Published: March 2024

Abstract
Platinum-based concurrent chemoradiotherapy is considered a standard treatment approach for locoregionally advanced nasopharyngeal carcinoma. However, only a minority of patients benefit from this treatment regimen compared with radiotherapy alone. Identification of a set of molecular markers predicting sensitivity of platinum-based chemotherapy may contribute to personalized treatment of patients with nasopharyngeal carcinoma for better clinical outcome with less toxicity. Previously, we generated a cisplatin-sensitive nasopharyngeal carcinoma cell line, S16, by clonal selection from CNE-2 cells and found that eIF3a is upregulated and contributes to cisplatin sensitivity by downregulating the synthesis of nucleotide excision repair proteins. In this study, we conducted a gene expression profiling analysis and found three other genes, asparagine synthetase (ASNS), choriogonadotropin α subunit (CGA), and matrix metalloproteinase 19 (MMP19), that are upregulated in the cisplatin-sensitive S16 cells compared with the CNE-2 cells. However, only ASNS and MMP19, but not CGA, contributes to cisplatin sensitivity by potentiating cisplatin-induced DNA damage and apoptosis. Thus, ASNS and MMP19, along with eIF3a, are the sensitivity factors for cisplatin treatment and may serve as potential candidate molecular markers for predicting cisplatin sensitivity of advanced nasopharyngeal carcinoma. Mol Cancer Ther; 12(10); 2157–66. ©2013 AACR.
Data from Apigenin Induces Apoptosis in Human Leukemia Cells and Exhibits Anti-Leukemic Activity In Vivo
Authors: Budhraja Amit , Gao Ning , Zhang Zhuo , Son Young-Ok , Cheng Senping , Wang Xin , Ding Songze , Hitron Andrew , Chen Gang , Luo Jia , Shi Xianglin
Published: March 2024

Abstract
In this study, we investigated the functional role of Akt and c-jun-NH2-kinase (JNK) signaling cascades in apigenin-induced apoptosis in U937 human leukemia cells and anti-leukemic activity of apigenin in vivo. Apigenin induced apoptosis by inactivation of Akt with a concomitant activation of JNK, Mcl-1 and Bcl-2 downregulation, cytochrome c release from mitochondria, and activation of caspases. Constitutively active myristolated Akt prevented apigenin-induced JNK, caspase activation, and apoptosis. Conversely, LY294002 and a dominant-negative construct of Akt potentiated apigenin-induced apoptosis in leukemia cells. Interruption of the JNK pathway showed marked reduction in apigenin-induced caspase activation and apoptosis in leukemia cells. Furthermore, in vivo administration of apigenin resulted in attenuation of tumor growth in U937 xenografts accompanied by inactivation of Akt and activation of JNK. Attenuation of tumor growth in U937 xenografts by apigenin raises the possibility that apigenin may have clinical implications and can be further tested for incorporating in leukemia treatment regimens. Mol Cancer Ther; 11(1); 132–42. ©2011 AACR.
Data from Rapamycin Induces Bad Phosphorylation in Association with Its Resistance to Human Lung Cancer Cells
Authors: Liu Yan , Sun Shi-Yong , Owonikoko Taofeek K. , Sica Gabriel L. , Curran Walter J. , Khuri Fadlo R. , Deng Xingming
Published: March 2024

Abstract
Inhibition of mTOR signaling by rapamycin has been shown to activate extracellular signal-regulated kinase 1 or 2 (ERK1/2) and Akt in various types of cancer cells, which contributes to rapamycin resistance. However, the downstream effect of rapamycin-activated ERKs and Akt on survival or death substrate(s) remains unclear. We discovered that treatment of human lung cancer cells with rapamycin results in enhanced phosphorylation of Bad at serine (S) 112 and S136 but not S155 in association with activation of ERK1/2 and Akt. A higher level of Bad phosphorylation was observed in rapamycin-resistant cells compared with parental rapamycin-sensitive cells. Thus, Bad phosphorylation may contribute to rapamycin resistance. Mechanistically, rapamycin promotes Bad accumulation in the cytosol, enhances Bad/14-3-3 interaction, and reduces Bad/Bcl-XL binding. Rapamycin-induced Bad phosphorylation promotes its ubiquitination and degradation, with a significant reduction of its half-life (i.e., from 53.3–37.5 hours). Inhibition of MEK/ERK by PD98059 or depletion of Akt by RNA interference blocks rapamycin-induced Bad phosphorylation at S112 or S136, respectively. Simultaneous blockage of S112 and S136 phosphorylation of Bad by PD98059 and silencing of Akt significantly enhances rapamycin-induced growth inhibition in vitro and synergistically increases the antitumor efficacy of rapamycin in lung cancer xenografts. Intriguingly, either suppression of Bad phosphorylation at S112 and S136 sites or expression of the nonphosphorylatable Bad mutant (S112A/S136A) can reverse rapamycin resistance. These findings uncover a novel mechanism of rapamycin resistance, which may promote the development of new strategies for overcoming rapamycin resistance by manipulating Bad phosphorylation at S112 and S136 in human lung cancer. Mol Cancer Ther; 11(1); 45–56. ©2011 AACR.
Data from Low-Dose Metronomic Oral Dosing of a Prodrug of Gemcitabine (LY2334737) Causes Antitumor Effects in the Absence of Inhibition of Systemic Vasculogenesis
Authors: Francia Giulio , Shaked Yuval , Hashimoto Kae , Sun John , Yin Melissa , Cesta Carolyn , Xu Ping , Man Shan , Hackl Christina , Stewart Julie , Uhlik Mark , Dantzig Anne H. , Foster F. Stuart , Kerbel Robert S.
Published: March 2024

Abstract
Metronomic chemotherapy refers to the close, regular administration of conventional chemotherapy drugs at relatively low, minimally toxic doses, with no prolonged break periods; it is now showing encouraging results in various phase II clinical trials and is currently undergoing phase III trial evaluation. It is thought to cause antitumor effects primarily by antiangiogenic mechanisms, both locally by targeting endothelial cells of the tumor neovasculature and systemically by effects on bone marrow–derived cells, including circulating endothelial progenitor cells (CEP). Previous studies have shown reduction of CEPs by metronomic administration of a number of different chemotherapeutic drugs, including vinblastine, cyclophosphamide, paclitaxel, topotecan, and tegafur plus uracil (UFT). However in addition to, or even instead of, antiangiogenic effects, metronomic chemotherapy may cause suppression of tumor growth by other mechanisms such as stimulating cytotoxic T-cell responses or by direct antitumor effects. Here we report results evaluating the properties of metronomic administration of an oral prodrug of gemcitabine LY2334737 in nontumor–bearing mice and in preclinical models of human ovarian (SKOV3-13) and breast cancer (LM2-4) xenografts. Through daily gavage (at 6 mg/kg/d), the schedules tested were devoid of toxicity and caused antitumor effects; however, a suppressive effect on CEPs was not detected. Unexpectedly, metronomic LY2334737 administration caused increased blood flow in luciferase-tagged LM2-4 tumor xenografts, and this effect, readily measured using contrast micro-ultrasound, coincided with a relative increase in tumor bioluminescence. These results highlight the possibility of significant antitumor effects mediated by metronomic administration of some chemotherapy drugs without a concomitant inhibition of systemic angiogenesis. Mol Cancer Ther; 11(3); 680–9. ©2011 AACR.
Data from Sorafenib Sensitizes (−)-Gossypol-Induced Growth Suppression in Androgen-Independent Prostate Cancer Cells via Mcl-1 Inhibition and Bak Activation
Authors: Lian Jiqin , Ni Zhenhong , Dai Xufang , Su Chang , Smith Amber Rae , Xu Liang , He Fengtian
Published: March 2024

Abstract
The natural BH3-mimetic (−)-gossypol shows promising efficacy in ongoing phase II/III clinical trials for human prostate cancer. Here, we show for the first time, that treatment with (−)-gossypol and multikinase inhibitor sorafenib synergistically suppresses the growth of androgen-independent prostate cancer cells (AI-PC) in vitro and in vivo. Our data suggest that sorafenib attenuates (−)-gossypol-induced Mcl-1 upregulation in AI-PCs. In this way, it serves as a potent chemosensitizer to affect cell death. Interestingly, (−)-gossypol and sorafenib induce cell death via two distinct pathways among different AI-PCs; DU145 cells via apoptosis and PC-3 via autophagy. The appointed death pathway may depend on the level of proapoptotic protein Bak, although the level of antiapoptotic protein Bcl-2 plays some role in it. DU145 cells with high Bak level prefer apoptosis induction, whereas PC-3 cells with low Bak prefer the induction of autophagy. Furthermore, inhibiting nondominant death pathways, that is, autophagy in DU145 and apoptosis in PC-3, enhances cell killing by (−)-gossypol/sorafenib combination therapy. Ultimately, our data expose a new action for sorafenib as an enhancer of (−)-gossypol-induced cell growth suppression and reveal a novel cell death mode by Bak activation manners in AI-PCs. These new insights may facilitate the rational design of clinical trials by selecting patients most likely to benefit from the Bcl-2–targeted molecular therapy. Mol Cancer Ther; 11(2); 416–26. ©2011 AACR.
Data from Global Evaluation of Eph Receptors and Ephrins in Lung Adenocarcinomas Identifies EphA4 as an Inhibitor of Cell Migration and Invasion
Authors: Saintigny Pierre , Peng Shaohua , Zhang Li , Sen Banibrata , Wistuba Ignacio I. , Lippman Scott M. , Girard Luc , Minna John D. , Heymach John V. , Johnson Faye M.
Published: March 2024

Abstract
The Eph family of receptors is the largest family of receptor tyrosine kinases, but it remains poorly studied in lung cancer. We aimed to systematically explore the human Eph receptors and their ligands, the ephrins, in lung adenocarcinoma. The prognostic impact of Eph receptor and ephrin gene expression was analyzed using 2 independent cohorts of lung adenocarcinoma. Gene expression profiles in lung adenocarcinoma compared with normal adjacent lung were studied in 3 independent cohorts and in cell lines. Gene expression profiles were validated with quantitative polymerase chain reaction (qPCR) and Western blotting in cell lines. Functional studies to assess the role of Eph receptor A4 (EphA4) were carried out in vitro. The biological effects of EphA4 in lung cancer cell lines were assayed following overexpression and knockdown. Of the 11 Eph receptors and 8 ephrins analyzed, only EphA4 and ephrin A1 gene expression were consistently associated with an improved outcome in patients with lung adenocarcinoma. Expression levels of EphA4 by microarray correlated well with expression levels measured by qPCR and Western blotting. EphA4 overexpression reduced cell migration and invasion but did not affect cell cycle, apoptosis, or drug sensitivity. Surprisingly, EphA4 was expressed at higher levels in cancer compared with non-cancer tissues and cell lines. EphA4 gene expression is associated with an improved outcome in patients with resected lung adenocarcinoma, possibly by affecting cancer cell migration and invasion. Mol Cancer Ther; 11(9); 2021–32. ©2012 AACR.
Data from The Gamma Secretase Inhibitor MRK-003 Attenuates Pancreatic Cancer Growth in Preclinical Models
Authors: Mizuma Masamichi , Rasheed Zeshaan A. , Yabuuchi Shinichi , Omura Noriyuki , Campbell Nathaniel R. , de Wilde Roeland F. , De Oliveira Elizabeth , Zhang Qing , Puig Oscar , Matsui William , Hidalgo Manuel , Maitra Anirban , Rajeshkumar N.V.
Published: March 2024

Abstract
Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy, with most patients facing an adverse clinical outcome. Aberrant Notch pathway activation has been implicated in the initiation and progression of PDAC, specifically the aggressive phenotype of the disease. We used a panel of human PDAC cell lines as well as patient-derived PDAC xenografts to determine whether pharmacologic targeting of Notch pathway could inhibit PDAC growth and potentiate gemcitabine sensitivity. MRK-003, a potent and selective γ-secretase inhibitor, treatment resulted in the downregulation of nuclear Notch1 intracellular domain, inhibition of anchorage-independent growth, and reduction of tumor-initiating cells capable of extensive self-renewal. Pretreatment of PDAC cells with MRK-003 in cell culture significantly inhibited the subsequent engraftment in immunocompromised mice. MRK-003 monotherapy significantly blocked tumor growth in 5 of 9 (56%) PDAC xenografts. A combination of MRK-003 and gemcitabine showed enhanced antitumor effects compared with gemcitabine in 4 of 9 (44%) PDAC xenografts, reduced tumor cell proliferation, and induced both apoptosis and intratumoral necrosis. Gene expression analysis of untreated tumors indicated that upregulation of NF-κB pathway components was predictive of sensitivity to MRK-003, whereas upregulation in B-cell receptor signaling and nuclear factor erythroid-derived 2-like 2 pathway correlated with response to the combination of MRK-003 with gemcitabine. Our findings strengthen the rationale for small-molecule inhibition of Notch signaling as a therapeutic strategy in PDAC. Mol Cancer Ther; 11(9); 1999–2009. ©2012 AACR.
Data from IGFBP2/FAK Pathway Is Causally Associated with Dasatinib Resistance in Non–Small Cell Lung Cancer Cells
Authors: Lu Haibo , Wang Li , Gao Wen , Meng Jieru , Dai Bingbing , Wu Shuhong , Minna John , Roth Jack A. , Hofstetter Wayne L. , Swisher Stephen G. , Fang Bingliang
Published: March 2024

Abstract
Insulin-like growth factor (IGF)-binding protein-2 (IGFBP2) expression is increased in various types of cancers, including in a subset of patients with lung cancer. Because IGFBP2 is involved in signal transduction of some critical cancer-related pathways, we analyzed the association between IGFBP2 and response to pathway-targeted agents in seven human non–small cell lung cancer (NSCLC) cell lines. Western blot analysis and ELISA showed that four of the seven NSCLC cell lines analyzed expressed high levels of IGFBP2, whereas the remaining three had barely detectable IGFBP2. Susceptibilities of those seven cell lines to nine anticancer agents targeting to IGF1R, Src, FAK, MEK, and AKT were determined by a dose-dependent cell viability assay. The results showed that high IGFBP2 levels were associated with resistance to dasatinib and, to a lesser degree, to sacaratinib, but not to other agents. Ectopic IGFBP2 overexpression or knockdown revealed that changing IGFBP2 expression levels reversed dasatinib susceptibility phenotype, suggesting a causal relationship between IGFBP2 expression and dasatinib resistance. Molecular characterization revealed that focal adhesion kinase (FAK) activation was associated with increased IGFBP2 expression and partially contributed to IGFBP2-mediated dasatinib resistance. Treatment with a combination of dasatinib and FAK inhibitor led to enhanced antitumor activity in IGFBP2-overexpressing and dasatinib-resistant NSCLC cells in vitro and in vivo. Our results showed that the IGFBP2/FAK pathway is causally associated with dasatinib resistance and may be used as biomarkers for identification of dasatinib responders among patients with lung cancer. Simultaneous targeting on Src and FAK will likely improve the therapeutic efficacy of dasatinib for treatment of lung cancer. Mol Cancer Ther; 12(12); 2864–73. ©2013 AACR.
Data from Antitumor Activity of a Novel Bispecific Antibody That Targets the ErbB2/ErbB3 Oncogenic Unit and Inhibits Heregulin-Induced Activation of ErbB3
Authors: McDonagh Charlotte F. , Huhalov Alexandra , Harms Brian D. , Adams Sharlene , Paragas Violette , Oyama Shinji , Zhang Bo , Luus Lia , Overland Ryan , Nguyen Stephanie , Gu Jinming , Kohli Neeraj , Wallace Matt , Feldhaus Michael J. , Kudla Arthur J. , Schoeberl Birgit , Nielsen Ulrik B.
Published: March 2024

Abstract
The prevalence of ErbB2 amplification in breast cancer has resulted in the heavy pursuit of ErbB2 as a therapeutic target. Although both the ErbB2 monoclonal antibody trastuzumab and ErbB1/ErbB2 dual kinase inhibitor lapatinib have met with success in the clinic, many patients fail to benefit. In addition, the majority of patients who initially respond will unfortunately ultimately progress on these therapies. Activation of ErbB3, the preferred dimerization partner of ErbB2, plays a key role in driving ErbB2-amplified tumor growth, but we have found that current ErbB2-directed therapies are poor inhibitors of ligand-induced activation. By simulating ErbB3 inhibition in a computational model of ErbB2/ErbB3 receptor signaling, we predicted that a bispecific antibody that docks onto ErbB2 and subsequently binds to ErbB3 and blocks ligand-induced receptor activation would be highly effective in ErbB2-amplified tumors, with superior activity to a monospecific ErbB3 inhibitor. We have developed a bispecific antibody suitable for both large scale production and systemic therapy by generating a single polypeptide fusion protein of two human scFv antibodies linked to modified human serum albumin. The resulting molecule, MM-111, forms a trimeric complex with ErbB2 and ErbB3, effectively inhibiting ErbB3 signaling and showing antitumor activity in preclinical models that is dependent on ErbB2 overexpression. MM-111 can be rationally combined with trastuzumab or lapatinib for increased antitumor activity and may in the future complement existing ErbB2-directed therapies to treat resistant tumors or deter relapse. Mol Cancer Ther; 11(3); 582–93. ©2012 AACR.
Data from Ganetespib, a Unique Triazolone-Containing Hsp90 Inhibitor, Exhibits Potent Antitumor Activity and a Superior Safety Profile for Cancer Therapy
Authors: Ying Weiwen , Du Zhenjian , Sun Lijun , Foley Kevin P. , Proia David A. , Blackman Ronald K. , Zhou Dan , Inoue Takayo , Tatsuta Noriaki , Sang Jim , Ye Shuxia , Acquaviva Jamie , Ogawa Luisa Shin , Wada Yumiko , Barsoum James , Koya Keizo
Published: March 2024

Abstract
Targeted inhibition of the molecular chaperone Hsp90 results in the simultaneous blockade of multiple oncogenic signaling pathways and has, thus, emerged as an attractive strategy for the development of novel cancer therapeutics. Ganetespib (formerly known as STA-9090) is a unique resorcinolic triazolone inhibitor of Hsp90 that is currently in clinical trials for a number of human cancers. In the present study, we showed that ganetespib exhibits potent in vitro cytotoxicity in a range of solid and hematologic tumor cell lines, including those that express mutated kinases that confer resistance to small-molecule tyrosine kinase inhibitors. Ganetespib treatment rapidly induced the degradation of known Hsp90 client proteins, displayed superior potency to the ansamycin inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG), and exhibited sustained activity even with short exposure times. In vivo, ganetespib showed potent antitumor efficacy in solid and hematologic xenograft models of oncogene addiction, as evidenced by significant growth inhibition and/or regressions. Notably, evaluation of the microregional activity of ganetespib in tumor xenografts showed that ganetespib was efficiently distributed throughout tumor tissue, including hypoxic regions >150 μm from the microvasculature, to inhibit proliferation and induce apoptosis. Importantly, ganetespib showed no evidence of cardiac or liver toxicity. Taken together, this preclinical activity profile indicates that ganetespib may have broad application for a variety of human malignancies, and with select mechanistic and safety advantages over other first- and second-generation Hsp90 inhibitors. Mol Cancer Ther; 11(2); 475–84. ©2011 AACR.