bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Promoter Methylation Analysis Reveals That KCNA5 Ion Channel Silencing Supports Ewing Sarcoma Cell Proliferation
Authors: Ryland Katherine E. , Hawkins Allegra G. , Weisenberger Daniel J. , Punj Vasu , Borinstein Scott C. , Laird Peter W. , Martens Jeffrey R. , Lawlor Elizabeth R.
Published: March 2024

Abstract
Polycomb proteins are essential regulators of gene expression in stem cells and development. They function to reversibly repress gene transcription via posttranslational modification of histones and chromatin compaction. In many human cancers, genes that are repressed by polycomb in stem cells are subject to more stable silencing via DNA methylation of promoter CpG islands. Ewing sarcoma is an aggressive bone and soft-tissue tumor that is characterized by overexpression of polycomb proteins. This study investigates the DNA methylation status of polycomb target gene promoters in Ewing sarcoma tumors and cell lines and observes that the promoters of differentiation genes are frequent targets of CpG-island DNA methylation. In addition, the promoters of ion channel genes are highly differentially methylated in Ewing sarcoma compared with nonmalignant adult tissues. Ion channels regulate a variety of biologic processes, including proliferation, and dysfunction of these channels contributes to tumor pathogenesis. In particular, reduced expression of the voltage-gated Kv1.5 channel has been implicated in tumor progression. These data show that DNA methylation of the KCNA5 promoter contributes to stable epigenetic silencing of the Kv1.5 channel. This epigenetic repression is reversed by exposure to the DNA methylation inhibitor decitabine, which inhibits Ewing sarcoma cell proliferation through mechanisms that include restoration of the Kv1.5 channel function.

Implications: This study demonstrates that promoters of ion channels are aberrantly methylated in Ewing sarcoma and that epigenetic silencing of KCNA5 contributes to tumor cell proliferation, thus providing further evidence of the importance of ion channel dysregulation to tumorigenesis. Mol Cancer Res; 14(1); 26–34. ©2015 AACR.
Data from PTEN Is a Potent Suppressor of Small Cell Lung Cancer
Authors: Cui Min , Augert Arnaud , Rongione Michael , Conkrite Karina , Parazzoli Susan , Nikitin Alexander Yu. , Ingolia Nicholas , MacPherson David
Published: March 2024

Abstract
Small cell lung carcinoma (SCLC) is a highly metastatic tumor type with neuroendocrine features and a dismal prognosis. PTEN mutations and PIK3CA activating mutations have been reported in SCLC but the functional relevance of this pathway is unknown. The PTEN/PIK3CA pathway was interrogated using an AdenoCre-driven mouse model of SCLC harboring inactivated Rb and p53. Inactivation of one allele of PTEN in Rb/p53-deleted mice led to accelerated SCLC with frequent metastasis to the liver. In contrast with the high mutation burden reported in human SCLC, exome analyses revealed a low number of protein-altering mutations in mouse SCLC. Inactivation of both alleles of PTEN in the Rb/p53-deleted system led to nonmetastatic adenocarcinoma with neuroendocrine differentiation. This study reveals a critical role for the PTEN/PI3K pathway in both SCLC and lung adenocarcinoma and provides an ideal system to test the phosphoinositide 3-kinase (PI3K) pathway inhibitors as targeted therapy for subsets of patients with SCLC.

Implications: The ability of PTEN inactivation to accelerate SCLC in a genetic mouse model suggests that targeting the PTEN pathway is a therapeutic option for a subset of human patients with SCLC.

Visual Overview: http://mcr.aacrjournals.org/content/early/2014/04/28/1541-7786.MCR-13-0554/F1.large.jpg. Mol Cancer Res; 12(5); 654–9. ©2014 AACR.
Data from A DNA-binding Molecule Targeting the Adaptive Hypoxic Response in Multiple Myeloma Has Potent Antitumor Activity
Authors: Mysore Veena S. , Szablowski Jerzy , Dervan Peter B. , Frost Patrick J.
Published: March 2024

Abstract
Multiple myeloma is incurable and invariably becomes resistant to chemotherapy. Although the mechanisms remain unclear, hypoxic conditions in the bone marrow have been implicated in contributing to multiple myeloma progression, angiogenesis, and resistance to chemotherapy. These effects occur via adaptive cellular responses mediated by hypoxia-inducible transcription factors (HIF), and targeting HIFs can have anticancer effects in both solid and hematologic malignancies. Here, it was found that in most myeloma cell lines tested, HIF1α, but not HIF2α expression was oxygen dependent, and this could be explained by the differential expression of the regulatory prolyl hydroxylase isoforms. The anti–multiple myeloma effects of a sequence-specific DNA-binding pyrrole-imidazole (Py-Im) polyamide (HIF-PA), which disrupts the HIF heterodimer from binding to its cognate DNA sequences, were also investigated. HIF-PA is cell permeable, localizes to the nuclei, and binds specific regions of DNA with an affinity comparable with that of HIFs. Most of the multiple myeloma cells were resistant to hypoxia-mediated apoptosis, and HIF-PA treatment could overcome this resistance in vitro. Using xenograft models, it was determined that HIF-PA significantly decreased tumor volume and increased hypoxic and apoptotic regions within solid tumor nodules and the growth of myeloma cells engrafted in the bone marrow. This provides a rationale for targeting the adaptive cellular hypoxic response of the O2-dependent activation of HIFα using polyamides.

Implications: Py-Im polyamides target and disrupt the adaptive hypoxic responses in multiple myeloma cells that may have clinical significance as a therapeutic strategy to treat myeloma engrafted in the bone marrow microenvironment. Mol Cancer Res; 14(3); 253–66. ©2016 AACR.
Data from SGEF Is Regulated via TWEAK/Fn14/NF-κB Signaling and Promotes Survival by Modulation of the DNA Repair Response to Temozolomide
Authors: Ensign Shannon P. Fortin , Roos Alison , Mathews Ian T. , Dhruv Harshil D. , Tuncali Serdar , Sarkaria Jann N. , Symons Marc H. , Loftus Joseph C. , Berens Michael E. , Tran Nhan L.
Published: March 2024

Abstract
Glioblastoma (GB) is the highest grade and most common form of primary adult brain tumors. Despite surgical removal followed by concomitant radiation and chemotherapy with the alkylating agent temozolomide, GB tumors develop treatment resistance and ultimately recur. Impaired response to treatment occurs rapidly, conferring a median survival of just fifteen months. Thus, it is necessary to identify the genetic and signaling mechanisms that promote tumor resistance to develop targeted therapies to combat this refractory disease. Previous observations indicated that SGEF (ARHGEF26), a RhoG-specific guanine nucleotide exchange factor (GEF), is overexpressed in GB tumors and plays a role in promoting TWEAK-Fn14–mediated glioma invasion. Here, further investigation revealed an important role for SGEF in glioma cell survival. SGEF expression is upregulated by TWEAK-Fn14 signaling via NF-κB activity while shRNA-mediated reduction of SGEF expression sensitizes glioma cells to temozolomide-induced apoptosis and suppresses colony formation following temozolomide treatment. Nuclear SGEF is activated following temozolomide exposure and complexes with the DNA damage repair (DDR) protein BRCA1. Moreover, BRCA1 phosphorylation in response to temozolomide treatment is hindered by SGEF knockdown. The role of SGEF in promoting chemotherapeutic resistance highlights a heretofore unappreciated driver, and suggests its candidacy for development of novel targeted therapeutics for temozolomide-refractory, invasive GB cells.

Implication: SGEF, as a dual process modulator of cell survival and invasion, represents a novel target for treatment refractory glioblastoma. Mol Cancer Res; 14(3); 302–12. ©2016 AACR.
Data from Increased Expression of System xc− in Glioblastoma Confers an Altered Metabolic State and Temozolomide Resistance
Authors: Polewski Monika D. , Reveron-Thornton Rosyli F. , Cherryholmes Gregory A. , Marinov Georgi K. , Cassady Kaniel , Aboody Karen S.
Published: March 2024

Abstract
Glioblastoma multiforme is the most aggressive malignant primary brain tumor in adults. Several studies have shown that glioma cells upregulate the expression of xCT (SLC7A11), the catalytic subunit of system xc−, a transporter involved in cystine import, that modulates glutathione production and glioma growth. However, the role of system xc− in regulating the sensitivity of glioma cells to chemotherapy is currently debated. Inhibiting system xc− with sulfasalazine decreased glioma growth and survival via redox modulation, and use of the chemotherapeutic agent temozolomide together with sulfasalazine had a synergistic effect on cell killing. To better understand the functional consequences of system xc− in glioma, stable SLC7A11-knockdown and -overexpressing U251 glioma cells were generated. Modulation of SLC7A11 did not alter cellar proliferation but overexpression did increase anchorage-independent cell growth. Knockdown of SLC7A11 increased basal reactive oxygen species (ROS) and decreased glutathione generation resulting in increased cell death under oxidative and genotoxic stress. Overexpression of SLC7A11 resulted in increased resistance to oxidative stress and decreased chemosensitivity to temozolomide. In addition, SLC7A11 overexpression was associated with altered cellular metabolism including increased mitochondrial biogenesis, oxidative phosphorylation, and ATP generation. These results suggest that expression of SLC7A11 in the context of glioma contributes to tumorigenesis, tumor progression, and resistance to standard chemotherapy.

Implications: SLC7A11, in addition to redox modulation, appears to be associated with increased cellular metabolism and is a mediator of temozolomide resistance in human glioma, thus making system xC− a potential therapeutic target in glioblastoma multiforme. Mol Cancer Res; 14(12); 1229–42. ©2016 AACR.
Data from A Monotonic and Prognostic Genomic Signature from Fibroblasts for Colorectal Cancer Initiation, Progression, and Metastasis
Authors: Berdiel-Acer Mireia , Cuadras Daniel , Díaz-Maroto Natalia Guillén , Sanjuan Xavier , Serrano Teresa , Berenguer Antoni , Moreno Victor , Gonçalves-Ribeiro Samuel , Salazar Ramon , Villanueva Alberto , Molleví David G.
Published: March 2024

Abstract
The differential gene expression patterns between normal colonic fibroblasts (NCF), carcinoma-associated fibroblasts from primary tumors (CAF-PT), and CAFs from hepatic metastasis (CAF-LM) are hypothesized to be useful for predicting relapse in primary tumors. A transcriptomic profile of NCF (n = 9), CAF-PT (n = 14), and CAF-LM (n = 11) was derived. Prediction Analysis of Microarrays (PAM) was used to obtain molecular details for each fibroblast class, and differentially expressed transcripts were used to classify patients according to recurrence status. A number of transcripts (n = 277) were common to all three types of fibroblasts and whose expression level was sequentially deregulated according to the transition: NCF→CAF-PT→CAF-LM. Importantly, the gene signature was able to accurately classify patients with primary tumors according to their prognosis. This capacity was exploited to obtain a refined 19-gene classifier that predicted recurrence with high accuracy in two independent datasets of patients with colorectal cancer and correlates with fibroblast migratory potential. The prognostic power of this genomic signature is strong evidence of the link between the tumor-stroma microenvironment and cancer progression. Furthermore, the 19-gene classifier was able to identify low-risk patients very accurately, which is of particular importance for stage II patients, who would benefit from the omission of chemotherapy, especially T4N0 patients, who are clinically classified as being at high risk.

Implications: A defined stromal gene expression signature predicts relapse in patients with colorectal cancer. Mol Cancer Res; 12(9); 1254–66. ©2014 AACR.
Data from DNA Polymerase Beta Germline Variant Confers Cellular Response to Cisplatin Therapy
Authors: Nemec Antonia A. , Abriola Laura , Merkel Jane S. , de Stanchina Elisa , DeVeaux Michelle , Zelterman Daniel , Glazer Peter M. , Sweasy Joann B.
Published: March 2024

Abstract
Resistance to cancer chemotherapies leads to deadly consequences, yet current research focuses only on the roles of somatically acquired mutations in this resistance. The mutational status of the germline is also likely to play a role in the way cells respond to chemotherapy. The carrier status for the POLB rs3136797 germline mutation encoding P242R DNA polymerase beta (Pol β) is associated with poor prognosis for lung cancer, specifically in response to treatment with cisplatin. Here, it is revealed that the P242R mutation is sufficient to promote resistance to cisplatin in human cells and in mouse xenografts. Mechanistically, P242R Pol β acts as a translesion polymerase and prefers to insert the correct nucleotide opposite cisplatin intrastrand cross-links, leading to the activation of the nucleotide excision repair (NER) pathway, removal of crosslinks, and resistance to cisplatin. In contrast, wild-type (WT) Pol β preferentially inserts the incorrect nucleotide initiating mismatch repair and cell death. Importantly, in a mouse xenograft model, tumors derived from lung cancer cells expressing WT Pol β displayed a slower rate of growth when treated with cisplatin, whereas tumors expressing P242R Pol β had no response to cisplatin. Pol β is critical for mediating crosstalk in response to cisplatin. The current data strongly suggest that the status of Pol β influences cellular responses to crosslinking agents and that Pol β is a promising biomarker to predict responses to specific chemotherapies. Finally, these results highlight that the genetic status of the germline is a critical factor in the response to cancer treatment.

Implications: Pol β has prognostic biomarker potential in the treatment of cancer with cisplatin and perhaps other intrastrand crosslinking agents. Mol Cancer Res; 15(3); 269–80. ©2017 AACR.
Data from Targeted Deletion and Lipidomic Analysis Identify Epithelial Cell COX-2 as a Major Driver of Chemically Induced Skin Cancer
Authors: Jiao Jing , Ishikawa Tomo-O , Dumlao Darren S. , Norris Paul C. , Magyar Clara E. , Mikulec Carol , Catapang Art , Dennis Edward A. , Fischer Susan M. , Herschman Harvey R.
Published: March 2024

Abstract
Pharmacologic and global gene deletion studies demonstrate that cyclooxygenase-2 (PTGS2/COX-2) plays a critical role in DMBA/TPA–induced skin tumor induction. Although many cell types in the tumor microenvironment express COX-2, the cell types in which COX-2 expression is required for tumor promotion are not clearly established. Here, cell type–specific Cox-2 gene deletion reveals a vital role for skin epithelial cell COX-2 expression in DMBA/TPA tumor induction. In contrast, myeloid Cox-2 gene deletion has no effect on DMBA/TPA tumorigenesis. The infrequent, small tumors that develop on mice with an epithelial cell–specific Cox-2 gene deletion have decreased proliferation and increased cell differentiation properties. Blood vessel density is reduced in tumors with an epithelial cell–specific Cox-2 gene deletion, compared with littermate control tumors, suggesting a reciprocal relationship in tumor progression between COX-2–expressing tumor epithelial cells and microenvironment endothelial cells. Lipidomics analysis of skin and tumors from DMBA/TPA–treated mice suggests that the prostaglandins PGE2 and PGF2α are likely candidates for the epithelial cell COX-2–dependent eicosanoids that mediate tumor progression. This study both illustrates the value of cell type–specific gene deletions in understanding the cellular roles of signal-generating pathways in complex microenvironments and emphasizes the benefit of a systems-based lipidomic analysis approach to identify candidate lipid mediators of biologic responses.

Implications:Cox-2 gene deletion demonstrates that intrinsic COX-2 expression in initiated keratinocytes is a principal driver of skin carcinogenesis; lipidomic analysis identifies likely prostanoid effectors. Mol Cancer Res; 12(11); 1677–88. ©2014 AACR.
Data from Distinct Effects of Adipose-Derived Stem Cells and Adipocytes on Normal and Cancer Cell Hierarchy
Authors: Anjanappa Manjushree , Burnett Riesa , Zieger Michael A. , Merfeld-Clauss Stephanie , Wooden William , March Keith , Tholpady Sunil , Nakshatri Harikrishna
Published: March 2024

Abstract
Adipose-derived stem cells (ASC) have received considerable attention in oncology because of the known direct link between obesity and cancer as well as the use of ASCs in reconstructive surgery after tumor ablation. Previous studies have documented how cancer cells commandeer ASCs to support their survival by altering extracellular matrix composition and stiffness, migration, and metastasis. This study focused on delineating the effects of ASCs and adipocytes on the self-renewal of stem/progenitor cells and hierarchy of breast epithelial cells. The immortalized breast epithelial cell line MCF10A, ductal carcinoma in situ (DCIS) cell lines MCF10DCIS.com and SUM225, and MCF10A-overexpressing SRC oncogene were examined using a mammosphere assay and flow cytometry for the effects of ASCs on their self-renewal and stem-luminal progenitor-differentiated cell surface marker profiles. Interestingly, ASCs promoted the self-renewal of all cell types except SUM225. ASC coculture or treatment with ASC conditioned media altered the number of CD49fhigh/EpCAMlow basal/stem-like and CD49fmedium/EpCAMmedium luminal progenitor cells. Among multiple factors secreted by ASCs, IFNγ and hepatocyte growth factor (HGF) displayed unique actions on epithelial cell hierarchy. IFNγ increased stem/progenitor-like cells while simultaneously reducing the size of mammospheres, whereas HGF increased the size of mammospheres with an accompanying increase in luminal progenitor cells. ASCs expressed higher levels of HGF, whereas adipocytes expressed higher levels of IFNγ. As luminal progenitor cells are believed to be prone for transformation, IFNγ and HGF expression status of ASCs may influence susceptibility for developing breast cancer as well as on outcomes of autologous fat transplantation on residual/dormant tumor cells.

Implications: This study suggests that the ratio of ASCs to adipocytes influences cancer cell hierarchy, which may impact incidence and progression. Mol Cancer Res; 14(7); 660–71. ©2016 AACR.
Data from Autotaxin and LPA1 and LPA5 Receptors Exert Disparate Functions in Tumor Cells versus the Host Tissue Microenvironment in Melanoma Invasion and Metastasis
Authors: Lee Sue-Chin , Fujiwara Yuko , Liu Jianxiong , Yue Junming , Shimizu Yoshibumi , Norman Derek D. , Wang Yaohong , Tsukahara Ryoko , Szabo Erzsebet , Patil Renukadevi , Banerjee Souvik , Miller Duane D. , Balazs Louisa , Ghosh Manik C. , Waters Christopher M. , Oravecz Tamas , Tigyi Gabor J.
Published: March 2024

Abstract
Autotaxin (ENPP2/ATX) and lysophosphatidic acid (LPA) receptors represent two key players in regulating cancer progression. The present study sought to understand the mechanistic role of LPA G protein–coupled receptors (GPCR), not only in the tumor cells but also in stromal cells of the tumor microenvironment. B16F10 melanoma cells predominantly express LPA5 and LPA2 receptors but lack LPA1. LPA dose dependently inhibited invasion of cells across a Matrigel layer. RNAi-mediated knockdown of LPA5 relieved the inhibitory effect of LPA on invasion without affecting basal invasion. This suggests that LPA5 exerts an anti-invasive action in melanoma cells in response to LPA. In addition, both siRNA-mediated knockdown and pharmacologic inhibition of LPA2 reduced the basal rate invasion. Unexpectedly, when probing the role of this GPCR in host tissues, it was found that the incidence of melanoma-derived lung metastasis was greatly reduced in LPA5 knockout (KO) mice compared with wild-type (WT) mice. LPA1-KO but not LPA2-KO mice also showed diminished melanoma-derived lung metastasis, suggesting that host LPA1 and LPA5 receptors play critical roles in the seeding of metastasis. The decrease in tumor cell residence in the lungs of LPA1-KO and LPA5-KO animals was apparent 24 hours after injection. However, KO of LPA1, LPA2, or LPA5 did not affect the subcutaneous growth of melanoma tumors.

Implications: These findings suggest that tumor and stromal LPA receptors, in particular LPA1 and LPA5, play different roles in invasion and the seeding of metastasis. Mol Cancer Res; 13(1); 174–85. ©2014 AACR.
Data from Cyclosporin A Promotes Tumor Angiogenesis in a Calcineurin-Independent Manner by Increasing Mitochondrial Reactive Oxygen Species
Authors: Zhou Alice Yao , Ryeom Sandra
Published: March 2024

Abstract
The widely used immunosuppressant cyclosporin A, a potent calcineurin inhibitor, significantly increases the incidence of cancer in organ transplant patients. Calcineurin signaling is an important mediator of VEGF signaling in endothelial cells. Negative regulation of calcineurin by its endogenous inhibitor, Down Syndrome Candidate Region-1 (DSCR1), suppresses tumor growth and angiogenesis, in contrast to the effect observed after long-term cyclosporin A treatment. Despite the significance of calcineurin signaling in endothelial cells, the consequences of cyclosporin A on tumor angiogenesis have not been investigated. Using an in vivo model of skin carcinogenesis, prolonged treatment with cyclosporin A promoted tumor growth and angiogenesis. The addition of cyclosporin A to endothelial cells in vitro increased proliferation and migration in a calcineurin-independent manner and is associated with increased mitochondrial reactive oxygen species (ROS). Co-treatment with antioxidants significantly abrogated cyclosporin A–induced endothelial cell activation. Furthermore, mice treated with antioxidants were protected against cyclosporin A–mediated tumor progression. Taken together, these findings suggest that cyclosporin A affects endothelial cells in a calcineurin-independent manner to potentiate tumor growth by promoting tumor angiogenesis through increasing mitochondrial ROS production. This work identifies a previously undescribed mechanism underlying a significantly adverse off-target effect of cyclosporin A and suggests that co-treatment with antioxidants would inhibit the tumor-promoting effects of cyclosporin A.

Implications: Targeting the proangiogenic effects of cyclosporin A may be useful in the management of transplant-associated cancers. Mol Cancer Res; 12(11); 1663–76. ©2014 AACR.
Data from Chemoradiotherapy Resistance in Colorectal Cancer Cells is Mediated by Wnt/β-catenin Signaling
Authors: Emons Georg , Spitzner Melanie , Reineke Sebastian , Möller Janneke , Auslander Noam , Kramer Frank , Hu Yue , Beissbarth Tim , Wolff Hendrik A. , Rave-Fränk Margret , Heßmann Elisabeth , Gaedcke Jochen , Ghadimi B. Michael , Johnsen Steven A. , Ried Thomas , Grade Marian
Published: March 2024

Abstract
Activation of Wnt/β-catenin signaling plays a central role in the development and progression of colorectal cancer. The Wnt-transcription factor, TCF7L2, is overexpressed in primary rectal cancers that are resistant to chemoradiotherapy and TCF7L2 mediates resistance to chemoradiotherapy. However, it is unclear whether the resistance is mediated by a TCF7L2 inherent mechanism or Wnt/β-catenin signaling in general. Here, inhibition of β-catenin by siRNAs or a small-molecule inhibitor (XAV-939) resulted in sensitization of colorectal cancer cells to chemoradiotherapy. To investigate the potential role of Wnt/β-catenin signaling in controlling therapeutic responsiveness, nontumorigenic RPE-1 cells were stimulated with Wnt-3a, a physiologic ligand of Frizzled receptors, which increased resistance to chemoradiotherapy. This effect could be recapitulated by overexpression of a degradation-resistant mutant of β-catenin (S33Y), also boosting resistance of RPE-1 cells to chemoradiotherapy, which was, conversely, abrogated by siRNA-mediated silencing of β-catenin. Consistent with these findings, higher expression levels of active β-catenin were observed as well as increased TCF/LEF reporter activity in SW1463 cells that evolved radiation resistance due to repeated radiation treatment. Global gene expression profiling identified several altered pathways, including PPAR signaling and other metabolic pathways, associated with cellular response to radiation. In summary, aberrant activation of Wnt/β-catenin signaling not only regulates the development and progression of colorectal cancer, but also mediates resistance of rectal cancers to chemoradiotherapy.

Implications: Targeting Wnt/β-catenin signaling or one of the downstream pathways represents a promising strategy to increase response to chemoradiotherapy. Mol Cancer Res; 15(11); 1481–90. ©2017 AACR.
Data from Depleting Tumor-NQO1 Potentiates Anoikis and Inhibits Growth of NSCLC
Authors: Madajewski Brian , Boatman Michael A. , Chakrabarti Gaurab , Boothman David A. , Bey Erik A.
Published: March 2024

Abstract
The fundamental role that NAD(P)H/quinone oxidoreductase 1 (NQO1) plays, in normal cells, as a cytoprotective enzyme guarding against stress induced by reactive oxygen species (ROS) is well documented. However, what is not known is whether the observed overexpression of NQO1 in neoplastic cells contributes to their survival. The current study discovered that depleting NQO1 expression in A549 and H292 lung adenocarcinoma cells caused an increase in ROS formation, inhibited anchorage-independent growth, increased anoikis sensitization, and decreased three-dimensional tumor spheroid invasion. These in vivo data further implicate tumor-NQO1 expression in a protumor survival role, because its depletion suppressed cell proliferation and decreased lung tumor xenograft growth. Finally, these data reveal an exploitable link between tumor-NQO1 expression and the survival of lung tumors because NQO1 depletion significantly decreased the percentage of ALDH(high) cancer cells within the tumor population.

Implications: Loss of tumor-NQO1 expression inhibits tumor growth and suggests that novel therapeutics directed at tumor-NQO1 may have clinical benefit. Mol Cancer Res; 14(1); 14–25. ©2015 AACR.
Data from SMAD4 Suppresses AURKA-Induced Metastatic Phenotypes via Degradation of AURKA in a TGFβ-Independent Manner
Authors: Jia Lina , Lee Hun Seok , Wu Chun Fu , Kundu Juthika , Park Sang Gyu , Kim Ryong Nam , Wang Li-Hui , Erkin Özgür Cem , Choi Jong-Sun , Chae Seoung Wan , Yang Ho Bin , Choi Yoon-La , Shin Young Kee
Published: March 2024

Abstract
SMAD4 has been suggested to inhibit the activity of the WNT/β-catenin signaling pathway in cancer. However, the mechanism by which SMAD4 antagonizes WNT/β-catenin signaling in cancer remains largely unknown. Aurora A kinase (AURKA), which is frequently overexpressed in cancer, increases the transcriptional activity of β-catenin/T-cell factor (TCF) complex by stabilizing β-catenin through the inhibition of GSK-3β. Here, SMAD4 modulated AURKA in a TGFβ-independent manner. Overexpression of SMAD4 significantly suppressed AURKA function, including colony formation, migration, and invasion of cell lines. In addition, SMAD4 bound to AURKA induced degradation of AURKA by the proteasome. A luciferase activity assay revealed that the transcriptional activity of the β-catenin/TCF complex was elevated by AURKA, but decreased by SMAD4 overexpression. Moreover, target gene analysis showed that SMAD4 abrogated the AURKA-mediated increase of β-catenin target genes. However, this inhibitory effect of SMAD4 was abolished by overexpression of AURKA or silencing of AURKA in SMAD4-overexpressed cells. Meanwhile, the SMAD4-mediated repression of AURKA and β-catenin was independent of TGFβ signaling because blockage of TGFβR1 or restoration of TGFβ signaling did not prevent suppression of AURKA and β-catenin signaling by SMAD4. These results indicate that the tumor-suppressive function of SMAD4 is mediated by downregulation of β-catenin transcriptional activity via AURKA degradation in a TGFβ-independent manner.

Implications: SMAD4 interacts with AURKA and antagonizes its tumor-promoting potential, thus demonstrating a novel mechanism of tumor suppression. Mol Cancer Res; 12(12); 1779–95. ©2014 AACR.
Data from Abituzumab Targeting of αV-Class Integrins Inhibits Prostate Cancer Progression
Authors: Jiang Yuan , Dai Jinlu , Yao Zhi , Shelley Greg , Keller Evan T.
Published: March 2024

Abstract
Integrins that contain an integrin αV subunit contribute to multiple functions that promote cancer progression. The goal of this study was to determine whether abituzumab (DI17E6, EMD 525797), a humanized monoclonal antibody (mAb) against integrin αV impacts, prostate cancer progression. To evaluate this, prostate cancer cells were treated with DI17E6 and its effects on proliferation, apoptosis, cell-cycle, adhesion, detachment, migration, invasion and phosphorylation of downstream targets, including FAK, Akt, and ERK, were determined. DI17E6 promoted detachment and inhibited adhesion of prostate cancer cells to several extracellular matrix (ECM) proteins and cells found in the bone microenvironment but had no impact on cell viability, cell-cycle, and caspase-3/7 activity. DI17E6 inhibited migration and invasion of prostate cancer cells. In addition, DI7E6 decreased phosphorylation of FAK, Akt, and ERK. These results indicate that inhibition of integrin αV with DI17E6 inhibits several prometastatic phenotypes of prostate cancer cells and therefore provide a rationale for further evaluation of DI17E6 for diminishing prostate cancer progression.

Implications: This work identifies that therapeutic targeting of integrins containing an αV integrin unit inhibits cancer progression and thus may be of clinical benefit. Mol Cancer Res; 15(7); 875–83. ©2017 AACR.
Data from Cyclin A2 and CDK2 as Novel Targets of Aspirin and Salicylic Acid: A Potential Role in Cancer Prevention
Authors: Dachineni Rakesh , Ai Guoqiang , Kumar D. Ramesh , Sadhu Satya S. , Tummala Hemachand , Bhat G. Jayarama
Published: March 2024

Abstract
Data emerging from the past 10 years have consolidated the rationale for investigating the use of aspirin as a chemopreventive agent; however, the mechanisms leading to its anticancer effects are still being elucidated. We hypothesized that aspirin's chemopreventive actions may involve cell-cycle regulation through modulation of the levels or activity of cyclin A2/cyclin-dependent kinase-2 (CDK2). In this study, HT-29 and other diverse panel of cancer cells were used to demonstrate that both aspirin and its primary metabolite, salicylic acid, decreased cyclin A2 (CCNA2) and CDK2 protein and mRNA levels. The downregulatory effect of either drugs on cyclin A2 levels was prevented by pretreatment with lactacystin, an inhibitor of proteasomes, suggesting the involvement of 26S proteasomes. In-vitro kinase assays showed that lysates from cells treated with salicylic acid had lower levels of CDK2 activity. Importantly, three independent experiments revealed that salicylic acid directly binds to CDK2. First, inclusion of salicylic acid in naïve cell lysates, or in recombinant CDK2 preparations, increased the ability of the anti-CDK2 antibody to immunoprecipitate CDK2, suggesting that salicylic acid may directly bind and alter its conformation. Second, in 8-anilino-1-naphthalene-sulfonate (ANS)-CDK2 fluorescence assays, preincubation of CDK2 with salicylic acid dose-dependently quenched the fluorescence due to ANS. Third, computational analysis using molecular docking studies identified Asp145 and Lys33 as the potential sites of salicylic acid interactions with CDK2. These results demonstrate that aspirin and salicylic acid downregulate cyclin A2/CDK2 proteins in multiple cancer cell lines, suggesting a novel target and mechanism of action in chemoprevention.

Implications: Biochemical and structural studies indicate that the antiproliferative actions of aspirin are mediated through cyclin A2/CDK2. Mol Cancer Res; 14(3); 241–52. ©2015 AACR.
Data from Novel Insights into Gastric Cancer: Methylation of R-spondins and Regulation of LGR5 by SP1
Authors: Wilhelm Franziska , Simon Eva , Böger Christine , Behrens Hans-Michael , Krüger Sandra , Röcken Christoph
Published: March 2024

Abstract
Recently, it was shown that leucine-rich repeat-containing receptor 5 (LGR5)–expressing stem cells are the cellular origin of intestinal-type gastric cancer. The aim of our study was to uncover regulatory mechanisms of LGR5 expression in gastric mucosa and their implications for cancer development. Reporter assays identified an LGR5 promoter fragment, which is highly relevant for active LGR5 expression. Chromatin immunoprecipitation verified that SP1 is bound within this region, and reporter activity increased in SP1 transfected cells. Subsequently, the expression of R-spondins (RSPO1 and RSPO2), ligands of LGR5, was explored in neoplastic and nonneoplastic gastric tissue and gastric cancer cell lines. Using IHC, distinct spatial expression patterns of LGR5, RSPO1, and RSPO2 were found in nonneoplastic stomach mucosa and gastric cancer. RSPO expression was lower in gastric cancer compared with nonneoplastic mucosa on both the transcriptional (P = 0.003 for RSPO1 and P = 0.000 for RSPO2; n = 50) and the translational level. Methylation-specific PCR showed higher methylation levels of RSPO1/2 and reexpression of RSPOs in the gastric cancer cell lines MKN45 and MKN74 were induced by demethylating 5-aza-C treatment. Finally, expression patterns of LGR5 and RSPO were similar in gastric cancer.

Implications: This report identifies a regulatory mechanism of LGR5 expression in gastric carcinogenesis, with SP1 as an important component of the transcriptional complex and LGR5 activity, which is modulated by its ligands RSPO1 and RSPO2, whose expression is modulated by methylation.

Visual Overview: http://mcr.aacrjournals.org/content/15/6/776/F1.large.jpg. Mol Cancer Res; 15(6); 776–85. ©2017 AACR.
Data from DNA Damage-Binding Complex Recruits HDAC1 to Repress Bcl-2 Transcription in Human Ovarian Cancer Cells
Authors: Zhao Ran , Han Chunhua , Eisenhauer Eric , Kroger John , Zhao Weiqiang , Yu Jianhua , Selvendiran Karuppaiyah , Liu Xingluo , Wani Altaf A. , Wang Qi-En
Published: March 2024

Abstract
Elevated expression of the antiapoptotic factor Bcl-2 is believed to be one of the contributing factors to an increased relapse rate associated with multiple cisplatin-resistant cancers. DNA damage-binding protein complex subunit 2 (DDB2) has recently been revealed to play an important role in sensitizing human ovarian cancer cells to cisplatin-induced apoptosis through the downregulation of Bcl-2, but the underlying molecular mechanism remains poorly defined. Here, it is report that DDB2 functions as a transcriptional repressor for Bcl-2 in combination with DDB1. Quantitative ChIP and EMSA analysis revealed that DDB2 binds to a specific cis-acting element at the 5′-end of Bcl-2 P1 promoter. Overexpression of DDB2 resulted in marked losses of histone H3K9,14 acetylation along the Bcl-2 promoter and enhancer regions, concomitant with a local enrichment of HDAC1 to the Bcl-2 P1 core promoter in ovarian cancer cells. Coimmunoprecipitation and in vitro binding analyses identified a physical interaction between DDB1 and HDAC1, whereas downregulation of HDAC1 significantly enhanced Bcl-2 promoter activity. Finally, in comparison with wild-type DDB2, mutated DDB2, which is unable to repress Bcl-2 transcription, mediates a compromised apoptosis upon cisplatin treatment. Taken together, these data support a model wherein DDB1 and DDB2 cooperate to repress Bcl-2 transcription. DDB2 recognizes and binds to the Bcl-2 P1 promoter, and HDAC1 is recruited through the DDB1 subunit associated with DDB2 to deacetylate histone H3K9,14 across Bcl-2 regulatory regions, resulting in suppressed Bcl-2 transcription.

Implications: Increasing the expression of DDB complex may provide a molecular strategy for cancer therapy. Mol Cancer Res; 12(3); 370–80. ©2013 AACR.
Data from Let-7 Status Is Crucial for PARP1 Expression in HER2-Overexpressing Breast Tumors
Authors: Wielgos Monica E. , Rajbhandari Rajani , Cooper Tiffiny S. , Wei Shi , Nozell Susan , Yang Eddy S.
Published: March 2024

Abstract
HER2+ breast tumors have been shown to express elevated levels of PARP1 protein. Yet, the mechanism by which PARP1 is upregulated in HER2+ breast cancer is unknown. Here, knockdown of HER2 (ERBB2) in HER2+ breast cancer cells resulted in a reduction in PARP1 protein. Conversely, ectopic overexpression of HER2 in a non-HER2–overexpressing cell line resulted in increased PARP1 protein levels. Alterations in HER2 expression had no significant effect on PARP1 transcript levels. Instead, HER2 mRNA status was inversely correlated with let-7a miRNA levels in breast cancer cells. Ectopic expression of let-7a miRNA resulted in downregulation of PARP1 protein, whereas expression of the let-7a anti-miRNA increased PARP1 protein. Furthermore, luciferase assays demonstrate that let-7a regulates PARP1 via its 3′UTR. Importantly, let-7a was significantly lower in human HER2+ breast tumors compared with HER2− breast tumors and inversely correlated with PARP1 protein levels. Finally, HER2+ breast cancer cells exhibited similar cytotoxicity to ectopic let-7a expression as the PARP inhibitor veliparib (ABT-888). Collectively, these results reveal that increased PARP1 expression in HER2+ breast cancers is regulated by the let-7a miRNA, and that let-7a is a potential strategy to suppress PARP1 activity.

Implications: This study reports the novel findings that HER2 increases PARP1 protein via suppression of the let-7a miRNA, which regulates the PARP1 3′-UTR. Moreover, HER2 status correlates with high PARP1 and low let-7a in breast cancer clinical specimens. Mol Cancer Res; 15(3); 340–7. ©2016 AACR.
Data from VEGFR-1 Pseudogene Expression and Regulatory Function in Human Colorectal Cancer Cells
Authors: Ye Xiangcang , Fan Fan , Bhattacharya Rajat , Bellister Seth , Boulbes Delphine R. , Wang Rui , Xia Ling , Ivan Cristina , Zheng Xiaofeng , Calin George A. , Wang Jing , Lu Xiongbin , Ellis Lee M.
Published: March 2024

Abstract
A large number of pseudogenes have been found to be transcribed in human cancers. However, only a few pseudogenes are functionally characterized. Here, we identified a transcribed pseudogene of VEGFR1, or fms-related tyrosine kinase 1 (FLT1), in human colorectal cancer cells. Interestingly, this pseudogene (designated as FLT1P1) was found to be transcribed bidirectionally and functionally modulated cognate VEGFR1 protein expression in the cells. Mechanistically, expression of FLT1P1 antisense transcript not only inhibited the VEGFR1 expression, but also inhibited non-cognate VEGF-A expression through interaction with miR-520a. Perturbation of FLT1P1 expression by RNA interference (RNAi) markedly inhibited tumor cell proliferation and xenograft tumor growth. This study identifies FLT1P1 antisense as a critical regulator of VEGFR1 and VEGF-A expression in colorectal cancer cells, and highlights its role in regulation of the pathogenesis of colorectal cancer.

Implications: The VEGFR1 pseudogene, FLT1P1, is a novel and functional regulator of VEGF signaling and its targeting could be an alternative strategy to modulate its cognate/target gene expression and downstream activity in cancer. Mol Cancer Res; 13(9); 1274–82. ©2015 AACR.
Data from ERβ Regulates NSCLC Phenotypes by Controlling Oncogenic RAS Signaling
Authors: Nikolos Fotis , Thomas Christoforos , Rajapaksa Gayani , Bado Igor , Gustafsson Jan-Åke
Published: March 2024

Abstract
Non–small cell lung cancer (NSCLC) is the leading cause of cancer-related deaths worldwide. In addition to the aberrant growth factor signaling, dysregulation of other pathways, such as those mediated by estrogens and their receptors, has been linked to NSCLC initiation and progression. Although the expression of wild-type estrogen receptor β (ERβ1) has been associated with prolonged disease-free survival in patients with NSCLC, the molecular mechanism that accounts for this correlation is unknown. Here, upregulation of ERβ1 reduced proliferation and enhanced apoptosis in the context of mutant RAS. ERβ1 was found to induce apoptosis by stimulating the intrinsic apoptotic pathway that involves BIM, a Bcl-2 proapoptotic family member that is regulated by the extracellular signal–regulated kinase (ERK). Downregulation of EGFR and inactivation of RAS and the downstream components ERK1/2 were found to be involved in the ERβ1-induced apoptosis. Manipulation of EGFR and RAS expression and activity in ERβ1-expressing cells revealed the central role of oncogenic RAS inhibition in the ERβ1-mediated proapoptotic phenotype and EGFR regulation. These results demonstrate that ERβ1 decreases the survival of NSCLC cells by regulating oncogenic RAS signaling.

Implications: The ability of ERβ1 to regulate the oncogenic functions of RAS suggests its importance in the biology of NSCLC and its clinical management. Mol Cancer Res; 12(6); 843–54. ©2014 AACR.
Data from Targeting AR Variant–Coactivator Interactions to Exploit Prostate Cancer Vulnerabilities
Authors: Magani Fiorella , Peacock Stephanie O. , Rice Meghan A. , Martinez Maria J. , Greene Ann M. , Magani Pablo S. , Lyles Rolando , Weitz Jonathan R. , Burnstein Kerry L.
Published: March 2024

Abstract
Castration-resistant prostate cancer (CRPC) progresses rapidly and is incurable. Constitutively active androgen receptor splice variants (AR-Vs) represent a well-established mechanism of therapeutic resistance and disease progression. These variants lack the AR ligand-binding domain and, as such, are not inhibited by androgen deprivation therapy (ADT), which is the standard systemic approach for advanced prostate cancer. Signaling by AR-Vs, including the clinically relevant AR-V7, is augmented by Vav3, an established AR coactivator in CRPC. Using mutational and biochemical studies, we demonstrated that the Vav3 Diffuse B-cell lymphoma homology (DH) domain interacted with the N-terminal region of AR-V7 (and full length AR). Expression of the Vav3 DH domain disrupted Vav3 interaction with and enhancement of AR-V7 activity. The Vav3 DH domain also disrupted AR-V7 interaction with other AR coactivators: Src1 and Vav2, which are overexpressed in PC. This Vav3 domain was used in proof-of-concept studies to evaluate the effects of disrupting the interaction between AR-V7 and its coactivators on CRPC cells. This disruption decreased CRPC cell proliferation and anchorage-independent growth, caused increased apoptosis, decreased migration, and resulted in the acquisition of morphological changes associated with a less aggressive phenotype. While disrupting the interaction between FL-AR and its coactivators decreased N-C terminal interaction, disrupting the interaction of AR-V7 with its coactivators decreased AR-V7 nuclear levels.

Implications: This study demonstrates the potential therapeutic utility of inhibiting constitutively active AR-V signaling by disrupting coactivator binding. Such an approach is significant, as AR-Vs are emerging as important drivers of CRPC that are particularly recalcitrant to current therapies. Mol Cancer Res; 15(11); 1469–80. ©2017 AACR.
Data from EWS/FLI is a Master Regulator of Metabolic Reprogramming in Ewing Sarcoma
Authors: Tanner Jason M. , Bensard Claire , Wei Peng , Krah Nathan M. , Schell John C. , Gardiner Jamie , Schiffman Joshua , Lessnick Stephen L. , Rutter Jared
Published: March 2024

Abstract
Ewing sarcoma is a bone malignancy driven by a translocation event resulting in the fusion protein EWS/FLI1 (EF). EF functions as an aberrant and oncogenic transcription factor that misregulates the expression of thousands of genes. Previous work has focused principally on determining important transcriptional targets of EF, as well as characterizing important regulatory partnerships in EF-dependent transcriptional programs. Less is known, however, about EF-dependent metabolic changes or their role in Ewing sarcoma biology. Therefore, the metabolic effects of silencing EF in Ewing sarcoma cells were determined. Metabolomic analyses revealed distinct separation of metabolic profiles in EF-knockdown versus control-knockdown cells. Mitochondrial stress tests demonstrated that knockdown of EF increased respiratory as well as glycolytic functions. Enzymes and metabolites in several metabolic pathways were altered, including de novo serine synthesis and elements of one-carbon metabolism. Furthermore, phosphoglycerate dehydrogenase (PHGDH) was found to be highly expressed in Ewing sarcoma and correlated with worse patient survival. PHGDH knockdown or pharmacologic inhibition in vitro caused impaired proliferation and cell death. Interestingly, PHGDH modulation also led to elevated histone expression and methylation. These studies demonstrate that the translocation-derived fusion protein EF is a master regulator of metabolic reprogramming in Ewing sarcoma, diverting metabolites toward biosynthesis. As such, these data suggest that the metabolic aberrations induced by EF are important contributors to the oncogenic biology of these tumors.

Implications: This previously unexplored role of EWS/FLI1–driven metabolic changes expands the understanding of Ewing sarcoma biology, and has potential to significantly inform development of therapeutic strategies. Mol Cancer Res; 15(11); 1517–30. ©2017 AACR.
Data from Predictive Outcomes for HER2-enriched Cancer Using Growth and Metastasis Signatures Driven By SPARC
Authors: Güttlein Leandro N. , Benedetti Lorena G. , Fresno Cristóbal , Spallanzani Raúl G. , Mansilla Sabrina F. , Rotondaro Cecilia , Raffo Iraolagoitia Ximena L. , Salvatierra Edgardo , Bravo Alicia I. , Fernández Elmer A. , Gottifredi Vanesa , Zwirner Norberto W. , Llera Andrea S. , Podhajcer Osvaldo L.
Published: March 2024

Abstract
Understanding the mechanism of metastatic dissemination is crucial for the rational design of novel therapeutics. The secreted protein acidic and rich in cysteine (SPARC) is a matricellular glycoprotein which has been extensively associated with human breast cancer aggressiveness although the underlying mechanisms are still unclear. Here, shRNA-mediated SPARC knockdown greatly reduced primary tumor growth and completely abolished lung colonization of murine 4T1 and LM3 breast malignant cells implanted in syngeneic BALB/c mice. A comprehensive study including global transcriptomic analysis followed by biological validations confirmed that SPARC induces primary tumor growth by enhancing cell cycle and by promoting a COX-2–mediated expansion of myeloid-derived suppressor cells (MDSC). The role of SPARC in metastasis involved a COX-2–independent enhancement of cell disengagement from the primary tumor and adherence to the lungs that fostered metastasis implantation. Interestingly, SPARC-driven gene expression signatures obtained from these murine models predicted the clinical outcome of patients with HER2-enriched breast cancer subtypes. In total, the results reveal that SPARC and its downstream effectors are attractive targets for antimetastatic therapies in breast cancer.

Implications: These findings shed light on the prometastatic role of SPARC, a key protein expressed by breast cancer cells and surrounding stroma, with important consequences for disease outcome. Mol Cancer Res; 15(3); 304–16. ©2016 AACR.