bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Shmt1 Heterozygosity Impairs Folate-Dependent Thymidylate Synthesis Capacity and Modifies Risk of Apcmin-Mediated Intestinal Cancer Risk
Authors: MacFarlane Amanda J. , Perry Cheryll A. , McEntee Michael F. , Lin David M. , Stover Patrick J.
Published: March 2024

Abstract
Folate-mediated one-carbon metabolism is required for the de novo synthesis of purines, thymidylate, and S-adenosylmethionine, the primary cellular methyl donor. Impairments in folate metabolism diminish cellular methylation potential and genome stability, which are risk factors for colorectal cancer (CRC). Cytoplasmic serine hydroxymethyltransferase (SHMT1) regulates the partitioning of folate-activated one-carbons between thymidylate and S-adenosylmethionine biosynthesis. Therefore, changes in SHMT1 expression enable the determination of the specific contributions made by thymidylate and S-adenosylmethionine biosynthesis to CRC risk. Shmt1 hemizygosity was associated with a decreased capacity for thymidylate synthesis due to downregulation of enzymes in its biosynthetic pathway, namely thymidylate synthase and cytoplasmic thymidine kinase. Significant Shmt1-dependent changes to methylation capacity, gene expression, and purine synthesis were not observed. Shmt1 hemizygosity was associated with increased risk for intestinal cancer in Apcmin/+ mice through a gene-by-diet interaction, indicating that the capacity for thymidylate synthesis modifies susceptibility to intestinal cancer in Apcmin/+ mice. Cancer Res; 71(6); 2098–107. ©2011 AACR.
Data from The EphB6 Receptor Cooperates with c-Cbl to Regulate the Behavior of Breast Cancer Cells
Authors: Truitt Luke , Freywald Tanya , DeCoteau John , Sharfe Nigel , Freywald Andrew
Published: March 2024

Abstract
Cancer invasiveness plays a major role in the mortality of patients with solid tumors, and deregulated cell adhesion and migration are suspected to drive invasive behavior. Since Eph receptor tyrosine kinases control both cell attachment and migration, they may act to define the level of cancer invasiveness. EphB6 is an unusual Eph receptor, lacking catalytic capacity due to alterations in its kinase domain. Interestingly, increased metastatic activity is associated with reduced EphB6 receptor expression in several tumor types, including breast cancer. This emphasizes the potential of EphB6 to act as a suppressor of cancer aggressiveness; however, the mechanism of its action is not well understood. We show that restoration of EphB6 expression in invasive breast cancer cells supports actin-dependent spreading and attachment and blocks invasiveness. EphB6 stimulation induces its tyrosine phosphorylation, which is crucial for its function and is mediated by the EphB4 receptor. This is accompanied by EphB6–c-Cbl interaction and phosphorylation of c-Cbl partner, the Abl kinase. Cbl silencing suppresses Abl phosphorylation, cell adhesion, and morphologic changes and blocks the ability of EphB6 to inhibit invasiveness, confirming its importance for EphB6 activity. Despite its crucial role in EphB6 responses, EphB4 also acts in an EphB6-independent manner to enhance invasive activity, suggesting that cancer invasiveness may be defined by the balance in the EphB6-EphB4 system. Overall, our observations suggest a new role for EphB6 in suppressing cancer invasiveness through c-Cbl–dependent signaling, morphologic changes, and cell attachment and indicate that EphB6 may represent a useful prognostic marker and a promising target for therapeutic approaches. Cancer Res; 70(3); 1141–53
Data from p53 Regulates the Ras Circuit to Inhibit the Expression of a Cancer-Related Gene Signature by Various Molecular Pathways
Authors: Buganim Yosef , Solomon Hilla , Rais Yoach , Kistner Daria , Nachmany Ido , Brait Mariana , Madar Shalom , Goldstein Ido , Kalo Eyal , Adam Nitzan , Gordin Maya , Rivlin Noa , Kogan Ira , Brosh Ran , Sefadia-Elad Galit , Goldfinger Naomi , Sidransky David , Kloog Yoel , Rotter Varda
Published: March 2024

Abstract
In this study, we focus on the analysis of a previously identified cancer-related gene signature (CGS) that underlies the cross talk between the p53 tumor suppressor and Ras oncogene. CGS consists of a large number of known Ras downstream target genes that were synergistically upregulated by wild-type p53 loss and oncogenic H-RasG12V expression. Here we show that CGS expression strongly correlates with malignancy. In an attempt to elucidate the molecular mechanisms underling the cooperation between p53 loss and oncogenic H-RasG12V, we identified distinguished pathways that may account for the regulation of the expression of the CGS. By knocking-down p53 or by expressing mutant p53, we revealed that p53 exerts its negative effect by at least two mechanisms mediated by its targets B-cell translocation gene 2 (BTG2) and activating transcription factor 3 (ATF3). Whereas BTG2 binds H-RasG12V and represses its activity by reducing its GTP loading state, which in turn causes a reduction in CGS expression, ATF3 binds directly to the CGS promoters following p53 stabilization and represses their expression. This study further elucidates the molecular loop between p53 and Ras in the transformation process. Cancer Res; 70(6); 2274–84
Data from Antibody-Maytansinoid Conjugates Designed to Bypass Multidrug Resistance
Authors: Kovtun Yelena V. , Audette Charlene A. , Mayo Michele F. , Jones Gregory E. , Doherty Heather , Maloney Erin K. , Erickson Hans K. , Sun Xiuxia , Wilhelm Sharon , Ab Olga , Lai Katharine C. , Widdison Wayne C. , Kellogg Brenda , Johnson Holly , Pinkas Jan , Lutz Robert J. , Singh Rajeeva , Goldmacher Victor S. , Chari Ravi V.J.
Published: March 2024

Abstract
Conjugation of cytotoxic compounds to antibodies that bind to cancer-specific antigens makes these drugs selective in killing cancer cells. However, many of the compounds used in such antibody-drug conjugates (ADC) are substrates for the multidrug transporter MDR1. To evade the MDR1-mediated resistance, we conjugated the highly cytotoxic maytansinoid DM1 to antibodies via the maleimidyl-based hydrophilic linker PEG4Mal. Following uptake into target cells, conjugates made with the PEG4Mal linker were processed to a cytotoxic metabolite that was retained by MDR1-expressing cells better than a metabolite of similar conjugates prepared with the nonpolar linker N-succinimidyl-4-(maleimidomethyl)cyclohexane-1-carboxylate (SMCC). In accord, PEG4Mal-linked conjugates were more potent in killing MDR1-expressing cells in culture. In addition, PEG4Mal-linked conjugates were markedly more effective in eradicating MDR1-expressing human xenograft tumors than SMCC-linked conjugates while being tolerated similarly, thus showing an improved therapeutic index. This study points the way to the development of ADCs that bypass multidrug resistance. Cancer Res; 70(6); 2528–37
Data from Local Radiation Therapy Inhibits Tumor Growth through the Generation of Tumor-Specific CTL: Its Potentiation by Combination with Th1 Cell Therapy
Authors: Takeshima Tsuguhide , Chamoto Kenji , Wakita Daiko , Ohkuri Takayuki , Togashi Yuji , Shirato Hiroki , Kitamura Hidemitsu , Nishimura Takashi
Published: March 2024

Abstract
Radiation therapy is one of the primary treatment modalities for cancer along with chemotherapy and surgical therapy. The main mechanism of the tumor reduction after irradiation has been considered to be damage to the tumor DNA. However, we found that tumor-specific CTL, which were induced in the draining lymph nodes (DLN) and tumor tissue of tumor-bearing mice, play a crucial role in the inhibition of tumor growth by radiation. Indeed, the therapeutic effect of irradiation was almost completely abolished in tumor-bearing mice by depleting CD8+ T cells through anti-CD8 monoclonal antibody administration. In mice whose DLN were surgically ablated or genetically defective (Aly/Aly mice), the generation of tetramer+ tumor-specific CTL at the tumor site was greatly reduced in parallel with the attenuation of the radiation-induced therapeutic effect against the tumor. This indicates that DLN are essential for the activation and accumulation of radiation-induced CTL, which are essential for inhibition of the tumor. A combined therapy of local radiation with Th1 cell therapy augmented the generation of tumor-specific CTL at the tumor site and induced a complete regression of the tumor, although radiation therapy alone did not exhibit such a pronounced therapeutic effect. Thus, we conclude that the combination treatment of local radiation therapy and Th1 cell therapy is a rational strategy to augment antitumor activity mediated by tumor-specific CTL. Cancer Res; 70(7); 2697–706
Data from Variable Inhibition of Thrombospondin 1 against Liver and Lung Metastases through Differential Activation of Metalloproteinase ADAMTS1
Authors: Lee Yoon-Jin , Koch Moritz , Karl Daniel , Torres-Collado Antoni X. , Fernando Namali T. , Rothrock Courtney , Kuruppu Darshini , Ryeom Sandra , Iruela-Arispe M. Luisa , Yoon Sam S.
Published: March 2024

Abstract
Metastasis relies on angiogenesis for tumor expansion. Tumor angiogenesis is restrained by a variety of endogenous inhibitors, including thrombospondin 1 (TSP1). The principal antiangiogenic activity of TSP1 resides in a domain containing three TSP1 repeats (3TSR), and TSP1 cleavage is regulated, in part, by the metalloproteinase ADAMTS1. In this study, we examined the role of TSP1 and ADAMTS1 in controlling metastatic disease in the liver and lung. TSP1 overexpression inhibited metastatic growth of colon or renal carcinoma cells in liver but not lung. Metastatic melanoma in liver grew more rapidly in Tsp1-null mice compared with controls, whereas in lung grew similarly in Tsp1-null mice or controls. Recombinant TSP1 was cleaved more efficiently in lysates from liver than lung. ADAMTS1 inhibition by neutralizing antibody, small interfering RNA, or genetic deletion abrogated cleavage activity. To confirm that lack of cleavage of TSP1 ablated its antiangiogenic function in the lung, we generated colon cancer cells stably secreting only the 3TSR domain and found that they inhibited formation of both liver and lung metastases. Collectively, our results indicate that the antiangiogenic activity of TSP1 is differentially regulated by ADAMTS1 in the liver and lung, emphasizing the concept that regulation of angiogenesis is varied in different tissue environments. Cancer Res; 70(3); 948–56
Data from 5-Fluorouracil Selectively Kills Tumor-Associated Myeloid-Derived Suppressor Cells Resulting in Enhanced T Cell–Dependent Antitumor Immunity
Authors: Vincent Julie , Mignot Grégoire , Chalmin Fanny , Ladoire Sylvain , Bruchard Mélanie , Chevriaux Angélique , Martin François , Apetoh Lionel , Rébé Cédric , Ghiringhelli François
Published: March 2024

Abstract
Myeloid-derived suppressor cells (MDSC) accumulate in the spleen and tumor bed during tumor growth. They contribute to the immune tolerance of cancer notably by inhibiting the function of CD8(+) T cells. Thus, their elimination may hamper tumor growth by enhancing antitumor T-cell functions. We have previously reported that some anticancer agents relied on T cell–dependent anticancer responses to achieve maximal efficacy. However, the effect of anticancer agents on MDSC has remained largely unexplored. In this study, we observed that gemcitabine and 5-fluorouracil (5FU) were selectively cytotoxic on MDSC. In vivo, the treatment of tumor-bearing mice with 5FU led to a major decrease in the number of MDSC in the spleens and tumor beds of animals whereas no significant effect on T cells, natural killer cells, dendritic cells, or B cells was noted. Interestingly, 5FU showed a stronger efficacy over gemcitabine to deplete MDSC and selectively induced MDSC apoptotic cell death in vitro and in vivo. The elimination of MDSC by 5FU increased IFN-γ production by tumor-specific CD8(+) T cells infiltrating the tumor and promoted T cell–dependent antitumor responses in vivo. Altogether, these findings suggest that the antitumor effect of 5FU is mediated, at least in part, by its selective cytotoxic action on MDSC. Cancer Res; 70(8); 3052–61. ©2010 AACR.
Data from hsa-miR-29c* Is Linked to the Prognosis of Malignant Pleural Mesothelioma
Authors: Pass Harvey I. , Goparaju Chandra , Ivanov Sergey , Donington Jessica , Carbone Michele , Hoshen Moshe , Cohen Dalia , Chajut Ayelet , Rosenwald Shai , Dan Harel , Benjamin Sima , Aharonov Ranit
Published: March 2024

Abstract
The inability to forecast outcomes for malignant mesothelioma prevents clinicians from providing aggressive multimodality therapy to the most appropriate individuals who may benefit from such an approach. We investigated whether specific microRNAs (miR) could segregate a largely surgically treated group of mesotheliomas into good or bad prognosis categories. A training set of 44 and a test set of 98 mesothelioma tumors were analyzed by a custom miR platform, along with 9 mesothelioma cell lines and 3 normal mesothelial lines. Functional implications as well as downstream targets of potential prognostic miRs were investigated. In both the training and test sets, hsa-miR-29c* was an independent prognostic factor for time to progression as well as survival after surgical cytoreduction. The miR was expressed at higher levels in epithelial mesothelioma, and the level of this miR could segregate patients with this histology into groups with differing prognosis. Increased expression of hsa-miR-29c* predicted a more favorable prognosis, and overexpression of the miR in mesothelioma cell lines resulted in significantly decreased proliferation, migration, invasion, and colony formation. Moreover, major epigenetic regulation of mesothelioma is mediated by hsa-miR-29c* and was shown through downregulation of DNA methyltransferases as well as upregulation of demethylating genes. A single miR has the potential to be a prognostic biomarker in mesothelioma, and validation of these findings as well as investigation of its downstream targets may give insight for potential therapies in the future. Cancer Res; 70(5); 1916–24
Data from BRCA1 Represses Amphiregulin Gene Expression
Authors: Lamber Ekaterina P. , Horwitz Andrew A. , Parvin Jeffrey D.
Published: March 2024

Abstract
BRCA1, the breast cancer- and ovarian cancer-specific tumor suppressor, can be a transcriptional repressor or a transcriptional activator, depending on the promoter context. To identify the genes activated or repressed by BRCA1, we have analyzed microarray results from cells depleted of BRCA1 and revealed a number of genes regulated by BRCA1 on the level of transcription. Among the genes repressed by BRCA1, we have identified amphiregulin (AREG) and early growth response-1 (EGR1). Results indicate that BRCA1 regulates AREG transcription directly through binding to the AREG promoter, however, we could not detect BRCA1 on the EGR1 promoter, suggesting that EGR1 is indirectly regulated by BRCA1. In an attempt to identify the mechanism of the AREG transcriptional repression by BRCA1, we have mapped two independent BRCA1 response elements on the AREG located at positions −202/−182 and +19/+122. BRCA1 depletion leads to induction of the AREG protein. Taken together, our data build the connection between BRCA1 loss of function and AREG upregulation—a change in gene expression often observed in breast cancer. Cancer Res; 70(3); 996–1005
Data from Ectopic Expression of X-Linked Lymphocyte-Regulated Protein pM1 Renders Tumor Cells Resistant to Antitumor Immunity
Authors: Kang Tae Heung , Noh Kyung Hee , Kim Jin Hee , Bae Hyun Cheol , Lin Ken Y. , Monie Archana , Pai Sara I. , Hung Chien-Fu , Wu T.-C. , Kim Tae Woo
Published: March 2024

Abstract
Tumor immune escape is a major obstacle in cancer immunotherapy, but the mechanisms involved remain poorly understood. We have previously developed an immune evasion tumor model using an in vivo immune selection strategy and revealed Akt-mediated immune resistance to antitumor immunity induced by various cancer immunotherapeutic agents. In the current study, we used microarray gene analysis to identify an Akt-activating candidate molecule overexpressed in immune-resistant tumors compared with parental tumors. X-linked lymphocyte-regulated protein pM1 (XLR) gene was the most upregulated in immune-resistant tumors compared with parental tumor cells. Furthermore, the retroviral transduction of XLR in parental tumor cells led to activation of Akt, resulting in upregulation of antiapoptotic proteins and the induction of immune resistance phenotype in parental tumor cells. In addition, we found that transduction of parental tumor cells with other homologous genes from the mouse XLR family, such as synaptonemal complex protein 3 (SCP3) and XLR-related, meiosis-regulated protein (XMR) and its human counterpart of SCP3 (hSCP3), also led to activation of Akt, resulting in the upregulation of antiapoptotic proteins and induction of immune resistance phenotype. Importantly, characterization of a panel of human cervical cancers revealed relatively higher expression levels of hSCP3 in human cervical cancer tissue compared with normal cervical tissue. Thus, our data indicate that ectopic expression of XLR and its homologues in tumor cells represents a potentially important mechanism for tumor immune evasion and serves as a promising molecular target for cancer immunotherapy. Cancer Res; 70(8); 3062–70. ©2010 AACR.
Data from Using a Stem Cell–Based Signature to Guide Therapeutic Selection in Cancer
Authors: Shats Igor , Gatza Michael L. , Chang Jeffrey T. , Mori Seiichi , Wang Jialiang , Rich Jeremy , Nevins Joseph R.
Published: March 2024

Abstract
Given the very substantial heterogeneity of most human cancers, it is likely that most cancer therapeutics will be active in only a small fraction of any population of patients. As such, the development of new therapeutics, coupled with methods to match a therapy with the individual patient, will be critical to achieving significant gains in disease outcome. One such opportunity is the use of expression signatures to identify key oncogenic phenotypes that can serve not only as biomarkers but also as a means of identifying therapeutic compounds that might specifically target these phenotypes. Given the potential importance of targeting tumors exhibiting a stem-like phenotype, we have developed an expression signature that reflects common biological aspects of various stem-like characteristics. The consensus stemness ranking (CSR) signature is upregulated in cancer stem cell–enriched samples at advanced tumor stages and is associated with poor prognosis in multiple cancer types. Using two independent computational approaches we utilized the CSR signature to identify clinically useful compounds that could target the CSR phenotype. In vitro assays confirmed selectivity of several predicted compounds including topoisomerase inhibitors and resveratrol towards breast cancer cell lines that exhibit a high-CSR phenotype. Importantly, the CSR signature could predict clinical response of breast cancer patients to a neoadjuvant regimen that included a CSR-specific agent. Collectively, these results suggest therapeutic opportunities to target the CSR phenotype in a relevant cohort of cancer patients. Cancer Res; 71(5); 1772–80. ©2010 AACR.
Data from Human RecQL4 Helicase Plays Critical Roles in Prostate Carcinogenesis
Authors: Su Yanrong , Meador Jarah A. , Calaf Gloria M. , De-Santis Luca Proietti , Zhao Yongliang , Bohr Vilhelm A. , Balajee Adayabalam S.
Published: March 2024

Abstract
Prostate cancer is the second leading cause of cancer-associated deaths among men in the western countries. Here, we report that human RecQL4 helicase, which is implicated in the pathogenesis of a subset of cancer-prone Rothmund-Thomson syndrome, is highly elevated in metastatic prostate cancer cell lines. Increased RecQL4 expression was also detected in human prostate tumor tissues as a function of tumor grade with the highest expression level in metastatic tumor samples, suggesting that RecQL4 may be a potential prognostic factor for advanced stage of prostate cancer. Transient and stable suppression of RecQL4 by small interfering RNA and short hairpin RNA vectors drastically reduced the growth and survival of metastatic prostate cancer cells, indicating that RecQL4 is a prosurvival factor for prostate cancer cells. RecQL4 suppression led to increased poly(ADP-ribose) polymerase (PARP) synthesis and RecQL4-suppressed prostate cancer cells underwent an extensive apoptotic death in a PARP-1–dependent manner. Most notably, RecQL4 knockdown in metastatic prostate cancer cells drastically reduced their cell invasiveness in vitro and tumorigenicity in vivo, showing that RecQL4 is essential for prostate cancer promotion. Observation of a direct interaction of retinoblastoma (Rb) and E2F1 proteins with RecQL4 promoter suggests that Rb-E2F1 pathway may regulate RecQL4 expression. Collectively, our study shows that RecQL4 is an essential factor for prostate carcinogenesis. Cancer Res; 70(22); 9207–17. ©2010 AACR.
Data from Proteomic Characterization of Novel Alternative Splice Variant Proteins in Human Epidermal Growth Factor Receptor 2/neu–Induced Breast Cancers
Authors: Menon Rajasree , Omenn Gilbert S.
Published: March 2024

Abstract
Multifaceted alternative splicing in cancer cells greatly diversifies protein structure independently of genome changes, but the characterization of cancer-associated splice variants is quite limited. In this study, we used mass spectrometric data to interrogate a custom-built database created with three-frame translations of mRNA sequences from Ensembl and ECgene to find alternative splice variant proteins. In mass spectrometric files from liquid chromatography tandem mass spectrometry (LC-MS/MS) analyses of normal mouse mammary glands or mammary tumors derived from conditional human epidermal growth factor receptor 2 (Her2)/neu transgenic mice, we identified a total of 608 alternative splice variants, of which peptides from 216 proteins were found only in the tumor sample. Among the 608 splice variants were 68 novel proteins that were not completely matched to any known protein sequence in mice, for which we found known functional motifs. Biological process enrichment analysis of the splice variants identified suggested the involvement of these proteins especially in cell motility and translation initiation. The cancer-associated differentially expressed splice variant proteins offer novel biomarker candidates that may function in breast cancer progression or metastasis. Cancer Res; 70(9); 3440–9. ©2010 AACR.
Data from The Immunosuppressive Surface Ligand CD200 Augments the Metastatic Capacity of Squamous Cell Carcinoma
Authors: Stumpfova Magda , Ratner Desirée , Desciak Edward B. , Eliezri Yehuda D. , Owens David M.
Published: March 2024

Abstract
CD200 (OX-2) is a cell surface glycoprotein that imparts immune privileges by suppressing alloimmune and autoimmune responses through its receptor, CD200R, expressed primarily on myeloid cells. The ability of CD200 to suppress myeloid cell activation is critical for maintaining normal tissue homeostasis but may also enhance the survival of migratory neoplastic cells. We show that CD200 expression is largely absent in well-differentiated primary squamous cell carcinoma (SCC) of the skin, but is highly induced in SCC metastases to the lymph node and other solid tissues. CD200 does not influence the proliferative or invasive capacity of SCC cells or their ability to reconstitute primary skin tumors. However, loss of CD200 impairs the ability of SCC cells to metastasize and seed secondary tumors, indicating that the survival of CD200+ SCC cells may depend on their ability to interact with CD200R+ immune cells. The predominant population of CD200R+ stromal cells was CD11b+Gr-1+ myeloid-derived suppressor cells, which release elevated levels of granulocyte colony-stimulating factor and granulocyte macrophage colony-stimulating factor when in the presence of SCC cells in a CD200-dependent manner. Collectively, our findings implicate CD200 as a hallmark of SCC metastasis and suggest that the ability of CD200+ SCC keratinocytes to directly engage and modulate CD200R+ myeloid-derived suppressor cells is essential to metastatic survival. Cancer Res; 70(7); 2962–72
Data from Reexpression of hSNF5 in Malignant Rhabdoid Tumor Cell Lines Causes Cell Cycle Arrest through a p21CIP1/WAF1-Dependent Mechanism
Authors: Kuwahara Yasumichi , Charboneau Aubri , Knudsen Erik S. , Weissman Bernard E.
Published: March 2024

Abstract
Loss of hSNF5 function is usually observed in malignant rhabdoid tumor (MRT), a highly aggressive pediatric neoplasm. Previous studies have shown that reexpression of hSNF5 in MRT cell lines causes G1 cell cycle arrest with p16INK4A, p21CIP1/WAF1, and cyclin D1 playing key roles in MRT cell growth control. However, we have shown that reexpression of hSNF5 induced cell cycle arrest in the absence of p16INK4A expression. These results indicate that the mechanism of hSNF5-induced cell cycle arrest is context dependent. Here, we investigated the relationship between p21CIP1/WAF1 and hSNF5 in the regulation of growth using several MRT cell lines. We found that G1 cell cycle arrest occurred concomitant with an increase in p21CIP1/WAF1 mRNA and protein levels and preceded p16INK4A mRNA and protein upregulation. Chromatin immunoprecipitation data confirmed that hSNF5 appeared at both p21CIP1/WAF1 and p16INK4A promoters after reexpression. We further showed that p21CIP1/WAF1 induction showed both p53-dependent and p53-independent mechanisms. We also showed that reduction of p21CIP1/WAF1 expression by RNAi significantly inhibited hSNF5-induced G1 arrest. Our results show that both p21CIP1/WAF1 and p16INK4A are targets for hSNF5 and that p21CIP1/WAF1 upregulation during hSNF5-induced G1 arrest precedes p16INK4A upregulation. These findings indicate that SNF5 mediates a temporally controlled program of cyclin-dependent kinase inhibition to restrict aberrant proliferation in MRT cells. Cancer Res; 70(5); 1854–65
Data from The Adaptor Protein AMOT Promotes the Proliferation of Mammary Epithelial Cells via the Prolonged Activation of the Extracellular Signal-Regulated Kinases
Authors: Ranahan William P. , Han Zhang , Smith-Kinnaman Whitney , Nabinger Sarah C. , Heller Brigitte , Herbert Britney-Shea , Chan Rebecca , Wells Clark D.
Published: March 2024

Abstract
The asymmetric organization of epithelial cells is a basic counter to cellular proliferation. However, the mechanisms whereby pro-growth pathways are modulated by intracellular factors that control cell shape are not well understood. This study demonstrates that the adaptor protein Amot, in addition to its established role in regulating cellular asymmetry, also promotes extracellular signal-regulated kinase 1 and 2 (ERK1/2)–dependent proliferation of mammary cells. Specifically, expression of Amot80, but not a mutant lacking its polarity protein interaction domain, enhances ERK1/2-dependent proliferation of MCF7 cells. Further, expression of Amot80 induces nontransformed MCF10A cells to overgrow as disorganized cellular aggregates in Matrigel. Conversely, Amot expression is required for proliferation of breast cancer cells in specific microenvironmental contexts that require ERK1/2 signaling. Thus, Amot is proposed to coordinate the dysregulation of cell polarity with the induction of neoplastic growth in mammary cells. Cancer Res; 71(6); 2203–11. ©2011 AACR.
Data from Identification of a Cholangiocarcinoma-Like Gene Expression Trait in Hepatocellular Carcinoma
Authors: Woo Hyun Goo , Lee Jeong-Hoon , Yoon Jung-Hwan , Kim Chung Yong , Lee Hyo-Suk , Jang Ja June , Yi Nam-Joon , Suh Kyung-Suk , Lee Kuhn Uk , Park Eun Sung , Thorgeirsson Snorri S. , Kim Yoon Jun
Published: March 2024

Abstract
Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) are the major adult liver cancers. The existence of combined hepatocellular-cholangiocarcinoma (CHC), a histopathologic intermediate form between HCC and CC, suggests phenotypic overlap between these tumors. Here, we applied an integrative oncogenomic approach to address the clinical and functional implications of the overlapping phenotype between these tumors. By performing gene expression profiling of human HCC, CHC, and CC, we identified a novel HCC subtype, i.e., cholangiocarcinoma-like HCC (CLHCC), which expressed cholangiocarcinoma-like traits (CC signature). Similar to CC and CHC, CLHCC showed an aggressive phenotype with shorter recurrence-free and overall survival. In addition, we found that CLHCC coexpressed embryonic stem cell–like expression traits (ES signature) suggesting its derivation from bipotent hepatic progenitor cells. By comparing the expression of CC signature with previous ES-like, hepatoblast-like, or proliferation-related traits, we observed that the prognostic value of the CC signatures was independent of the expression of those signatures. In conclusion, we suggest that the acquisition of cholangiocarcinoma-like expression traits plays a critical role in the heterogeneous progression of HCC. Cancer Res; 70(8); 3034–41. ©2010 AACR.
Data from Smad Signaling Is Required to Maintain Epigenetic Silencing during Breast Cancer Progression
Authors: Papageorgis Panagiotis , Lambert Arthur W. , Ozturk Sait , Gao Fangming , Pan Hongjie , Manne Upender , Alekseyev Yuriy O. , Thiagalingam Arunthathi , Abdolmaleky Hamid M. , Lenburg Marc , Thiagalingam Sam
Published: March 2024

Abstract
Breast cancer progression is associated with aberrant DNA methylation and expression of genes that control the epithelial-mesenchymal transition (EMT), a critical step in malignant conversion. Although the genes affected have been studied, there is little understanding of how aberrant activation of the DNA methylation machinery itself occurs. Using a breast cancer cell–based model system, we found that cells that underwent EMT exhibited overactive transforming growth factor β (TGFβ) signaling and loss of expression of the CDH1, CGN, CLDN4, and KLK10 genes as a result of hypermethylation of their corresponding promoter regions. Based on these observations, we hypothesized that activated TGFβ-Smad signaling provides an “epigenetic memory” to maintain silencing of critical genes. In support of this hypothesis, disrupting Smad signaling in mesenchymal breast cancer cells resulted in DNA demethylation and reexpression of the genes identified. This epigenetic reversal was accompanied by an acquisition of epithelial morphology and a suppression of invasive properties. Notably, disrupting TGFβ signaling decreased the DNA binding activity of DNA methyltransferase DNMT1, suggesting that failure to maintain methylation of newly synthesized DNA was the likely cause of DNA demethylation. Together, our findings reveal a hyperactive TGFβ-TGFβR-Smad2 signaling axis needed to maintain epigenetic silencing of critical EMT genes and breast cancer progression. Cancer Res; 70(3); 968–78
Data from Malignant Germ Cell Tumors Display Common MicroRNA Profiles Resulting in Global Changes in Expression of Messenger RNA Targets
Authors: Palmer Roger D. , Murray Matthew J. , Saini Harpreet K. , van Dongen Stijn , Abreu-Goodger Cei , Muralidhar Balaji , Pett Mark R. , Thornton Claire M. , Nicholson James C. , Enright Anton J. , Coleman Nicholas
Published: March 2024

Abstract
Despite their extensive clinical and pathologic heterogeneity, all malignant germ cell tumors (GCT) are thought to originate from primordial germ cells. However, no common biological abnormalities have been identified to date. We profiled 615 microRNAs (miRNA) in pediatric malignant GCTs, controls, and GCT cell lines (48 samples in total) and re-analyzed available miRNA expression data in adult gonadal malignant GCTs. We applied the bioinformatic algorithm Sylamer to identify miRNAs that are of biological importance by inducing global shifts in mRNA levels. The most significant differentially expressed miRNAs in malignant GCTs were all from the miR-371–373 and miR-302 clusters (adjusted P < 0.00005), which were overexpressed regardless of histologic subtype [yolk sac tumor (YST)/seminoma/embryonal carcinoma (EC)], site (gonadal/extragonadal), or patient age (pediatric/adult). Sylamer revealed that the hexamer GCACTT, complementary to the 2- to 7-nucleotide miRNA seed AAGUGC shared by six members of the miR-371–373 and miR-302 clusters, was the only sequence significantly enriched in the 3′-untranslated region of mRNAs downregulated in pediatric malignant GCTs (as a group), YSTs and ECs, and in adult YSTs (all versus nonmalignant tissue controls; P < 0.05). For the pediatric samples, downregulated genes containing the 3′-untranslated region GCACTT showed significant overrepresentation of Gene Ontology terms related to cancer-associated processes, whereas for downregulated genes lacking GCACTT, Gene Ontology terms generally represented metabolic processes only, with few genes per term (adjusted P < 0.05). We conclude that the miR-371–373 and miR-302 clusters are universally overexpressed in malignant GCTs and coordinately downregulate mRNAs involved in biologically significant pathways. Cancer Res; 70(7); 2911–23
Data from Regulation of the MicroRNA Processor DGCR8 by the Tumor Suppressor ING1
Authors: Gómez-Cabello Daniel , Callejas Sergio , Benguría Alberto , Moreno Alberto , Alonso Javier , Palmero Ignacio
Published: March 2024

Abstract
The ING family of tumor suppressor proteins controls several cellular functions relevant to antitumor protection, such as cell cycle control, apoptosis, senescence, or migration. ING proteins are functionally linked to the p53 pathway, and they participate in transcriptional control via the recognition of histone marks and recruitment of protein complexes with chromatin-modifying activity to specific promoters. Here, we have investigated the global effect of ING1 in gene regulation through genome-wide analysis of expression profiles in primary embryonic fibroblasts deficient for the Ing1 locus. We find that Ing1 has a predominant role as transcriptional repressor in this setting, affecting the expression of genes involved in a variety of cellular functions. Within the subset of genes showing differential expression, we have identified DGCR8, a protein involved in the early steps of microRNA biogenesis. We show that ING1 binds to the DGCR8 promoter and controls its transcription through chromatin regulation. We also find that ING1 and DGCR8 can cooperate in restraining proliferation. In summary, this study reveals a novel connection between ING1 and a regulator of microRNA biogenesis and identifies new links between tumor suppressor proteins and the microRNA machinery. Cancer Res; 70(5); 1866–74
Data from VHL Gene Mutations and Their Effects on Hypoxia Inducible Factor HIFα: Identification of Potential Driver and Passenger Mutations
Authors: Rechsteiner Markus P. , von Teichman Adriana , Nowicka Anna , Sulser Tullio , Schraml Peter , Moch Holger
Published: March 2024

Abstract
Mutations of the von Hippel-Lindau (VHL) gene are frequent in clear cell renal cell carcinomas (ccRCC). Nonsense and frameshift mutations abrogate the function of the VHL protein (pVHL), whereas missense mutations can have different effects. To identify those missense mutations with functional consequences, we sequenced VHL in 256 sporadic ccRCC and identified 187 different VHL mutations of which 65 were missense mutations. Location and destabilizing effects of VHL missense mutations were determined in silico. The majority of the thermodynamically destabilizing missense mutations were located in exon 1 in the core of pVHL, whereas protein surface mutations in exon 3 affected the interaction domains of elongin B and C. Their impact on pVHL's functionality was further investigated in vitro by stably reintroducing VHL missense mutations into a VHL null cell line and by monitoring the green fluorescent protein (GFP) signals after the transfection of a hypoxia inducible factor (HIF)α-GFP expression vector. pVHL's functionality ranged from no effect to complete HIF stabilization. Interestingly, Asn78Ser, Asp121Tyr, and Val130Phe selectively influenced HIF1α and HIF2α degradation. In summary, we obtained three different groups of missense mutations: one with severe destabilization of pVHL; a second without destabilizing effects on pVHL but relevance for the interaction with HIFα, elongin B, and elongin C; and a third with pVHL functions comparable with wild type. We therefore conclude that the specific impact of missense mutations may help to distinguish between driver and passenger mutations and may explain responses of ccRCC patients to HIF-targeted therapies. Cancer Res; 71(16); 5500–11. ©2011 AACR.
Data from Genome-wide Analysis of Novel Splice Variants Induced by Topoisomerase I Poisoning Shows Preferential Occurrence in Genes Encoding Splicing Factors
Authors: Solier Stéphanie , Barb Jennifer , Zeeberg Barry R. , Varma Sudhir , Ryan Mike C. , Kohn Kurt W. , Weinstein John N. , Munson Peter J. , Pommier Yves
Published: March 2024

Abstract
RNA splicing is required to remove introns from pre-mRNA, and alternative splicing generates protein diversity. Topoisomerase I (Top1) has been shown to be coupled with splicing by regulating serine/arginine-rich splicing proteins. Prior studies on isolated genes also showed that Top1 poisoning by camptothecin (CPT), which traps Top1 cleavage complexes (Top1cc), can alter RNA splicing. Here, we tested the effect of Top1 inhibition on splicing at the genome-wide level in human colon carcinoma HCT116 and breast carcinoma MCF7 cells. The RNA of HCT116 cells treated with CPT for various times was analyzed with ExonHit Human Splice Array. Unlike other exon array platforms, the ExonHit arrays include junction probes that allow the detection of splice variants with high sensitivity and specificity. We report that CPT treatment preferentially affects the splicing of splicing-related factors, such as RBM8A, and generates transcripts coding for inactive proteins lacking key functional domains. The splicing alterations induced by CPT are not observed with cisplatin or vinblastine and are not simply due to reduced Top1 activity, as Top1 downregulation by short interfering RNA did not alter splicing like CPT treatment. Inhibition of RNA polymerase II (Pol II) hyperphosphorylation by 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole (DRB) blocked the splicing alteration induced by CPT, which suggests that the rapid Pol II hyperphosphorylation induced by CPT interferes with normal splicing. The preferential effect of CPT on genes encoding splicing factors may explain the abnormal splicing of a large number of genes in response to Top1cc. Cancer Res; 70(20); 8055–65. ©2010 AACR.
Data from Identification of Aldo-Keto Reductase AKR1B10 as a Selective Target for Modification and Inhibition by Prostaglandin A1: Implications for Antitumoral Activity
Authors: Díez-Dacal Beatriz , Gayarre Javier , Gharbi Severine , Timms John F. , Coderch Claire , Gago Federico , Pérez-Sala Dolores
Published: March 2024

Abstract
Cyclopentenone prostaglandins (cyPG) are reactive eicosanoids that may display anti-inflammatory and antiproliferative actions, possibly offering therapeutic potential. Here we report the identification of members of the aldo-keto reductase (AKR) family as selective targets of the cyPG prostaglandin A1 (PGA1). AKR enzymes metabolize aldehydes and drugs containing carbonyl groups and are involved in inflammation and tumorigenesis. Thus, these enzymes represent a class of targets to develop small molecule inhibitors with therapeutic activity. Molecular modeling studies pointed to the covalent binding of PGA1 to Cys299, close to the active site of AKR, with His111 and Tyr49, which are highly conserved in the AKR family, playing a role in PGA1 orientation. Among AKR enzymes, AKR1B10 is considered as a tumor marker and contributes to tumor development and chemoresistance. We validated the direct modification of AKR1B10 by biotinylated PGA1 (PGA1-B) in cells, and confirmed that mutation of Cys299 abolishes PGA1-B incorporation, whereas substitution of His111 or Tyr49 reduced the interaction. Modification of AKR1B10 by PGA1 correlated with loss of enzymatic activity and both effects were increased by depletion of cellular glutathione. Moreover, in lung cancer cells PGA1 reduced tumorigenic potential and increased accumulation of the AKR substrate doxorubicin, potentiating cell-cycle arrest induced by this chemotherapeutic agent. Our findings define PGA1 as a new AKR inhibitor and they offer a framework to develop compounds that could counteract cancer chemoresistance. Cancer Res; 71(12); 4161–71. ©2011 AACR.
Data from Akt-Dependent Glucose Metabolism Promotes Mcl-1 Synthesis to Maintain Cell Survival and Resistance to Bcl-2 Inhibition
Authors: Coloff Jonathan L. , Macintyre Andrew N. , Nichols Amanda G. , Liu Tingyu , Gallo Catherine A. , Plas David R. , Rathmell Jeffrey C.
Published: March 2024

Abstract
Most cancer cells utilize aerobic glycolysis, and activation of the phosphoinositide 3-kinase/Akt/mTOR pathway can promote this metabolic program to render cells glucose dependent. Although manipulation of glucose metabolism may provide a means to specifically eliminate cancer cells, mechanistic links between cell metabolism and apoptosis remain poorly understood. Here, we examined the role and metabolic regulation of the antiapoptotic Bcl-2 family protein Mcl-1 in cell death upon inhibition of Akt-induced aerobic glycolysis. In the presence of adequate glucose, activated Akt prevented the loss of Mcl-1 expression and protected cells from growth factor deprivation-induced apoptosis. Mcl-1 associated with and inhibited the proapoptotic Bcl-2 family protein Bim, contributing to cell survival. However, suppression of glucose metabolism led to induction of Bim, decreased expression of Mcl-1, and apoptosis. The proapoptotic Bcl-2/Bcl-xL/Bcl-w inhibitor, ABT-737, shows clinical promise, but Mcl-1 upregulation can promote resistance. Importantly, inhibition of glucose metabolism or mTORC1 overcame Mcl-1–mediated resistance in diffuse large B cell leukemic cells. Together these data show that Mcl-1 protein synthesis is tightly controlled by metabolism and that manipulation of glucose metabolism may provide a mechanism to suppress Mcl-1 expression and sensitize cancer cells to apoptosis. Cancer Res; 71(15); 5204–13. ©2011 AACR.
Data from Gadd45a Functions as a Promoter or Suppressor of Breast Cancer Dependent on the Oncogenic Stress
Authors: Tront Jennifer S. , Huang Yajue , Fornace Albert A. , Hoffman Barbara , Liebermann Dan A.
Published: March 2024

Abstract
Gadd45a plays a pivotal role as a stress sensor that modulates cellular responses to various stress stimuli including oncogenic stress. We reported that the stress sensor Gadd45a gene functions as a tumor suppressor in Ras-driven breast tumorigenesis via increasing JNK-mediated apoptosis and p38-mediated senescence. In contrast, here, we show that Gadd45a promotes Myc-driven breast cancer by negatively regulating MMP10 via GSK3 β/β-catenin signaling, resulting in increased tumor vascularization and growth. These novel findings indicate that Gadd45a functions as either tumor promoter or suppressor, is dependent on the oncogenic stress, and is mediated via distinct signaling pathways. Collectively, these novel findings highlight the significance of the type of oncogenic alteration on how stress response genes function during initiation and progression of tumorigenesis. Because Gadd45a is a target for BRCA1 and p53, these findings have implications regarding BRCA1/p53 tumor suppressor functions. Cancer Res; 70(23); 9671–81. ©2010 AACR.
Data from CXCR3 Enhances a T-Cell–Dependent Epidermal Proliferative Response and Promotes Skin Tumorigenesis
Authors: Winkler Ashley E. , Brotman Joshua J. , Pittman Meredith E. , Judd Nancy P. , Lewis James S. , Schreiber Robert D. , Uppaluri Ravindra
Published: March 2024

Abstract
The chemokine receptor CXCR3 has been proposed to play a critical role in host antitumor responses. In this study, we defined CXCR3-expressing immune cell infiltration in human skin squamous cell carcinomas and then used CXCR3-deficient mice to assess the contribution of CXCR3 to skin tumorigenesis. Our studies employed two established protocols for chemical skin carcinogenesis [methylcholanthrene (MCA) or 7,12-dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA) models]. CXCR3 deletion did not affect tumor development in the MCA model; however, CXCR3 was important in the DMBA/TPA model where gene deletion reduced the incidence of skin tumors. This decreased incidence of skin tumors did not reflect differences in epidermal development but rather was associated with reduced epidermal thickness and proliferation in CXCR3−/− mice, implicating the CXCR3 pathway in DMBA/TPA-induced epidermal inflammation and proliferation. Notably, CXCR3 expressed in CD4+ and CD8+ T cells was found to be important for enhanced epidermal proliferation. Specifically, CXCR3-deficient mice reconstituted with T cells isolated from wild-type mice treated with DMBA/TPA restored wild-type levels of epidermal proliferation in the mutant mice. Taken together, our findings establish that CXCR3 promotes epidermal tumorigenesis likely through a T-cell–dependent induction of keratinocyte proliferation. Cancer Res; 71(17); 5707–16. ©2011 AACR.
Data from Ron Kinase Transphosphorylation Sustains MET Oncogene Addiction
Authors: Benvenuti Silvia , Lazzari Luca , Arnesano Addolorata , Li Chiavi Giulia , Gentile Alessandra , Comoglio Paolo M.
Published: March 2024

Abstract
Receptors for the scatter factors HGF and MSP that are encoded by the MET and RON oncogenes are key players in invasive growth. Receptor cross-talk between Met and Ron occurs. Amplification of the MET oncogene results in kinase activation, deregulated expression of an invasive growth phenotype, and addiction to MET oncogene signaling (i.e., dependency on sustained Met signaling for survival and proliferation). Here we show that cancer cells addicted to MET also display constitutive activation of the Ron kinase. In human cancer cell lines coexpressing the 2 oncogenes, Ron is specifically transphosphorylated by activated Met. In contrast, Ron phosphorylation is not triggered in cells harboring constitutively active kinase receptors other than Met, including Egfr or Her2. Furthermore, Ron phosphorylation is suppressed by Met-specific kinase inhibitors (PHA-665752 or JNJ-38877605). Last, Ron phosphorylation is quenched by reducing cell surface expression of Met proteins by antibody-induced shedding. In MET-addicted cancer cells, short hairpin RNA–mediated silencing of RON expression resulted in decreased proliferation and clonogenic activity in vitro and tumorigenicity in vivo. Our findings establish that oncogene addiction to MET involves Ron transactivation, pointing to Ron kinase as a target for combinatorial cancer therapy. Cancer Res; 71(5); 1945–55. ©2011 AACR.