bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Characterization of the Oncogenic Activity of the Novel TRIM59 Gene in Mouse Cancer Models
Authors: Valiyeva Fatma , Jiang Fei , Elmaadawi Ahmed , Moussa Madeleine , Yee Siu-Pok , Raptis Leda , Izawa Jonathan I. , Yang Burton B. , Greenberg Norman M. , Wang Fen , Xuan Jim W.
Published: March 2024

Abstract
A novel TRIM family member, TRIM59 gene was characterized to be upregulated in SV40 Tag oncogene–directed transgenic and knockout mouse prostate cancer models as a signaling pathway effector. We identified two phosphorylated forms of TRIM59 (p53 and p55) and characterized them using purified TRIM59 proteins from mouse prostate cancer models at different stages with wild-type mice and NIH3T3 cells as controls. p53/p55-TRIM59 proteins possibly represent Ser/Thr and Tyr phosphorylation modifications, respectively. Quantitative measurements by ELISA showed that the p-Ser/Thr TRIM59 correlated with tumorigenesis, whereas the p-Tyr-TRIM59 protein correlated with advanced cancer of the prostate (CaP). The function of TRIM59 was elucidated using short hairpin RNA (shRNA)-mediated knockdown of the gene in human CaP cells, which caused S-phase cell-cycle arrest and cell growth retardation. A hit-and-run effect of TRIM59 shRNA knockdown was observed 24 hours posttransfection. Differential cDNA microarrray analysis was conducted, which showed that the initial and rapid knockdown occurred early in the Ras signaling pathway. To confirm the proto-oncogenic function of TRIM59 in the Ras signaling pathway, we generated a transgenic mouse model using a prostate tissue–specific gene (PSP94) to direct the upregulation of the TRIM59 gene. Restricted TRIM59 gene upregulation in the prostate revealed the full potential for inducing tumorigenesis, similar to the expression of SV40 Tag, and coincided with the upregulation of genes specific to the Ras signaling pathway and bridging genes for SV40 Tag–mediated oncogenesis. The finding of a possible novel oncogene in animal models will implicate a novel strategy for diagnosis, prognosis, and therapy for cancer. Mol Cancer Ther; 10(7); 1229–40. ©2011 AACR.
Data from Molecular and Cellular Pharmacology of the Novel Noncamptothecin Topoisomerase I Inhibitor Genz-644282
Authors: Sooryakumar Dhriti , Dexheimer Thomas S. , Teicher Beverly A. , Pommier Yves
Published: March 2024

Abstract
Camptothecin derivatives are powerful anticancer drugs because of their ability to trap topoisomerase I (Top1)–DNA cleavage complexes. However, they exhibit clinical limitations due to the instability of their α-hydroxylactone six-membered E-ring structure. In addition, they exhibit bone marrow and intestinal toxicity, especially in adults, and are drug efflux substrates. Here, we report a novel Top1 inhibitor, Genz-644282. We show that Genz-644282 and its metabolites induce Top1 cleavage at similar, as well as unique genomic positions, compared with camptothecin. The compound also induces protein-linked DNA breaks and Top1–DNA cleavage complexes that persist longer after compound removal than camptothecin. Concentration-dependent and persistent γH2AX formation was readily observed in cells treated with Genz-644282, and was present in greater than 50% of the cell population following 24 hours compound exposure. The compound shows partial cross-resistance in cell lines resistant to camptothecin. These cell lines include the human prostate DU145RC0.1 and the leukemic CEM/C2 cells. Limited cross-resistance to Genz-644282 was also found in the Top1 knockdown colon cancer (HCT116) and breast cancer (MCF7) cell lines and in human adenocarcinoma cells (KB31/KBV1) that overexpress (P-glycoprotein, ABCB1), a member of the ATP-binding cassette family of cell surface transport proteins known to confer MDR. Together, our results provide the first molecular and cellular characterization of Genz-644282 and its clinically relevant metabolites. Mol Cancer Ther; 10(8); 1490–9. ©2011 AACR.
Data from Trabectedin and Its C Subunit Modified Analogue PM01183 Attenuate Nucleotide Excision Repair and Show Activity toward Platinum-Resistant Cells
Authors: Soares Daniele G. , Machado Miriana S. , Rocca Céline J. , Poindessous Virginie , Ouaret Djamila , Sarasin Alain , Galmarini Carlos M. , Henriques João A.P. , Escargueil Alexandre E. , Larsen Annette K.
Published: March 2024

Abstract
PM01183 is a novel marine-derived covalent DNA binder in clinical development. PM01183 is structurally similar to trabectedin (yondelis, ecteinascidin-743) except for the C subunit, and this modification is accompanied by different pharmacokinetics in cancer patients. We here characterize the interaction of PM01183 with the nucleotide excision repair (NER) pathway in comparison with trabectedin. Our results show for the first time that although neither PM01183 nor trabectedin is repaired by NER, both compounds are able to interfere with the NER machinery thereby attenuating the repair of specific NER substrates. We further show that the NER activity is increased in 3 of 4 cellular models with acquired resistance to cisplatin or oxaliplatin, confirming the involvement of NER in the resistance to platinum derivatives. Importantly, both PM01183 and trabectedin show unchanged or even enhanced activity toward all 4 cisplatin- and oxaliplatin-resistant cell lines. We finally show that combinations of PM01183 and cisplatin were mostly synergistic toward both parental and cisplatin-resistant ovarian carcinoma cells as indicated by Chou and Talalay analysis. These data show that the C subunit of trabectedin can be subjected to at least some structural modifications without loss of activity or NER interaction. While PM01183 and trabectedin appear functionally similar in cellular models, it is likely that the differences in pharmacokinetics may allow different dosing and scheduling of PM01183 in the clinic that could lead to novel and/or increased antitumor activity. Taken together, our results provide a mechanistic basis to support clinical trials of PM01183 alone or in combination with cisplatin. Mol Cancer Ther; 10(8); 1481–9. ©2011 AACR.
Data from Characterization of an Oxaliplatin Sensitivity Predictor in a Preclinical Murine Model of Colorectal Cancer
Authors: Kim Mickey K. , Osada Takuya , Barry William T. , Yang Xiao Yi , Freedman Jennifer A. , Tsamis Katherine A. , Datto Michael , Clary Bryan M. , Clay Timothy , Morse Michael A. , Febbo Philip G. , Lyerly H. Kim , Hsu David S.
Published: March 2024

Abstract
Despite advances in contemporary chemotherapeutic strategies, long-term survival still remains elusive for patients with metastatic colorectal cancer. A better understanding of the molecular markers of drug sensitivity to match therapy with patient is needed to improve clinical outcomes. In this study, we used in vitro drug sensitivity data from the NCI-60 cell lines together with their Affymetrix microarray data to develop a gene expression signature to predict sensitivity to oxaliplatin. To validate our oxaliplatin sensitivity signature, patient-derived colorectal cancer explants (PDCCE) were developed in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice from resected human colorectal tumors. Analysis of gene expression profiles found similarities between the PDCCEs and their parental human tumors, suggesting their utility to study drug sensitivity in vivo. The oxaliplatin sensitivity signature was then validated in vivo with response data from 14 PDCCEs treated with oxaliplatin and was found to have an accuracy of 92.9% (sensitivity = 87.5%; specificity = 100%). Our findings suggest that PDCCEs can be a novel source to study drug sensitivity in colorectal cancer. Furthermore, genomic-based analysis has the potential to be incorporated into future strategies to optimize individual therapy for patients with metastatic colorectal cancer. Mol Cancer Ther; 11(7); 1500–9. ©2012 AACR.
Data from Acquisition of Resistance toward HYD1 Correlates with a Reduction in Cleaved α4 Integrin Expression and a Compromised CAM-DR Phenotype
Authors: Emmons Michael F. , Gebhard Anthony W. , Nair Rajesh R. , Baz Rachid , McLaughlin Mark L. , Cress Anne E. , Hazlehurst Lori A.
Published: March 2024

Abstract
We recently reported that the β1 integrin antagonist, referred to as HYD1, induces necrotic cell death in myeloma cell lines as a single agent using in vitro and in vivo models. In this article, we sought to delineate the determinants of sensitivity and resistance toward HYD1-induced cell death. To this end, we developed an HYD1 isogenic resistant myeloma cell line by chronically exposing H929 myeloma cells to increasing concentrations of HYD1. Our data indicate that the acquisition of resistance toward HYD1 correlates with reduced levels of the cleaved α4 integrin subunit. Consistent with reduced VLA-4 (α4β1) expression, the resistant variant showed ablated functional binding to fibronectin, VCAM-1, and the bone marrow stroma cell line HS-5. The reduction in binding of the resistant cell line to HS-5 cells translated to a compromised cell adhesion-mediated drug resistant phenotype as shown by increased sensitivity to melphalan- and bortezomib-induced cell death in the bone marrow stroma coculture model of drug resistance. Importantly, we show that HYD1 is more potent in relapsed myeloma specimens than newly diagnosed patients, a finding that correlated with α4 integrin expression. Collectively, these data indicate that this novel d-amino acid peptide may represent a good candidate for pursuing clinical trials in relapsed myeloma and in particular patients with high levels of α4 integrin. Moreover, our data provide further rationale for continued preclinical development of HYD1 and analogues of HYD1 for the treatment of multiple myeloma and potentially other tumors that home and/or metastasize to the bone. Mol Cancer Ther; 10(12); 2257–66. ©2011 AACR.
Data from Phenotypic Reversion of Invasive Neurofibromin-Deficient Schwannoma by FTS: Ras Inhibition Reduces BMP4/Erk/Smad Signaling
Authors: Barkan Batya , Kloog Yoel , Ehrlich Marcelo
Published: March 2024

Abstract
Neurofibromin-deficient (Nf1−/−) malignant peripheral nerve sheath tumors (MPNST) are highly invasive, refractory to chemotherapy, and characterized by overactivated Ras. Ras activates mitogenic pathways and regulates morphogenic programs—such as those induced by bone morphogenetic proteins (BMP) and TGF-β. The role of such a cross-talk in determining the phenotype and transformation potential of MPNSTs is unknown. Here, we used MPNST cell lines and selective Ras inhibition with S-trans,trans-farnesylthiosalicylic-acid (FTS; salirasib) in conjunction with specific inhibitors of TGF-β and BMP signaling. FTS perturbed signaling of BMP4 and TGF-β1 to Smad-dependent and Erk-dependent pathways. Furthermore, FTS inhibited motility and spreading, reduced the gelatinase secretion, eliminated the expression and activation of regulators of cell–matrix interaction, and altered gene expression. These phenomena are indicative of a phenotypic reversion of NF1-defficient cells by FTS. Inhibition of BMP4 and TGF-β by noggin and SB-431542, respectively, mimicked the FTS-mediated effects on adhesion, spreading, and cell morphology. This strongly suggests that a cross-talk among TGF-β superfamily ligands and Ras plays a significant role in the transformation of NF1−/− MPNSTs. Our results support the therapeutic potential of FTS, in conjuncture with BMP and TGF-β pathway inhibitors, toward the inhibition of mitogenic and morphogenic signaling pathways and the alleviation of NF1 symptoms. Mol Cancer Ther; 10(8); 1317–26. ©2011 AACR.
Data from Novel Irreversible Small Molecule Inhibitors of Replication Protein A Display Single-Agent Activity and Synergize with Cisplatin
Authors: Neher Tracy M. , Bodenmiller Diane , Fitch Richard W. , Jalal Shadia I. , Turchi John J.
Published: March 2024

Abstract
Replication protein A (RPA) is a single-strand DNA-binding protein with essential roles in DNA replication, recombination, and repair. It is necessary for the formation of the preincision complex that is required for proper incision of damaged DNA nucleotides during DNA repair. We have previously identified small molecule inhibitors (SMI) with the ability to disrupt RPA-binding activity to ssDNA. Further characterization of these RPA inhibitors was done using both lung and ovarian cancer cell lines. Lung cancer cell lines showed increased apoptotic cell death following treatment with the SMI MCI13E, with IC50 values of approximately 5 μmol/L. The ovarian cancer cell line A2780 and the p53-null lung cancer cell line H1299 were particularly sensitive to MCI13E treatment, with IC50 values less than 3 μmol/L. Furthermore, a cell-cycle effect was observed in lung cancer cell lines that resulted in a lengthening of either G1 or S-phases of the cell cycle following single-agent treatment. Sequential treatment with MCI13E and cisplatin resulted in synergism. Overall, these data suggest that decreasing DNA-binding activity of RPA via a SMI may disrupt the role of RPA in cell-cycle regulation. Thus, SMIs of RPA hold the potential to be used as single-agent chemotherapeutics or in combination with current chemotherapeutic regimens to increase efficacy. Mol Cancer Ther; 10(10); 1796–806. ©2011 AACR.
Data from Antitumor Activity of the Hsp90 Inhibitor IPI-504 in HER2-Positive Trastuzumab-Resistant Breast Cancer
Authors: Scaltriti Maurizio , Serra Violeta , Normant Emmanuel , Guzman Marta , Rodriguez Olga , Lim Alice R. , Slocum Kelly L. , West Kip A. , Rodriguez Varenka , Prudkin Ludmila , Jimenez José , Aura Claudia , Baselga José
Published: March 2024

Abstract
Hsp90 facilitates the maturation and stability of numerous oncoproteins, including HER2. The aim of this study was to assess the antitumor activity of the Hsp90 inhibitor IPI-504 in trastuzumab-resistant, HER2-overexpressing breast cancer cells. Therapy with trastuzumab, IPI-504, and the combination of trastuzumab and IPI-504 was evaluated in trastuzumab-sensitive and trastuzumab-resistant cells. Inhibition of protein targets, cell proliferation, and tumor growth was assessed in vitro and in xenograft models. IPI-504 inhibited proliferation of both trastuzumab-sensitive and trastuzumab-resistant cells. Administration of IPI-504 markedly reduced total levels of HER2 and Akt, as well as phosphorylated Akt and mitogen-activated protein kinase (MAPK), to an equal extent in trastuzumab-sensitive and trastuzumab-resistant cells. IPI-504, used as single agent or in combination with trastuzumab, also inhibited in vivo the growth of both trastuzumab-sensitive and -resistant tumor xenografts. As a mechanism for the observed antitumor activity, IPI-504 resulted in a marked decrease in the levels of HER2, Akt, p-Akt, and p-MAPK in trastuzumab-resistant xenografts as early as 12 hours after a single dose of IPI-504. IPI-504–mediated Hsp90 inhibition may represent a novel therapeutic approach in trastuzumab refractory HER2-positive breast cancer. Mol Cancer Ther; 10(5); 817–24. ©2011 AACR.
Data from Inhibition of PARP-1 by Olaparib (AZD2281) Increases the Radiosensitivity of a Lung Tumor Xenograft
Authors: Senra Joana M. , Telfer Brian A. , Cherry Kim E. , McCrudden Cian M. , Hirst David G. , O'Connor Mark J. , Wedge Stephen R. , Stratford Ian J.
Published: March 2024

Abstract
PARP-1 is a critical enzyme in the repair of DNA strand breaks. Inhibition of PARP-1 increases the effectiveness of radiation in killing tumor cells. However, although the mechanism(s) are well understood for these radiosensitizing effects in vitro, the underlying mechanism(s) in vivo are less clear. Nicotinamide, a drug structurally related to the first generation PARP-1 inhibitor, 3-aminobenzamide, reduces tumor hypoxia by preventing transient cessations in tumor blood flow, thus improving tumor oxygenation and sensitivity to radiotherapy. Here, we investigate whether olaparib, a potent PARP-1 inhibitor, enhances radiotherapy, not only by inhibiting DNA repair but also by changing tumor vascular hemodynamics in non–small cell lung carcinoma (NSCLC). In irradiated Calu-6 and A549 cells, olaparib enhanced the cytotoxic effects of radiation (sensitizer enhancement ratio at 10% survival = 1.5 and 1.3) and DNA double-strand breaks persisted for at least 24 hours after treatment. Combination treatment of Calu-6 xenografts with olaparib and fractionated radiotherapy caused significant tumor regression (P = 0.007) relative to radiotherapy alone. To determine whether this radiosensitization was solely due to effects on DNA repair, we used a dorsal window chamber model to establish the drug/radiation effects on vessel dynamics. Olaparib alone, when given as single or multiple daily doses, or in combination with fractionated radiotherapy, increased the perfusion of tumor blood vessels. Furthermore, an ex vivo assay in phenylephrine preconstricted arteries confirmed olaparib to have higher vasodilatory properties than nicotinamide. This study suggests that olaparib warrants consideration for further development in combination with radiotherapy in clinical oncology settings such as NSCLC. Mol Cancer Ther; 10(10); 1949–58. ©2011 AACR.
Data from Characterization of the Cellular and Antitumor Effects of MPI-0479605, a Small-Molecule Inhibitor of the Mitotic Kinase Mps1
Authors: Tardif Keith D. , Rogers Aaron , Cassiano Jared , Roth Bruce L. , Cimbora Daniel M. , McKinnon Rena , Peterson Ashley , Douce Thomas B. , Robinson Rosann , Dorweiler Irene , Davis Thaylon , Hess Mark A. , Ostanin Kirill , Papac Damon I. , Baichwal Vijay , McAlexander Ian , Willardsen J. Adam , Saunders Michael , Christophe Hoarau , Kumar D. Vijay , Wettstein Daniel A. , Carlson Robert O. , Williams Brandi L.
Published: March 2024

Abstract
Mps1 is a dual specificity protein kinase that is essential for the bipolar attachment of chromosomes to the mitotic spindle and for maintaining the spindle assembly checkpoint until all chromosomes are properly attached. Mps1 is expressed at high levels during mitosis and is abundantly expressed in cancer cells. Disruption of Mps1 function induces aneuploidy and cell death. We report the identification of MPI-0479605, a potent and selective ATP competitive inhibitor of Mps1. Cells treated with MPI-0479605 undergo aberrant mitosis, resulting in aneuploidy and formation of micronuclei. In cells with wild-type p53, this promotes the induction of a postmitotic checkpoint characterized by the ATM- and RAD3-related-dependent activation of the p53–p21 pathway. In both wild-type and p53 mutant cells lines, there is a growth arrest and inhibition of DNA synthesis. Subsequently, cells undergo mitotic catastrophe and/or an apoptotic response. In xenograft models, MPI-0479605 inhibits tumor growth, suggesting that drugs targeting Mps1 may have utility as novel cancer therapeutics. Mol Cancer Ther; 10(12); 2267–75. ©2011 AACR.
Data from NF-κB Is Required for Smac Mimetic-Mediated Sensitization of Glioblastoma Cells for γ-Irradiation–Induced Apoptosis
Authors: Berger Rebecca , Jennewein Claudia , Marschall Viola , Karl Sabine , Cristofanon Silvia , Wagner Liane , Vellanki Sri HariKrishna , Hehlgans Stephanie , Rödel Franz , Debatin Klaus-Michael , Ludolph Albert C. , Fulda Simone
Published: March 2024

Abstract
Evasion of apoptosis contributes to radioresistance of glioblastoma, calling for novel strategies to overcome apoptosis resistance. In this study, we investigated the potential of the small molecule Smac mimetic BV6 to modulate radiosensitivity of glioblastoma cells. Here, we identify a novel proapoptotic function of NF-κB in γ-irradiation–induced apoptosis of glioblastoma cells by showing, for the first time, that NF-κB is critically required for Smac mimetic–mediated radiosensitization. BV6 significantly increases γ-irradiation–triggered apoptosis in several glioblastoma cell lines in a dose- and time-dependent manner. Calculation of combination index (CI) reveals that the interaction of BV6 and γ-irradiation is highly synergistic (CI < 0.3). Molecular studies show that BV6 stimulates NF-κB activation, which is critical for radiosensitization, because genetic inhibition of NF-κB by overexpression of the dominant-negative superrepressor IκBα-SR significantly decreases BV6- and γ-irradiation–induced apoptosis. Also, the BV6-mediated enhancement of γ-irradiation–triggered caspase activation, drop of mitochondrial membrane potential, and cytochrome c release is abolished in cells overexpressing IκBα-SR. Similarly, NF-κB inhibition by ectopic expression of a kinase dead mutant of IKKβ prevents the BV6-mediated sensitization for γ-irradiation. The clinical relevance is underscored by experiments with primary tumor samples showing that BV6 sensitizes primary cultured glioma cells as well as glioblastoma-initiating cancer stem cells derived from surgical specimens for γ-irradiation. In conclusion, we identify NF-κB as a critical mediator of Smac mimetic-conferred radiosensitization of glioblastoma cells. These results have important implications for the development of Smac mimetic–based combination protocols for radiosensitization of glioblastoma. Mol Cancer Ther; 10(10); 1867–75. ©2011 AACR.
Data from Chromatin Structure Predicts Epigenetic Therapy Responsiveness in Sarcoma
Authors: Mills Joslyn , Hricik Todd , Siddiqi Sara , Matushansky Igor
Published: March 2024

Abstract
To formally explore the potential therapeutic effect of histone deacetylase inhibitors (HDACI) and DNA-methyltransferase inhibitors (DNA-MI) on sarcomas, we treated a large sarcoma cell line panel with five different HDACIs in the absence and presence of the DNA-MI decitabine. We observed that the IC50 value of each HDACI was consistent for all cell lines whereas decitabine as a single agent showed no growth inhibition at standard doses. Combination HDACI/DNA-MI therapy showed a preferential synergism for specific sarcoma cell lines. Subsequently, we identified and validated (in vitro and in vivo) a two-gene set signature (high CUGBP2; low RHOJ) that associated with the synergistic phenotype. We further uncover that the epigenetic synergism leading to specific upregulation of CDKI p21 in specific cell lines is a function of the differences in the degree of baseline chromatin modification. Finally, we show that these chromatin and gene expression patterns are similarly present in the majority of high-grade primary sarcomas. Our results provide the first demonstration of a gene set that can predict responsiveness to HDACI/DNA-MI and links this responsiveness mechanistically to the baseline chromatin structure. Mol Cancer Ther; 10(2); 313–24. ©2011 AACR.
Data from Potent Inhibition of Angiogenesis by the IGF-1 Receptor-Targeting Antibody SCH717454 Is Reversed by IGF-2
Authors: Bid Hemant K. , Zhan Jun , Phelps Doris A. , Kurmasheva Raushan T. , Houghton Peter J.
Published: March 2024

Abstract
Previously, we reported that a predominant action of a type-1 insulin-like growth factor receptor (IGF-1R)-targeted antibody was through inhibiting tumor-derived VEGF, and indirectly, angiogenesis. Here, we examined the direct antiangiogenic activity of the IGF-1R-targeted antibody SCH717454 that inhibits ligand-receptor binding and the mechanism by which tumors circumvent its antiangiogenic activity. Inhibition of ligand-stimulated activation of IGF-1R, insulin receptor (IN-R), or downstream signaling [phosphorylation of Akt (Ser473)] was determined by receptor-specific immunoprecipitation and immunoblotting. Inhibition of angiogenesis was determined by proliferation and tube formation using human umbilical vein endothelial cells (HUVEC) in vitro and in Matrigel plugs implanted in mice. SCH717454 blocked IGF-1-stimulated but not IGF-2-stimulated phosphorylation of Akt in sarcoma cells. Immunoprecipitation using anti-IGF-1R and anti-IN-R antibodies revealed that SCH717454 equally blocked IGF-1-stimulated and IGF-2-stimulated IGF-1R phosphorylation, but not IGF-2-stimulated phosphorylation of IN-R. SCH717454 completely blocked VEGF-stimulated proliferation and tube formation of HUVECs, but exogenous IGF-2 and insulin circumvented these inhibitory effects. Coculture of HUVECs with IGF-2-secreting tumor cells completely abrogated SCH717454 inhibition of VEGF-stimulated HUVEC tube formation. In mice, SCH717454 inhibited angiogenesis in VEGF-infused Matrigel plugs, but had no inhibitory activity when plugs contained both VEGF + IGF-2. These results reveal for the first time, a role for IGF-1R signaling in VEGF-mediated angiogenesis in vitro and indicate direct antiangiogenic activity of SCH717454. Both in vitro and in vivo IGF-2 circumvented these effects through IN-R signaling. Many childhood cancers secrete IGF-2, suggesting that tumor-derived IGF-2 in the microenvironment maintains angiogenesis in the presence of IGF-1R-targeted antibodies allowing tumor progression. Mol Cancer Ther; 11(3); 649–59. ©2011 AACR.
Data from Inhibition of Mutant GNAQ Signaling in Uveal Melanoma Induces AMPK-Dependent Autophagic Cell Death
Authors: Ambrosini Grazia , Musi Elgilda , Ho Alan L. , de Stanchina Elisa , Schwartz Gary K.
Published: March 2024

Abstract
Oncogenic mutations in GNAQ and GNA11 genes are found in 80% of uveal melanoma. These mutations result in the activation of the RAF/MEK signaling pathway culminating in the stimulation of ERK1/2 mitogen-activated protein kinases. In this study, using a siRNA strategy, we show that mutant GNAQ signals to both MEK and AKT, and that combined inhibition of these pathways with the MEK inhibitor selumetinib (AZD6244) and the AKT inhibitor MK2206 induced a synergistic decrease in cell viability. This effect was genotype dependent as autophagic markers like beclin1 and LC3 were induced in GNAQ-mutant cells, whereas apoptosis was the mechanism of cell death of BRAF-mutant cells, and cells without either mutation underwent cell-cycle arrest. The inhibition of MEK/ATK pathways induced activation of AMP-activated protein kinase (AMPK) in the GNAQ-mutant cells. The downregulation of AMPK by siRNA or its inhibition with compound C did not rescue the cells from autophagy, rather they died by apoptosis, defining AMPK as a key regulator of mutant GNAQ signaling and a switch between autophagy and apoptosis. Furthermore, this combination treatment was effective in inhibiting tumor growth in xenograft mouse models. These findings suggest that inhibition of MEK and AKT may represent a promising approach for targeted therapy of patients with uveal melanoma. Mol Cancer Ther; 12(5); 768–76. ©2013 AACR.
Data from Tumor Suppressor MicroRNA-493 Decreases Cell Motility and Migration Ability in Human Bladder Cancer Cells by Downregulating RhoC and FZD4
Authors: Ueno Koji , Hirata Hiroshi , Majid Shahana , Yamamura Soichiro , Shahryari Varahram , Tabatabai Z. Laura , Hinoda Yuji , Dahiya Rajvir
Published: March 2024

Abstract
The purpose of this study was to identify new tumor suppressor microRNAs (miRNA; miR) in bladder cancer, conduct functional analysis of their suppressive role, and identify their specific target genes. To explore tumor suppressor miRs in bladder cancer, miR microarray was conducted using SV-HUC-1, T24, J82, and TCCSUP cells. Expression of miR-493 in bladder cancer (T24, J82, and TCCSUP) cells was downregulated compared with normal SV-HUC-1 cells. Also, the expression of miR-493 was significantly lower in bladder cancer tissues than in their corresponding noncancerous tissues. Transfection of miR-493 into T24 or J82 cells decreased their cell growth and migration abilities. On the basis of this result, to identify potential miR-493 target genes, we used target scan algorithms to identify target oncogenes related to invasion and migration. miR-493 decreased 3′-untranslated region luciferase activity and protein expression of FZD4 and RhoC. miR-493 also decreased binding of RhoC and Rock-1. miR-493 is a new tumor suppressor miRNA in bladder cancer and inhibits cell motility through downregulation of RhoC and FZD4. Mol Cancer Ther; 11(1); 244–53. ©2011 AACR.
Data from Inhibition of p38 MAPK-Dependent Excision Repair Cross-Complementing 1 Expression Decreases the DNA Repair Capacity to Sensitize Lung Cancer Cells to Etoposide
Authors: Tsai Min-Shao , Weng Shao-Hsing , Chen Huang-Jen , Chiu Yu-Fan , Huang Yu-Ching , Tseng Sheng-Chieh , Kuo Ya-Hsun , Lin Yun-Wei
Published: March 2024

Abstract
Etoposide (VP-16), a topoisomerase II inhibitor, is an effective anticancer drug currently used for the treatment of a wide range of cancers. Excision repair cross-complementary 1 (ERCC1) is a key protein involved in the process of nucleotide excision repair. High level of ERCC1 expression in cancers is associated with resistance to DNA damage-based chemotherapy. In this study, the effects of p38 mitogen-activated protein kinase (MAPK) signal on the ERCC1 expression induced by etoposide in non–small cell lung cancer (NSCLC) cell lines was investigated. Etoposide increased phosphorylated MAPK kinase 3/6 (MKK3/6)-p38 MAPK and ERCC1 protein and mRNA levels in A549 and H1975 cells. Moreover, SB202190, a p38 inhibitor, or knockdown of p38 expression by specific short interfering RNA (siRNA) significantly decreased the etoposide-induced ERCC1 protein levels and DNA repair capacity in etoposide-exposed NSCLC cells. Enhancement of p38 activation by constitutively active MKK6 (MKK6E) increased ERCC1 protein levels. Specific inhibition of ERCC1 by siRNA significantly enhanced the etoposide-induced cytotoxicity and hypoxanthine guanine phosphoribosyltransferase (hprt) gene mutation rate. Moreover, the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) could decrease the etoposide-induced p38 MAPK-mediated ERCC1 expression and augment the cytotoxic effect and growth inhibition by etopsoside. 17-AAG and etoposide-induced synergistic cytotoxic effect and DNA repair capacity decrease could be abrogated in lung cancer cells with MKK6E or HA-p38 MAPK expression vector transfection. Our results suggest that in human NSCLC cells, ERCC1 is induced by etoposide through the p38 MAPK pathway, and this phenomenon is required for NSCLC survival and resistant DNA damage. Mol Cancer Ther; 11(3); 561–71. ©2011 AACR.
Data from Antitumor Mechanisms of Targeting the PDK1 Pathway in Head and Neck Cancer
Authors: Bhola Neil E. , Freilino Maria L. , Joyce Sonali C. , Sen Malabika , Thomas Sufi M. , Sahu Anirban , Cassell Andre , Chen Ching-Shih , Grandis Jennifer R.
Published: March 2024

Abstract
G-protein–coupled receptors (GPCR) activate the epidermal growth factor receptor (EGFR) and mediate EGFR-independent signaling pathways to promote the growth of a variety of cancers, including head and neck squamous cell carcinoma (HNSCC). Identification of the common signaling mechanisms involved in GPCR-induced EGFR-dependent and EGFR-independent processes will facilitate the development of more therapeutic strategies. In this study, we hypothesized that phosphoinositide-dependent kinase 1 (PDK1) contributes to GPCR–EGFR cross-talk and signaling in the absence of EGFR and suggests that inhibition of the PDK1 pathway may be effective in the treatment of HNSCC. The contribution of PDK1 to the EGFR-dependent and EGFR-independent signaling in HNSCC was determined using RNA interference, a kinase-dead mutant, and pharmacologic inhibition. In vivo xenografts studies were also carried out to determine the efficacy of targeting PDK1 alone or in combination with the U.S. Food and Drug Administration–approved EGFR inhibitor cetuximab. PDK1 contributed to both GPCR-induced EGFR activation and cell growth. PDK1 also mediated activation of p70S6K in the absence of EGFR. Blockade of PDK1 with a small molecule inhibitor (AR-12) abrogated HNSCC growth, induced apoptosis, and enhanced the antiproliferative effects of EGFR tyrosine kinase inhibitors in vitro. HNSCC xenografts expressing kinase-dead PDK1 showed increased sensitivity to cetuximab compared with vector-transfected controls. Administration of AR-12 substantially decreased HNSCC tumor growth in vivo. These cumulative results show that PDK1 is a common signaling intermediate in GPCR–EGFR cross-talk and EGFR-independent signaling, and in which targeting the PDK1 pathway may represent a rational therapeutic strategy to enhance clinical responses to EGFR inhibitors in HNSCC. Mol Cancer Ther; 11(6); 1236–46. ©2012 AACR.
Data from Combining PARP-1 Inhibition and Radiation in Ewing Sarcoma Results in Lethal DNA Damage
Authors: Lee Hae-June , Yoon Changhwan , Schmidt Benjamin , Park Do Joong , Zhang Alexia Y. , Erkizan Hayriye V. , Toretsky Jeffrey A. , Kirsch David G. , Yoon Sam S.
Published: March 2024

Abstract
Ewing sarcomas (ES) harbor a chromosomal translocation that fuses the EWS gene to an ETS transcription factor, most commonly Friend leukemia integration 1 (FLI1). The EWS-FLI1 fusion protein acts in a positive feedback loop to maintain the expression of PARP-1, which is involved in repair of DNA damage. Here, we examine the effects of PARP-1 inhibition and radiation therapy on Ewing sarcomas. In proliferation assays, the Ewing sarcoma cell lines RD-ES and SK-N-MC were much more sensitive than non-Ewing sarcoma cell lines to the PARP-1 inhibitor olaparib (Ola; IC50 0.5–1 μmol/L vs. >5 μmol/L) and to radiation (IC50 2–4 Gy vs. >6 Gy). PARP-1 inhibition with short hairpin RNA (shRNA) or Ola sensitized Ewing sarcoma cells, but not non-Ewing sarcoma cells, to radiation therapy in both proliferation and colony formation assays. Using the Comet assay, radiation of Ewing sarcoma cells with Ola, compared to without Ola, resulted in more DNA damage at 1 hour (mean tail moment 36–54 vs. 26–28) and sustained DNA damage at 24 hours (24–29 vs. 6–8). This DNA damage led to a 2.9- to 4.0-fold increase in apoptosis and a 1.6- to 2.4-fold increase in cell death. The effect of PARP-1 inhibition and radiation therapy on Ewing sarcoma cells was lost when EWS-FLI1 was silenced by shRNA. A small dose of radiation therapy (4 Gy), when combined with PARP-1 inhibition, stopped the growth of SK-N-MC flank tumors xenografts. In conclusion, PARP-1 inhibition in Ewing sarcomas amplifies the level and duration of DNA damage caused by radiation therapy, leading to synergistic increases in apoptosis and cell death in a EWS-FLI1–dependent manner. Mol Cancer Ther; 12(11); 2591–600. ©2013 AACR.
Data from Autophagy Inhibition Synergistically Enhances Anticancer Efficacy of RAMBA, VN/12-1 in SKBR-3 Cells, and Tumor Xenografts
Authors: Godbole Abhijit M. , Purushottamachar Puranik , Martin Marlena S. , Daskalakis Constantine , Njar Vincent C.O.
Published: March 2024

Abstract
VN/12-1 is a novel retinoic acid metabolism blocking agent discovered in our laboratory. The purpose of the study was to elucidate the molecular mechanism of anticancer activity of VN/12-1 in breast cancer cell lines and in tumor xenografts. We investigated the effects of VN/12-1 on induction of autophagy and apoptosis in SKBR-3 cells. Furthermore, we also examined the impact of pharmacologic and genomic inhibition of autophagy on anticancer activity of VN/12-1. Finally, the antitumor activity of VN/12-1 was evaluated as a single agent and in combination with autophagy inhibitor chloroquine in an SKBR-3 mouse xenograft model. Short exposure of low dose (<10 μmol/L) of VN/12-1 induced endoplasmic reticulum stress, autophagy, and inhibited G1–S phase transition and caused a protective response. However, a higher dose of VN/12-1 initiated apoptosis in vitro. Inhibition of autophagy using either pharmacologic inhibitors or RNA interference of Beclin-1 enhanced anticancer activity induced by VN/12-1 in SKBR-3 cells by triggering apoptosis. Importantly, VN/12-1 (5 mg/kg twice weekly) and the combination of VN/12-1 (5 mg/kg twice weekly) + chloroquine (50 mg/kg twice weekly) significantly suppressed established SKBR-3 tumor growth by 81.4% (P < 0.001 vs. control) and 96.2% (P < 0.001 vs. control), respectively. Our novel findings suggest that VN/12-1 may be useful as a single agent or in combination with autophagy inhibitors for treating human breast cancers. Our data provides a strong rationale for clinical evaluation of VN/12-1 as single agent or in combination with autophagy inhibitors. Mol Cancer Ther; 11(4); 898–908. ©2012 AACR.
Data from Smoking Induces Epithelial-to-Mesenchymal Transition in Non–Small Cell Lung Cancer through HDAC-Mediated Downregulation of E-Cadherin
Authors: Nagathihalli Nagaraj S. , Massion Pierre P. , Gonzalez Adriana L. , Lu Pengcheng , Datta Pran K.
Published: March 2024

Abstract
Epidemiological studies have shown that most cases of lung cancers (85%–90%) are directly attributable to tobacco smoking. Although association between cigarette smoking and lung cancer is well documented, surprisingly little is known about the molecular mechanisms of how smoking is involved in epithelial-to-mesenchymal transition (EMT) through epigenetic changes. Here, we show that lung cancer patients with a smoking history have low E-cadherin levels and loss of E-cadherin is a poor prognostic factor in smokers. Moreover, the downregulation of E-cadherin correlates with the number of pack years. In an attempt to determine the role of long-term cigarette smoking on EMT, we observed that treatment of lung cell lines with cigarette smoke condensate (CSC) induces EMT through downregulation of epithelial markers, including E-cadherin and upregulation of mesenchymal markers. CSC decreases E-cadherin expression at the transcriptional level through upregulation of LEF1 and Slug, and knockdown of these two proteins increases E-cadherin expression. Importantly, chromatin immunoprecipitation assays suggest that LEF-1 and Slug binding to E-cadherin promoter is important for CSC-mediated downregulation of E-cadherin. The histone deacetylase (HDAC) inhibitor MS-275 reverses CSC-induced EMT, migration, and invasion through the restoration of E-cadherin expression. These results suggest that recruitment of HDACs by transcriptional repressors LEF-1 and Slug is responsible for E-cadherin suppression and EMT in cigarette smokers and provide a potential drug target toward the treatment of lung cancer. Mol Cancer Ther; 11(11); 2362–72. ©2012 AACR.
Data from Inhibition of ATR-Dependent Signaling by Protoapigenone and Its Derivative Sensitizes Cancer Cells to Interstrand Cross-link–Generating Agents In Vitro and In Vivo
Authors: Wang Hui-Chun , Lee Alan Yueh-Luen , Chou Wen-Cheng , Wu Chin-Chung , Tseng Chao-Neng , Liu Kevin Yen-Ting , Lin Wen-Lien , Chang Fang-Rong , Chuang Da-Wei , Hunyadi Attila , Wu Yang-Chang
Published: March 2024

Abstract
DNA damage caused during cancer treatment can rapidly activate the ataxia telangiectasia-mutated (ATM) and ATM and Rad3-related (ATR)-dependent phosphorylation of Chk2 and Chk1 kinases, which are hallmarks of the DNA damage response (DDR). Pharmacologic inhibition of ATR causes a synthetic lethal effect on ATM- or p53-defective cancers, suggesting that such inhibition is an effective way to improve the sensitivity of cancers to DNA-damaging agents. Here, both the natural compound protoapigenone (WYC02) and its synthetic derivative WYC0209 exhibited cytotoxic effects on various cancer cell lines. WYC02 causes chromosomal aberration in the mitotic spreads of Chinese hamster ovary cells. Interestingly, cancer cells did not exhibit typical DDR markers upon exposure to WYC02 and WYC0209 (WYCs). Further investigation into the molecular mechanisms of WYCs function revealed that they have a potential ability to inhibit DDR, particularly on activation of Chk1 and Fanconi anemia group D2 protein (FANCD2), but not Chk2. In this way, WYCs inhibited ATR-mediated DNA damage checkpoint and repair. Furthermore, when combined with the DNA cross-linking agent cisplatin, treatment with WYCs resulted in increased tumor sensitivity to interstrand cross-link–generating agents both in vitro and in vivo. Our results therefore especially implicate WYCs in enhancing tumor chemosensitivity when the ATR checkpoint is constitutively active in states of oncogene-driven replicative stress or tolerance to DNA-interfering agents. Mol Cancer Ther; 11(7); 1443–53. ©2012 AACR.
Data from Induction of Endoplasmic Reticulum Stress by Sorafenib and Activation of NF-κB by Lestaurtinib as a Novel Resistance Mechanism in Hodgkin Lymphoma Cell Lines
Authors: Holz Meike Stefanie , Janning Angela , Renné Christoph , Gattenlöhner Stefan , Spieker Tilmann , Bräuninger Andreas
Published: March 2024

Abstract
Hodgkin-Reed/Sternberg (HRS) cells of classical Hodgkin lymphoma show aberrant expression and activation of several receptor tyrosine kinases (RTK) in the majority of cases. Therefore, we tested whether tyrosine kinase inhibitors (TKI) already in clinical use or late stages of clinical trials have antiproliferative effects on HRS cell lines and evaluated the targets, affected signaling pathways, and mechanisms of cell death and resistance. Sorafenib and lestaurtinib had antiproliferative effects on HRS cell lines at concentrations achievable in patients. Sorafenib inhibited platelet-derived growth factor receptor (PDGFR) α, TRKA and RON, caused decreases in total and phosphorylated amounts of several signaling molecules, and provoked caspase-3–independent cell death, most likely due to endoplasmic reticulum stress as indicated by upregulation of GADD34 and GADD153 and phosphorylation of PERK. Lestaurtinib inhibited TRKA, PDGFRα, RON, and JAK2 and had only a cytostatic effect. Besides deactivation, lestaurtinib also caused activation of signaling pathways. It caused increases in CD30L and TRAIL expression, and CD30L/CD30 signaling likely led to the observed concomitant activation of extracellular signal–regulated kinase 1/2 and the alternative NF-κB pathway. These data disclose the possible use of sorafenib for the treatment of Hodgkin lymphoma and highlight NF-κB activation as a potential novel mechanism of resistance toward TKIs. Mol Cancer Ther; 12(2); 173–83. ©2012 AACR.
Data from A 71-Gene Signature of TRAIL Sensitivity in Cancer Cells
Authors: Chen Jun-Jie , Knudsen Steen , Mazin Wiktor , Dahlgaard Jesper , Zhang Baolin
Published: March 2024

Abstract
TNF-related apoptosis inducing ligand (TRAIL) is a promising anticancer agent because of its ability to selectively induce apoptosis in cancer cells but not in most normal cells. However, some cancer cells are resistant to TRAIL cytotoxicity thereby limiting its therapeutic efficacy. Using genome-wide mRNA expression profiles from the NCI60 panel and their differential sensitivities to TRAIL-induced apoptosis, we have identified 71 genes whose expression levels are systemically higher in TRAIL-sensitive cell lines than resistant lines. The elevated expression of the 71 genes was able to accurately predict TRAIL sensitivity in the NCI60 training set and two test sets consisting of a total of 95 human cancer cell lines. Interestingly, the 71-gene signature is dominated by two functionally related gene families—interferon (IFN)-induced genes and the MHC genes. Consistent with this result, treatment with IFN-γ augmented TRAIL-induced apoptosis. The 71-gene signature could be evaluated clinically for predicting tumor response to TRAIL-related therapies. Mol Cancer Ther; 11(1); 34–44. ©2011 AACR.
Data from Effects of Anti-VEGF on Pharmacokinetics, Biodistribution, and Tumor Penetration of Trastuzumab in a Preclinical Breast Cancer Model
Authors: Pastuskovas Cinthia V. , Mundo Eduardo E. , Williams Simon P. , Nayak Tapan K. , Ho Jason , Ulufatu Sheila , Clark Suzanna , Ross Sarajane , Cheng Eric , Parsons-Reponte Kathryn , Cain Gary , Van Hoy Marjie , Majidy Nicholas , Bheddah Sheila , dela Cruz Chuh Josefa , Kozak Katherine R. , Lewin-Koh Nicholas , Nauka Peter , Bumbaca Daniela , Sliwkowski Mark , Tibbitts Jay , Theil Frank-Peter , Fielder Paul J. , Khawli Leslie A. , Boswell C. Andrew
Published: March 2024

Abstract
Both human epidermal growth factor receptor 2 (HER-2/neu) and VEGF overexpression correlate with aggressive phenotypes and decreased survival among breast cancer patients. Concordantly, the combination of trastuzumab (anti-HER2) with bevacizumab (anti-VEGF) has shown promising results in preclinical xenograft studies and in clinical trials. However, despite the known antiangiogenic mechanism of anti-VEGF antibodies, relatively little is known about their effects on the pharmacokinetics and tissue distribution of other antibodies. This study aimed to measure the disposition properties, with a particular emphasis on tumor uptake, of trastuzumab in the presence or absence of anti-VEGF. Radiolabeled trastuzumab was administered alone or in combination with an anti-VEGF antibody to mice bearing HER2-expressing KPL-4 breast cancer xenografts. Biodistribution, autoradiography, and single-photon emission computed tomography–X-ray computed tomography imaging all showed that anti-VEGF administration reduced accumulation of trastuzumab in tumors despite comparable blood exposures and similar distributions in most other tissues. A similar trend was also observed for an isotype-matched IgG with no affinity for HER2, showing reduced vascular permeability to macromolecules. Reduced tumor blood flow (P < 0.05) was observed following anti-VEGF treatment, with no significant differences in the other physiologic parameters measured despite immunohistochemical evidence of reduced vascular density. In conclusion, anti-VEGF preadministration decreased tumor uptake of trastuzumab, and this phenomenon was mechanistically attributed to reduced vascular permeability and blood perfusion. These findings may ultimately help inform dosing strategies to achieve improved clinical outcomes. Mol Cancer Ther; 11(3); 752–62. ©2012 AACR.
Data from Attacking a Nexus of the Oncogenic Circuitry by Reversing Aberrant eIF4F-Mediated Translation
Authors: Bitterman Peter B. , Polunovsky Vitaly A.
Published: March 2024

Abstract
Notwithstanding their genetic complexity, different cancers share a core group of perturbed pathways converging upon a few regulatory nodes that link the intracellular-signaling network with the basic metabolic machinery. The clear implication of this view for cancer therapy is that instead of targeting individual genetic alterations one by one, the next generation of cancer therapeutics will target critical hubs in the cancer network. One such hub is the translation-initiation complex eIF4F, which integrates several cancer-related pathways into a self-amplifying signaling system. When hyperactivated by apical oncogenic signals, the eIF4F-driven translational apparatus selectively switches the translational repertoire of a cell toward malignancy. This central integrative role of pathologically activated eIF4F has motivated the development of small-molecule inhibitors to correct its function. A genome-wide, systems-level means to objectively evaluate the pharmacologic response to therapeutics targeting eIF4F remains an unmet challenge. Mol Cancer Ther; 11(5); 1051–61. ©2012 AACR.