bluuebunny/crossref_metadata_2025 huggingface dataset:
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: April 2023

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: April 2023

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 MEK/ERK Inhibitor U0126 Increases the Radiosensitivity of Rhabdomyosarcoma Cells In vitro and In vivo by Downregulating Growth and DNA Repair Signals
Authors: Marampon Francesco , Gravina Giovanni Luca , Di Rocco Agnese , Bonfili Pierluigi , Di Staso Mario , Fardella Caterina , Polidoro Lorella , Ciccarelli Carmela , Festuccia Claudio , Popov Vladimir M. , Pestell Richard G. , Tombolini Vincenzo , Zani Bianca Maria
Published: April 2023

Abstract
Multimodal treatment has improved the outcome of many solid tumors, and in some cases the use of radiosensitizers has significantly contributed to this gain. Activation of the extracellular signaling kinase pathway (MEK/ERK) generally results in stimulation of cell growth and confers a survival advantage playing the major role in human cancer. The potential involvement of this pathway in cellular radiosensitivity remains unclear. We previously reported that the disruption of c-Myc through MEK/ERK inhibition blocks the expression of the transformed phenotype; affects in vitro and in vivo growth and angiogenic signaling; and induces myogenic differentiation in the embryonal rhabdomyosarcoma (ERMS) cell lines (RD). This study was designed to examine whether the ERK pathway affects intrinsic radiosensitivity of rhabdomyosarcoma cancer cells. Exponentially growing human ERMS, RD, xenograft-derived RD-M1, and TE671 cell lines were used. The specific MEK/ERK inhibitor, U0126, reduced the clonogenic potential of the three cell lines, and was affected by radiation. U0126 inhibited phospho-active ERK1/2 and reduced DNA protein kinase catalytic subunit (DNA-PKcs) suggesting that ERKs and DNA-PKcs cooperate in radioprotection of rhabdomyosarcoma cells. The TE671 cell line xenotransplanted in mice showed a reduction in tumor mass and increase in the time of tumor progression with U0126 treatment associated with reduced DNA-PKcs, an effect enhanced by radiotherapy. Thus, our results show that MEK/ERK inhibition enhances radiosensitivity of rhabdomyosarcoma cells suggesting a rational approach in combination with radiotherapy. Mol Cancer Ther; 10(1); 159–68. ©2011 AACR.
Data from Obatoclax Interacts Synergistically with the Irreversible Proteasome Inhibitor Carfilzomib in GC- and ABC-DLBCL Cells In Vitro and In Vivo
Authors: Dasmahapatra Girija , Lembersky Dmitry , Son Minkyeong P. , Patel Hiral , Peterson Derick , Attkisson Elisa , Fisher Richard I. , Friedberg Jonathan W. , Dent Paul , Grant Steven
Published: April 2023

Abstract
Interactions between the irreversible proteasome inhibitor carfilzomib and the pan-BH3 mimetic obatoclax were examined in germinal center (GC)- and activated B-cell–diffuse large B-cell lymphoma (ABC-DLBCL) cells. Cotreatment with minimally toxic concentrations of carfilzomib (i.e., 2–6 nmol/L) and subtoxic concentrations of obatoclax (0.05–2.0 μmol/L) synergistically increased apoptosis in multiple DLBCL cell lines and increased lethality toward primary human DLBCL but not normal CD34+ cells. Synergistic interactions were associated with sharp increases in caspase-3 activation, PARP cleavage, p-JNK induction, upregulation of Noxa, and AKT dephosphorylation. Combined treatment also diminished carfilzomib-mediated Mcl-1 upregulation whereas immunoprecipitation analysis revealed reduced associations between Bak and Mcl-1/Bcl-xL and Bim and Mcl-1. The carfilzomib/obatoclax regimen triggered translocation, conformational change, and dimerization of Bax and activation of Bak. Genetic interruption of c-jun-NH2-kinase (JNK) and Noxa by short hairpin RNA knockdown, ectopic Mcl-1 expression, or enforced activation of AKT significantly attenuated carfilzomib/obatoclax-mediated apoptosis. Notably, coadministration of carfilzomib/obatoclax sharply increased apoptosis in multiple bortezomib-resistant DLBCL models. Finally, in vivo administration of carfilzomib and obatoclax to mice inoculated with SUDHL4 cells substantially suppressed tumor growth, activated JNK, inactivated AKT, and increased survival compared with the effects of single-agent treatment. Together, these findings argue that a strategy combining carfilzomib and obatoclax warrants attention in DLBCL. Mol Cancer Ther; 11(5); 1122–32. ©2012 AACR.
Data from REST Is a Novel Prognostic Factor and Therapeutic Target for Medulloblastoma
Authors: Taylor Pete , Fangusaro Jason , Rajaram Veena , Goldman Stewart , Helenowski Irene B. , MacDonald Tobey , Hasselblatt Martin , Riedemann Lars , Laureano Alvaro , Cooper Laurence , Gopalakrishnan Vidya
Published: April 2023

Abstract
Medulloblastoma is a malignant pediatric brain tumor. Current treatment following patient stratification into standard and high-risk groups using clinical features has improved survival. However, a subset of patients with standard risk features have unanticipated aggressive disease, underscoring the need for a better understanding of tumor biology and the development of novel treatments. Poor differentiation, a hallmark of medulloblastomas is associated with elevated expression levels of the repressor of neuronal differentiation called repressor element 1-silencing transcription factor (REST). Here, we assessed whether elevated REST expression levels had prognostic significance and whether its pharmacologic manipulation would promote neurogenesis and block tumor cell growth. REST levels in patient tumors were measured by immunohistochemistry and stratified into negative, low/moderate- (+/++/+++), and high-REST (+++++) groups. Kaplan–Meier curves revealed that patients with high-REST tumors had worse overall and event-free survival compared with patients with REST-negative or REST-low tumors. Because histone deacetylases (HDAC) are required for REST-dependent repression of neurogenesis, we evaluated a panel of HDAC inhibitors (HDACI) for their effects on growth and differentiation of established and primary REST-positive cell lines. MS-275, trichostatin-A (TSA), valproic acid (VPA), and suberoylanilide hydroxamic acid (SAHA) upregulated expression of the REST-target neuronal differentiation gene, Syn1, suggesting a potential effect of these HDACIs on REST function. Interestingly, VPA and TSA substantially increased histone acetylation at the REST promoter and activated its transcription, whereas SAHA unexpectedly promoted its proteasomal degradation. A REST-dependent decrease in cell growth was also observed following SAHA treatment. Thus, our studies suggest that HDACIs may have therapeutic potential for patients with REST-positive tumors. This warrants further investigation. Mol Cancer Ther; 11(8); 1713–23. ©2012 AACR.
Data from Growth Inhibition of Ovarian Tumor–Initiating Cells by Niclosamide
Authors: Yo Yi-Te , Lin Ya-Wen , Wang Yu-Chi , Balch Curt , Huang Rui-Lan , Chan Michael W.Y. , Sytwu Huey-Kang , Chen Chi-Kuan , Chang Cheng-Chang , Nephew Kenneth P. , Huang Tim , Yu Mu-Hsien , Lai Hung-Cheng
Published: April 2023

Abstract
A recent hypothesis for cancer chemoresistance posits that cytotoxic survival of a subpopulation of tumor progenitors drives the propagation of recurrent disease, underscoring the need for new therapeutics that target such primitive cells. To discover such novel compounds active against drug-resistant ovarian cancer, we identified a subset of chemoresistant ovarian tumor cells fulfilling current definitions of cancer-initiating cells from cell lines and patient tumors using multiple stemness phenotypes, including the expression of stem cell markers, membrane dye efflux, sphere formation, potent tumorigenicity, and serial tumor propagation. We then subjected such stem-like ovarian tumor-initiating cells (OTIC) to high-throughput drug screening using more than 1,200 clinically approved drugs. Of 61 potential compounds preliminarily identified, more stringent assessments showed that the antihelmintic niclosamide selectively targets OTICs in vitro and in vivo. Gene expression arrays following OTIC treatment revealed niclosamide to disrupt multiple metabolic pathways affecting biogenetics, biogenesis, and redox regulation. These studies support niclosamide as a promising therapy for ovarian cancer and warrant further preclinical and clinical evaluation of this safe, clinically proven drug for the management of this devastating gynecologic malignancy. Mol Cancer Ther; 11(8); 1703–12. ©2012 AACR.
Data from Genetic Variation That Predicts Platinum Sensitivity Reveals the Role of miR-193b* in Chemotherapeutic Susceptibility
Authors: Ziliak Dana , Gamazon Eric R. , LaCroix Bonnie , Kyung Im Hae , Wen Yujia , Huang Rong Stephanie
Published: April 2023

Abstract
Platinum agents are the backbone of cancer chemotherapy. Recently, we identified and replicated the role of a single nucleotide polymorphism (SNP, rs1649942) in predicting platinum sensitivity both in vitro and in vivo. Using the CEU samples from the International HapMap Project, we found the same SNP to be a master regulator of multiple gene expression phenotypes, prompting us to investigate whether rs1649942-mediated regulation of miRNAs may in part contribute to variation in platinum sensitivity. To these ends, 60 unrelated HapMap CEU I/II samples were used for our discovery-phase study using high-throughput genome-wide miRNA and gene expression profiling. Examining the relationships among rs1649942, its gene expression targets, genome-wide miRNA expression, and cellular sensitivity to carboplatin and cisplatin, we identified 2 platinum-associated miRNAs (miR-193b* and miR-320) that inhibit the expression of 5 platinum-associated genes (CRIM1, IFIT2, OAS1, KCNMA1, and GRAMD1B). We further replicated the relationship between the expression of miR-193b*, CRIM1, IFIT2, KCNMA1, and GRAMD1B, and platinum sensitivity in a separate HapMap CEU III dataset. We then showed that overexpression of miR-193b* in a randomly selected HapMap cell line results in resistance to both carboplatin and cisplatin. This relationship was also found in 7 ovarian cancer cell lines from NCI60 dataset and confirmed in an OVCAR-3 that overexpression of miR-193b* leads to increased resistance to carboplatin. Our findings highlight a potential mechanism of action for a previously observed genotype-survival outcome association. Further examination of miR-193b* in platinum sensitivity in ovarian cancer is warranted. Mol Cancer Ther; 11(9); 2054–61. ©2012 AACR.
Data from The Effect of Different Linkers on Target Cell Catabolism and Pharmacokinetics/Pharmacodynamics of Trastuzumab Maytansinoid Conjugates
Authors: Erickson Hans K. , Lewis Phillips Gail D. , Leipold Douglas D. , Provenzano Carmela A. , Mai Elaine , Johnson Holly A. , Gunter Bert , Audette Charlene A. , Gupta Manish , Pinkas Jan , Tibbitts Jay
Published: April 2023

Abstract
Trastuzumab emtansine (T-DM1) is an antibody–drug conjugate consisting of the anti-HER2 antibody trastuzumab linked via a nonreducible thioether linker to the maytansinoid antitubulin agent DM1. T-DM1 has shown favorable safety and efficacy in patients with HER2-positive metastatic breast cancer. In previous animal studies, T-DM1 exhibited better pharmacokinetics (PK) and slightly more efficacy than several disulfide-linked versions. The efficacy findings are unique, as other disulfide-linked antibody–drug conjugates (ADC) have shown greater efficacy than thioether-linked designs. To explore this further, the in vitro and in vivo activity, PK, and target cell activation of T-DM1 and the disulfide-linked T-SPP-DM1 were examined. Both ADCs showed high in vitro potency, with T-DM1 displaying greater potency in two of four breast cancer cell lines. In vitro target cell processing of T-DM1 and T-SPP-DM1 produced lysine-Nϵ-MCC-DM1, and lysine-Nϵ-SPP-DM1 and DM1, respectively; in vivo studies confirmed these results. The in vitro processing rates for the two conjugate to their respective catabolites were similar. In vivo, the potencies of the conjugates were similar, and T-SPP-DM1 had a faster plasma clearance than T-DM1. Slower T-DM1 clearance translated to higher overall tumor concentrations (conjugate plus catabolites), but unexpectedly, similar levels of tumor catabolite. These results indicate that, although the ADC linker can have clear impact on the PK and the chemical nature of the catabolites formed, both linkers seem to offer the same payload delivery to the tumor. Mol Cancer Ther; 11(5); 1133–42. ©2012 AACR.
Data from High TUBB3 Expression, an Independent Prognostic Marker in Patients with Early Non–Small Cell Lung Cancer Treated by Preoperative Chemotherapy, Is Regulated by K-Ras Signaling Pathway
Authors: Levallet Guénaëlle , Bergot Emmanuel , Antoine Martine , Creveuil Christian , Santos Adriana O. , Beau-Faller Michelle , de Fraipont Florence , Brambilla Elisabeth , Levallet Jérôme , Morin Franck , Westeel Virginie , Wislez Marie , Quoix Elisabeth , Debieuvre Didier , Dubois Fatéméh , Rouquette Isabelle , Pujol Jean-Louis , Moro-Sibilot Denis , Camonis Jacques , Zalcman Gérard
Published: April 2023

Abstract
We assessed the prognostic and predictive value of β-tubulin III (TUBB3) expression, as determined by immunohistochemistry, in 412 non–small cell lung cancer (NSCLC) specimens from early-stage patients who received neoadjuvant chemotherapy (paclitaxel- or gemcitabine-based) in a phase III trial (IFCT-0002). We also correlated TUBB3 expression with K-Ras and EGF receptor (EGFR) mutations in a subset of 208 cryopreserved specimens. High TUBB3 protein expression was associated with nonsquamous cell carcinomas (P < 0.001) and K-Ras mutation (P < 0.001). The 127 (30.8%) TUBB3-negative patients derived more than 1 year of overall survival advantage, with more than 84 months median overall survival versus 71.7 months for TUBB3-positive patients [HR, 1.58; 95% confidence interval (CI), 1.11–2.25)]. This prognostic value was confirmed in multivariate analysis (adjusted HR for death, 1.51; 95% CI, 1.04–2.21; P = 0.031) with a bootstrapping validation procedure. TUBB3 expression was associated with nonresponse to chemotherapy (adjusted HR, 1.31; 95% CI, 1.01–1.70; P = 0.044) but had no predictive value (taxane vs. gemcitabine). Taking account of these clinical findings, we further investigated TUBB3 expression in isogenic human bronchial cell lines only differing by K-Ras gene status and assessed the effect of K-Ras short interfering RNA (siRNA) mediated depletion, cell hypoxia, or pharmacologic inhibitors of K-Ras downstream effectors, on TUBB3 protein cell content. siRNA K-Ras knockdown, inhibition of RAF/MEK (MAP–ERK kinase) and phosphoinositide 3-kinase (PI3K)/AKT signaling, and hypoxia were shown to downregulate TUBB3 expression in bronchial cells. This study is the first one to identify K-Ras mutations as determinant of TUBB3 expression, a chemoresistance marker. Our in vitro data deserve studies combining standard chemotherapy with anti-MEK or anti-PI3K drugs in patients with TUBB3-overexpressing tumors. Mol Cancer Ther; 11(5); 1203–13. ©2012 AACR.
Data from APG350 Induces Superior Clustering of TRAIL Receptors and Shows Therapeutic Antitumor Efficacy Independent of Cross-Linking via Fcγ Receptors
Authors: Gieffers Christian , Kluge Michael , Merz Christian , Sykora Jaromir , Thiemann Meinolf , Schaal René , Fischer Carmen , Branschädel Marcus , Abhari Behnaz Ahangarian , Hohenberger Peter , Fulda Simone , Fricke Harald , Hill Oliver
Published: April 2023

Abstract
Cancer cells can be specifically driven into apoptosis by activating Death-receptor-4 (DR4; TRAIL-R1) and/or Death-receptor-5 (DR5; TRAIL-R2). Albeit showing promising preclinical efficacy, first-generation protein therapeutics addressing this pathway, especially agonistic anti-DR4/DR5-monoclonal antibodies, have not been clinically successful to date. Due to their bivalent binding mode, effective apoptosis induction by agonistic TRAIL-R antibodies is achieved only upon additional events leading to antibody-multimer formation. The binding of these multimers to their target subsequently leads to effective receptor-clustering on cancer cells. The research results presented here report on a new class of TRAIL-receptor agonists overcoming this intrinsic limitation observed for antibodies in general. The main feature of these agonists is a TRAIL-mimic consisting of three TRAIL-protomer subsequences combined in one polypeptide chain, termed the single-chain TRAIL-receptor–binding domain (scTRAIL-RBD). In the active compounds, two scTRAIL-RBDs with three receptor binding sites each are brought molecularly in close proximity resulting in a fusion protein with a hexavalent binding mode. In the case of APG350—the prototype of this engineering concept—this is achieved by fusing the Fc-part of a human immunoglobulin G1 (IgG1)-mutein C-terminally to the scTRAIL–RBD polypeptide, thereby creating six receptor binding sites per drug molecule. In vitro, APG350 is a potent inducer of apoptosis on human tumor cell lines and primary tumor cells. In vivo, treatment of mice bearing Colo205-xenograft tumors with APG350 showed a dose-dependent antitumor efficacy. By dedicated muteins, we confirmed that the observed in vivo efficacy of the hexavalent scTRAIL–RBD fusion proteins is—in contrast to agonistic antibodies—independent of FcγR-based cross-linking events. Mol Cancer Ther; 12(12); 2735–47. ©2013 AACR.
Data from Activity of a Py–Im Polyamide Targeted to the Estrogen Response Element
Authors: Nickols Nicholas G. , Szablowski Jerzy O. , Hargrove Amanda E. , Li Benjamin C. , Raskatov Jevgenij A. , Dervan Peter B.
Published: April 2023

Abstract
Pyrrole-imidazole (Py–Im) polyamides are a class of programmable DNA minor groove binders capable of modulating the activity of DNA-binding proteins and affecting changes in gene expression. Estrogen receptor alpha (ERα) is a ligand-activated hormone receptor that binds as a homodimer to estrogen response elements (ERE) and is a driving oncogene in a majority of breast cancers. We tested a selection of structurally similar Py–Im polyamides with differing DNA sequence specificity for activity against 17β-estadiol (E2)–induced transcription and cytotoxicity in ERα positive, E2-stimulated T47DKBluc cells, which express luciferase under ERα control. The most active polyamide targeted the sequence 5′-WGGWCW-3′ (W = A or T), which is the canonical ERE half site. Whole transcriptome analysis using RNA-Seq revealed that treatment of E2-stimulated breast cancer cells with this polyamide reduced the effects of E2 on the majority of those most strongly affected by E2 but had much less effect on the majority of E2-induced transcripts. In vivo, this polyamide circulated at detectable levels following subcutaneous injection and reduced levels of ER-driven luciferase expression in xenografted tumors in mice after subcutaneous compound administration without significant host toxicity. Mol Cancer Ther; 12(5); 675–84. ©2013 AACR.
Data from Identification of Docetaxel Resistance Genes in Castration-Resistant Prostate Cancer
Authors: Marín-Aguilera Mercedes , Codony-Servat Jordi , Kalko Susana G. , Fernández Pedro L. , Bermudo Raquel , Buxo Elvira , Ribal María José , Gascón Pedro , Mellado Begoña
Published: April 2023

Abstract
Docetaxel-based chemotherapy is the standard first-line therapy in metastatic castration-resistant prostate cancer (CRPC). However, most patients eventually develop resistance to this treatment. In this study, we aimed to identify key molecular genes and networks associated with docetaxel resistance in two models of docetaxel-resistant CRPC cell lines and to test for the most differentially expressed genes in tumor samples from patients with CRPC. DU-145 and PC-3 cells were converted to docetaxel-resistant cells, DU-145R and PC-3R, respectively. Whole-genome arrays were used to compare global gene expression between these four cell lines. Results showed differential expression of 243 genes (P < 0.05, Bonferroni-adjusted P values and log ratio > 1.2) that were common to DU-145R and PC-3R cells. These genes were involved in cell processes like growth, development, death, proliferation, movement, and gene expression. Genes and networks commonly deregulated in both DU-145R and PC-3R cells were studied by Ingenuity Pathways Analysis. Exposing parental cells to TGFB1 increased their survival in the presence of docetaxel, suggesting a role of the TGF-β superfamily in conferring drug resistance. Changes in expression of 18 selected genes were validated by real-time quantitative reverse transcriptase PCR in all four cell lines and tested in a set of 11 FFPE and five optimal cutting temperature tumor samples. Analysis in patients showed a noteworthy downexpression of CDH1 and IFIH1, among others, in docetaxel-resistant tumors. This exploratory analysis provides information about potential gene and network involvement in docetaxel resistance in CRPC. Further clinical validation of these results is needed to develop targeted therapies in patients with CRPC that can circumvent such resistance to treatment. Mol Cancer Ther; 11(2); 329–39. ©2011 AACR.
Data from Histone Deacetylase Inhibition Overcomes Drug Resistance through a miRNA-Dependent Mechanism
Authors: Murray-Stewart Tracy , Hanigan Christin L. , Woster Patrick M. , Marton Laurence J. , Casero Robert A.
Published: April 2023

Abstract
The treatment of specific tumor cell lines with poly- and oligoamine analogs results in a superinduction of polyamine catabolism that is associated with cytotoxicity; however, other tumor cells show resistance to analog treatment. Recent data indicate that some of these analogs also have direct epigenetic effects. We, therefore, sought to determine the effects of combining specific analogs with an epigenetic targeting agent in phenotypically resistant human lung cancer cell lines. We show that the histone deacetylase inhibitor MS-275, when combined with (N1, N11)-bisethylnorspermine (BENSpm) or (N1, N12)-bis(ethyl)-cis-6,7-dehydrospermine tetrahydrochloride (PG-11047), synergistically induces the polyamine catabolic enzyme spermidine/spermine N1-acetyltransferase (SSAT), a major determinant of sensitivity to the antitumor analogs. Evidence indicates that the mechanism of this synergy includes reactivation of miR-200a, which targets and destabilizes kelch-like ECH-associated protein 1 (KEAP1) mRNA, resulting in the translocation and binding of nuclear factor (erythroid-derived 2)-like 2 (NRF2) to the polyamine-responsive element of the SSAT promoter. This transcriptional stimulation, combined with positive regulation of SSAT mRNA and protein by the analogs, results in decreased intracellular concentrations of natural polyamines and growth inhibition. The finding that an epigenetic targeting agent is capable of inducing a rate-limiting step in polyamine catabolism to overcome resistance to the antitumor analogs represents a completely novel chemotherapeutic approach. In addition, this is the first demonstration of miRNA-mediated regulation of the polyamine catabolic pathway. Furthermore, the individual agents used in this study have been investigated clinically; therefore, translation of these combinations into the clinical setting holds promise. Mol Cancer Ther; 12(10); 2088–99. ©2013 AACR.
Data from VS-5584, a Novel and Highly Selective PI3K/mTOR Kinase Inhibitor for the Treatment of Cancer
Authors: Hart Stefan , Novotny-Diermayr Veronica , Goh Kee Chuan , Williams Meredith , Tan Yong Cheng , Ong Lai Chun , Cheong Albert , Ng Bee Kheng , Amalini Chithra , Madan Babita , Nagaraj Harish , Jayaraman Ramesh , Pasha Khalid M. , Ethirajulu Kantharaj , Chng Wee Joo , Mustafa Nurulhuda , Goh Boon Cher , Benes Cyril , McDermott Ultan , Garnett Mathew , Dymock Brian , Wood Jeanette M.
Published: April 2023

Abstract
Dysregulation of the PI3K/mTOR pathway, either through amplifications, deletions, or as a direct result of mutations, has been closely linked to the development and progression of a wide range of cancers. Moreover, this pathway activation is a poor prognostic marker for many tumor types and confers resistance to various cancer therapies. Here, we describe VS-5584, a novel, low-molecular weight compound with equivalent potent activity against mTOR (IC50 = 37 nmol/L) and all class I phosphoinositide 3-kinase (PI3K) isoforms IC50: PI3Kα = 16 nmol/L; PI3Kβ = 68 nmol/L; PI3Kγ = 25 nmol/L; PI3Kδ = 42 nmol/L, without relevant activity on 400 lipid and protein kinases. VS-5584 shows robust modulation of cellular PI3K/mTOR pathways, inhibiting phosphorylation of substrates downstream of PI3K and mTORC1/2. A large human cancer cell line panel screen (436 lines) revealed broad antiproliferative sensitivity and that cells harboring mutations in PI3KCA are generally more sensitive toward VS-5584 treatment. VS-5584 exhibits favorable pharmacokinetic properties after oral dosing in mice and is well tolerated. VS-5584 induces long-lasting and dose-dependent inhibition of PI3K/mTOR signaling in tumor tissue, leading to tumor growth inhibition in various rapalog-sensitive and -resistant human xenograft models. Furthermore, VS-5584 is synergistic with an EGF receptor inhibitor in a gastric tumor model. The unique selectivity profile and favorable pharmacologic and pharmaceutical properties of VS-5584 and its efficacy in a wide range of human tumor models supports further investigations of VS-5584 in clinical trials. Mol Cancer Ther; 12(2); 151–61. ©2012 AACR.
Data from Gene Expression Profile in Response to Doxorubicin–Rapamycin Combined Treatment of HER-2–Overexpressing Human Mammary Epithelial Cell Lines
Authors: Trapé Adriana Priscila , Katayama Maria Lucia Hirata , Roela Rosimeire Aparecida , Brentani Helena , Ravacci Graziela Rosa , de Araujo Lima Leandro , Brentani Maria Mitzi
Published: April 2023

Abstract
HER-2–positive breast cancers frequently sustain elevated AKT/mTOR signaling, which has been associated with resistance to doxorubicin treatment. Here, we investigated whether rapamycin, an mTOR inhibitor, increased the sensitivity to doxorubicin therapy in two HER-2–overexpressing cell lines: C5.2, which was derived from the parental HB4a by transfection with HER-2 and SKBR3, which exhibits HER-2 amplification. The epithelial mammary cell line HB4a was also analyzed. The combined treatment using 20 nmol/L of rapamycin and 30 nmol/L of doxorubicin arrested HB4a and C5.2 cells in S to G2–M, whereas SKBR3 cells showed an increase in the G0–G1 phase. Rapamycin increased the sensitivity to doxorubicin in HER-2–overexpressing cells by approximately 2-fold, suggesting that the combination displayed a more effective antiproliferative action. Gene expression profiling showed that these results might reflect alterations in genes involved in canonical pathways related to purine metabolism, oxidative phosphorylation, protein ubiquitination, and mitochondrial dysfunction. A set of 122 genes modulated by the combined treatment and specifically related to HER-2 overexpression was determined by finding genes commonly regulated in both C5.2 and SKBR3 that were not affected in HB4a cells. Network analysis of this particular set showed a smaller subgroup of genes in which coexpression pattern in HB4a cells was disrupted in C5.2 and SKBR3. Altogether, our data showed a subset of genes that might be more robust than individual markers in predicting the response of HER-2–overexpressing breast cancers to doxorubicin and rapamycin combination. Mol Cancer Ther; 11(2); 464–74. ©2011 AACR.
Data from The Dual Pathway Inhibitor Rigosertib Is Effective in Direct Patient Tumor Xenografts of Head and Neck Squamous Cell Carcinomas
Authors: Anderson Ryan T. , Keysar Stephen B. , Bowles Daniel W. , Glogowska Magdalena J. , Astling David P. , Morton J. Jason , Le Phuong , Umpierrez Adrian , Eagles-Soukup Justin , Gan Gregory N. , Vogler Brian W. , Sehrt Daniel , Takimoto Sarah M. , Aisner Dara L. , Wilhelm Francois , Frederick Barbara A. , Varella-Garcia Marileila , Tan Aik-Choon , Jimeno Antonio
Published: April 2023

Abstract
The dual pathway inhibitor rigosertib inhibits phosphoinositide 3-kinase (PI3K) pathway activation as well as polo-like kinase 1 (PLK1) activity across a broad spectrum of cancer cell lines. The importance of PIK3CA alterations in squamous cell carcinoma of the head and neck (HNSCC) has raised interest in exploring agents targeting PI3K, the product of PIK3CA. The genetic and molecular basis of rigosertib treatment response was investigated in a panel of 16 HNSCC cell lines, and direct patient tumor xenografts from eight patients with HNSCC [four HPV-serotype16 (HPV16)–positive]. HNSCC cell lines and xenografts were characterized by pathway enrichment gene expression analysis, exon sequencing, gene copy number, Western blotting, and immunohistochemistry (IHC). Rigosertib had potent antiproliferative effects on 11 of 16 HPV− HNSCC cell lines. Treatment sensitivity was confirmed in two cell lines using an orthotopic in vivo xenograft model. Growth reduction after rigosertib treatment was observed in three of eight HNSCC direct patient tumor lines. The responsive tumor lines carried a combination of a PI3KCA-activating event (amplification or mutation) and a p53-inactivating event (either HPV16- or mutation-mediated TP53 inactivation). In this study, we evaluated the in vitro and in vivo efficacy of rigosertib in both HPV+ and HPV− HNSCCs, focusing on inhibition of the PI3K pathway. Although consistent inhibition of the PI3K pathway was not evident in HNSCC, we identified a combination of PI3K/TP53 events necessary, but not sufficient, for rigosertib sensitivity. Mol Cancer Ther; 12(10); 1994–2005. ©2013 AACR.
Data from BRAF V600E Is a Determinant of Sensitivity to Proteasome Inhibitors
Authors: Zecchin Davide , Boscaro Valentina , Medico Enzo , Barault Ludovic , Martini Miriam , Arena Sabrina , Cancelliere Carlotta , Bartolini Alice , Crowley Emily H. , Bardelli Alberto , Gallicchio Margherita , Di Nicolantonio Federica
Published: April 2023

Abstract
A critical step toward defining tailored therapy in patients with cancer is the identification of genetic interactions that may impair—or boost—the efficacy of selected therapeutic approaches. Cell models able to recapitulate combinations of genetic aberrations are important to find drug–genotype interactions poorly affected by the heterogeneous genetics of human tumors. In order to identify novel pharmacogenomic relationships, we employed an isogenic cell panel that reconstructs cancer genetic scenarios. We screened a library of 43 compounds in human hTERT-HME1 epithelial cells in which PTEN or RB1 were silenced in combination with the targeted knockin of cancer-associated mutations in EGFR, KRAS, BRAF, or PIK3CA oncogenes. Statistical analysis and clustering algorithms were applied to display similar drug response profiles and mutation-specific patterns of activity. From the screen, we discovered that proteasome inhibitors show selectivity toward BRAF V600E–mutant cells, irrespective of PTEN or RB1 expression. Preferential targeting of BRAF-mutant cells by proteasome inhibitors was corroborated in a second BRAF V600E isogenic model, as well as in a panel of colorectal cancer cell lines by the use of the proteasome inhibitor carfilzomib. Notably, carfilzomib also showed striking in vivo activity in a BRAF-mutant human colorectal cancer xenograft model. Vulnerability to proteasome inhibitors is dependent on persistent BRAF signaling, because BRAF V600E blockade by PLX4720 reversed sensitivity to carfilzomib in BRAF-mutant colorectal cancer cells. Our findings indicated that proteasome inhibition might represent a valuable targeting strategy in BRAF V600E–mutant colorectal tumors. Mol Cancer Ther; 12(12); 2950–61. ©2013 AACR.
Data from Low Levels of Circulating Estrogen Sensitize PTEN-Null Endometrial Tumors to PARP Inhibition In Vivo
Authors: Janzen Deanna M. , Paik Daniel Y. , Rosales Miguel A. , Yep Brian , Cheng Donghui , Witte Owen N. , Kayadibi Huseyin , Ryan Christopher M. , Jung Michael E. , Faull Kym , Memarzadeh Sanaz
Published: April 2023

Abstract
Earlier in vitro work demonstrated that PARP inhibition induces cell death in PTEN-null endometrial cancer cell lines, but the in vivo therapeutic efficacy of these agents against endometrial cancer remains unknown. Here, we test the efficacy of AZD2281 (olaparib), an oral PARP inhibitor, in the therapy of PTEN-null endometrial tumors in a preclinical endometrial cancer mouse model. Primary endometrial tumors were generated by epithelial loss of PTEN using an in vivo model. This model recapitulates epithelial-specific loss of PTEN seen in human tumors, and histologically resembles endometrioid carcinomas, the predominant subtype of human endometrial cancers. Olaparib was administered orally to tumor-bearing mice in two hormonal extremes: high or low estrogen. Olaparib treatment achieved a significant reduction in tumor size in a low estrogenic milieu. In striking contrast, no response to olaparib was seen in tumors exposed to high levels of estrogen. Two key observations were made when estrogen levels were dropped: (i) the serum concentration of olaparib was significantly increased, resulting in sustained PARP inhibition at the tumor bed; and (ii) the homologous recombination pathway was compromised, as evidenced by decreased Rad51 protein expression and function. These two mechanisms may account for the sensitization of PTEN-null tumors to olaparib with estrogen deprivation. Results of this preclinical trial suggest that orally administered PARP inhibitors in a low estrogenic hormonal milieu can effectively target PTEN-null endometrial tumors. Extension of this work to clinical trials could personalize the therapy of women afflicted with advanced endometrial cancer using well-tolerated orally administered therapeutic agents. Mol Cancer Ther; 12(12); 2917–28. ©2013 AACR.
Data from The Novel VEGF Receptor/MET–Targeted Kinase Inhibitor TAS-115 Has Marked In Vivo Antitumor Properties and a Favorable Tolerability Profile
Authors: Fujita Hidenori , Miyadera Kazutaka , Kato Masanori , Fujioka Yayoi , Ochiiwa Hiroaki , Huang Jinhong , Ito Kimihiro , Aoyagi Yoshimi , Takenaka Toru , Suzuki Takamasa , Ito Satoko , Hashimoto Akihiro , Suefuji Takashi , Egami Kosuke , Kazuno Hideki , Suda Yoshimitsu , Nishio Kazuto , Yonekura Kazuhiko
Published: April 2023

Abstract
VEGF receptor (VEGFR) signaling plays a key role in tumor angiogenesis. Although some VEGFR signal-targeted drugs have been approved for clinical use, their utility is limited by associated toxicities or resistance to such therapy. To overcome these limitations, we developed TAS-115, a novel VEGFR and hepatocyte growth factor receptor (MET)-targeted kinase inhibitor with an improved safety profile. TAS-115 inhibited the kinase activity of both VEGFR2 and MET and their signal-dependent cell growth as strongly as other known VEGFR or MET inhibitors. On the other hand, kinase selectivity of TAS-115 was more specific than that of sunitinib and TAS-115 produced relatively weak inhibition of growth (GI50 > 10 μmol/L) in VEGFR signal- or MET signal-independent cells. Furthermore, TAS-115 induced less damage in various normal cells than did other VEGFR inhibitors. These data suggest that TAS-115 is extremely selective and specific, at least in vitro. In in vivo studies, TAS-115 completely suppressed the progression of MET-inactivated tumor by blocking angiogenesis without toxicity when given every day for 6 weeks, even at a serum-saturating dose of TAS-115. The marked selectivity of TAS-115 for kinases and targeted cells was associated with improved tolerability and contributed to the ability to sustain treatment without dose reduction or a washout period. Furthermore, TAS-115 induced marked tumor shrinkage and prolonged survival in MET-amplified human cancer–bearing mice. These data suggest that TAS-115 is a unique VEGFR/MET-targeted inhibitor with improved antitumor efficacy and decreased toxicity. Mol Cancer Ther; 12(12); 2685–96. ©2013 AACR.
Data from Antitumor Activity of Src Inhibitor Saracatinib (AZD-0530) in Preclinical Models of Biliary Tract Carcinomas
Authors: Cavalloni Giuliana , Peraldo-Neia Caterina , Sarotto Ivana , Gammaitoni Loretta , Migliardi Giorgia , Soster Marco , Marchiò Serena , Aglietta Massimo , Leone Francesco
Published: April 2023

Abstract
Biliary tract carcinoma (BTC) has a poor prognosis due to limited treatment options. There is, therefore, an urgent need to identify new targets and to design innovative therapeutic approaches. Among potential candidate molecules, we evaluated the nonreceptor tyrosine kinase Src, observing promising antitumor effects of its small-molecule inhibitor saracatinib in BTC preclinical models. The presence of an active Src protein was investigated by immunohistochemistry in 19 surgical samples from patients with BTC. Upon saracatinib treatment, the phosphorylation of Src and of its downstream transducers was evaluated in the BTC cell lines TFK-1, EGI-1, HuH28, and TGBC1-TKB. The effect of saracatinib on proliferation and migration was analyzed in these same cell lines, and its antitumor activity was essayed in EGI-1 mouse xenografts. Saracatinib-modulated transcriptome was profiled in EGI-1 cells and in tumor samples of the xenograft model. Src was activated in about 80% of the human BTC samples. In cultured BTC cell lines, low-dose saracatinib counteracted the activation of Src and of its downstream effectors, increased the fraction of cells in G0–G1 phase, and inhibited cell migration. At high concentrations (median dose from 2.26–6.99 μmol/L), saracatinib was also capable of inhibiting BTC cell proliferation. In vivo, saracatinib treatment resulted in delayed tumor growth, associated with an impaired vascular network. Here, we provide a demonstration that the targeted inhibition of Src kinase by saracatinib is of therapeutic benefit in preclinical models of BTC. We propose our results as a basis for the design of saracatinib-based clinical applications. Mol Cancer Ther; 11(7); 1528–38. ©2012 AACR.
Data from Cotargeting MAPK and PI3K Signaling with Concurrent Radiotherapy as a Strategy for the Treatment of Pancreatic Cancer
Authors: Williams Terence M. , Flecha Athena R. , Keller Paul , Ram Ashwin , Karnak David , Galbán Stefanie , Galbán Craig J. , Ross Brian D. , Lawrence Theodore S. , Rehemtulla Alnawaz , Sebolt-Leopold Judith
Published: April 2023

Abstract
There is an urgent need for the development of novel therapies to treat pancreatic cancer, which is among the most lethal of all cancers. KRAS-activating mutations, which are found in more than 90% of pancreatic adenocarcinomas, drive tumor dependency on the Ras/MAPK and Akt signaling pathways. Radiation is currently being explored as a component of the standard treatment regimen for pancreatic cancer. This study's purpose was to test the hypothesis that MAP kinase kinase (MEK or MAP2K) inhibitors will offer clear therapeutic benefit when integrated into radiotherapy treatment regimens for treatment of this disease. We explored the activation of the mitogen-activated protein kinase (MAPK) and Akt pathways in response to radiation in multiple pancreatic tumor cell lines. Small molecule inhibitors of MEK (PD0325901) and Akt (API-2) were subsequently evaluated for their radiosensitizing potential alone and in combination. In vivo efficacy was tested in subcutaneous MIA-PaCa2 xenografts. Phosphorylated levels of extracellular signal–regulated kinase (ERK)-1/2 and Akt were found to increase in response to radiation treatment in our pancreatic tumor cell line panel. MEK inhibitor–induced radiosensitization was observed in vitro and in vivo. The further addition of an Akt inhibitor to the MEK inhibitor/radiation regimen resulted in enhanced therapeutic gain as determined by increased radiosensitization and tumor cell death. In conclusion, MEK inhibition results in growth arrest, apoptosis, and radiosensitization of multiple preclinical pancreatic tumor models, and the effects can be enhanced by combination with an Akt inhibitor. These results provide rationale for further testing of a treatment regimen in pancreatic cancer that combines MEK inhibition with radiation, optimally in conjunction with Akt inhibition. Mol Cancer Ther; 11(5); 1193–202. ©2012 AACR.
Data from Quantitative Chemical Proteomics Profiling Differentiates Erlotinib from Gefitinib in EGFR Wild-Type Non–Small Cell Lung Carcinoma Cell Lines
Authors: Augustin Angélique , Lamerz Jens , Meistermann Hélène , Golling Sabrina , Scheiblich Stefan , Hermann Johannes C. , Duchateau-Nguyen Guillemette , Tzouros Manuel , Avila David W. , Langen Hanno , Essioux Laurent , Klughammer Barbara
Published: April 2023

Abstract
Although both erlotinib and gefitinib target the EGF receptor (EGFR), erlotinib is effective in patients with EGFR wild-type or mutated tumors, whereas gefitinib is only beneficial for patients with activating mutations. To determine whether these differences in clinical outcomes can be attributed to their respective protein interaction profiles, a label-free, quantitative chemical proteomics study was conducted. Using this method, 24 proteins were highlighted in the binding profiles of erlotinib and gefitinib. Unlike gefinitib, erlotinib displaced the ternary complex formed by integrin-linked kinase (ILK), α-parvin, and PINCH (IPP). The docking of erlotinib in the three-dimensional structure of ILK showed that erlotinib has the ability to bind to the ATP-binding site, whereas gefitinib is unlikely to bind with high affinity. As the IPP complex has been shown to be involved in epithelial-to-mesenchymal transition (EMT) and erlotinib sensitivity has been correlated with EMT status, we used a cellular model of inducible transition and observed that erlotinib prevented EMT in a more efficient way than gefitinib by acting on E-cadherin expression as well as on IPP levels. A retrospective analysis of the MERIT trial indicated that, besides a high level of E-cadherin, a low level of ILK could be linked to clinical benefit with erlotinib. In conclusion, we propose that, in an EGFR wild-type context, erlotinib may have a complementary mode of action by inhibiting IPP complex activities, resulting in the slowing down of the metastatic process of epithelial tumors. Mol Cancer Ther; 12(4); 520–9. ©2013 AACR.
Data from The Inhibitor of Histone Deacetylases Sodium Butyrate Enhances the Cytotoxicity of Mitomycin C
Authors: Gospodinov Anastas , Popova Stanislava , Vassileva Ivelina , Anachkova Boyka
Published: April 2023

Abstract
The use of histone deacetylase inhibitors has been proposed as a promising approach to increase the cell killing effect of DNA damage–inducing drugs in chemotherapy. However, the molecular mechanism of their action remains understudied. In the present article, we have assessed the effect of the histone deacetylase inhibitor sodium butyrate on the DNA damage response induced by the crosslinking agent mitomycin C. Sodium butyrate increased mitomycin C cytotoxicity, but did not impair the repair pathways required to remove mitomycin C-induced lesions as neither the rate of nucleotide excision repair nor the homologous recombination repair rate were diminished. Sodium butyrate treatment abrogated the S-phase cell-cycle checkpoint in mitomycin C-treated cells and induced the G2–M checkpoint. However, sodium butyrate treatment alone resulted in accumulation of reactive oxygen species, double-strand breaks in DNA, and apoptosis. These results imply that the accumulation of reactive oxygen species–mediated increase in DNA lesion burden may be the major mechanism by which sodium butyrate enhances the cytotoxicity of mitomycin C. Mol Cancer Ther; 11(10); 2116–26. ©2012 AACR.