bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Antitumor Action of the MET Tyrosine Kinase Inhibitor Crizotinib (PF-02341066) in Gastric Cancer Positive for MET Amplification
Authors: Okamoto Wataru , Okamoto Isamu , Arao Tokuzo , Kuwata Kiyoko , Hatashita Erina , Yamaguchi Haruka , Sakai Kazuko , Yanagihara Kazuyoshi , Nishio Kazuto , Nakagawa Kazuhiko
Published: April 2023

Abstract
Therapeutic strategies that target the tyrosine kinase MET hold promise for gastric cancer, but the mechanism underlying the antitumor activity of such strategies remains unclear. We examined the antitumor action of the MET tyrosine kinase inhibitor crizotinib (PF-02341066) in gastric cancer cells positive or negative for MET amplification. Inhibition of MET signaling by crizotinib or RNA interference–mediated MET depletion resulted in induction of apoptosis accompanied by inhibition of AKT and extracellular signal–regulated kinase phosphorylation in gastric cancer cells with MET amplification but not in those without it, suggesting that MET signaling is essential for the survival of MET amplification–positive cells. Crizotinib upregulated the expression of BIM, a proapoptotic member of the Bcl-2 family, as well as downregulated that of survivin, X-linked inhibitor of apoptosis protein (XIAP), and c-IAP1, members of the inhibitor of apoptosis protein family, in cells with MET amplification. Forced depletion of BIM inhibited crizotinib-induced apoptosis, suggesting that upregulation of BIM contributes to the proapoptotic effect of crizotinib. Crizotinib also exhibited a marked antitumor effect in gastric cancer xenografts positive for MET amplification, whereas it had little effect on those negative for this genetic change. Crizotinib thus shows a marked antitumor action both in vitro and in vivo specifically in gastric cancer cells positive for MET amplification. Mol Cancer Ther; 11(7); 1557–64. ©2012 AACR.
Data from Modulation of p53 C-Terminal Acetylation by mdm2, p14ARF, and Cytoplasmic SirT2
Authors: van Leeuwen Ingeborg M.M. , Higgins Maureen , Campbell Johanna , McCarthy Anna R. , Sachweh Marijke C.C. , Navarro Ana Marín , Laín Sonia
Published: April 2023

Abstract
Acetylation of C-terminal lysine residues in the p53 tumor suppressor is associated with increased stability and transcription factor activity. The function, protein level, and acetylation of p53 are downregulated by mdm2, which in its turn is inhibited by the p14ARF tumor suppressor. Here, we show that p14ARF increases the level of p53 acetylated at lysine 382 in a nuclear chromatin-rich fraction. Unexpectedly, this accumulation of p53AcK382 is dramatically enhanced in the presence of ectopic mdm2. In light of these observations, we propose that p14ARF increases the binding of p53–mdm2 complexes to chromatin, thereby limiting the access of protein deacetylases to p53. Supporting this notion, we show that p53AcK382 can be deacetylated in the cytoplasm and that sirtuin SirT2 catalyzes this reaction. These results help understand why inhibition of both SirT1 and SirT2 is needed to achieve effective activation of p53 by small-molecule sirtuin inhibitors. Mol Cancer Ther; 12(4); 471–80. ©2013 AACR.
Data from HER2-Targeted Hybrid Peptide That Blocks HER2 Tyrosine Kinase Disintegrates Cancer Cell Membrane and Inhibits Tumor Growth In Vivo
Authors: Kawamoto Megumi , Horibe Tomohisa , Kohno Masayuki , Kawakami Koji
Published: April 2023

Abstract
HER2 is a transmembrane oncoprotein encoded by the HER2/neu gene and is overexpressed in approximately 20% to 30% of breast cancers. We have recently designed a novel class of drug, the hybrid peptide, which is chemically synthesized and is composed of a target-binding peptide and a lytic peptide containing cationic-rich amino acid components that disintegrate the cell membrane, leading to cancer cell death via membrane lysis. In this study, we designed a HER2-binding peptide linked to this novel lytic peptide, which we termed the HER2-lytic hybrid peptide and assessed the cytotoxic activity of this hybrid peptide in vitro and in vivo. The HER2-lytic hybrid peptide showed high cytotoxic activity against all ovarian and breast cancer cell lines, even trastuzumab- and/or lapatinib-resistant cells, but not against normal cells. Competition assays using anti-HER2 antibody and knockdown of this receptor by siRNA confirmed the specificity of the HER2-lytic hybrid peptide. In addition, it was shown that the HER2-lytic hybrid peptide can disintegrate the cancer cell membrane of HER2-overexpressing SK-BR-3 cancer cells in only 5 minutes, but not normal cells, and block HER2 signaling. Intravenous administration of the HER2-lytic peptide in the athymic mouse implanted with BT-474 and MDA-MB-453 cells significantly inhibited tumor progression. The HER2-lytic hybrid peptide was effective even in breast cancer cell lines that are resistant to trastuzumab and/or lapatinib in vitro and in vivo. Therefore, this hybrid peptide may provide a potent treatment option for patients with cancer. Mol Cancer Ther; 12(4); 384–93. ©2013 AACR.
Data from ATP Citrate Lyase Knockdown Induces Growth Arrest and Apoptosis through Different Cell- and Environment-Dependent Mechanisms
Authors: Zaidi Nousheen , Royaux Ines , Swinnen Johannes V. , Smans Karine
Published: April 2023

Abstract
ATP citrate lyase (ACLY) is a cytosolic enzyme that catalyzes generation of acetyl-CoA, which is a vital building block for fatty acid, cholesterol, and isoprenoid biosynthesis. ACLY is upregulated in several types of cancer, and its inhibition induces proliferation arrest in certain cancer cells. As ACLY is involved in several pathways, its downregulation may affect multiple processes. Here, we have shown that short hairpin RNA-mediated ACLY silencing in cell lines derived from different types of cancers induces proliferation, cell-cycle arrest, and apoptosis. However, this antiproliferative effect of ACLY knockdown was observed only when cells were cultivated under lipid-reduced growth conditions. Proliferation arrest induced by ACLY silencing was partially rescued by supplementing the media with fatty acids and/or cholesterol. This indicates that the ACLY knockdown-mediated growth arrest might be the result of either fatty acid or cholesterol starvation or both. In the absence of ACLY, the cancer cells displayed elevated expression of sterol regulatory element binding protein–regulated downstream genes involved in de novo fatty acid and cholesterol biosynthesis. Furthermore, ACLY suppression resulted in elevated expression of acyl-CoA synthetase short-chain family member 2 (ACSS2), an enzyme that also produces acetyl-CoA using acetate as a substrate. Acetate supplementation partially rescued the cancer cells from ACLY suppression–induced proliferation arrest. We also observed that the absence of ACLY enhanced ACSS2-dependent lipid synthesis. These findings provide new insights into the role of ACLY in cancer cell growth and give critical information about the effects of ACLY silencing on different pathways. This information is crucial in understanding the possible application of ACLY inhibition in cancer therapeutics. Mol Cancer Ther; 11(9); 1925–35. ©2012 AACR.
Data from YM155 Reverses Cisplatin Resistance in Head and Neck Cancer by Decreasing Cytoplasmic Survivin Levels
Authors: Kumar Bhavna , Yadav Arti , Lang James C. , Cipolla Michael J. , Schmitt Alessandra C. , Arradaza Nicole , Teknos Theodoros N. , Kumar Pawan
Published: April 2023

Abstract
Cisplatin is one of the commonly used chemotherapeutic drugs for the treatment of head and neck squamous cell carcinoma (HNSCC). However, acquisition of cisplatin resistance is common in patients with HNSCC, and it often leads to local and distant failure. In this study, we showed that survivin expression is significantly upregulated in HNSCC primary tumors and cell lines. In addition, survivin levels were significantly higher in human papilloma virus–negative patients that normally respond poorly to cisplatin treatment. Survivin expression was further increased in cisplatin-resistant cells (CAL27-CisR) as compared with its parent cells (CAL27). Therefore, we hypothesized that targeting of survivin in HNSCC could reverse the resistant phenotype in tumor cells, thereby enhancing the therapeutic efficacy of cisplatin. We used both in vitro and in vivo models to test the efficacy of YM155, a small molecule survivin inhibitor, either as a single agent or in combination with cisplatin. YM155 significantly decreased survivin levels and cell proliferation in a dose-dependent manner. In addition, YM155 pretreatment significantly reversed cisplatin resistance in cancer cells. Interestingly, YM155 treatment altered the dynamic localization of survivin in cells by inducing a rapid reduction in cytoplasmic survivin, which plays a critical role in its antiapoptotic function. In a severe combined immunodeficient mouse xenograft model, YM155 significantly enhanced the antitumor and antiangiogenic effects of cisplatin, with no added systemic toxicity. Taken together, our results suggest a potentially novel strategy to use YM155 to overcome the resistance in tumor cells, thereby enhancing the effectiveness of the chemotherapy in HNSCC. Mol Cancer Ther; 11(9); 1988–98. ©2012 AACR.
Data from A Role for Homologous Recombination and Abnormal Cell-Cycle Progression in Radioresistance of Glioma-Initiating Cells
Authors: Lim Yi Chieh , Roberts Tara L. , Day Bryan W. , Harding Angus , Kozlov Sergei , Kijas Amanda W. , Ensbey Kathleen S. , Walker David G. , Lavin Martin F.
Published: April 2023

Abstract
Glioblastoma multiforme (GBM) is the most common form of brain tumor with a poor prognosis and resistance to radiotherapy. Recent evidence suggests that glioma-initiating cells play a central role in radioresistance through DNA damage checkpoint activation and enhanced DNA repair. To investigate this in more detail, we compared the DNA damage response in nontumor forming neural progenitor cells (NPC) and glioma-initiating cells isolated from GBM patient specimens. As observed for GBM tumors, initial characterization showed that glioma-initiating cells have long-term self-renewal capacity. They express markers identical to NPCs and have the ability to form tumors in an animal model. In addition, these cells are radioresistant to varying degrees, which could not be explained by enhanced nonhomologous end joining (NHEJ). Indeed, NHEJ in glioma-initiating cells was equivalent, or in some cases reduced, as compared with NPCs. However, there was evidence for more efficient homologous recombination repair in glioma-initiating cells. We did not observe a prolonged cell cycle nor enhanced basal activation of checkpoint proteins as reported previously. Rather, cell-cycle defects in the G1–S and S-phase checkpoints were observed by determining entry into S-phase and radioresistant DNA synthesis following irradiation. These data suggest that homologous recombination and cell-cycle checkpoint abnormalities may contribute to the radioresistance of glioma-initiating cells and that both processes may be suitable targets for therapy. Mol Cancer Ther; 11(9); 1863–72. ©2012 AACR.
Data from Synthetic Lethal Screening with Small-Molecule Inhibitors Provides a Pathway to Rational Combination Therapies for Melanoma
Authors: Roller Devin G. , Axelrod Mark , Capaldo Brian J. , Jensen Karin , Mackey Aaron , Weber Michael J. , Gioeli Daniel
Published: April 2023

Abstract
Recent data show that extracellular signals are transmitted through a network of proteins rather than hierarchical signaling pathways, suggesting that the inhibition of a single component of a canonical pathway is insufficient for the treatment of cancer. The biologic outcome of signaling through a network is inherently more robust and resistant to inhibition of a single network component. In this study, we conducted a functional chemical genetic screen to identify novel interactions between signaling inhibitors that would not be predicted on the basis of our current understanding of signaling networks. We screened over 300 drug combinations in nine melanoma cell lines and have identified pairs of compounds that show synergistic cytotoxicity. The synergistic cytotoxicities identified did not correlate with the known RAS and BRAF mutational status of the melanoma cell lines. Among the most robust results was synergy between sorafenib, a multikinase inhibitor with activity against RAF, and diclofenac, a nonsteroidal anti-inflammatory drug (NSAID). Drug substitution experiments using the NSAIDs celecoxib and ibuprofen or the MAP–ERK kinase inhibitor PD325901 and the RAF inhibitor RAF265 suggest that inhibition of COX and mitogen-activated protein kinase signaling are targets for the synergistic cytotoxicity of sorafenib and diclofenac. Cotreatment with sorafenib and diclofenac interrupts a positive feedback signaling loop involving extracellular signal–regulated kinase, cellular phospholipase A2, and COX. Genome-wide expression profiling shows synergy-specific downregulation of survival-related genes. This study has uncovered novel functional drug combinations and suggests that the underlying signaling networks that control responses to targeted agents can vary substantially, depending on unexplored components of the cell genotype. Mol Cancer Ther; 11(11); 2505–15. ©2012 AACR.
Data from Tenovin-D3, a Novel Small-Molecule Inhibitor of Sirtuin SirT2, Increases p21 (CDKN1A) Expression in a p53-Independent Manner
Authors: McCarthy Anna R. , Sachweh Marijke C.C. , Higgins Maureen , Campbell Johanna , Drummond Catherine J. , van Leeuwen Ingeborg M.M. , Pirrie Lisa , Ladds Marcus J.G.W. , Westwood Nicholas J. , Laín Sonia
Published: April 2023

Abstract
While small-molecule inhibitors of class I/II histone deacetylases (HDAC) have been approved for cancer treatment, inhibitors of the sirtuins (a family of class III HDACs) still require further validation and optimization to enter clinical trials. Recent studies show that tenovin-6, a small-molecule inhibitor of sirtuins SirT1 and SirT2, reduces tumor growth in vivo and eliminates leukemic stem cells in a murine model for chronic myelogenous leukemia. Here, we describe a tenovin analogue, tenovin-D3, that preferentially inhibits sirtuin SirT2 and induces predicted phenotypes for SirT2 inhibition. Unlike tenovin-6 and in agreement with its weak effect on SirT1 (a p53 deacetylase), tenovin-D3 fails to increase p53 levels or transcription factor activity. However, tenovin-D3 promotes expression of the cell-cycle regulator and p53 target p21WAF1/CIP1 (CDKN1A) in a p53-independent manner. Structure–activity relationship studies strongly support that the ability of tenovin-D3 to inhibit SirT2 contributes to this p53-independent induction of p21. The ability of tenovin-D3 to increase p21 mRNA and protein levels is shared with class I/II HDAC inhibitors currently used in the clinic and therefore suggests that SirT2 inhibition and class I/II HDAC inhibitors have similar effects on cell-cycle progression. Mol Cancer Ther; 12(4); 352–60. ©2013 AACR.
Data from A Systems Biology Approach Identifies SART1 as a Novel Determinant of Both 5-Fluorouracil and SN38 Drug Resistance in Colorectal Cancer
Authors: Allen Wendy L. , Stevenson Leanne , Coyle Vicky M. , Jithesh Puthen V. , Proutski Irina , Carson Gail , Gordon Michael A. , Lenz Heinz-Josef D. , Van Schaeybroeck Sandra , Longley Daniel B. , Johnston Patrick G.
Published: April 2023

Abstract
Chemotherapy response rates for advanced colorectal cancer remain disappointingly low, primarily because of drug resistance, so there is an urgent need to improve current treatment strategies. To identify novel determinants of resistance to the clinically relevant drugs 5-fluorouracil (5-FU) and SN38 (the active metabolite of irinotecan), transcriptional profiling experiments were carried out on pretreatment metastatic colorectal cancer biopsies and HCT116 parental and chemotherapy-resistant cell line models using a disease-specific DNA microarray. To enrich for potential chemoresistance-determining genes, an unsupervised bioinformatics approach was used, and 50 genes were selected and then functionally assessed using custom-designed short interfering RNA (siRNA) screens. In the primary siRNA screen, silencing of 21 genes sensitized HCT116 cells to either 5-FU or SN38 treatment. Three genes (RAPGEF2, PTRF, and SART1) were selected for further analysis in a panel of 5 colorectal cancer cell lines. Silencing SART1 sensitized all 5 cell lines to 5-FU treatment and 4/5 cell lines to SN38 treatment. However, silencing of RAPGEF2 or PTRF had no significant effect on 5-FU or SN38 sensitivity in the wider cell line panel. Further functional analysis of SART1 showed that its silencing induced apoptosis that was caspase-8 dependent. Furthermore, silencing of SART1 led to a downregulation of the caspase-8 inhibitor, c-FLIP, which we have previously shown is a key determinant of drug resistance in colorectal cancer. This study shows the power of systems biology approaches for identifying novel genes that regulate drug resistance and identifies SART1 as a previously unidentified regulator of c-FLIP and drug-induced activation of caspase-8. Mol Cancer Ther; 11(1); 119–31. ©2011 AACR.
Data from Targeting the Glyoxalase Pathway Enhances TRAIL Efficacy in Cancer Cells by Downregulating the Expression of Antiapoptotic Molecules
Authors: Taniguchi Hiroya , Horinaka Mano , Yoshida Tatsushi , Yano Kimihiro , Goda Ahmed E. , Yasuda Shusuke , Wakada Miki , Sakai Toshiyuki
Published: April 2023

Abstract
Methylglyoxal is an essential component in glycolysis and is known to be an inducer of apoptosis. Glyoxalase I (GLO1) metabolizes and inactivates methylglyoxal. GLO1 is known to be overexpressed in cancer cells and causes resistance to anticancer agents. We show for the first time that methylglyoxal treatment or the silencing of GLO1 enhances sensitivity to the promising anticancer agent TRAIL in malignant tumor cells. Methylglyoxal suppressed the expression of antiapoptotic factors, X-linked inhibitor of apoptosis protein (XIAP), survivin, cIAP1, Bcl-2, and Bcl-xL, without affecting TRAIL receptors, DR4 and DR5. Knockdown of XIAP or survivin by siRNA also enhanced TRAIL-induced apoptosis, indicating that downregulation of XIAP and survivin expression by methylglyoxal contributes to the enhancement of TRAIL activity. Furthermore, methylglyoxal decreased NF-κB activity with or without TRAIL treatment. On the other hand, the knockdown of GLO1 by siRNA enhanced TRAIL-induced apoptosis via the downregulation of XIAP and survivin expression. In conclusion, our results strongly suggest that sensitivity to TRAIL is increased by inhibition of the glyoxalase pathway and that the combination of TRAIL with methylglyoxal or glyoxalase inhibitors may be useful for a novel combination chemotherapy. Mol Cancer Ther; 11(10); 2294–300. ©2012 AACR.
Data from Histone Deacetylase Regulation of ATM-Mediated DNA Damage Signaling
Authors: Thurn K. Ted , Thomas Scott , Raha Paromita , Qureshi Ian , Munster Pamela N.
Published: April 2023

Abstract
Ataxia–telangiectasia mutated (ATM) is a major regulator of the DNA damage response. ATM promotes the activation of BRCA1, CHK2, and p53 leading to the induction of response genes such as CDKN1A (p21), GADD45A, and RRM2B that promote cell-cycle arrest and DNA repair. The upregulation of these response genes may contribute to resistance of cancer cells to genotoxic therapies. Here, we show that histone deacetylases (HDAC) play a major role in mitigating the response of the ATM pathway to DNA damage. HDAC inhibition decreased ATM activation and expression, and attenuated the activation of p53 in vitro and in vivo. Select depletion of HDAC1 and HDAC2 was sufficient to modulate ATM activation, reduce GADD45A and RRM2B induction, and increase sensitivity to DNA strand breaks. The regulation of ATM by HDAC enzymes therefore suggests a vital role for HDAC1 and HDAC2 in the DNA damage response, and the potential use of the ATM pathway as a pharmacodynamic marker for combination therapies involving HDAC inhibitors. Mol Cancer Ther; 12(10); 2078–87. ©2013 AACR.
Data from TAK-960, a Novel, Orally Available, Selective Inhibitor of Polo-Like Kinase 1, Shows Broad-spectrum Preclinical Antitumor Activity in Multiple Dosing Regimens
Authors: Hikichi Yuichi , Honda Kohei , Hikami Kouki , Miyashita Hitoshi , Kaieda Isao , Murai Saomi , Uchiyama Noriko , Hasegawa Maki , Kawamoto Tomohiro , Sato Takashi , Ichikawa Takashi , Cao Sheldon , Nie Zhe , Zhang Lilly , Yang Johnny , Kuida Keisuke , Kupperman Erik
Published: April 2023

Abstract
Polo-like kinase 1 (PLK1) is a serine/threonine protein kinase involved in key processes during mitosis. Human PLK1 has been shown to be overexpressed in various human cancers, and elevated levels of PLK1 have been associated with poor prognosis, making it an attractive target for anticancer therapy. TAK-960 [4-[(9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepin-2-yl)amino]-2-fluoro-5-methoxy-N-(1-methylpiperidin-4-yl) benzamide] is a novel, investigational, orally bioavailable, potent, and selective PLK1 inhibitor that has shown activity in several tumor cell lines, including those that express multidrug-resistant protein 1 (MDR1). Consistent with PLK1 inhibition, TAK-960 treatment caused accumulation of G2–M cells, aberrant polo mitosis morphology, and increased phosphorylation of histone H3 (pHH3) in vitro and in vivo. TAK-960 inhibited proliferation of multiple cancer cell lines, with mean EC50 values ranging from 8.4 to 46.9 nmol/L, but not in nondividing normal cells (EC50 >1,000 nmol/L). The mutation status of TP53 or KRAS and MDR1 expression did not correlate with the potency of TAK-960 in the cell lines tested. In animal models, oral administration of TAK-960 increased pHH3 in a dose-dependent manner and significantly inhibited the growth of HT-29 colorectal cancer xenografts. Treatment with once daily TAK-960 exhibited significant efficacy against multiple tumor xenografts, including an adriamycin/paclitaxel-resistant xenograft model and a disseminated leukemia model. TAK-960 has entered clinical evaluation in patients with advanced cancers. Mol Cancer Ther; 11(3); 700–9. ©2011 AACR.
Data from Mechanism of Drug Efficacy Within the EGF Receptor Revealed by Microsecond Molecular Dynamics Simulation
Authors: Wan Shunzhou , Wright David W. , Coveney Peter V.
Published: April 2023

Abstract
The EGF receptor (EGFR) regulates important cellular processes including proliferation, differentiation, and apoptosis. EGFR is frequently overexpressed in a range of cancers and is associated with disease progression and treatment. Clinical studies have shown that EGFR mutations confer tumor sensitivity to tyrosine kinase inhibitors in patients with non–small cell lung cancer. In this study, we have conducted molecular dynamics simulations over several microseconds for wild-type and L858R mutant forms of EGFR in the ligand-free state. Close inspection of the conformations and interactions within the binding pocket reveals, converse to the wild type, that the mutant EGFR prefers to bind gefitinib, a targeted anticancer drug, rather than ATP, offering an explanation for why gefitinib is more effective in patients with EGFR mutations than those without. Mol Cancer Ther; 11(11); 2394–400. ©2012 AACR.
Data from MET Activation Mediates Resistance to Lapatinib Inhibition of HER2-Amplified Gastric Cancer Cells
Authors: Chen Chin-Tung , Kim Hyaehwan , Liska David , Gao Sizhi , Christensen James G. , Weiser Martin R.
Published: April 2023

Abstract
HER2 amplification is found in more than 15% of gastric cancers and is associated with poor clinical outcome. Lapatinib, a dual HER2 and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, has shown promising in vitro results in treating HER2+ cancer cells. However, several studies have shown that activation of alternative receptor tyrosine kinases can mediate resistance to HER-targeted therapy. Here, we investigated whether activated MET can confer resistance to lapatinib inhibition of gastric cancer cells. A panel of gastric cancer cell lines was treated with lapatinib, and we observed that cell proliferation was reduced by 70% and that the degree of HER2 amplification corresponds to sensitivity to lapatinib. Immunoblotting analysis indicated that phosphorylation of HER2, EGFR, MET, AKT, and extracellular signal-regulated kinase was inhibited by lapatinib and presumably led to cell-cycle arrest as observed with flow cytometry. Hepatocyte growth factor (HGF) activation of MET receptors rescued cells from lapatinib-induced growth inhibition by restimulating the downstream pathways and restoring normal cell-cycle progression. This rescue effect could be abrogated by inhibiting MET with PHA-665752 (a highly specific MET inhibitor) or downregulating MET expression with short interfering RNA. No synergy in growth inhibition was observed when cells were treated with a combination of lapatinib and PHA-665752. Repeat studies using insulin-like growth factor 1 and fibroblast growth factor 3 could not uniformly rescue the lapatinib-treated gastric cancer cells. In conclusion, HGF/MET–mediated resistance to lapatinib is a novel mechanism of resistance to HER2-targeted agents in gastric cancer cells. Development of inhibitors targeting multiple receptors or common downstream signaling proteins merits further investigation. Mol Cancer Ther; 11(3); 660–9. ©2012 AACR.
Data from The EGFR T790M Mutation in Acquired Resistance to an Irreversible Second-Generation EGFR Inhibitor
Authors: Kim Youngwook , Ko Jeonghun , Cui ZhengYun , Abolhoda Amir , Ahn Jin Seok , Ou Sai-Hong , Ahn Myung-Ju , Park Keunchil
Published: April 2023

Abstract
Molecular target therapies using first-generation, reversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI), such as gefitinib or erlotinib, have been shown to be effective for patients with non-small cell lung cancer (NSCLC) who harbor activating mutations in EGFR. However, these patients eventually develop resistance to the reversible TKIs, and this has led to the development of second-generation, irreversible EGFR inhibitors. Currently, the mechanism of acquired resistance to irreversible EGFR inhibitors is not clear. Using an in vitro cell culture system, we modeled the acquired resistance to first-line treatment with second-generation EGFR-TKIs using an EGFR-mutant NSCLC cell line. Here, we report a mechanism of resistance involving T790M secondary mutation as well as a corresponding clinical case. The results of these findings suggest that inhibition of EGFR by currently available second-generation EGFR-TKIs may not be sufficient to physiologically prevent the emergence of cells that are still dependent on EGFR signaling. This finding bears important implications on the limitations of currently available second-generation EGFR-TKIs. Mol Cancer Ther; 11(3); 784–91. ©2012 AACR.
Data from Targeting TRAIL Death Receptor 4 with Trivalent DR4 Atrimer Complexes
Authors: Allen Joshua E. , Ferrini Roger , Dicker David T. , Batzer Glenda , Chen Elise , Oltean Daniela I. , Lin Bing , Renshaw Mark W. , Kretz-Rommel Anke , El-Deiry Wafik S.
Published: April 2023

Abstract
TRAIL is a trimeric protein that potently induces apoptosis in cancer cells by binding to the trimeric death receptors (DR4 or DR5). Death receptors are attractive therapeutic targets through both the recombinant TRAIL ligand as well as receptor agonist monoclonal antibodies. Although efficacy of the ligand is hampered by its short half-life, agonistic antibodies have a much longer half-life and have shown some clinical efficacy as antitumor agents. However, the efficacy of these antibodies may be limited by their bivalent nature that does not optimally mimic the trimeric ligand. To overcome limitations of currently used death receptor-targeting agents, we engineered trimeric proteins called Atrimer complexes that selectively bind DR4 and potently induce apoptosis in a variety of cancer cells. Atrimer complexes are based on human tetranectin, a trimeric plasma protein of approximately 60 kDa. Loop regions within the tetranectin C-type lectin domains (CTLD) were randomized to create a large phage display library that was used to select DR4-binding complexes. A panel of unique and potent agonist DR4 Atrimer complexes with subnanomolar affinity to DR4 and no detectable binding to DR5 or the decoy receptors was identified. Mechanism of action studies with a selected Atrimer complex, 1G2, showed that Atrimer complexes induce caspase-dependent and DR4-specific apoptosis in cancer cells while sparing normal human fibroblasts and, importantly, hepatocytes. This proof-of-principle study supports the use of alternative proteins engineered to overcome limitations of therapeutically desirable molecules such as TRAIL. Mol Cancer Ther; 11(10); 2087–95. ©2012 AACR.
Data from Identification and Characterization of NVP-BKM120, an Orally Available Pan-Class I PI3-Kinase Inhibitor
Authors: Maira Sauveur-Michel , Pecchi Sabina , Huang Alan , Burger Matthew , Knapp Mark , Sterker Dario , Schnell Christian , Guthy Daniel , Nagel Tobi , Wiesmann Marion , Brachmann Saskia , Fritsch Christine , Dorsch Marion , Chène Patrick , Shoemaker Kevin , De Pover Alain , Menezes Daniel , Martiny-Baron Georg , Fabbro Doriano , Wilson Christopher J. , Schlegel Robert , Hofmann Francesco , García-Echeverría Carlos , Sellers William R. , Voliva Charles F.
Published: April 2023

Abstract
Following the discovery of NVP-BEZ235, our first dual pan-PI3K/mTOR clinical compound, we sought to identify additional phosphoinositide 3-kinase (PI3K) inhibitors from different chemical classes with a different selectivity profile. The key to achieve these objectives was to couple a structure-based design approach with intensive pharmacologic evaluation of selected compounds during the medicinal chemistry optimization process. Here, we report on the biologic characterization of the 2-morpholino pyrimidine derivative pan-PI3K inhibitor NVP-BKM120. This compound inhibits all four class I PI3K isoforms in biochemical assays with at least 50-fold selectivity against other protein kinases. The compound is also active against the most common somatic PI3Kα mutations but does not significantly inhibit the related class III (Vps34) and class IV (mTOR, DNA-PK) PI3K kinases. Consistent with its mechanism of action, NVP-BKM120 decreases the cellular levels of p-Akt in mechanistic models and relevant tumor cell lines, as well as downstream effectors in a concentration-dependent and pathway-specific manner. Tested in a panel of 353 cell lines, NVP-BKM120 exhibited preferential inhibition of tumor cells bearing PIK3CA mutations, in contrast to either KRAS or PTEN mutant models. NVP-BKM120 shows dose-dependent in vivo pharmacodynamic activity as measured by significant inhibition of p-Akt and tumor growth inhibition in mechanistic xenograft models. NVP-BKM120 behaves synergistically when combined with either targeted agents such as MEK or HER2 inhibitors or with cytotoxic agents such as docetaxel or temozolomide. The pharmacological, biologic, and preclinical safety profile of NVP-BKM120 supports its clinical development and the compound is undergoing phase II clinical trials in patients with cancer. Mol Cancer Ther; 11(2); 317–28. ©2011 AACR.
Data from Inhibition of Monocarboxylate Transporter 2 Induces Senescence-Associated Mitochondrial Dysfunction and Suppresses Progression of Colorectal Malignancies In Vivo
Authors: Lee Inkyoung , Lee Sook-Ja , Kang Won Ki , Park Chaehwa
Published: April 2023

Abstract
Senescence, an inherent tumor suppressive mechanism, is a critical determinant for chemotherapy. In the present study, we show that the monocarboxylate transporter 2 (MCT2) protein was tumor-selectively expressed in human colorectal malignancies and knockdown of MCT2 induces mitochondrial dysfunction, cell-cycle arrest, and senescence without additional cellular stress in colorectal cancer cell lines. Moreover, the reactive oxygen species (ROS) scavenger, N-acetylcysteine, blocked MCT2 knockdown-induced growth arrest and cellular senescence, indicating a pivotal role of ROS in this pathway. Dramatic induction of mitochondrial superoxide generation and decrease in ATP production was observed, indicating that mitochondrial dysfunction is the major mechanism underlying MCT2 knockdown-induced ROS generation. Senescence-associated DNA damage was also evident from the increase in promyelocytic leukemia bodies, γH2AX foci, and SAHF. Conversely, overexpression of MCT2 prevented doxorubicin-induced ROS accumulation (P = 0.0002) and cell growth inhibition (P = 0.001). MCT2 knockdown suppressed KRAS mutant colorectal tumor growth in vivo. In addition, MCT2 knockdown and cytostatic drug combination further enhanced the antitumor effect. These findings support the use of MCT2 as a promising target for inhibition of colorectal cancer. Mol Cancer Ther; 11(11); 2342–51. ©2012 AACR.
Data from The HSP70 and Autophagy Inhibitor Pifithrin-μ Enhances the Antitumor Effects of TRAIL on Human Pancreatic Cancer
Authors: Monma Hiroyuki , Harashima Nanae , Inao Touko , Okano Shinji , Tajima Yoshitsugu , Harada Mamoru
Published: April 2023

Abstract
TRAIL and agonistic death receptor-specific antibodies can induce apoptosis in cancer cells with little cytotoxicity to normal cells. To improve TRAIL-induced antitumor effects, we tested its effectiveness in combination with pifithrin (PFT)-μ, which has the potential to inhibit HSP70 function and autophagy, both of which participate in TRAIL resistance in cancer cells. Among the four human pancreatic cancer cell lines tested, MiaPaca-2, Panc-1, and BxPC-3 cells showed varying sensitivities to TRAIL. In MiaPaca-2 and Panc-1 cells, knockdown of HSP70 or beclin-1, the latter an autophagy-related molecule, by RNA interference augmented TRAIL-induced antitumor effects, decreasing cell viability, and increasing apoptosis. On the basis of these findings, we next determined whether the TRAIL-induced antitumor effects could be augmented by its combination with PFT-μ. The combination of TRAIL plus PFT-μ significantly decreased the viability and colony-forming ability of MiaPaca-2 and Panc-1 cells compared with cells treated with either agent alone. When applied alone, PFT-μ increased Annexin V+ cells in both caspase-dependent and -independent manners. It also promoted TRAIL-induced apoptosis and arrested cancer cell growth. Furthermore, PFT-μ antagonized TRAIL-associated NF-κB activation in cancer cells. In a xenograft mouse model, combination therapy significantly inhibited MiaPaca-2 tumor growth compared with treatment with either agent alone. The results of this study suggest protective roles for HSP70 and autophagy in TRAIL resistance in pancreatic cancer cells and suggest that PFT-μ is a promising agent for use in therapies intended to enhance the antitumor effects of TRAIL. Mol Cancer Ther; 12(4); 341–51. ©2013 AACR.
Data from A Second-Generation 2-Methoxyestradiol Prodrug Is Effective against Barrett's Adenocarcinoma in a Mouse Xenograft Model
Authors: Kambhampati Suman , Rajewski Roger A. , Tanol Mehmet , Haque Inamul , Das Amlan , Banerjee Snigdha , Jha Saheli , Burns Douglas , Borrego-Diaz Emma , Van Veldhuizen Peter J. , Banerjee Sushanta K.
Published: April 2023

Abstract
2-Methoxyestradiol (2-ME2) is an endogenous metabolite of estradiol. In preclinical models, 2-ME2 is effective against different types of tumors. Unfortunately, only low systemic concentrations of 2-ME2 can be achieved following oral administration, even after very high doses are administered to patients. In an effort to solve this problem, we have now synthesized and tested a new prodrug of 2-ME2 that is water-soluble due to a bioreversible hydrophilic group added at the 3-position and that more effectively resists metabolic inactivation due to an ester moiety added to mask the 17-position alcohol. We are reporting here for the first time that this double prodrug of 2-ME2 is effective as an antiproliferative and anticancer agent for both in vitro and in vivo studies against Barrett esophageal adenocarcinoma (BEAC) and provided greater potency than 2-ME2 in inhibiting the growth of BEAC xenografts. Finally, studies indicate that, like 2-ME2, the 2-ME2-PD1 exhibits anticancer effect through possible disruption of microtubule network. Mol Cancer Ther; 12(3); 255–63. ©2012 AACR.
Data from Molecular and Cellular Pharmacology of the Hypoxia-Activated Prodrug TH-302
Authors: Meng Fanying , Evans James W. , Bhupathi Deepthi , Banica Monica , Lan Leslie , Lorente Gustavo , Duan Jian-Xin , Cai Xiaohong , Mowday Alexandra M. , Guise Christopher P. , Maroz Andrej , Anderson Robert F. , Patterson Adam V. , Stachelek Gregory C. , Glazer Peter M. , Matteucci Mark D. , Hart Charles P.
Published: April 2023

Abstract
TH-302 is a 2-nitroimidazole triggered hypoxia-activated prodrug (HAP) of bromo-isophosphoramide mustard currently undergoing clinical evaluation. Here, we describe broad-spectrum activity, hypoxia-selective activation, and mechanism of action of TH-302. The concentration and time dependence of TH-302 activation was examined as a function of oxygen concentration, with reference to the prototypic HAP tirapazamine, and showed superior oxygen inhibition of cytotoxicity and much improved dose potency relative to tirapazamine. Enhanced TH-302 cytotoxicity under hypoxia was observed across 32 human cancer cell lines. One-electron reductive enzyme dependence was confirmed using cells overexpressing human NADPH:cytochrome P450 oxidoreductase and radiolytic reduction established the single-electron stoichiometry of TH-302 fragmentation (activation). Examining downstream effects of TH-302 activity, we observed hypoxia-dependent induction of γH2AX phosphorylation, DNA cross-linking, and cell-cycle arrest. We used Chinese hamster ovary cell–based DNA repair mutant cell lines and established that lines deficient in homology-dependent repair, but not lines deficient in base excision, nucleotide excision, or nonhomologous end-joining repair, exhibited marked sensitivity to TH-302 under hypoxia. Consistent with this finding, enhanced sensitivity to TH-302 was also observed in lines deficient in BRCA1, BRCA2, and FANCA. Finally, we characterized TH-302 activity in the three-dimensional tumor spheroid and multicellular layer models. TH-302 showed much enhanced potency in H460 spheroids compared with H460 monolayer cells under normoxia. Multicellular layers composed of mixtures of parental HCT116 cells and HCT116 cells engineered to express an oxygen-insensitive bacterial nitroreductase showed that TH-302 exhibits a significant bystander effect. Mol Cancer Ther; 11(3); 740–51. ©2011 AACR.
Data from Redirecting Apoptosis to Aponecrosis Induces Selective Cytotoxicity to Pancreatic Cancer Cells through Increased ROS, Decline in ATP Levels, and VDAC
Authors: Dinnen Richard D. , Mao Yuehua , Qiu Wanglong , Cassai Nicholas , Slavkovich Vesna N. , Nichols Gwen , Su Gloria H. , Brandt-Rauf Paul , Fine Robert L.
Published: April 2023

Abstract
Pancreatic cancer cell lines with mutated ras underwent an alternative form of cell death (aponecrosis) when treated concomitantly with clinically achievable concentrations of arsenic trioxide, ascorbic acid, and disulfiram (Antabuse; AAA). AAA's major effects are mediated through generation of intracellular reactive oxygen species (ROS) and more than 50% decline in intracellular ATP. N-acetyl cysteine and a superoxide dismutase mimetic prevented aponecrosis and restored intracellular ATP levels. DIDS (4,4′-diisothiocyanatostilbene-2, 2′ disulfonic acid), the pan- Voltage-Dependent Anion Channel (VDAC), -1, 2, 3 inhibitor and short hairpin RNA (shRNA) to VDAC-1 blocked cell death and ROS accumulation. In vivo exposure of AAA led to a 62% reduction in mean tumor size and eliminated tumors in 30% of nude mice with PANC-1 xenografts. We concluded that early caspase-independent apoptosis was shifted to VDAC-mediated “targeted” aponecrosis by the addition of disulfiram to arsenic trioxide and ascorbic acid. Conceptually, this work represents a paradigm shift where switching from apoptosis to aponecrosis death pathways, also known as targeted aponecrosis, could be utilized to selectively kill pancreatic cancer cells resistant to apoptosis. Mol Cancer Ther; 12(12); 2792–803. ©2013 AACR.
Data from The HSP90 Inhibitor, AT13387, Is Effective against Imatinib-Sensitive and -Resistant Gastrointestinal Stromal Tumor Models
Authors: Smyth Tomoko , Van Looy Thomas , Curry Jayne E. , Rodriguez-Lopez Ana M. , Wozniak Agnieszka , Zhu Meijun , Donsky Rachel , Morgan Jennifer G. , Mayeda Mark , Fletcher Jonathan A. , Schöffski Patrick , Lyons John , Thompson Neil T. , Wallis Nicola G.
Published: April 2023

Abstract
The majority of gastrointestinal stromal tumors (GIST) are characterized by activating mutations of KIT, an HSP90 client protein. Further secondary resistance mutations within KIT limit clinical responses to tyrosine kinase inhibitors, such as imatinib. The dependence of KIT and its mutated forms on HSP90 suggests that HSP90 inhibition might be a valuable treatment option for GIST, which would be equally effective on imatinib-sensitive and -resistant clones. We investigated the activity of AT13387, a potent HSP90 inhibitor currently being evaluated in clinical trials, in both in vitro and in vivo GIST models. AT13387 inhibited the proliferation of imatinib-sensitive (GIST882, GIST-T1) and -resistant (GIST430, GIST48) cell lines, including those resistant to the geldanamycin analogue HSP90 inhibitor, 17-AAG. Treatment with AT13387 resulted in depletion of HSP90 client proteins, KIT and AKT, along with their phospho-forms in imatinib-sensitive and -resistant cell lines, irrespective of KIT mutation. KIT signaling was ablated, whereas HSP70, a marker of HSP90 inhibition, was induced. In vivo, antitumor activity of AT13387 was showed in both the imatinib-sensitive, GIST-PSW, xenograft model and a newly characterized imatinib-resistant, GIST430, xenograft model. Induction of HSP70, depletion of phospho-KIT and inhibition of KIT signaling were seen in tumors from both models after treatment with AT13387. A combination of imatinib and AT13387 treatment in the imatinib-resistant GIST430 model significantly enhanced tumor growth inhibition over either of the monotherapies. Importantly, the combination of AT13387 and imatinib was well tolerated. These results suggest AT13387 is an excellent candidate for clinical testing in GIST in combination with imatinib. Mol Cancer Ther; 11(8); 1799–808. ©2012 AACR.
Data from The Aurora Kinase A Inhibitor MLN8237 Enhances Cisplatin-Induced Cell Death in Esophageal Adenocarcinoma Cells
Authors: Sehdev Vikas , Peng DunFa , Soutto Mohammed , Washington M. Kay , Revetta Frank , Ecsedy Jeffrey , Zaika Alexander , Rau Tilman T. , Schneider-Stock Regine , Belkhiri Abbes , El-Rifai Wael
Published: April 2023

Abstract
Esophageal adenocarcinomas are poorly responsive to chemotherapeutics. This study aimed to determine the levels of Aurora kinase A (AURKA) and the therapeutic potential of MLN8237, an investigational AURKA inhibitor, alone and in combination with cisplatin. Using quantitative real-time PCR, we detected frequent AURKA gene amplification (15 of 34, 44%) and mRNA overexpression (37 of 44, 84%) in esophageal adenocarcinomas (P < 0.01). Immunohistochemical analysis showed overexpression of AURKA in more than two-thirds of esophageal adenocarcinoma tissue samples (92 of 132, 70%; P < 0.001). Using FLO-1, OE19, and OE33 esophageal adenocarinoma cell lines, with constitutive AURKA overexpression and mutant p53, we observed inhibition of colony formation with a single treatment of 0.5 μmol/L MLN8237 (P < 0.05). This effect was further enhanced in combination with 2.5 μmol/L cisplatin (P < 0.001). Twenty-four hours after treatment with the MLN8237 or MLN8237 and cisplatin, cell-cycle analyses showed a sharp increase in the percentage of polyploid cells (P < 0.001). This was followed by an increase in the percentage of cells in the sub-G1 phase at 72 hours, concordant with the occurrence of cell death (P < 0.001). Western blot analysis showed higher induction of TAp73β, PUMA, NOXA, cleaved caspase-3, and cleaved PARP with the combined treatment, as compared with a single-agent treatment. Using xenograft models, we showed an enhanced antitumor role for the MLN8237 and cisplatin combination, as compared with single-agent treatments (P < 0.001). In conclusion, this study shows frequent overexpression of AURKA and suggests that MLN8237 could be an effective antitumor agent, which can be combined with cisplatin for a better therapeutic outcome in esophageal adenocarcinomas. Mol Cancer Ther; 11(3); 763–74. ©2012 AACR.
Data from Dual HER/VEGF Receptor Targeting Inhibits In Vivo Ovarian Cancer Tumor Growth
Authors: Becker Marc A. , Farzan Thahir , Harrington Sean C. , Krempski James W. , Weroha S. John , Hou Xiaonan , Kalli Kimberly R. , Wong Tai W. , Haluska Paul
Published: April 2023

Abstract
Ovarian cancer mortality ranks highest among all gynecologic cancers with growth factor pathways playing an integral role in tumorigenesis, metastatic dissemination, and therapeutic resistance. The HER and VEGF receptor (VEGFR) are both overexpressed and/or aberrantly activated in subsets of ovarian tumors. While agents targeting either the HER or VEGF pathways alone have been investigated, the impact of these agents have not led to overall survival benefit in ovarian cancer. We tested the hypothesis that cotargeting HER and VEGFR would maximize antitumor efficacy at tolerable doses. To this end, ovarian cancer xenografts grown intraperitoneally in athymic nude mice were tested in response to AC480 (pan-HER inhibitor, “HERi”), cediranib (pan-VEGFR inhibitor “VEGFRi”), or BMS-690514 (combined HER/VEGFR inhibitor “EVRi”). EVRi was superior to both HERi and VEGFRi in terms of tumor growth, final tumor weight, and progression-free survival. Correlative tumor studies employing phosphoproteomic antibody arrays revealed distinct agent-specific alterations, with EVRi inducing the greatest overall effect on growth factor signaling. These data suggest that simultaneous inhibition of HER and VEGFR may benefit select subsets of ovarian cancer tumors. To this end, we derived a novel HER/VEGF signature that correlated with poor overall survival in high-grade, late stage, serous ovarian cancer patient tumors. Mol Cancer Ther; 12(12); 2909–16. ©2013 AACR.
Data from Perillyl Alcohol for the Treatment of Temozolomide-Resistant Gliomas
Authors: Cho Hee-Yeon , Wang Weijun , Jhaveri Niyati , Torres Shering , Tseng Joshua , Leong Michelle N. , Lee David Jungpa , Goldkorn Amir , Xu Tong , Petasis Nicos A. , Louie Stan G. , Schönthal Axel H. , Hofman Florence M. , Chen Thomas C.
Published: April 2023

Abstract
Perillyl alcohol (POH) is a monoterpene that has been used orally for the treatment of systemic cancer. However, when used orally significant gastrointestinal side effects and lack of overall efficacy were documented. Recently, in a phase II trial in Brazil for the treatment of temozolomide (TMZ)-resistant malignant gliomas, POH was well tolerated when administered intranasally. The present study explores the effects and mechanisms of POH on TMZ-sensitive and TMZ-resistant glioma cells. In vitro studies showed that POH was cytotoxic to TMZ-resistant as well as TMZ-sensitive glioma cells, and this effect was independent of O6-methylguanine-DNA methyltransferase expression. POH induced cytotoxicity, in part, through the endoplasmic reticulum (ER) stress pathway as shown by the increased expression of glucose-regulated protein-78 (GRP78), activating transcription factor 3, and C/EBP-homologous protein. In addition, POH impeded survival pathways, such as mTOR and Ras. As well, POH reduced the invasive capacity of sensitive and resistant glioma cells. POH alone and/or in combination with other ER stress–inducing cytotoxic drugs (i.e., 2, 5-dimethyl-celecoxib, nelfinavir) further induced apoptosis in TMZ-sensitive and TMZ-resistant glioma cells. To show whether intranasal delivery of POH was effective for the treatment of TMZ-resistant gliomas, animals bearing intracranial tumors were given POH intranasally. Animals treated through intranasal administration of POH exhibited a decrease in tumor growth and an increase in survival. Our data show that POH is an effective anti-glioma cytotoxic agent for TMZ-resistant gliomas when administered intranasally. Mol Cancer Ther; 11(11); 2462–72. ©2012 AACR.