bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Bcl-2/Bcl-xL Inhibition Increases the Efficacy of MEK Inhibition Alone and in Combination with PI3 Kinase Inhibition in Lung and Pancreatic Tumor Models
Authors: Tan Nguyen , Wong Maureen , Nannini Michelle A. , Hong Rebecca , Lee Leslie B. , Price Stephen , Williams Karen , Savy Pierre Pascal , Yue Peng , Sampath Deepak , Settleman Jeffrey , Fairbrother Wayne J. , Belmont Lisa D.
Published: April 2023

Abstract
Although mitogen-activated protein (MAP)–extracellular signal-regulated kinase (ERK) kinase (MEK) inhibition is predicted to cause cell death by stabilization of the proapoptotic BH3-only protein BIM, the induction of apoptosis is often modest. To determine if addition of a Bcl-2 family inhibitor could increase the efficacy of a MEK inhibitor, we evaluated a panel of 53 non–small cell lung cancer and pancreatic cancer cell lines with the combination of navitoclax (ABT-263), a Bcl-2/Bcl-xL (BCL2/BCL2L1) antagonist, and a novel MAP kinase (MEK) inhibitor, G-963. The combination is synergistic in the majority of lines, with an enrichment of cell lines harboring KRAS mutations in the high synergy group. Cells exposed to G-963 arrest in G1 and a small fraction undergo apoptosis. The addition of navitoclax to G-963 does not alter the kinetics of cell-cycle arrest, but greatly increases the percentage of cells that undergo apoptosis. The G-963/navitoclax combination was more effective than either single agent in the KRAS mutant H2122 xenograft model; BIM stabilization and PARP cleavage were observed in tumors, consistent with the mechanism of action observed in cell culture. Addition of the phosphatidylinositol 3-kinase (PI3K, PIK3CA) inhibitor GDC-0941 to this treatment combination increases cell killing compared with double- or single-agent treatment. Taken together, these data suggest the efficacy of agents that target the MAPK and PI3K pathways can be improved by combination with a Bcl-2 family inhibitor. Mol Cancer Ther; 12(6); 853–64. ©2013 AACR.
Data from Discovery of a Novel Orally Active Small-Molecule gp130 Inhibitor for the Treatment of Ovarian Cancer
Authors: Xu Shili , Grande Fedora , Garofalo Antonio , Neamati Nouri
Published: April 2023

Abstract
Interleukin (IL)-6 and Stat3 play key roles in ovarian cancer progression. However, the role of glycoprotein 130 (gp130), the signal transducer of this signaling axis, is not well-established. Currently, there are no small-molecule inhibitors of gp130 under clinical development. In this study, we show that gp130 is an attractive drug target in ovarian cancer due to its role in promoting cancer progression via the activation of its downstream Stat3 signaling. We also present preclinical studies of SC144, the first-in-class orally active small-molecule gp130 inhibitor. SC144 shows greater potency in human ovarian cancer cell lines than in normal epithelial cells. SC144 binds gp130, induces gp130 phosphorylation (S782) and deglycosylation, abrogates Stat3 phosphorylation and nuclear translocation, and further inhibits the expression of downstream target genes. In addition, SC144 shows potent inhibition of gp130 ligand–triggered signaling. Oral administration of SC144 delays tumor growth in a mouse xenograft model of human ovarian cancer without significant toxicity to normal tissues. Mol Cancer Ther; 12(6); 937–49. ©2013 AACR.
Data from The CDK4/6 Inhibitor LY2835219 Overcomes Vemurafenib Resistance Resulting from MAPK Reactivation and Cyclin D1 Upregulation
Authors: Yadav Vipin , Burke Teresa F. , Huber Lysiane , Van Horn Robert D. , Zhang Youyan , Buchanan Sean G. , Chan Edward M. , Starling James J. , Beckmann Richard P. , Peng Sheng-Bin
Published: April 2023

Abstract
B-RAF selective inhibitors, including vemurafenib, were recently developed as effective therapies for melanoma patients with B-RAF V600E mutation. However, most patients treated with vemurafenib eventually develop resistance largely due to reactivation of MAPK signaling. Inhibitors of MAPK signaling, including MEK1/2 inhibitor trametinib, failed to show significant clinical benefit in patients with acquired resistance to vemurafenib. Here, we describe that cell lines with acquired resistance to vemurafenib show reactivation of MAPK signaling and upregulation of cyclin D1 and are sensitive to inhibition of LY2835219, a selective inhibitor of cyclin-dependent kinase (CDK) 4/6. LY2835219 was demonstrated to inhibit growth of melanoma A375 tumor xenografts and delay tumor recurrence in combination with vemurafenib. Furthermore, we developed an in vivo vemurafenib-resistant model by continuous administration of vemurafenib in A375 xenografts. Consistently, we found that MAPK is reactivated and cyclin D1 is elevated in vemurafenib-resistant tumors, as well as in the resistant cell lines derived from these tumors. Importantly, LY2835219 exhibited tumor growth regression in a vemurafenib-resistant model. Mechanistic analysis revealed that LY2835219 induced apoptotic cell death in a concentration-dependent manner in vemurafenib-resistant cells whereas it primarily mediated cell-cycle G1 arrest in the parental cells. Similarly, RNAi-mediated knockdown of cyclin D1 induced significantly higher rate of apoptosis in the resistant cells than in parental cells, suggesting that elevated cyclin D1 activity is important for the survival of vemurafenib-resistant cells. Altogether, we propose that targeting cyclin D1–CDK4/6 signaling by LY2835219 is an effective strategy to overcome MAPK-mediated resistance to B-RAF inhibitors in B-RAF V600E melanoma. Mol Cancer Ther; 13(10); 2253–63. ©2014 AACR.
Data from Preclinical Evaluation of a Novel RXR Agonist for the Treatment of Neuroblastoma
Authors: Waters Alicia M. , Stewart Jerry E. , Atigadda Venkatram R. , Mroczek-Musulman Elizabeth , Muccio Donald D. , Grubbs Clinton J. , Beierle Elizabeth A.
Published: April 2023

Abstract
Neuroblastoma remains a common cause of pediatric cancer deaths, especially for children who present with advanced stage or recurrent disease. Currently, retinoic acid therapy is used as maintenance treatment to induce differentiation and reduce tumor recurrence following induction therapy for neuroblastoma, but unavoidable side effects are seen. A novel retinoid, UAB30, has been shown to generate negligible toxicities. In the current study, we hypothesized that UAB30 would have a significant impact on multiple neuroblastoma cell lines in vitro and in vivo. Cellular survival, cell-cycle analysis, migration, and invasion were studied using AlamarBlue assays, FACS, and Transwell assays, respectively, in multiple cell lines following treatment with UAB30. In addition, an in vivo murine model of human neuroblastoma was utilized to study the effects of UAB30 upon tumor xenograft growth and animal survival. We successfully demonstrated decreased cellular survival, invasion, and migration, cell-cycle arrest, and increased apoptosis after treatment with UAB30. Furthermore, inhibition of tumor growth and increased survival was observed in a murine neuroblastoma xenograft model. The results of these in vitro and in vivo studies suggest a potential therapeutic role for the low toxicity synthetic retinoid X receptor selective agonist, UAB30, in neuroblastoma treatment. Mol Cancer Ther; 14(7); 1559–69. ©2015 AACR.
Data from EpCAM-Selective Elimination of Carcinoma Cells by a Novel MAP-Based Cytolytic Fusion Protein
Authors: Hristodorov Dmitrij , Amoury Manal , Mladenov Radoslav , Niesen Judith , Arens Katharina , Berges Nina , Hein Lea , Di Fiore Stefano , Pham Anh-Tuan , Huhn Michael , Helfrich Wijnand , Fischer Rainer , Thepen Theo , Barth Stefan
Published: April 2023

Abstract
In normal epithelia, the epithelial cell adhesion molecule (EpCAM) expression is relatively low and only present at the basolateral cell surface. In contrast, EpCAM is aberrantly overexpressed in various human carcinomas. Therefore, EpCAM is considered to be a highly promising target for antibody-based cancer immunotherapy. Here, we present a new and fully human cytolytic fusion protein (CFP), designated “anti–EpCAM(scFv)-MAP,” that is comprised of an EpCAM-specific antibody fragment (scFv) genetically fused to the microtubule-associated protein tau (MAP). Anti–EpCAM(scFv)-MAP shows potent EpCAM-restricted proapoptotic activity toward rapidly proliferating carcinoma cells. In vitro assays confirmed that treatment with anti–EpCAM(scFv)-MAP resulted in the colocalization and stabilization of microtubules, suggesting that this could be the potential mode of action. Dose-finding experiments indicated that anti–EpCAM(scFv)-MAP is well tolerated in mice. Using noninvasive far-red in vivo imaging in a tumor xenograft mouse model, we further demonstrated that anti–EpCAM(scFv)-MAP inhibited tumor growth in vivo. In conclusion, our data suggest that anti–EpCAM(scFv)-MAP may be of therapeutic value for the targeted elimination of EpCAM+ carcinomas. Mol Cancer Ther; 13(9); 2194–202. ©2014 AACR.
Data from The 1,2-Diaminocyclohexane Carrier Ligand in Oxaliplatin Induces p53-Dependent Transcriptional Repression of Factors Involved in Thymidylate Biosynthesis
Authors: Kiyonari Shinichi , Iimori Makoto , Matsuoka Kazuaki , Watanabe Sugiko , Morikawa-Ichinose Tomomi , Miura Daisuke , Niimi Shinichiro , Saeki Hiroshi , Tokunaga Eriko , Oki Eiji , Morita Masaru , Kadomatsu Kenji , Maehara Yoshihiko , Kitao Hiroyuki
Published: April 2023

Abstract
Platinum-based chemotherapeutic drugs are widely used as components of combination chemotherapy in the treatment of cancer. One such drug, oxaliplatin, exerts a synergistic effect against advanced colorectal cancer in combination with 5-fluorouracil (5-FU) and leucovorin. In the p53-proficient colorectal cancer cell line HCT116, oxaliplatin represses the expression of deoxyuridine triphosphatase (dUTPase), a ubiquitous pyrophosphatase that catalyzes the hydrolysis of dUTP to dUMP and inhibits dUTP-mediated cytotoxicity. However, the underlying mechanism of this activity has not been completely elucidated, and it remains unclear whether factors other than downregulation of dUTPase contribute to the synergistic effect of 5-FU and oxaliplatin. In this study, we found that oxaliplatin and dachplatin, platinum-based drugs containing the 1,2-diaminocyclohexane (DACH) carrier ligand, repressed the expression of nuclear isoform of dUTPase (DUT-N), whereas cisplatin and carboplatin did not. Oxaliplatin induced early p53 accumulation, upregulation of primary miR-34a transcript expression, and subsequent downregulation of E2F3 and E2F1. Nutlin-3a, which activates p53 nongenotoxically, had similar effects. Introduction of miR-34a mimic also repressed E2F1 and DUT-N expression, indicating that this miRNA plays a causative role. In addition to DUT-N, oxaliplatin repressed, in a p53-dependent manner, the expression of genes encoding enzymes involved in thymidylate biosynthesis. Consequently, oxaliplatin significantly decreased the level of dTTP in the dNTP pool in a p53-dependent manner. These data indicate that the DACH carrier ligand in oxaliplatin triggers signaling via the p53–miR-34a–E2F axis, leading to transcriptional regulation that ultimately results in accumulation of dUTP and reduced dTTP biosynthesis, potentially enhancing 5-FU cytotoxicity. Mol Cancer Ther; 14(10); 2332–42. ©2015 AACR.
Data from Monensin Inhibits Epidermal Growth Factor Receptor Trafficking and Activation: Synergistic Cytotoxicity in Combination with EGFR Inhibitors
Authors: Dayekh Khalil , Johnson-Obaseki Stephanie , Corsten Martin , Villeneuve Patrick J. , Sekhon Harmanjatinder S. , Weberpals Johanne I. , Dimitroulakos Jim
Published: April 2023

Abstract
Targeting the EGFR, with inhibitors such as erlotinib, represents a promising therapeutic option in advanced head and neck squamous cell carcinomas (HNSCC). However, they lack significant efficacy as single agents. Recently, we identified the ability of statins to induce synergistic cytotoxicity in HNSCC cells through targeting the activation and trafficking of the EGFR. However, in a phase I trial of rosuvastatin and erlotinib, statin-induced muscle pathology limited the usefulness of this approach. To overcome these toxicity limitations, we sought to uncover other potential combinations using a 1,200 compound screen of FDA-approved drugs. We identified monensin, a coccidial antibiotic, as synergistically enhancing the cytotoxicity of erlotinib in two cell line models of HNSCC, SCC9 and SCC25. Monensin treatment mimicked the inhibitory effects of statins on EGFR activation and downstream signaling. RNA-seq analysis of monensin-treated SCC25 cells demonstrated a wide array of cholesterol and lipid synthesis genes upregulated by this treatment similar to statin treatment. However, this pattern was not recapitulated in SCC9 cells as monensin specifically induced the expression of activation of transcription factor (ATF) 3, a key regulator of statin-induced apoptosis. This differential response was also demonstrated in monensin-treated ex vivo surgical tissues in which HMG-CoA reductase expression and ATF3 were either not induced, induced singly, or both induced together in a cohort of 10 patient samples, including four HNSCC. These results suggest the potential clinical utility of combining monensin with erlotinib in patients with HNSCC. Mol Cancer Ther; 13(11); 2559–71. ©2014 AACR.
Data from Small Molecule BMH-Compounds That Inhibit RNA Polymerase I and Cause Nucleolar Stress
Authors: Peltonen Karita , Colis Laureen , Liu Hester , Jäämaa Sari , Zhang Zhewei , af Hällström Taija , Moore Henna M. , Sirajuddin Paul , Laiho Marikki
Published: April 2023

Abstract
Activation of the p53 pathway has been considered a therapeutic strategy to target cancers. We have previously identified several p53-activating small molecules in a cell-based screen. Two of the compounds activated p53 by causing DNA damage, but this modality was absent in the other four. We recently showed that one of these, BMH-21, inhibits RNA polymerase I (Pol I) transcription, causes the degradation of Pol I catalytic subunit RPA194, and has potent anticancer activity. We show here that three remaining compounds in this screen, BMH-9, BMH-22, and BMH-23, cause reorganization of nucleolar marker proteins consistent with segregation of the nucleolus, a hallmark of Pol I transcription stress. Further, the compounds destabilize RPA194 in a proteasome-dependent manner and inhibit nascent rRNA synthesis and expression of the 45S rRNA precursor. BMH-9– and BMH-22–mediated nucleolar stress was detected in ex vivo–cultured human prostate tissues indicating good tissue bioactivity. Testing of closely related analogues showed that their activities were chemically constrained. Viability screen for BMH-9, BMH-22, and BMH-23 in the NCI60 cancer cell lines showed potent anticancer activity across many tumor types. Finally, we show that the Pol I transcription stress by BMH-9, BMH-22, and BMH-23 is independent of p53 function. These results highlight the dominant impact of Pol I transcription stress on p53 pathway activation and bring forward chemically novel lead molecules for Pol I inhibition, and, potentially, cancer targeting. Mol Cancer Ther; 13(11); 2537–46. ©2014 AACR.
Data from HMDB and 5-AzadC Combination Reverses Tumor Suppressor CCAAT/Enhancer-Binding Protein Delta to Strengthen the Death of Liver Cancer Cells
Authors: Li Chien-Feng , Tsai Hsin-Hwa , Ko Chiung-Yuan , Pan Yen-Chun , Yen Chia-Jui , Lai Hong-Yue , Yuh Chiou-Hwa , Wu Wan-Chen , Wang Ju-Ming
Published: April 2023

Abstract
Hepatocellular carcinoma (HCC) can arise from chronic inflammation due to viral infection, organ damage, drug toxicity, or alcohol abuse. Moreover, gene desensitization via aberrant CpG island methylation is a frequent epigenetic defect in HCC. However, the details of how inflammation is linked with epigenetic-mediated desensitization of tumor suppressor genes remains less investigated. In this study, we found that loss of CEBPD enhances the growth of liver cancer cells and is associated with the occurrence of liver cancers, as determined by the assessment of clinical specimens and in vivo animal models. Moreover, E2F1-regulated epigenetic axis attenuated CEBPD expression in liver cancer cells. CEBPD is responsive to the hydroxymethyldibenzoylmethane (HMDB)-induced p38/CREB pathway and plays an important role in the HMDB-induced apoptosis of cancer cells. Regarding depression of epigenetic effects to enhance HMDB-induced CEBPD expression, the combination of HMDB and 5-Aza-2′-deoxycytidine (5-AzadC) could enhance the death of liver cancer cells and reduce the tumor formation of Huh7 xenograft mice. In conclusion, these results suggest that CEBPD could be a useful diagnostic marker and therapeutic target in HCC. The results also reveal the therapeutic potential for low-dose 5-AzadC to enhance the HMDB-induced death of HCC cells. Mol Cancer Ther; 14(11); 2623–33. ©2015 AACR.
Data from A Novel Therapeutic Strategy to Rescue the Immune Effector Function of Proteolytically Inactivated Cancer Therapeutic Antibodies
Authors: Fan Xuejun , Brezski Randall J. , Deng Hui , Dhupkar Pooja M. , Shi Yun , Gonzalez Anneliese , Zhang Songlin , Rycyzyn Michael , Strohl William R. , Jordan Robert E. , Zhang Ningyan , An Zhiqiang
Published: April 2023

Abstract
Primary and acquired resistance to anticancer antibody immunotherapies presents significant clinical challenges. Here, we demonstrate that proteolytic inactivation of cancer-targeting antibodies is an unappreciated contributor to cancer immune evasion, and the finding presents novel opportunities for therapeutic intervention. A single peptide bond cleavage in the IgG1 hinge impairs cancer cell killing due to structural derangement of the Fc region. Hinge-cleaved trastuzumab gradually accumulated on the surfaces of HER2-expressing cancer cell lines in vitro, and was greatly accelerated when the cells were engineered to express the potent bacterial IgG-degrading proteinase (IdeS). Similar to cancer-related matrix metalloproteinases (MMP), IdeS exposes a hinge neoepitope that we have developed an antibody, mAb2095-2, to specifically target the epitope. In in vitro studies, mAb2095-2 restored the lost antibody-dependent cell-mediated cytotoxicity functionality of cell-bound single-cleaved trastuzumab (scIgG-T). In vivo, mAb2095-2 rescued the impaired Fc-dependent tumor-suppressive activity of scIgG-T in a xenograft tumor model and restored the recruitment of immune effector cells into the tumor microenvironment. More importantly, an Fc-engineered proteinase-resistant version of mAb2095-2 rescued trastuzumab antitumor efficacy in a mouse tumor model with human cancer cells secreting IdeS, whereas trastuzumab alone showed significantly reduced antitumor activity in the same model. Consistently, an Fc-engineered proteinase-resistant version of trastuzumab also greatly improved antitumor efficacy in the xenograft tumor model. Taken together, these findings point to a novel cancer therapeutic strategy to rescue proteolytic damage of antibody effector function by an Fc-engineered mAb against the hinge neoepitope and to overcome cancer evasion of antibody immunity. Mol Cancer Ther; 14(3); 681–91. ©2014 AACR.
Data from RNA Interference Using c-Myc–Conjugated Nanoparticles Suppresses Breast and Colorectal Cancer Models
Authors: Tangudu Naveen K. , Verma Vinod K. , Clemons Tristan D. , Beevi Syed S. , Hay Trevor , Mahidhara Ganesh , Raja Meera , Nair Rekha A. , Alexander Liza E. , Patel Anant B. , Jose Jedy , Smith Nicole M. , Zdyrko Bogdan , Bourdoncle Anne , Luzinov Igor , Iyer K. Swaminathan , Clarke Alan R. , Dinesh Kumar Lekha
Published: April 2023

Abstract
In this article, we report the development and preclinical validation of combinatorial therapy for treatment of cancers using RNA interference (RNAi). RNAi technology is an attractive approach to silence genes responsible for disease onset and progression. Currently, the critical challenge facing the clinical success of RNAi technology is in the difficulty of delivery of RNAi inducers, due to low transfection efficiency, difficulties of integration into host DNA and unstable expression. Using the macromolecule polyglycidal methacrylate (PGMA) as a platform to graft multiple polyethyleneimine (PEI) chains, we demonstrate effective delivery of small oligos (anti-miRs and mimics) and larger DNAs (encoding shRNAs) in a wide variety of cancer cell lines by successful silencing/activation of their respective target genes. Furthermore, the effectiveness of this therapy was validated for in vivo tumor suppression using two transgenic mouse models; first, tumor growth arrest and increased animal survival was seen in mice bearing Brca2/p53-mutant mammary tumors following daily intratumoral treatment with nanoparticles conjugated to c-Myc shRNA. Second, oral delivery of the conjugate to an Apc-deficient crypt progenitor colon cancer model increased animal survival and returned intestinal tissue to a non–wnt-deregulated state. This study demonstrates, through careful design of nonviral nanoparticles and appropriate selection of therapeutic gene targets, that RNAi technology can be made an affordable and amenable therapy for cancer. Mol Cancer Ther; 14(5); 1259–69. ©2015 AACR.
Data from Validation of the Hsp70–Bag3 Protein–Protein Interaction as a Potential Therapeutic Target in Cancer
Authors: Li Xiaokai , Colvin Teresa , Rauch Jennifer N. , Acosta-Alvear Diego , Kampmann Martin , Dunyak Bryan , Hann Byron , Aftab Blake T. , Murnane Megan , Cho Min , Walter Peter , Weissman Jonathan S. , Sherman Michael Y. , Gestwicki Jason E.
Published: April 2023

Abstract
Hsp70 is a stress-inducible molecular chaperone that is required for cancer development at several steps. Targeting the active site of Hsp70 has proven relatively challenging, driving interest in alternative approaches. Hsp70 collaborates with the Bcl2-associated athanogene 3 (Bag3) to promote cell survival through multiple pathways, including FoxM1. Therefore, inhibitors of the Hsp70–Bag3 protein–protein interaction (PPI) may provide a noncanonical way to target this chaperone. We report that JG-98, an allosteric inhibitor of this PPI, indeed has antiproliferative activity (EC50 values between 0.3 and 4 μmol/L) across cancer cell lines from multiple origins. JG-98 destabilized FoxM1 and relieved suppression of downstream effectors, including p21 and p27. On the basis of these findings, JG-98 was evaluated in mice for pharmacokinetics, tolerability, and activity in two xenograft models. The results suggested that the Hsp70–Bag3 interaction may be a promising, new target for anticancer therapy. Mol Cancer Ther; 14(3); 642–8. ©2015 AACR.
Data from SGN–LIV1A: A Novel Antibody–Drug Conjugate Targeting LIV-1 for the Treatment of Metastatic Breast Cancer
Authors: Sussman Django , Smith Leia M. , Anderson Martha E. , Duniho Steve , Hunter Joshua H. , Kostner Heather , Miyamoto Jamie B. , Nesterova Albina , Westendorf Lori , Van Epps Heather A. , Whiting Nancy , Benjamin Dennis R.
Published: April 2023

Abstract
In this article, we describe a novel antibody–drug conjugate (ADC; SGN–LIV1A), targeting the zinc transporter LIV-1 (SLC39A6) for the treatment of metastatic breast cancer. LIV-1 was previously known to be expressed by estrogen receptor–positive breast cancers. In this study, we show that LIV-1 expression is maintained after hormonal therapy in primary and metastatic sites and is also upregulated in triple-negative breast cancers. In addition to breast cancer, other indications showing LIV-1 expression include melanoma, prostate, ovarian, and uterine cancer. SGN–LIV1A consists of a humanized antibody conjugated through a proteolytically cleavable linker to monomethyl auristatin E, a potent microtubule-disrupting agent. When bound to surface-expressed LIV-1 on immortalized cell lines, this ADC is internalized and traffics to the lysozome. SGN–LIV1A displays specific in vitro cytotoxic activity against LIV-1–expressing cancer cells. In vitro results are recapitulated in vivo where antitumor activity is demonstrated in tumor models of breast and cervical cancer lineages. These results support the clinical evaluation of SGN–LIV1A as a novel therapeutic agent for patients with LIV-1–expressing cancer. Mol Cancer Ther; 13(12); 2991–3000. ©2014 AACR.
Data from Quercetin Targets hnRNPA1 to Overcome Enzalutamide Resistance in Prostate Cancer Cells
Authors: Tummala Ramakumar , Lou Wei , Gao Allen C. , Nadiminty Nagalakshmi
Published: April 2023

Abstract
Prostate cancer remains dependent on androgen receptor signaling even after castration. Aberrant androgen receptor signaling in castration-resistant prostate cancer is mediated by mechanisms such as alterations in the androgen receptor and activation of interacting signaling pathways. Clinical evidence confirms that resistance to the next-generation antiandrogen, enzalutamide, may be mediated to a large extent by alternative splicing of the androgen receptor to generate constitutively active splice variants such as AR-V7. The splice variants AR-V7 and ARv567es have been implicated in the resistance to not only enzalutamide, but also to abiraterone and other conventional therapeutics such as taxanes. Numerous studies, including ours, suggest that splicing factors such as hnRNPA1 promote the generation of AR-V7, thus contributing to enzalutamide resistance in prostate cancer cells. In the present study, we discovered that quercetin, a naturally occurring polyphenolic compound, reduces the expression of hnRNPA1, and consequently, that of AR-V7. The suppression of AR-V7 by quercetin resensitizes enzalutamide-resistant prostate cancer cells to treatment with enzalutamide. Our results indicate that quercetin downregulates hnRNPA1 expression, downregulates the expression of AR-V7, antagonizes androgen receptor signaling, and resensitizes enzalutamide-resistant prostate cancer cells to enzalutamide treatment in vivo in mouse xenografts. These findings demonstrate that suppressing the alternative splicing of the androgen receptor may have important implications in overcoming the resistance to next-generation antiandrogen therapy. Mol Cancer Ther; 16(12); 2770–9. ©2017 AACR.
Data from Synergistic Myeloma Cell Death via Novel Intracellular Activation of Caspase-10–Dependent Apoptosis by Carfilzomib and Selinexor
Authors: Rosebeck Shaun , Alonge Mattina M. , Kandarpa Malathi , Mayampurath Anoop , Volchenboum Samuel L. , Jasielec Jagoda , Dytfeld Dominik , Maxwell Sean P. , Kraftson Stephanie J. , McCauley Dilara , Shacham Sharon , Kauffman Michael , Jakubowiak Andrzej J.
Published: April 2023

Abstract
Exportin1 (XPO1; also known as chromosome maintenance region 1, or CRM1) controls nucleo-cytoplasmic transport of most tumor suppressors and is overexpressed in many cancers, including multiple myeloma, functionally impairing tumor suppressive function via target mislocalization. Selective inhibitor of nuclear export (SINE) compounds block XPO1-mediated nuclear escape by disrupting cargo protein binding, leading to retention of tumor suppressors, induction of cancer cell death, and sensitization to other drugs. Combined treatment with the clinical stage SINE compound selinexor and the irreversible proteasome inhibitor (PI) carfilzomib induced synergistic cell death of myeloma cell lines and primary plasma cells derived from relapsing/refractory myeloma patients and completely impaired the growth of myeloma cell line–derived tumors in mice. Investigating the details of SINE/PI-induced cell death revealed (i) reduced Bcl-2 expression and cleavage and inactivation of Akt, two prosurvival regulators of apoptosis and autophagy; (ii) intracellular membrane-associated aggregation of active caspases, which depended on caspase-10 protease activity; and (iii) novel association of caspase-10 and autophagy-associated proteins p62 and LC3 II, which may prime activation of the caspase cascade. Overall, our findings provide novel mechanistic rationale behind the potent cell death induced by combining selinexor with carfilzomib and support their use in the treatment of relapsed/refractory myeloma and potentially other cancers. Mol Cancer Ther; 15(1); 60–71. ©2015 AACR.
Data from BRAF Mutation Testing in Cell-Free DNA from the Plasma of Patients with Advanced Cancers Using a Rapid, Automated Molecular Diagnostics System
Authors: Janku Filip , Huang Helen J. , Claes Bart , Falchook Gerald S. , Fu Siqing , Hong David , Ramzanali Nishma M. , Nitti Giovanni , Cabrilo Goran , Tsimberidou Apostolia M. , Naing Aung , Piha-Paul Sarina A. , Wheler Jennifer J. , Karp Daniel D. , Holley Veronica R. , Zinner Ralph G. , Subbiah Vivek , Luthra Rajyalakshmi , Kopetz Scott , Overman Michael J. , Kee Bryan K. , Patel Sapna , Devogelaere Benoit , Sablon Erwin , Maertens Geert , Mills Gordon B. , Kurzrock Razelle , Meric-Bernstam Funda
Published: April 2023

Abstract
Cell-free (cf) DNA from plasma offers an easily obtainable material for BRAF mutation analysis for diagnostics and response monitoring. In this study, plasma-derived cfDNA samples from patients with progressing advanced cancers or malignant histiocytosis with known BRAFV600 status from formalin-fixed paraffin-embedded (FFPE) tumors were tested using a prototype version of the Idylla BRAF Mutation Test, a fully integrated real-time PCR-based test with turnaround time about 90 minutes. Of 160 patients, BRAFV600 mutations were detected in 62 (39%) archival FFPE tumor samples and 47 (29%) plasma cfDNA samples. The two methods had overall agreement in 141 patients [88%; κ, 0.74; SE, 0.06; 95% confidence interval (CI), 0.63–0.85]. Idylla had a sensitivity of 73% (95% CI, 0.60–0.83) and specificity of 98% (95% CI, 0.93–1.00). A higher percentage, but not concentration, of BRAFV600 cfDNA in the wild-type background (>2% vs. ≤ 2%) was associated with shorter overall survival (OS; P = 0.005) and in patients with BRAF mutations in the tissue, who were receiving BRAF/MEK inhibitors, shorter time to treatment failure (TTF; P = 0.001). Longitudinal monitoring demonstrated that decreasing levels of BRAFV600 cfDNA were associated with longer TTF (P = 0.045). In conclusion, testing for BRAFV600 mutations in plasma cfDNA using the Idylla BRAF Mutation Test has acceptable concordance with standard testing of tumor tissue. A higher percentage of mutant BRAFV600 in cfDNA corresponded with shorter OS and in patients receiving BRAF/MEK inhibitors also with shorter TTF. Mol Cancer Ther; 15(6); 1397–404. ©2016 AACR.
Data from Inhibition of PI3K/BMX Cell Survival Pathway Sensitizes to BH3 Mimetics in SCLC
Authors: Potter Danielle S. , Galvin Melanie , Brown Stewart , Lallo Alice , Hodgkinson Cassandra L. , Blackhall Fiona , Morrow Christopher J. , Dive Caroline
Published: April 2023

Abstract
Most small cell lung cancer (SCLC) patients are initially responsive to cytotoxic chemotherapy, but almost all undergo fatal relapse with progressive disease, highlighting an urgent need for improved therapies and better patient outcomes in this disease. The proapoptotic BH3 mimetic ABT-737 that targets BCL-2 family proteins demonstrated good single-agent efficacy in preclinical SCLC models. However, so far clinical trials of the BH3 mimetic Navitoclax have been disappointing. We previously demonstrated that inhibition of a PI3K/BMX cell survival signaling pathway sensitized colorectal cancer cells to ABT-737. Here, we show that SCLC cell lines, which express high levels of BMX, become sensitized to ABT-737 upon inhibition of PI3K in vitro, and this is dependent on inhibition of the PI3K-BMX-AKT/mTOR signaling pathway. Consistent with these cell line data, when combined with Navitoclax, PI3K inhibition suppressed tumor growth in both an established SCLC xenograft model and in a newly established circulating tumor cell–derived explant (CDX) model generated from a blood sample obtained at presentation from a chemorefractory SCLC patient. These data show for the first time that a PI3K/BMX signaling pathway plays a role in SCLC cell survival and that a BH3 mimetic plus PI3K inhibition causes prolonged tumor regression in a chemorefractory SCLC patient–derived model in vivo. These data add to a body of evidence that this combination should move toward the clinic. Mol Cancer Ther; 15(6); 1248–60. ©2016 AACR.
Data from Synthesis and Evaluation of the Novel Prostamide, 15-Deoxy, Δ12,14-Prostamide J2, as a Selective Antitumor Therapeutic
Authors: Ladin Daniel A. , Soliman Eman , Escobedo Rene , Fitzgerald Timothy L. , Yang Li V. , Burns Colin , Van Dross Rukiyah
Published: April 2023

Abstract
15-deoxy, Δ12,14-prostaglandin J2-ethanolamide, also known as 15-deoxy, Δ12,14-prostamide J2 (15d-PMJ2) is a novel product of the metabolism of arachidonoyl ethanolamide (AEA) by COX-2. 15d-PMJ2 preferentially induced cell death and apoptosis in tumorigenic A431 keratinocytes and B16F10 melanoma cells compared with nontumorigenic HaCaT keratinocytes and Melan-A melanocytes. Activation of the ER stress execution proteins, PERK and CHOP10, was evaluated to determine whether this process was involved in 15d-PMJ2 cell death. 15d-PMJ2 increased the phosphorylation of PERK and expression of CHOP10 in tumorigenic but not nontumorigenic cells. The known ER stress inhibitors, salubrinal and 4-phenylbutaric acid, significantly inhibited 15d-PMJ2–mediated apoptosis, suggesting ER stress as a primary apoptotic mediator. Furthermore, the reactive double bond present within the cyclopentenone structure of 15d-PMJ2 was identified as a required moiety for the induction of ER stress apoptosis. The effect of 15d-PMJ2 on B16F10 melanoma growth was also evaluated by dosing C57BL/6 mice with 0.5 mg/kg 15d-PMJ2. Tumors of animals treated with 15d-PMJ2 exhibited significantly reduced growth and mean weights compared with vehicle and untreated animals. TUNEL and IHC analysis of tumor tissues showed significant cell death and ER stress in tumors of 15d-PMJ2–treated compared with control group animals. Taken together, these findings suggest that the novel prostamide, 15d-PMJ2, possesses potent antitumor activity in vitro and in vivo. Mol Cancer Ther; 16(5); 838–49. ©2017 AACR.
Data from mTORC1/2 and Protein Translation Regulate Levels of CHK1 and the Sensitivity to CHK1 Inhibitors in Ewing Sarcoma Cells
Authors: Koppenhafer Stacia L. , Goss Kelli L. , Terry William W. , Gordon David J.
Published: April 2023

Abstract
The treatment of Ewing sarcoma has changed very little in the past two decades and novel treatment approaches are needed. We recently identified that Ewing sarcoma cells are uniquely vulnerable to inhibitors of ribonucleotide reductase (RNR), the rate-limiting enzyme in the synthesis of deoxyribonucleotides. We subsequently found that the inhibition of checkpoint kinase 1 (CHK1) increases the sensitivity of Ewing sarcoma cells to inhibitors of RNR, such as gemcitabine. However, Ewing sarcoma cells exhibit high levels of the CHK1 protein, which may represent an adaptive response to elevated levels of endogenous DNA replication stress. Consequently, we began this work with the aim of determining the impact of CHK1 levels on drug sensitivity, as well as identifying the mechanisms and pathways that regulate CHK1 levels in Ewing sarcoma cells. In this report, we show that the high levels of the CHK1 protein in Ewing sarcoma cells limit the efficacy of CHK1 inhibitors. However, inhibition of mTORC1/2 activates the translational repressor 4E-BP1, reduces protein synthesis, and decreases levels of the CHK1 protein in Ewing sarcoma cells. Similarly, we identified that the CHK1 inhibitor prexasertib also activates 4E-BP1, inhibits protein synthesis, and reduces CHK1 protein levels in Ewing sarcoma cells. Moreover, the combination of prexasertib and gemcitabine was synergistic in vitro, caused tumor regression in vivo, and significantly prolonged mouse survival in a Ewing sarcoma xenograft experiment. Overall, our results provide insight into Ewing sarcoma biology and support further investigation of the CHK1 pathway as a therapeutic target in Ewing sarcoma tumors.
Data from Specific RITA Modification Produces Hyperselective Cytotoxicity While Maintaining In Vivo Antitumor Efficacy
Authors: Peyser Brian D. , Hermone Ann , Salamoun Joseph M. , Burnett James C. , Hollingshead Melinda G. , McGrath Connor F. , Gussio Rick , Wipf Peter
Published: April 2023

Abstract
The preclinical antitumor agent RITA (2,5-bis[5-hydroxymethyl-2-thienyl] furan, NSC 652287), an analog of the natural product α-terthiophene, failed during the development phase due to acute pulmonary toxicity in animal models. A series of synthetic modifications to RITA's heterocyclic scaffold resulted in activity ranging from broadly cytotoxic to highly selective. In the NCI 60-cell line screen, these “hyperselective” agents (e.g., imatinib) are rare. A selectivity index (SI) was developed to quantify this desirable feature, which is 20 for imatinib, whereas RITA's SI is only 0.10. One of the described hyperselective RITA analogs (SI = 7.9) completely lost activity in the presence of a known SULT1A1 inhibitor. These results, coupled with previous evidence that RITA is a SULT1A1 substrate, suggest that carbinol modification by a sulfate leaving group and subsequent formation of a reactive carbocation may explain RITA's broad cytotoxicity. Although SULT1A1 expression is required for susceptibility, hyperselective analogs exhibited reduced association of activity with SULT1A1 mRNA expression compared with RITA, apparently requiring some additional target(s). In support of this hypothesis, there is a strong correlation (P < 0.01, r = 0.95) between quantum mechanically calculated energy barriers for carbocation formation from sulfonated analogs and SI, indicating that hyperselective RITA analogs generate reactive carbocations less readily after sulfate activation. Importantly, narrowing the cytotoxicity profile of RITA did not eliminate its analogs' in vivo antitumor activity, as several new hyperselective agents, NSC 773097 (1), 773392 (2), and 782846 (6), displayed impressive activity against A498 xenografts in mice.
Data from Antileukemia Effects of Notch-Mediated Inhibition of Oncogenic PLK1 in B-Cell Acute Lymphoblastic Leukemia
Authors: Kannan Sankaranarayanan , Aitken Marisa J.L. , Herbrich Shelley M. , Golfman Leonard S. , Hall Mandy G. , Mak Duncan H. , Burks Jared K. , Song Guangchun , Konopleva Marina , Mullighan Charles G. , Chandra Joya , Zweidler-McKay Patrick A.
Published: April 2023

Abstract
In B-cell acute lymphoblastic leukemia (B-ALL), activation of Notch signaling leads to cell-cycle arrest and apoptosis. We aimed to harness knowledge acquired by understanding a mechanism of Notch-induced cell death to elucidate a therapeutically viable target in B-ALL. To this end, we identified that Notch activation suppresses Polo-like kinase 1 (PLK1) in a B-ALL–specific manner. We identified that PLK1 is expressed in all subsets of B-ALL and is highest in Philadelphia-like (Ph-like) ALL, a high-risk subtype of disease. We biochemically delineated a mechanism of Notch-induced PLK1 downregulation that elucidated stark regulation of p53 in this setting. Our findings identified a novel posttranslational cascade initiated by Notch in which CHFR was activated via PARP1-mediated PARylation, resulting in ubiquitination and degradation of PLK1. This led to hypophosphorylation of MDM2Ser260, culminating in p53 stabilization and upregulation of BAX. shRNA knockdown or pharmacologic inhibition of PLK1 using BI2536 or BI6727 (volasertib) in B-ALL cell lines and patient samples led to p53 stabilization and cell death. These effects were seen in primary human B-ALL samples in vitro and in patient-derived xenograft models in vivo. These results highlight PLK1 as a viable therapeutic target in B-ALL. Efficacy of clinically relevant PLK1 inhibitors in B-ALL patient-derived xenograft mouse models suggests that use of these agents may be tailored as an additional therapeutic strategy in future clinical studies.
Data from The Role of Pyruvate Dehydrogenase Kinase-4 (PDK4) in Bladder Cancer and Chemoresistance
Authors: Woolbright Benjamin L. , Choudhary Dharamainder , Mikhalyuk Andrew , Trammel Cassandra , Shanmugam Sambantham , Abbott Erika , Pilbeam Carol C. , Taylor John A.
Published: April 2023

Abstract
Advanced bladder cancer remains a major source of mortality, with poor treatment options. Cisplatin-based chemotherapy is the standard treatment, however many patients are or become resistant. One potential cause of chemoresistance is the Warburg effect, a metabolic switch to aerobic glycolysis that occurs in many cancers. Upregulation of the pyruvate dehydrogenase kinase family (PDK1–PDK4) is associated with aerobic glycolysis and chemoresistance through inhibition of the pyruvate dehydrogenase complex (PDH). We have previously observed upregulation of PDK4 in high-grade compared with low-grade bladder cancers. We initiated this study to determine if inhibition of PDK4 could reduce tumor growth rates or sensitize bladder cancer cells to cisplatin. Upregulation of PDK4 in malignant bladder cancer cell lines as compared with benign transformed urothelial cells was confirmed using qPCR. Inhibition of PDK4 with dichloroacetate (DCA) resulted in increased PDH activity, reduced cell growth, and G0–G1 phase arrest in bladder cancer cells. Similarly, siRNA knockdown of PDK4 inhibited bladder cancer cell proliferation. Cotreatment of bladder cancer cells with cisplatin and DCA did not increase caspase-3 activity but did enhance overall cell death in vitro. Although daily treatment with 200 mg/kg DCA alone did not reduce tumor volumes in a xenograft model, combination treatment with cisplatin resulted in dramatically reduced tumor volumes as compared with either DCA or cisplatin alone. This was attributed to substantial intratumoral necrosis. These findings indicate inhibition of PDK4 may potentiate cisplatin-induced cell death and warrant further studies investigating the mechanism through which this occurs. Mol Cancer Ther; 17(9); 2004–12. ©2018 AACR.
Data from c-Jun N-Terminal Kinase Inactivation by Mitogen-Activated Protein Kinase Phosphatase 1 Determines Resistance to Taxanes and Anthracyclines in Breast Cancer
Authors: Rincón Raúl , Zazo Sandra , Chamizo Cristina , Manso Rebeca , González-Alonso Paula , Martín-Aparicio Ester , Cristóbal Ion , Cañadas Carmen , Perona Rosario , Lluch Ana , Eroles Pilar , García-Foncillas Jesús , Albanell Joan , Rovira Ana , Madoz-Gúrpide Juan , Rojo Federico
Published: April 2023

Abstract
MAPK phosphatase-1 (MKP-1) is overexpressed during malignant transformation of the breast in many patients, and it is usually associated with chemoresistance through interference with JNK-driven apoptotic pathways. Although the molecular settings of the mechanism have been documented, details about the contribution of MKP-1 to the failure of chemotherapeutic interventions are unclear. Transient overexpression of MKP-1 and treatment with JNK-modulating agents in breast carcinoma cells confirmed the mediation of MKP-1 in the resistance to taxanes and anthracyclines in breast cancer, through the inactivation of JNK1/2. We next assessed MKP-1 expression and JNK1/2 phosphorylation status in a large cohort of samples from 350 early breast cancer patients treated with adjuvant anthracycline–based chemotherapy. We detected that MKP-1 overexpression is a recurrent event predominantly linked to dephosphorylation of JNK1/2 with an adverse impact on relapse of the tumor and overall and disease-free survival. Moreover, MKP-1 and p-JNK1/2 determinations in 64 locally advanced breast cancer patients treated with neoadjuvant taxane–based chemotherapy showed an inverse correlation between MKP-1 overexpression (together with JNK1/2 inhibition) and the pathologic response of the tumors. Our results emphasize the importance of MKP-1 as a potential predictive biomarker for a subset of breast cancer patients with worse outcome and less susceptibility to treatment. Mol Cancer Ther; 15(11); 2780–90. ©2016 AACR.
Data from Ceramide–Rubusoside Nanomicelles, a Potential Therapeutic Approach to Target Cancers Carrying p53 Missense Mutations
Authors: Khiste Sachin K. , Liu Zhijun , Roy Kartik R. , Uddin Mohammad B. , Hosain Salman B. , Gu Xin , Nazzal Sami , Hill Ronald A. , Liu Yong-Yu
Published: April 2023

Abstract
Ceramide (Cer) is an active cellular sphingolipid that can induce apoptosis or proliferation-arrest of cancer cells. Nanoparticle-based delivery offers an effective approach for overcoming bioavailability and biopharmaceutics issues attributable to the pronounced hydrophobicity of Cer. Missense mutations of the protein p53, which have been detected in approximately 42% of cancer cases, not only lose the tumor suppression activity of wild-type p53, but also gain oncogenic functions promoting tumor progression and drug resistance. Our previous works showed that cellular Cer can eradicate cancer cells that carry a p53 deletion-mutation by modulating alternative pre-mRNA splicing, restoring wild-type p53 protein expression. Here, we report that new ceramide–rubusoside (Cer–RUB) nanomicelles considerably enhance Cer in vivo bioavailability and restore p53-dependent tumor suppression in cancer cells carrying a p53 missense mutation. Natural RUB encapsulated short-chain C6-Cer so as to form Cer–RUB nanomicelles (∼32 nm in diameter) that substantially enhanced Cer solubility and its levels in tissues and tumors of mice dosed intraperitoneally. Intriguingly, Cer–RUB nanomicelle treatments restored p53-dependent tumor suppression and sensitivity to cisplatin in OVCAR-3 ovarian cancer cells and xenograft tumors carrying p53 R248Q mutation. Moreover, Cer–RUB nanomicelles showed no signs of significant nonspecific toxicity to noncancerous cells or normal tissues, including bone marrow. Furthermore, Cer–RUB nanomicelles restored p53 phosphorylated protein and downstream function to wild-type levels in p53 R172H/+ transgenic mice. Altogether, this study, for the first time, indicates that natural Cer–RUB nanomicelles offer a feasible approach for efficaciously and safely targeting cancers carrying p53 missense mutations.
Data from Rational Combination Therapy for Melanoma with Dinaciclib by Targeting BAK-Dependent Cell Death
Authors: Xu Xiaoou , Eshima Shizuka , Kato Shinichiro , Fisher David E. , Sakurai Hiroaki , Hayakawa Yoshihiro , Yokoyama Satoru
Published: April 2023

Abstract
Mutation of the oncogene BRAF is among the most common genetic alterations in melanoma. BRAF inhibitors alone or in combination with MEK inhibitors fail to eradicate the tumor in most patients due to combinations of intrinsic or acquired resistance. Therefore, novel strategies are needed to improve the therapeutic efficacy of BRAF inhibition. We demonstrated that dinaciclib has potent antimelanoma effects by inducing BAK-dependent apoptosis through MCL1 reduction. Contrary to dinaciclib, the inhibitors of BRAF/MEK/CDK4/6 induced apoptosis dominantly through a BAX-dependent mechanism. Although the combination of BRAF and MEK inhibitors did not exhibit additive antimelanoma effects, their combination with dinaciclib synergistically inhibited melanoma growth both in vitro and in vivo. Collectively, our present findings suggest dinaciclib to be an effective complementary drug of BAX-dependent antimelanoma drugs by targeting BAK-mediated apoptosis, and other such rational drug combinations can be determined by identifying complementary drugs activating either BAK or BAX.