bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from PET Imaging of β-Glucuronidase Activity by an Activity-Based 124I-Trapping Probe for the Personalized Glucuronide Prodrug Targeted Therapy
Authors: Su Yu-Cheng , Cheng Ta-Chun , Leu Yu-Ling , Roffler Steve R. , Wang Jaw-Yuan , Chuang Chih-Hung , Kao Chien-Han , Chen Kai-Chuan , Wang Hsin-Ell , Cheng Tian-Lu
Published: March 2024

Abstract
Beta-glucuronidase (βG) is a potential biomarker for cancer diagnosis and prodrug therapy. The ability to image βG activity in patients would assist in personalized glucuronide prodrug cancer therapy. However, whole-body imaging of βG activity for medical usage is not yet available. Here, we developed a radioactive βG activity–based trapping probe for positron emission tomography (PET). We generated a 124I-tyramine–conjugated difluoromethylphenol beta-glucuronide probe (TrapG) to form 124I-TrapG that could be selectively activated by βG for subsequent attachment of 124I-tyramine to nucleophilic moieties near βG-expressing sites. We estimated the specificity of a fluorescent FITC-TrapG, the cytotoxicity of tyramine-TrapG, and the serum half-life of 124I-TrapG. βG targeting of 124I-TrapG in vivo was examined by micro-PET. The biodistribution of 131I-TrapG was investigated in different organs. Finally, we imaged the endogenous βG activity and assessed its correlation with therapeutic efficacy of 9-aminocamptothecin glucuronide (9ACG) prodrug in native tumors. FITC-TrapG showed specific trapping at βG-expressing CT26 (CT26/mβG) cells but not in CT26 cells. The native TrapG probe possessed low cytotoxicity. 124I-TrapG preferentially accumulated in CT26/mβG but not CT26 cells. Meanwhile, micro-PET and whole-body autoradiography results demonstrated that 124I-TrapG signals in CT26/mβG tumors were 141.4-fold greater than in CT26 tumors. Importantly, Colo205 xenografts in nude mice that express elevated endogenous βG can be monitored by using infrared glucuronide trapping probes (NIR-TrapG) and suppressed by 9ACG prodrug treatment. 124I-TrapG exhibited low cytotoxicity allowing long-term monitoring of βG activity in vivo to aid in the optimization of prodrug targeted therapy. Mol Cancer Ther; 13(12); 2852–63. ©2014 AACR.
Data from Evasion Mechanisms to Igf1r Inhibition in Rhabdomyosarcoma
Authors: Abraham Jinu , Prajapati Suresh I. , Nishijo Koichi , Schaffer Beverly S. , Taniguchi Eri , Kilcoyne Aoife , McCleish Amanda T. , Nelon Laura D. , Giles Francis G. , Efstratiadis Argiris , LeGallo Robin D. , Nowak Brent M. , Rubin Brian P. , Malempati Suman , Keller Charles
Published: March 2024

Abstract
Inhibition of the insulin-like growth factor 1 receptor (Igf1r) is an approach being taken in clinical trials to overcome the dismal outcome for metastatic alveolar rhabdomyosarcoma (ARMS), an aggressive muscle cancer of children and young adults. In our study, we address the potential mechanism(s) of Igf1r inhibitor resistance that might be anticipated for patients. Using a genetically engineered mouse model of ARMS, validated for active Igf1r signaling, we show that the prototypic Igf1r inhibitor NVP-AEW541 can inhibit cell growth and induce apoptosis in vitro in association with decreased Akt and Mapk phosphorylation. However, drug resistance in vivo is more common and is accompanied by Igf1r overexpression, Mapk reactivation, and Her2 overexpression. Her2 is found to form heterodimers with Igf1r in resistant primary tumor cell cultures, and stimulation with Igf2 leads to Her2 phosphorylation. The Her2 inhibitor lapatinib cooperates with NVP-AEW541 to reduce Igf1r phosphorylation and to inhibit cell growth even though lapatinib alone has little effect on growth. These results point to the potential therapeutic importance of simultaneous targeting of Igf1r and Her2 to abrogate resistance. Mol Cancer Ther; 10(4); 697–707. ©2011 AACR.
Data from LY2606368 Causes Replication Catastrophe and Antitumor Effects through CHK1-Dependent Mechanisms
Authors: King Constance , Diaz H. Bruce , McNeely Samuel , Barnard Darlene , Dempsey Jack , Blosser Wayne , Beckmann Richard , Barda David , Marshall Mark S.
Published: March 2024

Abstract
CHK1 is a multifunctional protein kinase integral to both the cellular response to DNA damage and control of the number of active replication forks. CHK1 inhibitors are currently under investigation as chemopotentiating agents due to CHK1's role in establishing DNA damage checkpoints in the cell cycle. Here, we describe the characterization of a novel CHK1 inhibitor, LY2606368, which as a single agent causes double-stranded DNA breakage while simultaneously removing the protection of the DNA damage checkpoints. The action of LY2606368 is dependent upon inhibition of CHK1 and the corresponding increase in CDC25A activation of CDK2, which increases the number of replication forks while reducing their stability. Treatment of cells with LY2606368 results in the rapid appearance of TUNEL and pH2AX-positive double-stranded DNA breaks in the S-phase cell population. Loss of the CHK1-dependent DNA damage checkpoints permits cells with damaged DNA to proceed into early mitosis and die. The majority of treated mitotic nuclei consist of extensively fragmented chromosomes. Inhibition of apoptosis by the caspase inhibitor Z-VAD-FMK had no effect on chromosome fragmentation, indicating that LY2606368 causes replication catastrophe. Changes in the ratio of RPA2 to phosphorylated H2AX following LY2606368 treatment further support replication catastrophe as the mechanism of DNA damage. LY2606368 shows similar activity in xenograft tumor models, which results in significant tumor growth inhibition. LY2606368 is a potent representative of a novel class of drugs for the treatment of cancer that acts through replication catastrophe. Mol Cancer Ther; 14(9); 2004–13. ©2015 AACR.
Data from Nanolipolee-007, a Novel Nanoparticle-Based Drug Containing Leelamine for the Treatment of Melanoma
Authors: Gowda Raghavendra , Madhunapantula SubbaRao V. , Sharma Arati , Kuzu Omer F. , Robertson Gavin P.
Published: March 2024

Abstract
Malignant melanoma is a difficult cancer to treat due to the rapid development of resistance to drugs targeting single proteins. One response to this observation is to identify single pharmacologic agents that, due to a unique mechanism of action, simultaneously target multiple key pathways involved in melanoma development. Leelamine has been identified as functioning in this manner but has poor bioavailability in animals and causes lethality when administered intravenously. Therefore, a nanoliposomal-based delivery system has been developed, called Nanolipolee-007, which stably loads 60% of the compound. The nanoparticle was as effective at killing melanoma cells as leelamine dissolved in DMSO and was more effective at killing cultured melanoma compared with normal cells. Mechanistically, Nanolipolee-007 inhibited PI3K/Akt, STAT3, and MAPK signaling mediated through inhibition of cholesterol transport. Nanolipolee-007 inhibited the growth of preexisting xenografted melanoma tumors by an average of 64% by decreasing cellular proliferation, reducing tumor vascularization, and increasing cellular apoptosis, with negligible toxicity. Thus, a unique clinically viable nanoparticle-based drug has been developed containing leelamine for the treatment of melanoma that acts by inhibiting the activity of major signaling pathways regulating the development of this disease. Mol Cancer Ther; 13(10); 2328–40. ©2014 AACR.
Data from Preclinical Test of Dacomitinib, an Irreversible EGFR Inhibitor, Confirms Its Effectiveness for Glioblastoma
Authors: Zahonero Cristina , Aguilera Pilar , Ramírez-Castillejo Carmen , Pajares Marta , Bolós Maria Victoria , Cantero Diana , Perez-Nuñez Angel , Hernández-Laín Aurelio , Sánchez-Gómez Pilar , Sepúlveda Juan Manuel
Published: March 2024

Abstract
Glioblastomas (GBM) are devastating tumors in which there has been little clinical improvement in the last decades. New molecularly directed therapies are under development. EGFR is one of the most promising targets, as this receptor is mutated and/or overexpressed in nearly half of the GBMs. However, the results obtained with first-generation tyrosine-kinase inhibitors have been disappointing with no clear predictive markers of tumor response. Here, we have tested the antitumoral efficacy of a second-generation inhibitor, dacomitinib (PF299804, Pfizer), that binds in an irreversible way to the receptor. Our results confirm that dacomitinib has an effect on cell viability, self-renewal, and proliferation in EGFR-amplified ± EGFRvIII GBM cells. Moreover, systemic administration of dacomitinib strongly impaired the in vivo tumor growth rate of these EGFR-amplified cell lines, with a decrease in the expression of stem cell–related markers. However, continuous administration of the compound was required to maintain the antitumor effect. The data presented here confirm that dacomitinib clearly affects receptor signaling in vivo and that its strong antitumoral effect is independent of the presence of mutant receptor isoforms although it could be affected by the PTEN status (as it is less effective in a PTEN-deleted GBM line). Dacomitinib is being tested in second line for EGFR-amplified GBMs. We hope that our results could help to select retrospectively molecular determinants of this response and to implement future trials with dacomitinib (alone or in combination with other inhibitors) in newly diagnosed GBMs. Mol Cancer Ther; 14(7); 1548–58. ©2015 AACR.
Data from Targeting FGFR Pathway in Human Hepatocellular Carcinoma: Expressing pFGFR and pMET for Antitumor Activity
Authors: Jo Jae-Cheol , Choi Eun Kyoung , Shin Jae-Sik , Moon Jai-Hee , Hong Seung-Woo , Lee Ha-Reum , Kim Seung-Mi , Jung Soo-A , Lee Dae-Hee , Jung Seang Hwan , Lee Sun-Hye , Kim Jeong Eun , Kim Kyu-pyo , Hong Yong Sang , Suh Young-Ah , Jang Se Jin , Choi Eun Kyung , Lee Jung Shin , Jin Dong-Hoon , Kim Tae Won
Published: March 2024

Abstract
The MET receptor tyrosine kinase, the receptor for hepatocyte growth factor (HGF), has been implicated in cancer growth, invasion, migration, angiogenesis, and metastasis in a broad variety of human cancers, including human hepatocellular carcinoma (HCC). Recently, MET was suggested to be a potential target for the personalized treatment of HCC with an active HGF–MET signaling pathway. However, the mechanisms of resistance to MET inhibitors need to be elucidated to provide effective treatment. Here, we show that HCC cells exhibit different sensitivities to the MET inhibitor PHA665752, depending on the phosphorylation status of FGFR. Treatment of cells expressing both phospho-FGFR and phospho-MET with the inhibitor PHA665752 did not cause growth inhibition and cell death, whereas treatment with AZD4547, a pan-FGFR inhibitor, resulted in decreased colony formation and cleavage of caspase-3. Moreover, silencing of endogenous FGFR1 and FGFR2 by RNAi of HCC cells expressing phospho-FGFR, phospho-FGFR2, and phospho-MET overcame the resistance to PHA665752 treatment. Treatment of primary cancer cells from patients with HCC expressing both phospho-FGFR and phospho-MET with PHA665752 did not induce cell death, whereas AZD4547 treatment induced cell death through the cleavage of caspase-3. In addition, treatment of cells resistant to PHA665752 with AZD4547 abrogated the activation of downstream effectors of cell growth, proliferation, and survival. On the basis of these results, we conclude that the FGFR pathway is critical for HCC survival, and that targeting this pathway with AZD4547 may be beneficial for the treatment of patients with HCC-expressing phospho-FGFR and phospho-MET. Mol Cancer Ther; 14(11); 2613–22. ©2015 AACR.
Data from Radiosensitization of Primary Human Glioblastoma Stem-like Cells with Low-Dose AKT Inhibition
Authors: Mehta Monal , Khan Atif , Danish Shabbar , Haffty Bruce G. , Sabaawy Hatem E.
Published: March 2024

Abstract
Glioblastoma (GBM) is the most frequent and lethal brain cancer. The lack of early detection methods, the presence of rapidly growing tumor cells, and the high levels of recurrence due to chemo- and radioresistance make this cancer an extremely difficult disease to treat. Emerging studies have focused on inhibiting AKT activation; here, we demonstrate that in primary GBM tumor samples, full-dose inhibition of AKT activity leads to differential responses among samples in the context of cell death and self-renewal, reinforcing the notion that GBM is a heterogeneous disease. In contrast, low-dose AKT inhibition when combined with fractionation of radiation doses leads to a significant apoptosis-mediated cell death of primary patient–derived GBM cells. Therefore, low-dose–targeted therapies might be better for radiosensitization of primary GBM cells and further allow for reducing the clinical toxicities often associated with targeting the AKT/PI3K/mTOR pathway. This work emphasizes the discrepancies between cell lines and primary tumors in drug testing, and indicates that there are salient differences between patients, highlighting the need for personalized medicine in treating high-grade glioma. Mol Cancer Ther; 14(5); 1171–80. ©2015 AACR.
Data from Syngeneic Murine Ovarian Cancer Model Reveals That Ascites Enriches for Ovarian Cancer Stem-Like Cells Expressing Membrane GRP78
Authors: Mo Lihong , Bachelder Robin E. , Kennedy Margaret , Chen Po-Han , Chi Jen-Tsan , Berchuck Andrew , Cianciolo George , Pizzo Salvatore V.
Published: March 2024

Abstract
Patients with ovarian cancer are generally diagnosed at FIGO (International Federation of Gynecology and Obstetrics) stage III/IV, when ascites is common. The volume of ascites correlates positively with the extent of metastasis and negatively with prognosis. Membrane GRP78, a stress-inducible endoplasmic reticulum chaperone that is also expressed on the plasma membrane (memGRP78) of aggressive cancer cells, plays a crucial role in the embryonic stem cell maintenance. We studied the effects of ascites on ovarian cancer stem-like cells using a syngeneic mouse model. Our study demonstrates that ascites-derived tumor cells from mice injected intraperitoneally with murine ovarian cancer cells (ID8) express increased memGRP78 levels compared with ID8 cells from normal culture. We hypothesized that these ascites-associated memGRP78+ cells are cancer stem-like cells (CSC). Supporting this hypothesis, we show that memGRP78+ cells isolated from murine ascites exhibit increased sphere forming and tumor initiating abilities compared with memGRP78− cells. When the tumor microenvironment is recapitulated by adding ascites fluid to cell culture, ID8 cells express more memGRP78 and increased self-renewing ability compared with those cultured in medium alone. Moreover, compared with their counterparts cultured in normal medium, ID8 cells cultured in ascites, or isolated from ascites, show increased stem cell marker expression. Antibodies directed against the carboxy-terminal domain of GRP78: (i) reduce self-renewing ability of murine and human ovarian cancer cells preincubated with ascites and (ii) suppress a GSK3α-AKT/SNAI1 signaling axis in these cells. Based on these data, we suggest that memGRP78 is a logical therapeutic target for late-stage ovarian cancer. Mol Cancer Ther; 14(3); 747–56. ©2015 AACR.
Data from Mechanisms of Resistance to Cabazitaxel
Authors: Duran George E. , Wang Yan C. , Francisco E. Brian , Rose John C. , Martinez Francisco J. , Coller John , Brassard Diana , Vrignaud Patricia , Sikic Branimir I.
Published: March 2024

Abstract
We studied mechanisms of resistance to the novel taxane cabazitaxel in established cellular models of taxane resistance. We also developed cabazitaxel-resistant variants from MCF-7 breast cancer cells by stepwise selection in drug alone (MCF-7/CTAX) or drug plus the transport inhibitor PSC-833 (MCF-7/CTAX-P). Among multidrug-resistant (MDR) variants, cabazitaxel was relatively less cross-resistant than paclitaxel and docetaxel (15- vs. 200-fold in MES-SA/Dx5 and 9- vs. 60-fold in MCF-7/TxT50, respectively). MCF-7/TxTP50 cells that were negative for MDR but had 9-fold resistance to paclitaxel were also 9-fold resistant to cabazitaxel. Selection with cabazitaxel alone (MCF-7/CTAX) yielded 33-fold resistance to cabazitaxel, 52-fold resistance to paclitaxel, activation of ABCB1, and 3-fold residual resistance to cabazitaxel with MDR inhibition. The MCF-7/CTAX-P variant did not express ABCB1, nor did it efflux rhodamine-123, BODIPY-labeled paclitaxel, and [3H]-docetaxel. These cells are hypersensitive to depolymerizing agents (vinca alkaloids and colchicine), have reduced baseline levels of stabilized microtubules, and impaired tubulin polymerization in response to taxanes (cabazitaxel or docetaxel) relative to MCF-7 parental cells. Class III β-tubulin (TUBB3) RNA and protein were elevated in both MCF-7/CTAX and MCF-7/CTAX-P. Decreased BRCA1 and altered epithelial–mesenchymal transition (EMT) markers are also associated with cabazitaxel resistance in these MCF-7 variants, and may serve as predictive biomarkers for its activity in the clinical setting. In summary, cabazitaxel resistance mechanisms include MDR (although at a lower level than paclitaxel and docetaxel), and alterations in microtubule dynamicity, as manifested by higher expression of TUBB3, decreased BRCA1, and by the induction of EMT. Mol Cancer Ther; 14(1); 193–201. ©2014 AACR.
Data from The Tyrphostin NT157 Suppresses Insulin Receptor Substrates and Augments Therapeutic Response of Prostate Cancer
Authors: Ibuki Naokazu , Ghaffari Mazyar , Reuveni Hadas , Pandey Mitali , Fazli Ladan , Azuma Haruhito , Gleave Martin E. , Levitzki Alexander , Cox Michael E.
Published: March 2024

Abstract
Insulin-like growth factor (IGF) signaling is associated with castrate-resistant prostate cancer (CRPC) progression. Insulin receptor substrates 1 and 2 (IRS1/2) mediate mitogenic and antiapoptotic signaling from IGF1 receptor (IGF1R), insulin receptor, and other oncoproteins. This study demonstrates that IRS1/2 expression is increased in prostate cancer, and persists in CRPC. Furthermore, this study assesses the anticancer activity of NT157, a small molecule tyrphostin targeting IRS proteins, using androgen-responsive (LNCaP) and -independent (PC3) prostate cancer cells in vitro and in vivo. NT157 treatment resulted in dose-dependent inhibition of IGF1R activation, suppression of IRS protein expression, inhibition of IGF1-induced AKT activation, but increased ERK activation in NT157-treated cells in vitro. These effects were correlated with decreased proliferation and increasing apoptosis of LNCaP cells and increasing G2–M arrest in PC3 cells. NT157 also suppressed androgen-responsive growth, delayed CRPC progression of LNCaP xenografts, and suppressed PC3 tumor growth alone and in combination with docetaxel. This study reports the first preclinical proof-of-principle data that this novel small molecule tyrosine kinase inhibitor suppresses IRS1/2 expression, delays CRPC progression, and suppresses growth of CRPC tumors in vitro and in vivo. Demonstration that IRS expression can be increased in response to a variety of stressors that may lead to resistance or reduced effect of the therapies indicate that NT157-mediated IRS1/2 downregulation is a novel therapeutic approach for management of advanced prostate cancer. Mol Cancer Ther; 13(12); 2827–39. ©2014 AACR.
Data from GPR54 Is a Target for Suppression of Metastasis in Endometrial Cancer
Authors: Kang Hyun Sook , Baba Tsukasa , Mandai Masaki , Matsumura Noriomi , Hamanishi Junzo , Kharma Budiman , Kondoh Eiji , Yoshioka Yumiko , Oishi Shinya , Fujii Nobutaka , Murphy Susan K. , Konishi Ikuo
Published: March 2024

Abstract
Invasion into deep myometrium and/or lymphovascular space is a well-known risk factor for endometrial cancer metastasis, resulting in poor prognosis. It is therefore clinically important to identify novel molecules that suppress tumor invasion. Reduced expression of the metastasis suppressor, kisspeptin (KISS1), and its endogenous receptor, GPR54, has been reported in several cancers, but the significance of the KISS1/GPR54 axis in endometrial cancer metastasis has not been clarified. Metastin-10 is the minimal bioactive sequence of genetic products of KISS1. Clinicopathological analysis of 92 endometrial cancers revealed overall survival is improved in cancers with high expression of GPR54 (P < 0.05) and that GPR54 expression is associated with known prognostic factors including FIGO stage, grade, and deep myometrial invasion. Through RNAi and microarray analyses, metastin-10 was predicted to suppress metastasis of GPR54-expressing endometrial cancers in vivo. Methylation analysis revealed GPR54 is epigenetically regulated. Metastin-GPR54 axis function was restored following treatment with the DNA hypomethylating agent 5-aza-DC. These data suggest that metastin-10 may be effective at inhibiting the metastatic spread of endometrial cancers in combination with demethylating agents to induce GPR54 expression. Mol Cancer Ther; 10(4); 580–90. ©2011 AACR.
Data from RacGAP1 Is a Novel Downstream Effector of E2F7-Dependent Resistance to Doxorubicin and Is Prognostic for Overall Survival in Squamous Cell Carcinoma
Authors: Hazar-Rethinam Mehlika , de Long Lilia Merida , Gannon Orla M. , Boros Samuel , Vargas Ana Cristina , Dzienis Marcin , Mukhopadhyay Pamela , Saenz-Ponce Natalia , Dantzic Daniel D.E. , Simpson Fiona , Saunders Nicholas A.
Published: March 2024

Abstract
We have previously shown that E2F7 contributes to drug resistance in head and neck squamous cell carcinoma (HNSCC) cells. Considering that dysregulation of responses to chemotherapy-induced cytotoxicity is one of the major reasons for treatment failure in HNSCC, identifying the downstream effectors that regulate E2F7-dependent sensitivity to chemotherapeutic agents may have direct clinical impact. We used transcriptomic profiling to identify candidate pathways that contribute to E2F7-dependent resistance to doxorubicin. We then manipulated the expression of the candidate pathway using overexpression and knockdown in in vitro and in vivo models of SCC to demonstrate causality. In addition, we examined the expression of E2F7 and RacGAP1 in a custom tissue microarray (TMA) generated from HNSCC patient samples. Transcriptomic profiling identified RacGAP1 as a potential mediator of E2F7-dependent drug resistance. We validated E2F7-dependent upregulation of RacGAP1 in doxorubicin-insensitive SCC25 cells. Extending this, we found that selective upregulation of RacGAP1 induced doxorubicin resistance in previously sensitive KJDSV40. Similarly, stable knockdown of RacGAP1 in insensitive SCC25 cells induced sensitivity to doxorubicin in vitro and in vivo. RacGAP1 expression was validated in a TMA, and we showed that HNSCCs that overexpress RacGAP1 are associated with a poorer patient overall survival. Furthermore, E2F7-induced doxorubicin resistance was mediated via RacGAP1-dependent activation of AKT. Finally, we show that SCC cells deficient in RacGAP1 grow slower and are sensitized to the cytotoxic actions of doxorubicin in vivo. These findings identify RacGAP1 overexpression as a novel prognostic marker of survival and a potential target to sensitize SCC to doxorubicin. Mol Cancer Ther; 14(8); 1939–50. ©2015 AACR.
Data from The TMPRSS2–ERG Gene Fusion Blocks XRCC4-Mediated Nonhomologous End-Joining Repair and Radiosensitizes Prostate Cancer Cells to PARP Inhibition
Authors: Chatterjee Payel , Choudhary Gaurav S. , Alswillah Turkeyah , Xiong Xiahui , Heston Warren D. , Magi-Galluzzi Cristina , Zhang Junran , Klein Eric A. , Almasan Alexandru
Published: March 2024

Abstract
Exposure to genotoxic agents, such as ionizing radiation (IR), produces DNA damage, leading to DNA double-strand breaks (DSB); IR toxicity is augmented when the DNA repair is impaired. We reported that radiosensitization by a PARP inhibitor (PARPi) was highly prominent in prostate cancer cells expressing the TMPRSS2–ERG gene fusion protein. Here, we show that TMPRSS2–ERG blocks nonhomologous end-joining (NHEJ) DNA repair by inhibiting DNA-PKcs. VCaP cells, which harbor TMPRSS2–ERG and PC3 cells that stably express it, displayed γH2AX and 53BP1 foci constitutively, indicating persistent DNA damage that was absent if TMPRSS2–ERG was depleted by siRNA in VCaP cells. The extent of DNA damage was enhanced and associated with TMPRSS2–ERG's ability to inhibit DNA-PKcs function, as indicated by its own phosphorylation (Thr2609, Ser2056) and that of its substrate, Ser1778-53BP1. DNA-PKcs deficiency caused by TMPRSS2–ERG destabilized critical NHEJ components on chromatin. Thus, XRCC4 was not recruited to chromatin, with retention of other NHEJ core factors being reduced. DNA-PKcs autophosphorylation was restored to the level of parental cells when TMPRSS2–ERG was depleted by siRNA. Following IR, TMPRSS2–ERG-expressing PC3 cells had elevated Rad51 foci and homologous recombination (HR) activity, indicating that HR compensated for defective NHEJ in these cells, hence addressing why TMPRSS2–ERG alone did not lead to radiosensitization. However, the presence of TMPRSS2–ERG, by inhibiting NHEJ DNA repair, enhanced PARPi-mediated radiosensitization. IR in combination with PARPi resulted in enhanced DNA damage in TMPRSS2–ERG-expressing cells. Therefore, by inhibiting NHEJ, TMPRSS2–ERG provides a synthetic lethal interaction with PARPi in prostate cancer patients expressing TMPRSS2–ERG. Mol Cancer Ther; 14(8); 1896–906. ©2015 AACR.
Data from Pharmacogenetic Predictors of Outcome in Patients with Stage II and III Colon Cancer Treated with Oxaliplatin and Fluoropyrimidine-Based Adjuvant Chemotherapy
Authors: Custodio Ana , Moreno-Rubio Juan , Aparicio Jorge , Gallego-Plazas Javier , Yaya Ricardo , Maurel Joan , Rodríguez-Salas Nuria , Burgos Emilio , Ramos David , Calatrava Ana , Andrada Encarna , Díaz-López Esther , Sánchez Antonio , Madero Rosario , Cejas Paloma , Feliu Jaime
Published: March 2024

Abstract
Identifying molecular markers for tumor recurrence is critical in successfully selecting patients with colon cancer who are more likely to benefit from adjuvant chemotherapy. We investigated the effect of single-nucleotide polymorphisms (SNP) within genes involved in oxaliplatin and fluoropyrimidines metabolism, DNA repair mechanisms, drug transport, or angiogenesis pathways on outcome for patients with stage II and III colon cancer treated with adjuvant chemotherapy. Genomic DNA was extracted from formalin-fixed paraffin-embedded samples of 202 patients with stage II and III colon cancer receiving oxaliplatin-based adjuvant chemotherapy from January 2004 to December 2009. Genotyping was performed for 67 SNPs in 32 genes using the MassARRAY (SEQUENOM) technology. Our results were validated in an independent cohort of 177 patients treated with the same chemotherapy regimens. The combination of the selectin E (SELE) rs3917412 G>A G/G and the methylentetrahydrofolate reductase (MTHFR) rs1801133 T/T genotypes was associated with a significantly increased risk for recurrence in both the training [RR = 4.103; 95% confidence interval (CI), 1.803–9.334; P = 0.001] and the validation cohorts (RR = 3.567; 95% CI, 1.253–10.151; P = 0.017) in the multiple regression analysis considering the stage, lymphovascular invasion, and bowel perforation as covariates. The combined analysis of these polymorphisms was also significantly associated with overall survival in both cohorts (RR = 3.388; 95% CI, 0.988–11.623; P = 0.052, and RR = 3.929; 95% CI, 1.144–13.485; P = 0.020, respectively). Our findings suggest that the SELE rs3917412 and MTHFR rs1801133 SNPs could serve as pharmacogenetic predictors of tumor recurrence in patients with early-stage colon cancer treated with oxaliplatin-based adjuvant chemotherapy, thus allowing personalized selection of treatment to optimize clinical outcomes. Mol Cancer Ther; 13(9); 2226–37. ©2014 AACR.
Data from NF-κB2/p52:c-Myc:hnRNPA1 Pathway Regulates Expression of Androgen Receptor Splice Variants and Enzalutamide Sensitivity in Prostate Cancer
Authors: Nadiminty Nagalakshmi , Tummala Ramakumar , Liu Chengfei , Lou Wei , Evans Christopher P. , Gao Allen C.
Published: March 2024

Abstract
Castration-resistant prostate cancer (CRPC) remains dependent on androgen receptor (AR) signaling. Alternative splicing of the AR to generate constitutively active, ligand-independent variants is one of the principal mechanisms that promote the development of resistance to next-generation antiandrogens such as enzalutamide. Here, we demonstrate that the splicing factor heterogeneous nuclear RNA-binding protein A1 (hnRNPA1) plays a pivotal role in the generation of AR splice variants such as AR-V7. hnRNPA1 is overexpressed in prostate tumors compared with benign prostates, and its expression is regulated by NF-κB2/p52 and c-Myc. CRPC cells resistant to enzalutamide exhibit higher levels of NF-κB2/p52, c-Myc, hnRNPA1, and AR-V7. Levels of hnRNPA1 and AR-V7 are positively correlated with each other in prostate cancer. The regulatory circuit involving NF-κB2/p52, c-Myc, and hnRNPA1 plays a central role in the generation of AR splice variants. Downregulation of hnRNPA1 and consequently of AR-V7 resensitizes enzalutamide-resistant cells to enzalutamide, indicating that enhanced expression of hnRNPA1 may confer resistance to AR-targeted therapies by promoting the generation of splice variants. These findings may provide a rationale for cotargeting these pathways to achieve better efficacy through AR blockade. Mol Cancer Ther; 14(8); 1884–95. ©2015 AACR.
Data from Alectinib Shows Potent Antitumor Activity against RET-Rearranged Non–Small Cell Lung Cancer
Authors: Kodama Tatsushi , Tsukaguchi Toshiyuki , Satoh Yasuko , Yoshida Miyuki , Watanabe Yoshiaki , Kondoh Osamu , Sakamoto Hiroshi
Published: March 2024

Abstract
Alectinib/CH5424802 is a known inhibitor of anaplastic lymphoma kinase (ALK) and is being evaluated in clinical trials for the treatment of ALK fusion–positive non–small cell lung cancer (NSCLC). Recently, some RET and ROS1 fusion genes have been implicated as driver oncogenes in NSCLC and have become molecular targets for antitumor agents. This study aims to explore additional target indications of alectinib by testing its ability to inhibit the activity of kinases other than ALK. We newly verified that alectinib inhibited RET kinase activity and the growth of RET fusion–positive cells by suppressing RET phosphorylation. In contrast, alectinib hardly inhibited ROS1 kinase activity unlike other ALK/ROS1 inhibitors such as crizotinib and LDK378. It also showed antitumor activity in mouse models of tumors driven by the RET fusion. In addition, alectinib showed kinase inhibitory activity against RET gatekeeper mutations (RET V804L and V804M) and blocked cell growth driven by the KIF5B-RET V804L and V804M. Our results suggest that alectinib is effective against RET fusion–positive tumors. Thus, alectinib might be a therapeutic option for patients with RET fusion–positive NSCLC. Mol Cancer Ther; 13(12); 2910–8. ©2014 AACR.
Data from Heregulin–ErbB3-Driven Tumor Growth Persists in PI3 Kinase Mutant Cancer Cells
Authors: Yarar Defne , Lahdenranta Johanna , Kubasek William , Nielsen Ulrik B. , MacBeath Gavin
Published: March 2024

Abstract
PI3K is frequently mutated in cancer and plays an important role in cell growth and survival. Heregulin (HRG)-mediated autocrine or paracrine signaling through the receptor tyrosine kinase ErbB3 potently activates the PI3K/AKT pathway and has been shown to mediate resistance to a wide variety of anticancer agents. Although PI3K functions downstream of HRG–ErbB3, it is unknown whether activating mutations in PI3K render HRG ineffective. If so, patients with PI3K mutations would not be expected to benefit from ErbB3-directed therapies. Here, we find that a subset of cell lines harboring activating PI3K mutations can be further growth-stimulated by HRG, and this effect is blocked by incubation with seribantumab (MM-121), a monoclonal anti-ErbB3 antibody. Although expression of mutant PI3K in wild-type PI3K cells frequently results in loss of HRG-stimulated growth, some cell lines continue to respond to HRG. In cell lines where HRG-stimulated growth is lost, this loss is invariably accompanied by a reduction in ErbB3 levels, a corresponding increase in basal phosphorylation levels of FOXO-family transcription factors, and a reduction in HRG-induced downstream signaling. Importantly, HRG-stimulated growth is partially rescued by re-expressing ErbB3. This response is blocked by seribantumab, indicating that ErbB3 levels rather than downstream signaling proteins limit HRG-stimulated growth in PI3K mutant cells. Overall, these results suggest that activating mutations in PI3K do not preclude potential benefit from ErbB3-directed therapy, but that it may be important to measure ErbB3 levels in patients with PI3K mutant cancers to determine if they would benefit. Mol Cancer Ther; 14(9); 2072–80. ©2015 AACR.
Data from Lipid Catabolism via CPT1 as a Therapeutic Target for Prostate Cancer
Authors: Schlaepfer Isabel R. , Rider Leah , Rodrigues Lindsey Ulkus , Gijón Miguel A. , Pac Colton T. , Romero Lina , Cimic Adela , Sirintrapun S. Joseph , Glodé L. Michael , Eckel Robert H. , Cramer Scott D.
Published: March 2024

Abstract
Prostate cancer is the most commonly diagnosed malignancy among Western men and accounts for the second leading cause of cancer-related deaths. Prostate cancer tends to grow slowly and recent studies suggest that it relies on lipid fuel more than on aerobic glycolysis. However, the biochemical mechanisms governing the relationships between lipid synthesis, lipid utilization, and cancer growth remain unknown. To address the role of lipid metabolism in prostate cancer, we have used etomoxir and orlistat, clinically safe drugs that block lipid oxidation and lipid synthesis/lipolysis, respectively. Etomoxir is an irreversible inhibitor of the carnitine palmitoyltransferase (CPT1) enzyme that decreases β oxidation in the mitochondria. Combinatorial treatments using etomoxir and orlistat resulted in synergistic decreased viability in LNCaP, VCaP, and patient-derived benign and prostate cancer cells. These effects were associated with decreased androgen receptor expression, decreased mTOR signaling, and increased caspase-3 activation. Knockdown of CPT1A enzyme in LNCaP cells resulted in decreased palmitate oxidation but increased sensitivity to etomoxir, with inactivation of AKT kinase and activation of caspase-3. Systemic treatment with etomoxir in nude mice resulted in decreased xenograft growth over 21 days, underscoring the therapeutic potential of blocking lipid catabolism to decrease prostate cancer tumor growth. Mol Cancer Ther; 13(10); 2361–71. ©2014 AACR.
Data from Daurinol Enhances the Efficacy of Radiotherapy in Lung Cancer via Suppression of Aurora Kinase A/B Expression
Authors: Woo Jong Kyu , Kang Ju-Hee , Shin DongYun , Park Seong-Hyeok , Kang Kyungsu , Nho Chu Won , Seong Je Kyung , Lee Sang-Jin , Oh Seung Hyun
Published: March 2024

Abstract
The aurora kinases constitute one family of serine/threonine kinases whose activity is essential for mitotic progression. The aurora kinases are frequently upregulated in human cancers and are associated with sensitivity to chemotherapy in certain ones. In the present study, we investigated whether aurora kinases could be a target to overcome radioresistance or enhance the radiosensitivity of lung cancer. For that purpose, we determined the therapeutic potential of daurinol, an investigational topoisomerase inhibitor, alone and in combination with radiation, by observing its effect on aurora kinases. Daurinol decreased cell viability and proliferation in human colon and lung cancer cells. Gene expression in daurinol-treated human colon cancer cells was evaluated using RNA microarray. The mRNA expression of 18 genes involved in the mitotic spindle check point, including aurora kinase A (AURKA) and aurora kinase B (AURKB), was decreased in daurinol-treated human colon cancer cells as compared with vehicle-treated cells. As expected, radiation increased expression levels of AURKA and AURKB. This increase was effectively attenuated by siRNAs against AURKA and AURKB, which suppressed cell growth and increased apoptosis under radiation. Furthermore, the expression of AURKA and AURKB was suppressed by daurinol in the presence or absence of radiation in colon and lung cancer cells. Daurinol alone or in combination with radiation decreased lung cancer growth in xenograft mouse models. Our data clearly confirm the antitumor and radiosensitizing activity of daurinol in human lung cancer cells through the inhibition of AURKA and AURKB. Mol Cancer Ther; 14(7); 1693–704. ©2015 AACR.
Data from Preclinical Profile of the HER2-Targeting ADC SYD983/SYD985: Introduction of a New Duocarmycin-Based Linker-Drug Platform
Authors: Dokter Wim , Ubink Ruud , van der Lee Miranda , van der Vleuten Monique , van Achterberg Tanja , Jacobs Danielle , Loosveld Eline , van den Dobbelsteen Diels , Egging David , Mattaar Ellen , Groothuis Patrick , Beusker Patrick , Coumans Ruud , Elgersma Ronald , Menge Wiro , Joosten John , Spijker Henri , Huijbregts Tijl , de Groot Vincent , Eppink Michel , de Roo Guy , Verheijden Gijs , Timmers Marco
Published: March 2024

Abstract
A linker-drug platform was built on the basis of a cleavable linker-duocarmycin payload for the development of new-generation antibody–drug conjugates (ADC). A leading ADC originating from that platform is SYD983, a HER2-targeting ADC based on trastuzumab. HER2-binding, antibody-dependent cell-mediated cytotoxicity and HER2-mediated internalization are similar for SYD983 as compared with trastuzumab. HER2-expressing cells in vitro are very potently killed by SYD983, but SYD983 is inactive in cells that do not express HER2. SYD983 dose dependently reduces tumor growth in a BT-474 mouse xenograft in vivo. The ADC is stable in human and cynomolgus monkey plasma in vitro but shows relatively poor stability in mouse plasma due to mouse-specific carboxylesterase. SYD983 could be dosed up to 30 mg/kg in cynomolgus monkeys with high exposure, excellent stability in blood, and without severe toxic effects. The monkey safety study showed no SYD983-induced thrombocytopenia and no induction of peripheral sensory neuropathy, both commonly observed in trials and studies with ADCs based on tubulin inhibitors. Finally, to improve homogeneity, SYD983 was further purified by hydrophobic interaction chromatography resulting in an ADC (designated SYD985) predominantly containing DAR2 and DAR4 species. SYD985 showed high antitumor activity in two patient-derived xenograft models of HER2-positive metastatic breast cancers. In conclusion, the data obtained indicate great potential for this new HER2-targeting ADC to become an effective drug for patients with HER2-positive cancers with a favorable safety profile. More generally, this new-generation duocarmycin-based linker-drug technology could be used with other mAbs to serve more indications in oncology. Mol Cancer Ther; 13(11); 2618–29. ©2014 AACR.
Data from Multiple Molecular Subtypes of Triple-Negative Breast Cancer Critically Rely on Androgen Receptor and Respond to Enzalutamide In Vivo
Authors: Barton Valerie N. , D'Amato Nicholas C. , Gordon Michael A. , Lind Hanne T. , Spoelstra Nicole S. , Babbs Beatrice L. , Heinz Richard E. , Elias Anthony , Jedlicka Paul , Jacobsen Britta M. , Richer Jennifer K.
Published: March 2024

Abstract
Triple-negative breast cancer (TNBC) has the lowest 5-year survival rate of invasive breast carcinomas, and currently there are no approved targeted therapies for this aggressive form of the disease. The androgen receptor (AR) is expressed in up to one third of TNBC and we find that all AR+ TNBC primary tumors tested display nuclear localization of AR, indicative of transcriptionally active receptors. While AR is most abundant in the “luminal AR (LAR)” molecular subtype of TNBC, here, for the first time, we use both the new-generation anti-androgen enzalutamide and AR knockdown to demonstrate that the other non-LAR molecular subtypes of TNBC are critically dependent on AR protein. Indeed, AR inhibition significantly reduces baseline proliferation, anchorage-independent growth, migration, and invasion and increases apoptosis in four TNBC lines (SUM159PT, HCC1806, BT549, and MDA-MB-231), representing three non-LAR TNBC molecular subtypes (mesenchymal-like, mesenchymal stem–like, and basal-like 2). In vivo, enzalutamide significantly decreases viability of SUM159PT and HCC1806 xenografts. Furthermore, mechanistic analysis reveals that AR activation upregulates secretion of the EGFR ligand amphiregulin (AREG), an effect abrogated by enzalutamide in vitro and in vivo. Exogenous AREG partially rescues the effects of AR knockdown on proliferation, migration, and invasion, demonstrating that upregulation of AREG is one mechanism by which AR influences tumorigenicity. Together, our findings indicate that non-LAR subtypes of TNBC are AR dependent and, moreover, that enzalutamide is a promising targeted therapy for multiple molecular subtypes of AR+ TNBC. Mol Cancer Ther; 14(3); 769–78. ©2015 AACR.
Data from Silencing Egr1 Attenuates Radiation-Induced Apoptosis in Normal Tissues while Killing Cancer Cells and Delaying Tumor Growth
Authors: Zhao Diana Yi , Jacobs Keith M. , Hallahan Dennis E. , Thotala Dinesh
Published: March 2024

Abstract
Normal tissue toxicity reduces the therapeutic index of radiotherapy and decreases the quality of life for cancer survivors. Apoptosis is a key element of the radiation response in normal tissues like the hippocampus and small intestine, resulting in neurocognitive disorders and intestinal malabsorption. The Early Growth Response 1 (Egr1) transcription factor mediates radiation-induced apoptosis by activating the transcription of proapoptosis genes in response to ionizing radiation (IR). Therefore, we hypothesized that the genetic abrogation of Egr1 and the pharmacologic inhibition of its transcriptional activity could attenuate radiation-induced apoptosis in normal tissues. We demonstrated that Egr1-null mice had less apoptosis in the hippocampus and intestine following irradiation as compared with their wild-type littermates. A similar result was achieved using Mithramycin A (MMA) to prevent binding of Egr1 to target promoters in the mouse intestine. Abolishing Egr1 expression using shRNA dampened apoptosis and enhanced the clonogenic survival of irradiated HT22 hippocampal neuronal cells and IEC6 intestinal epithelial cells. Mechanistically, these events involved an abrogation of p53 induction by IR and an increase in the ratio of Bcl-2/Bax expression. In contrast, targeted silencing of Egr1 in two cancer cell lines (GL261 glioma cells and HCT116 colorectal cancer cells) was not radioprotective, since it reduced their growth while also sensitizing them to radiation-induced death. Further, Egr1 depletion delayed the growth of heterotopically implanted GL261 and HCT116 tumors. These results support the potential of silencing Egr1 in order to minimize the normal tissue complications associated with radiotherapy while enhancing tumor control. Mol Cancer Ther; 14(10); 2343–52. ©2015 AACR.
Data from A TORC2–Akt Feed-Forward Topology Underlies HER3 Resiliency in HER2-Amplified Cancers
Authors: Amin Dhara N. , Ahuja Deepika , Yaswen Paul , Moasser Mark M.
Published: March 2024

Abstract
The requisite role of HER3 in HER2-amplified cancers is beyond what would be expected as a dimerization partner or effector substrate and it exhibits a substantial degree of resiliency that mitigates the effects of HER2-inhibitor therapies. To better understand the roots of this resiliency, we conducted an in-depth chemical-genetic interrogation of the signaling network downstream of HER3. A unique attribute of these tumors is the deregulation of TORC2. The upstream signals that ordinarily maintain TORC2 signaling are lost in these tumors, and instead TORC2 is driven by Akt. We find that in these cancers HER3 functions as a buffering arm of an Akt–TORC2 feed-forward loop that functions as a self-perpetuating module. This network topology alters the role of HER3 from a conditionally engaged ligand-driven upstream physiologic signaling input to an essential component of a concentric signaling throughput highly competent at preservation of homeostasis. The competence of this signaling topology is evident in its response to perturbation at any of its nodes. Thus, a critical pathophysiologic event in the evolution of HER2-amplified cancers is the loss of the input signals that normally drive TORC2 signaling, repositioning it under Akt dependency, and fundamentally altering the role of HER3. This reprogramming of the downstream network topology is a key aspect in the pathogenesis of HER2-amplified cancers and constitutes a formidable barrier in the targeted therapy of these cancers. Mol Cancer Ther; 14(12); 2805–17. ©2015 AACR.
Data from Concordance of Genomic Alterations by Next-Generation Sequencing in Tumor Tissue versus Circulating Tumor DNA in Breast Cancer
Authors: Chae Young Kwang , Davis Andrew A. , Jain Sarika , Santa-Maria Cesar , Flaum Lisa , Beaubier Nike , Platanias Leonidas C. , Gradishar William , Giles Francis J. , Cristofanilli Massimo
Published: March 2024

Abstract
While identifying genomic alterations in tumor tissue is the current gold-standard technique for molecular profiling, circulating tumor DNA (ctDNA) represents a noninvasive method of assessing genomic alterations using peripheral blood. The concordance of genomic alterations between two commercially available ctDNA and tissue biopsies was compared in 45 patients with breast cancer using paired next-generation sequencing tissue and ctDNA biopsies. Across all genes, concordance between the two platforms was 91.0% to 94.2%. When only considering genomic alterations in either assay (e.g., excluding wild type/wild type genes), concordance was 10.8% to 15.1% with full plus partial concordance of 13.8% to 19.3%. Concordant mutations were associated with significantly higher variant allele frequency. Over half of mutations detected in either technique were not detected using the other biopsy technique. Including variants of unknown significance, the average number of alterations per patient was significantly higher for tissue (4.56) compared with ctDNA (2.16). When eliminating alterations not detectable in the ctDNA assay, mean number of alterations for tissue and ctDNA was similar (2.67 for tissue, 2.16 for ctDNA). Across five representative genes (TP53, PIK3CA, ERBB2, BRCA1, and BRCA2), sensitivity and specificity were 35.7% and 95.0%, respectively. Concordance when genomic alterations was detected in either tissue or ctDNA was low with each technique detecting a significant amount of nonoverlapping mutations. Potential explanations for the lack of concordance include tumor heterogeneity, different sequencing techniques, spatial and temporal factors, and potential germline DNA contamination. The study indicates that both tissue and blood-based NGS may be necessary to describe the complex biology of breast cancer. Mol Cancer Ther; 16(7); 1412–20. ©2017 AACR.