bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4641: Bone marrow stromal cells frustrate temozolomide treatment of glioblastoma
Authors: Katakowski Mark , Pikula Elizabeth , Kalkanis Steven , Chopp Michael
Published: July 2016

Temozolomide (TMZ) is the most widely used for the treatment of glioblastoma. However, despite the effectiveness of TMZ, progression and recurrence are observed in nearly all patients. Here, we report a heretofore unknown mechanism of TMZ chemo-resistance mediated by circulating exosomes. Exosomes are small microvesicles released by cells that efficiently transfer their molecular cargo to other cells, including tumor. We recently found that in response to TMZ treatment, human bone marrow stromal cells (MSCs) release exosomes that confer TMZ chemo-resistance upon glioblastoma cells.

MSCs produce exosomes which can be found in circulating blood. TMZ is distributed systemically, thus we tested the effect of TMZ upon MSC-produced exosomes, and the profile of miRNAs within the exosomes. In addition, we tested if MSC exosomes altered the response of glioblastoma cells to TMZ. To test our hypotheses, we treated MSCs with TMZ, and performed miRNA PCR arrays upon exosomes produced by the MSCs (tMSC-exo). Furthermore, we exposed glioblastoma cells to tMSC-exo, and measured the effect upon tumor cell viability, and growth in the presence of TMZ. Finally, we collected serum exosomes from patients with glioblastoma upon resection, and after TMZ treatment. We tested if exosomes from these patients before and after TMZ treatment exhibit different chemo-resistive effects, and if TMZ treatment altered the miRNA profile in circulating exosomes.

We report that tMSC-exo elicit a protective effect upon glioblastoma cells treated with TMZ. The miRNA profile of MSC exosomes was also significantly altered by TMZ. Like MSC exosomes, TMZ treatment altered the miRNA profile of circulating exosomes in glioblastoma patients, and resulted in increased chemo-resistance conferred by the exosomes upon tumor cells.

Investigations of TMZ chemo-resistance have largely focused upon characteristics of the tumor cells the agent is intended to kill. Here, we elucidate a novel mechanism of resistance to TMZ which does not arise from the tumor itself. Our findings suggest that circulating exosomes may diminish the efficacy of TMZ treatment of glioblastoma.

Citation Format: Mark Katakowski, Elizabeth Pikula, Steven Kalkanis, Michael Chopp. Bone marrow stromal cells frustrate temozolomide treatment of glioblastoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4641.
Abstract 4653: Combination Azacitidine and histone deacetylase inhibition induces a multi factorial synergistic anti-tumor response in non-small cell lung cancer (NSCLC)
Authors: Topper Michael , Hanigan Christin , Vaz Michelle , Chiappinelli Katherine , Justin Julin , Murphy Lauren , Zahnow Cynthia , Baylin Stephen
Published: July 2016

Epigenetic therapy holds much promise as an emerging paradigm for the treatment of many disparate types of human cancer. However, the data in solid malignancies, particularly, would suggest further optimization is required to extract the true potential of these therapies. In our current study, we have deployed at low, clinically achievable doses, chronic combinatorial administration of the DNA methyltransferase inhibitor Azacitidine in conjunction with both benzamide and hydroxyamic acid based histone deacetylase inhibitors (HDACi) in NSCLC. We have developed our paradigms by sequentially employing chronic HDACi administration after Azacitidine. This strategy achieves durable alteration of the cell transcriptome with corresponding induction of both cell cycle arrest and apoptosis. These events appear driven by alterations, both transcriptionally and post transcriptionally of Myc and Myc regulatory proteins. Epigenetic treatment induced perturbation of Myc is facilitated by Wnt pathway inhibition through induction of Wnt antagonists, namely DKK proteins. Importantly, as part of this scenario of altering a Myc regulatory axis, there is a synergistic cytotoxic response mediated at least in part through downregulation of a critical effector, the Skp2 oncogene. Additionally, we observe significant induction of an interferon responsive viral defense gene signature as the result of epigenetic treatment. This gene signature has been shown to correlate with response to immune checkpoint blockade in the setting of metastatic melanoma. We propose that this combination of viral defense gene signature augmentation in conjunction with potent direct epithelial cancer cytotoxicity holds promise to be a more complete therapeutic paradigm for the treatment of NSCLC.

Citation Format: Michael Topper, Christin Hanigan, Michelle Vaz, Katherine Chiappinelli, Julin Justin, Lauren Murphy, Cynthia Zahnow, Stephen Baylin. Combination Azacitidine and histone deacetylase inhibition induces a multi factorial synergistic anti-tumor response in non-small cell lung cancer (NSCLC). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4653.
Abstract 4681: Oseltamivir phosphate completely ablates tumor refractoriness to conventional chemotherapeutics abraxane and gemcitabine in xenografts of tumors in mouse model of human pancreatic cancer
Authors: Szewczuk Myron R.
Published: July 2016

Pancreatic cancer, the fourth leading cause of cancer-related death worldwide, is highly aggressive and associated with a poor prognosis. Resistance to drug therapy, along with high rates of metastasis, contributes to the low survival rates in patients diagnosed with pancreatic cancer. Gemcitabine, a chemotherapeutic agent, is the current standard of care for patients with the disease. Although gemcitabine has higher success rates than any other chemotherapeutic in use, patients receiving gemcitabine still only have progression-free survival in the range of 0.9-4.2 months. Given the poor response rate to gemcitabine, pancreatic cancer cells develop rapid resistance to this drug. Here, we investigated the proof of concept for a reported entirely new anticancer drug, oseltamivir phosphate (OP), to overcome tumor refractoriness to gemcitabine and abraxane in heterotopic xenografts of pancreatic MiaPaCa-2 tumors growing in RAGxCγ double mutant mice. The data clearly indicate that mice treated with 50mg/kg abraxane alone (1x weekly, i.p.) at Day 33 post implantation slightly restrained tumor growth until Day70 at which time the tumor developed resistance to abraxane and rapidly increased in tumor volume and spread to the lungs. In contrast, abraxane in combination with OP 20mg/kg (3x weekly, i.p.) abrogated the tumor resistance to abraxane and impeded tumor growth and metastatic spread to the lung. Very interestingly, with comparable results to abraxane/OP, mice treated with 30mg/kg gemcitabine (1x weekly, i.p.) at Day31 post implantation developed tumor resistance at Day50 to gemcitabine and rapidly increased in tumor volume and spread to the lung. Gemcitabine in combination with 20mg/kg OP (3x weekly, i.p.) completely impeded the tumor growth, chemoresistance and spread to the lungs with long term survival at Day 240 with no relapse and metastasis. The significance of these findings is the first to show that OP in combination with standard, clinical chemotherapeutics can impede (a) human pancreatic tumor growth, (b) tumor neovascularization, (c) liver and lung metastases, and (d) tumor refractoriness to conventional chemotherapeutics, as well (e) significantly extending survival rates with no relapse and metastasis.

Citation Format: Myron R. Szewczuk. Oseltamivir phosphate completely ablates tumor refractoriness to conventional chemotherapeutics abraxane and gemcitabine in xenografts of tumors in mouse model of human pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4681.
Abstract 4695: Functional group elaboration of a low molecular weight fragment to yield the novel BET family bromodomain inhibitor ABBV-075
Authors: McDaniel Keith , Wang Le , Sheppard George , Fidanze Steve , Pratt John , Liu Dachun , Hasvold Lisa , Mantei Robert , Park Chang , Sarthy Aparna , Li Leiming , Albert Daniel H. , Lin Xiaoyu , Warder Scott , Faivre Emily , Bui Mai H. , Huang Xiaoli , Wilcox Denise , Wang Rongqi , Magoc Terry , Rajaraman Ganesh , Petros Andrew , Panchal Sanjay , Sun Chaohong , Fang Guowei , Elmore Steven W. , Rosenberg Saul , Shen Yu , Kati Warren
Published: July 2016

Phenotypic cell-based screening assays combined with affinity chromatography and mass-spectrometry identified the BET family of bromodomains as potential targets for blocking proliferation in a variety of cancer cell lines. Lead-finding investigations included screening a library of compounds with an average molecular weight of 225 for binding to the 13C-labeled 2nd bromodomain of BRD4 using 2-dimensional NMR. A pyridazinone fragment emerged from this effort that possessed weak binding affinity (Kd = 130 uM). The binding affinity was improved by roughly 100,000-fold through an X-ray structure enabled medicinal chemistry program that included moving to a pyrrolopyridone core along with judicious placement of additional functional groups. Antiproliferative potencies strongly correlated with potencies in a cell-based target engagement assay, suggesting that the antiproliferative effects resulted from the inhibition of BRD4/BET protein function. In vitro metabolite ID studies in rat liver microsomes helped identify sites of oxidative metabolism. The addition of fluorine atoms at these locations improved rat in vitro microsomal stability that translated to low in vivo clearance and high oral exposure in rat. The final molecule, ABBV-075, exhibited long half-lives and low unbound clearances in rat, mouse, dog and monkey. ABBV-075 demonstrated significant tumor growth inhibition in mouse flank xenograft studies representing diverse hematological and solid tumor malignancies and recently entered Phase I clinical studies.

Disclosures:

All authors are employees of AbbVie. The design, study conduct, and financial support for this research were provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the publication.

Citation Format: Keith McDaniel, Le Wang, George Sheppard, Steve Fidanze, John Pratt, Dachun Liu, Lisa Hasvold, Robert Mantei, Chang Park, Aparna Sarthy, Leiming Li, Daniel H. Albert, Xiaoyu Lin, Scott Warder, Emily Faivre, Mai H. Bui, Xiaoli Huang, Denise Wilcox, Rongqi Wang, Terry Magoc, Ganesh Rajaraman, Andrew Petros, Sanjay Panchal, Chaohong Sun, Guowei Fang, Steven W. Elmore, Saul Rosenberg, Yu Shen, Warren Kati. Functional group elaboration of a low molecular weight fragment to yield the novel BET family bromodomain inhibitor ABBV-075. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4695.
Abstract 4704: The evaluation of INCB059872, an FAD-directed inhibitor of LSD1, in preclinical models of human small cell lung cancer
Authors: Lee Sang Hyun , Liu Xuesong Mike , Diamond Melody , Dostalik Valerie , Favata Margaret , He Chunhong , Wu Liangxing , Wynn Richard , Yao Wenqing , Hollis Gregory , Huber Reid , Scherle Peggy , Ruggeri Bruce
Published: July 2016

Methylated histone marks on H3K4 and H3K9 are generally coupled with transcriptional activation and repression, respectively. Altered levels of these histone methylation marks lead to abnormal gene expression and are associated with oncogenesis. Lysine specific demethylase 1 (LSD1) catalyzes demethylation of mono and di-methylated lysine 4 and 9 of histone H3 via an FAD-dependent redox-process. Deregulated LSD1 activity perturbs normal gene expression and can lead to cellular transformation. In particular, the function of LSD1 has been reported to maintain stem cell-like gene expression patterns in various cancers, most notably small cell lung cancer (SCLC), a cancer type that is characterized by a highly undifferentiated state and with high unmet medical need. INCB059872 is a potent, selective and orally bioavailable inhibitor of LSD1 that achieves inhibitory activity through the formation of covalent FAD-adducts. The effect of INCB059872 in SCLC cell lines was assessed in vitro and in vivo. In these studies, the proliferation of a panel of SCLC cell lines was inhibited by INCB059872, with EC50 values ranging from 47 to 377 nM. Non-tumorigenic cells, such as IL-2 stimulated T cells from normal donors, by contrast, were significantly less sensitive with IC50 values > 10 μM. Oral administration of INCB059872 on once daily (QD) and alternative day (QoD) dosing regimens inhibited tumor growth in the NCI-H526 and NCI-H1417 human SCLC xenograft models. Consistent with previous reports, INCB059872 treatment in these models led to the induction of the FEZ1 and UMODL1 genes relative to vehicle-treated animals, as part of a gene signature in SCLC cell lines that is predictive of LSD1 responsiveness. Moreover, serum levels of the neuroendocrine marker pro-GRP were markedly reduced at all efficacious dosing regimens in the NCI-H1417 human SCLC xenograft model, suggesting that serum pro-GRP levels could be used as a surrogate pharmacodynamic marker of LSD1 inhibition. Currently, the efficacy of INCB059872 in combination with standard of care therapies for SCLC is under evaluation in these preclinical models. These data support the clinical evaluation of INCB059872 in patients with SCLC.

Citation Format: Sang Hyun Lee, Xuesong Mike Liu, Melody Diamond, Valerie Dostalik, Margaret Favata, Chunhong He, Liangxing Wu, Richard Wynn, Wenqing Yao, Gregory Hollis, Reid Huber, Peggy Scherle, Bruce Ruggeri. The evaluation of INCB059872, an FAD-directed inhibitor of LSD1, in preclinical models of human small cell lung cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4704.
Abstract 4722: Selective inhibition of DNA methyltransferases and efficacy of novel DNMT inhibitors in leukemia xenografts
Authors: Nguyen Dat , Hollingshead Melinda , Rubinstein Larry , Doroshow James , Yang Sherry X.
Published: July 2016

Background. DNA methyltransferase (DNMT) 1 plays an important role in tumorigenesis and is responsible for maintenance and propagation of DNA methylation patterns, and DNMT3A and DNMT3B are involved in de novo DNA methylation. 4’-Thio-5-aza-2’-deoxycytidine (5-aza-T-dCyd) and 4’-thio-2’-deoxycytidine (T-dCyd) are novel DNMT inhibitors in development. In this investigation, we test the hypothesis that DNMTs are differentially modulated by DNMT inhibitors that may contribute to treatment efficacy. Methods. Animals (5 per group) bearing HL-60 leukemia cell xenografts were treated with saline or aza-T-dCyd at 2 mg/kg with and without 100 mg/kg tetrahydrouridine (ThU) for 5 days weekly for 2 weeks and cycle repeat after 9-day rest. Two other groups were dosed with T-dCyd at 4 mg/kg and decitabine at 0.75 mg/kg, respectively. Tumor growth was assessed by measuring tumor size. Expression of DNMT1, DNMT3A and DNMT3B was examined by immunohistochemistry in paraffin-embedded tumors resected at day 11. Results. Expression of DNMT1 was high, DNMT3B intermediate, and DNMT3A at low levels in saline control group. Significant growth delay was achieved in the aza-T-dCyd (86%) and aza-T-dCyd plus ThU cohorts (45%), compared with the controls. In the aza-T-dCyd treated xenografts, histological examination confirmed a significant reduction (77%) in tumor area (P = 0.002). Expression of DNMT1 and DNMT3B (n = 2 in aza-TdCyd group) was reduced in aza-T-dCyd cohort (P = 0.01 and P = 0.04) as well as aza-T-dCyd in combination with ThU group (P = 0.01 and P = 0.03). In contrast, no growth inhibition but decrease in DNMT3A and DNMT1 were observed by dosing with decitabine. There were neither delays for tumor growth nor changes of all three DNMTs by T-dCyd treatment with the dose administered. Conclusions. Aza-T-dCyd and aza-T-dCyd plus ThU treatments result in significant tumor growth inhibition in HL-60 leukemia xenografts. The anti-tumor activity is associated with simultaneous inhibition of the two drug targets — DNMT1 and DNMT3B. The preclinical results provide compelling evidence to advance aza-T-dCyd for clinical development and perhaps in the context of companion biomarker approach.

Citation Format: Dat Nguyen, Melinda Hollingshead, Larry Rubinstein, James Doroshow, Sherry X. Yang. Selective inhibition of DNA methyltransferases and efficacy of novel DNMT inhibitors in leukemia xenografts. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4722.
Abstract 4726: Inhibitors of histone deacetylase 1 reverse the immune evasion phenotype to enhance T-cell-mediated lysis of prostate and breast carcinoma cells
Authors: Gameiro Sofia R. , Malamas Anthony S. , Fantini Massimo , Tsang Kwong Y. , Ferrone Soldano , Hodge James W.
Published: July 2016

The clinical promise of cancer immunotherapy relies on the premise that the immune system can effectively recognize and eliminate tumor cells identified as non-self. However, tumors can evade host immune surveillance through multiple mechanisms, including epigenetic silencing of genes involved in antigen processing and immune recognition. Hence, there is an unmet clinical need to develop effective therapeutic strategies that can restore tumor immune recognition and thus promote long-lasting tumor control when combined with immunotherapy, such as immune checkpoint blockade and therapeutic cancer vaccines. Although epigenetic therapies have shown limited clinical benefit for patients harboring solid tumors, recent clinical reports suggest a strong potential for clinical synergy when combined with immunotherapy. We sought to examine the potential of clinically relevant exposure of prostate and breast human carcinoma cells to histone deacetylase (HDAC) inhibitors to reverse tumor immune escape to T-cell mediated lysis. Here we demonstrate that prostate and breast carcinoma cells are more sensitive to T-cell mediated lysis in vitro after clinically relevant exposure to epigenetic therapy with either the pan-HDAC inhibitor vorinostat or the class I HDAC inhibitor entinostat. This pattern of immunogenic modulation was observed against a broad range of tumor-associated antigens, such as CEA, MUC-1, PSA, and brachyury, and associated with augmented expression of multiple proteins involved in antigen processing and tumor immune recognition. Genetic and pharmacological inhibition studies identified HDAC1 as a key determinant in the reversal of carcinoma immune escape. Further, our findings suggest that the observed reversal of tumor immune evasion is driven by a response to cellular stress through activation of the unfolded protein response. This offers the rationale for combining HDAC inhibitors with immunotherapy, including therapeutic cancer vaccines.

Citation Format: Sofia R. Gameiro, Anthony S. Malamas, Massimo Fantini, Kwong Y. Tsang, Soldano Ferrone, James W. Hodge. Inhibitors of histone deacetylase 1 reverse the immune evasion phenotype to enhance T-cell-mediated lysis of prostate and breast carcinoma cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4726.
Abstract 473: A tumor and immune related miRNA signature predicts progression-free survival of melanoma patients treated with ipilimumab
Authors: Tarhini Ahmad , Vallabhaneni Priyanka , Floros Theofanis , LaFramboise William A. , Benos Panayiotis V. , Santana dos Santos. Lucas
Published: July 2016

Background

Patients with regionally advanced melanoma were treated with neoadjuvant ipilimumab in a previously reported study (Tarhini et al, PLOS One 2014). MicroRNA (miRNA) expression profiles of tumors of treated patients were investigated for their therapeutic predictive value.

Methods

Patients were treated with ipilimumab (10 mg/kg IV every 3 weeks x2 doses) bracketing surgery. Tumor specimens were obtained at baseline and following ipilimumab at definitive surgery (week 6-8). MiRNA expression profiling was performed on the tumor biopsies of 30 patients using Affymetrix miRNA array (v.4). Significance Analysis of Microarrays (SAM) was performed to test the association of each differentially expressed miRNA molecule with outcome. Targets of the selected miRNAs were obtained from miRTarBase (http://mirtarbase.mbc.nctu.edu.tw). Functional annotation analysis of the list of miRNA target genes were performed using DAVID (https://david.ncifcrf.gov). The FDR method was used to adjust for multiple testing in SAM and the functional analysis.

Results

An expression profile consisting of a 4-miRNA signature was associated with improved progression free survival. The signature consisted of miR-34c (previously reported to suppress cancer growth and invasion), miR-711 (reported as a prognostic marker in cutaneous T-cell lymphomas and to target and suppress Heat Shock Protein 70 highly expressed in melanoma), miR-641 (activates MAPK by targeting NF1 and cooperates with its host gene AKT2 in human cancer) and miR-22 (reported to function as a tumour suppressor). Functional annotation analysis of target genes for the 4-miRNA signature was statistically significantly enriched for various cancer-related pathways including regulation of cell proliferation (GO:0042147), regulation of apoptosis (GO:0042981), MAPK signaling pathway (hsa04010) and positive regulation of T cell activation (GO:0050870).

Conclusions

MiRNA expression profiling identified a 4-miRNA signature that is significantly associated with PFS in advanced melanoma patients treated with neoadjuvant ipilimumab. Preliminary results show that targets of these 4 miRNAs are biologically relevant and important. These findings warrant further investigation in relation to ipilimumab and other immunotherapeutics.

Citation Format: Ahmad Tarhini, Priyanka Vallabhaneni, Theofanis Floros, William A. LaFramboise, Panayiotis V. Benos, Lucas Santana dos Santos. A tumor and immune related miRNA signature predicts progression-free survival of melanoma patients treated with ipilimumab. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 473.
Abstract 4731: Targeted therapies for prostate cancer: Strategies for efficient combinatorial approaches
Authors: Butt Nasir A. , Dhar Swati , Kumar Avinash , Rimando Agnes M. , Zhang Xu , Levenson Anait S.
Published: July 2016

Metastasis-associated protein 1(MTA1) is a cancer progression- related epigenetic regulator, which is overexpressed in hormone-refractory and metastatic prostate cancer (PCa). MTA1/HDAC unit is a part of the multi-protein nucleosome remodeling and deacetylation (NuRD) complex. In our previous studies we found that MTA1 expression is significantly increased in prostate-specific Pten-null model, and that potent natural analog of resveratrol, pterostilbene (PTER), exerts its anti-tumorigenic effects by blocking MTA1-associated inactivation (deacetylation) of tumor suppressors. SAHA (suberoylanilide hydroxamine, vorinostat) is a histone deacetylase (HDAC) inhibitor that has been shown to be an effective inhibitor of tumor cell growth. We hypothesize that targeting MTA1/HDAC unit of NuRD complex using PTER in combination with SAHA could act additively or synergistically to block prostate tumor progression in vivo with higher efficacy and lower toxicity. In the current study, we utilized the prostate-specific Pten-null mouse model to evaluate the MTA1/HDAC mediated anti-cancer efficacy of combinatorial approach for dietary PTER and clinically approved HDAC inhibitor, SAHA. After a series of carefully designed breeding strategies and genotyping, we collected 30 prostate-specific luciferase expressing Pten knockout (Pten f/f; Rosa26Luc/+; Pb-Cre4) male mice for our experiments. Prostate-specific luciferase expression allowed non-invasive monitoring of prostate tumor growth in these animals. Mice were randomized into four groups: Vehicle control (10% DMSO); PTER (10 mg/kg bw) alone, SAHA (50 mg/kg bw) alone, and PTER + SAHA. Compounds were injected daily, i.p., starting at 8 weeks of age. Mice were sacrificed at week 18. Histopathological (H&E, SMA, CK-8), immunohistochemical (Ki-67, cleaved caspase-3, CD31) and molecular evaluation (MTA1, pAkt, AR) of prostate tissues showed beneficial effects of treatments alone and more so in combination compared to the control group.

Citation Format: Nasir A. Butt, Swati Dhar, Avinash Kumar, Agnes M. Rimando, Xu Zhang, Anait S. Levenson. Targeted therapies for prostate cancer: Strategies for efficient combinatorial approaches. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4731.
Abstract 4752: Overexpression of enhancer of zeste homolog 2 (EZH2) in endometrial carcinoma: evidence from an NRG Oncology/Gynecologic Oncology Group trial
Authors: Krill Lauren , Ali Shamshad , Eskander Ramez , Singh Meenakshi , Mutch David , Zweizig Susan , Birrer Michael , Lankes Heather , Hoang Bang , Randall Leslie
Published: July 2016

Objectives: Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase that mediates epigenetic silencing of tumor suppressor genes. It is commonly over-expressed in several solid tumors and has been shown to be a prognostic biomarker in breast, renal, and gastric cancers. This study aims to investigate patterns of EZH2 expression in endometrial cancer.

Methods: Evaluation of expression of EZH2 was completed on both early and advanced stage endometrioid adenocarcinoma tissues and a subset of matched normal mullerian tissue samples, from participants enrolled in GOG protocol 210, using real time reverse transcription polymerase chain reaction (RT-PCR) and western blot (WB) analysis. Investigators were blinded to clinical data. One-way ANOVA, F test and Fisher's exact test were used to assess differences in log mRNA and protein expression respectively with known clinical and pathologic prognostic factors. Kaplan Meier survival analysis was used to evaluate differences in progression free survival (PFS) based on EZH2 expression.

Results: Eight-seven specimens were analyzed including 60 tumors and 27 normal tissue specimens. EZH2 mRNA and protein expression in tumor specimens was significantly higher than in matched controls (paired t test, p < 0.001). EZH2 expression was associated with lympho-vascular space invasion (p = 0.044) but other clinical and pathologic factors including age, stage, grade, nodal involvement or disease status were not associated with significant differences in expression. However, there does appear to be a trend towards decreased progression free survival among patients with increased EZH2 expression levels.

Conclusions: Our results confirm that there is differential expression of EZH2 in uterine cancers compared to normal tissues and suggests a potential role of the EZH2 as prognostic marker of aggressive disease in patients with endometrial cancer. In view of the substantial portion of early stage low grade tumors expressing EZH2, it will be interesting to investigate if increased EZH2 protein levels may also have therapeutic implications, since targeted inhibition of EZH2 expression has been shown to repress tumor cell growth in other solid malignancies. Further investigation into this potential prognostic biomarker and therapeutic target is warranted.

Citation Format: Lauren Krill, Shamshad Ali, Ramez Eskander, Meenakshi Singh, David Mutch, Susan Zweizig, Michael Birrer, Heather Lankes, Bang Hoang, Leslie Randall. Overexpression of enhancer of zeste homolog 2 (EZH2) in endometrial carcinoma: evidence from an NRG Oncology/Gynecologic Oncology Group trial. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4752.
Abstract 4756: N-cadherin signaling predicts prognosis in medulloblastoma subtypes
Authors: Sverdlov Maria , Downing Michael P. , Kang Shuqi , Chenn Anjen
Published: July 2016

Identification of signaling pathways that drive the clinical behavior of tumors will guide specific molecular therapies. Medulloblastoma, the most common malignant pediatric solid tumor, shows considerable clinical and molecular diversity, providing impetus for specific targeted therapies of predicted molecular drivers. Here we show a gene signature derived from in vitro experimental inhibition of N-cadherin in medulloblastoma (MB) cells predicts survival in human MB in two large independent patient cohorts. Patients with high N-cadherin signature scores had earlier death and reduced overall survival. We found novel heterogeneity in proposed MB molecular subgroups, with significant differences in survival predicted by the N-cadherin signature in sonic hedgehog (SHH) and c2 tumors. In cultured MB cells, N-cadherin cell-cell interactions activated beta-catenin signaling and increased expression of the cancer stem cell regulator Sox2, known to be critical in the growth and relapse of SHH MB. Inhibition of N-cadherin reduced beta-catenin signaling and Sox2. Together, these findings indicate N-cadherin activity predicts the survival of patients with MB and suggest that differential activity of cellular pathways can identify novel disease subgroups and reveal molecular mechanisms with therapeutic significance. 

Citation Format: Maria Sverdlov, Michael P. Downing, Shuqi Kang, Anjen Chenn. N-cadherin signaling predicts prognosis in medulloblastoma subtypes. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4756.
Abstract 4775: Astrocyte elevated gene-1(AEG-1)as a potential diagnostic/prognostic marker for prostate cancer
Authors: Andavolu Radhika Gade , Stafford Catherine , Herling Patrick , Bianco Isabella , Cardenas Jean-Luc , Go Henry , Rubakovic Svetlana , Andavolu Murthy V.
Published: July 2016

AEG-1/MTDH/LYRIC was initially identified as a HIV-1-inducible gene in primary human fetal astrocytes. Astrocyte Elevated Gene-1 (AEG-1) is ubiquitously overexpressed in all or most cancers and plays a regulatory role in diverse and multiple processes of carcinogenesis. AEG1 is a multi-functional regulator of normal and abnormal physiology; it contributes to broad-spectrum resistance to various chemotherapeutics; and it was recently proposed as the first potential ‘pan-cancer’ gene However, despite its critical relevance to carcinogenesis, until now genetic polymorphisms for this important gene have not been studied for association with cancer susceptibility. For example, though studies have reported AEG-1 gene expression in animal models and tumor tissues, no studies have been reported in Caucasians on the AEG-1 gene polymorphisms in large samples to establish an association with cancers. We report a PCR-RFLP screening protocol for AEG-1 gene polymorphism which is cost effective, simple and reproducible. This study also shows the strong association of AEG-1 gene with prostate cancer risk and metastasis.

DNA and RNA was isolated from 232 normal healthy age matched male Caucasians and 129 prostate cancer patients recruited in the study with an informed consent. AEG-1 gene polymorphism (rs2438211) was screened using PCR-RFLP method. Patients were compared with normal healthy controls and also within patient group comparisons were made between primary and metastasis cases. Genotype analysis was done using IBM SPSS 22 software and gene expression analysis was done using RT2 profiler PCR Array Data analysis version 3.5 (SABIOSCIENCES).

A strong association of AEG-1 gene polymorphism with prostate cancer (p<0.0001) was observed. A high frequency of the mutant allele was observed in patients (27%) as compared to normal healthy controls (7.9%).This study also highlights the possible effect of AEG-1 interaction with other genes (p53, BCCIP) contributing to tumorigenesis.

Citation Format: Radhika Gade Andavolu, Catherine Stafford, Patrick Herling, Isabella Bianco, Jean-Luc Cardenas, Henry Go, Svetlana Rubakovic, Murthy V. Andavolu. Astrocyte elevated gene-1(AEG-1)as a potential diagnostic/prognostic marker for prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4775.
Abstract 4776: Dichloro [4,40-bis(4,4,4-trifluorobutyl)-2,20-bipyridine] platinum, a novel Cisplatin analog, exhibits enhanced anticancer activity in preclinical models of upper gastrointestinal cancers
Authors: Bapat Samhita , Dichwalkar Tanmay , Pancholi Priya , Bennett Byron L. , Sehdev Vikas
Published: July 2016

Background: Upper Gastrointestinal Cancers (UGCs) respond poorly to conventional chemotherapy due to variable P53 status and overactive mechanisms that mediate drug resistance. Platinum based compounds like Cisplatin (CDDP) are frequently used for treatment of UGCs. However, clinical use of CDDP is limited due to development of drug resistance and dose limiting side-effects resulting in nausea, vomiting, neutropenia, thrombocytopenia and renal toxicity. In this study we investigated the anticancer potency of a novel CDDP derivative (dichloro [4,40-bis(4,4,4-trifluorobutyl)-2,20-bipyridine] platinum) (DCTF-CDDP) and compared it to CDDP in P53 wild type and mutant models of UGCs. Methods: For this study, we evaluated the effect of CDDP or its derivative (DCTF-CDDP) on AGS (P53 wild type) and FLO-1 (P53 mutant) UGC cell viability, survival, and expression of apoptotic markers. Results: The cell viability data indicated that DCTF-CDDP treatment was comparatively more effective than CDDP at inhibiting AGS (CDDP IC50: 6.3 ± 0.2 μM; DCTF IC50: 1.7 ± 0.5μM) and FLO-1 (CDDP IC50: 2.5 ± 0.68 μM; DCTF IC50: 0.5 ± 0.6μM) UGC cancer cell viability. The clonogenic cell survival assay data also showed that DCTF-CDDP was significantly (p<0.05) more potent at suppressing UGC cell survival when compared to CDDP. Similarly, the western blot data also showed that treatment with increasing concentrations (1, 2.5, and 5 μM) of CDDP and DCTF-CDDP for 24h induced higher levels of P53/P73 and cleaved PARP with DCTF-CDDP treatment in UGC cells. Conclusions: Our in vitro data indicate that DCTF-CDDP is significantly more potent at inhibiting cell viability and inducing apoptosis in P53 wild type and mutant UGC cells. Our study suggests that DCTF-CDDP could be an effective CDDP derivative that can be used to achieve better therapeutic outcome at lower doses and toxic side effects.

Citation Format: Samhita Bapat, Tanmay Dichwalkar, Priya Pancholi, Byron L. Bennett, Vikas Sehdev. Dichloro [4,40-bis(4,4,4-trifluorobutyl)-2,20-bipyridine] platinum, a novel Cisplatin analog, exhibits enhanced anticancer activity in preclinical models of upper gastrointestinal cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4776.
Abstract 4777: The role of BAG3 in human leukemia cells’ response to the experimental anticancer drug laromustine
Authors: Rice Kevin P. , Loya Amanda J. , Gross Kayla M.
Published: July 2016

The experimental anticancer drug laromustine, which demonstrates moderate clinical efficacy against acute myelogenous leukemia and glioblastoma multiforme, yields two reactive electrophiles in situ. Therapeutic cytotoxicity is principally due to a 2-chloroethylating species that can cause lethal DNA crosslinks. However, the second electrophile, methyl isocyanate, triggers acute toxicity in cultured cancer cells and synergizes with the cogenerated 2-chloroethylating activity. The mechanism by which laromustine kills cancer cells likely includes apoptosis. We measured changes in transcription for 88 genes relating to this cell death pathway cultured human promyelocytic (HL-60) cells using quantitative real-time reverse transcriptase PCR. Cultured cells were treated with drug for six hours before harvesting mRNA for analysis. Of these genes, the expression of BAG3, whose encoded protein is also known as CAIR-1 or Bis, was increased by more than 300 fold in cells exposed to laromustine. By forming a complex with heat shock protein 70 (Hsp70), it is thought that BAG3 promotes anti-apoptotic activity by interfering with protein chaperones and release of cytochrome-c. We are also examining effects on the entire transcriptome upon treatment with laromustine using GeneChip Microarrays. Finally, we have created a stable BAG3 knockdown cell line using an shRNA construct via lentiviral transfection. Substantial differences in laromustine-induced cytotoxicity in differing BAG3 backgrounds would suggest a mechanistic role in a cell's defense against laromustine and possibly an improved clinical approach.

Citation Format: Kevin P. Rice, Amanda J. Loya, Kayla M. Gross. The role of BAG3 in human leukemia cells’ response to the experimental anticancer drug laromustine. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4777.
Abstract 4784: FGFR-selective inhibitor Debio 1347 induces tumor regressions in FGFR2-altered gastric cancer PDX models
Authors: Franck Brichory , Pokorska-Bocci Anna , Nuciforo Paolo , Rigotti Stefania , Lembrez Nathalie , Vuagniaux Grégoire , Moulon Corinne , Vaslin Anne
Published: July 2016

Dysregulation of the fibroblast growth factor receptor (FGFR) signaling pathway due to receptor overexpression, gene amplification, point mutations or fusions/chromosomal translocations is associated with cancer development and progression. In gastric cancer, alterations of FGFR2 are observed in a subset of patients, overexpression being more frequently observed as compared to FGFR2 amplifications. In addition, FGFR2 amplification and ERBB2, EGFR, MET and KRAS amplifications are mutually exclusive suggesting that FGFR targeted therapy would be most effective in the FGFR2-amplified subgroup of patients. Debio 1347 (CH5183284) is an oral selective FGFR inhibitor currently in clinical development. The aim of the study was to investigate the preclinical activity of Debio 1347 in patient derived xenograft (PDX) mouse models harboring diverse FGFR alterations in multiple indications, including gastric cancer.

The mouse trial was conducted in 39 different PDX models selected according to FGFR1, 2 and 3 alterations status. Debio 1347 was administered orally once daily and tumor volume was monitored for 14 consecutive days. PDX tumors were extensively characterized using FISH, RNAseq, nCounter Gene Expression and immunohistochemistry (IHC), and FGFR molecular alterations were correlated with Debio 1347 efficacy. The level of tumor heterogeneity for FGFR2 amplification and expression and its impact on drug response were also assessed.

In gastric cancer, Debio 1347 induced tumor regression in models harboring the commonly found FGFR2 amplification. Interestingly, Debio 1347 was also highly effective in models with high FGFR2 expression but without FGFR2 amplification, indicating that not only gene amplification drives the activity of Debio 1347 in this indication, but also the expression level of FGFR2.

Altogether, these data demonstrate that Debio 1347 could be highly effective in gastric cancer patients harboring FGFR2 amplification and/or high FGFR2 expression. Debio 1347 is currently investigated in a Phase I trial in selected patients harboring FGFR alterations (NCT01948297).

Citation Format: Brichory Franck, Anna Pokorska-Bocci, Paolo Nuciforo, Stefania Rigotti, Nathalie Lembrez, Grégoire Vuagniaux, Corinne Moulon, Anne Vaslin. FGFR-selective inhibitor Debio 1347 induces tumor regressions in FGFR2-altered gastric cancer PDX models. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4784.
Abstract 4806: Enhancing the efficacy of tosedostat through carboxylesterase induction
Authors: Hong Priscilla Wei Ling , Smith Amanda Melanie , Johnson Lambro Angelo , Loo Dorothy , Stoll Thomas , Hill Michelle M. , Moore Andrew S.
Published: July 2016

Malignant cells, including acute myeloid leukaemia (AML), have high protein turnover to support their accelerated cell growth. Aminopeptidases regulate proteolysis, supplying free amino acids for new protein synthesis. Inhibition of aminopeptidases depletes free amino acids, impairing new protein production, leading to impaired cell growth and proliferation. Hence, aminopeptidase inhibition is of particular interest as a therapeutic strategy for AML. Tosedostat (CHR-2797) is an aminopeptidase inhibitor which is converted to its active metabolite, CHR-79888, by intracellular carboxylesterases (CES). This active metabolite is poorly membrane permeable, resulting in intracellular accumulation. Tosedostat has shown promise as a potential therapeutic strategy for AML and is well-tolerated in adult patients. However, its efficacy in paediatric AML has not been established. We set out to investigate the use of tosedostat for paediatric AML and enhance its efficacy through CES1 induction. It is hypothesised that inducing CES will lead to increased CHR-79888 production and subsequently, increased tosedostat efficacy. The IC50 of tosedostat across 11 AML cell lines (6 paediatric and 5 adult), determined by resazurin reduction assay, was approximately 13μM. Biochemical assays demonstrated that tosedostat inhibited cellular aminopeptidase activity in a concentration-dependent manner. However, this inhibitory effect was reversible with rapid, but incomplete, enzyme activity recovery upon drug withdrawal, irrespective of initial concentration or treatment duration. Quantitative PCR and immunoblotting revealed no correlation between CES expression and sensitivity to tosedostat. Cellular CES1 activity was also measured. Benzil and Bis(4-nitrophenyl)phosphate (BNPP) were used to modulate cellular CES1 activity. Assays of CES1 enzyme kinetics demonstrated that following temporary exposure to the reversible CES inhibitor benzil, there is a rebound in CES1 activity in AML cells. Consistent with this observation, pre-treatment by benzil increased CES1 activity, especially in MV4-11 cells. Moreover, reduced cell viability with tosedostat treatment following benzil pre-treatment correlated with the induction of CES1 activity in AML cell lines. Together, these data suggest that enhanced tosedostat efficacy through induction of CES activity is a novel therapeutic approach to treat AML.

Citation Format: Priscilla Wei Ling Hong, Amanda Melanie Smith, Lambro Angelo Johnson, Dorothy Loo, Thomas Stoll, Michelle M. Hill, Andrew S. Moore. Enhancing the efficacy of tosedostat through carboxylesterase induction. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4806.
Abstract 481: Low-molecular-mass secretome profiling identifies prognostic biomarkers for oral cavity squamous cell carcinomas
Authors: Chang Kai-Ping , Yu Jau-Song
Published: July 2016

The profiling of cancer cell secretomes is considered to be a good strategy for identifying cancer- related biomarkers, but few studies have focused on identifying low-molecular-mass (LMr) proteins (<15 kDa) in cancer cell secretomes. Here, we used tricine-SDS-gel-assisted fractionation and LC-MS/MS to systemically identify LMr proteins in the secretomes of five oral cavity squamous cell carcinoma (OSCC) cell lines. Cross-matching of these results with nine OSCC tissue transcriptome datasets allowed us to identify 33 LMr genes/ proteins that were highly upregulated in OSCC tissues and secreted/released from OSCC cells. Immunohistochemistry and quantitative real-time PCR were used to verify the overexpression of two candidates, HMGA2 and MIF, in OSCC tissues. The overexpressions of both proteins were associated with cervical metastasis, perineural invasion, deeper tumor invasion, higher overall stage, and a poorer prognosis for post-treatment survival. Functional assays further revealed that both proteins promoted the migration and invasion of OSCC cell lines in vitro. Collectively, our data indicate that the tricine-SDS-gel/LC-MS/MS approach can be used to efficiently identify LMr proteins from OSCC cell secretomes, and suggest that HMGA2 and MIF could be potential tissue biomarkers for OSCC.

Citation Format: Kai-Ping Chang, Jau-Song Yu. Low-molecular-mass secretome profiling identifies prognostic biomarkers for oral cavity squamous cell carcinomas. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 481.