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// Yixuan Gong 1, * , Li Wang 2, 3, * , Uma Chippada-Venkata 1 , Xudong Dai 2, 3 , William K. Oh 1 , Jun Zhu 1, 2, 3 1 The Tisch Cancer Institute, Division of Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, USA 2 Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA 3 Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA * These authors have contributed equally to this work Correspondence to: Jun Zhu, email: jun.zhu@mssm.edu William K. Oh, email: William.oh@mssm.edu Keywords: Bayesian networks, NLGN4Y, prostate cancer, negative regulator, gene expression Received: April 15, 2016 Accepted: August 24, 2016 Published: September 10, 2016 ABSTRACT To understand the heterogeneity of prostate cancer (PCa) and identify novel underlying drivers, we constructed integrative molecular Bayesian networks (IMBNs) for PCa by integrating gene expression and copy number alteration data from published datasets. After demonstrating such IMBNs with superior network accuracy, we identified multiple sub-networks within IMBNs related to biochemical recurrence (BCR) of PCa and inferred the corresponding key drivers. The key drivers regulated a set of common effectors including genes preferentially expressed in neuronal cells. NLGN4Y—a protein involved in synaptic adhesion in neurons—was ranked as the top gene closely linked to key drivers of myogenesis subnetworks. Lower expression of NLGN4Y was associated with higher grade PCa and an increased risk of BCR. We show that restoration of the protein expression of NLGN4Y in PC-3 cells leads to decreased cell proliferation, migration and inflammatory cytokine expression. Our results suggest that NLGN4Y is an important negative regulator in prostate cancer progression. More importantly, it highlights the value of IMBNs in generating biologically and clinically relevant hypotheses about prostate cancer that can be validated by independent studies.

// Ying Gao 1 , Renbin Huang 2 , Yixuan Gong 3 , Hyo Sim Park 1 , Qingwei Wen 2 , Nadin Marwan Almosnid 1 , Uma D. Chippada-Venkata 3 , Najlaa Abdulrhman Hosain 1 , Eric Vick 1 , Anthony Farone 1 and Elliot Altman 1 1 Tennessee Center for Botanical Medicine Research and the Department of Biology, Middle Tennessee State University, Murfreesboro, Tennessee, USA 2 Pharmaceutical College, Guangxi Medical University, Nanning, Guangxi, PR China 3 Division of Hematology and Medical Oncology, The Tisch Cancer Institute, Mount Sinai School of Medicine, New York, New York, USA Correspondence to: Ying Gao, email: // Keywords : antitumor, apoptosis, cell cycle, reactive oxygen species, NF-κB Received : April 10, 2015 Accepted : May 31, 2015 Published : June 15, 2015 Abstract 2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) is a cyclohexanedione found in the roots of Averrhoa carambola L . , commonly known as starfruit. Researchers have shown that DMDD has significant therapeutic potential for the treatment of diabetes; however, the effects of DMDD on human cancers have never been reported. We investigated the cytotoxic effects of DMDD against human breast, lung and bone cancer cells in vitro and further examined the molecular mechanisms of DMDD-induced apoptosis in human breast cancer cells. DMDD suppressed the growth of breast carcinoma cells, but not normal mammary epithelial cells, via induction of G1 phase cell cycle arrest, oxidative stress and apoptosis. DMDD increased the level of intracellular reactive oxygen species (ROS) and DMDD-induced ROS generation was found to be associated with the mitochondrial activity. The cytotoxicity that was induced by DMDD was attenuated by co-treatment with the antioxidant N-acetyl-L-cysteine (NAC). DMDD-induced cell apoptosis involved the activation of both the intrinsic mitochondrial pathway and the extrinsic receptor pathway. In addition, DMDD inhibited the canonical NF-κB signaling pathway at all steps, including TNF-α production, phosphorylation of NF-κB p65 and IκBα, as well as TNF-α activated NF-κB p65 nuclear translocation.Collectively, our studies indicate that DMDD has significant potential as a safe and efficient therapeutic agent for the treatment of breast cancer.

BACKGROUND. Tissue inhibitor of metalloproteinase-1 (TIMP-1) is a 28.5kDa secreted glycoprotein that inhibits matrix metalloproteinase (MMP) activity. Our group has previously shown that elevated plasma TIMP-1 levels predict poor survival in metastatic castrationresistant prostate cancer (CRPC) patients; however, the underlying source and impact of elevated circulating TIMP-1 protein is unknown. METHODS. In this study, we used qRT-PCR, ELISA and immunohistochemistry to evaluate TIMP-1 expression in androgen-sensitive and resistant prostate cancer (PC) cell lines, tumor tissues and patient sera, and to correlate TIMP-1 levels to expression of chromogranin A (CGA), an established marker of neuroendocrine differentiation (NED). We also explored the relationship between TIMP-1 overexpression and induction of NED by overexpressing TIMP-1 in androgen-sensitive LNCaP cells, as well as by inducing NED of LNCaP cells with IL-6. RESULTS. Patients with CRPC have significantly higher serum TIMP-1 levels compared to patients with hormone-sensitive disease. Although circulating TIMP-1 levels were increased, peripheral blood cells were not the source of elevation. Instead, elevated TIMP-1 expression was associated with higher expression of CGA in both blood and metastatic tumor tissue. We further show that androgen receptor (AR) and PSA non-expressing prostate cancer cell lines known to display NED phenotypes such as PC-3, PC-3M, and DU145 cells, expressed high levels of TIMP-1, in contrast to AR (þ) and PSA (þ) adenocarcinoma cell lines such as LNCaP, VCaP, and LAPC-4, which had barely detectable levels of TIMP-1. In addition, ectopic overexpression of TIMP-1 in LNCaP cells did not induce NED. However, TIMP-1 mRNA expression was elevated >10-fold during IL-6-induced NED of LNCaP cells, suggesting that TIMP-1 overexpression accompanies, but is not the driving force for NED. Finally, we show that conditioned media from androgen-resistant PC-3, PC-3M, and DU145 cells induced TIMP-1 mRNA expression in primary prostate stromal fibroblasts in an ERK and NF-kB dependent manner. CONCLUSIONS. We provide in vitro and clinical evidence to support the association between NED and elevated circulating TIMP-1 expression in CRPC. Our observation

Matrix metalloproteinases (MMPs), a group of zinc-dependent endopeptidases involved in the degradation of the extracellular matrix, play an important role in tissue remodeling associated with various physiological processes such as morphogenesis, angiogenesis, and tissue repair, as well as pathological processes including cirrhosis, arthritis and cancer. The MMPs are well established as mediators of tumor invasion and metastasis by breaking down connective tissue barriers. Although there has been a vast amount of literature on the role of MMPs in invasion, metastasis and angiogenesis of various cancers, the role of these endopeptidases in prostate cancer progression has not been systematically reviewed. This overview summarizes findings on the tissue and blood expression of MMPs, their function, regulation and prognostic implication in human prostate cancer, with a focus on MMP-2, -7, -9, MT1-MMP and tissue inhibitor of metalloproteinase 1 (TIMP-1). This review also summarizes the efficacy and failure of early-generation matrix metalloproteinase inhibitors (MMPIs) in the treatment of metastatic prostate cancer and highlights the lessons and challenges for next generation MMPIs.

Patient derived xenograft (PDX) models are gaining popularity in cancer research and are used for preclinical drug evaluation, biomarker identification, biologic studies, and personalized medicine strategies. Circulating tumor cells (CTC) play a critical role in tumor metastasis and have been isolated from patients with several tumor types. Recently, CTCs have been used to generate PDX experimental models of breast and prostate cancer. This manuscript details the method for the generation of prostate cancer PDX models from CTCs developed by our group. Advantages of this method over conventional PDX models include independence from surgical sample collection and generating experimental models at various disease stages. Density gradient centrifugation followed by red blood cell lysis and flow cytometry depletion of CD45 positive mononuclear cells is used to enrich CTCs from peripheral blood samples collected from patients with metastatic disease. The CTCs are then injected into immunocompromised mice; subsequently generated xenografts can be used for functional studies or harvested for molecular characterization. The primary limitation of this method is the negative selection method used for CTC enrichment. Despite this limitation, the generation of PDX models from CTCs provides a novel experimental model to be applied to prostate cancer research.

Castration-resistant prostate cancer (CRPC) is associated with wide variations in survival. Recent studies of whole blood mRNA expression-based biomarkers strongly predicted survival but the genes used in these biomarker models were non-overlapping and their relationship was unknown. We developed a biomarker model for CRPC that is robust, but also captures underlying biological processes that drive prostate cancer lethality. Using three independent cohorts of CRPC patients, we developed an integrative genomic approach for understanding the biological processes underlying genes associated with cancer progression, constructed a novel four-gene model that captured these changes, and compared the performance of the new model with existing gene models and other clinical parameters. Our analysis revealed striking patterns of myeloid- and lymphoid-specific distribution of genes that were differentially expressed in whole blood mRNA profiles: up-regulated genes in patients with worse survival were overexpressed in myeloid cells, whereas down-regulated genes were noted in lymphocytes. A resulting novel four-gene model showed significant prognostic power independent of known clinical predictors in two independent datasets totaling 90 patients with CRPC, and was superior to the two existing gene models. Whole blood mRNA profiling provides clinically relevant information in patients with CRPC. Integrative genomic analysis revealed patterns of differential mRNA expression with changes in gene expression in immune cell components which robustly predicted the survival of CRPC patients. The next step would be validation in a cohort of suitable size to quantify the prognostic improvement by the gene score upon the standard set of clinical parameters. The project was partially funded by Young Investigator Award from Prostate Cancer Foundation (LW), R01MH090948 (JZ), and U01AG046170 (JZ). None of the aforementioned funding bodies were involved in the study design and conduct. We would like to thank our team of clinical coordinators including Teena Kochukoshy, Manpreet Brar, and Victoria Gresia for consenting patients, collecting blood, and providing database support for the study. JDB's laboratory is supported by a Cancer Research UK Centre grant, Experimental Cancer Medicine Centre funding, a Prostate Cancer UK and Movember Centre of Excellence grant, and a National Institute for Health Research Biomedical Research Center to the Royal Marsden/ICR. Sí

Meeting abstracts Metastatic bladder cancer (MBC) is a relatively chemosensitive neoplasm yet response durations are generally short-lived. Recently, immune checkpoint blockade has demonstrated unparalleled activity in heavily pre-treated patients (pts) with MBC. The role of standard chemotherapy

4586 Background: Immune checkpoint blockade may play a role in the treatment of mUC. However, the role of CTLA4 blockade, the impact of chemotherapy on immune cell populations, and the optimal appr...

166 Background: Prostate cancer is a heterogeneous disease with differences in tumor stromal interactions contributing to variability in treatment response and outcome. Gene expression of peripheral blood cells is altered by interactions with neoplastic tissue. We previously developed a peripheral whole blood six-gene signature prognostic for survival in mCRPC. Here we evaluate how different clinical disease states and treatment with different therapeutic agents impact this signature. Methods: Whole blood was collected in PAXgene Blood RNA tubes in two cohorts of prostate cancer patients, one at Mount Sinai (n=135), the other in Munich (n=59), in the context of prospective clinical studies. Whole blood RNA was extracted and the six target genes were amplified using qPCR. Scores were derived using normalized cycle threshold (ΔCT) values of the six genes, according to the model: 2 x ABL2 + SEMA4D + ITGAL – C1QA – TIMP1 – CDKN1A. Patients were categorized by disease state in the Mount Sinai cohort, and by treatment received in the Munich cohort, for data analysis. Results: CRPC is the only disease state with a mean six-gene score (18.06) above the high-risk cutoff (17.9), and is significantly higher than localized or hormone sensitive advanced disease (16.07, 16.52, respectively; p=0.0002). Among patients with localized disease, there was no significant difference in the mean six-gene scores for patients with low-, intermediate-, and high-risk disease (16.07, 15.33, 16.66, respectively; p=0.27). In CRPC patients treated with docetaxel, there are significant changes to the six-gene score over the course of treatment (p=0.002), with a notable percentage decrease (-6.2%) at the 2-8 week timepoint that is not observed in patients treated with abiraterone or enzalutamide. Conclusions: Gene expression profiling of whole blood is influenced by the clinical state of prostate cancer as seen by differences to the six-gene score from localized to castrate resistant disease. Cytotoxic chemotherapy appears to modulate the six-gene score, something not seen with AR-directed therapies. Further investigation will be needed to understand the significance of these changes.

BACKGROUND: Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a 28.5 kDa secreted glycoprotein that inhibits matrix metalloproteinase (MMP) activity. Recent studies have demonstrated that TIMP-1 promotes tumor growth in an MMP-independent manner. We have previously shown that elevated plasma TIMP-1 predicts worse survival in mCRPC patients; however, the mechanism underpinning this association is unknown. Normal and malignant neuroendocrine (NE) cells, from various organs, express TIMP-1 as measured by immunohistochemistry (IHC). We hypothesized that elevated blood levels of TIMP-1 in mCRPC patients results from androgen deprivation therapy-induced NE differentiation. METHODS: In this study, we used qPCR, ELISA and IHC to correlate the expression of TIMP-1 and NE markers such as chromogranin A (CGA) in 7 prostate cancer cell lines, 37 patient serum samples and prostate cancer (adenocarcinoma and NE cancer) tissue microarrays. RESULTS: We first examined TIMP-1 and NE marker (NSE and PTHLH) mRNA expression in 7 prostate cancer cell lines. Our results show that PC-3, PC-3M, DU145 cells express high levels of TIMP-1 as well as NE markers. On the other hand, LNCAP, VCAP and LAPC-4 cells had barely detectable levels of TIMP-1 and much lower expression of NE markers. We then measured serum TIMP-1 and CGA levels from CRPC patient samples by ELISA. Patients with castration resistant disease had significantly higher serum TIMP-1 levels (mean value of 373.5 ng/ml) than patients with hormone sensitive disease (mean value of 304.8 ng/ml) (p=0.01), suggesting that castration resistance in prostate cancer patients is associated with increased TIMP-1 production. Interestingly, when we divided patients using a cutoff of 100 ng/ml (based on cutoffs reported in published literature), serum TIMP-1 was significantly higher in the high CGA group (p=0.018), indicating an association between TIMP-1 production and existing NE markers. We also compared PSA values between low and high CGA groups and found that the high CGA group was associated with lower PSA levels (p=0.029). Next, we explored TIMP-1 expression in NE tumor tissues. We performed TIMP-1 and CGA IHC staining in archival liver neuroendocrine and thyroid cancers and found that TIMP-1 expression was associated with CGA expression. In prostate cancer specimens, normal prostate epithelial cells expressed high levels of TIMP-1, but the expression was lost in adenocarcinomas. In contrast, prostatic neuroendocrine cancers expressed high levels of TIMP-1 as well as the NE marker CGA. CONCLUSIONS: These observations support the further evaluation of TIMP-1 as a tissue and serum biomarker for NE differentiation in CRPC. Note: This abstract was not presented at the meeting. Citation Format: Yixuan Gong, Uma Chippada-Venkata, Xudong Dai, Matthew D. Galsky, Jiaoti Huang. TIMP-1: A potential biomarker of neuroendocrine differentiation in metastatic castration-resistant prostate cancer (mCRPC). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1098. doi:10.1158/1538-7445.AM2014-1098

36 Background: We developed a whole-blood RNA transcript-based six gene signature (ABL2, SEMA4D, ITGAL, C1QA, TIMP1, CDKN1A), which separates patients with metastatic castration-resistant prostate cancer (mCRPC) into high- and low-risk survival groups (Ross et al. Lancet Oncology, 2012). In this study, the prognostic utility of the signature is validated on two independent platforms: an updated qPCR platform and an RNA-sequence platform in a new cohort of patients. The dynamic changes in the gene expression are examined during disease progression in serial samples from individual patients. Methods: Whole blood RNA was extracted from PAXgene tubes drawn from 63 patients with prostate cancer representing a range of clinical disease states. Serial samples were collected from a subset of patients (n=34). Survival prediction scores were derived independently based on the RNA-transcript levels of the six genes as quantified by a new ViiA 7 qPCR platform and by Illumina RNA-sequence. Results: The six gene signature scores generated on both qPCR and RNA-sequence platforms remain highly prognostic, separating mCRPC patients into high- and low-risk survival groups (logrank test; p-value for qPCR