Citations

Abstract Aims: Androgen-targeted therapies (ATTs) are the mainstay treatment for metastatic prostate cancer (PCa). However, ATTs promote adaptation of tumour cells and lead to castration resistant disease (CRPC). We have recently identified the cell surface receptor, Neuropilin-1 (NRP1) as increased during EMT and in CRPC. However, the role of NRP1 in the prostate epithelium is poorly understood. This study aims to determine whether the inhibition of NRP1 will be a feasible therapeutic strategy for blocking PCa metastasis and therapy resistance. Methods: qPCR and western blotting were used to assess NRP1 expression in PCa cell lines. NRP1 expression in CRPC was assessed using a murine LNCaP xenograft model of castration. NRP1 was knocked down with shRNA sequences from the pLKO.1 lentiviral construct. For metastasis assays, PC3 cells were microinjected into the zebrafish yolk sac and metastatic dissemination imaged 5 days later. NRP1 expression in radical prostatectomy (RP) samples from Mayo Clinic (545 patients) and Johns Hopkins Medical Institutions (JHMI; 188 patients) cohorts was quantified by Affymetrix exon arrays and multivariable analysis performed. Wound scratch migration and invasion assays were performed with the WoundMaker™ tool and IncuCyte™ FLR imaging systems. Results: NRP1 levels were elevated in humanCRPC xenografts, metastatic and castrate resistant clinical PCa samples (p <0.0001), and PCa cell lines. NRP1 suppression significantly reduced metastasis of human xenografts in zebrafish and the migratory and invasive behaviour of metastatic PCa cells (p=0.0002). Multivariable analysis identified NRP1 as a significant independent prognostic indicator of metastasis and prostate cancer specific mortality in two large clinical cohorts (Mayo Clinic and JHMI; p=0.008/0.048 and 0.013/0,034 respectively). We show that NRP1 knockdown promotes E-Cadherin expression and loss of vimentin in mesenchymal PCa cells. Conclusion: These results will provide the preclinical data necessary to rationalise the use of anti-NRP1 directed adjuvant therapies for clinical use in PCa patients receiving ATTs, and will pave the way for larger scale preclinical and clinical trials in the PCa setting. Citation Format: Marianna Volpert, Brian Tse, Ellca Ratther, Nataly Stylianou, Mannan Nouri, Melanie Lehman, Stephen McPherson, Mani Roshan-Moniri, Mandeep Takhar, Nicholas Erho, Mohamed Alshalafa, Elai Davicioni, Robert Jenkins, Ashley Ross, Jeffrey Karnes, Robert Den, Ladan Fazli, Martin Gleave, Elizabeth Williams, Paul Rennie, Ralph Buttyan, Pamela Russell, Colleen Nelson, Brett Hollier. Neuropilin-1 is up-regulated in the adaptive response of prostate tumors to androgen targeted therapies and is prognostic of metastatic progression and patient mortality [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4908. doi:10.1158/1538-7445.AM2017-4908

256 Background: B7-H3 (CD276), part of the B7 superfamily, has been shown to play an immunomodulatory role, however its regulation, receptor and mechanism of action remain unclear. Protein levels of B7-H3 have been previously shown to relate to prostate cancer outcomes and currently, humanized monoclonal antibodies are being developed for clinical use (MGA271, Macrogenics). Here we use genomic expression data to examine the relationship of B7-H3 to prostate cancer outcomes and molecular subtypes. Methods: Prostatectomy tissue from 905 patients were profiled using the Affymetrix HuEx 1.0 ST microarray. Kruskal-Wallis tests were used to identify significant associations of B7-H3 expression with clinico-pathologic variables, and survival analysis were used to evaluate the prognostic value of B7-H3. Pearson’s correlation analyses were also performed to assess the relationship of B7-H3 expression with molecular subtypes and individual transcripts. Androgen receptor (AR) occupancy of promoter regions was derived in silico from chromosomal immune-precipitation (ChIP) data. Results: B7-H3 expression was positively associated with Gleason score (p < 0.01) and tumor stage (p < 0.01). High B7-H3 expression also correlated with the development of metastasis and prostate cancer specific mortality (HR of 3.4 and 2.4 respectively, p < 0.05 for both), but this was not significant on multi-variable analysis. B7-H3 was positively associated with ERG+ disease (n = 670, r = 0.85, p < 0.05) and AR expression (n = 670, r = 0.46, p < 0.001). B7-H3 was found to be one of the most correlated genes with AR (95th percentile) and ChIP analysis revealed AR binding upstream of B7-H3, suggesting potential androgen dependent regulation. Conclusions: B7-H3 expression correlates with high Gleason grade and advanced prostate cancer stage with higher quartiles of expression portending poor oncologic outcomes in two independent prostatectomy cohorts. B7-H3 expression appears to relate to the androgen receptor.

Objectives To determine the prognostic potential of a 24‐gene signature, Sig24, for identifying patients with prostate cancer who are at risk of developing metastases or of prostate cancer‐specific mortality (PCSM) after radical prostatectomy (RP). Patients and Methods Sig24 scores were calculated from previously collected gene expression microarray data from the Cleveland Clinic and Mayo Clinic (I and II). The performance of Sig24 was determined using time‐dependent c‐index analysis, Cox proportional hazards regression and Kaplan–Meier survival analysis. Results Higher Sig24 scores were significantly associated with higher pathological Gleason scores in all three cohorts. Analysis of the Mayo Clinic II cohort, which included time‐to‐event information, indicated that patients with high Sig24 scores also had a higher risk of developing metastasis (hazard ratio [HR] 3.78, 95% confidence interval [CI]: 1.96–7.29; P < 0.001) or of PCSM (HR 6.54, 95% CI: 2.16–19.83; P < 0.001). Conclusions The findings of the present study show the applicability of Sig24 for the prognosis of metastasis or PCSM after RP. Future studies investigating the combination of Sig24 with available prognostic tests may provide new approaches to improve risk stratification for patients with prostate cancer.

Abstract In the era of precision medicine, genomic classifications of prostate cancer (PC) have not broadly impacted patient care. Here we present an integrative transcriptome analysis of 14 disease-related pathways in over 4,600 clinical specimens and 25 PC preclinical models. This approach provides a novel classification scheme, inclusive of 3 PC subtypes (PCS1-3), which predict disease progression and drug resistance. The PCS1 and PCS2 categories possess characteristics of luminal cells, while PCS3 exhibits basal features. Castration-resistant and metastatic cancers are over-represented in PCS1 and PCS3 tumors. All 3 subtypes are represented in commonly used PC cell lines; however, none of the mouse models we analyzed resembles PCS3. PCS classification using RNA expression data appears to be stable across primary and metastatic human tumors, cell lines, xenografts and mouse models. This new subtyping method provides novel opportunities for patient stratification that reflect specific features of tumor biology and may influence therapeutic decisions. Citation Format: Sungyong You, Beatrice Knudsen, Nicholas Erho, Mohammed Alshalalfa, Mandeep Takhar, Hussam Al-deen Ashab, Elai Davicioni, Robert Jeffrey Karnes, Eric A. Klein, Robert B. Den, Ashley E. Ross, Edward M. Schaeffer, Isla P. Garraway, Jayoung Kim, Michael R. Freeman. Three intrinsic subtypes of prostate cancer with distinct pathway activation profiles differ in prognosis and treatment response. [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 1502.

Abstract Prostate cancer is a biologically heterogeneous disease with variable molecular alterations underlying cancer initiation and progression. Despite recent advances in understanding prostate cancer heterogeneity, better methods for classification of prostate cancer are still needed to improve prognostic accuracy and therapeutic outcomes. In this study, we computationally assembled a large virtual cohort (n = 1,321) of human prostate cancer transcriptome profiles from 38 distinct cohorts and, using pathway activation signatures of known relevance to prostate cancer, developed a novel classification system consisting of three distinct subtypes (named PCS1–3). We validated this subtyping scheme in 10 independent patient cohorts and 19 laboratory models of prostate cancer, including cell lines and genetically engineered mouse models. Analysis of subtype-specific gene expression patterns in independent datasets derived from luminal and basal cell models provides evidence that PCS1 and PCS2 tumors reflect luminal subtypes, while PCS3 represents a basal subtype. We show that PCS1 tumors progress more rapidly to metastatic disease in comparison with PCS2 or PCS3, including PSC1 tumors of low Gleason grade. To apply this finding clinically, we developed a 37-gene panel that accurately assigns individual tumors to one of the three PCS subtypes. This panel was also applied to circulating tumor cells (CTC) and provided evidence that PCS1 CTCs may reflect enzalutamide resistance. In summary, PCS subtyping may improve accuracy in predicting the likelihood of clinical progression and permit treatment stratification at early and late disease stages. Cancer Res; 76(17); 4948–58. ©2016 AACR.

Abstract Emerging evidence demonstrates that the DNA repair kinase DNA-PK exerts divergent roles in transcriptional regulation of unsolved consequence. Here, in vitro and in vivo interrogation demonstrate that DNA-PK functions as a selective modulator of transcriptional networks that induce cell migration, invasion, and metastasis. Accordingly, suppression of DNA-PK inhibits tumor metastases. Clinical assessment revealed that DNA-PK is significantly elevated in advanced disease, and independently predicts for metastases, recurrence, and reduced overall survival. Further investigation demonstrated that DNA-PK in advanced tumors is highly activated, independently of DNA damage indicators. Combined, these findings put forth new paradigms for DNA-PK function, identify DNA-PK as a potent driver of tumor progression and metastases, and nominate DNA-PK as a therapeutic target for advanced malignancies. Citation Format: Jonathan F. Goodwin, Vishal Kothari, Justin M. Drake, Shuang Zhao, Emanuela Dylgjeri, Jeffry L. Dean, Matthew J. Schiewer, Christopher McNair, Michael S. Magee, Robert B. Den, Ziqi Zhu, Nicholas A. Graham, Ajay A. Vashisht, James A. Wohlschlegel, Thomas G. Graeber, R Jeffrey Karnes, Mandeep Takhar, Elai Davicioni, Scott A. Tomlins, Nima Sharifi, Owen N. Witte, Felix Y. Feng, Karen E. Knudsen. DNA-PK-mediated transcriptional regulation drives tumor progression and metastasis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1860. doi:10.1158/1538-7445.AM2015-1860