Abstract 4285: p66Shc/ROS enhances the progression of androgen-sensitive towards castration-resistant prostate cancer cells

Purpose and Background: Prostate cancer (PCa) is the second leading cause of cancer-related death in United States men. Androgen deprivation therapy is the standard-of-care treatment for metastatic PCa; most patients eventually relapse and develop castration-resistant (CR) tumors that currently have no effective treatment. Thus, a useful cell model for analysis of the molecular mechanism of PCa progression is required for developing targeted therapies for CR PCa. In this study, we established a PCa cell progressive model in three independent cell lines, of which androgen-independent (AI) cells were derived from respective androgen-sensitive (AS) cells, recapitulating clinical PCa progression. Experimental Methods: AS and AI human prostate adenocarcinoma cell lines LNCaP, MDA PCa2b and VCaP were utilized in this study to demonstrate the molecular and signaling alterations seen in CR PCa. Stable p66Shc cDNA transfected subclones were established from LNCaP-AS cells. The tumorigenicity of AS and AI cells as well as AS PCa cells treated with H2O2 and NAC were evaluated via trypan blue exclusion, transwell migration, clonogenic assays and xenograft mouse models. The signaling profiles including phosphoprotein microarray and immunoblotting were conducted. Results: AI PCa cells have enhanced tumorigenicity, recapitulating the clinical CR phenotype, including AR expression, proliferation and tumorigenicity under androgen-deprived conditions. Further, AI cells exhibit increased ROS levels as well as enhanced signaling of proliferation and survival pathways. We further identified oxidase p66Shc as one of the potential sources of the ROS-mediated phenotypic and cell signaling alterations in AI PCa cells. LNCaP-AI cells and p66Shc subclones have a greater oxidative environment compared to LNCaP-AS cells. Increased ROS via H2O2 enhanced AS cell growth and migration, which was counteracted by antioxidant NAC. Treatment of LNCaP-AS cells with H2O2 resulted in a similar signaling profile to that of LNCaP-AI or p66Shc subclone cells. Further, the ROS-driven alterations of p66Shc subclone cell signaling can be mitigated via p66Shc knockdown or inactive p66Shc mutant. Moreover, LNCaP-AI cells and p66Shc subclones, but not LNCaP-AS cells, develop xenograft tumors with metastatic nodules. Molecular profiling showed that alterations of signaling in LNCaP-AI cells and p66Shc subclones attributed to p66Shc/ROS. Conclusions: We report the establishment of a PCa cell progression model in three commonly used PCa cell lines that replicates clinical PCa progression from the AS to the AI/CR phenotype. Altogether, the data shows ROS produced by p66Shc promotes PCa tumorigenicity and progression to the CR phenotype. Further characterization of the PCa progressive model will aid in the understanding of advanced PCa progression to help in treatment of this lethal disease. Citation Format: Dannah Miller, Matthew Ingersoll, Arpita Chatterjee, Rebecca Oberley-Deegan, Ming-Fong Lin. p66Shc/ROS enhances the progression of androgen-sensitive towards castration-resistant prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4285.