Abstract 5069: p66Shc regulates the migration of castration-resistant prostate cancer

Abstract

Abstract Purpose and Background: Prostate cancer (PCa) remains the most commonly diagnosed solid tumor and is the second leading cause of cancer-related death in United States men. While androgen deprivation therapy is the current standard-of-care treatment for metastatic PCa, most patients eventually relapse and develop castration-resistant (CR) tumors for which there is currently no effective treatment. p66Shc, a 66 kDa Src and collagen homologue oxidase, is elevated in clinical PCa as well as multiple PCa cell lines which correspond with advanced CR PCa. Additionally, p66Shc has been demonstrated to promote proliferation in PCa cell lines via generation of reactive oxygen species (ROS). This study is the first to demonstrate p66Shc also regulates PCa cell migration. Understanding of the mechanism through which p66Shc promotes migration may lead to the development of therapeutic strategies to treat metastatic CR PCa. Experimental Methods: Human prostate adenocarcinoma cell lines LNCaP C-33 and C-81, androgen-sensitive (AS) and androgen independent (AI) MDA PCa2b, PC-3, and DU145 were used to determine the role of p66Shc in PCa migration. Stable p66Shc cDNA transfected subclones S-31, S-32, and S-36 were established from LNCaP C-33 cells. p66Shc's impact on migration was determined using transwell migration assays. Immunoblotting was performed to profile potential proteins involved in the mechanism through which p66Shc influences migration. Small-molecule inhibitors were used to confirm these proteins’ involvement in migration. Results: Levels of p66Shc protein positively correlate with metastatic potential across multiple PCa cell lines as well as LNCaP and MDA call progressive models. p66Shc is an authentic oxidase and promotes ROS production. In this study, we further demonstrate peroxide treatment is able to induce C-33 cell migration in a dose-dependent manner, while antioxidants inhibit migration. Similarly, p66Shc subclones possess increased migratory ability which is abolished upon antioxidant treatment and demonstrates the involvement of ROS in p66Shc-mediated migration. Molecular profiling reveals the correlation of p66Shc protein level with the activation of ErbB-2, PYK2, AKT, ERK, p38, RAC1, STAT3, and STAT5 as well as suppression of cPAcP. Conclusions: Altogether, our results indicate p66Shc is involved in PCa cell migration, in part, by inducing ROS generation. Understanding the role p66Shc in advanced PCa progression will help to determine its potential as a therapeutic target, and elucidating its mechanism of intracellular signaling will enable us to design new treatments for metastatic CR PCa. Citation Format: Matthew A. Ingersoll, Sakthivel Muniyan, Fen-Fen Lin, Ta-Chun Yuan, Yu-Wei Chou, Surinder K. Batra, Ming-Fong Lin. p66Shc regulates the migration of castration-resistant 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 5069.