Our long-term goal is to understand the mechanisms that are responsible for resistance toapoptosis in prostate cancer. Understanding the mechanisms involved in apoptosis in a slowly proliferating cancer such as prostate cancer is critical. The studies proposed focus on TNF-a, which plays a critical role in apoptosis in many different cell types, and are designed to understand the mechanisms of TNF-a-induced apoptosis in human prostate cancer. In preliminary studies, we have investigated the role of p53 and p21, caspases, androgens, NF-kB and mitochondrial involvement in the human prostatic carcinoma cell line LNCaP. Our data, using LNCaP and a p53 dominant negative subline (LN56), indicate that p53 plays an important role in TNF-a-ediated apoptosis. In addition, we have made novel observations about the involvement of bisindolylmalimeide (Bis IX) and will allow us to study the mitochondrial pathway in apoptosis. We believe that we have a fascinating cell system to dissect TNF-a receptor signaling, and which addresses key issues raised in the NCI's recent report on prostate cancer. We hypothesize that p53 plays a critical role in mediating TNF-a-induced apoptosis in human prostate cancer. This hypothesis provides an experimental strategy for the identification of factors that are critical in p53-regulated TNF-a-mediated apoptosis. We will compare signal transduction mechanisms and different components of apoptotic machinery during TNF-a-mediated apoptosis. We believe these findings are generalizable to other cell systems and that other signaling molecules play key roles in TNF-a-mediated cell death. In order to test our hypothesis and identify the mechanisms that are responsible for TNF-a-mediated apoptosis in prostate cancer, we propose the following Specific Aims: 1) Determine the role of p21/WAF1 in TNF-a-mediated apoptosis; 2) Determine the role of caspases in TNF-a-mediated apoptosis; androgen, 3) Determine the role of NF-kB in TNF-a-mediated apoptosis; 4) 4. Determine the role of Bis IX on different TNF-a-related signaling pathways, 5. Determine the applicability to other cell systems and identify new genes involved in TNF-a-mediated apoptosis.
