Discovery of Prostate Cancer Tumor Suppressors and Mediators of MDV3100 Resistance Through in Vivo RNA Interference Screen

We set out to identify factors that mediate resistance to enzalutamide therapy using a customized shRNA screen in in vivo mice models. During the reporting time 8 months, we had collected and made pools of the required shRNA, mostly of genes that are recurrently deleted in prostate cancer. However, testing of complexity screens using empty vector with random sequences showed that 50 the xenografted tumors to be made of only a few hairpins. The stochastic nature of distribution of cells forming the tumor would confound findings at later stages when we have actual hairpins.Thus, in vitro FACS-based screen was setup to identify factors that lead to formation of NEPC during prolonged enzalutamide treatment. This was carried out in collaboration with Dr. Mark Rubin and Dr. Himisha Beltran at Weill Cornell Medical Center.We were able to devise a construct that would fluoresce as the cell converted towards the NEPC phenotype using a Neuron Specific enolase promoter driven GFP. During my move, we were able to isolate cells in various stages of neuroendocrine differentiation.