Prostate cancer is one of the leading causes of cancer-related death in men worldwide. If diagnosed early, prostate cancer can be treated by surgery and/or radiotherapy. In cases where the cancer has returned or is more aggressive and has metastasized, hormone therapy is the standard treatment. While initially effective, resistance to hormone therapy often occurs. Therefore, there is a pressing demand for new therapeutics to be developed to treat this disease. Previous studies have established that in up to 50% of all prostate cancer cases, a genomic irregularity involving the ETS-related gene (ERG) is present. This alteration results in the aberrant production of predominantly amino-terminal truncated ERG proteins in the prostate where it is linked to disease development and progression. This thesis tested the hypothesis that direct, small molecule targeting of ERG DNA binding could result in inhibition of the metastatic potential of PCa through the following specific aims: a) develop and apply in vitro assays to validate inhibitory activities/mechanisms of lead anti-ERG compounds, and b) determine the therapeutic effects of the lead compounds based on their effects and activity in in vivo xenograft models. The results demonstrate the direct binding of a novel small molecule, VPC-18005, with the ERG-ETS domain using biophysical approaches. This was further supported by reduced migration and invasion rates of ERG expressing prostate cancer cells, and reduced metastasis in a zebrafish xenograft model following exposure to VPC-18005. These results support the concept that small molecules targeting the ERG-ETS domain that suppress transcriptional activity and reverse transformed characteristics of prostate cancers aberrantly expressing ERG can be developed. It is hoped that these approaches might lead to identification of small molecules that can be further developed as drug candidates as alternatives to, or in combination with, current therapies for prostate cancer patients harboring ERG fusions.Medicine, Faculty ofExperimental Medicine, Division ofMedicine, Department ofGraduat
