796 CORTISOL SERUM LEVELS ARE INCREASED AND INDUCE GENOMIC INSTABILITY IN ADVANCED PROSTATE CANCER

Abstract

INTRODUCTION AND OBJECTIVES: Cortisol, also known as stress hormone, is involved with chronic stress; it appears to be associated with higher levels of prostate-specific antigen (PSA) and benign prostate enlargement (BPE). To assess the relationship between cortisol and prostate cancer (PCa), serum cortisol levels were measured in normal men and those with primary or metastatic PCa. In addition, the effect of cortisol on genomic instability was investigated by evaluating DNA mismatch repair (MMR) pathway in androgen-deprived benign or malignant prostate cells. METHODS: Serum cortisol and creatinine levels were determined using ELISA assay. Immunohistochemical staining for MMR proteins was performed on tissue microarray slides. Genomic instability was evaluated by analyzing the microsatellite instability (MSI) using PCR and the National Cancer Institute (NCI)-recommended panel of five MS markers including two mononucleotide repeat (BAT25 and BAT26) and three dinucleotide repeats (D2S123, D5S346, and D17S250). Genomic DNAs for PCR were extracted from AR-positive (LNCaP, E006AA, CWR-22RV1, C4-2B, MDA-PCa2b) and androgeninsensitive (PC-3 and DU145) PCa cell lines and normal prostate epithelial cells that were treated with cortisol and androgen-deprived for 2 to 20 weeks. Purified PCR fragments were separated on ABI 3730XL DNA Analyzer and genotyped using the ABI Gene Mapper ID, V3.2 software. MMR genes and protein expression levels in the cells were examined with qRT-PCR and western blotting, respectively. RESULTS: Serum cortisol levels were in rank order metastatic castrate-resistant prostate cancer (mCRPCa) primary PCa BPE. Serum cortisol levels were higher in African Americans (AAs) than Caucasian Americans (CAs) in BPE, primary PCa, and mCRPCa. Chronic treatment of PCa cells with cortisol increased growth rate and PSA expression. Cortisol induced high-frequency MSI as evidenced by the insertion or deletion of 1-5 bps in at least 2 of 5 MS markers in both androgen-responsive and androgen-insensitive PCa cell lines. Analysis of the DNA mismatch repair pathway in PCa cells and tissues originated from AAs and CAs showed alterations in the expression levels of PMS1, PMS2, MLH1, MSH2, MSH3, MSH6, that belong to the MMR system. CONCLUSIONS: These data support a non-immunological role for cortisol in promoting genomic instability in androgen-deprived PCa cells that might lead to hyper-mutator phenotype or accumulation of adoptive-genetic changes in response to the stress that results from androgen-deprivation therapy for advanced PCa.