Anti-proliferation Effect of Polypeptide Extracted from Scorpion Venom on Human Prostate Cancer Cells in vitro

BACKGROUND Prostate cancer is a major cause of cancer-related death in men. Therefore there has been considerable interest to explore neoadjuvant therapy. Polypeptide extracted from scorpion venom (PESV), originally obtained from the East-Asian scorpion Buthus martensi Karsch (BmK), is being studied for both prevention and treatment of various human malignancies including prostate cancer. METHODS The present study was to investigate the effect of PESV on cell proliferation, cell cycle, and apoptosis in human androgen-independent prostate cancer cells DU-145 in vitro. RESULTS PESV treatment on these cells resulted in a significantly dose-dependent growth inhibition with a G1 phase arrest at 40μg/mL after 48h treatment. PESV treatment strongly induced expression of p27 (Kip1), but resulted in a decrease in cyclin E, one of cyclins involved in G1 progression. In other studies, PESV treatment also induced high apoptosis index (AI), confirmed by TdTmediated dUTP-biotin nick-end labeling (TUNEL) assay. Further, the apoptosis induction by PESV (40μg/mL) in DU145 cells was associated with an increase of pro-apoptotic protein Bax. CONCLUSIONS These results suggest that PESV modulates the expression of cell cycle-related and apoptosis-related proteins and induces growth inhibition and apoptosis of DU145 cells, providing a strong rationale for future studies to evaluate prevention or/and intervention strategies for PESV in pre-clinical prostate cancer models. KEYWORDS Prostate cancer, PESV, cell proliferation, cell cycle, apoptosis.