Involvement of human beta-defensin-2 in regulation of malignant potential of cultured human melanoma cells

Abstract

Background and Aim: Human beta-defensin-2 (hBD-2) is an antimicrobial cationic peptide capable to control human carcinoma cell growth via cell cycle regulation. The present study was aimed on determination of hBD-2 influence on the growth patterns and malignant potential of cultured human melanoma cells. Methods: The study was performed on cultured human melanoma cells of mel Z and mel Is lines treated with recombinant hBD-2 (rec-hBD-2); cell viability, proliferation, cell cycle distribution, and anchorage-independent growth were analyzed using MTT test, direct cell counting, flow cytometry, and colony forming assay respectively. Expression and/or phosphorylation levels of proteins involved in cell cycle control were evaluated by Western blotting. Results: The treatment of mel Z and mel Is cells with rec-hBD-2 in a concentration range of 100–1000 nM resulted in a concentration-dependent suppression of cell proliferation, viability, and colony forming activity. It has been shown that rec-hBD-2 exerts its growth suppression effects via significant downregulation of B-Raf expression, activation of pRB and upregulation of p21WAF1 expression, downregulation of cyclin D1 and cyclin E resulting in cell cycle arrest at G1/S checkpoint. Conclusion: According to obtained results, hBD-2 exerts its growth suppression effect toward human melanoma cells via downregulation of B-Raf, cyclin D1 and cyclin E expression, upregulation of p21WAF1 expression and activation of pRB. Key Words: human beta-defensin-2, melanoma, proliferation, viability, cell cycle, B-Raf, anchorage-independent growth.