Melatonin induces antiproliferative activity through modulation of apoptotic pathway in H-ras oncogene transformed 5RP7 cells

Abstract

In the present study, cytotoxic and apoptotic effects of melatonin were investigated on H-ras oncogene transformed rat embryo fibroblast 5RP7 cells. Melatonin inhibited cell growth and induced apoptosis in 5RP7 cells. We showed inhibition of cell proliferation that was time- and dose-dependent in 5RP7 cells for 24 and 48 h. Melatonin was not toxic in NIH/3T3 primary mouse embryonic fibroblast cells at low doses for 24 and 48 h. The IC50 (380 mu M) value of melatonin for 48 h was chosen for advanced assays. The percentages of early/late apoptotic cells to which melatonin (IC50 : 380 mu M) was administered were increased 6.2-fold in 5RP7 cells compared to controls for 48 h. The melatonin treatment resulted in increased caspase-3 activity and reduced the mitochondrial membrane potential in the 5RP7 cells for 48 h. The cell cycle arrest caused by melatonin was observed in G1 and G2 phases in the cell cycle analyses in 5RP7 cells for 48 h. These findings show that melatonin induces cell death and apoptosis in H-ras oncogene transformed 5RP7 cells. Melatonin may be an anticancer agent against H-ras oncogene activated cancer cells.