The chemopreventive role of 5-methoxypsoralen (5-MOP) in the human hepatocellular carcinoma (HCC) cell line was investigated
by studying the regulation of proliferation and apoptosis in HCC (J5) cells. Morphological analysis, cell viability assay, DNA
analysis and cell-cycle analysis suggest that there are at least three modes of the suppressive effects shown by 5-MOP: (a) kills J5
cells directly; (b) induces apoptosis by arresting J5 cells at the G2/M phase in the cell cycle; (c) induces apoptosis through an
independent pathway with cell-cycle arrest at 24–72 h of exposure. Further immunoblot analysis demonstrated that inhibition of
cyclin B1 by 5-MOP may play an important role in G2/M arrest of J5 cells and provides an additional way to prevent cells from
entering the M phase and undergoing apoptosis. 5-MOP therefore appears to exert its anticarcinogenic properties by cytotoxic
effect, inducing apoptosis and inhibiting proliferation in the human hepatocellular carcinoma cell line.
