Erianin induces apoptosis in human leukemia HL-60 cells.

AIM: To investigate the effect of erianin on human HL-60 cell line and explore its mechanism of apoptosis in vitro. METHODS: Inhibition of proliferation was measured with colorimetric MTT assay. The morphologic changes were observed by fluorescence and electron microscopes. DNA fragmentation was visualized by agarose gel electrophoresis, and the DNA degradation was determined by flow cytometry. Immunohistochemical analysis was used to identify the expression of bcl-2 and bax genes. RESULTS: The growth of human HL-60 cells was significantly inhibited by erianin 20-81.9 nmol/L during 72 h treatment (P < 0.01). The IC50 value was 38 nmol/L after a 24-h exposure to erianin, while that of vincristine, the positive control, was 101 nmol/L. The typical morphologic changes were observed and the nuclear DNA fragmentation exhibited "ladder" pattern. The cell cycle of HL-60 cells was arrested in G2/M phase, and expression of bcl-2 gene was decreased while that of bax was increased. CONCLUSION: Erianin showed potent inhibitory activity on the proliferation of HL-60 cells. The inhibition might be relative to the apoptosis induced by erianin and the altered expression of bcl-2 and bax genes in HL-60 cells.