[Mechanism study of protobioside on tumor cell proliferation].

OBJECTIVE

To investigate the anti-proliferative effect of Protobioside on the HepG2 cells and its mechanism.

METHOD

The inhibitory effects of Protobioside on 3 kinds of human cancer cell line was measured by MTT assay. Apoptotic morphological changes was observed by Hoechst33528 staining technique. Cell cycle were analyzed using flow cytometry. The expression of cell cycle related protein and apoptosis related protein were determined using Western blotting.

RESULT

Protobioside shows strong cytotoxic power on HepG2 cells and IC50 were 20 micromol x L(-1). The nucleus became pyknosis at 36 hours. The cells in G2/M phase increase in a dose-dependent and time-dependent manner. And the protein level of CyclinB1 was down-regulated, that of Bax was up-regulated and that of Bcl-2 was down-regulated.

CONCLUSION

The growth inhibition of Protobioside on HepG2 cells is highly related to cell cycle arrest at G2/M phase which was well correlated with the down-regulation of expression of Cyclin B1, and the induction of apoptosis via up-regulating of Bax and down-regulating Bcl-2 expression.