The Preliminary Discussion Of The Effects Of ATRA And Its Derivatives On The Differentiation, Apoptosis And Mechanisms Of OPN Expression In HepG2 Cells

Objective To investigate the mechanism on the expression of OPN in human hepatoma HepG2 cells treated with ATRA. To sort out the effective medicine from a range of new synthetic derivatives of retinoic acid on this basis, and to study their mechanisms of apoptosis-inducing and the changes on OPN expression. Methods The expression of OPN, P-Erk1/2, Erk1/2 were detected by western-blots in HepG2 treated with ATRA then added in stimulator and inhibitor of Erk1/2 pathway. MTT was used to primarily sort out the effective medicine. The diversity ofγ-GT and AFP were detected by kinetics analysis. The cell apoptosis was measured with Hoechst dyeing and flow cytometry. The the expression of apoptosis-related proteins and OPN were studied by western blot. Results Application of PD98059 caused a dramatic reduction of PMA induced OPN expression. The specific activities ofγ-GT and the secretary amount of AFP significantly decreased. The results of flow cytometry and Hoechst dyeing showed two of the drugs can be markedly induced apoptosis of HepG2. Expression of OPN, Bcl-2, Bcl-xs/l were also decreased . Conclusion Activiation of Erk1/2 pathway can reverse the inhibition of the exprssion of OPN by ATRA in HepG2 cells. Of which the drugnamed"(all-E)-3,7-Dimethyl-9-(2,6,6trimethylcyclohexenyl)-2,4,6,8-nonatetraenoic -acid 4-amino-2-tri-fluoromethyl-phenyl ester"is superior to ATRA in the same con-centration at the same action time. This provides experimental supportings for seeking new medicine to induce the differentiation of hepatoma.