Podophyllotoxin Lg-2Derivatives Induced Apoptosis In Human Hepatoma Cell Line HepG-2

Objective To study the apoptosis inducing effect and its mechanism ofN-(1-Oxyl-2,2,6,6-tetramethyl-4-piperidinyloxycarbonyl)-L-alanine4-demethyl-4-deoxypodophyllic ester(Lg-2)in human hepatoma cell line HepG-2.Methods The effect of Lg-2on HepG-2was observed by MTT, flow cytometry andHoechs33258staining. The apoptosis related genes p53, bax, bc1-2, p21and caspase3expression were detected by fluorescent quantitative RT-PCR (qRT-PCR).Results Lg-2was demonstrated to exert antiproliferative activity in a dose-andtime-dependence. With the increase of drug concentration, depressant effectstrengthen gradually. The inhibition of drug treatment group has significant difference(p<0.05) to VP-16treatment group. In addition, the inhibition has positive correlationto time extend. It also has significant difference between Lg-2treatment group andVP-16treatment group after12h to60h treatment(p<0.05).The proportion of cells in Sphase decreased while the proportion of cells in S/G2phase increased after24and48hours treated with Lg-2.Hoechst33258staining showed that the treated cell nuclearcondensation, fragmentation, showing apoptosis-like changes.The expression ofbc1-2mRNA decreased, while p53, Bax, p21, caspase3mRNA expression wasincreased following Lg-2treatment. Lg-2showed obvious anticancer activity bycausing cell cycle arrest and regulating the expression of apoptosic related gene..Conclusion Our results show that Lg-2possibly through cell cycle arrest in the G2phase inhibition of cell proliferation and induce apoptosis through the signalingpathways of p53, p21, caspase3to achieve the purpose of inhibiting tumor growth.This study provides a theoretical basis for the development of new liver canceradjuvant, will be conducive to guiding the conduct of the relevant pre-clinical studies.