Abstract:

Objective To explore the effects of different doses of 5,2',4'-trihydroxy-6,7,5'-trimethoxyflavone nanoparticles (TTF1-NP) on theapoptosis of human hepatoma cells and human normal hepatocytes, and to explore their mechanisms through endoplasmic reticulum stress (ERS)-meditated apoptosis pathway. Methods The human hepatoma cell lines (HepG2,Hep3B and PLC/PRF/5) and human hepatocytes (Chang Liver) were used as cell model,and divided into vehicle,5-Fu and TTF1-NP treated groups with the concentrations of 50,100 and 200 μmol·L^-1 respectively. The inhibitory effects of TTF1-NP on the cell growth were assessed using MTT assay and the best inhibitory one (HepG-2) was selected as the main research cell lines.Flow cytometry was used to detect the TTF1-NP-induced apoptosis; Western blotting and immunocytochemistry were used to determine the expressions of ERS key proteins.Finally,the expressions of key proteins were detected by Western blotting after using the ERS inhibitor 4-PBA. Results Compared with vehicle group,the inhibitory rates of growth of 4 kinds of human hepatoma cells in different concentrations of TTF1-NP groupswere increased(P<0.05 or P<0.01); moreover,the inhibitory effects of TTF1-NP were in a time-and dose-dependent manner.Compared with vehicle group,the apoptotic rates of the cells in TTF1-NP groups were increased in a dose-dependent manner(P<0.05 or P<0.01); the expression levels of ERS key proteins GRP78 and caspase-4 were increased with the increasing of the concentration of TTF1-NP(P<0.05 or P<0.01).The expression levels of ERS key proteins GRP78 and caspase-4 induced by TTF1-NP were inhibited by ERS inhibitor 4-PBA(P<0.05 or P<0.01). Conclusion TTF1-NP can induce the apoptosis of HepG2 cells; ERS pathway plays a central role in TTF1-NP-induced apoptosis of HepG-2 cells.

Key words: 5,2',4'-trihydroxy-6,7,5'-trimethoxyflavone nanoparticles, endoplasmic reticulum stress, apoptosis, liver neoplasms