Antiproliferative Effect On Human Hepatocellular Carcinoma Cells By DAPT And Its Related Mechanism

Objective:To investigate the effect of DAPT,a specific inhibitor of Notch signaling pathway, on hepatocellular carcinoma cell line HepG2 proliferation,cell cycle,apoptosis and the change of NICD and ICBP90.So we could investigate the effect of Notch signaling pathway on HepG2 proliferation.Methods:To study the inhibitive effects of DAPT on the proliferation of HepG2 cells by MTT assay,cell cycle and apoptosis distribution by flow cytometry(FCM).HepG2 was treated with DAPT,the expression of NICD and ICBP90 were analysised by Western Blot at 1,3,6,12, 24 h.Results:DAPT could inhibit the growth of HepG2 cell in a dose-dependent(r=0.86,P＜0.05) and time-dependent(r=0.55,P＜0.05) in vitro.DAPT could cause G₀/G₁ cell cycle arrest in HepG2 cells(r=0.90,P＜0.05),but this effect is not through down regulating the leval of ICBP90. DAPT could induce remarkable apoptosis in HepG2 cells(r=0.32,P＜0.01).The above cell cycle arrest and apoptosis was related to the activation of Notch signal pathway.Western Blot showed DAPT decreased the expression of NICD at different time(r=-0.75,P＜0.05),but the expression of ICBP90 was increased after treated by DAPT at different time(r=0.96,P＜0.05),especially at 24 h,the effect were more stronger.Conclusions:DAPT has effect on the proliferation and shows significant inhibition on HepG2. This inhibitory effect are concermed with that DAPT makes cells blocked in G₀/G₁ phase and inhibit them into S phase and G₂/M phase.So,we supposed that the activation of Notch signaliing pathway play a important role in the proliferation of HepG2 cell,and this process is probably not via ICBP90 derectly.