Proliferation and apoptosis of choriocarcinoma cell JEG-3 induced by VB2 and its in vitro mechanism

Abstract

To investigate the effect of purified vitexin compound 2 (VB2), a noval lignanoid from the acetoacetate extract of Vitex negundo seed on the proliferation and apoptosis as well as the expression of mTOR and 4E-BP1 mRNA signal pathway in human choriocarcinoma JEG-3 cell lines in vitro. The inhibitory effect of different concentrations of VB2 on JEG-3 cells was examined by methyl thiazolyl tetrazolium (MTT) assay. Flow cytormetry was used to analyze the apoptosis after using different concentrations of VB2, and the expression of mTOR and 4E-BP1 mRNA was determined by RT-PCR. The inhibitory rate of JEG-3 cell growth which was cultured with different concentrations of VB2 (2.5, 5.0, 10.0, 20.0, 40.0, 80.0, and 160.0 μmol/L) for 24, 48, or 72 hours increased from (6.34±0.41)% to (85.89±0.81)%, and it was positively correlated with the dose and time of culture (P<0.05). VB2 at 5.0, 10.0, or 20.0 μmol/L increased the rate of JEG-3 cell apoptosis in vitro from (9.26±1.02)% to (35.55±1.24)% after 48 hour culture, which was in a dose dependent manner (P<0.05), while 5.0, 10.0, or 20.0 μmol/L of VB2 down-regulated the mRNA levels of mTOR and 4E-BP1 after 48 hour culture, which presented a significant negative correlation between VB2 and the mRNA levels of mTOR and 4E-BP1(P<0.05). VB2 can restrain the proliferation of choriocarcinoma cell JEG-3 and induce its apoptosis. This effect may be related to the inhibition of VB2 on the mRNA expression of JEG-3 cell mTOR and 4E-BP1.