Promotion of HepG2 cell apoptosis by Sedum emarginatum Migo and the mechanism of action

Abstract

Background: Sedum emarginatum Migo(S. emarginatum) has anti-tumor and anti-oxidant effects. This study aimed to screen the extractions of S. emarginatum against liver cancer in vitro and explore its anti-liver cancer mechanism. Methods: The CCK-8(Cell Counting Kit-8) method was used to detect the inhibitory effect of different extracts of S. emarginatum on the proliferation of liver cancer HepG2 cells. The morphological changes of the cells after administration were observed with microscopy, cell apoptosis was detected by flow cytometry, and the expression of Bax, Bcl-2 and Caspase-3 mRNA in the cells were detected by RT-PCR (Reverse Transcription-Polymerase Chain Reaction) to explore the mechanism of action. Results: CCK-8 method test results showed that among the different extracts of S. emarginatum, the ethyl acetate extract(1000 μg/ml, 2000 μg/ml, 2500 μg/ml, 3000 μg/ml) and n-butanol extract(1000 μg/ml, 2000 μg/ml, 2500 μg/ml, 3000 μg/ml) have the strongest inhibitory effect on the proliferation of HepG2 cells. In these 4 concentrations, the inhibitory effect increased as the concentration increased. The IC50 of the ethyl acetate extract on HepG2 cells was less than that of the n-butanol extract, so the ethyl acetate extract has a better proliferation inhibitory effect on HepG2 cells than the n-butanol extract, followed by the 70% ethanol extract(3000 μg/ml) and the water extract(3000 μg/ml), petroleum ether extract was the weakest. The results of microscopy showed that ethyl acetate extract caused hepatocarcinoma HepG2 cell morphology changed, cell density decreased, and suspension cells increased. Moreover, the results of flow cytometry showed that the ethyl acetate extract of S. emarginatum could induce HepG2 cell apoptosis at the concentrations of 2500μg/ml and 3000μg/ml. RT-PCR results showed that the expression of Bax mRNA was up-regulate by the middle(2500 μg/ml) and high(3000 μg/ml) dose groups of ethyl acetate extract. The expression of Caspase-3 mRNA was up-regulated by the low(2000 μg/ml), medium(2500 μg/ml) and high(3000 μg/ml) dose groups of ethyl acetate extract. The expression of Bcl-2 mRNA was down-regulated by the high(3000 μg/ml) dose group of ethyl acetate extract. Conclusion: The ethyl acetate extract of S. emarginatum has the best effect on human liver cancer HepG2 cells. Its anti-hepatocellular mechanism may be related to affect the expression of apoptosis genes (Bax, Bcl-2 and Caspase-3mRNA) and promote the apoptosis of liver cancer cells. It provided a reference for the research and development of drugs for the treatment of liver cancer.