Abstract:
OBJECTIVE To investigate the apoptosis effect and mechanism of
Nervilia fordii methanol extracts(NFME) on human hepatic carcinoma SMMC7721 and HepG2 cells
in vitro.
METHODS UV-visible spectrophotometric method was used to determine total flavonoids and total polyphenols in NFME. The growth inhibition rate of SMMC7721, HepG2 and LO2 treated with different concentrations(0, 0.25, 0.5, 1, 1.5, 2 mg·mL
-1) of NFME for 24 h were detected by MTT. The effect of NFME on the colony formation rate of SMMC7721 and HepG2 cells was observed by clonal test. The effect of NFME on SMMC7721 cell apoptosis was observed by Hoechst apoptosis staining. The effect of NFME on SMMC7721 cell apoptosis and cell cycle were detected by flow cytometry. The phosphorylation level expression of caspase3 and ERK1/2 and c-Raf protein were detected by Western blotting.
RESULTS The total polyphenol content in NFME was (4.25±0.46)mg·g
-1, and the total flavonoid content was (4.72±0.13)mg·g
-1. The results of MTT experiments showed that compared with the control group, 0.5 mg·mL
-1 NFME could inhibit the proliferation of SMMC7721 and HepG2 cells(
P<0.001); the experiment of clonal formation ability showed that 0.125 mg·mL
-1 NFME could inhibit the formation of SMMC7721 and HepG2 cell colonies(
P<0.001); Hoechst apoptosis staining observed that 0.25 mg·mL
-1 NFME induced apoptosis of SMMC7721 cells for 24 h(
P<0.05); the flow cytometry results confirmed that 0.5 mg·mL
-1 NFME could induce apoptosis of SMMC7721 cells(
P<0.01), and apoptosis rate reached 14.43%, blocked cell cycle in S phase; Western blotting results showed that NFME could make caspase3 in SMMC7721 cells undergo shearing, the shear effect became more pronounced with concentration increasing(
P<0.05), and activated caspase3 shears downstream PARP expression; meanwhile, NFME could reduce the phosphorylation level of ERK1/2 and c-Raf proteins in SMMC7721 cells(
P<0.05).
CONCLUSION The NFME can inhibit the activity of human hepatocellular carcinoma SMMC7721 and HepG2 cells and induces apoptosis The mechanism of induces apoptosis may be related to the inhibition of ERK signaling pathway.