Proliferation Inhibition Effect Of GDF11 In Hepatocellμlar Carcinoma

OBJECTIVE: To explore the effect of GDF11 overexpression on SMMC-7721 cells proliferation ability and sensitivity to DDP in vitro. Methods: GDF11 overexpression SMMC-7721 cells were established by lentivirus infection(Lenti-GDF11 group). Meanwhile, empty vector infected cells(Lenti-GFP group) and wild type cells(Control group) were treated as control. Cells proliferation ability was examined by CCK-8 assay, and proliferation curve was calcμlated. Colony formation assay was adopted to evaluate colony formation ability. The SMMC-7721 cells were treated with various concentrations of DDP, then cell viability was measured by CCK-8 assay. Cell cycle was detected by flow cytometry. SMMC-7721 cells were divided into three groups: the Lenti-GDF11 group(GDF11 over-expression), Lenti-GFP group(empty plasmid infected), and control group. Nude mice were inoc μ lated subcutaneously with cells of each group to establish the subcutaneous tumor model of hepatocellμlar carcinoma. Tumor volumes in nude mice were measured, and the tumor growth curve was drawn. Tumor volume and weight were estimated. The expression of GDF11, Ki-67 and microvessel density were detected by immune histochemical method(SP-9000).RESULTS: 1. Western blot showed high protein expression of GDF11 in the gene-infected group than Lenti-GFP group and control group. 2. CCK-8 assay showed that over-expression of GDF11 coμld inhibit cell viability(P<0.05). 3. Meanwhile GDF11 over-expression group had lower ability in colony formation than control groups(P<0.05) 4. After treatment with different concentration of DDP for 24 h, CCK-8 assay showed that over-expression of GDF11 enhance SMMC-7721 cells sensitivity to DDP-induced proliferation inhibition in vitro(P<0.05) 5. GDF11 over-expression induced cell inhibition in G1 phase(P<0.05). 6. Compared with the control group and the Lenti-GFP group, tumor growth of Lenti-GDF11 group slowed less proliferation significantly(P<0.001). The meantumor weight in Lenti-GDF11 group was less than control groups(P<0.001). 7. The GDF11 expression in Lenti-GDF11 group was higher than control groups, meanwhile, the Ki-67 and MVD expression level were lower than control groups(P=0.006; P<0.001; P<0.001). 8. The correlation analysis showed that GDF11 expression has negative correlation with Ki-67 expression(R2=-0.668, P=0.002), meanwhile GDF11 expression has negative correlation with MVD(R2=-0.622, P=0.006).CONCLUSION: Overexpression of GDF11 coμld inhibit SMMC-7721 cell proliferation in vitro and in vivo. GDF11 sensitizes human hepatocellμlar carcinoma cell lines SMMC-7721 cells to DDP-induced apoptosis. The mechanism may be according to cell cycle arrest and decreased tumor microvessels.