siRNA-mediated Inhibition of MTH1 Gene Expression Promotes Apoptosis and Reduces Migration of Hepatocellular Carcinoma HepG2 Cells

Objective To investigate the inhibitory effect of small interfering RNA(siRNA) on the expression of MTH1 in human hepatocelluar carcinoma HepG2 cells, and to observe the effect of MTH1 silencing on the apoptosis and migration of human hepatocelluar carcinoma HepG2 cells.

Methods Three pairs of specific siRNA targeting MTH1 were designed, synthesized, and then transiently transfected into HepG2 cells via cationic liposome transfection method. In vitro cultured HepG2 cells were divided into normal control group, negative control group and three transfection groups: MTH1-siRNA1, MTH1-siRNA2, MTH1-siRNA3. Then the protein levels of MTH1 were detected by Western blot, and we selected the best interfered MTH1-siRNA. Cell apoptosis was assessed by flow cytometry, and cell migratory ability was determined by wound healing assay.

Results MTH1-siRNA3 had better interfering effect than control normal group and negative control group ((0.24±0.072) vs. (0.87±0.068) and (0.24±0.072) vs. (0.84±0.086), P=0.002 and P=0.005). Flow cytometry analysis showed that cell apoptosis rate was significantly higher in the MTH1-siRNA3 group than those in normal control group and negative control group ((21.81±3.58) % vs. (5.49±2.18)%, and (21.81±3.58)% vs. (6.47±2.41)%, P=0.012 and P=0.013). Wound healing assay suggested that the relative migration abilities of HepG2 cells in the MTH1-siRNA3 group at 24, 36h after transfection were significantly lower than those in normal control group and negative control group ((51.35±4.25)% vs. (70.33±3.58)% and (51.35±4.25)% vs. (69.28±3.67)%, P=0.001, (82.16±2.39)% vs. (99.28±0.43)% and (82.16±2.39)% vs. (98.68±0.47)%, P=0.000).

Conclusion MTH1 plays an important role in the apoptosis and migration of HepG2 cells. The inhibition of MTH1 expression could promote the apoptosis and reduce the migration of hepatocellular carcinoma HepG2 cells.