Objective     To study the effect of Janus kinase (JAK) inhibitor AG490 on the invasion and metastasis of human liver cancer SMMC-7721 cells and the role of JAK-STAT3 signaling pathway in regulation of liver cancer invasion.      Methods     SMMC-7721 cells were divided into control group

5 μmol/L AG490 treatment group and 10 μmol/L AG490 treatment group. Invasion and metastasis of liver cancer SMMC-7721 cells were detected with transwell chamber. Expression of MMP-2 mRNA and VEGF mRNA in liver cancer SMMC-7721 cells was detected by RT-PCR. Expression and activation of STAT3

MMP-2 and VEGF proteins in liver cancer SMMC-7721 cells was detected by Western blotting.      Results     The number of membrane-permeating SMMC-7721 cells was 74.6±6.3

58.2±7.2

and 38.2±5.7 in control group

5 μmol/L AG490 treatment group

and 10 μmol/L AG490 treatment group

respectively

48 h after AG490 treatment. The ability of SMMC-7721 cells to invade the artificial basement membrane was significantly lower in two AG490 treatment groups than in control group (P0.05). RT-PCR showed that the expression level of MMP-2 mRNA and VEGF mRNA was significantly lower in two AG490 treatment groups than in control group (P0.05). Western blotting showed that the activation level of STAT3 protein and the expression level of MMP-2 and VEGF were lower in two AG490 treatment groups than in control group (P0.05).      Conclusion     AG490 can down-regulate the expression of MMP-2 and VEGF by blocking the activation of STAT3

thus inhibiting the invasion of liver cancer SMMC-7721 cells in vitro.