Expression Of STAT3 In HCC And Effect Of 5-Aza-CdR And AG490 On It In HepG2 Cells

Objective: To investigate the expression of STAT3, SOCS1 and c–myb in hepatocellular carcinoma(HCC) as well as their significance in oncogenesis and development of HCC; To explore the effect of 5-Aza-CdR and AG490 on the expression of STAT3 mRNA and cell cycle, apoptosis of HepG2 cells.Methods: The expression of STAT3, SOCS1 and c–myb protein was examined with immunohistochemical technique in the specimens from HCC tissues; The apoptosis and the cell cycle of the HepG2 cells were detected by flow cytometry (FCM) after treated with 5-Aza-CdR and AG490 for 72h; The expression of STAT3 mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR).Result: The positive rate of STAT3, SOCS1 and c﹣myb protein expression were markedly higher in HCC tissues (all P < 0.01); There was a positive correlation between the expression of SOCS1和STAT3 in HCC(rs=0.431, P < 0.01); FCM analysis showed that the G0/G1-phase fraction of HepG2 cells increased significantly at 100μM 5-Aza-CdR( P<0.01), and at two regeants(treated with 10μM 5-Aza-CdR and 10μM AG490,P < 0.01); The S-phase and G2/M-phase fraction of HepG2 cells increased markedly at 100μM AG490(all P<0.01); The apoptosis rates in HepG2 cells were increased significantly after exposure to 5-Aza-CdR and AG490(1μM,10μM and 100μM) for 72 h, respectively(all P < 0.01);and the apoptosis rate in HepG2 cells exposure to 10μM 5-Aza-CdR and 10μM AG490 for 72 h was increased significantly compared with in HepG2 cells treated with 10μM 5-Aza-CdR or 10μM AG490(all P <0.01). The expression of STAT3 mRNA was decreased significantly in HepG2 cells after the treatment with 5-Aza-CdR for 48h or 72h(all P<0.01).Conclusion: The expression of STAT3, SOCS1 and c﹣myb was increased in HCC tissues, it mihgt take part in the development of HCC; 5-Aza-CdR and AG490 could block different phase of cell cycle and induce apoptosis of HepG2 cells; And meanwhile,5-Aza-CdR could inhibit the expresson of STAT3 mRNA.