SOCS3基因对肺腺癌细胞株A549中c-Myc表达的影响

目的探讨SOCS3基因对人肺腺癌细胞株A549中c-Myc表达的调控作用。方法以脂质体为载体将pEFSOCS3和pSV2neo共转染至人肺腺癌细胞株A549,RT-PCR和免疫细胞化学法测定转染前后细胞中SOCS3mRNA和蛋白表达;Westernblot检测STAT3蛋白酪氨酸磷酸化水平变化;sqRT-PCR测定转染前后细胞中c-MycmRNA的表达。MTT法检测转染前后细胞增殖变化。结果RT-PCR和免疫细胞化学证实转染后细胞中SOCS3稳定表达;Westernblot证实pEFSOCS3转染组细胞STAT3蛋白酪氨酸磷酸化水平明显降低(P <0.01);sqRT-PCR显示pEFSOCS3转染组细胞中c-MycmRNA的表达显著降低。MTT法结果示pEFSOCS3转染组细胞增殖明显受到抑制。结论SOCS3蛋白可能通过抑制A549细胞中STAT3蛋白的酪氨酸磷酸化从而下调c-Myc基因的表达,最终抑制A549增殖。

Effect of SOCS3 gene on expression of c-Myc in human lung adenocarcinoma cells

To explore the effect of SOCS3 gene on the expression of c-Myc in human lung adenocarcinoma A549 cells. A549 cells were cotransfected with pEFSOCS3 and pSV2neo by liposome. Expression of SOCS3 mRNA and protein were detected by RT-PCR and immunocytochemistry respectively. Tyrosine-phosphorylated Stat3 level was measured by Western blot analysis. The expression of c-Myc mRNA was detected by sqRT-PCR. MTT assay was used to detect the cell proliferation. The SOCS3 expression was confirmed by RT-PCR and immunocytochemistry in A549 cells transfected with pEFSOCS3 respectively. Tyrosine-phosphorylated Stat3 level decreased significantly in pEFSOCS3-transfected A549 cells,and the expression of c-Myc mRNA was significantly lower. MTT assay showed inhibition of proliferation in pEFSOCS3-transfected A549 cells. [Conclusion] SOCS3 downregulates the expression of c-Myc mRNA by lowering the tyrosine-phosphorylated level of STAT3 protein, which may play an important role in inhibiting A549 cells proliferation by SOCS3.