Effect of the SOCS3 expression activates IL-6/STAT3 signal pathway via Abnormal methylation alteration of IL-6 in colorectal cancer

Objective To detect the methylation status,mRNA expression of IL-6 and SOCS3 genes and the mRNA expression of STAT3 gene as well in colorectal cancer( CRC). Furtherly,to explore the effect of methylation of IL-6 on SOCS3 gene expression and consequently on the IL-6/STAT3 pathway. Methods The expressions of IL-6,SOCS3,STAT3 mRNA were detected by quantitative reverse transcription polymerase chain reaction( QRT-PCR). The methylation status of SOCS3 and IL6 genes promoter CpG island were assayed by methylation specific PCR( MSP) and bisulfite sequencing PCR( BSP),respectively. Results The expressions of IL-6、STAT3 in CRC were significantly up-regulated,while SOCS3 expression was significantly reduced. There was a negative correlation between IL-6 and SOCS3 expression in cancer tissue; Moreover,SOCS3 was shown and the methylation levels of IL-6 start sub-633,-611,-575,-575bp sites were much lower in cancer tissue than those in the adjacent tissues( P 0. 05). Conclusion Abnormal methylation status of IL-6 and SOCS3 caused gene expression changes and induced activation of the IL-6/STAT3 signaling pathway,which may contribute to the pathogenesis of colorectal cancer.