Abstract:

OBJECTIVE: To analyze the expression and methylation of SOX30 gene in colorectal cancer cell lines and colorectal cancer tissues. METHODS:The mRNA expression and methylation of SOX30 were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and methylation specific PCR (MSP). Demethylation experiment with 5-Aza-CdR was used to confirm the regulation of SOX30 expression by DNA hypermethylation. The methylation of SOX30 was further confirmed by sodium bisulfite DNA sequencing (BSP). RESULTS:Hypermethylation of SOX30 gene was found in all the colorectal cancer cell lines, with reduced mRNA expression. The mRNA expression of SOX30 increased in colorectal cancer cell lines treated with 5-Aza-CdR, indicating that SOX30 expression was regulated by DNA methylation. SOX30 hypermethylation was found in most of the colorectal cancer tissues (79.6%) , but not in tumor adjacent tissues (20%). After investigating possible associations between SOX30 methylation and clinicopathologic features, we found that SOX30 hypermethylation was associated with histological type, but not correlated to gender, age, smoking, clinical TNM stages and Ducks stages. CONCLUSION:Down-regulation of SOX30 by hypermethylation was always found in colorectal cancer cell lines, and its hypermethylation was obviously associated with histological type, suggesting SOX30 playing an important role in the carcinogenesis of colorectal cancer.

Key words: SOX30, DNA methylation, colorectal cancer, methylation specific PCR, bisulfite squencing PCR