Correlation between dsRNA-induced PTEN gene activation and CpG island methylation in the promoter region

Abstract

Objective To evaluate the phosphatase and tensin homolog deleted on chromosome ten (PTEN) gene activation induced by double-standed RNA (dsRNA) in lung cancer cell line and its correlation with CpG island methylation in the promoter region. Methods Specific dsRNA complementary to the non-CpG island sequence in the promoter of PTEN gene was designed and transfected into H292 and A549 cell lines, and the expression of PTEN mRNA was determined by real-time quantitative polymerase chain reaction (PCR). The methylation status of the CpG island in the promoter region was tested by DNA sequencing on the bisulfate modified DNA. Results By testing several dsRNA sequences targeting promoter region of PTEN, a dsRNA named PTEN2-2 (target on -57 to -38 of the PTEN) was identified, which could upregulate the PTEN expression by 5.1 times at most (P 0.05), as the DNA methyltransferase inhibitor did (5±3 vs 10±4, 6±3 vs 9±3, both P<0.05). Conclusion The expression of PTEN mRNA could be enhanced by inducing the dsRNA into the cells, but no evidence was found that dsRNA could affect the methylation status of the CpG island in the promoter region of this gene. Key words: dsRNA; RNAa; PTEN; DNA methylation