Cigarette Smoke Regulates the Expression of EYA4 via Alternation of DNA Methylation Status.

Cigarette SMOKE (CS) considerably contributes to causing some diseases such as cancer, and it has a role in the alternation of gene expression through several mechanisms including epigenetics modification, particularly DNA methylation. is one of the genes, that whose expression has been dysregulated in lung, colon, bladder, and breast cancer, leading to tumor progression. The alternation of DNA methylation levels has been implicated in regulating the expression of the gene. Thus, in this study, we have shown the effect of CS on the DNA methylation level of the promoter region as well as the methylation level on expression. To determine the level of DNA methylation on the promoter region of the gene, we have employed the bisulfite conversion treatment followed by the Sanger Sequence for 100 DNA samples taken from Saudi people (50 smokers and 50 nonsmokers). We found that 26% of DNA extracted from smoker samples is methylated, while there was no methylation identified in nonsmoker samples. Also, using the demethylating agents such as AZA on LoVo and Caco-2 cancer cell lines causes induction of transcription level of , implying the possible mechanism of DNA methylation in the upregulation of . These findings suggest the possible mechanism of CS in controlling the expression of via changing the status of DNA methylation.