Cervical cancer causes malignant tumors in females and threatens the physical and mental health of women. Current research shows that persistent infection of high-risk HPV is the main cause of cervical cancer. However, not all cervical cancer is caused by HPV infection, which may also be related to other factors, such as nutritional status and lifestyle. This study focuses on the effect of alcohol consumption on the methylation status of cervical cancer from the perspective of methyl donors. We established a mouse tumor-bearing model with cervical cancer SiHa cells, and at the same time, we cultured SiHa cells in vitro. Different concentrations of ethanol were administered to the model mice and SiHa cells. Then, we detected the levels of the methyl-donor folate and methionine and their metabolite homocysteine levels in mice serum, tumor tissues, and SiHa cells. Furthermore, we determined the expression of the members of the DNA methyltransferase family (DNMT1, DNMT3a, and DNMT3b) in tumor tissue by immunohistochemistry. qRT-PCR and Western blotting analysis were used to detect the mRNA and protein levels of members of the DNA methyltransferase family in cervical cancer SiHa cells. Our results show that the levels of the methyl donor (folate and methionine) decreased with the increase of ethanol concentration (p < 0.05), and the homocysteine level increased significantly (p < 0.05). In SiHa cells, the mRNA and protein levels of the DNMT family members and their receptors were significantly higher than those in the control group (p < 0.05). Collectively, these results suggest that ethanol could influence DNMT expression by inducing methyl donor consumption, thereby causing cervical cancer cells to exhibit genome-wide hypomethylation.
Keywords: DNA methylation; alcohol; cervical cancer; epigenetics.