Study on the correlation between BRCA1 gene polymorphism and hrHPV infection in cervical precancerous lesions
Cervical squamous intraepithelial lesions are precancerous lesions caused by high-risk subtypes of human papillomavirus (HPV). The development and prognosis of these lesions may be impacted by host genetics. Sanger sequencing was applied to sequence the breast cancer susceptibility gene (BRCA1) exons in exfoliated cervical cells. Fifteen single nucleotide polymorphisms (SNPs) were identified in the entire exon of BRCA1. It was found that there were 8 missense mutations, 1 nonsense mutation, 4 synonymous mutations, and 2 mutations not located in the protein-coding regions. Functional prediction of BRCA1 missense and synonymous mutation sites was performed using PolyPhen-2, ESEFinder3.0, and SIFT online software. The rs39812263 alteration in the BRCA1 gene was found to be significantly different by the sequencing. A significant difference was observed in the alterations of BRCA1 gene rs398122630 between hrHPV and thin- prep cytology test (TCT) groups (p < 0.05), a negative correlation was observed with both hrHPV and TCT. The genotype and allele frequencies of the BRCA1 gene rs398122630 were significantly different from those of the control group (p < 0.05). Rs398122630 may play a protective role in the progression of cervical cancer. This site is a nonsense mutation, which may lead to the premature termination of protein translation. Subsequently, we queried the Gene Expression Omnibus (GEO) and found that the expression of BRCA1 gene RNA gradually increased in cervical normal epithelium, high-grade cervical intraepithelial neoplasia (CIN), and cervical squamous cell carcinoma (CSCC). Lentiviral vectors were used to construct stable cell lines with BRCA1 (breast cancer susceptibility gene 1) knockout and overexpression. The scratch healing rate of HeLa cells with BRCA1 knockout was significantly higher than that of the negative control group (P < 0.05), while the difference in scratch healing rate in the overexpression group was not statistically significant. Compared to the control group, the proportion of cells in the G1 phase increased in the BRCA1 downregulated group (KD1), while the proportion of cells in the G1 phase decreased in the overexpression group (P < 0.05). The percentage of cells in the S phase decreased in the downregulated group compared to the control group (P < 0.05), and the proportion of cells in the G2 phase increased in the overexpression group compared to the control group (P < 0.05), BRCA1 may be involved in the migration and cell cycle of HeLa cells.