Association between APOBEC3s and HPV16 E2 gene hypermutation in Uygur females with cervical cancer

The present study aimed to investigate whether apolipoprotein B mRNA-editing enzyme catalytic polypeptides (A3) are involved in the regulation of cervical cancer development and human papilloma virus (HPV)16 sustained infection in Uighur females. Cervical tissues of Uygur patients with HPV16 with cervical lesions were collected. Expression levels of A3C, A3F and A3G were detected using reverse transcription-quantitative PCR and western blotting. A model of SiHa cells with high expression levels of A3C, A3F and A3G was constructed. Hypermutation was detected using the differential DNA denaturation PCR and positive samples were amplified and sequenced. There were significant differences in A3 expression levels in cervical lesions of different grades. A3C and A3F mRNA and protein expression in cervical cancer tissues were significantly lower, whereas the A3G mRNA and protein expression levels were significantly higher compared with the cervicitis and cervical intraepithelial neoplasia (CIN) I-III groups. Hypermutation rates were increased with cervical lesion development. C>T and G>A base substitutions were detected in all hypermutation samples and numbers of C>T and G>A base substitutions in single samples in the cervical cancer group were significantly higher compared with those in the CIN I-III and cervicitis groups. Following transfection of A3F and A3G, HPV E2 mRNA and protein expression levels were significantly decreased in SiHa cells. Numerous C>T and G>A base substitutions were detected in the HPV E2 gene in A3G and A3C overexpressing SiHa cells. A3 family proteins inhibit viral replication during HPV16 infection and regulate the HPV16 integration by inducing C>T and G>A hypermutations in the HPV16 E2 gene, thus affecting the cervical cancer pathogenesis and development.