The effect of mutations in the upstream regulatory region of HPV-16 on the activity of virus early promoter / 中国癌症杂志

ABSTRACT

Background and purpose:The incidence of cervical cancer is rather high in Xinjiang, which is closely associated with the infection of human papilloma virus type 16 (HPV-16). The purpose of this study was to analyze the variants and function of HPV-16 upstream regulatory region (URR) in the tissues of cervical cancer biopsies from Xinjiang.Methods:The DNAs were extracted from the tissues of cervical epithelial atypical hyperplasia (CIN) and cervical cancer biopsies. HPV-16URR segments were ampliifed by PCR. Based on the sequence analysis of the URR, the representativeURR variants were selected and cloned into pGL3-Basic. The recombinant plasmids were transfected into Vero cell lines respetively. Luciferase activity of transfected cells was detected 48 h after transfection. Results:Fifty-ifve HPV-16URR DNA fragments were obtained through PCR, and 44 mutations were found from the URR fragments. 4 of these mutations, including nt7192(G→T) , nt7433(- →T), nt7435 (C→G) and nt7863 (A→-) occurred in all sequences. The mutation at nt7520 (G→A) occurred in 54URR sequences, and the 39 other mutations were present in different samples. Based on the location and frequency of the mutations in theURR fragments, 9URR variants were selected and cloned into pGL3-Basic. Then the luciferase activity of the cells transfected with pGL3-URR plasmids was detected respectively. Promoter activity ofURR mutants from cervical cancer are significantly higher than that ofURR mutants from CIN (P<0.01). Promoter activity ofURR fragments from some cervical cancer was signiifcantly higher than that of theURR fragments from SiHa and Caski cells.Conclusion:Multiple mutations occurred in HPV-16URR of cervical cancer patients from Xinjiang. The promoter activity and carcinogenicity of some URR mutants have been enhanced.