Objective To detect the methylation status of SALL3 gene promoter region in normal cervical tissues,cervical cancer tissues,and cervical cancer cell lines and thus explore the relationship between methylation status and the expression of SALL3 gene.Methods The DNA methylation statuses of SALL3 gene in normal cervical,cervical cancer tissues and cervical cancer cell lines were analyzed by methylation-specific PCR(MS-PCR).The expressions of SALL3 mRNA in cervical cancer cell lines,cervical cancer tissues,and normal cervical tissues were detected by RT-PCR.Results In cervical cancer and matched peri-carcinomatous samples,the methylation levels of SALL3 were up-regulated(CCa vs.CCap:P=0.046;CCa vs.NC P=0.039)and the protein expressions were down-regulated(CCa vs.CCap:P=0.012;CCa vs.NC P=0.000)when compared with normal cervix samples.The mRNA levels of SALL3 in HeLa and SiHa cells treated with 5-Azacytidine were elevated in a dose-dependent manner(HeLa:P=0.001;SiHa:P=0.002).The methylation level of SALL3 was higher in high risk human papillomavirus(HPV)-positive cervical samples than in HPV-negative cervical samples(P=0.014),which also resulted in a descending SALL3 expression in HPV-positive samples(P=0.021).Conclusions The hypermethylation of SALL3 in promoter regions inhibits the expression of SALL3 in cervical cancer tissue samples.Infection with high-risk HPV serotypes may increase the methylation of SALL3 promoter region,silence its expression,and thus promote the development of cervical cancer.
Keywords: SALL3 gene; cervical cancer; high risk human papillomavirus; methylation.