ABSTRACT
Objective To evaluate the expression of RAR-? gene in cervical carcinoma cell lines SiHa,HeLa,C33A and Caski and to analyze the relation between their gene expression and the promoter methylation of RAR-? DNA.Methods The expression of mRNA and protein of RAR-? gene in the four cell lines were analyzed by RT-PCR,western blot and immunofluoreseence,respectively.Methylation specific PCR(MSP)was used to check whether there was methylation in the promoter of RAR-? gene.The demethylating agent 5-aza-2'-deoxycytidine(5-Aza-cdR)was used to treat methylated cell lines and the change of RAR-? gene methylation and RAR-? gene expression defects were observed.The cell proliferation was assayed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method.Results The mRNA and protein expression levels of RAR-? in cell lines SiHa,HeLa,Caski and C33A were 0.25 ?0.08,0,0.60?0.19,3.12?0.92 and 0.23?0.07,0,0.14?0.05,0.68?0.21,respectively.The mRNA and protein expression of RAR-? in SiHa,HeLa and Caski cell lines were decreased or silenced, whereas its expression increased in C33A cell line.MSP method showed that there were RAR-? gene methylation in SiHa,HeLa and Caski cell lines,while there was no RAR-? gene methylation in C33A cell line.After treated with 5-Aza-cdR,the mRNA and protein expression levels of RAR-? in SiHa,HeLa, Caski and C33A cell lines were 1.82?0.59,2.13?0.62,1.67?0.43,2.95?0.89 and 0.69?0.21, 0.83?0.29,0.56?0.16,0.64?0.20 respectively.The mRNA and protein levels of RAR-? had a significant difference between before and after interference with 5-Aza-cdR in SiHa,Helm,and Caski cell lines(P0.05).The 5-Aza-cdR treatment could suppress cell proliferation.Conclusions The RAR-? gene expression defects play an important role in the carcinogenesis of cervical cancer.Aberrant methylation in promotor region of RAR-? gene may be an important mechanism for the loss of expression of RAR-? gene.