The Role Of PTEN Methylation In Papillary Thyroid Carcinoma Cells And The Effect Of Demethylating Agent On It

Objective To investigate the methylation status of promoter region of PTEN,a tumor suppressor gene,in human thyroid papillary carcinoma cell lines.And to study the effects of 5-Aza-2'-deoxyglycoside(5-Aza-CdR),a demethylation agent,on the DNA methylation.To determine whether DNA methylation inhibitor can affect PTEN expression level through regulating its promoter methylation level.Providing a molecular basis for the molecular mechanism and treatment of papillary thyroid carcinoma.Method Methylation-specific PCR(MSP)and Quantitative Real-time PCR(Real-Time PCR)were used to detect the PTEN methylation status and PTEN m RNA expression in human thyroid papillary carcinoma B-CPAP and normal thyroid Nthy-ori-3 using 5-Aza-CdR or not.The relationship between PTEN gene methylation and thyroid papillary carcinoma cells was expolred.Results(1)There was only an amplified fragment of methylated primer in B-CPAP,and no any amplified fragment in Nthy-ori-3.(2)The brightness of the methylated amplified product of PTEN was decreased in B-CPAP cell treated with 5-Aza-CdR;(3)PTEN gene m RNA expressed in B-CPAP cells and lessly expressed in Nthy-ori-3 cells.(4)The PTEN m RNA expression was significantly increased in B-CPAP cells treated with 5-Aza-CdR.The difference was statistically significant difference between the two groups which treated with 5-Aza-CdR or not(P <0.05).Conclusion(1)There exists PTEN methylation in B-CPAP cell line,but not in Nthy-ori-3 cell line.(2)The expression of PTEN methylation was significantly decreased in B-CPAP cell line with 5-Aza-CdR treatment.(3)PTEN m RNA expression was significantly increased in B-CPAP cell line treated with 5-Aza-CdR;(4)Demethylation agent can significantly induce PTEN demethylation and promote its expression in thyroid cancer cells.5-Aza-CdR may play a therapeutic role.