SFRP1基因启动子甲基化在甲状腺乳头状癌中的表达及意义

目的检测甲状腺乳头状癌(papillary thyroid cancer,PTC)组织中SFRP1基因启动子DNA甲基化状态,分析其与临床特征和生化指标的相关性及对mRNA表达的影响,探究其在临床应用中的价值。方法选择2017年10月至2019年10月在烟台市烟台山医院行手术治疗的97例初发PTC患者作为研究对象,取患者的PTC组织(观察组)和癌旁组织(对照组),采用甲基化特异性PCR(methylation special PCR,MSR)检测组织中SFRP1基因启动子区甲基化状态,采用荧光定量PCR法检测SFRP1基因mRNA表达量,使用甲基转移酶抑制剂5-Azacytidine处理PTC细胞株,且进行生化指标的检测和临床特征的收集。结果PTC组织的SFRP1基因启动子区甲基化阳性率(70.1%)显著高于癌旁组织的甲基化阳性率(33.0%)(χ2=26.747,P<0.001);PTC组织的SFRP1基因mRNA表达量显著低于癌旁组织的mRNA表达量(t=2.886,P=0.007),甲基化阳性PTC组织的mRNA表达量也显著低于甲基化阴性PTC组织mRNA的表达量(t=2.065,P=0.038)。随着5-Azacytidine浓度的增加,CGTHW-3细胞SFRP1基因mRNA表达量也逐渐上升。此外,PTC组织中甲基化阳性率与TNM分期(χ2=5.487,P=0.019)和是否有淋巴结转移(χ2=4.659,P=0.031)有关,且甲基化组的血清TSH和TGAb水平均高于非甲基化组(TSH:t=2.234,P=0.023;TGAb:t=2.312,P=0.021)。结论SFRP1基因启动子区高DNA甲基化可通过下调该基因mRNA表达,参与到PTC的发生、发展中。

Expression and significance of SFRP1 gene promoter methylation in papillary thyroid carcinoma

Objective To investigate the value of SFRP1 gene promoter methylation in PTC tissues,to eanalyze its correlation with clinical characteristics and biochemical indicators and its effect on mRNA expression,and to explore its value in clinical applications.Methods 97 patients with first-onset PTC were selected as the research subjects,and the patients’PTC tissues(observation group)and adjacent tissues(control group)were taken.Methylation-specific PCR(MSR)was used to detect the methylation status of the SFRP1 gene promoter region,and mRNA expression was measured by fluorescent quantitative PCR.The methyltransferase inhibitor 5-Azacytidine was used to treat thyroid papillary cancer cell lines,detection of biochemical indicators and collection of clinical characteristics.Results The positive rate of methylation of SFRP1 gene promoter region(70.1%)in PTC tissues was significantly higher than that of adjacent tissues(33.0%)(χ2=26.747,P<0.001);the expression of SFRP1 gene mRNA in PTC tissues was significant MRNA expression in tissues adjacent to cancer(t=2.886,P=0.007),mRNA expression in methylated positive PTC tissues was also significantly lower than that in methylated negative PTC tissues(t=2.065,P=0.038);with the concentration of 5-Azacytidine increased,the expression of SFRP1 gene mRNA in CGTHW-3 cells also gradually increased.In addition,the positive methylation rate in PTC tissues was related to the TNM stage(χ2=5.487,P=0.019)and whether there was lymph node metastasis(χ2=4.659,P=0.031).The levels of TSH and TGAb in the methylation group were higher than those in the unmethylated group(TSH:t=2.234,P=0.023;TGAb:t=2.312,P=0.021).Conclusion High DNA methylation in the promoter region of SFRP1 gene can participate in the occurrence and development of PTC by down-regulating the mRNA expression of genes.