维吾尔族妇女宫颈病变与CALCA基因启动子甲基化的关系

The association of cervical lesion pathogenesis in Uighur women and promoter methylation of CALCA gene

目的:研究维吾尔族妇女宫颈病变与降钙素相关肽α(calcitonin-related polypeptide alpha,CALCA)基因启动子区CpG位点甲基化的关系,进一步揭示宫颈癌组织中该基因表达调控的表观遗传学机制。方法:收集维吾尔族妇女宫颈病变患者手术切除或活检组织标本50例,其中宫颈鳞癌(cervical squamous cell carcinoma,CSCC)25例、宫颈内上皮内瘤样变(cervical intraepithelial neoplasia,CIN)9例及慢性宫颈炎16例,应用Sequenom MassARRAY甲基化DNA定量分析平台,对组织DNA的CALCA基因启动子区CpG位点进行甲基化水平的定量分析。结果:宫颈炎、CIN和CSCC组织中CALCA基因启动子区CpG片段甲基化率分别为0.22、0.26和0.33,经统计学分析,CSCC与CIN以及CSCC与宫颈炎之间均有显著差异(P<0.05)。从单一CpG位点角度分析,CSCC与宫颈炎组织CpG-2、CpG-3、CpG-9.10.11和CpG-12等6个CpG位点甲基化率均有显著差异(P<0.05)。结论:CALCA基因启动子甲基化与维吾尔族妇女宫颈癌发生密切相关,其中特定CpG位点甲基化水平变化可能成为宫颈癌早期诊断的分子标志物。

OBJECTIVE： To study the association of cervical lesion development of Uighur women with CpG site specific methylation of calcitonin-related polypeptide alpha （CALCA） gene at the promoter region, to further reveal the epigenetic regulatory mechanisms of this gene expression in cervical cancer. METHODS ： We collected 50 samples of fresh tissues in Uighur women with cervicitis（16 cases）, cervical intraepithelial neoplasia （CIN） （9 eases） and cervical squamous cell carcinoma（CSCC）（25 cases）. We analyzed quantitatively the CpG methylation level of CALCA at the promoter region in tissue DNA by Sequenom MassARRAY platform. RESULTS： We found target CpG fragment methylation of CALCA at the promoter region specific to papillary thyroid cancer with statistical difference, in comparison to the normal control. Further analysis of CALCA for single CpG site methylation indicated that the methylation of CpG- 2, CpG-3, CpG-9.10.11 and CpG-12 was quantitatively higher in cancer tissue DNA than in the normal, and also correlated with the degree of clinical stages（P〈0.05）. Although cervical lesion development was associated with the alteration of methylation ratio of target CpG （0.22）, increased in CIN （0.26）, and highest in fragment at the promoter region of CALCA, i.e. low in cervicitis CSCC（0.36）, significant difference was only found between CSCC and cervicitis（P〈0.05）. Methylation ratios of six CpG sites including CpG-2, CpG-3, CpG-9/CpG-10/CpG-11 and CpG-12 were significantly higher in CSCC than in CIN or cervicitis （P〈0.05）. CONCLUSION： The methylation of CALCA gene promoter was closely associated with the development of cervical cancer in Uighur women, and the alteration in the methylation level of certain CpG sites may become a molecular marker for early diagnosis of cervical carcinogenesis.