尿液cfDNA甲基化与羟甲基化修饰在膀胱癌发生进展中的动态分析及功能研究

DNA表观遗传修饰的动态失衡与肿瘤发生进展的密切关系逐渐引起重视，探究基因组5mC与5hmC在膀胱癌中的动态分布特征对开发膀胱癌无创性早期诊断及复发监测技术意义重大。目前全基因组单碱基分辨率的表观测序主要依赖亚硫酸氢盐及TAB修饰，存在DNA降解严重及成本过高的难题。本课题组前期通过开发不依赖亚硫酸氢盐的5mC和5hmC测序技术使解析膀胱癌尿液cfDNA表观修饰图谱成为可能。我们发现膀胱癌患者尿液中DNA甲基化和羟甲基化变化明显，提示尿液cfDNA甲基化与羟甲基化修饰的动态失衡可能与膀胱癌密切相关。本项目拟通过不依赖亚硫酸氢盐的5mC和5hmC测序技术对膀胱癌不同阶段患者尿液cfDNA甲基化及羟甲基化进行图谱化及精确定位，寻找生物标志物，用于膀胱癌的早期诊断和复发监测；同时通过对表观遗传修饰差异基因的肿瘤表型及功能研究，探索膀胱癌发生发展的驱动因素。

The close relationship between the dynamic imbalance of DNA epigenetic modification and tumor progression has gradually attracted attention. It is of great significance to explore the dynamic distribution characteristics of genome 5mC and 5hmC in bladder cancer process for the development of noninvasive early diagnosis and recurrence monitoring technology of bladder cancer. At present, the whole genome single base resolution table sequencing technology mainly relies on bisulfite and TAB modification, which has the problems of serious DNA degradation and high cost. Our research group made it possible to analyze the apparent modification map of cfDNA in bladder cancer urine by developing 5mC and 5hmC sequencing technologies that do not rely on bisulfite. We found significant changes in DNA methylation and hydroxymethylation in urine of bladder cancer patients, suggesting that the dynamic imbalance between cfDNA methylation and hydroxymethylation modification in urine may be closely related to the development of bladder cancer. This project intends to map and accurately locate the methylation and hydroxymethylation modification of cfDNA in urine of patients with bladder cancer at different stages by 5mC and 5hmC sequencing technologies that do not rely on bisulfite to find biomarkers at epigenetic level for early diagnosis and recurrence monitoring of bladder cancer. Meanwhile, the driving factors of bladder cancer development were explored by studying the tumor phenotype and function of epigenetic modified differential genes.