DNA羟化酶TET2失活在结直肠癌发病中的作用及其分子机制研究

Previous studies showed that TET family DNA hydroxylase inactivation is closely related to the tumor occurrence and development. Our former studies have found that in colorectal cancer tissues DNA hydroxylase TET2 protein subcellular localization changed. TET2 deficiency in nuclear with low level of 5–hydroxylmethylcytosine (5hmc) in colorectal cancer cells is closely related. Further study found that the lack of TET2 nuclear expression in clinical samples is associated with distal metastasis of colorectal cancer. These results suggested tumor suppressor gene TET2 function may be associated with metastasis of colorectal cancer.This project proposed to observe DNA hydroxylase TET2 deficiency in nuclear correlated with the clinical pathological characteristics and prognosis of colorectal cancer.In cell biology experiments, we will study the effect of genetic knockout of TET2 in colorectal cancer cells and normal colon epithelial cell lines. We also use molecular biology techniques, such as RNA - sequence to verify target genes of TET2 in colorectal cancer cells. And in nude mice and transfer model, we will study the effects of TET2 on colorectal cancer occurrence and metastasis. This project aims to clarify the DNA hydroxylase TET2 inactivation role in colorectal cancer initiation and its molecular mechanism,which will provide potential molecular markers and drug targets for the treatment of colorectal cancer, diagnosis and prognosis.

既往研究表明，TET家族DNA羟化酶失活与肿瘤发生、发展密切相关。我们前期研究发现，在结直肠癌组织中DNA羟化酶TET2蛋白的亚细胞定位发生改变，同时TET2核表达的缺失与结直肠癌细胞中5-羟甲基胞嘧啶(5hmC)含量的降低密切相关，进一步的研究发现临床样本中TET2核表达的缺失与结直肠癌的远端转移有关，提示我们肿瘤抑制基因TET2的功能可能与结直肠癌的转移相关。本课题在临床组织标本中，观察DNA羟化酶TET2核表达的缺失与结直肠癌临床病理特征及预后的关系；细胞生物学实验中，研究干预TET2表达对结直肠正常上皮细胞株和结直肠癌细胞株生物学行为的影响；同时使用RNA-sequence等分子生物学技术，筛选鉴定结直肠癌细胞中TET2调控的靶基因；并在裸鼠接种和转移模型中，研究TET2对结直肠癌发生、转移的影响。这项研究有望为结直肠癌的治疗、诊断和预后判断提供潜在的分子标记物与药物靶标。

既往研究表明，TET家族DNA羟化酶失活与肿瘤发生、发展密切相关。我们前期研究发现，在结直肠癌组织中DNA羟化酶TET2蛋白的亚细胞定位发生改变，同时TET2核表达的缺失与结直肠癌细胞中5-羟甲基胞嘧啶(5hmC)含量的降低密切相关，进一步的研究发现临床样本中TET2核表达的缺失与结直肠癌的远端转移有关，提示我们肿瘤抑制基因TET2的功能可能与结直肠癌的转移相关。本课题在临床组织标本中，观察DNA羟化酶TET2核表达的缺失与结直肠癌临床病理特征及预后的关系；细胞生物学实验中，研究干预TET2表达对结直肠正常上皮细胞株和结直肠癌细胞株生物学行为的影响研究TET2对结直肠癌发生、转移的影响。本项目结果表明结直肠癌组织中TET2的核表达缺失，并且与肠癌远处转移相关。进一步的细胞实验结果表明，在结直肠癌细胞中TET2蛋白核表达缺失，TET2可以提高细胞内5hmc的水平从而影响细胞的生物学功能。这项研究有望为结直肠癌的治疗、诊断和预后判断提供潜在的分子标记物与药物靶标。