miR-33a启动子甲基化在前列腺癌骨转移中的作用及机制研究

Bone metastasis is a common complication of advanced prostate cancer and seriously affects the quality of life of patients. Our previous study found that the expression of miR-33a in prostate cancer was significantly lower than that in primary tumor. Overexpression of miR-33a in prostate cancer cell lines could inhibit its proliferation, migration, invasion and EMT. In addition, we used DNA methylation inhibitor (5-Aza-d C) to treat prostate cancer bone metastatic cell lines, found that miR-33a gene promoter methylation significantly reduced, and miR-33a expression was significantly increased. Therefore, it is speculated that hypermethylation of the miR-33a promoter in the prostate may be involved in the process of bone metastasis of prostate cancer. On the basis of this, the methylation status of human prostate cancer and its corresponding bone metastases will detect by methylation-specific PCR. Furthermore,the clinical relevance and prognostic value of methylation status of miR-33a promoter and prostate cancer bone metastasis will be analyzed. Meanwhile, the effects of miR-33a and its downstream target genes on bone metastasis of prostate cancer were further explored in cell and animal models.

骨转移是晚期前列腺癌的常见并发症，严重影响患者生活质量。课题组前期通过microRNA基因芯片和RT-PCR证实miR-33a-5p在前列腺癌骨转移灶中的表达较原发肿瘤中明显下调, 在前列腺癌细胞系中高表达miR-33a能抑制其增殖、迁移、侵袭及EMT。另外，我们采用DNA甲基化抑制剂（5-Aza-d C）处理前列腺癌骨转移细胞系后, 发现miR-33a基因的启动子甲基化程度显著降低，且miR-33a表达明显上调。因此，推测在前列腺中miR-33a启动子高甲基化可能参与前列腺癌骨转移过程。本项目拟在此基础上，通过甲基化特异性PCR技术对人前列腺癌原发灶及其对应骨转移灶的DNA甲基化状态进行检测，分析miR-33a启动子甲基化状态与前列腺癌骨转移的临床相关性和预后判断价值。同时, 在细胞和动物模型中进一步深入探讨miR-33a及其下游靶基因对前列腺癌骨转移的影响。

骨转移是晚期前列腺癌（PCa）的常见并发症，严重影响患者生活质量。目前，针对前列腺癌骨转移的治疗多为姑息性治疗，总体治疗效果并不尽如人意。因此，阐明前列腺癌骨转移的分子机制具有十分重要的意义，为前列腺癌骨转移的早期诊断和治疗提供新的思路和方法。本项目前期通过microRNA基因芯片发现miR-33a低表达与前列腺癌骨转移相关, 高表达miR-33a抑制前列腺癌骨转移细胞迁移、侵袭及EMT。另外，DNA甲基化抑制剂（5-AZA）上调miR-33a表达。因此，推测在前列腺中miR-33a启动子高甲基化可能参与前列腺癌骨转移过程。本项目拟在此基础上，通过临床病理研究，探讨miR-33a与 PCa 临床病理特征的相关性，同时探讨miR-33a基因启动子甲基化与PCa骨转移的相关性；应用生物信息学分析、基因转染、干扰及双荧光素酶报告等技术，结合细胞功能实验，进一步探究低表达的miR-33a 靶向SATB2促进PCa骨转移的分子机制；利用骨转移动物模型进一步验证miR-33a对PCa骨转移的影响。结果表明，miR-33a低表达与PCa骨转移、PSA水平及Gleason评分等临床病理特征相关，且miR-33a基因启动子甲基化状态与PCa的骨转移相关。miR-33a通过靶向SATB2调控骨转移性前列腺癌PC-3细胞迁移、侵袭及EMT。进一步的骨转移动物模型实验证明，过表达miR-33a在体内动物模型抑制了PCa的骨转移。通过以上研究，深入阐明miR-33a参与PCa骨转移的分子机制，为PCa骨转移的防治提供理论依据和治疗靶点。