新型microRNA(mir-n5)通过降低CREBBP的表达抑制前列腺癌转移的机制研究

Prostate Cancer (PCa) is the most prevalent malignancy in the male urogenital system worldwide. Patients with early stage PCa often have a relatively long life expectancy; however, patients with advanced PCa often develop metastasis and have a limited life expectancy. Thus, it is a vital question to identify the possible mechanism involved in the development of metastasis in PCa patients. We have performed RNA-seq in the cancer tissue and adjacent tissue from in a total of 65 patients. We discovered several novel microRNAs which were not previously reported. We have performed Northern blot assay and identified that mir-n5 to be low-expressed in PCa cells, PCa tissue and in the serum of patients with PCa. Preliminary data showed that low expression of mir-n5 is associated with enhanced migration and invasion in PCa cell lines. Preliminary Bioinformatics Analysis revealed that CREBBP is the target gene for mir-n5, which was later confirmed by subsequent fluorescein reporter assay. Based on these data, we aimed to investigate the mechanism of mir-n5 in inhibiting prostate cancer metastasis by decreasing CREBBP expression. We will also investigate the mechanism involved in the lower expression of mir-n5 in PCa tissue and serum of PCa patients. Hopefully, this study may shed some light on how mir-n5 influences CREBBP and further influence the metastasis of PCa and finally provide a potential molecular therapeutic target.

前列腺癌是男性泌尿生殖系统最常见的恶性肿瘤，早期前列腺癌预后较好，但晚期出现转移后，患者极为痛苦，预后很差。因此研究前列腺癌的晚期转移机制及其治疗靶点是提高前列腺癌诊疗的关键问题。前期我们对65对中国前列腺癌和癌旁组织进行高通量测序，发现并通过Northern blot验证了多个前列腺癌相关的、未见报道的新型micro RNA。经过筛选，mir-n5 在前列腺癌患者癌组织、血清中、在多种前列腺癌细胞系中都显著低表达；细胞系研究证实mir-n5低表达可促进肿瘤侵袭和转移；生物信息学分析提示、报告基因检测初步证实CREBBP是mir-n5的靶基因。本课题研究拟基于当前研究结果，从多层面探究mir-n5通过抑制CREBBP表达，抑制前列腺癌转移和进展的机制；研究前列腺癌组织、血清中出现mir-n5低表达的机制。加深对前列腺癌发病和转移机制的认识，为晚期前列腺癌的治疗提供分子靶点。

研究人员通过对65例前列腺癌组织及配对癌旁组织进行测序，并采用MIREAP程序进行分析。miR-N5可抑制在克隆形成及迁移能力。我们通过信息生物学分析出了miR-N5的靶基因。靶基因的下游基因通过TCGA数据库及MSKCC数据库进行分析并采用CHIP方式进行了验证。通过研究，我们确认了一个新型的microRNA，miR-N5与前列腺癌存在相关性。在前列腺癌组织中、前列腺癌患者的血液中，miR-N5均为低表达。敲除miR-N5可以增强前列腺癌细胞系在体外的转移和侵袭能力。miR-N5可以特异性的靶向CREBBP 3’-UTR区域，并可以抑制CREBBP的表达。抑制CREBBP的表达可以调节EGFR、β-catenin、CDH1的启动子H3K56 乙酰化。本研究提示miR-N5可通过组蛋白乙酰化抑制前列腺癌转移。