miR-454诱导人乳腺癌细胞增殖的分子机制

项目名称： miR-454诱导人乳腺癌细胞增殖的分子机制

项目编号： No.81201546

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 肿瘤学1

项目作者： 刘祥厦

作者单位： 中山大学

项目金额： 23万元

中文摘要： 前期采用MicroRNA芯片技术，我们发现miR-454在乳腺癌组织中表达明显增高并与乳腺癌恶性程度正相关。进一步预实验结果显示miR-454可通过促进细胞G1/S周期转换而诱导细胞增殖。生物信息学及生物学实验结果表明miR-454可直接抑制PTEN表达，增强AKT激酶活性，下调FOXO1的转录活性，从而调控细胞增殖，但具体机制尚待阐明。本项目将以过表达或抑制miR-454的细胞为模型，通过免疫荧光染色、原位杂交及荧光素酶报告基因分析等方法,研究miR-454促进细胞增殖的分子机制,探讨miR-454下调PTEN/激活AKT激酶活性/抑制FOXO1转录活性的信号通路的分子机制。并通过在体内肿瘤动物模型确定miR-454具有诱导肿瘤生长的功能。本研究将为miR-454通过直接调控PTEN/AKT/FOXO1信号通路而导致肿瘤发生发展的科学假设提供证据，并为乳腺癌的诊断治疗提供新的分子靶点。

中文关键词： 乳腺癌；miRNA；miR-495；miR-892b；增殖

英文摘要： Previously, we identified that miR-454 was significantly overexpressed in breast cancer tissues compared to normal breast tissues, using a microRNA chip assay. The expression levels of miR-454 also strongly correlated with the clinical stage of breast cancer. Furthermore, our preliminary data showed that miR-454 induced the proliferation of breast cancer cells via promoting G1/S transitional entry. Moreover, integration of the results of bioinformatic analysis and biological experiments revealed that miR-454 downregulated the tumor suppressor PTEN by directly targeting its 3` untranslated region (3`-UTR) to enhance Akt kinase activity and repress the transcriptional activity of FOXO1, resulting in a pro-proliferative effect in breast cancer cells. These results suggest that miR-454 plays an important role in breast cancer tumorigenesis. Hence, in the current project, we aim to employ immuno-fluorence staining, miRNA in situ hybridization and luciferase reporter assays in both in vitro and in vivo systems and use clinical samples to further investigate the mechanism by which miR-454 induces proliferation, in order to provide new biomarkers and targets for the diagnosis and treatment of breast cancer.

英文关键词： Breast Cancer；miRNA；miR-495；miR-892b；Proliferation