DNA结合抑制物2(ID2)在乳腺癌发生发展中的功能和机制研究

Breast cancer is a type of malignant cancer which occurs as a result of mutations, abnormal differentiation and proliferation of mammary cells. ID2 (inhibitor of DNA binding 2) is known as a member of the bHLH transcription factors family, and serves as a negative modulator in genes transcription. However, there is less lecture to reveal the role of ID2 in breast cancer tumorigenesis. Our preliminary data provided evidences that ID2 gene was frequently up-regulated in breast tumors and might play a crucial role in mammary gland development and tumorigenesis. In this study, we plan to determine the multiple phenotypes of ID2 genes via using the three-dimensional (3D) basement membrane culture technique to mimic the mammary gland development. In addition, RNA sequencing & bioinformatics analysis will be utilized to explore the downstream pathways of ID2 gene. Furthermore, we will investigate the molecular mechanism of ID2 and validate its downstream pathways in mammary tumorigenesis and cancer development via in vitro and in vivo experiments. Finally, we will evaluate the prognosis values of ID2 and its targeted molecules among the patients with breast cancer. In conclusion, all of the experiments proposed in this project have relevance to mammary tumorigenesis through careful examination of the biological role of ID2 in mammary cells with the goal for in-depth understanding the molecular progression of breast cancer.

乳腺癌通常起源于乳腺细胞的分化异常、无序生长和恶性转化。ID2基因编码的蛋白是一种具有负性转录调控功能的bHLH转录因子；然而，迄今对ID2在乳腺癌发生发展中的角色仍知之甚少。我们的预实验结果提示ID2在乳腺癌中异常升高，并且在乳腺细胞恶性转化中起重要作用。但是，其作用机制还有待进一步探讨。本课题拟以乳腺细胞分化异常导致癌变为切入点，深入研究ID2在乳腺肿瘤发生中的多重角色：利用三维培养技术检测ID2在乳腺细胞分化和恶性转化中的功能；结合RNA测序技术来解析ID2的下游信号通路；从分子、细胞、以及动物等多角度来验证ID2与其下游通路的在肿瘤发生、发展中的重要作用；最后分析ID2及其下游通路靶分子对乳腺癌的临床预后价值。本研究将阐释ID2及其下游调控信号通路与乳腺癌发生发展的内在联系，最终为ID2基因作为一个潜在乳腺癌标靶的开发奠定基础。

乳腺癌是女性最常见的恶性肿瘤之一，研究发现乳腺肿瘤中大量存在低分化的肿瘤细胞，这些肿瘤细胞具有快速自我复制的特征，但丧失了终末分化能力，具有近似上皮细胞的不成熟形态，导管或者腺泡结构基本消失。乳腺细胞的分化是一个多步骤、多阶段、多因子参与的复杂过程, 细胞的分化障碍涉及了一批关键基因的转录和调控，是乳腺癌发生的启动因素。乳腺肿瘤癌症基因组图谱（TCGA）的预测数据提示，细胞分化相关的DNA结合抑制物2 (inhibitor of DNA binding 2, ID2) 基因参与了乳腺癌的调控网络，可能是促进乳腺肿瘤发生和发展的关键基因之一。本课题主要围绕ID2基因对于乳腺细胞分化和恶性转化的调控机制，寻找ID2特异性的结合转录因子和下游靶基因，揭示ID2基因在乳腺癌中的功能和作用机制，并探讨ID2基因作为潜在生物靶点的可能性。研究主要内容：利用乳腺细胞体外三维培养技术研究ID2基因在乳腺细胞分化和恶性转化中的功能；结合利用RNA深度测序技术来分析ID2基因的下游信号通路和调控机制；利用荧光报告基因、免疫共沉淀、CHIP和CHIP-seq等技术来确定ID2基因所调控的bHLH转录因子以及下游靶基因；利用组织芯片阵列验证ID2基因表达及其下游调控信号通路与乳腺临床信息的关联性，并期望建立相关的乳腺癌预后预测模型。