转录因子FOXA2调控乳腺癌细胞上皮间质转化的分子机制研究

To control breast cancer metastasis is a big challenge in the clinical treatment of this malignant tumor. Epithelial-mesenchymal transition (EMT) is considered to play critical roles in the prophase of breast cancer metastasis. It is well known that many genes significantly change in their gene expression during EMT. To study gene regulatory mechanisms of certain transcription factors during breast cancer cell EMT will help us to understand the metastasis of this tumor and to design new therapeutic strategies to treat this disease. Our preliminary data have confirmed that transcription factor FOXA2 is one of the key factors preventing EMT of breast cancer cells. In this proposal, we will continue to focus on the regulatory functions of FOXA2 on gene expression during EMT. We intend to identify co-factors that interact with FOXA2 in breast cell lines MCF-7 (epithelial type) and MDA-MB-231 (mesenchymal type), and test whether the interaction between FOXA2 and its co-factor(s) mediates the stimulation of E-type genes and repression of M-type genes through FOXA2. This hypothesis will be further tested in the EGF-induced EMT model of breast epithelial cell line MCF-10A. We plan to isolate the sub-groups of E-type cells and M-type cells from clinical breast cancer samples by cell sorting. By knocking down FOXA2 levels in E-type cells and elevating FOXA2 levels in M-type cells, we will test whether the levels of FOXA2 in breast cancer cells will affect the tumorigenicity and mobility of different sub-group cells in the nude mouse model of metastasis. We hope that this study will confirm the value of FOXA2 for preventing the EMT of breast cancer cells in clinical therapeutic strategies of breast cancer metastasis treatment.

乳腺癌转移是临床治疗中的一大难题。乳腺癌细胞发生上皮间质转化（EMT）是导致转移的早期事件, 基因表达调控在其中发挥了关键作用。研究特定转录因子调节乳腺癌细胞EMT的分子机理，对阐明肿瘤转移机制和临床治疗中应对乳腺癌转移具有重要意义。前期工作表明，转录因子FOXA2是乳腺癌细胞EMT过程中的关键抑制因子。本项目将以FOXA2为研究对象，运用乳腺癌E型MCF-7细胞和M型MDA-MB-231细胞为EMT对应细胞模型，确认EMT过程中FOXA2的互作蛋白，探讨乳腺癌细胞中FOXA2刺激E型基因和抑制M型基因表达的分子作用机制，并在EGF诱导E型MCF-10A细胞发生EMT过程的细胞模型中加以验证。从乳腺癌细胞株及临床样本中分选获得E型和M型细胞亚群，在裸鼠转移模型中研究FOXA2及互作蛋白表达水平与不同亚群细胞迁移能力之间的对应关系，确立将FOXA2用于抑制乳腺癌细胞EMT过程的临床应用价值。

恶性肿瘤主要特征之一是其能从原发部位向其他组织和器官转移，研究恶性肿瘤转移机制并确认抑制转移的治疗靶点，对肿瘤临床治疗具有重要意义。乳腺癌转移是乳腺癌临床治疗中面临的一大难题。乳腺癌细胞发生上皮间质转化（EMT）是导致其转移的关键早期事件, 基因表达调控在其中发挥了关键作用。研究特定转录因子调节乳腺癌细胞EMT的分子机理，对认识乳腺癌细胞的转移机制并确认抑制靶点具有重要价值。本项目重点研究转录因子FOXA2在乳腺癌细胞EMT过程中的作用机制，运用乳腺癌EMT对应的细胞模型，证明FOXA2是乳腺癌转移的关键抑制因子。通过分析FOXA2的互作蛋白，探讨FOXA2刺激E型基因和抑制M型基因表达的分子作用机制。本项目取得的成果包括：1，FOXA2抑制乳腺癌转移。2，FOXA2的互作蛋白名单。3，FOXP2抑制乳腺癌转移，FOXP2与FOXA2互作参与对EMT相关基因表达调控。相关成果表明了FOXA2和FOXP2在抑制乳腺癌转移中的潜在应用价值，为应对乳腺癌转移难题和明确新的乳腺癌分子分型标志物和治疗靶标提供理论依据。通过开展FOX转录因子家族其他成员与乳腺癌的相关研究，本项目取得的成果还包括：1，FOXA1诱导三阴乳腺癌细胞凋亡的新机制。2，FOXM1促进乳腺癌细胞干性。3，获得了抑制FOXM1的蛋白类抗肿瘤先导药物和核酸适配体。本项目所获成果，深化对FOX家族转录因子参与乳腺癌转移、干性、凋亡等表型调控的认识，确认乳腺癌的新治疗靶点，为乳腺癌临床诊断和治疗提供新思路。相关成果已发表高水平SCI论文（IF>5）2篇，待发表论文4篇，申请并公开专利3项，毕业研究生14名，其中博士3名，硕士11名。项目经费严格按相关规定支出使用，结余经费依照基金委政策，将参照原预算及已在执行中的预算进行支出。