TEM8对乳腺癌发展的调控机制及其临床意义研究

Breast cancer has become the No.1 cancer killer threat to women's health. Cancer stem cells are the cause of tumor metastasis, tumor recurrence and drug resistance. Defining the molecular mechanisms of cancer stem cell regulation to identify effective therapeutic targets is the key to the treatment of breast cancer, especially triple negative breast cancer. We found that TEM8 protein expression is positively correlated with the malignancy of breast cancer, and TEM8 is highly expression in cancer stem cell population; inhibition of TEM8 expression in triple negative breast cancer cells can significantly inhibit cell proliferation and invasion; TEM8 overexpression can significantly promote the formation of blood vessels Mimicry, which is regulated by the ubiquitination process. We hypothesized that TEM8 inhibition will be effective in targeting tumor stem cell populations and tumor angiogenesis, thereby inhibiting breast cancer, especially triple-negative breast cancer metastasis and recurrence. The aim of this project is to elucidate the regulation mechanisms of TEM8 on breast cancer stem cells and angiogenesis utilizing siRNA library, gene expression profile analysis and mouse model. It is expected that the inhibition of TEM8 combined with traditional therapies will inhibit breast cancer growth and metastasis. Furthermore, we will explore the clinical significance of TEM8 in the early diagnosisand targeted therapy of breast cancer. These studies will provide novel strategies for diagnosis and therapy of advanced breast cancer.

乳腺癌已经成为威胁女性健康的头号癌症杀手。肿瘤干细胞是导致肿瘤转移、复发及耐药性产生的根源。解析肿瘤干细胞调控分子机制从而找出有效的治疗靶点是治疗乳腺癌尤其是三阴性乳腺癌的关键。我们发现TEM8蛋白表达随乳腺癌恶性程度的增加而增加，并在肿瘤干细胞群体中高表达；抑制三阴性乳腺肿瘤细胞中TEM8表达能够显著抑制细胞的增殖及侵袭；TEM8过表达能够显著促进肿瘤细胞血管拟态生成，并受到泛素化过程调控。我们推测，靶向TEM8的治疗将会有效地靶向肿瘤干细胞群体以及血管再生，从而抑制乳腺癌尤其是三阴性乳腺癌的转移和复发。本项目旨在利用siRNA文库、基因表达谱分析以及小鼠模型等手段，阐明TEM8对乳腺肿瘤干细胞及血管再生的影响及其上下游调控机制，期望通过靶向TEM8或其关键调控节点分子联合传统治疗来抑制乳腺癌的生长和转移；进一步探讨TEM8在乳腺癌诊疗中的临床意义。本研究将为恶性乳腺癌提供新的诊疗策略。

肿瘤干细胞是导致肿瘤转移、复发及耐药的重要因素。解析肿瘤干细胞调控分子机制从而找出有效的治疗靶点是治疗乳腺癌尤其是三阴性乳腺癌的关键。我们通过对三阴性乳腺癌患者癌组织进行转录组测序及生物信息学分析，发现TEM8高表达于三阴性乳腺癌细胞中，是联系乳腺肿瘤细胞干性与血管拟态形成的关键因子。TEM8的高表达可以显著促进乳腺肿瘤干细胞血管拟态形成，从而促进肿瘤发生发展。分子机制研究揭示，TEM8主要通过激活下游RhoC-ROCK1-SMAD5通路来促进肿瘤细胞干性和血管拟态形成。使用病人来源异种移植瘤（PDX）小鼠模型，我们利用小鼠实验发现ROCK1抑制剂与化疗药物联合治疗策略可达到更佳的三阴性乳腺癌治疗效果。此外，我们的研究还发现雌激素受体ERα转录激活的E3泛素连接酶ASB10是调控TEM8蛋白泛素化修饰与降解的重要因素，初步揭示了三阴性乳腺癌细胞高表达TEM8蛋白的分子机制（Nature Communications 2021）。同时，我们通过对临床样本等相关数据分析发现，乳腺肿瘤干细胞标志物ALDH1A1依赖于其酶活性促进乳腺肿瘤干细胞自我更新和免疫抑制微环境形成（Cancer Research 2021）；发现三阴性乳腺肿瘤干细胞高表达IL1R2，通过其胞内段结构域抑制BMI1蛋白的降解，促进了乳腺肿瘤干细胞的自我更新和耐药（Advanced Science 2020）；三阴性乳腺癌细胞高表达MSN，通过形成MSN-NONO复合体激活CREB通路，促进乳腺肿瘤干细胞的自我更新（Science Advances 2020）；UCP1低表达于三阴性乳腺癌，通过糖酵解通路关键酶FBP1抑制ALDH+乳腺肿瘤干细胞（Cell Biology Toxicology 2020）。这些研究将引导我们针对关键的调控节点开发各种靶向乳腺肿瘤干细胞的潜在药物，为乳腺癌的治疗提供潜在的治疗靶点和治疗策略。在本项目的资助下，申请人以通讯作者身份发表了十一篇SCI论文，申请了两项专利，培养了一名出站博士后和四名博士研究生。