Nodal疫苗对恶性黑色素瘤的防治作用及机制研究

Malignant melanoma (MM) is insensitive to chemoradiotherapy and easy to transfer resulting in short overall survival time of patients. It’s looming ahead to find new therapeutic method such as immunotherapy to suppress cancer metastasis and improve overall survival. Nodal is a member of TGF-β family and plays an important role in epithelial-mesenchymal transition (EMT) and maintaining the immature status of embryonic myeloid-derived suppressor cells (MDSC). MDSC can induce immunosuppression in cancer patient. Our publications have pointed that Nodal re-express highly in many kinds of cancer and it promotes cancer malignant development by taking part in EMT. We proposed hypothesis on this basis that Nodal vaccine could inhibit cancer metastasis and improve survival by stimulating immune response and blocking the function of Nodal in the body to inhibit the EMT and promote differentiation of MDSC in tumor. Firstly, we will prepare Nodal vaccine on the basis of previous work that we have recombined human Nodal protein. Moreover, we will also determine the role and possible mechanism of Nodal vaccine in the prevention and treatment of malignant melanoma by inhibiting the growth and metastasis of tumor and extending overall survival time at different kind of level. Therefore our results will contribute to the prevention and treatment of malignant melanoma by the method of immunological therapy.

恶性黑色素瘤易转移，患者生存预后差，因其对常规放化疗敏感性低，使得肿瘤免疫疗法成为值得尝试的策略。Nodal是TGFβ家族成员，参与了胚胎期的上皮间质转化（EMT）和髓性抑制性细胞（MDSC）未成熟状态的维持。我们前期研究发现：Nodal在多种肿瘤组织中重新特异性高表达，通过参与EMT，促进肿瘤恶性进展，提示Nodal可作为肿瘤治疗的靶点。近期预实验结果发现Nodal可升高荷瘤鼠骨髓组织中MDSC数目比例。据以上内容我们提出假设：使用Nodal疫苗激发机体自身免疫反应，封闭了Nodal的作用可抑制肿瘤的EMT并促进MDSC的分化成熟，降低肿瘤转移。本课题拟在前期工作基础上制备Nodal蛋白疫苗，研究其对恶性黑色素瘤的生长、转移及生存预后的防治作用，并从Nodal及其抗体对肿瘤EMT及MDSC的作用两个方面解析Nodal疫苗阻抑肿瘤恶性进展的内在机制，为恶性黑色素瘤的免疫治疗提供新的理论支持

恶性黑色素瘤易转移，患者生存预后差，肿瘤的免疫治疗可有效控制肿瘤生长和转移。 我们构建了在肿瘤组织中高表达的nodal蛋白，通过原核表达系统制备了高纯度的nodal重组蛋白，加入免疫佐剂制成nodal蛋白疫苗。研究发现nodal疫苗可以显著提高B16移植瘤小鼠的生存期， 阻抑B16黑色素瘤的肺转移、肝转移和淋巴结转移。Nodal疫苗对小鼠的皮毛光亮度、一般行为、体重、反应性以及重要脏器的组织变化、血液学和生化学指标均无显著影响，提示本研究制备的Nodal疫苗具有一定的安全性。Nodal疫苗可以激发机体产生大量高效价、以IgG2b为主的特异性Nodal抗体，可阻抑Nodal参与由EMT引起的肿瘤恶性进展，并且降低机体MDSC的含量，削弱MDSC介导的免疫抑制作用，从而使机体产生积极的免疫反应而抑制肿瘤的转移，为恶性黑色素瘤的免疫治疗提供新的思路。