瞬时抑制CD46分子增强NK细胞肿瘤免疫治疗作用的研究

As a frequently occurring disease, malignant tumors have a great threat to human health. Immunotherapy has become the latest anti-cancer biological science. Many tumors upregulate expression of CD46 to escape destruction by immune defense. Selected from the expression library of adenovirus type 35 fiber knob mutants, a variant (Ad35K++) that had a higher affinity to CD46 than did the natural Ad35 fiber knob. We have successfully produced recombinant human Ad35K++ protein, and demonstrated that Ad35K++ could up-regulate the cytotoxicity of NK cells by in vitro experiments. On this basis, we want to investigate after Ad35K++ inhibits the expression of CD46, changes of proliferation and apoptosis in tumor cells, and the sensitivity of tumor cells to NK cells. Futhermore, we want to explore whether Ad35K++ induced NK cell function by Notch signaling pathway, and study the molecular mechanisms in animal models. With the enhancement of anti-tumor impact of NK cells, we could explore the potential of NK cells for adaptive immunotherapy.

恶性肿瘤严重危害人类健康。以机体免疫细胞为主体的细胞免疫治疗，以其强大的抗肿瘤作用和较低的毒副作用逐步成为肿瘤治疗研究的新方向。研究显示膜结合性的补体调节蛋白(mCRPs) CD46可使肿瘤细胞逃避机体的免疫防御。人35型腺病毒(Ad35)主要感染表达CD46 的细胞，而突变Ad35纤维突蛋白（Ad35K++）比野生型Ad35K对CD46有更强的亲和力。我们已成功构建和制备了重组人Ad35K++蛋白，并通过体外实验证明Ad35K++蛋白可以促进NK细胞的杀伤功能。拟在此基础上，观察Ad35K++蛋白抑制CD46分子后，肿瘤细胞增殖、凋亡的变化，以及肿瘤细胞对NK细胞杀伤敏感性的改变；同时探讨Ad35K++蛋白通过Notch信号通路诱导NK细胞杀伤功能的分子机制，并在体内动物模型中验证Ad35K++蛋白提高NK细胞抗肿瘤效应，为临床NK细胞过继免疫治疗肿瘤提供新的有效策略。

血液恶性肿瘤严重危害人类健康。近年来，NK细胞介导的抗肿瘤免疫治疗作用日益受到人们的重视，提示以NK细胞为效应细胞联合其他检查点受体阻断将为肿瘤治疗开辟新方向。白血病是一迄今无法治愈的血液系统肿瘤。前期研究表明，CD46活化后能够免疫细胞功能以及细胞因子分泌产生影响。本课题研究了CD46活化对NK细胞抗白血病活性的影响。通过Ad35纤维突蛋（Ad35K++）及活化抗体对NK细胞表明的CD46分子进行活化，使白血病细胞对NK细胞杀伤敏感性发生改变，同时探讨Ad35K++蛋白通过Notch信号通路诱导NK细胞杀伤功能的分子机制，并在体内动物模型中验证Ad35K++蛋白提高NK细胞抗肿瘤效应。Tim-3是一个免疫检查点阻断性分子，Tim-3与其配体结合抑制NK细胞功能，阻断Tim-3有望成为新的免疫治疗手段。多发性骨髓瘤（MM）是一迄今无法治愈的浆细胞肿瘤。我们的实验结果显示MM骨髓及外周血NK细胞高表达Tim-3，MM细胞株及原代MM细胞高表达Tim-3配体，Tim-3阻断显著提高了NK细胞杀伤MM细胞作用。本研究为以NK细胞为核心治疗血液肿瘤奠定基础，为研发靶向新药提供理论基础。