Mcl-1介导的γδ T细胞凋亡调控对神经母细胞瘤的杀伤作用研究

Neuroblastoma (NB) is one of the malignant tumors with poor prognosis in children. The high rate of disease recurrence, metastasis and mortality diminish the efficacy of the treatment by traditional surgery or chemotherapy. Immunotherapy based on γδ T cells’ cytotoxicity against tumors is one of the potential candidates among other emerging immunotherapies such as CAR-T and humanized antibodies. Our preliminary research revealed a pathological augment of γδ T cells in NB patients accompanied with a poor response to PAM, a stimulant specific for γδ T cell proliferation. At same time, the γδ T cells exhibited a less ability for tumor killing with decreased cell survival during expansion by stimulant. Coincidently, multiple pro-survival cytokines were found decrease in the serum of NB patients. Dissection of gene expression of γδ T cells showed that Mcl-1, an anti-apoptotic factor of Bcl-2 family member, decreased in its expression possibly linked to an undermined STAT5 signaling. The aim of this study is to investigate how the cell apoptosis control by Mcl-1 and its upstream signaling regulate the survivability, proliferation as well as tumorcidal effect of γδ T cells. Animal tumor burden and adoptive transfer experiments will be employed for addressing how the survivability of γδ T cells manipulated by Mcl-1 affects its tumor killing in vivo. Data from this study will endow the knowledge and pave the road for immunotherapy against NB using γδ T cells.

神经母细胞瘤（NB）是预后极差的儿童恶性肿瘤之一，传统外科手术和化疗未能解决此疾病高复发、易转移及高死亡率的问题。肿瘤免疫治疗方兴未艾，其中基于γδ T细胞的免疫治疗是一个重要方向。我们前期研究发现NB患者外周血中γδ T 细胞呈现病理性升高，并且γδ T细胞的磷酸抗原扩增效率降低，细胞凋亡增加，而肿瘤杀伤能力降低。同时，患者外周血中多种促生存细胞因子减少，γδ T细胞中抗凋亡基因Mcl-1表达降低，STAT5信号减弱。在此基础上，本研究旨在分析NB患者γδ T细胞增殖、凋亡及肿瘤杀伤能力，研究Mcl-1对γδ T细胞的凋亡调控作用，并探索NB患者γδ T细胞中Mcl-1的表达受到何种上游细胞因子及信号通路调节；进一步通过动物成瘤实验和免疫细胞过继转移技术来理解Mcl-1介导的γδ T细胞凋亡调控对其肿瘤杀伤能力的影响。本研究的结论将为NB的γδ T细胞免疫治疗提供有效实施的理论依据。

神经母细胞瘤（NB）是预后极差的儿童恶性肿瘤之一，传统外科手术和化疗未能解决此疾病高复发、易转移及高死亡率的问题。肿瘤免疫治疗方兴未艾，其中基于γδ T细胞的免疫治疗是一个重要方向。在前期的研究中我们发现NB患者γδT细胞扩增效率低、凋亡增加，肿瘤杀伤能力降低，同时抗凋亡基因Mcl-1表达降低，STAT5信号减弱。本研究旨在提高NB患者γδT细胞的生存活力及肿瘤杀伤能力，同时探究Mcl-1对γδT细胞的凋亡调控作用。结果显示NB患者γδT细胞增殖能力降低、抗肿瘤功能减弱。为了提高NB患者γδT细胞生存力，我们在原有的培养体系中加入IL-15，结果显示，IL-15能够有效提高NB患者γδT细胞体外扩增能力，同时增强其抗凋亡能力。为了进一步探究IL-15增强NB患者γδT细胞抗凋亡能力的潜在机制，研究发现，经IL-15刺激培养的γδT细胞，Mcl-1的表达显著上调，同时发现STAT5、ERK的磷酸化水平增加，以上结果提示Mcl-1参与了γδT细胞的凋亡调控，并且Mcl-1的表达可能与STAT5、ERK的磷酸化水平有关。同时，通过肿瘤杀伤实验进一步证实，IL-15能够有效增强NB患者γδT细胞的杀伤能力。本课题的成果将为神经母细胞瘤的 γδ T 细胞免疫治疗提供新的思路和理论基础，具有重要的理论意义和潜在的应用价值。