vGPCR-IL-4Rα双靶向抑制卡波氏肉瘤病毒相关肿瘤的作用研究

Due to poor prognosis of several maligancies caused by Kaposi's sarcoma Herpesvirus (KSHV) and tight relation to mortality and morbidity of AIDS patient, it is urgent to seek novel treatment strategy against these cancers. Many clincial data has shown that KSHV-associated cancer patients are usually immune suppression, and both latency and lytic replication phases are crucial for KSHV's capacity to induce and maintain tumorigenesis. Chimeric antigen receptor (CAR) expressing T cells have the ability to specifically recognize and target tumor expressing certain antigen, while cytotoxin has the advantage to kill tumor cell directly. We and other colleagues have demonstrated that IL-4Rα (a host membrane receptor) and vGPCR (a virus encoded membrane protein) are overexpressed during KSHV latency and lytic replication infection, individually. However, it remains unclear whether these two proteins could be used as target to eradicate KSHV-associated cancers. Based on our preliminary work, in this proposal we will screen Fabs and poly-peptides phage display libraries to obtain Fabs and poly-peptides binding to IL4Rα and vGPCR individually, and obtain their CAR-T and chimeric cytotoxin followed by evaluating their KSHV-associated cancer targeting effects and potential mechanisms in different combinations. This study will strengthen our understanding of the role of KSHV lytic and latency replication in tumorigenesis, and provide new targets and strategies against KSHV-associated cancers.

卡波氏肉瘤病毒(KSHV)引发的多种恶性肿瘤因与艾滋病患者死亡密切相关且预后差，急需寻找新的有效治疗方案。大量临床数据表明KSHV肿瘤患者普遍具有免疫力低下特征，及潜伏-裂解并存感染对KSHV致瘤和维持至关重要。嵌合抗原受体CAR-T细胞过继免疫治疗可赋予免疫细胞对特定肿瘤抗原的靶向杀伤，而嵌合毒素具有直接杀伤靶向细胞的优势，均为目前国内外研究热点。我们及同行已发现KSHV潜伏和裂解期分别上调表达宿主表面受体IL-4Rα和自身编码膜蛋白vGPCR，但二者是否可作为靶点用于消除KSHV肿瘤尚未完全清楚。本课题拟在前期工作的基础上，通过分别筛选IL-4Rα和vGPCR特异高效识别的抗体和肽段，同时构建相应CAR分子和嵌合毒素，在体内外探究其单一或不同组合方式对KSHV肿瘤细胞的靶向杀伤作用和凋亡机制。本项目的实施将有助于加深对KSHV致瘤机制的认识，并为KSHV肿瘤靶向治疗提供依据和策略。

卡波氏肉瘤病毒(KSHV)可引发多种恶性肿瘤，与艾滋病患者死亡密切相关且预后差，需要科研提供新的有效治疗方案。本课题针对KSHV潜伏和裂解期分别上调表达的宿主表面受体IL-4Rα和自身编码膜蛋白vGPCR，取得以下进展：1）筛选获得16株能够与vGPCR膜外端特异结合的单克隆抗体、2个特异靶向IL-4Ra的CAR 载体，发现IL-4R特异CAR T细胞对肿瘤细胞有特异抑制作用；2）获得1条特异靶向vGPCR和1条特异靶向IL-4Rα的多肽，发现这两条多肽嵌合裂解毒素对KSHV阳性肿瘤在体内外的具有强靶向杀伤作用及影响KSHV病毒裂解复制的影响，共同靶向具有协同作用；3）发现B7-H3 CAR T细胞、植物天然小分子单体 Cambogin以及纳米银颗粒nAg在体内外均具有特异抑制KSHV相关肿瘤生长的能力。本项目的实施从理论上证明了可在KSHV肿瘤相关治疗时同时靶向KSHV不同时期，并为KSHV肿瘤靶向治疗提供新的治疗思路和材料。