携带Decorin的溶瘤腺病毒联合靶向CAIX的CAR-T细胞协同抗肾癌研究

Chimeric antigen receptor T-cell (CAR-T) therapy gets a great success in treating blood tumor; however, the treatment for solid tumor has proved far less successful. The major reasons are focused on the limited infiltrating ability of CAR-T cells into tumor mass and the tumor immunosuppression microenvironment. Our previous research indicated that the oncolytic adenovirus expressing decorin changed the structure of extracellular matrix (ECM), improved the permeability of renal cancer tissue, and attenuated the TGF-β signal in the tumor microenvironment. We also constructed a humanized CAR-T targeted for CAIX and identified the CAIX CAR-T is an effective treatment of renal carcinoma in vitro and in vivo. In this study, we will develop the antitumor activity of oncolytic adenovirus OAV-Decorin combinated with CAIX specific CAR-T cells for renal cancer cells. The aim is to recruit CAR-T to tumor site through OAV directly lysising tumor and releasing tumor antigen. On the other hand, OAV-Decorin enhances the permeability of tumor tissues, attenuates the TGF- beta tumor immunosuppressive signal, so that CAR-T is more infiltrated into the tumor tissue and plays a long-lasting anti-tumor avtivity. This study will confirm this combination strategy in vitro and in vivo.

CAR-T治疗血液肿瘤取得巨大成功，但对实体瘤疗效不佳，主要原因在于CAR-T浸润肿瘤能力不足以及肿瘤免疫微环境对其抑制作用。申请者完成2013年NSFC时发现，携带Decorin的溶瘤腺病毒（OAV-Decorin）能改变肾癌组织ECM结构，提高肾癌组织通透性，且可削弱肿瘤微环境中的TGF-β免疫抑制信号。申请者前期构建了靶向肾癌特异性抗原CAIX的人源化CAR-T，体外及皮下移植瘤注射实验证明其杀伤肾癌作用。本项目拟开展OAV-Decorin联合靶向CAIX的CAR-T协同抗肾癌研究，旨在一方面通过OAV裂解肿瘤细胞，释放出肿瘤抗原，招募CAR-T至肿瘤部位；另一方面OAV介导的Decorin提高肿瘤组织通透性，同时削弱TGF-β免疫抑制信号，使得更多CAR-T浸润至肿瘤，增强其抗肿瘤功能。本研究将通过体外及动物实验证实这种联合策略治疗肾癌效果及其机制。

尽管嵌合抗原受体T细胞(CAR-T)疗法已成功治疗恶性血液病，但对实体瘤的疗效较差。主要原因是免疫微环境限制CAR-T细胞在肿瘤中的浸润和增殖。溶瘤病毒疗法已成为增强抗肿瘤免疫应答的新型免疫原性疗法。本项目中，我们将携带Decorin的溶瘤腺病毒与靶向碳酸酐酶IX (CAIX)的CAR-T结合，对肾癌细胞发挥抗肿瘤活性。我们发现OAV-Decorin联合CAIX-CAR-T可显著降低肿瘤负荷，通过抑制胶原纤维分布改变细胞外基质(ECM)的组成，降低肿瘤细胞TGF-β的表达，增强IFN-γ分泌，获得更高数量的CAR-T细胞。联合治疗方式延长了小鼠的生存期，瘤内注射OAV-Decorin可激活荷瘤免疫能力小鼠的炎症免疫状态，导致肿瘤消退。这些数据支持进一步研究OAV-Decorin和CAIX-CAR-T细胞在实体瘤中的联合应用。