CAR-T细胞肿瘤浸润能力不足是其实体瘤疗效欠佳的主要原因之一。申请者在前期开展靶向肾癌抗原CAIX的CAR-T细胞治疗肾癌研究的基础上提出如下改进策略：1）利用GPI信号结构域将抗VEGFR-2的单链抗体（scFv）锚定于CAR-T细胞表面，利用抗VEGFR-2 scFv对肿瘤血管内皮表面VEGFR-2的识别，使CAR-T细胞靶向聚集于肿瘤部位；2）在CAR-T细胞中过表达肿瘤细胞外基质（ECM）降解酶heparanase（HPSE），通过HPSE对肿瘤ECM的降解作用增强CAR-T细胞的肿瘤浸润能力。二者共同促进靶向CAIX的CAR-T细胞对肾癌的杀伤作用。本研究将通过体外及动物实验证实这种新型CAR-T细胞的肾癌治疗效果。

Adoptive transfer of chimeric antigen receptor (CAR)-redirected T lymphocytes (CAR-T cells) has had less striking therapeutic effects in solid tumors than in lymphoid malignancies. One of the reasons is limited infiltrating ability of CAR-T cells into tumors. We confirmed the therapeutic effects of CAR-T cells targeting CAIX for renal carcinoma previously. We will develop novel strategies to enhance the therapeutic effects of CAIX-CAR-T cells in this study: 1) direct CAR-T cells to accumulate at tumor site through the binding of anti-VEGFR-2 scFv anchored on CAR-T cells by Glycosyl-phosphatidylinositol (GPI) to VEGFR-2 over expressed on endothelial cells of tumor vessels; 2) enhance the ability of CAR-T cells to penetrate stroma-rich tumor tissue through heparanase (HPSE) over expressed in CAR-T cells, which degrades heparin sulfate proteoglycans, the main components of extracellular matrix (ECM). The two strategies will promote the killing effects of CAIX-CAR-T cells to renal carcinoma cells synergistically. We will confirm the therapeutic efficacy of the novel CAR-T cells to renal carcinoma by in vitro and in vivo experiments.