双亲和性适配体靶向脂质体介导的T细胞免疫治疗

T cell immunotherapy mediated by dual-affinity aptamer targeted liposome

将免疫细胞重定向至肿瘤部位并增强抗肿瘤免疫反应是一种有前景的癌症治疗策略。AS1411适配体对高表达核仁素的恶性肿瘤有高亲和结合力,细胞毒性T淋巴细胞相关蛋白4(cytotoxic T-lymphocyte-associated protein 4,CTLA-4)适配体可特异性结合T细胞表达的免疫检查点CTLA-4。本研究基于AS1411适配体和CTLA-4适配体构建了一种可同时靶向肿瘤细胞和T细胞的双亲和性适配体靶向脂质体(dual-affinity aptamer targeted liposome,Dat.Lipo),并在细胞水平研究其促T细胞免疫治疗效果。将适配体修饰上胆固醇后,用滴入法制备Dat.Lipo;用成像系统检测其T细胞重定向作用,CCK8(cell counting kit-8)评价其促T细胞免疫治疗作用,用肿瘤球评价其促T细胞渗透作用。结果表明,与只负载一种适配体的脂质体相比,Dat.Lipo可有效促进T细胞重定向至肿瘤细胞;对MCF-7和HepG2细胞具有良好的促免疫治疗作用,且呈浓度依赖性,具有良好的生物安全性;Dat.Lipo还能促进T细胞渗透到肿瘤球内部,在不同维度增强T细胞免疫治疗作用。综上,Dat.Lipo可利用适配体对靶标的高亲和性将T细胞重定向至肿瘤细胞,增强免疫疗法效果,在肿瘤治疗方面具有一定的应用前景。本研究获得了湖南省肿瘤医院中南大学湘雅医学院附属肿瘤医院审查委员会的伦理批准。

Redirecting immune cells to the tumor cells and enhancing its anti-tumor immune response is a very promising cancer treatment strategy.AS1411 aptamers have high affinity for malignant tumors with high nucleolin expression,and cytotoxic T lymphocyte associated protein 4(CTLA-4)aptamers can specifically bind to CTLA-4,which is expressed by T cells.In this study,a dual-affinity aptamer targeted liposome(Dat.Lipo)was constructed based on AS1411 aptamer and CTLA-4 aptamer,and its immunotherapeutic effect on T cells was studied.After the aptamer was modified with cholesterol,Dat.Lipo was prepared by instillation method;its effect of redirecting T cells was determined by confocal micrographs;its T cell immunotherapy effect was evaluated by cell counting kit-8(CCK8)and T cell penetration was evaluated by tumor spheroids.The results showed that compared with liposomes loaded with one type aptamer,Dat.Lipo could effectively promote the redirection of T cells to tumor cells;Dat.Lipo had good biosafety and immunotherapeutic effect on MCF-7 and HepG2 cells in a concentration-dependent manner;Dat.Lipo could also promote T cells to infiltrate into the tumor spheroids and enhance the immunotherapy effect of T cells in different dimensions.In summary,Dat.Lipo can use the high affinity of aptamers to redirect T cells to tumor cells,enhance the effect of immunotherapy,and has a promising application prospect in tumor therapy.This study was approved by the Examination Committee of Cancer Hospital of Xiangya School of Medicine,Central South University,Hunan Cancer Hospital.