分泌anti-PD-L1及IFNα的间充质干细胞联合治疗小鼠黑色素瘤

Combination therapy for mouse melanoma using mesenchymal stem cells secreting anti-PD-L1 and IFNα

目的:为了提高免疫检查点阻断治疗的疗效,探讨以间充质干细胞(MSC)为载体,anti-PD-L1和IFNα对小鼠黑色素瘤的联合治疗效果。方法:构建重组质粒并生产慢病毒,利用慢病毒感染MSC细胞并获得MSC-anti-PD-L1-Fc和MSCIFNα4-Fc两种细胞系。利用CCK-8细胞增殖实验及OT-Ⅰ小鼠T细胞杀伤实验检测两种细胞系在体外的抗肿瘤活性,ELISA、qPCR、流式细胞术等方法检测两种细胞系体内治疗的药效、分布及抗肿瘤活性。结果:体内和体外实验表明MSC-anti-PD-L1-Fc和MSC-IFNα4-Fc两种细胞系均可显著抑制小鼠黑色素瘤的生长,二者联合治疗可有效提高对小鼠黑色素瘤的肿瘤负荷控制,延长小鼠生存期并促进肿瘤微环境由免疫抑制向免疫促进的转化。结论:利用MSC作为载体的联合免疫治疗是可行的思路,可能是肿瘤免疫治疗的一种新策略。

Objective:To improve therapeutic effect of immune checkpoint blockade,mesenchymal stem cells (MSC) were used as vehicles to investigate the combination effects of anti-PD-L1 and IFNα on mouse melanoma.Methods:Recombinant plasmids were constructed to produce lentivirus. MSCs were infected with these lentiviruses to engineer two cell lines:MSC-anti-PD-L1-Fc and MSC-IFNα4-Fc. In vitro anti-tumor activity was evaluated by CCK-8 assay and OT-Ⅰ T cell killing assay. In vivo therapeutic effects,distribution and anti-tumor activity of MSC cell lines were analyzed by ELISA,qPCR and flow cytometry,etc.Results:MSC-anti-PDL1-Fc and MSC-IFNα4-Fc could significantly inhibit melanoma growth in vitro and in vivo. Combination therapy of two cell lines could effectively reduce melanoma burden,prolong the survival of mice and re-activate the immuno-suppressed tumor microenvironment in mouse melanoma model.Conclusion:Combination therapy using mesenchymal stem cells is a feasible idea and may provide new directions for cancer immunotherapy.