OncoTargets and Therapy (Feb 2021)
Combination Therapy with iRGD-antiCD3 and PD-1 Blockade Enhances Antitumor Potency of Cord Blood-Derived T Cells
Abstract
Mei Zhu,1– 3,* Hongmei Wang,1,2,* Shujuan Zhou,4,* Jia Wei,2 Naiqing Ding,2 Jie Shao,2 Lixia Yu,2 Zhenqing Feng,5,6 Baorui Liu1,2 1The Comprehensive Cancer Centre of Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing, Jiangsu, 210008, People’s Republic of China; 2The Comprehensive Cancer Centre of Drum Tower Hospital, Medical School of Nanjing University and Clinical Cancer Institute of Nanjing University, Nanjing, Jiangsu, 210008, People’s Republic of China; 3Department of Oncology, Xuzhou Cancer Hospital, Xuzhou, Jiangsu, 221005, People’s Republic of China; 4The Department of Radiation Oncology, Fudan University Shanghai Cancer Centre, Shanghai, 200032, People’s Republic of China; 5Department of Pathology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People’s Republic of China; 6Key Laboratory of Antibody Technique of Ministry of Health, Nanjing Medical University, Nanjing, Jiangsu, 211166, People’s Republic of China*These authors contributed equally to this workCorrespondence: Zhenqing FengDepartment of Pathology, Nanjing Medical University, 101 Longmian Avenue, Jiangning, Nanjing, Jiangsu, 211166, People’s Republic of ChinaEmail [email protected] LiuThe Comprehensive Cancer Centre of Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, 321 Zhongshan Road, Nanjing, Jiangsu, 210008, People’s Republic of ChinaEmail [email protected]: T cell-redirecting bispecific antibodies (BsAbs) are emerging as a potent cancer therapy that crosslinks tumor cells and T cells by simultaneously binding to tumor-associated antigen and CD3ϵ. However, immune inhibitory molecules can be remarkably upregulated after BsAbs treatment, leading to a suppressive tumor microenvironment and treatment resistance. This can be partially reversed by combination with immune checkpoint inhibitors. In our previous work, we successfully constructed the recombinant protein iRGD-antiCD3 and demonstrated that it promoted antitumor efficacy of transferred T cells by promoting T cell activation and infiltration.Methods: We detected the levels of both PD-1 and PD-L1 as resistance to iRGD-antiCD3 treatment. Using cord blood-derived T cells, we assessed the activation and effects of iRGD-antiCD3 combined with PD-1 as evidenced by activation markers, Th1/Th2-cytokines, and killing capability against tumor cells in vitro. Moreover, to better mimic the physiological characteristics of in vivo solid tumors, we generated 3D spheroids from target cell lines. Spheroids were stained with a Viability/Cytotoxicity Assay Kit and examined by confocal microscopy to study the in vitro antitumor effect of T cells co-administered with combination iRGD-antiCD3 and PD-1 blockade. The mouse peritoneal metastatic gastric tumor model was employed. The synergistic antitumor effect and safety profiles in vivo were evaluated by tumor and body weight of tumor-bearing mice.Results: We found that expression of both PD-1 and PD-L1 were increased as resistance to iRGD-antiCD3 treatment. We found that PD-1 blockade partially restored T cell activation as evidenced by elevated activation markers, Th1-cytokines, and killing capability against tumor cells in vitro. The combination of PD-1 blockade consistently and significantly increased cord blood-derived T cell cytotoxicity against 3D tumor spheroids. In vivo, we observed synergistic antitumor activity without obvious side effects.Conclusion: These results demonstrated that combining iRGD-antiCD3 with PD-1 blockade could further improve antitumor efficacy of T cells, and this strategy holds great potential for the treatment of solid malignancies.Keywords: cord blood-derived T cell, iRGD-antiCD3, PD-1 blockade, combination therapy
