Journal Article

BiTE‐Secreting CAR‐γδT as a Dual Targeting Strategy for the Treatment of Solid Tumors

Tsai, Wan‐Chen, Chiang, Yu‐Ting, Lin, Fang‐Yu, Wu, Chung‐Chun, Jan, Chia‐Ing, Cho, Der‐Yang, Lin, Chen‐Yu, Huang, Wei‐Hsaing, Chen, Yeh, Wang, Sin‐Ting, Chiu, Ya‐Hsu, Pan, Chih‐Ming, Lin, Yu‐Chuan, Chen, Mei‐Chih, Chiu, Shao‐Chih, Lin, Pei‐Ying, Lin, Ting‐Hsun, Huang, Shi‐Wei

2023

Overview

HLA‐G is considered as an immune checkpoint protein and a tumor‐associated antigen. In the previous work, it is reported that CAR‐NK targeting of HLA‐G can be used to treat certain solid tumors. However, the frequent co‐expression of PD‐L1 and HLA‐G) and up‐regulation of PD‐L1 after adoptive immunotherapy may decrease the effectiveness of HLA‐G‐CAR. Therefore, simultaneous targeting of HLA‐G and PD‐L1 by multi‐specific CAR could represent an appropriate solution. Furthermore, gamma‐delta T (γδT) cells exhibit MHC‐independent cytotoxicity against tumor cells and possess allogeneic potential. The utilization of nanobodies offers flexibility for CAR engineering and the ability to recognize novel epitopes. In this study, Vδ2 γδT cells are used as effector cells and electroporated with an mRNA‐driven, nanobody‐based HLA‐G‐CAR with a secreted PD‐L1/CD3ε Bispecific T‐cell engager (BiTE) construct (Nb‐CAR.BiTE). Both in vivo and in vitro experiments reveal that the Nb‐CAR.BiTE‐γδT cells could effectively eliminate PD‐L1 and/or HLA‐G‐positive solid tumors. The secreted PD‐L1/CD3ε Nb‐BiTE can not only redirect Nb‐CAR‐γδT but also recruit un‐transduced bystander T cells against tumor cells expressing PD‐L1, thereby enhancing the activity of Nb‐CAR‐γδT therapy. Furthermore, evidence is provided that Nb‐CAR.BiTE redirectes γδT into tumor‐implanted tissues and that the secreted Nb‐BiTE is restricted to the tumor site without apparent toxicity. Elevated PD‐L1 in solid tumors increases the risk of immune escape from HLA‐G‐CAR cell therapy. The bicistronic mRNA construct that drives PD‐L1 Nb‐BiTE and HLA‐G Nb‐CAR in γδT cells via electroporation is designed to address this issue. This Nb‐CAR.BiTE‐γδT therapy can overcome HLA‐G and PD‐L1 dilemma and even kill tumor cells with inadequate antigen expression, resulting in potent anti‐tumor activity without apparent toxicity.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc,Wiley
• Subject: antigen heterogenicity / Antigens / bispecific T‐cell engager / Cells / chimeric antigen receptor / Cytotoxicity / gamma‐delta T / Immunotherapy / Lymphocytes / mRNA / nanobody / Tumors