Selective HLA knockdown and PD-L1 expression prevent allogeneic CAR-NK cell rejection and enhance safety and anti-tumor responses in xenograft mice
Fuguo Liu, Mubin Tarannum, Yingjie Zhao, Yiming J. Zhang, James Dongjoo Ham, Kewen Lei, Yuhao Qiang, Xingyu Deng, Maily Nguyen, Khanhlinh Dinh, Shaobo Yang, Alaa Kassim Ali, Toni K. Choueiri, Jerome Ritz, Rizwan Romee, Jianzhu Chen
Abstract
Allogeneic cellular immunotherapy exhibits promising efficacy for cancer treatment, but donor cell rejection remains a major barrier. Here, we systematically evaluate human leukocyte antigens (HLA) and immune checkpoints PD-L1, HLA-E, and CD47 in the rejection of allogeneic NK cells and identify CD8+ T cells as the dominant cell type mediating allorejection. We demonstrate that a single gene construct that combines an shRNA that selectively interferes with HLA class I but not HLA-E expression, a chimeric antigen receptor (CAR), and PD-L1 or single-chain HLA-E (SCE) enables the one-step construction of allogeneic CAR-NK cells that evade host-mediated rejection both in vitro and in a xenograft mouse model. Furthermore, CAR-NK cells overexpressing PD-L1 or SCE effectively kill tumor cells through the upregulation of cytotoxic genes and reduced exhaustion and exhibit a favorable safety profile due to the decreased production of inflammatory cytokines involved in cytokine release syndrome. Thus, our approach represents a promising strategy in enabling “off-the-shelf” allogeneic cellular immunotherapies. The use of donor-derived CAR-NK cells is limited by CD8 T cell-mediated allorejection. Here, the authors describe a one-step approach, based on selective HLA knockdown and overexpression of PD-L1, that allows allogeneic modified CAR-NK cells to escape rejection by the host immune system while exhibiting enhanced anti-tumor activity and safety in preclinical mouse models.