Tumor control via targeting PD-L1 with chimeric antigen receptor modified NK cells

Abstract

27Failed T cell-based immunotherapies in the presence of genomic alterations in antigen presentations 28 pathways may be overcome by NK cell-based immunotherapy. This approach may still be limited by the 29 presence of immunosuppressive myeloid populations. Here we demonstrate that NK cells (haNKs) 30 engineered to express a PD-L1 chimeric antigen receptor (CAR) haNKs killed a panel of human and 31 murine head and neck cancer cells at low effector-to-target ratios in a PD-L1-dependent fashion. 32 Treatment of syngeneic tumors resulted in CD8 and PD-L1-dependent tumor rejection or growth 33 inhibition and a reduction in myeloid cells endogenously expressing high levels of PD-L1. Treatment of 34 xenograft tumors resulted in PD-L1 dependent tumor growth inhibition. PD-L1 CAR haNKs reduced 35 levels of macrophages and other myeloid cells endogenously expressing high PD-L1 in peripheral blood 36 from patients with head and neck cancer. The clinical study of PD-L1 CAR haNKs is warranted. 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 3 Background 53 T cell-based immunotherapy, such as immune checkpoint blockade or adoptive T cell transfer, is 54 limited by the ability of T cells to detect major histocompatibility complex (MHC)-presented antigen by 55 tumor cells. Through selective immune pressure during tumorigenesis and progression and genomic 56 instability, subpopulations of tumor cells acquire mutations that lead to defective type II interferon (IFN) 57 responses and altered antigen processing and presentation (1, 2). The presence of these mutations predicts 58 failure to respond to immune checkpoint blockade and adoptive T cell transfer immunotherapy(3-6). 59Natural killer (NK) cell-based immunotherapy may overcome genetic mechanisms of resistance 60 to T cell-based immunotherapy through antigen-and MHC-independent recognition of malignant cells. 61NK cells express germ-line receptors that are either stimulatory or inhibitory, and the summation of these 62 signals determines activation status (7). NK-92 cells, derived from a Non-Hodgkin's lymphoma patient, 63 can be continuously expanded in culture and following irradiation, can be safely administered in high 64 doses to patients with cancer(8-10). High-affinity NK (haNK) cells are NK-92 cells engineered to express 65 endoplasmic reticulum-retained IL-2(11), have demonstrated potent effector function in numerous pre-66 clinical models(12, 13), and following irradiation, can also be safely administered in high doses to 67 patients(14). haNKs represent an "off the shelf" NK cellular therapy available for pre-clinical and clinical 68 study. However, barriers within the tumor microenvironment that further limit T cell activation and 69 function such as the presence of immunosuppressive myeloid cells also can limit the activation and 70 function of NK cells (15, 16). Thus, addressing the presence of immunosuppressive myeloid cell 71 populations in the periphery and tumor microenvironment of patients with cancer is likely to be required 72 for effective NK cell-bas...

Endoplasmic Reticulum Stress Promotes The Release of Exosomal PD-L1 From Head and Neck Cancer Cells and Facilitates M2 Macrophage Differentiation

“…PD-L1 can inhibit T-cell activation and contribute to tumour immune evasion in many cancers, like liver cancer and mammary cancer, and macrophages that in ltrate into liver cancers can express higher levels of PD-L1; therefore, we assumed that the same trend would occur in OSCC. [32][33][34] In this study, we found that the macrophages that in ltrated into ER-stressed OSCC tissues expressed high levels of PD-L1 and that the PD-L1 levels were negatively correlated with overall survival. Macrophages are classi ed into M1 and M2 macrophages, where M1 macrophages play a protective role and M2 macrophages promote tumour growth.…”

“Built‐in” PD‐1 blocker to rescue NK‐92 activity from PD‐L1–mediated tumor escape mechanisms

“…Here we exploited the PD‐1/PD‐L1 pathway and showed that expression of a truncated PD‐1 receptor protected NK‐92 cells from PD‐1–mediated inhibition, and, importantly, increased their ability to identify and kill PD‐L1+ tumor cells. As mentioned above, similar strategies were recently tested in a derivative of NK‐92, t‐haNK cells, using an anti‐PD‐L1 CAR, and demonstrated efficacy 64,66 . They unfortunately did not compare their modified cells with the parental strain as we did here and could consequently not assess improved efficacy of the modified versus the original NK cell in vivo.…”

PRDX-1 Supports the Survival and Antitumor Activity of Primary and CAR-Modified NK Cells under Oxidative Stress

“…The strategy of genetic engineering of effector cells to promote their activity is an attractive approach already implemented in preclinical and clinical settings (58,59). Moreover, NK-92 cells have already demonstrated potent effector function in preclinical models (60), and following irradiation, can also be safely administered in high doses to patients as an "off the shelf" cell therapy product (61).…”