PD-L1 targeting high-affinity NK (t-haNK) cells induce direct antitumor effects and target suppressive MDSC populations.

Abstract

BACKGROUND:

Although immune checkpoint inhibitors have revolutionized cancer treatment, clinical benefit with this class of agents has been limited to a subset of patients. Hence, more effective means to target tumor cells that express immune checkpoint molecules should be developed. For the first time, we report a novel natural killer (NK) cell line, programmed death-ligand 1 (PD-L1) targeting high-affinity natural killer (t-haNK), which was derived from NK-92 and was engineered to express high-affinity CD16, endoplasmic reticulum-retained interleukin (IL)-2, and a PD-L1-specific chimeric antigen receptor (CAR). We show that PD-L1 t-haNK cells also retained the expression of native NK receptors and carried a high content of granzyme and perforin granules.

METHODS:

NanoString, flow cytometry, and immunofluorescence analyses were performed to characterize the phenotype of irradiated PD-L1 t-haNK cells. In vitro PD-L1 t-haNK cell activity against cancer cell lines and human peripheral blood mononuclear cells (PBMCs) was determined via flow-based and 111In-release killing assays. The antitumor effect of PD-L1 t-haNK cells in vivo was investigated using MDA-MB-231, H460, and HTB1 xenograft models in NOD-scid IL2Rgammanull (NSG) mice. Additionally, the antitumor effect of PD-L1 t-haNK cells, in combination with anti-PD-1 and N-803, an IL-15 superagonist, was evaluated using mouse oral cancer 1 syngeneic model in C57BL/6 mice.

RESULTS:

We show that PD-L1 t-haNK cells expressed PD-L1-targeting CAR and CD16, retained the expression of native NK receptors, and carried a high content of granzyme and perforin granules. In vitro, we demonstrate the ability of irradiated PD-L1 t-haNK cells to lyse 20 of the 20 human cancer cell lines tested, including triple negative breast cancer (TNBC) and lung, urogenital, and gastric cancer cells. The cytotoxicity of PD-L1 t-haNK cells was correlated to the PD-L1 expression of the tumor targets and can be improved by pretreating the targets with interferon (IFN)-γ. In vivo, irradiated PD-L1 t-haNK cells inhibited the growth of engrafted TNBC and lung and bladder tumors in NSG mice. The combination of PD-L1 t-haNK cells with N-803 and anti-PD-1 antibody resulted in superior tumor growth control of engrafted oral cavity squamous carcinoma tumors in C57BL/6 mice. In addition, when cocultured with human PBMCs, PD-L1 t-haNK cells preferentially lysed the myeloid-derived suppressor cell population but not other immune cell types.

CONCLUSION:

These studies demonstrate the antitumor efficacy of PD-L1 t-haNK cells and provide a rationale for the potential use of these cells in clinical studies.

• Authors: Kellsye P Fabian, Michelle R Padget, Renee N Donahue, Kristen Solocinski, Yvette Robbins, Clint T Allen, John H Lee, Shahrooz Rabizadeh, Patrick Soon-Shiong, Jeffrey Schlom, James W Hodge
• Journal: Journal for immunotherapy of cancer (J Immunother Cancer) Vol. 8 Issue 1 (05 2020) ISSN: 2051-1426 [Electronic] England
• PMID: 32439799 (Publication Type: Journal Article, Research Support, N.I.H., Intramural)
• Copyright: © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Chemical References

• B7-H1 Antigen
• CD274 protein, human
• FCGR3B protein, human
• GPI-Linked Proteins
• IL2 protein, human
• Immune Checkpoint Inhibitors
• Interleukin-2
• PDCD1 protein, human
• Programmed Cell Death 1 Receptor
• Receptors, Chimeric Antigen
• Receptors, IgG

Topics

• Animals
• B7-H1 Antigen (antagonists & inhibitors, immunology)
• Cell Line, Tumor
• Combined Modality Therapy (methods)
• Female
• GPI-Linked Proteins (genetics, immunology, metabolism)
• Humans
• Immune Checkpoint Inhibitors (pharmacology, therapeutic use)
• Immunotherapy, Adoptive (methods)
• Interleukin-2 (genetics, immunology, metabolism)
• Killer Cells, Natural (immunology, metabolism, transplantation)
• Mice
• Myeloid-Derived Suppressor Cells (drug effects, immunology)
• Neoplasms (immunology, pathology, therapy)
• Programmed Cell Death 1 Receptor (antagonists & inhibitors, immunology)
• Protein Engineering
• Receptors, Chimeric Antigen (genetics, immunology, metabolism)
• Receptors, IgG (genetics, immunology, metabolism)
• Tumor Escape (drug effects, immunology)
• Xenograft Model Antitumor Assays