IL-18–secreting CAR T cells targeting DLL3 are highly effective in small cell lung cancer models
Janneke E. Jaspers, … , Charles M. Rudin, Renier J. Brentjens
Janneke E. Jaspers, … , Charles M. Rudin, Renier J. Brentjens
Published March 23, 2023
Citation Information: J Clin Invest. 2023;133(9):e166028. https://doi.org/10.1172/JCI166028.
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Research Article Immunology Oncology

IL-18–secreting CAR T cells targeting DLL3 are highly effective in small cell lung cancer models

Abstract

Patients with small cell lung cancer (SCLC) generally have a poor prognosis and a median overall survival of only about 13 months, indicating the urgent need for novel therapies. Delta-like protein 3 (DLL3) has been identified as a tumor-specific cell surface marker on neuroendocrine cancers, including SCLC. In this study, we developed a chimeric antigen receptor (CAR) against DLL3 that displays antitumor efficacy in xenograft and murine SCLC models. CAR T cell expression of the proinflammatory cytokine IL-18 greatly enhanced the potency of DLL3-targeting CAR T cell therapy. In a murine metastatic SCLC model, IL-18 production increased the activation of both CAR T cells and endogenous tumor-infiltrating lymphocytes. We also observed an increased infiltration, repolarization, and activation of antigen-presenting cells. Additionally, human IL-18–secreting anti-DLL3 CAR T cells showed an increased memory phenotype, less exhaustion, and induced durable responses in multiple SCLC models, an effect that could be further enhanced with anti–PD-1 blockade. All together, these results define DLL3-targeting CAR T cells that produce IL-18 as a potentially promising novel strategy against DLL3-expressing solid tumors.

Authors

Janneke E. Jaspers, Jonathan F. Khan, William D. Godfrey, Andrea V. Lopez, Metamia Ciampricotti, Charles M. Rudin, Renier J. Brentjens

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Figure 5

Human DLL3-targeting CAR T cells that secrete IL-18 are effective against SCLC and can be further potentiated by late-onset anti–PD-1 therapy.

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Human DLL3-targeting CAR T cells that secrete IL-18 are effective agains...
(A) Schematic overview of the CAR design. EGFRt, truncated EGFR; scFv, single-chain variant fragment. (B) Levels of IL-18 and IFN-γ in cell culture supernatant of cocultures of the indicated CAR T cells and DLL3-expressing target cells. ***P < 0.001, ****P < 0.0001 (Student’s t test, n = 4). (C) Luciferase killing assay with H82 (DLL3+) and H69 (DLL3lo) SCLC cells. (D) CAR T cell proliferation in cocultures with H82 or H69 SCLC cells (E/T ratio of 1:5, n = 3, representative result from 3 independent experiments). (E) Growth curve of metastatic H82-SCLC tumors in mice that received 1 × 106 SC16.8 CAR T cells that did or did not secrete IL-18 (n = 4–5). (F–J) Livers of mice were subjected to flow cytometry analysis 9 days after CAR T cell treatment of mice with metastatic H82-SCLC tumors. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 (2-way ANOVA, n = 3). (F) Cell count of GFP+ H82 tumor cells (left) and PD-L1 expression on these GFP+ cells (right). (G) Cell count of EGFRt+ CAR T cells in the liver (left) and CD8/CD4 ratio of the CAR T cells (right). (H) Quantification of CD62L+ central memory CAR T cells. (I) Quantification of CD4+ and CD8+ CAR T cells that are quadruple negative (left) or quadruple positive (right) for the exhaustion markers PD-1, TIGIT, TIM3, and LAG3. (J) Representative flow plots and mean fluorescence intensity (MFI) of T cell activation markers CD71 and HLA-DR on CAR T cells. (K) Growth curve of metastatic H82-SCLC tumors in mice that received 0.3 × 106 CAR T cells alone or in combination with twice weekly 250 μg anti-human anti–PD-1 antibody, starting on day 18 (n = 4). (L) Bioluminescence imaging of same mice as in K, on days 17, 21, and 26 after tumor cell injection.