IL-32γ potentiates tumor immunity in melanoma
Thomas Gruber, … , Antoni Ribas, Mirjam Schenk
Thomas Gruber, … , Antoni Ribas, Mirjam Schenk
Published August 25, 2020
Citation Information: JCI Insight. 2020;5(18):e138772. https://doi.org/10.1172/jci.insight.138772.
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Research Article Immunology Oncology

IL-32γ potentiates tumor immunity in melanoma

Abstract

Myeloid cells orchestrate the antitumor immune response and influence the efficacy of immune checkpoint blockade (ICB) therapies. We and others have previously shown that IL-32 mediates DC differentiation and macrophage activation. Here, we demonstrate that IL-32 expression in human melanoma positively correlates with overall survival, response to ICB, and an immune-inflamed tumor microenvironment (TME) enriched in mature DC, M1 macrophages, and CD8+ T cells. Treatment of B16F10 murine melanomas with IL-32 increased the frequencies of activated, tumor-specific CD8+ T cells, leading to the induction of systemic tumor immunity. Our mechanistic in vivo studies revealed a potentially novel role of IL-32 in activating intratumoral DC and macrophages to act in concert to prime CD8+ T cells and recruit them into the TME through CCL5. Thereby, IL-32 treatment reduced tumor growth and rendered ICB-resistant B16F10 tumors responsive to anti–PD-1 therapy without toxicity. Furthermore, increased baseline IL-32 gene expression was associated with response to nivolumab and pembrolizumab in 2 independent cohorts of patients with melanoma, implying that IL-32 is a predictive biomarker for anti–PD-1 therapy. Collectively, this study suggests IL-32 as a potent adjuvant in immunotherapy to enhance the efficacy of ICB in patients with non–T cell–inflamed TME.

Authors

Thomas Gruber, Mirela Kremenovic, Hassan Sadozai, Nives Rombini, Lukas Baeriswyl, Fabienne Maibach, Robert L. Modlin, Michel Gilliet, Diego von Werdt, Robert E. Hunger, S. Morteza Seyed Jafari, Giulia Parisi, Gabriel Abril-Rodriguez, Antoni Ribas, Mirjam Schenk

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Figure 6

IL-32 treatment is synergistic with concurrent anti-PD1 in mice, and IL-32 expression is predictive for response to anti-PD1 therapy in patients with melanoma.

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IL-32 treatment is synergistic with concurrent anti-PD1 in mice, and IL-...
(A) Experimental setup for B16F10 dual treatment with IL-32 and anti–PD-1 antibody used in B–D. (B) Tumor growth shown as mean ± SEM (IL-32, aPD1, IL-32 + aPD1, n = 23; PBS, n = 24). Statistical significance was determined by 2-way ANOVA followed by Šidák’s multiple comparisons test. *P = 0.0199, ****P < 0.0001. (C) Frequencies of CD45+ immune cells and (D) CD4+ T cells and CD8+ T cells as a proportion of viable cells (n = 21–23). P values were computed by 1-way ANOVA followed by Tukey’s multiple comparisons test. Data are represented as mean ± SEM. (E) Experimental setup for survival and safety assessment with additional IL-32 and anti–PD-1 treatments used for F–J. (F) Kaplan-Meier survival curves. Significance was determined by log-rank test (IL-32, IL-32 + aPD-1, n = 15; PBS, n = 17). (G) Body temperature and (H) body weight of mice upon treatment (n = 6). (I) White blood cell (WBC), lymphocyte, and red blood cell (RBC) counts as cells/μl blood (n ≥ 4). Blood was obtained when mice were euthanized. Differences between groups were determined using 2-way ANOVA followed by Šidák’s multiple comparisons test. (J) IL32 mRNA expression levels in biopsies from patients with melanoma before anti–PD-1 (nivolumab) treatment. (K) IL32 mRNA expression in biopsies of patients with melanoma receiving neoadjuvant pembrolizumab treatment (nonrecurrence, n = 8; recurrence, n = 5). The data set was obtained from GSE123728. (J and K) P values were computed by 2-tailed, unpaired Student’s t test. Error bars show mean ± SEM. (L) Multivariate logistic regression between response to nivolumab and mRNA expression of the indicated genes or mutational load. (J and L) Patients were stratified into responders (complete response and partial response, n = 10) and nonresponders (stable disease or progressive disease, n = 39). The data set was obtained from GSE91061.