A tumor-intrinsic PD-L1/NLRP3 inflammasome signaling pathway drives resistance to anti–PD-1 immunotherapy
Balamayoora Theivanthiran, Kathy S. Evans, Nicholas C. DeVito, Michael Plebanek, Michael Sturdivant, Luke P. Wachsmuth, April K.S. Salama, Yubin Kang, David Hsu, Justin M. Balko, Douglas B. Johnson, Mark Starr, Andrew B. Nixon, Alisha Holtzhausen, Brent A. Hanks
Balamayoora Theivanthiran, Kathy S. Evans, Nicholas C. DeVito, Michael Plebanek, Michael Sturdivant, Luke P. Wachsmuth, April K.S. Salama, Yubin Kang, David Hsu, Justin M. Balko, Douglas B. Johnson, Mark Starr, Andrew B. Nixon, Alisha Holtzhausen, Brent A. Hanks
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Research Article Immunology Oncology

A tumor-intrinsic PD-L1/NLRP3 inflammasome signaling pathway drives resistance to anti–PD-1 immunotherapy

Abstract

An in-depth understanding of immune escape mechanisms in cancer is likely to lead to innovative advances in immunotherapeutic strategies. However, much remains unknown regarding these mechanisms and how they impact immunotherapy resistance. Using several preclinical tumor models as well as clinical specimens, we identified a mechanism whereby CD8+ T cell activation in response to programmed cell death 1 (PD-1) blockade induced a programmed death ligand 1/NOD-, LRR-, and pyrin domain–containing protein 3 (PD-L1/NLRP3) inflammasome signaling cascade that ultimately led to the recruitment of granulocytic myeloid-derived suppressor cells (PMN-MDSCs) into tumor tissues, thereby dampening the resulting antitumor immune response. The genetic and pharmacologic inhibition of NLRP3 suppressed PMN-MDSC tumor infiltration and significantly augmented the efficacy of anti–PD-1 antibody immunotherapy. This pathway therefore represents a tumor-intrinsic mechanism of adaptive resistance to anti–PD-1 checkpoint inhibitor immunotherapy and is a promising target for future translational research.

Authors

Balamayoora Theivanthiran, Kathy S. Evans, Nicholas C. DeVito, Michael Plebanek, Michael Sturdivant, Luke P. Wachsmuth, April K.S. Salama, Yubin Kang, David Hsu, Justin M. Balko, Douglas B. Johnson, Mark Starr, Andrew B. Nixon, Alisha Holtzhausen, Brent A. Hanks

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Figure 1

PMN-MDSC accumulation contributes to tumor progression following anti–PD-1 Ab immunotherapy.

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PMN-MDSC accumulation contributes to tumor progression following anti–PD...
(A) Schematic overview of the adaptive resistance pathway. (B) RNA-Seq differential gene expression analysis of tumor tissues following treatment of the autochthonous BRAFV600E PTEN–/– melanoma model with anti–PD-1 Ab therapy versus IgG isotype control (Ctrl) (n = 3). (C) qRT-PCR analysis of target genes of interest in serial tumor fine-needle aspiration (FNA) biopsy specimens harvested from the transgenic BRAFV600E PTEN–/– melanoma model treated with anti–PD-1 Ab versus IgG isotype control (n = 5). (D) Gr-1 immunohistochemical analysis of transgenic BRAFV600E PTEN–/– melanoma tissues following treatment with anti–PD-1 Ab versus IgG isotype control. Original magnification, ×40. Gr-1 staining is shown in red. Images are representative of 3 tumors per group. (E) PMN-MDSC flow cytometric analysis of transgenic BRAFV600E PTEN–/– melanoma tissues following treatment with anti–PD-1 Ab versus IgG isotype control. PMN-MDSCs were defined as live+CD45+CD11b+Ly6G+Ly6CintF4/80– cells. Shown are a representative flow dot plot and quantification graph of PMN-MDSC flow cytometric data (n = 5). (F) qRT-PCR analysis of CXCR2 ligands in BRAFV600E PTEN–/– melanoma tissues treated with anti–PD-1 Ab following CD8+ T cell ablation in vivo (n = 3). (G) In vivo tumor study of BRAFV600E PTEN–/– melanoma genetically silenced for CXCL5. Quantitation of tumor-infiltrating PMN-MDSCs by flow cytometry is shown along with an in vivo tumor growth curve of CXCL5-silenced BRAFV600E PTEN–/– melanoma versus BRAFV600E PTEN–/– NTC melanoma control tumors treated with anti–PD-1 Ab. Data were normalized to tumors treated with IgG isotype control (n = 5). (H) Combination treatment with anti–PD-1 Ab and CXCR2 inhibitor (CXCR2i) in an in vivo BRAFV600E PTEN–/– melanoma study (n = 5). Graphs show flow cytometric analysis of tumor-infiltrating PMN-MDSCs and live+CD45+CD3+CD8+ T cells. *P < 0.05, **P < 0.005, and ***P < 0.0005, by Student’s t test with Holm-Sidak post hoc correction for multiple comparisons (B, C, and F), Student’s t test (E and G), or 1-way ANOVA with Sidak’s post hoc multiple comparisons test (H). See also Supplemental Figures 1, 2, and 5C.