Myeloid cell–targeted STAT3 inhibition sensitizes head and neck cancers to radiotherapy and T cell–mediated immunity
Dayson Moreira, … , Erminia Massarelli, Marcin Kortylewski
Dayson Moreira, … , Erminia Massarelli, Marcin Kortylewski
Published November 24, 2020
Citation Information: J Clin Invest. 2021;131(2):e137001. https://doi.org/10.1172/JCI137001.
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Research Article Immunology Oncology

Myeloid cell–targeted STAT3 inhibition sensitizes head and neck cancers to radiotherapy and T cell–mediated immunity

Abstract

The tumor microenvironment affects the outcome of radiotherapy against head and neck squamous cell carcinoma (HNSCC). We recently found that tolerogenic myeloid cells accumulate in the circulation of HNSCC patients undergoing radiotherapy. Here, we analyzed tumor-containing lymph node biopsies collected from these patients. After 2 weeks of radiotherapy, we found an increase in tumor-associated macrophages (TAMs) with activated STAT3, while CD8+ T cells were reduced as detected using multiplex IHC. Gene expression profiling indicated upregulation of M2 macrophage–related genes (CD163, CD206), immunosuppressive mediators (ARG1, LIF, TGFB1), and Th2 cytokines (IL4, IL5) in irradiated tumors. We next validated STAT3 as a potential target in human HNSCC-associated TAMs, using UM-SCC1 xenotransplants in humanized mice. Local injections of myeloid cell–targeted STAT3 antisense oligonucleotide (CpG-STAT3ASO) activated human DCs/macrophages and promoted CD8+ T cell recruitment, thereby arresting UM-SCC1 tumor growth. Furthermore, CpG-STAT3ASO synergized with tumor irradiation against syngeneic HPV+ mEERL and HPV– MOC2 HNSCC tumors in mice, triggering tumor regression and/or extending animal survival. The antitumor immune responses were CD8+ and CD4+ T cell dependent and associated with the activation of antigen-presenting cells (DCs/M1 macrophages) and increased CD8+ to regulatory T cell ratio. Our observations suggest that targeted inhibition of STAT3 in tumor-associated myeloid cells augments the efficacy of radiotherapy against HNSCC.

Authors

Dayson Moreira, Sagus Sampath, Haejung Won, Seok Voon White, Yu-Lin Su, Marice Alcantara, Chongkai Wang, Peter Lee, Ellie Maghami, Erminia Massarelli, Marcin Kortylewski

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Figure 6

CD8+ T cell recruitment with concomitant decrease in regulatory T cells drives the antitumor immune response induced by the combination of radiation therapy with CpG-STAT3ASO.

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CD8+ T cell recruitment with concomitant decrease in regulatory T cells ...
MOC2 and mEERL tumors were established in immunocompetent mice and treated as described in the Figure 4 legend. Tumors and tumor-draining lymph nodes (TDLNs) were collected after the third treatment with CpG-STAT3ASO. (A and B) Percentages of CD8+ T cells and Tregs as well as the CD8+/Treg ratio in TDLNs (A) or in MOC2 tumors (B) as measured by flow cytometry. (C and D) The CD8+/Treg ratio in TDLNs (C) or in mEERL tumors (D). Shown are individual data points and mean ± SEM (n = 6/group). (E) CD8+ or CD4+ T cell depletion using specific antibodies abrogates the therapeutic antitumor effect of the combined CpG-STAT3ASO/radiotherapy against MOC2 tumors. After tumors were established (~150 mm3), mice were treated using specific antibodies against CD4 and CD8 to deplete specific T cell subsets, control IgGs, or vehicle only (PBS). Subsequently, the mice were treated using local tumor irradiation (13 Gy) together with CpG-STAT3ASO (5 mg/kg intratumorally). The red arrow indicates tumor irradiation (Rx), black arrows indicate oligonucleotide injection. Data presented as mean ± SEM (n = 5/group). *P < 0.05, **P < 0.01, ***P < 0.001 by 1-way ANOVA with Tukey’s post hoc test (A–D) or 2-way ANOVA with Tukey’s post hoc test (E).