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 4

Local irradiation combined with intratumoral delivery of CpG-STAT3ASO improves the response to the irradiation in mice bearing HNSCC tumors independently of the HPV status.

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Local irradiation combined with intratumoral delivery of CpG-STAT3ASO im...
(A and B) C57BL/6 mice were injected s.c. in the flank with mouse syngeneic HPV+ mEERL. Established tumors were treated with 5 mg/kg CpG-STAT3ASO, STAT3ASO, CpG-srcON, or vehicle (PBS) every other day. After 4 treatments the tumors were collected, photographed, and weighed (A), and then STAT3 expression was measured using real-time qPCR (B) (n = 5). PPIA, peptidyl-prolyl cis-trans isomerase A. (C) HPV– MOC2 cancer cells were engrafted in both flanks of mice to generate dual-tumor models. After tumors were established (~150 mm3), mice were treated using CpG-STAT3ASO (5 mg/kg) injected intratumorally every other day for a total of 6 times (black arrows), a single dose of local tumor irradiation (RT: 13 Gy, red arrow), the combination of these treatments (CpG-STAT3ASO+RT), or vehicle alone (PBS). MOC2 tumor growth kinetics were measured using a caliper at treated (left) and at distant (right) tumor sites (n = 6/group). (D) The CpG-STAT3ASO plus RT combination treatment improves survival of MOC2 tumor–bearing mice; shown is the Kaplan-Meier survival curve (n = 9–10). (E and F) Comparison of antitumor effects of radiotherapy alone, CpG-STAT3ASO alone, and the combination of both. C57BL/6 mice were injected s.c. in the flank with syngeneic HPV+ mEERL (E) or HPV– mEERLsh (F) HNSCC cells. Mice with established tumors were treated as described in C. Shown are representative results from 1 of 2 independent experiments (n = 6/group). Data presented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001 by 1-way ANOVA with Tukey’s post hoc test (A and B) or 2-way ANOVA with Tukey’s post hoc test (C, E, and F).