Adjuvant COX inhibition augments STING signaling and cytolytic T cell infiltration in irradiated 4T1 tumors
Lisa A. Ridnour, … , Stephen J. Lockett, David A. Wink
Lisa A. Ridnour, … , Stephen J. Lockett, David A. Wink
Published June 24, 2024
Citation Information: JCI Insight. 2024;9(12):e165356. https://doi.org/10.1172/jci.insight.165356.
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Research Article Inflammation Oncology

Adjuvant COX inhibition augments STING signaling and cytolytic T cell infiltration in irradiated 4T1 tumors

Abstract

Immune therapy is the new frontier of cancer treatment. Therapeutic radiation is a known inducer of immune response and can be limited by immunosuppressive mediators including cyclooxygenase-2 (COX2) that is highly expressed in aggressive triple negative breast cancer (TNBC). A clinical cohort of TNBC tumors revealed poor radiation therapeutic efficacy in tumors expressing high COX2. Herein, we show that radiation combined with adjuvant NSAID (indomethacin) treatment provides a powerful combination to reduce both primary tumor growth and lung metastasis in aggressive 4T1 TNBC tumors, which occurs in part through increased antitumor immune response. Spatial immunological changes including augmented lymphoid infiltration into the tumor epithelium and locally increased cGAS/STING1 and type I IFN gene expression were observed in radiation-indomethacin–treated 4T1 tumors. Thus, radiation and adjuvant NSAID treatment shifts “immune desert phenotypes” toward antitumor M1/TH1 immune mediators in these immunologically challenging tumors. Importantly, radiation-indomethacin combination treatment improved local control of the primary lesion, reduced metastatic burden, and increased median survival when compared with radiation treatment alone. These results show that clinically available NSAIDs can improve radiation therapeutic efficacy through increased antitumor immune response and augmented local generation of cGAS/STING1 and type I IFNs.

Authors

Lisa A. Ridnour, Robert Y.S. Cheng, Noemi Kedei, Veena Somasundaram, Dibyangana D. Bhattacharyya, Debashree Basudhar, Adelaide L. Wink, Abigail J. Walke, Caleb Kim, William F. Heinz, Elijah F. Edmondson, Donna O. Butcher, Andrew C. Warner, Tiffany H. Dorsey, Milind Pore, Robert J. Kinders, Stanley Lipkowitz, Richard J. Bryant, Jens Rittscher, Stephen T.C. Wong, Stephen M. Hewitt, Jenny C. Chang, Aliaa Shalaby, Grace M. Callagy, Sharon A. Glynn, Stefan Ambs, Stephen K. Anderson, Daniel W. McVicar, Stephen J. Lockett, David A. Wink

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Figure 2

CD8+ T cell spatial distribution in COX2hi and COX2lo expressing tumors.

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CD8+ T cell spatial distribution in COX2hi and COX2lo expressing tumors....
(A) CD8+ T cells (red stain), CK tumor marker (blue stain), and DAPI (white stain) showing COX2lo “Hot-Inflamed” tumor with high CD8+ T cell penetration into tumor epithelium, COX2hi “Cold-Excluded” tumor showing CD8+ T cells restricted to stroma, and COX2hi “Cold-Immune Desert” showing few or absence of CD8+ T cells in the tumor epithelium. Scale bars: 200 μm. (B) CD8+ T cell quantification showing increased total CD8+ T cells in COX2lo (red circles n = 10) versus COX2hi (blue circles n = 6) tumors. (C) Increased CD8+ T cell/tumor CKSOX10 ratio in COX2lo (red) versus COX2hi (blue) tumors. (D) The left graph shows significantly elevated CD8+T cell infiltration in COX2lo versus COX2hi tumors. The middle graph shows significantly reduced CD8+ T cell infiltration in COX2hi annotated tumor regions where CD8+ T cells are highly stroma restricted. The right graph shows no significant difference between CD8+ T cells in tumor versus stroma regions in COX2lo tumors. (E) CD8+ T cell density per mm2 localized in tumor- (left) or stroma-annotated (right) regions in COX2lo (red) versus COX2hi (blue) tumors. (F) Density heat map showing elevated CD8+ T cell aggregation in COX2lo versus COX2hi tumors. Scale bar: 1 mm. (G) Increased number of CD8+ T cells infiltrating from tumor-stroma interface into tumor epithelium in COX2lo (red bar) versus COX2hi (blue bar) tumors. (H) COX2lo expressing tumors (left panel) exhibit dramatically increased number and penetration of CD8+ T cells into tumor epithelium (white arrows). In contrast, CD8+ T cell (white arrowhead) in COX2hi tumors (right panel) are stroma restricted. DAPI (white), COX2 (green), CD8+ T cell (red), and CKSOX10 tumor marker (blue) are shown. (I) Increased COX2/CD8+ T cell ratios in patients with TNBC who succumbed to disease versus those who survived (Deceased versus Alive) at 5 years after diagnosis. *P ≤ 0.05, **P ≤ 0.0075 using Mann-Whitney U or Welch’s test.