STING agonist 8803 reprograms the immune microenvironment and increases survival in preclinical models of glioblastoma
Hinda Najem, … , Michael A. Curran, Amy B. Heimberger
Hinda Najem, … , Michael A. Curran, Amy B. Heimberger
Published June 17, 2024
Citation Information: J Clin Invest. 2024;134(12):e175033. https://doi.org/10.1172/JCI175033.
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Research Article Immunology Oncology

STING agonist 8803 reprograms the immune microenvironment and increases survival in preclinical models of glioblastoma

Abstract

STING agonists can reprogram the tumor microenvironment to induce immunological clearance within the central nervous system. Using multiplexed sequential immunofluorescence (SeqIF) and the Ivy Glioblastoma Atlas, STING expression was found in myeloid populations and in the perivascular space. The STING agonist 8803 increased median survival in multiple preclinical models of glioblastoma, including QPP8, an immune checkpoint blockade–resistant model, where 100% of mice were cured. Ex vivo flow cytometry profiling during the therapeutic window demonstrated increases in myeloid tumor trafficking and activation, alongside enhancement of CD8+ T cell and NK effector responses. Treatment with 8803 reprogrammed microglia to express costimulatory CD80/CD86 and iNOS, while decreasing immunosuppressive CD206 and arginase. In humanized mice, where tumor cell STING is epigenetically silenced, 8803 therapeutic activity was maintained, further attesting to myeloid dependency and reprogramming. Although the combination with a STAT3 inhibitor did not further enhance STING agonist activity, the addition of anti–PD-1 antibodies to 8803 treatment enhanced survival in an immune checkpoint blockade–responsive glioma model. In summary, 8803 as a monotherapy demonstrates marked in vivo therapeutic activity, meriting consideration for clinical translation.

Authors

Hinda Najem, Spencer T. Lea, Shashwat Tripathi, Lisa Hurley, Chao-Hsien Chen, Ivana William, Moloud Sooreshjani, Michelle Bowie, Genevieve Hartley, Corey Dussold, Sebastian Pacheco, Crismita Dmello, Catalina Lee-Chang, Kathleen McCortney, Alicia Steffens, Jordain Walshon, Martina Ott, Jun Wei, Anantha Marisetty, Irina Balyasnikova, Roger Stupp, Rimas V. Lukas, Jian Hu, Charles David James, Craig M. Horbinski, Maciej S. Lesniak, David M. Ashley, Waldemar Priebe, Leonidas C. Platanias, Michael A. Curran, Amy B. Heimberger

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Figure 5

Therapeutic effect of STING agonist 8803 in humanized glioma mouse model recapitulating human glioblastoma.

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Therapeutic effect of STING agonist 8803 in humanized glioma mouse model...
(A) Multiplexed sequential immunofluorescence images of the STING expression at baseline in humanized mouse brain implanted with U87 glioma cells and collected at endpoint. The right image represents a high magnification of the white box drawn in the left image. The white arrows highlight CD31+STING+ vessels and green arrows highlight the CD163+STING+ macrophages. DAPI (dark blue), GFAP (light blue), CD31 (cyan blue), STING (red), CD163 (green). Scale bars: 500 μm (left panel) and 50 μm (right panel). A higher magnification image of a CD163+STING+ cell is represented at the upper right quadrant of the right image (scale bar: 20 μm). (B) Humanized mice that underwent i.c. implantation of 112.5 × 103 (survival) or 90 × 103 (immune infiltrate analysis) human U87 glioma cells treated with PBS (n = 18), the moderately potent STING agonist MLRR-S2-CDA (n = 19), or 8803 (n = 12) on days 5, 10, and 15. The survival rate of the humanized mice was estimated by the Kaplan-Meier method. Control: median survival (MS): 26.5 days, MLRR-S2-CDA MS: 35 days, 8803 MS: 43.5 days. Statistics: control versus MLRR-S2-CDA log-rank ****P < 0.0001; control versus 8803 log-rank ****P < 0.0001. (C) Luxol Fast Blue demonstrating uniform staining without evidence of clearance that would be reflective of demyelination in the CNS in either the control or 8803-treated brains (×1.5 magnification). (D) Representative hematoxylin and eosin–stained coronal sections of mice at the survival endpoint demonstrating persistent glioma after treatment with 8803. Original magnification, ×1.25 (left and middle images) and ×10 (bottom right image). (E) Ex vivo Flow cytometric analysis of U87-infiltrating human immune cells using BD LSRFortessa X-30 prototype flow cytometer. MFI, mean fluorescence intensity; h, human; TAM, tumor-associated macrophage; Mono, monocyte; PMN, peripheral mononuclear cell; MDSC, myeloid-derived suppressor cell. (F) WT C57BL/6J mouse bone marrow–derived macrophages pretreated with IL-4 for 48 hours followed by STING agonist 8803 for the indicated times (24 hours and 48 hours). The markers were assessed via Cytek Aurora flow cytometer and the CD45+CD11b+ population was analyzed for the indicated markers. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001 by 2-tailed Student’s t test (E–F).