Targeting HIF-1α abrogates PD-L1–mediated immune evasion in tumor microenvironment but promotes tolerance in normal tissues
Christopher M. Bailey, … , Yang Liu, Yin Wang
Christopher M. Bailey, … , Yang Liu, Yin Wang
Published March 3, 2022
Citation Information: J Clin Invest. 2022;132(9):e150846. https://doi.org/10.1172/JCI150846.
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Research Article Therapeutics

Targeting HIF-1α abrogates PD-L1–mediated immune evasion in tumor microenvironment but promotes tolerance in normal tissues

Abstract

A combination of anti–CTLA-4 plus anti–PD-1/PD-L1 is the most effective cancer immunotherapy but causes high incidence of immune-related adverse events (irAEs). Here we report that targeting of HIF-1α suppressed PD-L1 expression on tumor cells and tumor-infiltrating myeloid cells, but unexpectedly induced PD-L1 in normal tissues by an IFN-γ–dependent mechanism. Targeting the HIF-1α/PD-L1 axis in tumor cells reactivated tumor-infiltrating lymphocytes and caused tumor rejection. The HIF-1α inhibitor echinomycin potentiated the cancer immunotherapeutic effects of anti–CTLA-4 therapy, with efficacy comparable to that of anti–CTLA-4 plus anti–PD-1 antibodies. However, while anti–PD-1 exacerbated irAEs triggered by ipilimumab, echinomycin protected mice against irAEs by increasing PD-L1 levels in normal tissues. Our data suggest that targeting HIF-1α fortifies the immune tolerance function of the PD-1/PD-L1 checkpoint in normal tissues but abrogates its immune evasion function in the tumor microenvironment to achieve safer and more effective immunotherapy.

Authors

Christopher M. Bailey, Yan Liu, Mingyue Liu, Xuexiang Du, Martin Devenport, Pan Zheng, Yang Liu, Yin Wang

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Figure 7

Echinomycin stimulates PD-L1 expression in irAE target organs to limit the infiltration of T cells caused by anti–CTLA-4 mAbs by an IFN-γ–dependent mechanism.

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Echinomycin stimulates PD-L1 expression in irAE target organs to limit t...
E0771 cells (0.5 × 106) were transplanted into C57BL/6 mice (day 0), which were divided into 6 treatment groups (n = 5/group): vehicle, echinomycin (LEM), anti–CTLA-4 (9D9), 9D9 plus LEM, 9D9 plus LEM plus anti–IFN-γ (XMG1.2), and 9D9 plus anti–PD-1 (RMP1-14). LEM (0.25 mg/kg) or mAbs (0.2 mg/mouse/dose) were given on days 6, 8, 10, and 12. On day 14, the mice were perfused. Dissociated spleens were stimulated for 4 hours with PMA plus ionomycin and GolgiStop prior to flow cytometry. Liver and kidney tissues were fixed and immunofluorescently stained for indicated markers and with DAPI (blue). (A) PD-L1 expression in the tumor-bearing mice treated with different therapies. Representative PD-L1 immunofluorescence staining shown for kidney and liver tissues from indicated treatment groups. Scale bars: 20 μm. (B–D) T cell infiltration in the liver and kidney of tumor-bearing mice. (B) Representative CD3 immunofluorescence staining depicting T cell infiltration in kidney and liver tissues. Scale bars: 50 μm. (C and D) T cell infiltration was scored (scale of 0–4) in the kidney (C) and liver (D) tissues as follows: 0, normal/none; 1, minimal; 2, mild; 3, moderate; 4, severe. (E) Frequency of splenic T cells (gated on live CD45+CD3+CD8+CD4– singlets) among total hematopoietic cells (gated on live CD45+ singlets). (F) Frequency of splenic Tc1 cells among CD8+ T cells (gated on live CD45+CD3+CD8+CD4– singlets). (G) Frequency of splenic Th1 cells among CD4+ T cells (gated on live CD45+CD3+CD8–CD4+ singlets). (H) CD3 and cleaved caspase 3 staining in kidney and liver. Representative immunofluorescence images shown for kidney (upper) and liver tissues (lower) of mice that received 9D9 or 9D9 plus LEM. All data are representative of at least 2 independent experiments. Scale bar: 20 μm. In C–G, data are presented as the mean ± SEM, with each dot representing an individual mouse, and were analyzed by 1-way ANOVA with Sidak’s post hoc test. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.