Cited by 152Cancer Immunotherapy and BiomarkersImmunotherapy and Immune ResponsesCancer, Hypoxia, and Metabolism

The DOI matches its Crossref record; 56 of the 58 references it cites were found in a registry or an index; none of the 22 sources its claims cite is checked for support yet.

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

Open access

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.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

Targeting HIF-1α with liposomal echinomycin (LEM) suppresses PD-L1 in the tumor microenvironment and reactivates antitumor immunity, while unexpectedly inducing PD-L1 in normal tissues via IFN-γ. This differential regulation potentiates anti–CTLA-4 therapy without the irAE exacerbation seen with anti–PD-1.

Key findings

  • LEM reduced PD-L1 on tumor cells and tumor-infiltrating myeloid cells (M-MDSCs, PMN-MDSCs, and CD11b+CD11c+ cells, ~90% of which were F4/80+ TAMs), increased IFN-γ+CD8+ (Tc1) and IFN-γ+CD4+ (Th1) TILs, and inhibited tumor growth in immunocompetent but less so in immunodeficient mice.
  • LEM potentiated anti–CTLA-4 (9D9) therapy in 4T1, E0771, and MC38 models, with efficacy comparable to anti–CTLA-4 plus anti–PD-1; optimal efficacy required CD8+, NK, and CD4+ cells, with CD8+ cells most critical.
  • In normal tissues, LEM induced PD-L1 in liver, kidney, and intestine by an IFN-γ–dependent mechanism; in CTLA4h/h-KI mice, LEM protected against ipilimumab-induced intestinal leakage, and adding anti–IFN-γ increased the frequency of mice with leakage from 7.7% to 20.0%.
  • Anti–PD-1 abrogated LEM’s protection against ipilimumab-induced GI irAEs, whereas LEM protected mice by increasing normal-tissue PD-L1; the paper notes dual checkpoint blockade causes severe irAEs in 50%–90% of patients depending on setting.

Methods

  • Syngeneic mouse tumor models: 4T1 and E0771 breast cancer and MC38 colon adenocarcinoma in BALB/c, C57BL/6, and NSG mice; genetic tools included shHif1a, shPdl1, and conditional Hif1a knockout in T cells.
  • Treatments: liposomal echinomycin (LEM) i.v. at 0.15–0.25 mg/kg; anti–mouse CTLA-4 (9D9), anti–PD-1 (RMP1-14), anti–IFN-γ (XMG1.2), and depleting CD4/CD8/NK antibodies; readouts included flow cytometry, immunofluorescence, histology, and FITC-dextran intestinal permeability.
  • GI irAE model: 10-day-old human CTLA4-knockin mice received ipilimumab i.p. on days 10, 13, 16, and 19; FITC-dextran assay on day 32. Statistics used t tests, 1-way/2-way ANOVA with Sidak’s post hoc test, and Pearson correlation in Prism 8, with P < 0.05 significant.

Limitations

  • Stated: adult tumor-bearing mice tolerated high-dose anti–CTLA-4 without significant irAEs, so the irAE studies relied on young CTLA4h/h-KI mice.
  • Stated: it is unclear whether LEM promotes Tc1 expansion in vivo by cell-intrinsic HIF-1α targeting or indirectly by reducing regulatory T cells.
  • Evident: all efficacy and toxicity data are preclinical mouse models; no human clinical outcomes or patient data are reported.

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Integrity signals

Registry

Crossref · 10.1172/jci150846

Cites

56 of 56 references verified0 citation errors · 0 not checkable

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Claims the paper makes

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  • It may state two separate claims as one. 30
  • Probably not a substantial claim. 15
43 of 43
  • The paper relies on this without support.

    Clinical development of echinomycin for solid tumors has met with minimal success.

    “However, clinical development of echinomycin for solid tumors has met with minimal success.”
  • The paper relies on this without support.

    The current approach that overcomes tumor evasion of host immunity also disables the immune tolerance checkpoint, leading to significant irAEs, particularly when used in conjunction with anti–CTLA-4 antibodies.

    “However, the current approach that overcomes tumor evasion of host immunity also disables the immune tolerance checkpoint, leading to significant irAEs, particularly when used in conjunction with anti–CTLA-4 antibodies.”
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Metadata

Authors
Bailey, C. M., Liu, Y., Liu, M., Du, X., Devenport, M., Zheng, P., Liu, Y., & Wang, Y.
Affiliations
University of Maryland, Baltimore (US)
Corresponding author
  • Liu, Yang
  • Wang, Yin
Venue
Journal of Clinical Investigation
Published
2022-05-02
Volume
132
Issue
9
ISSN
  • 0021-9738 (ISSN-L)
  • 1558-8238
OpenAlex
W4214881895
Cited by
151
References
58
Citations by year
2026: 34 · 2025: 45 · 2024: 38 · 2023: 24 · 2022: 10
FWCI
12.35
Type
journal article
Language
en
Open access
Locations
  • Journal of Clinical Investigation (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
Funders
National Institutes of Health (CA171972, CA183030, CA219150, CA227671)
Topics
  • Health Sciences › Medicine › Oncology › Cancer Immunotherapy and Biomarkers
  • Life Sciences › Immunology and Microbiology › Immunology › Immunotherapy and Immune Responses
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cancer Research › Cancer, Hypoxia, and Metabolism
Keywords
HIF-1α, PD-L1, immune evasion, tumor microenvironment, immune-related adverse events, CTLA-4, PD-1/PD-L1 immune checkpoint, echinomycin, interferon-gamma, tumor-infiltrating myeloid cells, tumor-infiltrating lymphocytes, cancer immunotherapy
MeSH terms
Animals, Echinomycin, Immune Tolerance, Neoplasms, Lymphocytes, Tumor-Infiltrating, Mice, Hypoxia-Inducible Factor 1, alpha Subunit, Immune Evasion, Tumor Microenvironment, B7-H1 Antigen

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