Cited by 200Cancer Immunotherapy and BiomarkersCancer, Hypoxia, and MetabolismImmune cells in cancer

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Hypoxia induces HIF1α-dependent epigenetic vulnerability in triple negative breast cancer to confer immune effector dysfunction and resistance to anti-PD-1 immunotherapy

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Abstract

The hypoxic tumor microenvironment has been implicated in immune escape, but the underlying mechanism remains elusive. Using an in vitro culture system modeling human T cell dysfunction and exhaustion in triple-negative breast cancer (TNBC), we find that hypoxia suppresses immune effector gene expression, including in T and NK cells, resulting in immune effector cell dysfunction and resistance to immunotherapy. We demonstrate that hypoxia-induced factor 1α (HIF1α) interaction with HDAC1 and concurrent PRC2 dependency causes chromatin remolding resulting in epigenetic suppression of effector genes and subsequent immune dysfunction. Targeting HIF1α and the associated epigenetic machinery can reverse the immune effector dysfunction and overcome resistance to PD-1 blockade, as demonstrated both in vitro and in vivo using syngeneic and humanized mice models. These findings identify a HIF1α-mediated epigenetic mechanism in immune dysfunction and provide a potential strategy to overcome immune resistance in TNBC.

Overview

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TL;DR

Hypoxia in triple-negative breast cancer suppresses T and NK effector gene expression via HIF1α-dependent recruitment of HDAC1 and pre-existing PRC2, producing chromatin remodeling and resistance to anti-PD-1 therapy. Targeting HIF1α or the associated epigenetic machinery restores immune effector function and sensitizes TNBC to PD-1 blockade in vitro and in mouse models.

Key findings

  • In TCGA basal TNBC samples (n = 98 in Fig. 1a), hypoxia gene signature expression was inversely correlated with immune effector genes (IFNG, TNF, GZMB, PRF1), IFNγ-responsive genes, and TIL-associated genes; in human TNBC samples (n = 30), HIF1α-high tumor areas had reduced CD8+ T cell infiltration and IFNγ expression.
  • Hypoxia (1% O2) suppressed IFNγ, TNFα, and granzyme B in CD8+ T cells and NK cells, and induced TIM-3/TIGIT; hypoxia plus TNBC coculture increased PD-1+TIM-3+ double-positive CD8+ T cells to 30–40% versus 10–20% in resting T cells.
  • Hypoxia increased HIF1α and HDAC1 occupancy at IFNG and TNF promoters, reduced H3K27ac, and increased H3K27me3; HIF1α co-immunoprecipitated with HDAC1, and HDAC1 also interacted with SUZ12. HDAC inhibitor entinostat, EZH2 inhibitor EPZ6438, HIF1α inhibitors PX478/digoxin, or CRISPR depletion of HDAC1/EZH2 restored effector expression.
  • In 4T1 syngeneic and humanized NIKO/LM2 mouse models, anti-PD-1 alone had minimal effect, but anti-PD-1 combined with PX478 or entinostat induced tumor regression, suppressed lung metastasis, and improved survival; depletion of T or NK cells largely abolished combination efficacy.

Methods

  • Human T and NK cells were isolated from healthy donor PBMC, expanded, and cultured under normoxia (20% O2) or hypoxia (1% O2), alone or cocultured with TNBC lines BT549, MDA-MB-231, or MDA-MB-231-LM2; assays included RNA-seq, flow cytometry, RT-qPCR, ChIP-qPCR, co-immunoprecipitation, CRISPR knockdown, and luciferase-based cytotoxicity.
  • TCGA breast cancer data were analyzed by PAM50 subtype (basal/TNBC n = 98; HER2+ n = 58; Luminal A n = 231; Luminal B n = 129); immunofluorescence used human TNBC samples (n = 30) and mouse 4T1 tumors.
  • In vivo work used BALB/c mice bearing orthotopic 4T1-Luc tumors and humanized NOD/SCID/IL2Rg−/− (NIKO) mice reconstituted with human CD34+ cells and engrafted with MDA-MB-231-LM2; treatments included anti-PD-1/Keytruda with PX478, entinostat, or EPZ6438. Statistics used ANOVA, t-tests, and log-rank tests; RNA-seq DEG thresholds were |logFC| > 1 and adjusted P < 0.01.

Limitations

  • The paper states that PX478 and epigenetic drugs have additional effects on other tumor microenvironment elements such as myeloid cells and macrophages, and that EPZ6438 could not achieve satisfactory solubility in different formulations, likely explaining its weaker in vivo effects.
  • The paper notes that HIF1α-independent induction of TIM-3 and TIGIT remains to be explored as a possible additional strategy to prevent T cell exhaustion.
  • Evident from the text: the mechanistic evidence relies heavily on in vitro healthy-donor human immune cells and mouse/humanized models, with no clinical trial validation; TCGA findings are correlative, and the 1% O2 system may not fully capture heterogeneous tumor hypoxia.

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Crossref · 10.1038/s41467-022-31764-9

Cites

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Statistics

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Figures

Fig. 1 Hypoxia is associated with immune exclusion in human and mouse triple-negative breast cancer (TNBC). a Heatmap showing Pearson’s correlation between hypoxic signature genes expression and immune-related genes expression in basal TNBC samples (n = 98) in TCGA dataset. b Scatter plots (upper panel) and Pearson’s correlation coefficients (lower panel) showing the expression of hypoxic gene signatures and immune-related genes in breast cancers in TCGA dataset (Basal, n = 98; HER2, n = 58; Luminal A, n = 231; Luminal B, n = 129). Regression lines with a 95% confidence interval (gray fill) are shown in the scatter plots. c Images of fluorescent staining of human TNBC samples. Scale bar, 50 µm. Data were representative of 30 independent experiments. d Quantification of infiltrating IFNγ+ CD8+ T cell number in HIF1α− and HIF1α+ regions of human TNBC sample (n = 30). P values were determined with paired two-tailed t-test. e Correlation between infiltrating IFNγ+ CD8+ T cell count and HIF1α fluorescent intensity in human TNBC samples (n = 30). The simple linear regression R2 and P values (two-tailed) are calculated. Dot plot is shown with regression line and 95% confidence interval. f Representative images of fluorescent staining of mouse 4T1 tumor samples. Scale bar, 50 µm. Data represents three independent experiments. g Flow cytometry (left panel) demonstrating the gating strategy of activated-PIM high (H) and activated-PIM low (L) populations in living cells dissociated from 4T1 tumors. The CD8+ T cell percentage and IFNγ expression in CD8+ T cells was quantified (right panel, n = 6). Data were presented as box and whiskers, with median value and whiskers of minimum and maximum values. P values were determined with an unpaired two-tailed t-test. h Kaplan–Meier overall survival (OS) and distant metastasis-free survival (DMFS) analysis of the indicated gene signatures in TNBC patients. The publicly available data used in Fig. 1a, b are available in the TCGA database under accession code BRCA.exp.547.med.txt [https://gdc.cancer.gov/about-data/publications/brca_2012]. The publicly available data used in h are available in the KM-Plotter-Breast Cancer [https://kmplot.com/analysis/index.php?p=service&cancer=breast]. For the remaining data, source data are provided in Source Data file.
Fig. 1 Hypoxia is associated with immune exclusion in human and mouse triple-negative breast cancer (TNBC). a Heatmap showing Pearson’s correlation between hypoxic signature genes expression and immune-related genes expression in basal TNBC samples (n = 98) in TCGA dataset. b Scatter plots (upper panel) and Pearson’s correlation coefficients (lower panel) showing the expression of hypoxic gene signatures and immune-related genes in breast cancers in TCGA dataset (Basal, n = 98; HER2, n = 58; Luminal A, n = 231; Luminal B, n = 129). Regression lines with a 95% confidence interval (gray fill) are shown in the scatter plots. c Images of fluorescent staining of human TNBC samples. Scale bar, 50 µm. Data were representative of 30 independent experiments. d Quantification of infiltrating IFNγ+ CD8+ T cell number in HIF1α− and HIF1α+ regions of human TNBC sample (n = 30). P values were determined with paired two-tailed t-test. e Correlation between infiltrating IFNγ+ CD8+ T cell count and HIF1α fluorescent intensity in human TNBC samples (n = 30). The simple linear regression R2 and P values (two-tailed) are calculated. Dot plot is shown with regression line and 95% confidence interval. f Representative images of fluorescent staining of mouse 4T1 tumor samples. Scale bar, 50 µm. Data represents three independent experiments. g Flow cytometry (left panel) demonstrating the gating strategy of activated-PIM high (H) and activated-PIM low (L) populations in living cells dissociated from 4T1 tumors. The CD8+ T cell percentage and IFNγ expression in CD8+ T cells was quantified (right panel, n = 6). Data were presented as box and whiskers, with median value and whiskers of minimum and maximum values. P values were determined with an unpaired two-tailed t-test. h Kaplan–Meier overall survival (OS) and distant metastasis-free survival (DMFS) analysis of the indicated gene signatures in TNBC patients. The publicly available data used in Fig. 1a, b are available in the TCGA database under accession code BRCA.exp.547.med.txt [https://gdc.cancer.gov/about-data/publications/brca_2012]. The publicly available data used in h are available in the KM-Plotter-Breast Cancer [https://kmplot.com/analysis/index.php?p=service&cancer=breast]. For the remaining data, source data are provided in Source Data file.CC BY · PubMed Central
Fig. 2 Hypoxia induces dysfunction and terminal exhaustion of human T cells. a Schematic graph demonstrating the coculture model. b Representative flow cytograms (upper panel) gated from human pan-T cell culture and quantification (lower panel, n = 3) of differentiated CD8+ T cell subtypes: Tn (naïve T cells), Tcm (central memory T cells), Tem (effector memory T cells), Teff (effector T cells). c Schematic graph demonstrating the normoxia (20% O2) and hypoxia (1% O2) culture condition of T cells coculturing with human TNBC cell line. d Heatmap of the differentially expressed genes (DEGs) in hypoxic cultured human T cells compared to normoxia group. DEGs were identified in edgeR (|logFC| > 1, adjusted P < 0.01). P values were adjusted using Benjamini–Hochberg method in edgeR. DEGs identified in the indicated GO gene clusters are marked in the heatmap. e GSEA analysis of human T cells in hypoxic versus normoxic conditions. Analysis was based on ranked logFC from edgeR. FDR and adjusted p value are shown in the graph. P values were adjusted using Benjamini–Hochberg method in GSEA analysis. f Flow cytometry quantifications of immune effector molecules and exhaustion markers in CD8+ T cells gated from human pan-T cells cultured under the indicated conditions (n = 4). g Representative flow cytograms of PD-1 and TIM-3 expression in CD8+ T cells gated from human pan-T cells culture. h Flow cytometric quantification of terminally exhausted T cells (PD-1+ TIM-3+) in CD8+ T cells gated from human pan-T cells culture (n = 3). i Flow cytometric quantification of proliferating cells (Ki76+) in CD8+ and CD4+ T cells gated from human T cells cocultured with TNBC (n = 3). All flow cytometry data (b, f, h, and i) are presented as the mean ± SD of samples from three to four donors. For all flow cytometry data, P values were determined by one-way ANOVA (f, h) or two-way ANOVA (b) with Turkey’s test, or paired two-tailed t-test (i). Raw RNA-seq data is available in the GEO database with accession number GSE179885. For the remaining data, source data are provided in Source Data file.
Fig. 2 Hypoxia induces dysfunction and terminal exhaustion of human T cells. a Schematic graph demonstrating the coculture model. b Representative flow cytograms (upper panel) gated from human pan-T cell culture and quantification (lower panel, n = 3) of differentiated CD8+ T cell subtypes: Tn (naïve T cells), Tcm (central memory T cells), Tem (effector memory T cells), Teff (effector T cells). c Schematic graph demonstrating the normoxia (20% O2) and hypoxia (1% O2) culture condition of T cells coculturing with human TNBC cell line. d Heatmap of the differentially expressed genes (DEGs) in hypoxic cultured human T cells compared to normoxia group. DEGs were identified in edgeR (|logFC| > 1, adjusted P < 0.01). P values were adjusted using Benjamini–Hochberg method in edgeR. DEGs identified in the indicated GO gene clusters are marked in the heatmap. e GSEA analysis of human T cells in hypoxic versus normoxic conditions. Analysis was based on ranked logFC from edgeR. FDR and adjusted p value are shown in the graph. P values were adjusted using Benjamini–Hochberg method in GSEA analysis. f Flow cytometry quantifications of immune effector molecules and exhaustion markers in CD8+ T cells gated from human pan-T cells cultured under the indicated conditions (n = 4). g Representative flow cytograms of PD-1 and TIM-3 expression in CD8+ T cells gated from human pan-T cells culture. h Flow cytometric quantification of terminally exhausted T cells (PD-1+ TIM-3+) in CD8+ T cells gated from human pan-T cells culture (n = 3). i Flow cytometric quantification of proliferating cells (Ki76+) in CD8+ and CD4+ T cells gated from human T cells cocultured with TNBC (n = 3). All flow cytometry data (b, f, h, and i) are presented as the mean ± SD of samples from three to four donors. For all flow cytometry data, P values were determined by one-way ANOVA (f, h) or two-way ANOVA (b) with Turkey’s test, or paired two-tailed t-test (i). Raw RNA-seq data is available in the GEO database with accession number GSE179885. For the remaining data, source data are provided in Source Data file.CC BY · PubMed Central
Fig. 3 Hypoxia induces epigenetic inactivation of immune effector expression. a RT-qPCR analysis assessing IFNG expression in T/NK cells in an epigenetic-drug screening. Both T cells and NK cells were cultured under 1% O2 with indicated treatments. Data were presented as the log2 fold change of IFNG mRNA level normalized to vehicle control, mean ± SD of technical triplicates, representative of two independent experiments (n = 2). b, c Representative histograms (left panel) and flow cytometric quantifications (right panel) of IFNγ expression in human CD8+ T cells (b n = 4) and NK cells (c n = 3) with indicated treatments. Quantification data were presented as the mean ± SD of samples from three to four donors. P values were determined by two-way ANOVA with Turkey’s test. d ChIP-qPCR analysis of HDAC1, HDAC2, HDAC3, EZH2, and SUZ12 occupancy on IFNG promoter of human T cells. Four primers were designed to span the promoters of IFNG, with P1 at −1448 to −1354b, P2 at −707 to −628b, P3 at −257 to −171b, P4 at +350 to +461b, relative to TSS. For ChIP analysis of EZH2 and SUZ12 occupancy, RPL30 serves as the negative control and CCND2 as the positive control. e, f ChIP-qPCR analysis of H3K27ac and H3K27me3 enrichment on IFNG promoter of human T cells under indicated conditions. All ChIP-qPCR data (d–f) are presented as fold enrichment relative to IgG and expressed as mean ± SD of technical triplicates, representative of two independent experiments (n = 2). For ChIP-qPCR data of d, e, statistics were performed to analyze bindings of indicated markers across different sites in IFNG promoter (RPL30 and CCND2 excluded) between hypoxia and normoxia. P values were determined by two-way ANOVA analysis. g RT-qPCR analysis of human T cell with indicated gene knockdown. Data were presented as the fold change of mRNA level normalized to the control group under normoxia (1% O2), mean ± SD of technical triplicates, representative of two independent experiments (n = 2). Source data are provided as a source data file.
Fig. 3 Hypoxia induces epigenetic inactivation of immune effector expression. a RT-qPCR analysis assessing IFNG expression in T/NK cells in an epigenetic-drug screening. Both T cells and NK cells were cultured under 1% O2 with indicated treatments. Data were presented as the log2 fold change of IFNG mRNA level normalized to vehicle control, mean ± SD of technical triplicates, representative of two independent experiments (n = 2). b, c Representative histograms (left panel) and flow cytometric quantifications (right panel) of IFNγ expression in human CD8+ T cells (b n = 4) and NK cells (c n = 3) with indicated treatments. Quantification data were presented as the mean ± SD of samples from three to four donors. P values were determined by two-way ANOVA with Turkey’s test. d ChIP-qPCR analysis of HDAC1, HDAC2, HDAC3, EZH2, and SUZ12 occupancy on IFNG promoter of human T cells. Four primers were designed to span the promoters of IFNG, with P1 at −1448 to −1354b, P2 at −707 to −628b, P3 at −257 to −171b, P4 at +350 to +461b, relative to TSS. For ChIP analysis of EZH2 and SUZ12 occupancy, RPL30 serves as the negative control and CCND2 as the positive control. e, f ChIP-qPCR analysis of H3K27ac and H3K27me3 enrichment on IFNG promoter of human T cells under indicated conditions. All ChIP-qPCR data (d–f) are presented as fold enrichment relative to IgG and expressed as mean ± SD of technical triplicates, representative of two independent experiments (n = 2). For ChIP-qPCR data of d, e, statistics were performed to analyze bindings of indicated markers across different sites in IFNG promoter (RPL30 and CCND2 excluded) between hypoxia and normoxia. P values were determined by two-way ANOVA analysis. g RT-qPCR analysis of human T cell with indicated gene knockdown. Data were presented as the fold change of mRNA level normalized to the control group under normoxia (1% O2), mean ± SD of technical triplicates, representative of two independent experiments (n = 2). Source data are provided as a source data file.CC BY · PubMed Central
Fig. 4 Hypoxia-induced epigenetic inactivation of effector expression is HIF1α-dependent. a ChIP-qPCR analysis of HIF1α and HIF2α occupancy on IFNG promoter in human T cells. VEGFA served as a positive control. b Co-immunoprecipitation shows the physical interaction between HDAC1 and HIF1α, and the interaction between HDAC1 and SUZ12 in human T cells. Data is representative of two independent experiments (n = 2). c Representative western blot images (n = 2) to demonstrate knockdown of HIF1α in human T cells. d ChIP-qPCR analysis of HDAC1 occupancy on IFNG promoter in human T cells. e ChIP-qPCR analysis of H3K27ac and H3K27me3 enrichment on IFNG promoter in human T cells with indicated treatments. All ChIP-qPCR data (a, d, e) are presented as fold enrichment relative to IgG and expressed as mean ± SD of technical triplicates, representative of two independent experiments (n = 2). For ChIP-qPCR data of a, statistics were performed to analyze bindings of indicated markers across different sites in IFNG promoter (VEGFA excluded) between hypoxia and normoxia. P values were determined by two-way ANOVA analysis. f Flow cytometric quantifications of IFNγ in CD8+ T cells gated from human pan-T cells cultured under the indicated conditions. Data were presented as the mean ± SD of three independent experiments (n = 3). P values were determined by one-way ANOVA with Turkey’s test. g Representative western blot images (n = 2) to demonstrate the inhibition of HIF1α level by indicated compounds in human T cells. h Representative histograms (left panel) and flow cytometric quantifications (right panel) of IFNγ expression in human CD8+ T cells with indicated treatments. Quantification data were presented as the mean ± SD of samples from four donors (n = 4). P values were determined by two-way ANOVA with Turkey’s test. Source data are provided as a source data file.
Fig. 4 Hypoxia-induced epigenetic inactivation of effector expression is HIF1α-dependent. a ChIP-qPCR analysis of HIF1α and HIF2α occupancy on IFNG promoter in human T cells. VEGFA served as a positive control. b Co-immunoprecipitation shows the physical interaction between HDAC1 and HIF1α, and the interaction between HDAC1 and SUZ12 in human T cells. Data is representative of two independent experiments (n = 2). c Representative western blot images (n = 2) to demonstrate knockdown of HIF1α in human T cells. d ChIP-qPCR analysis of HDAC1 occupancy on IFNG promoter in human T cells. e ChIP-qPCR analysis of H3K27ac and H3K27me3 enrichment on IFNG promoter in human T cells with indicated treatments. All ChIP-qPCR data (a, d, e) are presented as fold enrichment relative to IgG and expressed as mean ± SD of technical triplicates, representative of two independent experiments (n = 2). For ChIP-qPCR data of a, statistics were performed to analyze bindings of indicated markers across different sites in IFNG promoter (VEGFA excluded) between hypoxia and normoxia. P values were determined by two-way ANOVA analysis. f Flow cytometric quantifications of IFNγ in CD8+ T cells gated from human pan-T cells cultured under the indicated conditions. Data were presented as the mean ± SD of three independent experiments (n = 3). P values were determined by one-way ANOVA with Turkey’s test. g Representative western blot images (n = 2) to demonstrate the inhibition of HIF1α level by indicated compounds in human T cells. h Representative histograms (left panel) and flow cytometric quantifications (right panel) of IFNγ expression in human CD8+ T cells with indicated treatments. Quantification data were presented as the mean ± SD of samples from four donors (n = 4). P values were determined by two-way ANOVA with Turkey’s test. Source data are provided as a source data file.CC BY · PubMed Central
Fig. 5 Hypoxia dampens immune cytotoxicity, weakens interferon signaling, and induces resistance to PD-1 blockade. a Cell lysis of TNBC cells cocultured with human T cells from two different healthy donors. Human T cells were stimulated with TNBC cell lysate-primed DC cells. Data were presented as mean ± SD of three independent experiments (n = 3). P values were determined by two-way ANOVA. b Western blot analysis of IFNγ–regulated proteins in TNBC cells cocultured with human T cells. Data were representative of two independent experiments (n = 2). c Cell lysis of TNBC cells cocultured with human T cells. Human T cells were stimulated with TNBC cell lysate-primed DC cells and pretreated with indicated compounds. Data presented as mean ± SD of three independent experiments (n = 3). P values were determined by one-way ANOVA with Dunnett’s test. d Western blot analysis of IFNγ–regulated proteins in TNBC cells cocultured with human T cells. Human T cells were stimulated with TNBC cell lysate-primed DC cells and pretreated with indicated compounds. Data were representative of two independent experiments (n = 2). e Cell lysis of TNBC cells cocultured with human T cells. Data were presented as mean ± SD of three independent experiments (n = 3). P values were determined by two-way ANOVA with Dunnett’s test. f Flow cytometric quantifications of immune effector molecules in human CD8+ T cells cultured under the indicated conditions. Data were presented as the mean ± SD of samples from three donors (n = 3). P values were determined by two-way ANOVA with Turkey’s test. Source data are provided as a source data file.
Fig. 5 Hypoxia dampens immune cytotoxicity, weakens interferon signaling, and induces resistance to PD-1 blockade. a Cell lysis of TNBC cells cocultured with human T cells from two different healthy donors. Human T cells were stimulated with TNBC cell lysate-primed DC cells. Data were presented as mean ± SD of three independent experiments (n = 3). P values were determined by two-way ANOVA. b Western blot analysis of IFNγ–regulated proteins in TNBC cells cocultured with human T cells. Data were representative of two independent experiments (n = 2). c Cell lysis of TNBC cells cocultured with human T cells. Human T cells were stimulated with TNBC cell lysate-primed DC cells and pretreated with indicated compounds. Data presented as mean ± SD of three independent experiments (n = 3). P values were determined by one-way ANOVA with Dunnett’s test. d Western blot analysis of IFNγ–regulated proteins in TNBC cells cocultured with human T cells. Human T cells were stimulated with TNBC cell lysate-primed DC cells and pretreated with indicated compounds. Data were representative of two independent experiments (n = 2). e Cell lysis of TNBC cells cocultured with human T cells. Data were presented as mean ± SD of three independent experiments (n = 3). P values were determined by two-way ANOVA with Dunnett’s test. f Flow cytometric quantifications of immune effector molecules in human CD8+ T cells cultured under the indicated conditions. Data were presented as the mean ± SD of samples from three donors (n = 3). P values were determined by two-way ANOVA with Turkey’s test. Source data are provided as a source data file.CC BY · PubMed Central
Fig. 6 Pharmacological inhibition of HIF1α and associated epigenetic events sensitizes PD-1 blockade in a syngeneic mouse model. a Change of 4T1 tumor volume from baseline in BALB/c mice at Day 16 of drug treatments. N = 8. b Lung metastasis of BALB/c mice bearing 4T1 at Day 30. Left panel, representative bioluminescence images. Right panel, quantification of lung metastasis. Control, n = 5; αPD-1, n = 6; n = 8 for ENT and ENT + αPD-1; n = 7 for PX478 and PX478 + αPD-1. c Kaplan–Meier survival curve for 4T1-bearing mice. Control, n = 8; αPD-1, n = 7; ENT, n = 8; ENT + αPD-1, n = 7; n = 6 for PX478 and PX478 + αPD-1. P values were determined by Mantel–Cox test. d 4T1 tumor volume in NK-depleted mice (n = 16 for control and ENT + αPD-1; PX478 + αPD-1, n = 10), T-depleted mice (n = 16 for control and ENT + αPD-1; PX478 + αPD-1, n = 12) and normal mice (control, n = 16; ENT + αPD-1, n = 14; PX478 + αPD-1, n = 10), at Day 15 of treatments. e Lung metastasis of NK-depleted mice (control, n = 8; ENT + αPD-1, n = 7; PX478 + αPD-1, n = 5), T-depleted mice (n = 7 for control and ENT + αPD-1; PX478 + αPD-1, n = 5) and normal mice (n = 8 for control and ENT + αPD-1; PX478 + αPD-1, n = 6) at Day 15/30. f Flow cytometric analysis of 4T1 tumors. N = 6. g Flow analysis on HIF1α expression in cells dissociated from 4T1 tumors. N = 6. h, i Immunofluorescence analysis of 4T1 tumor slides. Representative images (h scale bar 20 µm) and quantifications (i). N = 6. j, k Flow cytometric analysis of 4T1 tumors, n = 5 for ENT + αPD-1, n = 6 for other groups. Data of f, g, j, k, i are presented as box and whiskers, with median value and whiskers of minimum and maximum values. Data of a, b, d, e were presented as mean ± SD. P values were determined by one-way (a, b, f, g) or two-way (d, e, i, j, k) ANOVA with Turkey’s test. Source data are provided as a source data file.
Fig. 6 Pharmacological inhibition of HIF1α and associated epigenetic events sensitizes PD-1 blockade in a syngeneic mouse model. a Change of 4T1 tumor volume from baseline in BALB/c mice at Day 16 of drug treatments. N = 8. b Lung metastasis of BALB/c mice bearing 4T1 at Day 30. Left panel, representative bioluminescence images. Right panel, quantification of lung metastasis. Control, n = 5; αPD-1, n = 6; n = 8 for ENT and ENT + αPD-1; n = 7 for PX478 and PX478 + αPD-1. c Kaplan–Meier survival curve for 4T1-bearing mice. Control, n = 8; αPD-1, n = 7; ENT, n = 8; ENT + αPD-1, n = 7; n = 6 for PX478 and PX478 + αPD-1. P values were determined by Mantel–Cox test. d 4T1 tumor volume in NK-depleted mice (n = 16 for control and ENT + αPD-1; PX478 + αPD-1, n = 10), T-depleted mice (n = 16 for control and ENT + αPD-1; PX478 + αPD-1, n = 12) and normal mice (control, n = 16; ENT + αPD-1, n = 14; PX478 + αPD-1, n = 10), at Day 15 of treatments. e Lung metastasis of NK-depleted mice (control, n = 8; ENT + αPD-1, n = 7; PX478 + αPD-1, n = 5), T-depleted mice (n = 7 for control and ENT + αPD-1; PX478 + αPD-1, n = 5) and normal mice (n = 8 for control and ENT + αPD-1; PX478 + αPD-1, n = 6) at Day 15/30. f Flow cytometric analysis of 4T1 tumors. N = 6. g Flow analysis on HIF1α expression in cells dissociated from 4T1 tumors. N = 6. h, i Immunofluorescence analysis of 4T1 tumor slides. Representative images (h scale bar 20 µm) and quantifications (i). N = 6. j, k Flow cytometric analysis of 4T1 tumors, n = 5 for ENT + αPD-1, n = 6 for other groups. Data of f, g, j, k, i are presented as box and whiskers, with median value and whiskers of minimum and maximum values. Data of a, b, d, e were presented as mean ± SD. P values were determined by one-way (a, b, f, g) or two-way (d, e, i, j, k) ANOVA with Turkey’s test. Source data are provided as a source data file.CC BY · PubMed Central
Fig. 7 Pharmacological inhibition of HIF1α and associated epigenetic events sensitizes PD-1 blockade in a humanized mouse model. a Schematic diagram showing the establishment of humanized mice (humice) with human immune system reconstituted in NIKO mice. The presence of human CD45+ cells, NK cells, CD4+ and CD8+ T cells in the mice’s peripheral system was validated by flow cytometry. b Primary LM2 tumor size in humice (control, n = 14; Keytruda, n = 14; ENT, n = 12; PX478, n = 14; ENT + Keytruda, n = 16; PX478 + Keytruda, n = 16) and NIKO mice (control, n = 10; ENT + Keytruda, n = 10; PX478 + Keytruda, n = 10), at Day 21 of treatments. c Lung metastasis of humice (control, n = 6; Keytruda, n = 6; ENT, n = 6; PX478, n = 6; ENT + Keytruda, n = 7; PX478 + Keytruda, n = 7) and NIKO mice (control, n = 5; ENT + Keytruda, n = 5; PX478 + Keytruda, n = 5) bearing LM2 tumors at Day 35 assessed by bioluminescence (BLI) measurement. d Representative bioluminescence (BLI) images showing the lung metastasis of humice and NIKO mice. e Flow cytometric analysis of LM2 tumors harvested from humanized mice. IFNγ, TNFα, and granzyme B expression was examined in tumor-infiltrating human CD8+ T cells and NK cells. N = 5 for each group. f Flow cytometry analysis of LM2 tumors harvested from humanized mice. Expressions of human PD-L1 and PD-L2 were examined in total living cells dissociated from LM2 tumors. N = 5 for each group. Quantification data of flow cytometry (e, f) are presented as a box and whiskers, with median values and whiskers of minimum and maximum values. Data for b and c were presented as mean ± SD. P values were determined by one-way (e, f) or two-way (b, c) ANOVA with Turkey’s test. Source data are provided as a source data file.
Fig. 7 Pharmacological inhibition of HIF1α and associated epigenetic events sensitizes PD-1 blockade in a humanized mouse model. a Schematic diagram showing the establishment of humanized mice (humice) with human immune system reconstituted in NIKO mice. The presence of human CD45+ cells, NK cells, CD4+ and CD8+ T cells in the mice’s peripheral system was validated by flow cytometry. b Primary LM2 tumor size in humice (control, n = 14; Keytruda, n = 14; ENT, n = 12; PX478, n = 14; ENT + Keytruda, n = 16; PX478 + Keytruda, n = 16) and NIKO mice (control, n = 10; ENT + Keytruda, n = 10; PX478 + Keytruda, n = 10), at Day 21 of treatments. c Lung metastasis of humice (control, n = 6; Keytruda, n = 6; ENT, n = 6; PX478, n = 6; ENT + Keytruda, n = 7; PX478 + Keytruda, n = 7) and NIKO mice (control, n = 5; ENT + Keytruda, n = 5; PX478 + Keytruda, n = 5) bearing LM2 tumors at Day 35 assessed by bioluminescence (BLI) measurement. d Representative bioluminescence (BLI) images showing the lung metastasis of humice and NIKO mice. e Flow cytometric analysis of LM2 tumors harvested from humanized mice. IFNγ, TNFα, and granzyme B expression was examined in tumor-infiltrating human CD8+ T cells and NK cells. N = 5 for each group. f Flow cytometry analysis of LM2 tumors harvested from humanized mice. Expressions of human PD-L1 and PD-L2 were examined in total living cells dissociated from LM2 tumors. N = 5 for each group. Quantification data of flow cytometry (e, f) are presented as a box and whiskers, with median values and whiskers of minimum and maximum values. Data for b and c were presented as mean ± SD. P values were determined by one-way (e, f) or two-way (b, c) ANOVA with Turkey’s test. Source data are provided as a source data file.CC BY · PubMed Central

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  • The paper relies on this without support.

    The in vitro culture system models human T cell dysfunction and exhaustion in TNBC.

    “Using an in vitro culture system modeling human T cell dysfunction and exhaustion in triple-negative breast cancer (TNBC)”
  • The paper relies on this without support.

    The fundamental mechanism governing tumor immune resistance remains unanswered.

    “However, the fundamental mechanism governing tumor immune resistance remains unanswered.”
  • The paper relies on this without support.

    Inhibition of IFNγ production and interferon response including PD-L1 is expected to induce resistance to PD-1/PD-L1 blockade.

    “Inhibition of IFNγ production and interferon response including PD-L1 is expected to induce resistance to the PD-1/PD-L1 blockade.”
  • The paper relies on this without support.

    The role of hypoxia in modulating cancer immunity and the corresponding mechanism remains unclear.

    “but its role in modulating cancer immunity and the corresponding mechanism remains unclear.”
  • The authors state this as an assumption.

    PX478 and epigenetic drugs also have additional effects on other elements such as myeloid cells and macrophages in the tumor microenvironment.

    “Admittedly, there is no doubt that PX478 and epigenetic drugs also have additional effects on other elements such as myeloid cells and macrophages in the tumor microenvironment.”
  • The paper relies on this without support.

    Hypoxia is a common trait for solid tumors.

    “given that hypoxia is a common trait for solid tumors”
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Metadata

Authors
Ma, S., Zhao, Y., Lee, W. C., Ong, L.-T., Lee, P. L., Jiang, Z., Oguz, G., Niu, Z., Liu, M., Goh, J. Y., Wang, W., Bustos, M. A., Ehmsen, S., Ramasamy, A., Hoon, D. S. B., Ditzel, H. J., Tan, E. Y., Chen, Q., & Yu, Q.
Affiliations
  • Agency for Science, Technology and Research (SG)
  • Sixth Affiliated Hospital of Sun Yat-sen University (CN)
  • Odense University Hospital (DK)
  • University of Southern Denmark (DK)
  • Tan Tock Seng Hospital (SG)
Corresponding author
  • Chen, Qingfeng
  • Yu, Qiang
Venue
Nature Communications
Published
2022-07-15
Volume
13
Issue
1
Pages
4118-4118
ISSN
2041-1723 (ISSN-L)
OpenAlex
W4285493755
Cited by
200
References
62
Citations by year
2026: 56 · 2025: 64 · 2024: 43 · 2023: 32 · 2022: 5
FWCI
15.07
Type
journal article
Language
en
Open access
Locations
  • Nature Communications (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • RePEc: Research Papers in Economics (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • University of Southern Denmark Research Portal (University of Southern Denmark) (submittedVersion, cc-by)
Funders
  • National Research Foundation
  • Agency for Science, Technology and Research (202D800029)
  • National Research Foundation Singapore (NRF-NRFF2017-03)
  • Medical Research Council
  • National Medical Research Council (OFIRG20nov-0085)
Topics
  • Health Sciences › Medicine › Oncology › Cancer Immunotherapy and Biomarkers
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cancer Research › Cancer, Hypoxia, and Metabolism
  • Life Sciences › Immunology and Microbiology › Immunology › Immune cells in cancer
Keywords
triple-negative breast cancer, tumor hypoxia, HIF-1α, HDAC1, polycomb repressive complex 2, epigenetic suppression, T cell exhaustion, natural killer cells, anti-PD-1 resistance, immunotherapy resistance, tumor microenvironment, immune evasion
MeSH terms
Animals, Hypoxia, Humans, Immunotherapy, Epigenesis, Genetic, Cell Line, Tumor, Mice, Tumor Microenvironment, Triple Negative Breast Neoplasms

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