Fig. 6: Pharmacological blockade of 6PGD reduces MDSC immunosuppression and enhances anti-PD-1 immune checkpoint blockade efficacy. | Nature Communications

Fig. 6: Pharmacological blockade of 6PGD reduces MDSC immunosuppression and enhances anti-PD-1 immune checkpoint blockade efficacy.

From: 6-Phosphogluconate dehydrogenase promotes mitochondrial fusion and immune suppression in tumor-associated monocytic suppressor cells

Fig. 6: Pharmacological blockade of 6PGD reduces MDSC immunosuppression and enhances anti-PD-1 immune checkpoint blockade efficacy.The alternative text for this image may have been generated using AI.

A For pharmacological inhibition of 6PGD, MDSCs were generated in vitro using IL-6 (40 ng/mL) and GM-CSF (40 ng/mL) for 4 days from the bone marrow (BM) of wild type (WT) mice in the presence of 6AN (5 µM) or vehicle (DMSO). 6AN at 5 µM did not induce significant toxicity on M-MDSCs as measured by Annexin V staining. n = 4 per group. Two-tailed t-test. B, C MDSCs were generated as in (A), and Arginase 1 and iNOS2 expression were examined in M-MDSC by flowcytometry (B). Immunosuppressive function of sorted M-MDSCs was determined by co-cultured with anti-CD3/anti-CD28 activated T cells (CFSE-labeled) at 1:8 (MDSC: T cell) ratio for 72 h. C Data are representative of three independent experiments. n = 3; One-way ANOVA. D To examine suppressive function of M-MDSCs generated as in (A), sorted M-MDSC (1 × 106 cells per mouse) were intravenously injected into subcutaneous (s.c.) AT3 mice tumor model (5 × 105 cells per mouse) on day 3 and day 6 post-tumor induction. Mice receiving only AT3 cells served as controls (Untreated). n = 6; Two-way ANOVA. E Tumor growth in Pgdfl/fl and Pgdfl/flLysMCre mice injected subcutaneously with AT3 breast cancer cells, followed by 200 μg anti-PD-1 monoclonal antibody or isotype control (2× weekly; intraperitoneally (i.p.)). n = 7 mice per group. Two-way ANOVA. F, G Tumor growth was measured in WT immunocompetent (F) or NSG immunodeficient (G) mice injected s.c. with AT3 breast cancer cells (5 × 105 cells per mouse) followed by 6AN (1 mg/kg) or vehicle (1% DMSO) i.p., every 3 days and 200 μg anti-PD-1 depleting antibody or isotype control (2× weekly, i.p.). n = 7; Two-way ANOVA. H, I Flowcytometry analysis of the frequency of tumor-infiltrating CD8+ T cells (H) and their TNF expression (I) at day 38 (endpoint) in the AT3 breast cancer model as in E.  n = 7; One-way ANOVA. J, K Flowcytometry analysis of the frequency of tumor-infiltrating CD8+ T cells (J) and their TNF expression (K) at day 32 (endpoint) experimental mice as in (F). n = 7; One-way ANOVA. All data are shown as mean ± SEM.

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