TGF-β and VEGF cooperatively control the immunotolerant tumor environment and the efficacy of cancer immunotherapies
Tristan Courau, Djamel Nehar-Belaid, Laura Florez, Béatrice Levacher, Thomas Vazquez, Faustine Brimaud, Bertrand Bellier, David Klatzmann
Tristan Courau, Djamel Nehar-Belaid, Laura Florez, Béatrice Levacher, Thomas Vazquez, Faustine Brimaud, Bertrand Bellier, David Klatzmann
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Research Article Immunology Oncology

TGF-β and VEGF cooperatively control the immunotolerant tumor environment and the efficacy of cancer immunotherapies

Abstract

Tregs imprint an early immunotolerant tumor environment that prevents effective antitumor immune responses. Using transcriptomics of tumor tissues, we identified early upregulation of VEGF and TGF-β pathways compatible with tolerance imprinting. Silencing of VEGF or TGF-β in tumor cells induced early and pleiotropic modulation of immune-related transcriptome signatures in tumor tissues. These were surprisingly similar for both silenced tumors and related to common downstream effects on Tregs. Silencing of VEGF or TGF-β resulted in dramatically delayed tumor growth, associated with decreased Tregs and myeloid-derived suppressor cells and increased effector T cell activation in tumor infiltrates. Strikingly, co-silencing of TGF-β and VEGF led to a substantial spontaneous tumor eradication rate and the combination of their respective inhibitory drugs was synergistic. VEGF and/or TGF-β silencing also restored tumor sensitivity to tumor-specific cell therapies and markedly improved the efficacy of anti–PD-1/anti–CTLA-4 treatment. Thus, TGF-β and VEGF cooperatively control the tolerant environment of tumors and are targets for improved cancer immunotherapies.

Authors

Tristan Courau, Djamel Nehar-Belaid, Laura Florez, Béatrice Levacher, Thomas Vazquez, Faustine Brimaud, Bertrand Bellier, David Klatzmann

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Figure 4

VEGF or TGF-β silencing abolishes Treg and activated/memory Treg (amTreg) accumulation and proliferation in the tumor-draining lymph nodes, but only TGF-β silencing affects tumor-infiltrating Tregs.

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VEGF or TGF-β silencing abolishes Treg and activated/memory Treg (amTreg...
(A) Percentages of Tregs among CD4+ T cells (upper panels) and CD44hi amTregs (lower panels) in draining lymph nodes (dLNs, left panels) and nondraining lymph nodes (ndLNs, right panels) of tumor-bearing mice, analyzed at the indicated time points after s.c. inoculation of 105 WT or silenced B16 tumor cells; n = 12 mice per group in 3 independent experiments. (B) One-day tumor-bearing WT Thy1.2 mice received CFSE-labeled Thy1.1 congenic cells from naive C57BL/6 mice. Division profiles of Thy1.1+ donor Tregs and amTregs were evaluated by flow cytometry 10 days later. Mean percentages of cells that had undergone at least one division are shown in histograms; n = 3 mice per group. (C) Kinetic representation of Treg proportions in WT, VEGF- or TGF-β–silenced tumors after s.c. inoculation in WT mice; n = 8 mice per group in 2 independent experiments. (D and E) Flow cytometric quantification of (D) Ki67 and (E) annexin V expression in CD4+Foxp3+ Tregs in WT, VEGF–, or TGF-β–silenced tumors at day 20; n = 4–7 mice per group in 2 independent experiments. (F–H) Kaplan-Meier survival curves of C57BL/6 WT mice depleted or not of Tregs by anti-CD25 antibody (PC61) and challenged the day after with 105 WT (F), VEGF- (G), or TGF-β– (H) silenced tumor cells; n = 10 mice per group in 2 independent experiments. Statistical significance of the survival curves was analyzed by using the log-rank test, and the other results by using the Ordinary one-way ANOVA test with Bonferroni’s correction (*P < 0.05; **P < 0.005, ***P < 0.001).