Co-targeting TGF-β and PD-L1 sensitizes triple-negative breast cancer to experimental immunogenic cisplatin-eribulin chemotherapy doublet
Laura Kalfeist, Fanny Ledys, Stacy Petit, Cyriane Poirrier, Samia Kada Mohammed, Loïck Galland, Valentin Derangère, Alis Ilie, David Rageot, Romain Aucagne, Pierre-Simon Bellaye, Caroline Truntzer, Marion Thibaudin, Mickaël Rialland, François Ghiringhelli, Emeric Limagne, Sylvain Ladoire
Laura Kalfeist, Fanny Ledys, Stacy Petit, Cyriane Poirrier, Samia Kada Mohammed, Loïck Galland, Valentin Derangère, Alis Ilie, David Rageot, Romain Aucagne, Pierre-Simon Bellaye, Caroline Truntzer, Marion Thibaudin, Mickaël Rialland, François Ghiringhelli, Emeric Limagne, Sylvain Ladoire
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Research Article Immunology Oncology

Co-targeting TGF-β and PD-L1 sensitizes triple-negative breast cancer to experimental immunogenic cisplatin-eribulin chemotherapy doublet

Abstract

In preclinical mouse models of triple-negative breast cancer (TNBC), we show that a combination of chemotherapy with cisplatin (CDDP) and eribulin (Eri) was additive from an immunological point of view and was accompanied by the induction of an intratumoral immune and inflammatory response favored by the immunogenic cell death induced by CDDP, as well as by the vascular and tumor stromal remodeling induced by each chemotherapy. Unexpectedly, despite the favorable immune context created by this immunomodulatory chemotherapy combination, our models remained refractory to the addition of anti–PD-L1 immunotherapy. These surprising observations led us to discover that CDDP chemotherapy was simultaneously responsible for the production of TGF-β by several populations of cells present in tumors, which favored the emergence of different subpopulations of immune cells and cancer-associated fibroblasts characterized by immunosuppressive properties. Accordingly, co-treatment with anti–TGF-β restored the immunological synergy between this immunogenic doublet of chemotherapy and anti–PD-L1 in a CD8-dependent manner. Translational studies revealed the unfavorable prognostic effect of the TGF-β pathway on the immune response in human TNBC, as well as the ability of CDDP to induce this cytokine also in human TNBC cell lines, thus highlighting the clinical relevance of targeting TGF-β in the context of human TNBC treated with chemoimmunotherapy.

Authors

Laura Kalfeist, Fanny Ledys, Stacy Petit, Cyriane Poirrier, Samia Kada Mohammed, Loïck Galland, Valentin Derangère, Alis Ilie, David Rageot, Romain Aucagne, Pierre-Simon Bellaye, Caroline Truntzer, Marion Thibaudin, Mickaël Rialland, François Ghiringhelli, Emeric Limagne, Sylvain Ladoire

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Figure 2

The CDDP-Eri doublet induces ICD markers.

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The CDDP-Eri doublet induces ICD markers. (A) 4T1 cells were treated wit...
(A) 4T1 cells were treated with Eri (50 nM), CDDP (4 μM), DXR (500 nM), or CDDP-Eri. Drug concentrations correspond to the IC50 at 48 hours. ICD markers were analyzed at 24 hours and 48 hours. Heatmap shows normalized marker expression and statistical significance. (B) Pie charts indicate the proportion of ICD marker positivity across independent experiments (1-way ANOVA). (C) EIF2α phosphorylation (Ser51) and LC3I/II levels were assessed by Western blotting. Heatmaps represent the densitometric phosphorylated/total ratio (1 representative experiment of 2). (D and E) Experimental design. 4T1 tumor–bearing mice received CDDP, Eri, or both. Four days later, tumor cells were isolated for NanoString analysis. Heatmap in D shows normalized gene expression; volcano plot in E indicates statistical significance (n = 4/group); 1-way ANOVA. (F) CD31+ endothelial cell proportions were measured by flow cytometry on post-treatment days 4, 8, and 14. Dot plots show CD31+ populations at day 8 (n ≥ 6/group). (G) CD31+ cells were quantified by IHC using QPath (scale bar: 200 μm). (H) CAF proportions were assessed according to PDPN expression using flow cytometry on day 8. Dot plots represent PDPN+ cells (n ≥ 6/group). (I) Correlations between CD31+, CAF, and CTL proportions were analyzed (n ≥ 11). (J) CTL proportions were evaluated on the basis of CAF and CD31+ levels (> median = high, < median = low). Box plots show the mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001, by 2-way ANOVA. Ctrl, control.