Egfl6 promotes ovarian cancer progression by enhancing the immunosuppressive functions of tumor-associated myeloid cells
Sarah Hamze Sinno, … , Ronald J. Buckanovich, Sandra Cascio
Sarah Hamze Sinno, … , Ronald J. Buckanovich, Sandra Cascio
Published September 23, 2024
Citation Information: J Clin Invest. 2024;134(21):e175147. https://doi.org/10.1172/JCI175147.
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Research Article Immunology Oncology

Egfl6 promotes ovarian cancer progression by enhancing the immunosuppressive functions of tumor-associated myeloid cells

Abstract

Tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) play a critical role in resistance to immunotherapy. In this study, we identified epidermal growth factor-like 6 (Egfl6) as a regulator of myeloid cell functions. Our analyses indicated that Egfl6, via binding with β3 integrins and activation of p38 and SYK signaling, acts as a chemotactic factor for myeloid cell migration and promotes their differentiation toward an immunosuppressive state. In syngeneic mouse models of ovarian cancer (OvCa), tumor expression of Egfl6 increased the intratumoral accumulation of polymorphonuclear (PMN) MDSCs and TAMs and their expression of immunosuppressive factors, including CXCL2, IL-10, and PD-L1. Consistent with this, in an immune ‘hot’ tumor model, Egfl6 expression eliminated response to anti-PD-L1 therapy, while Egfl6 neutralizing antibody decreased the accumulation of tumor-infiltrating CD206+ TAMs and PMN-MDSCs and restored the efficacy of anti-PD-L1 therapy. Supporting a role in human tumors, in human OvCa tissue samples, areas of high EGFL6 expression colocalized with myeloid cell infiltration. scRNA-Seq analyses revealed a correlation between EGFL6 and immune cell expression of immunosuppressive factors. Our data provide mechanistic insights into the oncoimmunologic functions of EGFL6 in mediating tumor immune suppression and identified EGFL6 as a potential therapeutic target to enhance immunotherapy in patients with OvCa.

Authors

Sarah Hamze Sinno, Joshua A. Imperatore, Shoumei Bai, Noémie Gomes-Jourdan, Nyasha Mafarachisi, Claudia Coronnello, Linan Zhang, Eldin Jašarević, Hatice U. Osmanbeyoglu, Ronald J. Buckanovich, Sandra Cascio

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Figure 1

Egfl6 mice display an increased number of BM and splenic myeloid cells.

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Egfl6 mice display an increased number of BM and splenic myeloid cells....
(A and B) Graphs represent the percentage of B, CD4+, CD8+, and CD11b+ cells in BM (A) and spleen (B) of WT and Egfl6 mice. (C) Gating and quantification of Ly6G and Ly6C subsets of CD11b+ BM and splenic cells from healthy C57BL/6J (WT) and Egfl6 mice. (D) Volcano plot showing differentially expressed genes (DEGs) between BM CD11b+ cells of Egfl6 mice versus C57BL/6J (WT). P values determined via t test are plotted on the y axis. DEGs are colored in red. (E) Gating and quantification of BM-derived CD11b+Ly6G+Ly6C– cells stimulated with rGM-CSF ± rEgfl6. (F) qPCR analyses of indicated genes in sorted BM CD11b+ cells stimulated with rGM-CSF + rEgfl6. Stimulation with rGM-CSF alone was used as control. (G and H) ELISA of Granzyme B (GZMB) in IL-2 + CD3/CD28 activated CD8+ T cells and cultured directly with rEgfl6-stimulated BM-derived MDSC cells or MDSC control at different ratio (G) or with the conditioned media (CM) of rEgfl6-stimulated BM-derived MDSC cells or MDSC control (H). Unstimulated CD8+ T cells were used as negative control. Results were analyzed using unpaired 2-tailed t test or 2-way ANOVA. Experiments were performed in triplicate. Data are presented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.