Macrophage-derived CCL23 upregulates expression of T-cell exhaustion markers in ovarian cancer
Menée à partir d'échantillons d'ascites et d'échantillons plasmatiques provenant de patientes atteintes d'un cancer séreux ovarien de haut grade et menée à partir de données du projet "The Cancer Genome Atlas", cette étude met en évidence un mécanisme par lequel le ligand CCL23, en induisant l'expression de points de contrôle immunitaires sur les lymphocytes T CD8+, favorise l'épuisement lymphocytaire et l'immunosuppression du microenvironnement tumoral
Background : Macrophages are an important component of the tumour immune microenvironment (TME) and can promote tumour growth and metastasis. Macrophage-secreted chemokine-ligand-23 (CCL23) induces ovarian cancer cell migration via chemokine-receptor 1 (CCR1). However, the effect of CCL23 on other immune cells in the TME is unknown. Methods : CCL23 levels were measured by ELISA. The expression of surface markers in exhaustion assays was quantified by flow cytometry. Signalling pathways were identified by phosphokinase array and validated by western blot. Results : Ascites from patients with high-grade serous ovarian cancer (HGSC) contain high levels of CCL23. Similarly, significantly higher CCL23 levels were found in plasma from HGSC patients compared to healthy individuals. RNA-seq analysis of ovarian cancer tissues from TCGA showed that expression of CCL23 correlated with the presence of macrophages. In tissues with high levels of CCL23 and macrophage content, the fraction of CD8 + T cells expressing exhaustion markers CTLA-4 and PD-1 were significantly higher compared to low-level CCL23 tissues. In vitro, CCL23 induced upregulation of immune checkpoint proteins on CD8 + T cells, including CTLA-4, TIGIT, TIM-3 and LAG-3 via phosphorylation of GSK3
β in CD8
+ T cells. Conclusions : Our data suggest that CCL23 produced by macrophages contributes to the immune-suppressive TME in ovarian cancer by inducing an exhausted T-cell phenotype.