Ovarian Cancer Ascites Enriched for CCL23 Reduces Macrophage-Derived CXCL10 Secretion and Is Associated with Poor Patient Outcomes

Background: Ovarian cancer ascites contributes to the immunosuppressive tumor microenvironment (TME) via macrophage-derived chemokine ligand 23 (CCL23) signaling, T-cell exhaustion, and upregulating pro-inflammatory cytokines. However, the extent to which ascites-derived CCL23 concentrations associate with changes in pro- and anti-inflammatory cytokines and overall patient survival in ovarian cancer patients remains unknown. Methods: CCL23 concentrations and pro-inflammatory cytokines were measured from ascites of stage III and IV epithelial ovarian cancer patients by ELISA and Luminex assays, respectively. Kaplan–Meier survival analysis was performed using patient outcome data from Stanford University Hospital and the Cancer Genome Atlas. The impact of CCL23 peptides on pro-inflammatory cytokine secretion was evaluated in vitro using differentiated THP-1 monocytes. Results: A total of 40 patients were enrolled and CCL23 concentrations were detected in all ascites samples (median = 2.42 ng/mL; range [0.06–6.45]). Reduced survival time corresponded with high CCL23 containing samples (mOS: 3.2 years, [3.9 ng/mL]) versus intermediate (mOS: 6.0 years, [2.5 ng/mL]) or low (mOS: 5.9 years; [1.4 ng/mL]) groups. TGCA analysis of patient outcomes was confirmatory. A significant negative correlation was observed between high CCL23 ascites concentrations versus CXCL10 and soluble PD-1 cytokine levels. High tumor expression of CXCL10 was associated with improved survival (mOS; 5.9 years) versus low CXCL10 expression (mOS; 3.2 years). In vitro, CCL23-stimulated THP-1 macrophages exhibited reduced CXCL10 secretion via STAT-3 activation. Conclusions: High CCL23 concentrations in ovarian cancer ascites reduces CXCL10 secretion from myeloid cells and associates with reduced patient survival.