Single-cell analysis reveals the stromal dynamics and tumor-specific characteristics in the microenvironment of ovarian cancer

We characterized high-grade ovarian serous carcinoma TIME based on integrative single-cell transcriptomics analysis of public and in-house datasets. We identified a distinct transcriptomic landscape of both immune and non-immune cells between the dense and more sparse stromal tumors. High stromal tumors contain a lower fraction of infiltrating activated CXCR3+ GRZB+ IFN+ IL2R+ CD8+ T and NCR3+ KLRD1+ natural killer (NK) cells and CXCL1+ macrophages. Next, we determined the potential interplays between non-immune and immune cells. High stromal tumors showed increased expression of CXCL12 in epithelial cancer cells and CA-MSCs. Cell-cell communication analyses suggested that epithelial cancer cells and CA-MSCs secreted CXCL12 interacts with the CXCR4 receptor on NK and CD8+ T cells. Using CXCL12 and/or CXCR4 neutralizing antibodies, we confirmed the immunosuppressive role of the CXCL12-CXCR4 axis in CA-MSC-induced immune suppression. OVCA mRNA profiles of the following two groups: (1) high-stromal samples, and (2) low stromal samples.