Ablation of hematopoietic stem cell derived adipocytes reduces tumor burden in syngeneic mouse models of high-grade serous carcinoma

Hematopoietic stem cell-derived adipocytes (HSCDAs) are an adipose subtype derived from myeloid precursors that are distinct from conventional mesenchymal adipocytes (CMAs). We hypothesized that HSCDAs promote high grade serous carcinoma (HGSC), the most common form of ovarian cancer. Despite similar rates of differentiation, primary human HSCDAs from female donors showed marked transcriptional differences from CMAs, including downregulation of cell cycle and upregulation of lipid metabolic pathways. HSCDAs secreted greater amounts of inflammatory cytokines than CMAs. We also conducted two independent tumor studies using ID8 and SO syngeneic HGSC murine models in immunocompetent mice that were either HSCDA Proficient (HSCDA-Pro; can make both adipocyte subtypes) or Deficient (HSCDA-Def; can only make CMAs). Tumor burden trended lower in HSCDA-Def mice in both models. Relative to HSCDA-Pro mice, omental ID8 tumors from HSCDA-Def mice downregulated transcription of multiple metabolic pathways that were enriched in human HSCDA cells in vitro, suggesting that ablation of HSCDAs altered the tumor metabolic environment. Compared to HSCDA-Pro mice, tumors from HSCDA-Def mice had lower densities of dendritic cells (DC) and natural killer (NK) cells, as well as fewer DCs, NKs, and B-cells in proximity to tumor cells. Our data suggest that HSCDAs alter the peritoneal immune and metabolic environment to support HGSC progression. ONE SENTENCE SUMMARYHematopoietic stem cell derived adipocytes may alter the peritoneal metabolic and immune environment to establish a metastatic niche and support ovarian cancer progression.