Abstract PO4-28-02: Adipocyte Progenitor-Mediated Effects on Mammary Cancer Cells

Abstract Treatment challenges in breast cancer arise from significant heterogeneity found within breast tumors and the surrounding microenvironment. The tumor microenvironment presents a complex ecosystem which comprises diverse stromal cells including immune, endothelial and fibroblast cell lineages and the extracellular matrix that support tumor progression. Adipocytes represent an abundant cell population in the normal breast and prior studies have reported a crosstalk between adipocytes and mammary cancer cells. De-differentiation of adipocytes into adipocyte progenitor-like cells is linked to a pro-tumorigenic microenvironment in mouse mammary tumors. We have previously demonstrated that adipocyte progenitors in the murine mammary stroma have the capacity to generate epithelial lineages during mammary epithelial growth. The influence of adipocyte progenitors in the mammary tumor microenvironment is not known. In this study, we investigated the effects of adipocyte progenitors on mammary cancer cells and their interactions using the 3T3-L1 adipocyte precursor (AP) cell line and the EO771 syngeneic mammary cancer (MCa) cell line. AP and MCa cell lines were co-cultured, after which MCa cell growth, invasion and migration were assessed using established in vitro assays. MCa cells cultured alone were also exposed to AP-conditioned media to determine whether secreted factors derived from APs could modulate MCa cells. AP cells were found to alter the behavior of MCa cells, affecting their cell proliferation, migration, and cellular phenotype. This work infers the potential of adipocyte progenitors to regulate mammary cancer growth and progression, which warrants further investigation into their fate and role in vivo during mammary tumorigenesis. Keywords: breast cancer, adipocyte progenitors, tumor microenvironment Citation Format: Jacqulene Sunder Singh, Purna Joshi, Emma Unger. Adipocyte Progenitor-Mediated Effects on Mammary Cancer Cells abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-28-02.