Abstract PO4-28-11: Murine Breast Cancer Cell Culture Supernatant Induces CAF-like and TAM-like Traits in Normal Cells

Abstract Several studies in the past have demonstrated the role of cell-to-cell interaction (crosstalk) between tumor cells and normal (nontumorigenic) cells in cancer progression and metastasis. Within the tumor microenvironment (TME), these interactions have a potential to transform the phenotypes and the behaviors of normal cells. Application of the 2D in-vitro cultures has been limited due to its inability to replicate the complex in-vivo TME. Conditioned Medium (CM) obtained from cultured cancer cells contains secreted growth factors that potentially regulate the phenotype and the functionality of normal cells. In this study, a culture of normal murine fibroblast NIH3T3 and macrophage RAW 264.7 cells with conditioned medium (CM) obtained from malignant mammary epithelial 4T1 cells (4T1CM) resulted in an altered phenotype with increased cell viability. 4T1CM treated NIH3T3 and RAW 264.7, in comparison with the respective control cells, resulted in an upregulation of the genes including- α-smooth muscle actin (αSMA), IL-10, CD206, and vascular endothelial growth factor (VEGF). In addition, 4T1.CM treated NIH3T3 showed an EMT phenotype as indicated by the regulation of EMT markers such as, E-cadherin, β-catenin, N-cadherin, and Vimentin. Interestingly, an upregulation of cyclooxygenase-2 (COX-2) and programmed death-ligand 1 (PDL-1) was observed in 4T1CM treated RAW 264.7, a tendency towards exhibiting an inhibitory immune response. Intriguingly, NIH3T3 cells conditioned with 4T1CM demonstrated an upregulation of stemness markers including- sex determining region Y-box 2, and Aldehyde dehydrogenase. Collectively, our study suggested a role for 4T1CM in transforming the normal NIH3T3 and RAW 264.7 into cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs). RNAseq experiments are underway to map differentially expressed genes (DEGs) that potentially regulate the 4T1CM induced transformation of NIH3T3 and RAW 264.7 cells. Furthermore, invitro drug testing in 3D model of these transformed cells to target the pathway intermediates may provide novel therapeutic intervention strategies. Citation Format: Biplov Sapkota, Naveen Chintalaramulu, Abhishek Pandit, Shilpa Thota, Rizwana Begum, Joseph Francis. Murine Breast Cancer Cell Culture Supernatant Induces CAF-like and TAM-like Traits in Normal 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 PO4-28-11.