Abstract 5567: Breast cancer cell alteration of immune cell transcriptome through indirect communication

Abstract

Abstract Crosstalk between tumor and non-tumor cells plays an important role in cancer progression and metastasis often leading to a modification of non-malignant cells into pro-oncogenic phenotypes. Understanding this process is important for diagnostic and therapeutic advances. We previously reported clinical validation results for a new way to detect early-stage breast cancer using a panel of RNA biomarkers from whole blood and a machine learning software-powered testing system. Recently, we showed that immune cells undergo transcriptomic and functional changes upon direct contact with breast cancer cells. Here, we report results from investigation of indirect communication between breast cancer and immune cells leading to cancer-driven immune cell transformation and activation of multiple oncogenic pathways. To characterize these modifications, we performed RNAseq and pathway analysis on a human monocytic cell line, THP1, exposed to media from triple negative breast cancer (TNBC) cells (MDA-MB-231) in culture. Our results demonstrate that 24 hours of THP1 cell exposure to soluble factors secreted by tumor cells leads to significant gene modulation, with over 1,100 differentially expressed genes (|Fold Change|>2; p<0.05). KEGG and Reactome enrichment analysis revealed overlap of multiple pathways between THP1 cells exposed to direct and indirect cancer cell contact conditions, such as cytokine-cytokine receptor interaction, JAK-STAT signaling pathways and others. TNF, NMP1, STING1 and TGM2 were identified as key upstream regulators potentially driving this transformation in both direct and indirect contact conditions. The S100 pathway, which we previously found to be activated by fluid shear stress in MDA-MB-231 cells was also activated in THP1 cells upon both direct and indirect contact. The observed gene expression changes in THP1 cells exposed to media from MDA-MB-231 suggests that indirect intercellular communication alone can transmit an oncogenic signal. These results support a role for secreted factors from breast cancer cells in transforming immune cells and modulating the gene expression markers detected by our blood test, expanding the potential for leveraging this type of tumor education response in advancing cancer detection and treatment. Citation Format: Jacob Kennard, Karen Norek, Kenneth Fuh, Robert D. Shepherd, Kristina D. Rinker, Olesya A. Kharenko. Breast cancer cell alteration of immune cell transcriptome through indirect communication [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5567.