Abstract 5727: Metabolic status and adaptability of breast cancer stem cells

Abstract

Abstract Breast cancer stem cells (BCSCs) represent the subpopulation of malignant cells that cause tumor initiation, metastasis, and recurrence. BCSCs resist therapy with radiation and standard drugs, emphasizing the need to identify new vulnerabilities as therapeutic targets. Here, we investigated the metabolism of BCSCs at single-cell resolution using molecular imaging and scRNA sequencing techniques. We imaged retention of the fluorescent dye PKH26 or expression of a CRISPR/Cas9-engineered ALDH1A3-mCherry promoter-reporter to identify BCSCs and metabolic state of cells by two-photon microscopy with fluorescence lifetime imaging (FLIM) of endogenous NADH. We previously reported that sorted BCSCs exhibited enhanced metabolic plasticity relative to bulk tumor cells in 2D culture and rapidly metabolically adapted to the glycolysis inhibitor 2-deoxyglucose (2DG). Since cells rewire signaling and metabolism in 3D environments, we utilized two-photon microscopy to quantify metabolism in secondary mammospheres and living animals. In both intact spheres and orthotopic tumor xenografts, BCSCs marked by either fluorescent reporter utilized glycolysis to a greater extent than bulk cancer cells. We validated our findings by correlating cellular entropy as a marker for cancer stem cells with metabolic pathway preferences on a single-cell basis. When treated with 2DG, mammospheres showed increased OXPHOS and a significant decrease in the percentage of ALDH1A3-mCherry+ cells. These data 1) highlight capabilities of FLIM to measure the metabolism of single cancer cells in physiologic environments; 2) correlate molecular phenotypes with real-time molecular imaging profiles of metabolism and stem-ness; and 3) reveal that BCSCs rely on glycolysis, suggesting a potential target for metabolic therapy. Citation Format: Johanna M. Buschhaus, Ayse J. Muniz, Ming Luo, Joseph P. Burnett, Nathan A. Truchan, Michael D. Brooks, Brock A. Humphries, Kathy E. Luker, Joerg Lahann, Duxin Sun, Max S. Wicha, Gary D. Luker. Metabolic status and adaptability of breast cancer stem cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5727.