Instant fluorescence lifetime imaging microscopy reveals mechano-metabolic reprogramming of stromal cells in breast peritumor microenvironment

The breast peritumor microenvironment (pTME) is increasingly recognized as a mediator of breast cancer progression and treatment resistance. However, how tumor compressive forces (i.e., solid stresses) influence it remains unclear. Using instant fluorescence lifetime imaging microscopy (FLIM), we show that in vitro compression metabolically reprograms stromal cells found in the breast pTME. Namely, compression shifts fibroblasts and differentiated adipocytes toward a more glycolytic state, but promotes increased oxidative phosphorylation in undifferentiated adipocytes. Through RNA-sequencing, we confirmed that compression downregulates oxidative phosphorylation and upregulates glycolysis in fibroblasts. Furthermore, we demonstrate that compression induces mitochondrial dysregulation in undifferentiated adipocytes, driven partly by upregulated mitophagy and disrupted fission/fusion dynamics. The analysis of human breast cancer samples confirms these stromal cell types recapitulate these distinct metabolic states, consistent with in vitro findings. By elucidating tumor-host mechano-metabolic interactions, these results will inform the development of innovative treatment strategies to improve survival.