Abstract

Matrix stiffness and glucose availability as determinants of metabolic reprogramming in mammary stromal cells. Martínez J., Ponce I. and Tobar N. Cell Biology Lab. INTA University of Chile. (jmartine@inta.uchile.cl). Introduction. Breast tumors belong to a type of desmoplastic lesion in which stiffer tissue structure is determinant in breast cancer progression. We have previously demonstrated that mammary fibroblasts, the main component of fibrotic stroma, are able to modify the tumor metabolic response (reprogramming) behaving as lactate producers, a property modulated by the availability of glucose. In the present work we propose that a stiffer extracellular matrix constitutes a signal for the onset of metabolic reprogramming. Material and Methods. RMF-621 mammary stromal cells were plated on artificial matrices (from a commercial source) with established stiffness for qPCR and western blot analysis of glucose and lactate transporters. Kinetic studies to analyze glucose and lactate transport were studied using Laconic, and FLIIPglu600606 FRET based lactate and glucose biosensors respectively using an individual cell in vivo assay. Lactate production was evaluated by gas chromatography coupled to mass spectrometry (GC-MS). Results. The results obtained can be summarized as follows: (i) lactate production by mammary stromal cells is proportional to the stiffness of the matrices. (ii) Glucose uptake by cells on stiffer surfaces is higher than their counterparts in soft matrices. (iii) Expression of tricarboxylic transporters follows the same tendency in favor of rigid matrices. Funding: FONDECYT 1181168