PO-268 Adipose-derived mesenchymal stem cells microenvironment promotes the tumorigenic phenotype in triple negative breast cancer cell line

Abstract

IntroductionBreast cancer is one of the common cause of cancer-related deaths in women, and the vast majority of breast cancer-related deaths involve metastatic disease. Thus, an understanding of the molecular and cellular mechanism supporting tumour progression is essential for developing targeted treatments. Recently, several studies have recognised the critical role of the metabolic setting and of microenvironmental cues in tumour development and therapeutic responses. In the present study we investigated the tumor-stroma metabolic interplay in MDA-MB-231 (high metastatic) cultured with conditioned medium (CM) from mammary adipose tissue-derived mesenchymal stem cells (MSC) either under high (HG) and low glucose (LG) regimen.Material and methodsMetabolic fluxes analyses were performed with Seahorse Bioanalyzer providing both mitochondrial respiratory activity, as oxygen consumption rate (OCR), and glycolysis-related extracellular acidification rate (ECAR). Live cell imaging for mitochondrial membrane potential Δψm, was performed by confocal microscopy by using TMRE as selective probe. Cell migration was evaluated by scratch assay monitoring the wound’s closure after 24 hour.Results and discussionsMetabolic fluxes analysis showed that HG growth condition caused a significant reduction of OCR and ECAR in MDA cell line as well as in MSC. MDA grown in MSC-derived CM revealed a dampening of OCR and ECAR and this effect was attained irrespectively of the glucose concentration. Analysis of Δψm showed a significant decrease only in MDA cultured with CM from HG-MSC. Intriguingly, in a specular setup MSC cultured with CM from theMDA, a significant reduction of ECAR, both in HG and LG was observed whereas OCR resulted to be strongly reduced only in HG. Our results would indicate a reciprocal interplay between the one of the most aggressive breast cancer cell line and MSC in rewiring the mitochondrial oxidative metabolism and likely the tumour phenotype. Consistently, in vitro scratch assay showed an increasing migration of MDA cultured with CM from MSC HG, thus suggesting a key role of MSC in facilitating cancer progression/invasiveness.ConclusionOur results strongly support the involvement of stromal MSC in tumour metabolism of malignant phenotypes. Further experiments are needed to define the factors released from MDA acting on MSC metabolism. Understanding these interactions is fundamental to develop therapeutic interventions addressing the MSC-tumour interaction.