Obesity, Metabolism and Breast Cancer Metastasis

Obesity, metabolic reprogramming, and breast cancer metastasis: Role of extracellular vesicles Abstract Obesity increases the risk of triple-negative breast cancer(TNBC) and its progression to metastasis.

Considering that only ~ 27% of the subjects survive past 5-years when the disease has metastasized, it is critical to understand howobesity-associated changes in body composition and metabolic homeostasis are transducedby the cancer cells and distant organs.

In obesity, the hypertrophic and metabolically reprogrammed adipose tissue secretes high amounts of extracellular vesicles (EVs).

In cancer biology, EVs are gaining increasing interest due to their ability to impact the recipient cells' cellular programming by delivering functional molecules, including nucleic acids, proteins, lipids, and metabolites.

The internalization of EVs' cargo contributes to the epithelial-to- mesenchymal (EMT) transformation of the recipient cell and the metastatic niche formation.

To mitigate metastatic potential induced by obesity and increase therapeutic response in obese women, it is crucial to understand the effects of EVs-derived from the obese tumor microenvironment (TME) and their contribution to metabolic reprogramming and metastatic progression, locally and in distant organs.

In this proposal, we hypothesize that EVs derived from obese versus normoweight mice regulate PC activity promoting metabolic reprogramming and metastasis.

To test this hypothesis, we will use a mouse model of obesity and TNBC to determine the impact of EVs isolated from a mouse model of obesity and TNBC on PC activity, tumor metabolism, and activation of EMT. EVs will be isolated from serum, tumor, and adipose tissue. The PC content of EVs will be screened by targeted proteomics and RNAseq.

Tumor cells, MetMwntlung and 4T1, and normal fibroblasts will be cultured and exposed to isolated EVs. The impact of EVs treatment on the expression of PC and EMT mediators will be measured by qPCR.

The metabolic substrate dependency will be determined by isotope labeling analysis using GC-MS, and mitochondrial function will be determined by Seahorse metabolic flux analysis and respirometry.

The epithelial/mesenchymal phenotype will be evaluated by immunohistochemistry and immunofluorescence using a panel of monoclonal antibodies against established EMT-related proteins. This research will elucidate the role of EVs in the crosstalk between obesity, cancer metabolism, and TNBC metastasis.

The results from these studies will lead to the identification of mechanistic targets and intervention strategies to reduce the burden of obesity in women with TNBC.