Adipose MSC suppress breast cancer progression, metastasis and inhibit EMT pathways via exosomal-miRNAs following co-culture interaction

Introduction: Mesenchymal stem cells (MSCs) are commonly known to influence the progression of cancer due to their ability to migrate to the tumor microenvironment and interact with cancer cells. Exosomes have been found secreted by most cell types and have been shown to act as cargo carrying biomolecules including microRNA (miRNAs). Thus, understanding interaction between MSCs and cancer cells via exosomal miRNAs is crucial in determining the therapeutic role of MSC in treating breast cancer cells and relapse. Methods: Exosomes were harvested from the medium of indirect co-culture of MCF7-luminal and MDA-MB-231-basal breast cancer cells (BCCs) subtypes with adipose MSCs and profiled for miRNAs using next-generation sequencing. Results: The interaction resulted in the changes of exosomal miRNAs profiles that modulate essential signalling pathways and cell cycle arrest into dormancy via inhibition of epithelial-to-mesenchymal transition (EMT). The maintenance and induction of epithelial features in MCF7 and MDA cells have led to a positive correlation with the reduction of proliferation and metastasis as well as increased drug resistance. Overall, adipose MSCs mediated delivery of consensus miRNAs particularly miR-200 family in MCF7, miR-146a in MDA and miR-941 in both BCCs subtypes via exosomes. miRNA profiles of breast cancer cells subtypes co-cultured with adipose MSC were generated using next-generation sequencing.