Exosomes, nano-sized cell-derived vesicles, have been employed as non-synthetic carriers of various pharmaceutics in numerous studies. As higher expression levels of miR-142-3p and miR-150 in breast cancer stem cells (BCSCs) are associated with their clonogenic and tumorigenic capabilities, the present study aims to exploit the mesenchymal stem cells-derived exosomes (MSCs-Exo) to deliver LNA-antimiR-142-3p into MCF7-derived cancer stem-like cells to suppress expression levels of miR-142-3p and miR-150 in order to reduce clonogenicity and tumorigenicity. Our results indicated that the MSCs-Exo can efficiently deliver the LNA-antimiR-142-3p to breast cancer stem-like cells to reduce the miR-142-3p and miR-150 expression levels. Furthermore, the inhibition of the oncomiRs with the delivery of LNA-antimiR-142-3p resulted in a significant reduction of clone-formation and tumor-initiating abilities of the MCF7-derived cancer stem-like cells. In conclusion, we showed that MSCs-derived exosomes could be used as a feasible nanovehicles to deliver RNA-based therapeutics into BCSCs to improve the cancer treatment. HIGHLIGHTS: Exosomes secreted by bone marrow-derived mesenchymal stem cells efficiently transfer the LNA-antimiR-142-3p to breast cancer stem cells. Exosomes-mediated delivery of LNA-antimiR-142-3p to the breast cancer stem cells leads to downregulation of miR-142-3p and miR-150 and the overexpression of target genes. Delivery of LNA-antimiR-142-3p by the exosomes reduces the colony formation capability of breast cancer stem cells in vitro. Inhibition of miR-142-3p and miR-150 by the LNA-antimiR-142-3p loaded exosomes reduces the tumorigenicity of breast cancer stem cells in vivo.
Keywords: APC; Breast cancer stem cells; Exosomes; LNA-antimir-142-3p; Mesenchymal stem cells; P2X7R.