Sci Signal
-
Clinical Trial
Exosomes from bone marrow mesenchymal stem cells contain a microRNA that promotes dormancy in metastatic breast cancer cells.
Breast cancer patients often develop metastatic disease years after resection of the primary tumor. The patients are asymptomatic because the disseminated cells appear to become dormant and are undetectable. Because the proliferation of these cells is slowed, dormant cells are often unresponsive to traditional chemotherapies that exploit the rapid cell cycling of most cancer cells. ⋯ Among various microRNAs (miRNAs) increased in BM-MSC-derived exosomes compared with those from adult fibroblasts, overexpression of miR-23b in BM2 cells induced dormant phenotypes through the suppression of a target gene, MARCKS, which encodes a protein that promotes cell cycling and motility. Metastatic breast cancer cells in patient bone marrow had increased miR-23b and decreased MARCKS expression. Together, these findings suggest that exosomal transfer of miRNAs from the bone marrow may promote breast cancer cell dormancy in a metastatic niche.