Expression of miR-200c in claudin-low breast cancer alters stem cell functionality, enhances chemosensitivity and reduces metastatic potential.
Oncogene 2015;
34:5997-6006. [PMID:
25746005 PMCID:
PMC4564359 DOI:
10.1038/onc.2015.48]
[Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 12/15/2014] [Accepted: 12/19/2014] [Indexed: 12/12/2022]
Abstract
Claudin-low tumors are a highly aggressive breast cancer subtype with no targeted treatments and a clinically documented resistance to chemotherapy. They are significantly enriched in cancer stem cells (CSCs), which makes claudin-low tumor models particularly attractive for studying CSC behavior and developing novel approaches to minimize CSC therapy resistance. One proposed mechanism by which CSCs arise is via an epithelial-mesenchymal transition (EMT), and reversal of this process may provide a potential therapeutic approach for increasing tumor chemosensitivity. Therefore, we investigated the role of known EMT regulators, miR-200 family of microRNAs in controlling the epithelial state, stem-like properties, and therapeutic response in an in vivo primary, syngeneic p53null claudin-low tumor model that is normally deficient in miR-200 expression. Using an inducible lentiviral approach, we expressed the miR-200c cluster in this model and found that it changed the epithelial state, and consequently, impeded CSC behavior in these mesenchymal tumors. Moreover, these state changes were accompanied by a decrease in proliferation and an increase in the differentiation status. miR-200c expression also forced a significant reorganization of tumor architecture, affecting important cellular processes involved in cell-cell contact, cell adhesion, and motility. Accordingly, induced miR200c expression significantly enhanced the chemosensitivity and decreased the metastatic potential of this p53null claudin-low tumor model. Collectively, our data suggest that miR-200c expression in claudin-low tumors offers a potential therapeutic application to disrupt the EMT program on multiple fronts in this mesenchymal tumor subtype, by altering tumor growth, chemosensitivity, and metastatic potential in vivo.
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