1. Epigenetic silencing of miR-200c in breast cancer is associated with aggressiveness and is modulated by ZEB1
- Author
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Alessandra di Gennaro, Silvia Borgna, Manuela Santarosa, Roberta Maestro, Valentina Damiano, Michela Guardascione, Giulia Brisotto, Tiziana Perin, and Michela Armellin
- Subjects
0301 basic medicine ,Cancer Research ,Methylation ,Biology ,Chromatin remodeling ,Demethylating agent ,Chromatin ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,0302 clinical medicine ,Histone ,chemistry ,030220 oncology & carcinogenesis ,microRNA ,DNA methylation ,Genetics ,Cancer research ,biology.protein ,Gene silencing - Abstract
Loss of expression of miR-200 family members has been implicated in cellular plasticity, a phenomenon that accounts for epithelial-to-mesenchymal transition (EMT) and stem-like features of many carcinomas and is considered a major cause of tumor aggressiveness and drug resistance. Nevertheless, the mechanisms of miR-200 downregulation in breast cancer are still largely unknown. Here we show that miR-200c expression inversely correlates with miR-200c/miR-141 locus methylation in triple-negative breast tumors (TNBC). Importantly, low levels of miR-200c expression and high levels of miR-200c/miR-141 locus methylation associated with lymph node metastasis. Moreover, miR-200c/miR-141 locus methylation was significantly related to high expression of ZEB1 in two independent TNBC series. Silencing of ZEB1 in vitro reduced miR-200c/miR-141 DNA methylation and, concurrently, decreased histone H3K9 trimethylation. This chromatin modifications were paralleled by an increase in the expression of both miR-200c and E-cadherin. Similar effects were achieved by treatment with a demethylating agent. Our data suggest that gene methylation is an important element in the regulation of the miR-200c/ZEB1 axis and that chromatin remodeling of the miR-200c/miR-141 locus is affected by ZEB1 and, thus, contributes to ZEB1-induced cellular plasticity. © 2016 Wiley Periodicals, Inc.
- Published
- 2016