miR-424/503 modulates Wnt/β-catenin signaling in the mammary epithelium by targeting LRP6.
EMBO Rep 2021;
22:e53201. [PMID:
34633138 PMCID:
PMC8647148 DOI:
10.15252/embr.202153201]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 09/03/2021] [Accepted: 09/10/2021] [Indexed: 11/09/2022] Open
Abstract
During the female lifetime, the expansion of the epithelium dictated by the ovarian cycles is supported by a transient increase in the mammary epithelial stem cell population (MaSCs). Notably, activation of Wnt/β-catenin signaling is an important trigger for MaSC expansion. Here, we report that the miR-424/503 cluster is a modulator of canonical Wnt signaling in the mammary epithelium. We show that mammary tumors of miR-424(322)/503-depleted mice exhibit activated Wnt/β-catenin signaling. Importantly, we show a strong association between miR-424/503 deletion and breast cancers with high levels of Wnt/β-catenin signaling. Moreover, miR-424/503 cluster is required for Wnt-mediated MaSC expansion induced by the ovarian cycles. Lastly, we show that miR-424/503 exerts its function by targeting two binding sites at the 3'UTR of the LRP6 co-receptor and reducing its expression. These results unveil an unknown link between the miR-424/503, regulation of Wnt signaling, MaSC fate, and tumorigenesis.
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