miR-218 directs a Wnt signaling circuit to promote differentiation of osteoblasts and osteomimicry of metastatic cancer cells

Academic Article


  • MicroRNAs (miRNAs) negatively and post-transcriptionally regulate expression of multiple target genes to support anabolic pathways for bone formation. Here, we show that miR-218 is induced during osteoblast differentiation and has potent osteogenic properties. miR-218 promotes commitment and differentiation of bone marrow stromal cells by activating a positive Wnt signaling loop. In a feed forward mechanism, miR-218 stimulates the Wnt pathway by downregulating three Wnt signaling inhibitors during the process of osteogenesis: Sclerostin (SOST), Dickkopf2 (DKK2), and secreted frizzled-related protein2 (SFRP2). In turn, miR-218 expression is up-regulated in response to stimulated Wnt signaling and functionally drives Wnt-related transcription and osteoblast differentiation, thereby creating a positive feedback loop. Furthermore, in metastatic breast cancer cells but not in normal mammary epithelial cells, miR-218 enhances Wnt activity and abnormal expression of osteoblastic genes (osteomimicry) that contribute to homing and growth of cells metastatic to bone. Thus, miR-218/Wnt signaling circuit amplifies both the osteoblast phenotype and osteomimicry-related tumor activity. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.
  • Authors

    Published In

    Digital Object Identifier (doi)

    Author List

  • Hassan MQ; Maeda Y; Taipaleenmaki H; Zhang W; Jafferji M; Gordon JAR; Li Z; Croce CM; Van Wijnen AJ; Stein JL
  • Start Page

  • 42084
  • End Page

  • 42092
  • Volume

  • 287
  • Issue

  • 50