Figure 1.

The miRNA involvement in bone homeostasis and bone metastasis. (a) The miRNA-mediated regulation of osteoclast, osteoblast and chondrocyte differentiation and activity is essential for proper bone development and maintenance. Known positive (red) and negative (green) regulators are indicated. (b) Bone metastasis migration, invasion and homing to the bone microenvironment are controlled by multiple miRNAs. In addition, miRNAs regulate bone metastasis activity, including the tumor–stromal cross-talk that mediates osteolysis. Finally, the development of osteosarcoma depends on proper regulation of miRNAs that can enhance or inhibit tumor progression.