MicroRNAs in the control of metastatic bone disease

•Metastatic bone disease occurs due to complex interactions between cancer cells and the bone microenvironment.•miRNAs important for bone homeostasis are often dysregulated in bone metastatic cancer cells.•Specific dysregulated miRNAs function to drive breast and prostate cancer metastasis to bone.•Functional activity of specific miRNAs promotes osteolytic and/or osteoblastic phenotypes.•miRNAs serve as potential therapeutic targets to prevent metastatic bone disease.

Bone metastasis is a common and devastating complication of late-stage breast and prostate cancer. Complex interactions between tumor cells, bone cells, and a milieu of components in their microenvironment contribute to the osteolytic, osteoblastic, or mixed lesions present in patients with metastasis to bone. In the past decade microRNAs (miRNAs) have emerged as key players in cancer progression, but the importance of miRNAs in regulating cancer metastasis to bone is only now being appreciated. We emphasize here important concepts of bone biology and miRNAs in the context of breast and prostate cancer, and focus on recent advances that have improved our understanding of the role of specific miRNAs with direct involvement in metastatic bone disease.