MicroRNA Exert Macro Effects on Cancer Bone Metastasis

Bone metastasis is a deadly complication of cancers arising from many different primary tumor locations. Cross talk between cancer and bone cells is a well-established driver of bone metastasis, and recent work reveals microRNA (miRNA) as key players in this communication. Functional significance of miRNA was first demonstrated in cancer cells and has now also been documented in bone cell differentiation and skeletal remodeling. Review of recent literature highlights how different miRNAs can impact each step of the metastatic process by acting in both tumor and the metastatic niche to exert pleiotropic effects. Additionally, whether a miRNA is ultimately pro- or anti-metastatic dependents on the context—varied or even opposite outcomes can be conferred by the same miRNA in different cancer/cell types. In spite of this complexity, emerging research has provided a wealth of knowledge to uncover the exciting potential of miRNA as new diagnostic tools and therapeutic treatments for cancer bone metastasis.