Potent Role for MicroRNAs in Osteoporosis and Bone Metastases

Anthony L. Komaroff, MD

Overexpression of this small molecule also prevents bony metastases.

The balancing actions of osteoblasts and osteoclasts in bone metabolism are well known. But the signals that stimulate and repress activity in these cells are understood only poorly.

A team from the University of Texas reported that, in mice, a particular microRNA (miR), miR-34a, inhibits the action of osteoclasts and (to a lesser degree) stimulates the action of osteoblasts. Mice in which miR-34a is knocked out have markedly low bone mass. Conversely, mice engineered to overexpress miR-34a have the following characteristics:

They exhibit high bone mass.

They are less likely than control mice to develop osteoporosis after ovariectomy.

They experience fewer bony metastases after inoculation with a mouse melanoma cell line or a human breast cancer cell line.

In addition, a nanoparticle that mimics the action of miR-34a also attenuates both osteoporosis and bony metastases in mice.

CITATION(S):

Krzeszinski JY et al. miR-34a blocks osteoporosis and bone metastasis by inhibiting osteoclastogenesis and Tgif2. Nature 2014 Aug 28; 512:431.