osteoclasts tagged posts

Comparing volume and activity of the cells that break down bone density in the upper and lower jaw bones of Medaka fish after 56 days spent aboard the International Space Station with those on the ground. Credit: Chatani et al, Sci. Rep. 5, 14172 (2015)

During spaceflight, astronauts lose bone mineral density, but it is not clear exactly what causes this loss. They reared small freshwater fish aboard the International Space Station for 56 days and examined the animals’ jawbones and teeth for any effects from microgravity. Previous studies suggest that microgravity activates osteoclasts, cells that control the breakdown of bone tissue, and the Medaka fish investigation examined the relationship between this increased osteoclast activity and reduced bone mineral density.

Investigators found ...

Migrating tumor cells produce a protein that aids them to set up home in bones, researchers show. If a tumor develops metastases, the chances of the patient’s survival will be severely diminished. Cancer cells that leave the primary tumor, travel through the body, and set up home in distal organs such as lungs and bones start to express cathepsin K ~ primarily found only in the bone and is secreted by osteoclasts.

Shastri and Christensen found in cell cultures, cathepsin K activated matrixmetalloprotease-9 (MMP-9), one of the key regulators of tumour development. MMP-9 can digest the bone matrix thereby allowing the arriving cancer cells to adapt and survive in their new environment...