Article Summary #9

Margottini, L. How Cancer Wreaks Havoc on Bone. ScienceNOW Daily News. 5 Feb 2010

A team of clinical pathologists found that an insulin-like hormone speeds the destruction of bone caused by malignant tumors. If this study is proven true, the results could point to drugs for slowing or stopping the damage to bones caused by cancer. The hormone relaxin has already been tied to cancer, and previous studies linked high levels of this hormone to aggressive endometrial and prostate cancer, as well as breast and thyroid. It still was unclear if relaxin was produced by cancerous tumors and could boost the destruction of bone tissue.

Relaxin belongs to the same class of hormones as the one produced in the testes, INSL 3. It was shown in previous studies that if its placed under a certain condition, INSL 3 interacts with osteoblasts that build up bone tissue. When the testes do not produce enough INSL 3, bone mass drops and osteoporosis occurs. Relaxin was found to trigger a similar effect, and researchers proved it by studying the effects of relaxin on cultured human bone cells. It was found that the hormone stimulates osteoclasts, which removes bone’s excess tissue. By binding with a receptor, relaxin caused the osteoclasts to consume too much bone tissue and release a huge quantity of calcium. Too much calcium into the blood causes hypercalcemia. It was also found by researchers that relaxin promotes growth, separation, and invasiveness of various tumors. Researchers added an anti-relaxin antibody to the cell cultures and resulted that the antibody prevented relaxin from binding with receptors and from causing bone damage. The findings suggest that a drug based on this antibody will inhibit the relaxin receptor and slow down bone damage.