Inhibition by two diphosphonates of bone lysis in tumor-conditioned media.

In order to test the effect of diphosphonates in inhibiting bone lysis induced by human tumors, neonatal mouse calvaria are cultured in sterile conditions in different media. Osteolysis is estimated by the amount of 45Ca released from bone to medium, the mice being given injections of 45Ca on their day of birth. An increased bone lysis is observed when calvaria are incubated in the same medium conditioned from cultured tumor fragments. This effect is significantly decreased when the mice have been treated with either ethanehydroxydiphosphonate or dichloromethylenediphosphonate. These experiments represent a first step in estimating the potential effects of different drugs on malignant osteolysis.