Abstract
Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been reported to induce osteoblast differentiation in osteoblast precursor cells and to inhibit muscle differentiation in cells isolated from mice and rats. In the present study, I investigated the effects of rhBMP-2 on cell growth and differentiation of two kinds of human rhabdomyosarcoma cell lines, RD and SCMC-MM-1 (MM-1) . rhBMP-2 inhibited cell growth of RD cells, but had no such effect on MM-1 cells. rhBMP-2 inhibited formation of myosin-positive myotubes by RD cells, but had no apparent effect on changes in the number of desmin-positive MM-1 cells. Creatine phosphokinase activity in both RD cells and MM-1 cells was inhibited by rhBMP-2. rhBMP-2 stimulated both alkaline phosphatase activity and parathyroid hormone-dependent cAMP production in MM-1 cells, but had no such effect in RD cells. rhBMP-2 had no effect on osteocalcin production in either cell type. Transplantation of MM-1 cells with rhBMP-2 by means of diffusion chambers into the peritoneal cavity of athymic mice did not induce formation of cartilage or bone in the diffusion chambers, but did induce growth of ALP-positive cells. These results suggest that rhBMP-2 affects the growth and differentiation of human rhabdomyosarcoma cells.
