Figure 7

Osteogenic BMPs promote cell proliferation in early progenitors and in OS cells. (a) C3H10T1/2 cells and human OS cells were infected with GFP or BMP9 adenovirus. At 24 h, 72 h, and 120 h post-infection, cells were collected, fixed, incubated with the propidium iodide (PI)/RNase staining buffer, and subjected to flow cytometry. Percentage of cells in S phase was statistically analyzed. Each assay condition was done in triplicate. (b) C3H10T1/2 cells and human OS cells were infected with AdBMP9 or AdGFP. At the indicated time points, cells were collected. Viable cells were counted. Each assay condition was done in triplicate. (c) Relationship between osteogenic differentiation and bone tumorigenesis. Osteogenic differentiation is a well-coordinated process including the repopulation of early progenitors and terminal differentiation of committed osteoblast cells (i). Any impairment in the early stages of osteogenic differentiation may prevent osteoprogenitor cells from undergoing terminal differentiation, hence leading to the development of bone tumors (ii). Reintroduction of Runx2 or treatment of differentiation agents (DA) may increase differentiation potential of OS cells and convert those cells into more differentiated osteoblasts or osteocytes. See text for detail.