HUMAN OSTEOSARCOMA CELL-LINES ARE DEPENDENT ON INSULIN-LIKE GROWTH-FACTOR-I FOR IN-VITRO GROWTH

Osteogenic sarcoma is the most common bone tumor of childhood and typi cally occurs during the adolescent growth spurt when growth hormone an d insulin-like growth factor I (IGF-I) may be at their lifetime highes t levels. Since IGF-I is involved in normal bone growth and differenti ation, we have evaluated the possible role of IGF-I signaling in the g rowth of human osteogenic sarcoma cell lines. In this study, we demons trate that in vitro survival of cells is dependent on exogenously supp lied IGF-I. Furthermore, we show that these cells display functional I GF-I receptors on their surface and that in vitro growth is inhibited by blocking these receptors either by monoclonal antibodies or by anti sense oligonucleotides. These data demonstrate that human osteogenic s arcoma cell lines are dependent on signaling through the IGF-I recepto r for in vitro survival and proliferation. Furthermore, they suggest t hat modulation of the growth hormone/IGF-I axis may affect the growth of these tumors in vivo.