Sex steroids and bone metabolism: Comparison of in vitro effects of 17 beta-estradiol and testosterone on human osteosarcoma cell lines of various gender and differentiation

Although numerous clinical studies have demonstrated the beneficial effect of preventing postmenopausal bone loss in elder women by long-term estrogen administration, effects of estrogen at the cellular level still remain unc lear. Efforts to determine the precise role of bone cells in estrogen-media ted pathways are often hampered by the lack of suitable cell culture models . Presuming that sex steroids have a direct, stimulating effect on bone cel ls in vitro, we investigated the influence of 17 beta-estradiol, testostero ne and 1.25(OH)(2)D-3 on cell proliferation and differentiation using four established human osteosarcoma (HOS) cell lines of different gender of the donors (male origin: MG 63, HOS 58; female origin: SaOS 2, TE 85). These ce ll Lines are believed to represent different stages of osteogenic maturatio n. Thus, the aim of this study was to clarify if possible responses to sex steroids are related to gender or osteogenic commitment of the individual c ell culture. HOS cells were cultured in six-well plates and underwent hormo ne treatment (1 nM and 10 nM 17 beta-estradiol, 0.1 nM and 1 nhl testostero ne and 1 mu M 1,25(OH)(2)D-3) for 48 h hours. Cell proliferation was determ ined by measuring total cell numbers. Cell function was studied by measurin g alkaline phosphatase activity and secreted osteocalcin. Ln this study, es trogen significantly increased proliferation of both one male (MG 63) and o ne female (SaOSZ) cell line, but decreased proliferation of the female HOS TE 85 cell line significantly. Testosterone treatment had a positive effect on proliferation of only one female cell line (SaOS 2). A significant incr ease of alkaline phosphatase activity in SaOS ? and HOS 58 cells and of ost eocalcin levels in SaOS 2 cells was detected following estrogen treatment. Administration of 1,25(OH)(2)D-3 was followed by an increased cell prolifer ation in HOS 58, MG 63 and SaOS 2. Significant gender-related differences c ould not be demonstrated. In conclusion, response to hormonal treatment wit h sex steroids is not related to the gender of the osteosarcoma cell line, but rather depends on its osteoblastic commitment.