Effects of combining transforming growth factor beta and 1,25-dihydroxyvitamin D3 on differentiation of a human osteosarcoma (MG-63).

摘要: Transforming growth factor beta (TGF beta) and 1,25-dihydroxyvitamin D3 (1,25D3), when added simultaneously to a human osteosarcoma cell line, MG-63, induce alkaline phosphatase activity 40-70-fold over basal levels, 6-7-fold 1,25D3 treatment alone, 15-20-fold TGF alone. synergistically increased specific in both matrix vesicles plasma membrane isolated from the cultures, but was greater targeted vesicle fraction. Inhibitor cleavage studies proved that enzymatic liver/bone/kidney phosphatase. Preincubation of MG-63 cells with for 30 min before addition sufficient maximal induction enzyme activity. Messenger RNA 2.1-fold beta, 1.7-fold 1,25D3, 4.8-fold combination at 72 h. Human protein as detected by radioimmunoassay stimulated only 6.3-fold control levels combination. This factors tested their effect on production three other osteoblast proteins: collagen type I, osteocalcin, fibronectin. inhibited 1,25D3-induced osteocalcin production, whereas were additive fibronectin I production. appears modulate differentiation effects this osteoblast-like thereby retain non-fully differentiated state.