title: New bone resorption stimulation factor elaborated by a human osteosarcoma cell line.
abstract: The FM-2 cell line is a cloned, immortalized cell line derived from a human osteosarcoma. Conditioned medium from FM-2 cultures contains a factor which stimulates calcium mobilization from fetal rat bone organ cultures. Treated bones contain increased numbers of osteoclasts and decreased bone matrix. This factor has a molecular weight of approximately 29,000 as determined by gel filtration. Its biological activity is dependent on a protein moiety and is completely inhibited by calcitonin. Its synthesis by the FM-2 line is dependent on cell density and replenishment of fresh medium. This factor is not parathyroid hormone, a vitamin D metabolite, prostaglandin E, epidermal growth factor, or osteoclast-activating factor, all of which have bone-resorbing activities. Also, FM-2-conditioned medium inhibits collagen synthesis in fetal rat calvaria cells and decreases alkaline phosphatase levels in an osteoblastic cell line, and these two properties coelute with the calcium-mobilizing factor from a hydroxylapatite column. These biological products, synthesized by a cell line derived from a tumor, may represent physiological factors normally synthesized by a subpopulation of bone cells.
mesh_terms: D000818:Animals; D001681:Biological Assay; D001688:Biological Products / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D002999:Clone Cells; D016207:Cytokines; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005260:Female; D005333:Fetus; D006801:Humans; D051379:Mice; D012516:Osteosarcoma / Q000378:metabolism*; D011247:Pregnancy
chemical_list: D001688:Biological Products; D016207:Cytokines; C025940:bone resorption factor; D004815:Epidermal Growth Factor; D002118:Calcium