title: Actions and interactions of glucocorticoids and transforming growth factor beta on two related human myeloma cell lines.
abstract: To evaluate possible involvement of a paracrine/autocrine inhibitory growth factor in myeloma cell growth, we studied the expression and actions of two forms of transforming growth factor beta (TGF-beta 1 and TGF-beta 2) on two closely related myeloma cell lines, OPM-1 and OPM-2. Earlier studies showed that both cell lines contain glucocorticoid receptors, but only OPM-2 cells are growth inhibited by dexamethasone (Dex). We found that OPM-2 growth was inhibited by TGF-beta, with TGF-beta 1 exerting a greater effect than TGF-beta 2, and Dex plus TGF-beta 1 acting synergistically. In OPM-1 (Dex insensitive), TGF-beta mRNA was not expressed, whereas it was induced by Dex in OPM-2. It was also possible to block partially the growth inhibition of Dex in OPM-2 cells by the addition of anti-TGF-beta 1 antibodies. These data suggest that the glucocorticoid effect(s) on myeloma cells may be mediated at least in part through modulation of internal and/or external levels of TGF-beta 1.
authors.affiliation: Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston 77550.
authors.forename: B H
authors.initials: BH
authors.lastname: Johnson
authors.forename: M
authors.initials: M
authors.lastname: Gomi
authors.forename: S B
authors.initials: SB
authors.lastname: Jakowlew
authors.forename: K
authors.initials: K
authors.lastname: Moriwaki
authors.forename: E B
authors.initials: EB
authors.lastname: Thompson
mesh_terms: D003907:Dexamethasone / Q000494:pharmacology*; D004347:Drug Interactions; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis; D012680:Sensitivity and Specificity; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D003907:Dexamethasone