title: SB-431542 and Gleevec inhibit transforming growth factor-beta-induced proliferation of human osteosarcoma cells.
abstract: Transforming growth factor-beta (TGF-beta) has growth-stimulating effects on mesenchymal cells and several tumor cell lines. The signaling pathway for this effect is, however, not well understood. We examined how TGF-beta stimulates proliferation of MG63 human osteosarcoma cells. Two distinct type I receptors for TGF-beta, ALK-1 and ALK-5, were expressed and functional in MG63 cells. Of these two receptors, ALK-5 appears to be responsible for the growth stimulation because expression of constitutively active ALK-5, but not ALK-1, stimulated proliferation of MG63 cells. SB-431542 (0.3 microM), a novel inhibitor of ALK4/5/7 kinase, suppressed TGF-beta-induced growth stimulation. DNA microarray analysis as well as quantitative real-time PCR analysis of RNAs from TGF-beta-treated cells demonstrated that several growth factors, including platelet-derived growth factor AA, were induced in response to TGF-beta in MG63 cells. Gleevec (1 microM) as well as AG1296 (5 microM) inhibited TGF-beta-induced growth stimulation of MG63 cells, suggesting that platelet-derived growth factor AA was mainly responsible for the growth-stimulatory effect of TGF-beta. We also examined the mechanisms of perturbation of growth-suppressing signaling in MG63 cells. We found that expression of c-Myc, which is down-regulated by TGF-beta in many other cells, was up-regulated in MG63 cells, suggesting that up-regulation of c-Myc expression may be the mechanism canceling growth-suppressing signaling of TGF-beta in MG63 cells.
authors: Department of Molecular Pathology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors: Shigeo
authors: S
authors: Matsuyama
authors: Manabu
authors: M
authors: Iwadate
authors: Miki
authors: M
authors: Kondo
authors: Masao
authors: M
authors: Saitoh
authors: Aki
authors: A
authors: Hanyu
authors: Kiyoshi
authors: K
authors: Shimizu
authors: Hiroyuki
authors: H
authors: Aburatani
authors: Hiromu K
authors: HK
authors: Mishima
authors: Takeshi
authors: T
authors: Imamura
authors: Kohei
authors: K
authors: Miyazono
authors: Keiji
authors: K
authors: Miyazawa
mesh_terms: D030201:Activin Receptors, Type I / Q000096:biosynthesis / Q000502:physiology; D030301:Activin Receptors, Type II; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001549:Benzamides / Q000494:pharmacology*; D001859:Bone Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis / Q000235:genetics; D004149:Dioxoles / Q000494:pharmacology*; D004347:Drug Interactions; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D000068877:Imatinib Mesylate; D051379:Mice; D041681:NIH 3T3 Cells; D020411:Oligonucleotide Array Sequence Analysis; D012516:Osteosarcoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D010879:Piperazines / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis / Q000235:genetics; D011743:Pyrimidines / Q000494:pharmacology*; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000096:biosynthesis / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000494:pharmacology / Q000502:physiology; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D000970:Antineoplastic Agents; D001549:Benzamides; C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004149:Dioxoles; D010879:Piperazines; D016271:Proto-Oncogene Proteins c-myc; D011743:Pyrimidines; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D000068877:Imatinib Mesylate; D017346:Protein Serine-Threonine Kinases; C425364:ACVRL1 protein, human; D030201:Activin Receptors, Type I; D030301:Activin Receptors, Type II; C498931:Acvrl1 protein, mouse; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625841:TGFBR1 protein, human; C000625842:Tgfbr1 protein, mouse