title: A specific inhibitor of TGF-beta receptor kinase, SB-431542, as a potent antitumor agent for human cancers.
abstract: Small molecule inhibitors of signaling pathways have proven to be extremely useful for the development of therapeutic strategies for human cancers. Blocking the tumor-promoting effects of transforming growth factor-beta (TGF-beta) in advanced stage carcinogenesis provides a potentially interesting drug target for therapeutic intervention. Although very few TGF-beta receptor kinase inhibitors (TRKI) are now emerging in preclinical studies, nothing is known about how these inhibitors might regulate the tumor-suppressive or tumor-promoting effects of TGF-beta, or when these inhibitors might be useful for treatment during cancer progression. We have investigated the potential of TRKI in new therapeutic approaches in preclinical models. Here, we demonstrate that the TRKI, SB-431542, inhibits TGF-beta-induced transcription, gene expression, apoptosis, and growth suppression. We have observed that SB-431542 attenuates the tumor-promoting effects of TGF-beta, including TGF-beta-induced EMT, cell motility, migration and invasion, and vascular endothelial growth factor secretion in human cancer cell lines. Interestingly, SB-431542 induces anchorage independent growth of cells that are growth-inhibited by TGF-beta, whereas it reduces colony formation by cells that are growth-promoted by TGF-beta. However, SB-431542 has no effect on a cell line that failed to respond to TGF-beta. This represents a novel potential application of these inhibitors as therapeutic agents for human cancers with the goal of blocking tumor invasion, angiogenesis, and metastasis, when tumors are refractory to TGF-beta-induced tumor-suppressor functions but responsive to tumor-promoting effects of TGF-beta.
authors.affiliation: Department of Surgery and Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Halder
authors.forename: R Daniel
authors.initials: RD
authors.lastname: Beauchamp
authors.forename: Pran K
authors.initials: PK
authors.lastname: Datta
mesh_terms: D030201:Activin Receptors, Type I / Q000037:antagonists & inhibitors; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D001549:Benzamides / Q000494:pharmacology*; D015153:Blotting, Western; D002448:Cell Adhesion; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement; D004149:Dioxoles / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D008907:Mink; D008954:Models, Biological; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009389:Neovascularization, Pathologic; D017346:Protein Serine-Threonine Kinases; D051381:Rats; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors; D013997:Time Factors; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
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; D004149:Dioxoles; D004791:Enzyme Inhibitors; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; D017346:Protein Serine-Threonine Kinases; D030201:Activin Receptors, Type I; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625843:Tgfbr1 protein, rat