Description
SB-431542 is a potent and selective inhibitor of the TGF-
β1 receptor ALK5 (IC
50 = 94 nM). It is a less potent antagonist of ALK4 (IC
50 = 140 nM) and ALK7. It does not affect the BMP receptors ALK2, ALK3, ALK6, or a panel of other kinases tested. SB-431542 specifically blocks Smad signaling, reducing gene expression relevant to fibrosis and cancer. Through its effects on ALK/Smad signaling, SB-431542 suppresses renewal in embryonic and induced pluripotent stem cells and promotes their differentiation.
Uses
SB 431542 is a known Src family kinase inhibitor that effectively blocks the transforming growth factor-β1-induced cell migration and invasion in both established and primary carcinoma cells. Potent TGF-beta inhibitor.
Definition
ChEBI: A member of the class of benzamides that is 4-(imidazol-2-yl)benzamide carrying additional 1,3-benzodioxol-5-yl and pyridin-2-yl substituents at positions 4 and 5 respectively on the imidazole ring.
General Description
A cell-permeable triarylimidazole compound that is shown to effectively inhibit cellular Smad2 phosphorylation (>90% inhibition by 10 μM inhibitor) upon vector-mediated expression of constitutively active ALK4, ALK5, or ALK7 in NIH 3T3 cells, while exhibiting little effect against Smad1 phosphorylation by other members of type I receptors for TGF-β in NIH 3T3 cultures expressing active ALK1, 2, 3, or 6. When tested directly in cell-free kinase assays, SB431542 is demonstrated to potently inhibit the activity of ALK4 and ALK5 (IC
50 = 140 nM and 94 nM, respectively) with no or much reduced potency toward a panel of 24 other kinases (IC
50 ≥10 μM in the presence of 10 μM ATP), including ALK2 and ALK6. Reported to improve the efficiency of 4-TF-induced human iPSCs generation from fibroblast cultures by >200-fold when used together with PD0325901 (Cat. No. 444966) and Thiazovivin (Cat. No. 420220).
Biological Activity
Potent and selective inhibitor of the transforming growth factor- β (TGF- β ) type I receptor activin receptor-like kinase ALK5 (IC 50 = 94 nM), and its relatives ALK4 and ALK7. Suppresses TGF- β -induced proliferation of human osteosarcoma cells. Stimulates proliferation, differentiation and sheet formation of ESC-derived endothelial cells.
Biochem/physiol Actions
SB-431542 inhibits the TGF-β-mediated activation of SMAD proteins, expression of collagen and fibronectin, cell proliferation and cell motility. It does not inhibit kinases that are activated in response to serum or stress such as ERK, p38 or JNK.
References
1) Laping et al. (2002), Inhibition of transforming growth factor (TGF-beta1-induced extracellular matrix with a novel inhibitor of the TGF-beta type I kinase activity: SB-431542; Mol. Pharmacol., 62 58
2) Inman et al. (2002), SB-431542 is a potent and specific inhibitor of transforming growth factor-beta superfamily type I activin receptor-like kinase (ALK) receptors ALK4, ALK5 and ALK7; Mol. Pharmacol., 62 65
3) Matsuyama et al. (2003), SB-431542 and Gleevec inhibit transforming growth factor-beta-induced proliferation of human osteosarcoma cells; Cancer Res., 63 7791
4) Watabe et al. (2003), TGF-beta receptor kinase inhibitor enhances growth and integrity of embryonic stem cell-derived endothelial cells; J. Cell Biol., 163 1303
5) Stanslowsky et al. (2014), Functional differentiation of midbrain neurons from human cord blood-derived induced pluripotent stem cells; Stem Cell Res. Ther., 5 35
