SB505124

SB-505124 is a selective inhibitor of TGFβR with IC50 of 129 nM and 47 nM for ALK4, ALK5, respectively, and it does not inhibits ALK1, 2, 3, or 6 but ALK7.

Signaling Pathways >> TGF-beta/Smad >> TGF-β Receptor

Research Areas >> Cancer

IC50: 129 nM (ALK4), 47 nM (ALK5)

SB-505124 demonstrates no toxicity to renal epithelial A498 cells at concentrations up to 100 μM for 48 h. 505124 inhibits the closely related ALK4 with an IC50 value of 129±11 nM (about 2.5-fold less sensitive than ALK5) but does not inhibit ALK2 at concentrations up to 10 μM. SB-505124 (1 μM) inhibits the TGF-β-induced phosphorylation of Smad2 in all three of these cell lines in a concentration-dependent fashion. SB-505124 (1 or 5 μM) potently inhibits TGF-β-induced activation of JNK/SAP, extracellular signal-regulated kinase 1/2, and p38 despite the different patterns of activation in these cells[1]. SB-505124 (10 µM) impairs Smad2 phosphorylation and CTGF and α-SMA expression in vitro[2]. SB-505124 susspresses CTGF and α-SMA observed by immunofluorescence. Cell outgrowth from explants dissected from eyes to which SB-505124 is applied during GFS is robust while outgrowth is poor from those treated with MMC[3].

Briefly, phospho-p38 is immunoprecipitated from 200 μg of cell lysates with an immobilized phosphor-p38 antibody overnight at 4°C. p38 kinase activity is measured using 2 μg of ATF-2 fusion protein as the substrate with addition of 200 μM ATP. After a 30-min incubation at 30°C, the reaction is terminated with LaemmLi sample buffer, and the proteins are boiled and resolved by 10% SDS-polyacrylamide gel electrophoresis, transferred to nitrocellulose membrane, and immunoblotted with phospho-ATF-2 antibody.

Cell viability is measured as described previously or by using the modified tetrazolium salt WST-1. Approximately 2000 cells are seeded in 96-well dishes in 100 μL of 0.2% FBS phenol red-free media overnight. The cells are treated with 50 μL of SB-505124 (to achieve the final concentrations indicated) for 30 min before being treated with or without TGF-β1 and TNF-α to a final volume of 200 μL. Cell growth is measured at the indicated time points by incubating each well with 10 μL of WST-1 for 3 h at 37°C. Metabolically active cells cleave WST-1 to water-soluble formazan, which is directly quantitated with an enzyme-linked immunosorbent assay plate reader. Each experiment is done at least twice, and treatment for each cell line is done in triplicate.

[1]. DaCosta Byfield S, et al. SB-505124 is a selective inhibitor of transforming growth factor-beta type I receptors ALK4, ALK5, and ALK7. Mol Pharmacol. 2004 Mar;65(3):744-52.

[2]. Sutariya V, et al. Thermoreversible gel for delivery of activin receptor-like kinase 5 inhibitor SB-505124 for glaucoma filtration surgery. Pharm Dev Technol. 2013 Jul-Aug;18(4):957-62.

[3]. Sapitro J, et al. Suppression of transforming growth factor-β effects in rabbit subconjunctival fibroblasts by activin receptor-like kinase 5 inhibitor. Mol Vis. 2010 Sep 16;16:1880-92.

SB431542 | Galunisertib (LY2157299) | A 83-01 | LY2109761 | LDN193189 | RepSox | SB525334 | Vactosertib (TEW-7197) | DMH-1 | GW788388 | LY364947 | LY3200882 | H-Leu-Ser-Lys-Leu-NH2 trifluoroacetate salt | ITD-1 | K 02288