SIS3, 1 mg

A cell-permeable selective small-molecule research tool from STEMCELL Technologies, SIS3 inhibits transforming growth factor β1 (TGF-β1)-dependent SMAD3 phosphorylation and SMAD3-mediated cellular signaling, with an IC₅₀ of 3 µM. It shows selectivity, with no reported effect on SMAD2, p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), or phosphoinositide 3-kinases. The compound is supplied as a crystalline solid of ≥98% purity (molecular formula C₂₈H₂₇N₃O₃; molecular weight 453.5 g/mol).

Stock solutions can be prepared in DMSO or absolute ethanol at concentrations up to 65 mM; for example, a 10 mM DMSO stock uses 0.5 mg in 110 µL of DMSO. Final DMSO concentration in culture should not exceed 0.1% to avoid cell toxicity. The product remains stable for 12 months from the date of receipt when stored at −20 °C and protected from prolonged light exposure. Published applications include facilitating the production of anterior ectoderm from mouse induced pluripotent stem cells (Oshima et al., 2010) and inhibiting myofibroblast differentiation of normal human dermal fibroblasts (Jinnin et al., 2006).