SP600125, 5 mg

From STEMCELL Technologies, this small molecule is a potent and reversible inhibitor of c-Jun N-terminal kinase (JNK) with an IC₅₀ of 0.11 µM (Bennett et al.), acting against the JNK1, JNK2, and JNK3 isoforms. The three JNK isoforms are members of the MAP kinase superfamily that induce expression of immediate-early genes in response to specific stress and inflammatory signals, modulating cell proliferation, apoptosis, differentiation, and autophagy. The compound is cell-permeable and dose-dependently inhibits c-Jun phosphorylation in cells, blocking the expression of COX-2 and TNF-α in monocytes and IL-10, TNF-α, and IFN-γ in T-cells (Bennett et al.).

Also known as NSC 75890, Pyrazolanthrone, or 1PMV, this anthra[1,9-cd]pyrazol-6(2H)-one has a molecular weight of 220.2 g/mol and a chemical formula of C₁₄H₈N₂O (CAS Number: 129-56-6). It is supplied as a crystalline solid with a purity of ≥ 98% and is stable at -20°C as supplied when protected from prolonged exposure to light. Reported solubility is ≤ 90 mM in DMSO and ≤ 2.2 mM in absolute ethanol, with low solubility in aqueous media. Stock solutions are recommended to be prepared fresh and stored at -20°C; final DMSO concentration should be kept below 0.1% when used as a cell culture supplement.

Published applications include direct lineage reprogramming of fibroblasts to mature neurons when used in combination with CHIR99021, RepSox, Forskolin, Gö6983, Valproic Acid, and Y-27632 (Hu et al.). In differentiation studies, the inhibitor has been reported to inhibit BMP9-induced osteogenic differentiation in cultured mouse mesenchymal stem cells and primary bone marrow stromal cells (Zhao et al.), promote adipogenic and repress osteogenic differentiation of human MSCs (Bilkovski et al.; Liu et al.; Qiu et al.; Tominaga et al.), and cause cell death while inhibiting neurogenesis when added during early stages of neuronal culture (Tiwari et al.).