IWP-4

IWP-4 is a small molecule Wnt inhibitor with an IC₅₀ of 25 nM. IC50 & Target: IC50: 25 nM (Wnt)^[1] In Vitro: IWP-4 is a small molecule Wnt inhibitor with an IC₅₀ of 25 nM. IWP-4 induces the expression of cardiac markers, including cardiac troponin I (CTNI) and cardiac myosin heavy chain bright cells (MYH^{hi +}). IWP-4 also results in the appearance of beating foci (0.44±0.10 SEM beats per second), which is absent in all cultures not receiving IWP-4. Further, flow cytometric analysis shows that there are significantly more MYH^{lo +} cells in IWP-4 treated cultures (P<0.0002) compare with untreated cultures at day 16, being 17.0±1.3 SD% and 5.4±1.4 SD%, respectively. Quantification of NKX2-5 protein expression shows that 63% (481/817) of IWP-4 treated cells display nuclear NKX2-5 expression^[1]. Mesenchymal precursor cells (MPCs) treated with IWP-4 show no significant changes in the expression of AXIN2, CTNNB1 and GSK3B as compare to osteogenic medium alone on day 7, but MPCs treated with IWP-4 express elevates levels of DKK1 and GSK3β on day 21. IWP-4 also causes a significant down regulation of SPARC and COL1A1^[2].