C188

C188 (CPD188) is a STAT3 inhibitor with anticancer effects. C188 inhibits STAT3 SH2/pY-peptide binding (IC₅₀ of 20 µM against pY-peptide binding) and IL-6-mediated STAT3 phosphorylation. C188 is selective for STAT3 over STAT1. C188 inhibits nuclear-to-cytoplasmic translocation of Stat3. C188 shows highly active induces apoptosis in breast cancer cell lines with constitutive Stat3 activation (EC₅₀s of 0.73 µM, 3.96 µM, and 7.01 µM in MDA-MB-468, MDA-MB-231, and MDA-MB-435 cultures, respectively)^[1]. In Vitro:C188 (CPD188) (0-300 μM; 24 h) shows preferentially induces apoptosis in cultures expressing constitutively active STAT3 (EC₅₀s of 0.73 µM, 3.96 µM, and 7.01 µM in MDA-MB-468, MDA-MB-231, and MDA-MB-435 cultures, respectively), while being less effective against cells without constitutively active STAT3 (EC₅₀s of 15.5 µM and 17.19 µM in MDA-MB-453 and MCF7 cultures, respectively)^[1].
C188 (1-300 µM; pretreated for 60 min, then stimulated with IL-6 (30 ng/mL) for 30 min) inhibits IL-6-mediated tyrosine phosphorylation of Stat3 in the immunoblot assay^[1].