Stat3 inhibitor H182

Stat3 inhibitor H182 is a potent, selective STAT3 inhibitor, inhibits Stat3 DNA-binding activity with IC50 of 0.66 uM.Stat3 inhibitor H182 shows selective inhibition of Stat3:Stat3 DNA-binding activity, over the inhibition of Stat1:Stat3 (IC50 of 3.4-8.3 μM), with far lower potencies against Stat1:Stat1 (IC50 > 15.8 uM) and Stat5:Stat5 activities (IC50 >19.1 uM).Stat3 inhibitor H182 irreversibly and covalently binds (KD=1.97 uM, ITC) to Stat3 key residues Cys426 and Cys468.Stat3 inhibitor H182 inhibits constitutive and ligand-induced Stat3 activation (pY705Stat3) and blocks Stat3 nuclear accumulation with no change in Stat3 protein levels in breast cancer cells, with little or no effects on pS727Stat3, Stat1, JAK2, EGFR, Shc, Erk1/2, Src, or Akt induction.Stat3 inhibitor H182 inhibited anchorage-dependent and independent growth (MDA-MB-231, IC50=1 uM), induced apoptosis, and suppressed Stat3 target gene expression in TNBC cells harboring constitutively-active Stat3.Stat3 inhibitor H182 inhibited growth of breast tumors in mice, enhanced response to radiation and prolonged survival.