STAT3 inhibitor W36 is a potent, selective STAT3 inhibitor with SPR KD of 323.3 nM, inhibits IL-6/JAK/STAT3 signaling pathway with IC50 of 0.87 uM in HEK-Blue-IL-6 cell model.
W36 demonstrates dual suppression of STAT3 phosphorylation and proliferation in the STAT3-overactivated TNBC cell lines MDA-MB-231 (IC50 = 0.61 μM) and MDA-MB-468 (IC50 = 0.65 μM).
W36 displays strong anti-proliferative effects against the taxol-resistant strains MCF-7/T and MX-1/T with IC50 of 1.73 and 0.75 uM respectively.
W36 inhibits STAT3 phosphorylation at Y705 in a dose- and time-dependent manner, but not  STAT1 or STAT5.
W36 also shows no activity against classic JAK subfamily kinases (JAK1, JAK2, JAK3, TYK2 and SRC).
W36 inhibits STAT3 Y705 phosphorylation and downstream target gene expression in MDA-MB-231 and MDA-MB-468 cells.
W36 (7.5, 10 mg/kg, i.p.) or (100 mg/kg, p.o.) exhibits antineoplastic efficacy in MDA-MB-231 xenograft model nude mice, potent than Stattic.