Nifuroxazide inhibits STAT3, Jak2, and Tyk2 tyrosine phosphorylation. (A) U266 cells were incubated with the indicated concentration of nifuroxazide for 24 hours, after which whole-cell lysates were prepared, and Western blot analysis was performed using antibodies specific for tyrosine-phosphorylated STAT3 (p-tyr STAT3) and total STAT3. (B) U266 cells were incubated for the indicated times with 10 μM nifuroxazide. Western blots were performed for tyrosine-phosphorylated STAT3, serine-phosphorylated STAT3 (p-ser STAT3), and total STAT3. (C) INA6 cells were incubated with 10 μM nifuroxazide or vehicle for 6 hours, after which immunoprecipitation was performed followed by Western blotting with the indicated antibodies. Quantitation of bands is shown for each panel.