(A–C) Immunoblotting analysis of whole-cell lysates of equal total protein prepared from (A) NIH3T3/hEGFR fibroblasts pre-treated with or without 5 μM of 6, 10, 20 or 22 for 3 h prior to stimulation with 1 μg/ml EGF for 12 min, (B) U251MG cells treated with 5 μM 6, 10 or 22 for 0–24 h, or (C) U251MG cells treated with 5 μM 6, 10 or 22 for 3 h in the absence or presence of 10–300 μM Na3VO4 and probing for pStat3, Stat3, pStat1, Stat1, pStat5, Stat5, pErk1/2, Erk1/2, pS-Akt, Akt, pJAK2, JAK2, SOCS3, PTP1B, β-actin or GAPDH. Positions of proteins in gel are labeled; control lanes (0, −) represent whole-cell lysates prepared from 0.025% DMSO-treated cells. Data are representative of 2–4 independent determinations.