Figure 4. Combined treatment with sodium cantharidate and erlotinib decreases phosphorylation of STAT3 and EGFR. (A) MG63 and U2OS cells were treated with DMSO, SC, erlotinib, or a combination of SC and erlotinib for 24 h, and phospho-STAT3 and phospho-EGFR expression was evaluated by western blot. (B) Western blot analysis of phospho-STAT3, Bcl-2, and MMP2 expression in MG63 and U2OS cells treated with DMSO plus empty vector, SC alone, or a combination of SC and constitutively active STAT3 (STAT3-C) for 24 h. Sc, sodium cantharidate; Er, erlotinib. (C) MTT assay results from STAT3-C-transfected MG63 and U2OS cells. (D) Transwell migration assay results from MG63 and U2OS cells expressing STAT3-C.