Effect of the EGFR pathway on Cox-2 mediated invasiveness of MCF-7/DOX cells. (A) Western blot analysis of EGFR expression in MDA-MB-231, MCF-7, MCF-7/DOX, and T-47D cells. (B) Western blot analysis of MCF-7/DOX and MDA-MB-231 cells that were transfected with control or EGFR siRNA. (C) Western blots of lysates from MCF-7/DOX cells treated with EGF (100 ng/mL) for the indicated times (0-12 h). (D) Western blot analysis from MCF-7/DOX cells that were treated with gefitinib (2 μM) for 24 h And EGF (100 ng/mL) was added for an additional 8 h. (E) Cell invasion assay of MCF-7/DOX cells treated with 2 μM gefitinib treatment for 18 h. Cell proliferation was not affected by treatment with 2 μM gefitinib for 24 h. *P < 0.01 (t-test).