A, for cell cycle analysis, cells (2.5 × 105/well) were treated with 125μg/mL MM-121, 62μg/mL cetuximab and the combination for 72 hours and then analyzed by flow cytometric analysis. The percentage of cells in the G0-G1, S, and G2-M phases of the cell cycle are shown. B, cell lysate in (A) was collected and immunoblotted for cell cycle related cyclinD1 and cyclinE. C, for apoptosis assay, cells were treated for 72 and 96 hours with the same doses of drugs as cell cycle assay and then analyzed by flow cytometry. D, cell lysates from the same treatment as apoptosis assay were collected and immunoblotted for caspase3 and PARP. All data are expressed as mean ± SE from 3 independent experiments. (*indicates p<0.05, ** indicates p<0.01 vs. ctrl).