Figure 6
Evidence that EGFR involved in erlotinib/MPT0E028-mediated cell death in erlotinib-resistant cells. (a) mRNA expression level of EGFR in A549 cells was determined by qRT-PCR. Cells were treated with MPT0E028 (M) and/or erlotinib (E) for 72 h, and mRNA expression was analyzed by qRT-PCR as described in the Materials and Methods section. Ectopic EGFR expression protects cells against erlotinib/MPT0E028-induced cytotoxicity and apoptosis. A549 cells (b) and PC9/IR cells (c) were transfected with control vector or Flag-EGFR plasmids and treated with MPT0E028 (M) and/or erlotinib (E) as indicated for 72 h. Cell lysates were subjected to immunoblotting using the indicated antibodies (left panel) and cell viability was measured by the MTT assay (right panel). Error bars represent S.D. Symbols: *P<0.05; **P<0.01; and ***P<0.001 compared with the control group
