Down-regulation of EGFR protein levels and phenotypic consequences of EGFR knockdown. (A) Western blot was performed to determine the down-regulation levels of EGFR protein. (B) Cell viability was detected by CellTiter-Blue® Cell Viability Assay. (C) Caspase-3/7 activity was measured by Apo-ONE® Homogeneous Caspase-3/7 Assay. (D, E) Viable and apoptotic cells were counted with Hoechst 33342 and propidium iodide (PI) double fluorescent chromatin staining. The aggregate results are consistent with the mRNA knockdown results obtained in the RT-qPCR experiments and confirm that of the siRNAs tested, the s1247 is the most powerful siRNA on H358 cells to down-regulate the EGFR protein level, inhibit the cell viability and induce apoptosis in comparison to other siRNAs (Results see Table 1). Idem as above.