Fig. 2.

EGFR expression was decreased after transfection of Ex19del DNAzyme into lung cancer cells. Oligo DNAs (100 nM) such as scrambled DNAzyme and Ex19del DNAzyme were transfected into PC9/GR lung cancer cells (5 × 10⁵ cells). 48 h after transfection, total RNA and cellular proteins were obtained for analysis. (A) Real-time PCR for detection of EGFR cDNA was performed in DNAzyme-transfected cells, as described in the graph. cDNA amplified from EGFR transcripts was relatively quantified by normalization to control cells that were untreated. **P < 0.01. (B) Western blot analysis revealing the inactivation of EGFR protein in DNAzyme-transfected cells. Histograms show the levels of total EGFR including phospho-EGFR (black bar) expressed relative to the loading control (β-actin) and phospho-ERK1/2 (white bar) relative to total ERK1/2, which were normalized to the non-treated control. **P < 0.01. (C) The viability of cancer cells treated with different DNAzymes and EGFR siRNA was measured using methylene blue 48 h after treatment with DNAzyme or siRNA.