Figure 7
The knockdown of EGFR expression reduces the cell death effect of ND-PTX-Cet in human CRC cells. (a) HCT116 cells were plated at a density of 7 × 105 cells per 60-mm Petri dish in complete medium for 18–20 h. The cells were transfected with or without EGFR siRNA (10–40 nM for 48 h) in serum-free medium for 6 h at 37 °C. Then, the equal amount with 20% FBS medium was added without removing the transfection mixture, and incubation proceeded for an additional 48 h. At the end of treatment, the total protein extracts were prepared for western blot analyses using specific antibodies, including rabbit anti-EGFR and mouse anti-actin. (b) HCT116 cells were transfected with or without EGFR siRNA (10 nM) for 48 h and then the cells were treated with or without ND-PTX (1 μg/mL) and ND-PTX-Cet (1 μg/mL) for 48 h. The treated cells were immediately observed under a live-cell imaging microscope. (c) At the end of treatment, the total cell numbers were collected and the percentages of cell death were determined by automatic cell counter. The bar represents the mean ± S.E. # p < 0.05 indicates significant difference between the control and EGFR siRNA by treatment with ND-PTX-Cet. **p < 0.01 indicates significant difference between ND-PTX and ND-PTX-Cet by transfection with control siRNA.
