Figure 3.

Effect of cell doubling time on the duration of luciferase knockdown by siRNA in vitro. (A) Experimental results using Oligofectamine to deliver 100 nM siRNA to luciferase-expressing cells with a range of doubling times (dt). Data points represent the ratio of the average luciferase signal intensity from triplicate wells receiving siGL3 and siCON1 on day 0. Squares, Neuro2A-Luc (dt = 0.8 d); diamonds, LNCaP-Luc (dt = 1.4 d); triangles, HeLa-Luc (dt = 1.6 d); circles, CCD-1074Sk-Luc (nondividing). (B) Luciferase knockdown after siRNA transfection predicted by the mathematical model using the baseline in vitro parameters given in Table 2 with the initial number of dividing and nondividing cells equal to 5 × 10⁴ and 1.5 × 10⁵, respectively, a transfection time of 5 h, and a transfection efficiency of 90%.