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. 2014 Apr 1;22(7):2320–2326. doi: 10.1016/j.bmc.2014.02.004

Figure 5.

Figure 5

Gene knockdown of endogenous bcl-2. (A) After lipofectamine 2000-mediated transfection, (B) after unassisted application. The effect of PEG-siRNA conjugates (siRNA-PEG (S), 1/6; siRNA-PEG2 (S/AS), 5/6) was evaluated by qPCR-based quantification of bcl-2 mRNA levels in MCF-7 cells. The indicated siRNAs were either transfected into the cells with lipofectamine 2000 (A), or applied without any uptake-enhancing agent (B). Cells were lysed after 24 h, total RNA was extracted, transcribed into cDNA, and quantified with qPCR. Bcl-2 levels were normalized to the reference gene RNA polymerase II, which was shown not to be influenced by siRNA or the transfection procedure. After lipofectamine-mediated delivery, efficient gene silencing occurred with both modified and unmodified siRNAs (p < 0.05 compared to untreated cells) with virtually no difference between PEGylated (1/6 and 5/6) and non-PEGylated siRNA (1/2) duplexes. In contrast, no gene silencing was detected when either of the siRNAs were applied without transfection enhancing agent, indicating no unassisted (gymnotic) uptake takes place. All values are reported relative to untreated cells (n = 3), error bars represent the standard deviation.