Figure 3.
Effects of PAK5 gene silencing on cell proliferation and tumorigenicity. HepG2 cells were transfected with Lv-PAK5-shRNA1, Lv-PAK5-shRNA2, or the control Lv-scr-shRNA, and biological assays were performed after 72 h. (A) Cell proliferation was evaluated by the MTT assay. The data are plotted as the OD490-fold versus time over the ensuing five days, where the values at d 1 are set to 1. The data points are the mean±SD (n=5). Cell proliferation was significantly reduced upon PAK5 gene silencing. (B) Transfected cells were analyzed by flow cytometry to determine the distribution of cell cycle phases. The data from the flow cytometry analyses (top panel) were quantified (bottom panel). Reduced PAK5 expression induced cell cycle arrest in the G1 phase (n=5). cP<0.01 vs control. (C) Tumorigenicity was evaluated in vitro by colony-formation assays and the plates were stained with Giemsa. Reduced PAK5 expression severely impaired colony formation (n=3). (D) Tumorigenicity was evaluated in vivo in nude mouse assays. Transfected cells were used to grow xenografts in nude mice. The mice were evaluated for tumor development after three weeks, and photographed as shown.The mice that underwent PAK5 gene silencing showed no visible tumors (n=5).