Figure 4

Enhanced expression of SKP2 by high expression plasmid restores Sjp40-induced senescence in LX-2 cells. (a) LX-2 cells were transfected with pcDNA3.1 or pcDNA-SKP2 and additionally treated with or without Sjp40 for 48 h. The protein levels of SKP2, P27, P-Rb and α-SMA were investigated by Western blot assay and date were expressed as the mean ± SEM of three or more independent trials. *p < 0.05 compared to the control group; & p < 0.05 compared to the pcDNA3.1 group. $ p < 0.05 compared to the control group; # p > 0.05 compared to SKP2-treated group. (b) Over-expression of SKP2 rescued the Sjp40-induced senescence analyzed by SA-β-Gal assay (original magnification 200×) and the graph also reveals quantitative analysis of the percentage of SA-β-Gal positive cells (%) expressed as the mean ± SEM of three or more independent trials. *p < 0.05 compared to the control group. Bar: 50 micrometers.