Figure 2. Effects of XAF1 on the upregulation of cellular senescence in young HMVECs.

A. Young cells were transduced with XAF1 or negative control lentiviruses and incubated for 3 days. XAF1 mRNA expression levels were measured by semi-quantitative PCR and XAF1, cyclin A, p53 and p21 protein levels were detected by Western blot analysis. B. Cell proliferation was measured by cell counting and C. the percentages of SA-β-gal positive cells were analyzed. *p < 0.05 and ** < 0.01 versus the vector group. D. XAF1-transduced cells were stained with Annexin V-FITC and propidium iodide (PI). To measure apoptosis, fluorescence intensities of Annexin V-FITC were analyzed by flow cytometry. Etoposide (EP, 100 μM) was used as a positive treatment. Cleaved caspase 3 activity was analyzed by Western blot. E. Cell cycle profiles were analyzed by PI staining and flow cytometry. Values are expressed as the mean ± SD of three independent experiments. Representative data from three independent experiments are shown. *p < 0.05 and **p < 0.01 versus the vector group. V, control vector lentivirus-transduced cells; XAF1, XAF1 lentivirus-transduced cells.