FIGURE 4.

Knockdown of p35 reduces p16-induced flat cell formation in U2OS cells. A, U2OS cells were cotransfected with CMV-p16 and pLKO-p35shRNA-17, -18, -20, or control empty vector, cells transfected with empty vectors were use as control. 16 h after transfection, cells were selected with puromycin at a final concentration of 2 μg/ml. 10 days post-transfection, cells were assayed for SA-β-gal expression and the morphology change in these cells is shown. All images were obtained by using phase contrast microscopy at a magnification of ×10. B, cell area in each group of cells was measured using ImageJ. Means and S.E. of three experiments are presented in the column chart. A p value < 0.001 versus p16 control is indicated by **.