Figure 3. Changes in the levels of p27^kip and p21cip during apoptosis. A, B: Apoptosis was induced in rabbit corneal primary epithelial (RCPE) cell cultures with staurosporine (STS) as described in the Methods section. E: Subconfluent (80%–90%) RCPE cultures were starved overnight with Dulbecco’s Modified Eagle Medium with Ham’s F-12 (DMEM/F-12)/0.25% fetal calf serum (FCS) and then treated with 20 ng/ml HGF or KGF for 10 or 24 h. Levels of p27^kip and p21^cip in cellular extracts at different time points were determined with western immunoblotting using specific antibodies. Quantification of p27^kip and p21^cip levels in apoptosis cultures (C–D) and HGF- and KGF-treated cultures (F) was performed with densitometry. Data are representative of results obtained from three similar experiments. Data shown are mean±standard deviation (SD). *p<0.05, STS versus corresponding control at 10 or 24 h, #p<0.05, control versus HGF or KGF at 10 or 24 h.