Figure 4. Downregulation of p27kip expression by hepatocyte growth factor (HGF) and keratinocyte growth factor (KGF) during apoptosis. Rabbit corneal primary
epithelial (RCPE) cell cultures in Dulbecco’s Modified Eagle Medium with Ham’s F-12 (DMEM/F-12)/0.25% fetal calf serum (FCS)
were pretreated with 20 ng/ml HGF or KGF for 30 min before staurosporine (STS) was added. Cultures were further incubated
in the presence of STS (10 ng/ml) for 2 h. Then the medium was removed, and fresh medium containing HGF or KGF but no STS
was added, and incubation continued for 8 h (A) to 22 h (B). Levels of p27kip in cellular extracts at different time points were determined with western immunoblotting using monoclonal p27kip antibody and quantified with densitometry (C and D). Similar results were obtained in two additional experiments. Data shown are mean±standard deviation (SD). *p<0.05, control
versus HGF or KGF, #p<0.05 STS versus STS+HGF or STS+KGF.