Figure 4.

Western blot analysis. After cells were treated with or without the combination of IFN-α_2b (10 K IU/ml) and PDF (250 μg/ml) for 72 h, cell lysates (7 μg) obtained from control and the IFN-α_2b/PDF-treated cells were analyzed for CDK2, CDK4, CDK6, cyclin D₁, and cyclin E using Western blots. Significantly (>60%) reduced expressions of all these regulators following the IFN/PDF treatment are apparent on the blots.