Figure 4. Western blot analysis and real-time PCR show that PD 0332991 and gefitinib down-regulate the expression of cell cycle-associated markers.

A-B. PC-9 cells treated with PD 0332991 alone for 24 and 48 hr. C-D. PC-9/AB2 cells treated with PD 0332991 alone for 24 and 48 hr. E-G. The expression of RB-E2Fs pathway proteins in PC-9 and PC-9/AB2 cells; The combination of PD 0332991 and gefitinib treatment in PC-9/AB2 cells for 24 hr resulted in changes in the RB-E2Fs and Akt/MAPK pathways.