FIG. 2.

(A and B) The PI 3-kinase inhibitors wortmannin (WM, 300 nM) and LY294002 (LY, 25 μM) but not rapamycin (Rap, 30 nM) nearly totally abolish EGF-stimulated upregulation of cyclin D1 mRNA and protein levels and the phosphorylation of pRb. Western (A) and Northern (B) blot analyses were performed 9 h after the addition of EGF with equal amounts of total cellular protein and RNA, respectively. (C) The PI 3-kinase inhibitors are without effect on ERK activities, whereas the MEK inhibitor PD98059 (PD, 30 μM) abolishes the sustained phase of the EGF-stimulated ERK activation. The concentrations of LY and WM are the same as for panels A and B.