Figure 4.

Isoform-selective PI3K inhibitor treatment demonstrates time-dependent inhibition of PI3K signaling. (Top) A549, PC9 and H1650 cells were treated with 1μM isoform selective inhibitors in RPMI 1640 containing 1% serum and collected at indicated times after drug addition. Untreated controls represent serum-starved cells collected at times post-serum addition. (Bottom) Cell lines were treated with 1μM ZSTK474 as in the top panel. Samples were collected for immunoblotting with indicated antibodies as described above. α-tubulin serves as the normalization control.