Activated Forms of H-RAS and K-RAS Differentially Regulate Membrane Association of PI3K, PDK-1, and AKT and the Effect of Therapeutic Kinase Inhibitors on Cell Survival

摘要: The abilities of mutated active RAS proteins to modulate cell survival following exposure ionizing radiation and small molecule kinase inhibitors were examined. Homologous recombination in HCT116 cells delete the single allele K-RAS D13 resulted a line that exhibited an ∼75% reduction basal extracellular signal-regulated 1/2, AKT, c- jun -NH2-kinase 1/2 activity. Transfection lacking with H-RAS V12 restored AKT activity levels but did not restore phosphorylation. In expressing V12, caused prolonged intense activation AKT. Inhibition function, blockade phosphatidylinositol 3-kinase (PI3K) function using interfering RNA/small-molecule inhibitors, or expression dominant-negative abolished radiation-induced activation, radiosensitized these cells. PI3K significantly radiosensitize parental Inhibitors PH domain including perifosine, SH-(5, 23-25) ml-(14-16) reduced plating efficiency dose-dependent fashion. perifosine enhanced radiosensitivity cells, whereas SH ml series failed promote toxicity. PI3K, PDK-1, membrane associated, D13, only PDK-1 was bound. associated phosphorylated at Y373/376, which by Src family inhibitor PP2. OSU-03012 PP2 profoundly increased radiosensitivity. had modest inhibitory effects on A RNA generated against PDK1 also V12. Collectively, our data argue molecular inhibition signaling enhances D13. Small-molecule agents blocked stimulated and/or variable enhancing tumor