An increase in oxidative stress downstream of mTORC1 but not AKT causes a proliferative defect in cancer cells with acquired resistance to PI3K/mTOR inhibitors

Proteomics and phosphoproteomics analysis of MCF7 cells sensitive and resistant to the PI3K inhibitor GDC-0941. The analysis was done for parental and 3 resistant cell lines maintained in the presence or the absence of the drug. One of the resistant cell lines (G2) was also treated with vehicle or the kinase inhibitors GDC0941, MK-2206 and Ku-0063794 for 2h. The proteomics analysis of sensitive and resistant MCF7 cells in basal conditions and phosphoproteomics analysis of the G2 cells in the presence of inhibitors of the PI3K pathway were run in a nano flow ultrahigh pressure liquid chromatography (UPLC, nano Acquity, Waters) coupled to an LTQ-Orbitrap XL mass spectrometer (Thermo Fisher Scientific). The phosphoproteomics study of sensitive and resistant MCF7 cells in basal conditions was run in a Dionex UltiMate 3000 RSLCnano coupled to an Orbitrap Q Exactive Plus mass spectrometer (Thermo Fisher Scientific).