Mass spectrometry proteomics. Sample preparation. MV4;11 cells in RPMI (Invitrogen) were seeded at 5 × 10 6 cells on a 100mm plate 24 h before treatment. Cells were treated in triplicate by addition of test compound. After 4 h, the cells were centrifuged at 250g for 5 min and washed twice with 12mL of cold PBS. Cells were lyzed in 500µL of 100mM TRIS pH 8.0, 4% (w/v) SDS supplemented with protease inhibitor cocktail (Roche). The lysate was pulse sonicated briefly and then centrifuged at 15,000g for 10 min at 4°C. Samples were quantified using a micro BCA protein assay kit (Thermo Fisher Scientific) and 200µg of each sample was processed and digested using the filter aided sample preparation method followed by alkylation with iodoacetamide digestion with trypsin as previously described . The samples were then desalted using a 7mm, 3mL C18 SPE cartridge column (Empore, 3M) and labeled with TMT 10-plex Isobaric Label Reagent Set (Thermo Fisher Scientific) as per the manufacturer's instructions. After labeling, the peptides from the nine samples were pooled together in equal proportion. The pooled sample was fractionated using high pH reverse-phase chromatography on an XBridge peptide BEH column (130Å, 3.5µm, 2.1 × 150mm, Waters) on an Ultimate 3000 HPLC system (Thermo Scientific/Dionex). Buffers A (10mM ammonium formate in water, pH 9) and B (10mM ammonium formate in 90% acetonitrile, pH 9) were used over a linear gradient of 5 to 60% buffer B over 60 min at a flow rate of 200µL min -1 . Then, 80 fractions were collected before concatenation into 20 fractions on the basis of the ultraviolet signal of each fraction. All the fractions were dried in a Genevac EZ-2 concentrator and resuspended in 1% formic acid for mass spectrometry analysis.