Lyophilized bovine plasma

AGP purified from human or bovine plasma (Sigma) was resuspended in unsupplemented RPMI1640 (Gibco) at 10 mg/mL for working stocks. Recombinant human serum albumin (Sigma) was resuspended in RPMI1640 at 100 mg/mL. Lyophilized bovine plasma (Sigma) was reconstituted in sterile PBS (Gibco). TTT-3002 was a generous gift of TauTaTis, Inc. Lestaurtinib, midostaurin, sorafenib, and quizartinib were purchased from LC Laboratories. Each FLT3 TKI was dissolved at 10 mmol/L in 100% sterile-filtered dimethylsulfoxide (DMSO, Sigma). Mifepristone (Sigma) was dissolved at 100 mmol/L in 100% DMSO. Trihexyphenidyl hydrochloride (Selleckchem) was dissolved at 100 mmol/L in methanol. For cell-based assays, working stocks of 10 μmol/L were prepared for each drug in RPMI1640 supplemented with 0.1% DMSO and 0.2% BSA. For spectrophotometric studies, working stocks of 10 μmol/L were prepared using PBS without sera or albumin. ANS (Sigma) was dissolved in DMSO at 200 mmol/L and then diluted to 400 μmol/L with PBS (0.2% DMSO, final). Western blot analysis was performed using the FLT3 S-18 antibody (Santa Cruz Biotechnology) and for other proteins as indicated (Cell Signaling Technology).