Treatment with PTEN inhibitor SF1670 enhances bacteria-killing capability of neutrophils. (A) In vitro phagocytosis assay. Mouse bone marrow–derived neutrophils were treated with SF1670 at indicated concentrations at 37°C for 30 minutes, washed twice with HBSS, and then incubated with fluorescein isothiocyanate–labeled zymosans (opsonized with mouse serum) at 37°C for 1 hour. Extracellular fluorescence was quenched by trypan blue. Phagocytosis index was expressed as the number of bioparticles engulfed by 100 neutrophils. (B) Binding index was expressed as the number of bioparticles bound to 100 neutrophils. More than 200 neutrophils were counted in each group. Data shown are mean ± SD from 1 experiment representative of 3 experiments. (C) In vitro bactericidal assay. Bone marrow–derived neutrophils were pretreated with indicated amounts of SF1670 as described here, washed twice with HBSS, and then incubated with opsonized live E coli at 37°C. Sterile water was added to lyse neutrophils after 1 hour. Samples were serially diluted and spread on Luria-Bertani agar plates. The numbers of E coli colonies were determined after overnight incubation at 37°C. (D) Gentamicin protection assay. In this experiment, gentamicin was added to kill extracellular bacteria. Data shown are mean ± SD of 3 experiments. *P < .01 vs control.