MEK Inhibition Sensitizes Precursor B-Cell Acute Lymphoblastic Leukemia (B-ALL) Cells to Dexamethasone through Modulation of mTOR Activity and Stimulation of Autophagy
Fig 6
BCN1 knockdown reduces SEL-mediated sensitization to DEX.
(A) SEMK2 cells were retrovirally transduced with BCN1-specific shRNA or scrambled control (SCR). After selection of stable transfectants, BCN1 knockdown was confirmed by western blot. (B,C) Cells with BCN1 knockdown or control cells were incubated with DEX, (0.05 μg/ml or 2 μg/ml) in the presence or absence of MEK1/2 inhibitor, selumetinib (SEL, 200 nM) for 72h. Apoptosis was assessed by annexinV/PI staining followed by flow cytometry analysis. Representative dot-plots from FACS analysis are shown in B; averaged results from 3 independent experiments with SD are indicated in (C) Statistical difference in responses between mock- and shBCN1-transduced cells were determined using 2-sided Student’s t-test. (D) Beclin-1 expression in cells treated with DEX, SEL or their combination. SEMK2 cells were incubated for 24 h with DEX (0.05 μg/ml), SEL (200 nM) or combination of DEX+SEL and BCN1 expression level was assessed by western blot.