Figure 2

The anti-proliferative effect of AICAR on ALL cells is mediated via activation of AMPK. (A) Western blot analysis of phosphorylated AMPK (P-AMPK, Thr172) expression in CCRF-CEM, NALM6, REH, and SupB15 cells treated with various concentrations of AICAR (0 – 2.0 mM). Total protein was extracted from AICAR-treated cells and AMPK and P-AMPK were immunodetected using specific antibodies. Equal amounts of protein (50 μg) were loaded per lane as confirmed by β-actin level. Density value of P-AMPK bands were normalized to level of AMPK and expressed relative to control. (B) Cell proliferation assays of ALL cells treated for 18 h with AICAR alone (0.25 mM for CCRF-CEM, NALM6, REH, and 1.0 mM for SupB15), the adenosine kinase inhibitor iodotubericidin alone (Iodo, 0.1 μM), or both agents together (Iodo + AICAR). Growth inhibition was determined using the tetrazolium (MTS) reduction assay. Values are expressed as a percentage relative to those obtained with untreated control cells (mean ± SEM). Data are representative of at least three independent experiments. #, p < 0.001 for AICAR vs. Iodo + AICAR.