A) PLC/PRF/5 cells were cultured in medium containing either DMSO (1 μl/ml) as control, or resveratrol, phenformin or metformin. The cell number was determined for six consecutive days and results are mean ± SD. B) HepG2 cells were cultured in medium containing DMSO, resveratrol, phenformin or metformin for 2 weeks for assays of colony formation. Results are mean ± SD. C) HepG2 cells were transfected with constructs expressing wild-type AMPK-α2, vector, or an unrelated gene (CAT) as a control, for colony formation assays. Error bars: mean±SD; *, P<0.05 compared with vector control by t-test. D) Two stable shAMPK-α2 expressing PLC/PRF/5 cells (shAMPK#1 (•••) and #2 (---)) and vector control (—) were used to perform cell proliferation assays. The curve shows the proliferation rate of these cell clones. E) shAMPK#1 and #2 stable clones were used for assays of growth in soft-agar. Representative pictures of the colonies are shown and the bar chart indicates quantification (mean ± SD). F) The shAMPK#1 and vector control cells were subcutaneously injected into nude mice, and tumors were allowed to grow for four weeks. The tumor size and weight (n = 5 per group, error bars, mean ± SD) are presented, and a representative picture of tumors with shAMPK and vector control is shown. *P < 0.01, **P < 0.001 (Student t-test) compared with vector.”