1. Fig. 1 LB100 and LB102 specifically inhibit PP2A phosphatase activity and the growth of BCR-ABL+ cells.
LB100 and LB102 specifically inhibit PP2A phosphatase activity and the growth of BCR-ABL+ cells. (A) The inhibitory effects of LB100 and LB102 on phosphatase activity of protein phosphatase 2A (PP2A) were measured in the presence of various concentrations of either LB100 or LB102 for 15 min in a phosphatase assay. (B) K562 cells were treated with 5 μM LB100/LB102, and PP2A phosphatase activity was measured at the time points indicated using a PP2A immunoprecipitation (IP) phosphatase assay kit (left). K562 and K562 imatinib mesylate–resistant (K562-IMR) cells were treated with 5 μM LB100/LB102, and BV173 cells were treated with 2.5 μM LB100/LB102 and then assayed for phosphatase activity after 12 hours (right). (C) K562 and K562-IMR cells were treated with IM (0.5 μM) with or without LB100/LB102 (2.5 or 5 μM) for 48 hours and assayed for cell viability. The cell lines were treated with 0.5 μM IM (K562) or 5 μM IM (K562-IMR) with or without 5 μM LB100/LB102 and assayed for cell proliferation (D) and apoptosis (E). The fraction of apoptotic cells was determined by annexin V+ staining. (F) Representative Western blot analysis of total and cleaved caspase 8 and caspase 3 in K562 cells after 24 and 48 hours of treatment. Data are mean and SEM from three independent experiments. P values were calculated using paired two-tailed Student’s t test. Ctrl, untreated cells.
Damian Lai et al., Sci Transl Med 2018;10:eaan8735
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