Fig 1: Carboxylesterase 1 and 2 expression in acute myeloid leukemia (AML) cells and CHR2863-resistant U937 cellsA. CES1 expression (Western blot) in FAB sub-classified (M0, M1, M2, M4, M5) acute myeloid leukemia cells at diagnosis. Superscript symbols refer to matched peripheral blood (PB) and bone marrow (BM) samples. CES1 expression in peripheral blood of healthy controls is depicted for reference. Hep-G2 hepatoma cells serve as control for CES1 and CES2 protein expression. CES2 expression was not observed in the indicated AML samples (not shown). B. mRNA expression of CES1 and CES2 in multiple isolates of CHR2863-resistant U937 cells, including U937/WT, U937/CHR2863(200), and U937/CHR2863(5µM) cells. U937/CHR2863(w/o 1 µM) without CHR2863 for 2 weeks and U937/CHR2863 (w/o 1µM/+1µM) rechallenged with 1 µM CHR2863 for 2 weeks. Mean (± SD) of 3-4 experiments performed in triplicate). (*): p < 0.05. C. Western blots of CES1 (by two different antibodies), CES2 and CES3 protein expression in U937/WT, U937/CHR2863(200), and U937/CHR2863(5µM) cells. KG1 cells served as negative control for CES1 expression [21].