Figure 6. Primary human AML cells are sensitive to Pyrido [4,3-b]quinoxaline.

A. Total WBC were isolated by Ficoll from peripheral blood of five AML patients and treated in vitro with PyQ for 3 days. The percentage of blast cells (CD34⁺ CD33⁺) was shown after a treatment with PyQ (A2 at 6.8μM) or without (control). ≠1, AML3; ≠2, AML1; ≠3, AML2; ≠4, AML1; ≠5, AML4; data gated on viable cells. B. AML CD34⁺ CD33⁺ cells were more sensitive to PyQ treatment than normal primitive hematopoietic CD34⁺ cells purified from cord blood (n = 5 biological replicates). Viability was measured 3 days after treatment with various concentrations of PyQ, IC50 dose (right panel). C. CD34⁺ AML blasts were enriched in lipid rafts compared with CD34⁺ cord blood cells, as assessed by staining with CTB, measured by flow cytometry. Staining with isotype control antibody IgG was shown. D. CD34⁺ CD33⁺ leukemic blasts and CD34⁺ cord blood cells were sorted and analyzed by microscopy. Data showing that CD45 colocalized within lipid rafts (CTB) on CD33⁺ CD34⁺ AML blasts, but not on CD34⁺ cord blood cells. Examples of single cell immunostaining were shown on the left panel. Colocalization scores between CD45 and CTB were reported bellow the immunostaining. Colocalization means were calculated (n > 30 cells) and represented on the right panel. Mean ± SEM. **, P < 0.01; ***, P < 0.001; measured by Student's unpaired t test.