Figure 4. Acetate secretion is linked to ROS transfer from AML to stromal cells.

(A) Extracellular acetate levels in SKM-1 (black) and MS-5 cells cultured alone (dark grey) and in co-culture (light grey) for 24 hr in a control medium, medium with 50 µM H₂O₂ or medium with 5 mM NAC. (B, C and D) Intracellular ROS levels measured by H₂DCFDA staining in B and D AML cells or C primary patient-derived AML cells and MS-5 cells cultured alone and in co-culture in B and C direct contact. For A, and B, bars represent the mean of n=3 independent experiments and error bars represent standard deviations. For A, a Dunnett’s multiple comparisons test was performed comparing each condition (H₂O₂/NAC) was compared to untreated; for B and D, an unpaired t test with Welch’s correction was applied comparing co-culture conditions to cells cultured alone. p-Values are represented by n.s. for not significant, * for p-value <0.05, and ** for p-value <0.01.

Figure 4—figure supplement 1. Acetate secretion in thiamine free medium and after modulating ROS levels.

(A), Extracellular acetate levels in MS-5 cells cultured in control medium (black) or in thiamine-depleted medium (grey) after 24 hr. (B), Extracellular acetate levels in Kasumi-1 (navy blue) and HL-60 (red) cultured alone and in co-culture (light blue and light red) for 24 hr in a control medium, medium with 50 µM H₂O₂ or medium with 5 mM NAC. Acetate levels for HL-60 cells cultured alone or under co-culture with 50 µM H₂O₂ are not shown as treatment 50 µM H₂O₂ severely impaired their viability. N.A.=not analysed. (C), Extracellular acetate levels in SKM-1 cultured alone and in co-culture for 24 hr in a control medium and medium with 100 µM or 500 µM catalase. For A and B each bar represents the mean of n=3 independent experiments and error bars represent standard deviation. For A and C, an unpaired Student’s t-test was applied for each condition. For B, a Dunnett’s multiple comparisons test was performed for Kasumi-1 and a Sidak’s multiple comparisons test was performed for HL-60. p-Values are represented by n.s. for not significant. * for p-value <0.05, ** for p-value <0.01 and *** for p-value <0.001.