Cell-Type-Specific Effects of Silibinin on Vitamin D-Induced Differentiation of Acute Myeloid Leukemia Cells Are Associated with Differential Modulation of RXRα Levels

Figure 1

Carnosic acid enhances while silibinin differentially affects 1,25D-induced differentiation of HL60 and U937 cells. Cells were incubated at 4 × 10⁴ cells/mL (a), (b) or 5 × 10⁴ cells/mL (c-f) with 0.1% ethanol (vehicle control) or the indicated test agents, alone or in combination, for 96 h (a), (b) or 24 h (c-f). CD11b and CD14 expression was then determined by flow cytometry (a), (b) or qRT-PCR (c-f). The data are the means ± SE of 5 (a), (b) or 3 (c-f) independent experiments. *𝑃<0.05; ^§𝑃<0.01, or ***𝑃<0.001, combination versus sum of single agents for enhancing effects. ^♦𝑃<0.05, combination versus 1 nM 1,25D alone for inhibitory effects.

(a) HL60

(b) U937

(c) HL60 – CD11b

(d) HL60 – CD14

(e) U937 – CD11b

(f) U937 – CD14