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 5
Effects of carnosic acid, silibinin, and 1,25D, alone and in combination, on the Nrf2/ARE signaling pathway in HL60 and U937 cells. (a), (b) Cells were transiently transfected with 4xARE-luc and Renilla luciferase reporter constructs followed by treatment with 0.1% ethanol (control) or indicated test agents for 24 h. tert-Butylhydroquinone (tBHQ), a classical Nrf2/ARE activator [23], was used as the positive control. The relative 4xARE-luc activity (means ± SE) was calculated from the data of 4 individual experiments performed in triplicate. **, combination versus sum of single agents. (c), (d) Cells (1 × 105 cells/mL) were treated with 0.1% ethanol (control) or the indicated test agents, for 48 h. Protein expression was then determined by Western blotting. Calreticulin (CRN) was used as the protein loading control. Representative blots of at least 3 independent experiments are shown.
