Figure 4. Expression and evaluation of WT human CYP24A1 in target cells.
A 1,25D-VDR luciferase transcription system was successfully developed to detect levels of 1,25D inactivation via the CYP241 enzyme. In a mammalian two-hybrid assay system, HCT-116 cells were transfected with either pSG5-empty (designated by “−”) or pSG5-CYP24A1 (designated by “+”) followed by treatment with either 25D or 1,25D. (A) Cells were transfected as indicated and treated with either 100 nM 25D or 1 nM 1,25D. (B) Cells were transfected with increasing concentrations of pSG5-CYP24A1 plasmid and treated with 1 nM 1,25D. Data are representative of three independent experiments with triplicate samples in each group.