Figure 1.

The effect of tryptophan metabolites on the cell viability and the activity of nuclear receptors. Cells were treated for 24 h with the tested compounds at concentrations ranging from 1 nM to 200 µM (indole from 10 µM to 10 mM). (A) Cell viability in LS174T and AZ-AHR cells. The MTT, NR, and LDH assays were performed as described in the experimental section. Data are the means from at least three consecutive cell passages and are expressed as a percentage of the viability (MTT) or cytotoxicity (NR, LDH) of the control cells. (B) The activity of VDR, GR, PPARγ, and AR receptors in stably transfected reporter cell lines. A luciferase assay was performed as described in the experimental section. Vehicle DMSO (0.1% v/v) was used as a negative control, and VD3 (75 nM), DEX (100 nM), 15d-PGDJ (40 µM), or DHT (100 nM) as positive controls, respectively. Data are the means from at least three consecutive cell passages and the effects of tested compounds are expressed as a % of induction by the positive control.