Fig. 5.

Inhibition of CYP4F enzymes decreases the formation of the downstream d3-deoxySL metabolites, while induction of these enzymes increases their levels. Cells were treated with d3-deoxySA (1 μM) and either the inhibitor HET0016 (5 μM) or ATRA (20 μM) for 24 h, after which the d3-deoxySLs were extracted and quantified by LC/MS. A: While the differences in d3-deoxySA and d3-deoxySO were not significant between controls and HET0016 treatment, the downstream d3-deoxySL metabolites were significantly decreased in the presence of the inhibitor. B: The d3-deoxySA was significantly lower in the ATRA-treated cells, while the downstream metabolites were all significantly and drastically increased. Statistical significance of the differences between untreated and treated cells was calculated using the Student’s t-test. Bars represent averages ± SEM. *P < 0.05, **P < 0.01; n.s., not significant. See also supplemental Figs. S3, S4.