Figure 4. Fenretinide induces ROS in alveolar rhabdomyosarcoma cell lines.

A) Rh4 and RMS13 cells were treated for 24 hours with an IC₅₀ concentration of fenretinide. H2-DCF-DA was added thereafter for 1 hour. Hydrogen peroxide was added to a final concentration of 250 µM to enhance ROS generation. Final concentration of TPA was 1 µM. Fluorescence was analyzed at 530 nm. The means ± standard deviations (error bars) of three experiments are hown. Columns, mean; bars, s.d. *** p<0,001 compared to wt. B) The effect induced by fenretinide could be blocked by a ROS inhibitor, L-ascorbic acid. Western blot analysis of Rh4 and RMS13 cells treated with IC₅₀ fenretinide alone or a combination of IC₅₀ fenretinide plus 100 µM L-ascorbic acid during different time-points (24–48–72 hours). Cells treated with IC₅₀ fenretinide plus L-ascorbic acid did not show reduction in PAX3/FOXO1 levels.