Figure 4.

Identification of compounds enabling repair of 6-4PP in XP-C cells. XP-C cells were treated with the 16 primary screen candidate hits at three different concentrations (1, 5 & 10 µM) with pre- and post-irradiation treatments. Irradiation was carried out at a dose of 0.05 J/cm². 24 h post UV the cells were fixed and stained with 6-4PP antibodies for the quantification of DNA damage. Fluorescence intensities of individual cells for each condition were quantified and more than 1000 cells per condition were analyzed. Among the 16 hits, only isoconazole and Clemizole hydrochloride enabled a decrease in the amount of DNA damage post UV shown here. Almost 20% repair of 6-4PP DNA damage was recorded for both drugs at a concentration of 5µM which was found to be significant. DNA damage quantification in DMSO treated irradiated cells was used as positive control showing the maximum amount of DNA damage while quantification of 6-4PP in DMSO treated non-irradiated cells was taken as a negative control with the minimum amount of detected damage. *** p < 0.001, freedman non-parametric test with Dunn’s post hoc analysis. Up to 10,000 cells were analyzed per condition with ±SD.