Figure 1.

Inhibition of AHR enhances UVB-induced apoptosis in human KC. (a) Real-time PCR analyses revealed a reduced AhR mRNA expression in NCTC-shAHR KC compared with NCTC-EV and NCTC 2544 cells. AHR transcripts are shown as fold of NCTC 2544. *Significantly reduced compared with NCTC 2544; (b) NCTC 2544, NCTC-EV, and NCTC-shAHR KC were irradiated with 200 J/m² UVB. After 6 h, KC were harvested and CYP1A1, COX-2, and PAI-2 mRNA were quantified by real-time PCR. Expression rates are given as fold of non-irradiated control. *Significantly reduced compared with NCTC-EV; (c) NCTC-EV and NCTC-shAHR KC were irradiated with 200 or 400 J/m² UVB. After 24 h, percentage of sub-G1 DNA content was measured by PI staining and flow cytometry. *Significantly increased compared with NCTC-EV, †significantly increased compared with sham-irradiated NCTC-EV; (d) NCTC-EV and NCTC-shAHR KC were irradiated with 200 or 400 J/m² UVB. After 24 h, protein was isolated and western blots were done using an anti-PARP-1 antibody that detects both PARP-1 and cleaved (cl.) PARP-1. *Significantly increased compared with NCTC-EV exposed to 400 J/m² UVB; (e) NCTC-EV and NCTC-shAHR KC were treated with 0.1% DMSO or 20 μM MNF 1 h prior exposure to 400 J/m² UVB, and 24 h later the percentage of sub-G1 DNA content was measured. *Significantly increased compared with DMSO-treated NCTC-EV, †significantly increased to sham-irradiated solvent control cells. (f) NCTC 2544 and NCTC-EV KC were treated with 0.1% DMSO or 20 μM MNF 1 h prior exposure to 400 J/m² UVB, and 24 h later cleavage of caspase-3 was analyzed. *Significantly increased compared with DMSO-treated NCTC 2544 and NCTC-EV cells, respectively