Inh I or Inh II suppresses UVB-induced AP-1 activity in a
concentration-dependent manner. Stably transfected JB6
P+1-1 AP-1 luciferase reporter cells were cultured and
starved as indicated in the text. After a 30-min treatment of the cells
with Inh I or Inh II at the concentrations indicated, the cells were or
were not exposed to UVB irradiation (4 kJ/m2) and
cultured for another 12 h before harvest and determination of AP-1
activity. AP-1 activity is expressed as relative luciferase units as
assessed by a luminometer. (A) Inh I or Inh II treatment
resulted in slight, but insignificant (P > 0.05;
mean ± SD of triplicate experiments, six wells each), increase of
basal AP-1 activity. (B) UVB stimulation alone induced a
13.8- to 14.3-fold increase in AP-1 activity. Inh I (40–80 μM) or
Inh II (20–80 μM) significantly inhibited AP-1 activity in response
to UVB. ∗, P < 0.05; mean ± SD for
triplicate experiments, six wells each.