The binding of the transcription factor AP-1 to DNA has been shown to
be modulated by redox control mechanisms, Selenite and selenodiglutath
ione (GS-Se-SG), inhibit mammalian cell growth and are efficient oxida
nts of reduced thioredoxin and reduced thioredoxin reductase, Here, we
report that selenite and GS-Se-SG efficiently inhibited AP-1 DNA-bind
ing in nuclear extracts from 3B6 lymphocytes, A GS-Se-SG concentration
of 0.75 mu M resulted in 50% inhibition of AP-1 DNA-binding, whereas
the same effect was achieved with 7.5 mu M selenite, Nuclear extracts
prepared from human 3B6 lymphocytes exposed for 4 h to 10 mu M selenit
e showed a 50% reduction of AP-1 binding, These data suggest that sele
nite and selenodiglutathione inactivate the AP-1 factor and provide a
mechanism by which selenium compounds inhibit cell growth.