Prolonged induction of @entity994 / XXXX / @entity15308 / @entity1364 complex by epidermal growth factor receptor activation mediates ligand-induced A431 cell growth inhibition.

@entity1 @entity1364 @entity71847 @entity5 @entity957 @entity15308 @entity4179 @entity1167 @entity20830 @entity669 @entity994
Proliferation of some cultured @entity1 @entity5 cell lines bearing high numbers of @entity4179 ( @entity4179 ) receptors is paradoxically inhibited by @entity4179 in nanomolar concentrations. In the present study, we have investigated the biochemical mechanism of growth inhibition in A431 @entity1 @entity957 cells exposed to exogenous @entity4179 . In parallel, we studied a selected subpopulation, @entity71847 , which is resistant to @entity4179 -mediated growth inhibition. We observed a marked reduction in @entity15308 ( @entity15308 ) activity when A431 and A431-F cells were cultured with 20 nM @entity4179 for 4 h. After further continuous exposure of A431 cells to @entity4179 , the @entity15308 activity remained at a low level and was accompanied by persistent @entity1167 . In contrast, the early reduced @entity15308 activity and G1 accumulation in A431-F cells was only transient. We found that, at early time points (4-8 h), @entity4179 induces @entity994 / @entity994 mRNA and protein expression in both @entity4179 -sensitive A431 cells and @entity4179 -resistant A431-F cells. But only in A431 cells, was @entity994 / @entity994 expression sustained at a significantly increased level for up to 5 d after addition of @entity4179 . Induction of @entity994 / @entity994 by @entity4179 could be inhibited by a specific @entity4179 receptor @entity669 kinase inhibitor, @entity20830 , suggesting that @entity994 / @entity994 induction was a consequence of receptor @entity669 kinase activation by @entity4179 . We also demonstrated that the increased @entity994 / @entity994 was associated with both @entity15308 and @entity1364 ( @entity1364 ). Taken together, our results demonstrate that @entity994 / @entity994 is an important mediator of @entity4179 -induced @entity1167 and growth inhibition in A431 cells.
