T. Borchardt et al., Differential effects of zinc on amyloid precursor protein (APP) processingin copper-resistant variants of cultured Chinese hamster ovary cells, CELL MOL B, 46(4), 2000, pp. 785-795
Previous studies have demonstrated that adding copper to Chinese-hamster ov
ary (CHO) cells greatly reduced the levels of beta-amyloid (A beta) peptide
in parental CHO-K1 and in copper resistant CHO-CUR3 cells which have lower
intracellular copper levels. In the current study, zinc, the zinc chelator
1,10-phenanthroline or copper chelators bathocuproine and D-penicillamine
were added to the culture media of stably transfected CHO cells. The data s
how that zinc up to concentrations of 50 mu M or the presence of 1,10-phena
nthroline specifically increased the level of secreted APP in CHO-K1 cells.
By contrast, the level of secreted APP in CHO-CUR3 cells remained unaffect
ed. APP holoprotein increased dramatically in CHO-CUR3 cells compared with
CHO-K1 cells. The large decrease of A beta release seen in both cell lines
at elevated extracellular zinc levels was due to specific inhibition of sec
retion. These results indicate that a disturbed zinc-homeostasis may be an
important factor influencing APP production, transport and processing.