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Zinc
induces apoptosis that can be suppressed by lanthanum in C6 rat glioma cells
Haase H, Watjen W,
Beyersmann D
Fachbereich Biologie/Chemie, Universitat Bremen, Germany
Zinc ions have both
essential and toxic effects on mammalian cells.
Here we report the ability of
zinc to act as an inducer of apoptosis in C6 rat glioma cells.
Incubation with
150 to 300 microM ZnCl2 caused cell death that was characterized as apoptotic by
internucleosomal DNA fragmentation, formation of apoptotic bodies, nuclear
fragmentation and breakdown of the mitochondrial membrane potential.
On the
other hand, zinc deprivation by the membrane permeable chelator TPEN
[N,N,N',N',-tetrakis (2-pyridyl-methyl)-ethylenediamine] also induced programmed
death in this cell line, indicating the existence of intracellular zinc levels
below and above which apoptosis is induced.
Zinc-induced apoptosis in C6 cells
was independent of major signaling pathways (protein kinase C, mitogen activated
protein kinase and guanylate cyclase) and protein synthesis, but was increased
by facilitating zinc uptake with the ionophore pyrithione.
Lanthanum(III)chloride was also able to increase the net zinc uptake, but
nevertheless apoptotic features and zinc toxicity were reduced.
Remarkably,
lanthanum suppressed the zinc-induced breakdown of the mitochondrial membrane
potential.
We conclude that in C6 cells lanthanum acts in two different ways, as
a promoter of net zinc uptake and as a suppressor of zinc-induced apoptosis.
PMID: 11592404 [PubMed - indexed for MEDLINE]
Source: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11592404&dopt=Abstract
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