Linked Life Data

9130140

Source:http://linkedlifedata.com/resource/pubmed/id/9130140

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1997-7-24
pubmed:abstractText
Among the ion channels and pumps activated by growth factor stimulation, K+ channels have been implicated in the growth and proliferation of several cancer cell lines. The role of these channels in central nervous system tumors, however, has not been described. This study used the malignant astrocytoma cell lines U87 and A172. 4-Aminopyridine (4-AP) inhibition of proliferation was dose dependent, and assessment using a TUNEL in situ assay revealed that apoptosis occurred in U87 cells with wild-type p53 but not in A172 cells with mutant p53 (24-hr incubation with mM 4-AP). In patch clamp experiments, we identified two types of K+ currents in both cell lines, a charybdotoxin-sensitive Ca2(+)-activated K+ channel and a 4-AP-sensitive outward rectifier K+ current. The outward rectifier current was blocked by 4-AP in a dose-dependent manner, with half-maximal block occurring at 3.9 mM. The blocking effect of 4 mM 4-AP was noticeable at potentials as low as -65 mV and was statistically significant at -60 mV and above, suggesting that 4-AP-sensitive current is active at physiological potentials. By contrast, charybdotoxin (1 microM) and tetraethylammonium. Cl (2 mM) blocked the Ca2(+)-activated K+ channel in both cell lines but had no appreciable effect on cell growth. Our findings reveal that 4-AP inhibits proliferation and the outward rectifier K+ channel in both U87 and A172 cells. More studies are needed, however, to describe the mechanism by which K+ channels influence proliferation and induce apoptosis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0360-4012
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
48
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
122-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
4-Aminopyridine causes apoptosis and blocks an outward rectifier K+ channel in malignant astrocytoma cell lines.
pubmed:affiliation
Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't