Linked Life Data

14567677

Source:http://linkedlifedata.com/resource/pubmed/id/14567677

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
42
pubmed:dateCreated
2003-10-21
pubmed:abstractText
Selection of tumor cell lines with anticancer drugs has led to the appearance of multidrug-resistant (MDR) subclones with P-glycoprotein 1 (P-gp1) expression. These cells are cross-resistant to several structurally and functionally dissimilar drugs. Interestingly, in the process of gaining resistance, MDR cells become hypersensitive or collaterally sensitive to membrane-active agents, such as calcium channel blockers, steroids, and local anaesthetics. In this report, hypersensitivity to the calcium channel blocker, verapamil, was analyzed in sensitive and resistant CHO cell lines. Our results show that treatment with verapamil preferentially induced apoptosis in MDR cells compared to drug-sensitive cells. This effect was independent of p53 activity and could be inhibited by overexpression of the Bcl-2 gene. The induction of apoptosis by verapamil had a biphasic trend in which maximum cell death occurred at 10 microM, followed by improved cell survival at higher concentrations (50 microM). We correlated this effect to a similar biphasic trend in P-gp1 ATPase activation by verapamil in which low concentrations of verapamil (10 microM) activated ATPase, followed by inhibition at higher concentrations. To confirm the relationship between apoptosis and ATPase activity, we used two inhibitors of P-gp1 ATPase, PSC 833 and ivermectin. These ATPase inhibitors reduced hypersensitivity to verapamil in MDR cells. In addition, low concentrations of verapamil resulted in the production of reactive oxygen species (ROS) in MDR cells. Taken together, these results show that apoptosis was preferentially induced by P-gp1 expressing cells exposed to verapamil, an effect that was mediated by ROS, produced in response the high ATP demand by P-gp1.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12163-73
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
A mechanism for P-glycoprotein-mediated apoptosis as revealed by verapamil hypersensitivity.
pubmed:affiliation
Institute of Parasitology, McGill University, Macdonald Campus, Ste-Anne de Bellevue, Quebec H9X 3V9, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't