Linked Life Data

15035640

Source:http://linkedlifedata.com/resource/pubmed/id/15035640

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2004-3-23
pubmed:abstractText
Pluronic block copolymers (triblock copolymers of poly(ethylene oxide) and poly(propylene oxide)) exhibit a chemosensitizing effect on multidrug resistant cell lines. Changes in membrane permeability are hypothesized to be responsible because inhibition of drug transport mediated by both the multidrug-resistance-associated protein and the P-glycoprotein drug efflux system has been observed. To test this hypothesis, we now have studied the ion conductivity mediated by Pluronic L61. Besides a detergent-like action, the copolymer was able to form regular channels and to exhibit carrier activity. Long living ion channels were formed by polymer oligomerization. Aggregate equilibrium was shifted toward L61 monomers and dimers, which operated as mobile carriers. Copolymer-induced membrane permeability for potassium ions (1 M KCl) was less than 10(-8) cm s(-1), whereas the permeability for uncharged doxorubicin molecules (1 mM) was equal to 5 x 10(-4) cm s(-1). The results are consistent with reports about an increased doxorubicin accumulation in cells (Venne, Li, S., Mandeville, R., Kabanov, A., and Alakhov, V. Y. (1996) Cancer Res. 56, 3626-3629). However, the increased permeability contrasts with the polymer-mediated decrease of drug efflux from cells. Preferential polymer binding to membrane proteins may mask the unspecific effect of L61 observed on lipid bilayers.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
43
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3696-703
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Ionophoric activity of pluronic block copolymers.
pubmed:affiliation
Forschungsinstitut für Molekulare Pharmakologie, Campus Berlin-Buch, Robert-Roessle Strasse 10, 13125 Berlin, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't