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PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
2009-12-1
pubmed:abstractText
The ATP-binding cassette (ABC)-transporter P-glycoprotein (Pgp, also known as ABCB1) is the best characterized factor involved in multidrug resistance (MDR) of cancer cells. Pgp, which is encoded by the MDR1 gene, acts as a membrane-embedded drug extrusion pump for multiple structurally unrelated cytotoxic drugs. Inhibition of the pump activity of Pgp by low-molecular weight pharmacologically active compounds as a method to reverse MDR in cancer patients has been studied extensively, but so far clinical trials have generally been disappointing. Thus, experimental strategies for overcoming MDR are under investigation. These approaches include the application of the RNA interference (RNAi) technology. RNAi is a physiological mechanism triggered by small double-stranded RNA molecules resulting in a sequence-specific gene-silencing. Besides its potential for development of novel therapeutics, RNAi also offers the possibility for specific inhibition of cellular targets in functional investigations. For specific inhibition of Pgp by triggering the RNAi pathway, transient gene-silencing by application of small interfering RNA (siRNA), and stable inhibition by transfection of MDR cancer cells with short hairpin RNA (shRNA) encoding expression cassettes encoded on plasmid DNA are described. Efficacy of RNAi on MDR1 mRNA expression level is determined by quantitative real-time RT-PCR and Northern blot. The consequences of RNAi on protein expression level are measured by Western blot and immunohistochemistry. The effects on the drug extrusion activity are measured by a drug accumulation assay based on flow cytometry, and reversal of the drug-resistant phenotype by assessment of drug-specific IC(50)-values by a cell proliferation assay based on colorimetry.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1940-6029
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
596
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
447-65
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Overcoming multidrug resistance by RNA interference.
pubmed:affiliation
Charité Campus Mitte, Institute of Pathology, Berlin, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't