The multidrug resistance-associated protein (MRP), mediating a multidrug resistance (MDR) phenotype, has been reported to be overexpressed in several drug-selected lung cancer cell lines.
To this end, we took advantage of the fact that the overexpression of MDR1 and MRP genes, two genes known to be associated with the development of drug resistance, is very common in lung cancer.
In conclusion, we have shown that a human revertant lung cancer cell line (COR-L23/Rev) has the ability to recover quickly, similar levels of MRP expression and resistance as COR-L23/R after a transient exposure to the MDR-drugs doxorubicin and vincristine.
Expression of gamma-glutamylcysteine synthetase (gamma-GCS) and multidrug resistance-associated protein (MRP), but not human canalicular multispecific organic anion transporter (cMOAT), genes correlates with exposure of human lung cancers to platinum drugs.
In most lung cancers, this resistance is associated with the overexpression of (a) multidrug resistance-associated protein (MRP) responsible for drug efflux from the cancer cells (pump resistance) and (b) BCL2 protein that activates antiapoptotic cellular defense (nonpump resistance).
Using an RNase protection assay we have analyzed the expression of MRP in non-Pgp MDR sublines of the human lung cancer cell lines SW-1573 (non-small cell lung cancer) and GLC4 (small cell lung cancer).
Multidrug resistance-associated protein (MRP) mRNA expression and drug sensitivity in lung cancer cells were examined, and the effects of verapamil, a modulating agent for MRP, on drug sensitivity were also tested.