Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.6.3.44 (
P-glycoprotein
)
13,344
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Intrinsic or acquired resistance of tumor cells to multiple cytotoxic drugs (multidrug resistance MDR) is a major cause of failure of cancer chemotherapy. MDR is often caused by elevated expression of drug transporters such as
P-glycoprotein
(
P-gp
) or multidrug resistance protein (MRP). A number of compounds, termed chemosensitizers, have little or no cytotoxic action of their own, but inhibit (
P-gp
) or MRP-mediated drug export and are capable of sensitizing MDR cells to the cytotoxic effects of chemotherapeutic drugs. Here we examined the ability of steroidal alkaloids of plant origin, namely the Veratrum sp. alkaloid cyclopamine and the Lycopersicon sp. alkaloid tomatidine, to act as potent and effective chemosensitizers in multidrug resistant tumor cells. Drug uptake was determined by measuring accumulation of tetramethylrosamine in multidrug resistant NCI AdrR human adenocarcinoma cells. Resistance to adriamycin and vinblastine was determined by utilizing the MTT cell survival assay.
Cyclopamine
and tomatidine elevate tetramethylrosamine uptake by NCI AdrR cells and sensitize the cells to the cytotoxic action of adriamycin and vinblastine. In both cases these agents are comparable in patency and efficacy to verapamil, a reversal agent commonly used in MDR research. It is concluded that steroidal alkaloids of plant origin act as inhibitors of
P-gp
-mediated drug transport and multidrug resistance and therefore may serve as chemosensitizers in combination chemotherapy with conventional cytotoxic drugs for treating multidrug resistant cancer.
...
PMID:Inhibitory effect of steroidal alkaloids on drug transport and multidrug resistance in human cancer cells. 1139 62
