title: Reversal of P-glycoprotein-mediated MDR by 5,7,3',4',5'-pentamethoxyflavone and SAR.
abstract: During screening for the flavonoid chemosensitizers, it was found that 5,7,3',4',5'-pentamethoxyflavone (PMF) was equipotent to verapamil in vitro with respect to the chemosensitizing effect. PMF appears to have a chemosensitizing effect not only by increasing the intracellular accumulation of the drugs without competition in a binding site of azidopine but also by interfering with the substrate-stimulated ATPase activity. Structure-activity relationship suggests that methoxylated substitution and its numbers or sites of the rings are more important than its hydroxylated counterparts in chemosensitization. Overall, PMF is anticipated to be a novel and highly potent second-generation flavonoid chemosensitizer because PMF has significant advantages of having a high therapeutic index, of being a non-transportable inhibitor, and of having a low possibility of drug interactions at the azidopine-binding site of Pgp.
authors.affiliation: Research Center for Resistant Cells, Chosun University, Gwangju 501-759, Republic of Korea. chchoi@chosun.ac.kr
authors.forename: Cheol-Hee
authors.initials: CH
authors.lastname: Choi
authors.forename: Joon-Ho
authors.initials: JH
authors.lastname: Kim
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Kim
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003630:Daunorubicin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology*; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism* / Q000473:pathology*; D013329:Structure-Activity Relationship; D014750:Vincristine / Q000494:pharmacology*
chemical_list: C488726:5,7,3',4',5'-pentamethoxyflavone; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D005419:Flavonoids; D014750:Vincristine; D000251:Adenosine Triphosphatases; D003630:Daunorubicin