title: Modulation of P-glycoprotein function and reversal of multidrug resistance by (-)-epigallocatechin gallate in human cancer cells.
abstract: Multidrug resistance (MDR) is a major obstacle in the chemotherapeutic treatment of many human cancers. In this study, the reversal of P-glycoprotein (P-gp) mediated multidrug resistance by (-)-epigallocatechin gallate (EGCG) and its molecular mechanism were investigated. A three-dimensional model of carboxyl-terminal nucleotide binding domain (NBD2) from P-gp was built by homology modeling. The structural model of the complex indicates that EGCG was tightly bound to the ATP-binding site of NBD2. EGCG modulated the function of P-gp and increased the intracellular accumulation of chemotherapeutic agent doxorubicin (DOX) in drug-resistant KB-A1 cells. When KB-A1 cells were exposed to 10 microg/ml DOX combined with 10, 30, 50 microM EGCG for 4 h, the intracellular concentrations of DOX were increased 1.5, 1.9, 2.3 times, respectively compared with DOX alone treatment. In vitro EGCG potentiated the cytotoxicity of DOX to drug-resistant KB-A1 cells. In KB-A1 cell xenograft model, EGCG could also enhance the efficacy of DOX and increased the DOX concentration in the resistant tumors. Thus, these results suggest that EGCG modulated the function of P-gp and reversed P-gp mediated multidrug resistance in human cancer cells.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai 200237, PR China.
authors.forename: Feng
authors.initials: F
authors.lastname: Qian
authors.forename: Dongzhi
authors.initials: D
authors.lastname: Wei
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Shengli
authors.initials: S
authors.lastname: Yang
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000187:drug effects* / Q000502:physiology; D002392:Catechin / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D006801:Humans; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002392:Catechin; C045651:epigallocatechin gallate