title: Modulation of the atypical multidrug-resistant phenotype by a hammerhead ribozyme directed against the ABC transporter BCRP/MXR/ABCG2.
abstract: The phenomenon of multidrug resistance (MDR) in human cancers is one of the major causes of failure of chemotherapy. A recently identified new member of the superfamily of ATP-binding cassette transporters, breast cancer resistance protein (BCRP), was demonstrated to confer an atypical multidrug-resistant phenotype to tumor cells. To overcome the BCRP-mediated drug resistance, a specific anti-BCRP hammerhead ribozyme was introduced into the human gastric carcinoma cell line, EPG85-257RNOV, exhibiting an atypical MDR phenotype. By this approach, the expression levels of the targeted BCRP-encoding mRNA and the BCRP transport protein were decreased to the low constitutive expression level that was observed in highly drug-sensitive parental gastric carcinoma cells. In addition, in the anti-BCRP ribozyme-treated cells, the cellular drug accumulation was dramatically increased to the level measured in drug-sensitive cells. These effects were accompanied by an extensive reversal of the drug-resistant phenotype of more than 80%. Because additional mechanisms contribute to the multimodal-mediated MDR phenotype exhibited by this gastric carcinoma cell line, the data suggest that the BCRP-mediated contingent to the drug resistance was overcome nearly completely. Moreover, the data indicate that ribozyme-based gene therapy may be clinically applicable in preventing and reversing BCRP-mediated atypical MDR.
authors.affiliation: Institute of Pathology, Charité Campus Mitte, Humboldt University Berlin, D-10117 Berlin, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Kowalski
authors.forename: Ulrike
authors.initials: U
authors.lastname: Stein
authors.forename: George L
authors.initials: GL
authors.lastname: Scheffer
authors.forename: Hermann
authors.initials: H
authors.lastname: Lage
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism*; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D001483:Base Sequence; D002455:Cell Division; D002470:Cell Survival; D002474:Cell-Free System; D002945:Cisplatin / Q000494:pharmacology; D003630:Daunorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D005047:Etoposide / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D008942:Mitoxantrone / Q000494:pharmacology; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D010455:Peptides / Q000494:pharmacology; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D016337:RNA, Catalytic / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000188:drug therapy; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000903:Antibiotics, Antineoplastic; D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; D009363:Neoplasm Proteins; D010455:Peptides; D016337:RNA, Catalytic; D012333:RNA, Messenger; C427204:hammerhead ribozyme; D005047:Etoposide; D008942:Mitoxantrone; D002945:Cisplatin; D003630:Daunorubicin