title: In vivo reversibility of multidrug resistance by the MDR-modulator dexniguldipine (niguldipine derivative B859-35) and by verapamil.
abstract: The newly synthesized dihydropyridine derivative B859-35 was previously shown in vitro to be highly effective in reversing multidrug resistance (MDR) of P-glycoprotein positive tumor cell lines, such as the adriamycin (ADR) resistant erythroleukemia F4-6RADR cells. In the current study B859-35 was investigated for its efficiency in reversing MDR in an in vivo tumor model for preclinical testing of MDR-modulators. F4-6RADR cells were injected into the right flank of nude mice while the parent cells were injected into the left flank. The animals were treated i.p. with ADR (9.0 mg/kg body weight) combined with B859-35 (5, 10, or 25 mg/kg) or, for comparison and validation, with verapamil (VRP) (75 mg/kg). The effects of ADR and the MDR-modulator combination were evaluated by histological morphometry of the tumors. While ADR alone was shown to be ineffective in resistant cells, the combinations of ADR + B859-35 as well as of ADR + VRP were highly active in reducing the number of viable cells in the resistant tumor nodule by 67 +/- 9% or by 53 +/- 11% of controls. This model provides evidence that even in vivo, MDR modulators can be effective in reversing drug resistance. In addition, it presents a potentially useful and rapid preclinical system for in vivo studies on the modification of drug resistance.
authors.affiliation: Institute of Pathology, Charité, Humboldt-Universität zu Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Dietel
authors.forename: H
authors.initials: H
authors.lastname: Boss
authors.forename: A
authors.initials: A
authors.lastname: Reymann
authors.forename: S
authors.initials: S
authors.lastname: Pest
authors.forename: A
authors.initials: A
authors.lastname: Seidel
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000633:toxicity; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004095:Dihydropyridines / Q000494:pharmacology* / Q000633:toxicity; D019008:Drug Resistance, Neoplasm / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D014407:Tumor Cells, Cultured; D014700:Verapamil / Q000494:pharmacology*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D014700:Verapamil; C054074:niguldipine