title: Inhibition of MDR1 gene expression by antimessenger oligonucleotides lowers multiple drug resistance.
abstract: The multiple drug resistance of neoplastic cells is mediated by overexpression of the human MDR1 gene, which encodes the transmembrane efflux pump P-glycoprotein. In both cell lines and human tumors the MDR phenotype closely correlates with MDR1 mRNA and P-glycoprotein levels. Reversion of the MDR phenotype was attempted in human colorectal adenocarcinoma doxorubicin (Dx)-resistant cells (Lo Vo/Dx) by long-term administration of an equimolecular mixture of three unmodified ODNs (18mer) targeted to adjacent binding sites of the MDR1 mRNA and carried by a synthetic cationic lipid (DOTAP). Three different experimental parameters were used to evaluate the antimessenger agent's effectiveness in comparison with a random sequence ODN: the level of cell resistance to Dx; the level of P-glycoprotein (determined by flow cytometry); the level of MDR1 mRNA (determined by quantitative RT-PCR). Experimental data indicate that the level of both the MDR1 mRNA and the P-glycoprotein is reduced by approximately 50% by treatment of Lo Vo/Dx cells with a 10 microM total concentration of the aODN mixture every 24 h for 15 days. In agreement with these findings, sensitivity to Dx of the antimessenger agent-treated Lo Vo/Dx cells was almost doubled in comparison with random sequence ODN-treated controls.
authors.affiliation: Institute of General Pathology, Viale G. B. Morgagni 50, Florence, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Quattrone
authors.forename: L
authors.initials: L
authors.lastname: Papucci
authors.forename: M
authors.initials: M
authors.lastname: Morganti
authors.forename: M
authors.initials: M
authors.lastname: Coronnello
authors.forename: E
authors.initials: E
authors.lastname: Mini
authors.forename: T
authors.initials: T
authors.lastname: Mazzei
authors.forename: F P
authors.initials: FP
authors.lastname: Colonna
authors.forename: A
authors.initials: A
authors.lastname: Garbesi
authors.forename: S
authors.initials: S
authors.lastname: Capaccioli
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis*; D000230:Adenocarcinoma; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D003110:Colonic Neoplasms; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000633:toxicity*; D018432:Drug Resistance, Multiple / Q000235:genetics*; D015870:Gene Expression / Q000187:drug effects*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D004317:Doxorubicin