title: Restoration of chemosensitivity in cancer cells with MDR phenotype by deoxyribozyme, compared with ribozyme.
abstract: One of the main mechanisms for multidrug resistance (MDR) involves multidrug resistance gene 1 (MDR1) which encodes P-glycoprotein (Pgp). Pgp acts as a drug efflux pump and exports chemotherapeutic agents from cancer cells. Specific inhibition of Pgp expression by gene therapy is considered a well-respective strategy having less innate toxicities. At present, the investigation of DRz in reversal MDR is scarce. In the study, phosphorothioate DRz that targets to the translation initiation codon AUG was synthesized and transfected into breast cancer cells and leukemia cells with MDR phenotype. ASODN (antisense oligonucleotide) and ribozyme targets to the same region were also synthesized for comparison analysis. Alterations in MDR1 mRNA and Pgp were determined by RT-PCR, Northern blot, flow cytometry and Rh123 retention tests. Chemosensitivity of the treated cells was determined by MTT assay. The results showed that DRz could significantly suppress expression of MDR1 mRNA and inhibit synthesis of Pgp. The efflux activity of Pgp was inhibited accordingly. Chemosensitivity assay showed that a 21-fold reduction in drug resistance for Adriamycin and a 45-fold reduction in drug resistance for Vinblastine were found in the treated cells 36h after transfection. These data suggest that DRz targeted to the translation initiation codon AUG can reverse MDR phenotype in cancer cells and restore their chemosensitivity. Moreover, the reversal efficiency of DRz is better than that of ribozyme and ASODN targets to the same region of MDR1 mRNA.
authors.affiliation: Department of Pathology, School of Medicine, Shandong University, Jinan 250012, China.
authors.forename: Ai-Yan
authors.initials: AY
authors.lastname: Xing
authors.forename: Duan-bo
authors.initials: DB
authors.lastname: Shi
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.forename: Yan-Lin
authors.initials: YL
authors.lastname: Sun
authors.forename: Xiao
authors.initials: X
authors.lastname: Wang
authors.forename: Jian-ping
authors.initials: JP
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000235:genetics* / Q000628:therapy; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics; D021881:DNA, Catalytic / Q000235:genetics* / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007938:Leukemia / Q000235:genetics* / Q000628:therapy; D016376:Oligonucleotides, Antisense / Q000235:genetics; D054735:Phosphorothioate Oligonucleotides; D014162:Transfection; D014747:Vinblastine / Q000494:pharmacology
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D021881:DNA, Catalytic; D016376:Oligonucleotides, Antisense; D054735:Phosphorothioate Oligonucleotides; D014747:Vinblastine; D004317:Doxorubicin