title: Screening of deoxyribozyme with high reversal efficiency against multidrug resistance in breast carcinoma cells.
abstract: Specific inhibition of P-glycoprotein (Pgp) expression, which is encoded by multidrug resistance gene-1 (MDR1), is considered a well-respected strategy to overcome multidrug resistance (MDR). Deoxyribozymes (DRz) are catalytic nucleic acids that could cleave a target RNA in sequence-specific manner. However, it is difficult to select an effective target site for DRz in living cells. In this study, target sites of DRz were screened according to MDR1 mRNA secondary structure by RNA structure analysis software. Twelve target sites on the surface of MDR1 mRNA were selected. Accordingly, 12 DRzs were synthesized and their suppression effect on the MDR phenotype in breast cancer cells was confirmed. The results showed that 4 (DRz 2, 3, 4, 9) of the 12 DRzs could, in a dose-dependent response, significantly suppress MDR1 mRNA expression and restore chemosensitivity in breast cancer cells with MDR phenotype. This was especially true of DRz 3, which targets the 141 site purine-pyrimidine dinucleotide. Compared with antisense oligonucleotide or anti-miR-27a inhibitor, DRz 3 was more efficient in suppressing MDR1 mRNA and Pgp protein expression or inhibiting Pgp function. The chemosensitivity assay also proved DRz 3 to be the best one to reverse the MDR phenotype. The present study suggests that screening targets of DRzs according to MDR1 mRNA secondary structure could be a useful method to obtain workable ones. We provide evidence that DRzs (DRz 2, 3, 4, 9) are highly efficient at reversing the MDR phenotype in breast carcinoma cells and restoring chemosensitivity.
authors.affiliation: Department of Pathology, Shandong University, School of Medicine, Jinan, China. gaopeng@sdu.edu.cn
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.forename: Jun-Min
authors.initials: JM
authors.lastname: Wei
authors.forename: Peng-Yu
authors.initials: PY
authors.lastname: Li
authors.forename: Cui-Juan
authors.initials: CJ
authors.lastname: Zhang
authors.forename: Wen-Cheng
authors.initials: WC
authors.lastname: Jian
authors.forename: Yu-Hua
authors.initials: YH
authors.lastname: Zhang
authors.forename: Ai-Yan
authors.initials: AY
authors.lastname: Xing
authors.forename: Geng-Yin
authors.initials: GY
authors.lastname: Zhou
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors / Q000235:genetics*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics; D002277:Carcinoma / Q000188:drug therapy* / Q000235:genetics; D045744:Cell Line, Tumor; D021881:DNA, Catalytic / Q000138:chemical synthesis* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D018432:Drug Resistance, Multiple / Q000187:drug effects* / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000187:drug effects* / Q000235:genetics; D005260:Female; D006801:Humans; D035683:MicroRNAs / Q000235:genetics; D054735:Phosphorothioate Oligonucleotides / Q000378:metabolism; D012333:RNA, Messenger / Q000737:chemistry / Q000187:drug effects / Q000235:genetics
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D021881:DNA, Catalytic; C531388:MIRN27 microRNA, human; D035683:MicroRNAs; D054735:Phosphorothioate Oligonucleotides; D012333:RNA, Messenger