title: [Reversal of multidrug resistance of tumor cells by anti-mdr1 ribozyme].
abstract: OBJECTIVE
  To stably reverse the multidrug resistance (MDR) of breast carcinoma cells in vitro.
  
  
  METHODS
  Two anti-mdr-1 ribozyme plasmids, RZ196 and RZ179, were constructed with EGFP as reporter gene and transfected into drug-resistant breast carcinoma cells in vitro. The expression of EGFP was observed by laser confocal microscopy. Flow cytometry, RT-PCR and Rhodamine123 efflux assay were used to detect P-glyco protein (p-gp) and mdr-1 mRNA.
  
  
  RESULTS
  After transfection with RZ196 and RZ179, the mdr-1 indices were reduced from 2.20 to 0.76 and 1.40, the expression rates of p-gp were reduced from 55.0% to 4.6% and 18.2%, the fluorescence intensity increased from 22.0% to 46.2% and 70.1%, TCL reduced from 75% to 28% and 43% respectively. In addition, the expression of ribozyme plasmid in tumor cells was stable under G418 selection. After two months, the mdr-1 indices remained at 0.81 and 1.47 in the cells transfected RZ196 and RZ179 respectively. The expression rates of p-gp were 5.2% and 19.5% and the Rh123 fluorescence intensity was 51.4% and 71.6% respectively.
  
  
  CONCLUSIONS
  Both anti-mdr-1 ribozyme RZ196 and RZ179 can stably reverse MDR phenotype of breast carcinoma cells in vitro. RZ196 construct appears to be more effective.
authors.affiliation: Department of Pathology, School of Medicine, University of Shandong, Jinan 250012, China. gpzmq@sina.com
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.forename: Geng-Yin
authors.initials: GY
authors.lastname: Zhou
authors.forename: Qing-Hui
authors.initials: QH
authors.lastname: Zhang
authors.forename: Cheng-Jun
authors.initials: CJ
authors.lastname: Zhou
authors.forename: Jun-Hui
authors.initials: JH
authors.lastname: Zhen
authors.forename: Yan-Lin
authors.initials: YL
authors.lastname: Sun
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000628:therapy; D004317:Doxorubicin / Q000494:pharmacology; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D018014:Gene Transfer Techniques; D019450:Genes, MDR / Q000235:genetics; D005822:Genetic Vectors; D006801:Humans; D016337:RNA, Catalytic / Q000235:genetics*; D012190:Retroviridae / Q000235:genetics
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D016337:RNA, Catalytic; C427204:hammerhead ribozyme; D004317:Doxorubicin