title: Target site search and effective inhibition of leukaemic cell growth by a covalently closed multiple anti-sense oligonucleotide to c-myb.
abstract: Systematic secondary structure simulation of a target mRNA sequence is shown to be effective for locating a good anti-sense target site. Multiple selected anti-sense sequences were placed in a single molecule. The anti-sense oligonucleotide (oligo) was covalently closed to avoid exonuclease activities and was designated CMAS (covalently closed multiple anti-sense)-oligo. CMAS-oligo was found to be stable, largely preserving its structural integrity after 24 h of incubation in the presence of either exonuclease III or serum. When human c-myb mRNA was targeted by the c-myb CMAS-oligo, expression of the gene was completely abolished. Further, tumour cell growth was inhibited by 82+/-3% as determined by an MTT [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay and by 90+/-1% by [(3)H]thymidine incorporation. When a leukaemic cell line K562 was treated with CMAS-oligo, colony formation on soft agarose was also decreased by 93%. In contrast, treatment with a scrambled control oligo did not significantly inhibit leukaemic cell growth. These results suggest that a rational target site search is possible for an anti-sense oligo and that CMAS-oligo can be employed as an effective anti-sense agent with enhanced stability.
authors.affiliation: Institute for Medical Science, Dongsan Medical Center, Keimyung University, Dongsandong 194, Chunggu, Taegu 700-310, Korea.
authors.forename: I J
authors.initials: IJ
authors.lastname: Moon
authors.forename: Y
authors.initials: Y
authors.lastname: Lee
authors.forename: C S
authors.initials: CS
authors.lastname: Kwak
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: K
authors.initials: K
authors.lastname: Choi
authors.forename: A D
authors.initials: AD
authors.lastname: Schreiber
authors.forename: J G
authors.initials: JG
authors.lastname: Park
mesh_terms: D002455:Cell Division / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics*; D018390:Gene Targeting; D020570:Genes, myb; D006801:Humans; D007938:Leukemia / Q000235:genetics* / Q000473:pathology*; D016376:Oligonucleotides, Antisense / Q000235:genetics* / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger