• Title, Summary, Keyword: DNAzymes

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Efficient Target Site Selection for an RNA-cleaving DNAzyme through Combinatorial Library Screening

  • Kim, Ki-Sun;Choi, Woo-Hyung;Gong, Soo-Jeong;Oh, Sang-taek;Kim, Jae-Hyun;Kim, Dong-Eun
    • Bulletin of the Korean Chemical Society
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    • v.27 no.5
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    • pp.657-662
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    • 2006
  • Identification of accessible sites in targeted RNAs is a major limitation to the effectiveness of antisense oligonucleotides. A class of antisense oligodeoxynucleotides, known as the “10-23” DNA enzyme or DNAzyme, which is a small catalytic DNA, has been shown to efficiently cleave target RNA at purine-pyrimidine junctions in vitro. We have designed a strategy to identify accessible cleavage sites in the target RNA, which is hepatitis C virus nonstructural gene 3 (HCV NS3) RNA that encodes viral helicase and protease, from a pool of random DNAzyme library. A pool of DNAzymes of 58 nucleotides-length that possess randomized annealing arms, catalytic core sequence, and fixed 5'/3'-end flanking sequences was designed and screened for their ability to cleave the target RNA. The screening procedure, which includes binding of DNAzyme pool to the target RNA under inactive condition, selection and amplification of active DNAzymes, incubation of the selected DNAzymes with the target RNA, and target site identification on sequencing gels, identified 16 potential cleavage sites in the target RNA. Corresponding DNAzymes were constructed for the selected target sites and were tested for RNA-cleavage in terms of kinetics and accessibility. These selected DNAzymes were effective in cleaving the target RNA in the presence of $Mg^{2+}$. This strategy can be applicable to identify accessible sites in any target RNA for antisense oligonucleotides-based gene inactivation methods.

AKT1 Inhibitory DNAzymes Inhibit Cell Proliferation and Migration of Thyroid Cancer Cells

  • Yang, Le;He, Jin-Ting;Guan, Hong;Sun, Ya-Dong
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.4
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    • pp.2571-2575
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    • 2013
  • AKT1 is a member of the serine/threoine AGC protein kinase family involved in thyroid cancer metabolism, growth, proliferation and survival. It is overexpressed in thyroid tumors. In this study, we designed two AKT1 specific DNAzymes (DRz1 and DRz2) that target AKT1 mRNA. The results showed that DRz1 could decrease the expression of AKT1 by 58%. Furthermore, DRz1 significantly inhibited cell proliferation, induced apoptosis and inhibited invasion in SW597 cells. In addition, down-regulation of survivin expression was associated with decreased caspase-3, VEGF and MMP2 in SW597 cells after 24 h. In our study, the efficacy of DRz1 in decreasing AKT1 protein levels were better than DRz2. AKT1-DRz1 might have anti-tumorigenic activity and may provide the basis for a novel therapeutic intervention in thyroid cancer treatment.

Ani-survivin DNAzymes Inhibit Cell Proliferation and Migration in Breast Cancer Cell Line MCF-7

  • Zhang, Min;Sun, Yi-Fu;Luo, Su
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.12
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    • pp.6233-6237
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    • 2012
  • Survivin, a new member of the inhibitor of apoptosis protein (IAP) family, both inhibits apoptosis and regulates the cell cycle. It is overexpressed in breast tumor tissues. In this study, we designed two survivin specific DNAzymes (DRz1 and DRz2) targeting survivin mRNA. The results showed that DRz1 could decrease the expression of survivin by nearly 60%. Furthermore, DRz1 significantly inhibited cell proliferation, induced apoptosis and inhibited migration in MCF-7 cells. In addition, down-regulation of survivin expression was associated with increased caspase-3 and -9 activities in MCF-7 cells after 24 h transfection. In our experiments, the efficacy of DRz1 to influence survivin levels and associated effects were better than DRz2. Survivin-DRz1 might have anti-tumorigenic activity and may potentially provide the basis for a novel therapeutic intervention in breast cancer treatment.