Allosteric inhibitors of telomerase: oligonucleotide N3'-->P5' phosphoramidates.
Telomerase is a ribonucleoprotein responsible for maintaining telomeres in nearly all eukaryotic cells. The enzyme is able to utilize a short segment of its RNA subunit as the template for the reverse transcription of d(TTAGGG) repeats onto the ends of human chromosomes. Transfection with telomerase was shown to confer immortality on several types of human cells. Moreover, telomerase activation appears to be one of the key events required for malignant transformation of normal cells. Inhibition of telomerase activity in transformed cells results in the cessation of cell proliferation in cultures and provides the rationale for the selection of telomerase as a target for anticancer therapy. Using oligonucleotide N3'-->P5' phosphoramidates (NPs) we have identified a region of the human telomerase RNA subunit (hTR) approximately 100 nt downstream from the template region whose structural integrity appears crucial for telomerase enzymatic activity. The oligonucleotides targeted to this segment of hTR are potent and specific inhibitors of telomerase activity in biochemical assays. Mutant telomerase, in which 3 nt of hTR were not complementary to a 15 nt NP, was found to be refractory to inhibition by that oligonucleotide. We also demonstrated that the binding of NP, oligonucleotides to this hTR allosteric site results in a marked decrease in the affinity of a telomerase substrate (single-stranded DNA primer) for the enzyme.
Pruzan
Ronald
R
Geron Corporation, 230 Constitution Drive, Menlo Park, CA 94025, USA. rpruzan@geron.com
Pongracz
Krisztina
K
Gietzen
Kimberly
K
Wallweber
Gerald
G
Gryaznov
Sergei
S
D000494:Allosteric Regulation; D000495:Allosteric Site; D000577:Amides / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D006801:Humans; D020128:Inhibitory Concentration 50; D007700:Kinetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000378:metabolism; D010756:Phosphoric Acids / Q000378:metabolism*; D012313:RNA / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D019098:Telomerase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013698:Templates, Genetic; D013816:Thermodynamics
D000577:Amides; D017931:DNA Primers; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense; D010756:Phosphoric Acids; D011994:Recombinant Proteins; C422952:telomerase RNA; D012313:RNA; C011067:phosphoramidic acid; D019098:Telomerase