Cited by 541Telomeres, Telomerase, and SenescenceDNA and Nucleic Acid ChemistryRNA Interference and Gene Delivery

The DOI matches its Crossref record; 47 of the 48 references it cites were found in a registry or an index; none of the 49 sources its claims cite is checked for support yet.

Inhibition of human telomerase in immortal human cells leads to progressive telomere shortening and cell death

Open access
Herbert, B.-S., Pitts, A. E., Baker, S. I., Hamilton, S. E., Wright, W. E., Shay, J. W., Corey, D. R.·1999·Proceedings of the National Academy of Sciences

Abstract

The correlation between telomerase activity and human tumors has led to the hypothesis that tumor growth requires reactivation of telomerase and that telomerase inhibitors represent a class of chemotherapeutic agents. Herein, we examine the effects of inhibition of telomerase inside human cells. Peptide nucleic acid and 2′ -O- MeRNA oligomers inhibit telomerase, leading to progressive telomere shortening and causing immortal human breast epithelial cells to undergo apoptosis with increasing frequency until no cells remain. Telomere shortening is reversible: if inhibitor addition is terminated, telomeres regain their initial lengths. Our results validate telomerase as a target for the discovery of anticancer drugs and supply general insights into the properties that successful agents will require regardless of chemical type. Chemically similar oligonucleotides are in clinical trials and have well characterized pharmacokinetics, making the inhibitors we describe practical lead compounds for testing for an antitelomerase chemotherapeutic strategy.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

Inhibiting telomerase in immortal human cells with 2′-O-MeRNA or PNA oligonucleotides caused progressive telomere shortening, apoptosis, and eventual loss of proliferation. Telomere shortening and growth arrest were reversible when inhibitor treatment was stopped.

Key findings

  • Complementary 2′-O-MeRNA inhibited >95% of telomerase activity 1 day after transfection and >70% at 3 days. HME50-5E proliferation slowed after 15–25 days, and no treated cells remained after 110 days; apoptosis rose from <5% during the first 60 days to 14% at 80 days and 56% at 100 days, versus 2–3% in controls.
  • DU145 cells began slowing after 60 days and had undergone 20 fewer population doublings than mismatch-treated cells by 120 days. HME50-hTERT cells, with longer telomeres, showed no significant growth reduction over 120 days.
  • Mean telomere restriction fragment length decreased from 2,000 to 1,700 bp in HME50-5E cells by 60 days, from 3,600 to 2,200 bp in DU145 cells by 76 days, and from 7,600 to 6,800 bp in HME50-hTERT cells after 75 days. A template-directed PNA inhibited >90% of telomerase activity at 1 day and shortened telomeres, whereas a nontemplate PNA inhibited only 50% and did not shorten telomeres.
  • After inhibitor withdrawal at 76 days, eroded telomeres returned to approximately initial lengths within 3 weeks, and previously static HME50-5E cells regained growth within 3 weeks. No evidence for an ALT pathway was observed.

Methods

  • Immortal human cell lines HME50-5E, DU145, and HME50-hTERT were transfected with 2′-O-MeRNA or PNA/DNA complexes using cationic lipids; treatment was repeated every 3–4 days for 120 days, with mismatch oligomers, lipid alone, or nontemplate PNA as controls.
  • Telomerase activity was measured by TRAP, mean telomere length by telomere restriction fragment Southern analysis, apoptosis by Annexin V flow cytometry, and proliferation by cell counts/population doublings.
  • Effects of matched versus mismatched or nontemplate inhibitors were compared over time to test sequence-specific, telomerase-dependent mechanisms.

Limitations

  • Stated in the paper: the TRF assay does not monitor subtelomeric erosion and may underestimate total telomeric DNA loss; 5–30% of telomerase activity remained after treatment; systemic telomerase inhibition would also affect normal stem cells; the long lag before phenotypic effects complicates drug development; and no ALT pathway was observed in these cell types, leaving applicability to ALT-positive tumors uncertain.
  • Evident from the text: findings are in vitro in a small number of immortal cell lines, including p53-mutant lines, with no animal or human efficacy/toxicity data; the 120-day culture experiments required stringent precautions against contamination but remain vulnerable to long-term culture artifacts.

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Integrity signals

Registry

Crossref · 10.1073/pnas.96.25.14276

Cites

47 of 47 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

32 Not checked yet · 31 Own result · 28 Own interpretation · 5 No basis given · 2 Own method

Verify all 49 references — free account

Show all 67 claims

  • It may state two separate claims as one. 14
  • Probably not a substantial claim. 23
31 of 31
  • The paper relies on this without support.

    The mice used in these experiments possessed much longer telomeres than those found in cancerous human cells.

    “the mice used in these experiments possessed much longer telomeres than those found in cancerous human cells”
  • The paper relies on this without support.

    Chemically similar oligonucleotides are in clinical trials and have well characterized pharmacokinetics.

    “Chemically similar oligonucleotides are in clinical trials and have well characterized pharmacokinetics”
  • The paper relies on this without support.

    HME50-5E cells were derived from HME50 preimmortal cells that had one mutant p53 allele and lost the second allele during spontaneous immortalization.

    “HME50-5E cells were derived from HME50 preimmortal cells that had one mutant p53 allele and lost the second allele during spontaneous immortalization”
  • The paper relies on this without support.

    DU145 cells have two mutant p53 alleles.

    “whereas DU145 cells have two mutant alleles”
  • The paper relies on this without support.

    The genetic background of HME50-hTERT cells is similar to that of HME50-5E cells.

    “even though the genetic background of HME50-hTERT cells is similar to that of HME50-5E cells”
  • The paper relies on this without support.

    HME50-5E cells have shorter telomeres than DU145 cells.

    “which have shorter telomeres than DU145 cells”
  • The paper relies on this without support.

    HME50-hTERT cells have an initial telomere length approximately 4,000 bp longer than that of HME50-5E cells.

    “their initial telomere length of HME50-hTERT cells is approximately 4,000 bp longer.”
7 of 7

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Citations

Cites

Show all 48 references

Research works printed but not linked: 5

  1. H Tahara, H Kuniyasu, H Yokozaki, W Yasui, J W Shay, T Ide, E Tahara Clin Cancer Res 1, 1245–1251 (1995).
  2. M Engelhardt, P Drullinsky, J Guillem, M A Moore Clin Cancer Res 3, 1931–1941 (1997).
  3. J H Ohyashiki, K Ohyashiki, I Iwama, S Hayashi, K Toyama, J W Shay Clin Cancer Res 3, 619–625 (1997).
  4. J W Shay, D Brasiskyte, M Ouellette, M A Piatyszek, H Werbin, Y Ying, W E Wright Methods Mol Genet 5, 263–268 (1994).
  5. C A Stein Antisense Res Dev 7, 207–209 (1997).

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Metadata

Authors
Herbert, B.-S., Pitts, A. E., Baker, S. I., Hamilton, S. E., Wright, W. E., Shay, J. W., & Corey, D. R.
Affiliations
Howard Hughes Medical Institute (US)
Venue
Proceedings of the National Academy of Sciences
Published
1999-12-07
Volume
96
Issue
25
Pages
14276-14281
ISSN
  • 0027-8424 (ISSN-L)
  • 1091-6490
OpenAlex
W2118228848
Cited by
539
References
48
Citations by year
2026: 1 · 2025: 1 · 2024: 5 · 2023: 7 · 2022: 5 · 2021: 6 · 2020: 5 · 2019: 11 · 2018: 9 · 2017: 9 · 2016: 5 · 2015: 18 · 2014: 7 · 2013: 12 · 2012: 13
FWCI
27.44
Type
journal article
Language
en
Open access
Locations
  • Proceedings of the National Academy of Sciences (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Howard Hughes Medical Institute
  • Ellison Medical Foundation
  • National Institutes of Health
  • National Cancer Institute (CA 74908, R01CA074908, CA-85143)
  • National Institute of General Medical Sciences (T32GM007062, T32GM07062-23)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Telomeres, Telomerase, and Senescence
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › DNA and Nucleic Acid Chemistry
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › RNA Interference and Gene Delivery
Keywords
telomerase inhibition, telomere shortening, apoptosis, peptide nucleic acid, 2'-O-methyl RNA, breast epithelial cells, cell immortalization, anticancer drug targets
MeSH terms
Antineoplastic Agents, Cell Division, Enzyme Inhibitors, Humans, Oligonucleotides, Telomere, Cell Death, Telomerase, Peptide Nucleic Acids

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