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Updated: Aug 21, 2026
Techniques to Induce and Quantify Cellular Senescence
Published on: May 1, 2017
Signaling pathway requirements for induction of senescence by telomere homolog oligonucleotides
Guang-Zhi Li1, Mark S Eller, Kendra Hanna
1Department of Dermatology, Boston University School of Medicine, Boston, MA 02118-2394, USA.
Abstract:
Cellular senescence is a major defense against cancer. In human fibroblasts, suppressing both the p53 and pRb pathways is necessary to bypass replicative senescence as well as senescence induced by ectopic expression of a dominant negative form of the telomere repeat binding factor 2, TRF2(DN). We recently reported that exposure to oligonucleotides homologous to the telomere 3' overhang (T-oligos) activates both the p53 and pRb pathways and leads to senescence in primary human fibroblasts. To further characterize T-oligo-induced senescence, we compared established isogenic fibroblast cell lines lacking functional p53 and/or pRb pathways to the normal parental line. Here, we report that, as in physiologic senescence, inactivation of both the p53 and pRb pathways is necessary to suppress T-oligo-induced senescence. Moreover, T-oligo rapidly induces senescence in a malignant fibroblast-derived cell line, demonstrating the potential of using T-oligo as a novel anticancer therapeutic. Our data support the hypothesis that exposure of the TTAGGG tandem repeat telomere 3' overhang sequence is the event that initiates signaling through DNA damage response pathways after experimental telomere disruption, serial passage, or acute genomic damage of normal cells.
Insights
Telomere oligonucleotides (T-oligos) trigger cellular senescence, a cancer defense mechanism, by activating p53 and pRb pathways. Suppressing both pathways is crucial to bypass this T-oligo-induced senescence, suggesting therapeutic potential.
Area of Science:
- Cell Biology
- Cancer Research
- Genetics
Background:
- Cellular senescence acts as a critical tumor suppressor mechanism.
- The p53 and pRb pathways are key regulators of senescence.
- Telomere integrity plays a role in preventing uncontrolled cell proliferation.
Purpose of the Study:
- To investigate the role of p53 and pRb pathways in T-oligo-induced senescence.
- To characterize the cellular response to T-oligo exposure in human fibroblasts.
- To evaluate the potential of T-oligos as an anticancer therapeutic.
Main Methods:
- Comparison of isogenic fibroblast cell lines with varying p53 and pRb pathway functionality.
- Induction of senescence using telomere oligonucleotides (T-oligos).
- Analysis of senescence markers and pathway activation.
Main Results:
- Inactivation of both p53 and pRb pathways is required to suppress T-oligo-induced senescence.
- T-oligos rapidly induce senescence in malignant fibroblast-derived cell lines.
- T-oligo exposure activates the p53 and pRb pathways, initiating DNA damage response signaling.
Conclusions:
- T-oligo-induced senescence relies on functional p53 and pRb pathways, similar to physiological senescence.
- T-oligos show promise as a novel therapeutic agent for cancer treatment.
- The TTAGGG telomere 3' overhang sequence is a key trigger for DNA damage response pathways.
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