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Microcell-mediated transfer of chromosome 4 into HeLa cells suppresses telomerase activity
C Backsch1, N Wagenbach, M Nonn
1Gynäkologische Molekularbiologie, Abteilung Frauenheilkunde, Frauenklinik der FSU Jena, Germany.
Abstract:
Telomerase activity can be detected in most human cancers and immortal cell lines. In contrast, the lack of telomerase activity in normal diploid fibroblasts has been correlated with progressive reduction of telomere lengths to critically short sizes followed by the cessation of cell division and the onset of senescence. Several investigators have provided evidence for the localization of a telomerase suppressor gene on chromosome 3. The aim of our study was to determine whether other chromosomes are involved in telomerase repression. Beside human chromosome 3 (serving as positive control), chromosomes 4, 6, and 11 were introduced into HeLa cells via microcell-mediated chromosome transfer. Telomerase activity from different hybrid cell lysates was determined at an early time point after fusion using a Telomerase ELISA kit. Strong repression of telomerase activity was only found in a subset of HeLa hybrids in which chromosome 3 or chromosome 4 had been introduced. Telomerase suppression induced by chromosome 3 or 4 transfer was paralleled by a high frequency (30% or 43%, respectively) of a senescent-like phenotype. Chromosomes 6 and 11, the functional loss of which is also implicated in cervical cancer, had no effect. These results indicate that normal human chromosomes 3 and 4 carry a gene or genes that suppress telomerase activity and induce cellular senescence in HeLa cells.
Insights
Human chromosomes 3 and 4 contain genes that suppress telomerase activity, a key factor in cancer cell immortality. Introducing these chromosomes into cancer cells also induced cellular senescence, halting their division.
Area of Science:
- Cell Biology
- Genetics
- Cancer Research
Background:
- Telomerase activity is prevalent in human cancers and immortal cell lines.
- Normal cells exhibit telomere shortening and senescence due to lack of telomerase.
- Previous studies suggested chromosome 3 harbors a telomerase suppressor gene.
Purpose of the Study:
- To investigate if other human chromosomes besides chromosome 3 are involved in telomerase repression.
- To identify specific chromosomes that can suppress telomerase activity and induce senescence in cancer cells.
Main Methods:
- Microcell-mediated chromosome transfer was used to introduce human chromosomes 3, 4, 6, and 11 into HeLa cells.
- Telomerase activity in hybrid cell lysates was quantified using a Telomerase ELISA kit.
- The induction of a senescent-like phenotype was assessed in the hybrid cells.
Main Results:
- Introduction of chromosome 3 or 4 into HeLa cells strongly repressed telomerase activity.
- Chromosome 3 and 4 transfer led to a high frequency of cellular senescence (30% and 43%, respectively).
- Chromosomes 6 and 11 did not significantly affect telomerase activity or induce senescence.
Conclusions:
- Human chromosomes 3 and 4 possess genes that effectively suppress telomerase activity.
- These chromosomes also play a role in inducing cellular senescence, offering potential therapeutic targets for cancer.
- The findings highlight the importance of specific chromosomal regions in regulating cancer cell proliferation and aging.
Related Concept Videos
02:41Telomeres and Telomerase
02:15Replicative Cell Senescence