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Maintenance of telomeres in SV40‐transformed pre‐immortal and immortal human fibroblasts
Author(s) -
Small Michael B.,
Hubbard Karen,
Pardinas Jose R.,
Marcus Alexander M.,
Dhanaraj Sridevi N.,
Sethi Khalid A.
Publication year - 1996
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/(sici)1097-4652(199609)168:3<727::aid-jcp26>3.0.co;2-u
Subject(s) - telomerase , telomere , immortalised cell line , senescence , carcinogenesis , biology , cell culture , microbiology and biotechnology , telomerase reverse transcriptase , cell , cancer research , genetics , dna , cancer , gene
Shortening of telomeres has been hypothesized to contribute to cellular senescence and may play a role in carcinogenesis of human cells. Furthermore, activation of telomerase has frequently been demonstrated in tumor‐derived and in vitro immortalized cells. In this study, we have assessed these phenomena during the life span of simian virus 40 (SV40)‐transformed preimmortal and immortal human fibroblasts. We observed progressive reduction in telomere length in preimmortal transformed cells with extended proliferative capacity, with the most dramatic shortening at late passage. Telomere lengths became stabilized (or increased) in immortal fibroblasts accompanied, in one case, by the activation of telomerase. However, an independent immortal cell line that displayed stable telomeres did not have detectable telomerase activity. Furthermore, we found significant telomerase activity in two preimmortal derivatives. Our results provide further evidence for maintenance of telomeres in immortalized human fibroblasts, but they suggest a lack of causal relationship between telomerase activation and immortalization. © 1996 Wiley‐Liss, Inc.