title: Limited proliferation and telomere dysfunction following telomerase inhibition in immortal murine fibroblasts.
abstract: Telomerase is a ribonucleoprotein enzyme that functions to maintain telomeres, the terminal DNA that protects chromosomal integrity, regulating cellular replicative life span. Telomerase is not expressed in most normal human somatic cells but is active in stabilizing telomeres of certain self-renewing cell populations and most malignant cells, making the enzyme an appealing target for anticancer therapy. We describe here a novel cross-species approach to telomerase inhibition. Ectopic expression of the human telomerase catalytic reverse transcriptase component in murine cells inhibited endogenous murine telomerase activity. Using this approach, telomerase inhibition in immortal murine fibroblasts resulted in critical telomere shortening, leading to slowed proliferation, abnormal morphology, altered cell cycle, and telomere dysfunction with cytogenetic instability, followed by apoptotic cell death. Subpopulations of two telomerase-inhibited clones escaped widespread apoptosis, showing proliferative recovery in culture despite persistently inhibited telomerase activity with progressive telomere shortening and dysfunction. This study, by targeting immortal murine cells for telomerase inhibition, demonstrates the importance of telomerase to murine cell immortalization and telomere maintenance. Moreover, the murine model used here should prove useful in further evaluating telomerase inhibition as an anticancer therapy.
authors.affiliation: James Ewing Laboratory of Developmental Hematopoiesis, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Boklan
authors.forename: Gouri
authors.initials: G
authors.lastname: Nanjangud
authors.forename: Karen L
authors.initials: KL
authors.lastname: MacKenzie
authors.forename: Chad
authors.initials: C
authors.lastname: May
authors.forename: Michel
authors.initials: M
authors.lastname: Sadelain
authors.forename: Malcolm A S
authors.initials: MA
authors.lastname: Moore
mesh_terms: D016475:3T3 Cells; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D004268:DNA-Binding Proteins; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology* / Q000502:physiology; D006801:Humans; D051379:Mice; D019098:Telomerase / Q000037:antagonists & inhibitors* / Q000235:genetics; D016615:Telomere / Q000502:physiology*; D014161:Transduction, Genetic
chemical_list: D004268:DNA-Binding Proteins; D019098:Telomerase