title: Telomere loss, senescence, and genetic instability in CD4+ T lymphocytes overexpressing hTERT.
abstract: Little is known about the long-term consequences of overexpression of the human telomerase reverse transcriptase (hTERT) gene in T lymphocytes. To address this issue, we transduced polyclonal as well as clonally derived populations of naive and memory CD44 T cells from 2 healthy donors (aged 24 and 34 years) with retroviral vectors encoding green fluorescence protein (GFP) and hTERT (GFP-hTERT) or GFP alone. After transduction, cells were sorted on the basis of GFP expression and cultured in vitro until senescence. T cells transduced with hTERT exhibited high stable telomerase activity throughout the culture period. Relative to GFP controls, minor changes in overall gene expression were observed yet the proliferative lifespan of the hTERT-transduced populations was significantly increased and the rate of telomere loss was lower. Nevertheless, hTERT-transduced cells showed progressive telomere loss and had shorter telomeres at senescence than controls (2.3 +/- 0.3 kilobase [kb] versus 3.4 +/- 0.1 kb). Furthermore, a population of cells with 4N DNA consisting of binucleated cells with connected nuclei emerged in the hTERT-transduced cells prior to senescence. We conclude that overexpression of hTERT in CD4+ T cells provides a proliferative advantage independent of the average telomere length but does not prevent eventual genetic instability and replicative senescence.
authors.affiliation: Terry Fox Laboratory, British Columbia Cancer Agency, 12th floor, 675 W 10th Ave, Vancouver, BC, V5Z 1L3, Canada.
authors.forename: Alexander
authors.initials: A
authors.lastname: Röth
authors.forename: Gabriela M
authors.initials: GM
authors.lastname: Baerlocher
authors.forename: Mike
authors.initials: M
authors.lastname: Schertzer
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Chavez
authors.forename: Ulrich
authors.initials: U
authors.lastname: Dührsen
authors.forename: Peter M
authors.initials: PM
authors.lastname: Lansdorp
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000502:physiology; D002455:Cell Division / Q000276:immunology; D002467:Cell Nucleus; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000276:immunology*; D004268:DNA-Binding Proteins; D015870:Gene Expression / Q000276:immunology; D020869:Gene Expression Profiling; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D007156:Immunologic Memory / Q000502:physiology; D019098:Telomerase / Q000235:genetics* / Q000378:metabolism; D016615:Telomere / Q000378:metabolism*; D014161:Transduction, Genetic
chemical_list: D004268:DNA-Binding Proteins; D049452:Green Fluorescent Proteins; D019098:Telomerase
references.citation: J Biol Chem. 2003 May 30;278(22):19904-8
references.pmid: 12665523
references.citation: Genes Dev. 1999 Sep 15;13(18):2388-99
references.pmid: 10500096
references.citation: Cell. 2003 Jul 25;114(2):241-53
references.pmid: 12887925
references.citation: Cytometry A. 2003 Sep;55(1):1-6
references.pmid: 12938182
references.citation: Nature. 2003 Nov 13;426(6963):194-8
references.pmid: 14608368
references.citation: Leukemia. 2003 Dec;17(12):2410-7
references.pmid: 14562114
references.citation: Mol Ther. 2004 Jan;9(1):5-13
references.pmid: 14741772
references.citation: J Exp Med. 2004 May 17;199(10):1433-43
references.pmid: 15148341
references.citation: Annu Rev Biochem. 2004;73:177-208
references.pmid: 15189140
references.citation: Nat New Biol. 1972 Oct 18;239(94):197-201
references.pmid: 4507727
references.citation: J Theor Biol. 1973 Sep 14;41(1):181-90
references.pmid: 4754905
references.citation: Proc Natl Acad Sci U S A. 1988 Sep;85(18):6622-6
references.pmid: 3413114
references.citation: Nature. 1990 May 31;345(6274):458-60
references.pmid: 2342578
references.citation: J Virol. 1991 May;65(5):2220-4
references.pmid: 1850008
references.citation: J Natl Cancer Inst. 1994 Aug 3;86(15):1159-66
references.pmid: 8028037
references.citation: Science. 1994 Dec 23;266(5193):2011-5
references.pmid: 7605428
references.citation: Gene Ther. 1994 Mar;1(2):136-8
references.pmid: 7584069
references.citation: Proc Natl Acad Sci U S A. 1995 Nov 21;92(24):11190-4
references.pmid: 7479963
references.citation: J Exp Med. 1996 Jun 1;183(6):2471-9
references.pmid: 8676067
references.citation: Exp Cell Res. 1996 Oct 10;228(1):58-64
references.pmid: 8892971
references.citation: J Immunol. 1997 Apr 1;158(7):3215-20
references.pmid: 9120276
references.citation: Exp Cell Res. 1997 Mar 15;231(2):346-53
references.pmid: 9087176
references.citation: Nucleic Acids Res. 1997 Jul 1;25(13):2595-7
references.pmid: 9185569
references.citation: Immunol Today. 1997 Sep;18(9):450-4
references.pmid: 9293162
references.citation: Biochem Biophys Res Commun. 1999 Dec 9;266(1):115-22
references.pmid: 10581175
references.citation: Nat Biotechnol. 2000 Apr;18(4):405-9
references.pmid: 10748520
references.citation: Exp Cell Res. 2000 Apr 10;256(1):291-9
references.pmid: 10739676
references.citation: Nature. 2000 Aug 10;406(6796):641-5
references.pmid: 10949306
references.citation: Mech Ageing Dev. 2000 Sep 1;118(1-2):23-34
references.pmid: 10989122
references.citation: J Immunol. 2000 Oct 15;165(8):4239-45
references.pmid: 11035057
references.citation: J Neurosci Res. 2001 Jan 1;63(1):1-9
references.pmid: 11169608
references.citation: EMBO J. 2001 Jun 1;20(11):2619-30
references.pmid: 11387197
references.citation: Curr Top Microbiol Immunol. 2001;258:221-9
references.pmid: 11443864
references.citation: Blood. 2001 Aug 1;98(3):597-603
references.pmid: 11468156
references.citation: Cell. 2001 Oct 5;107(1):67-77
references.pmid: 11595186
references.citation: Proc Natl Acad Sci U S A. 2001 Oct 23;98(22):12683-8
references.pmid: 11675499
references.citation: Oncogene. 2002 Jan 21;21(4):564-79
references.pmid: 11850781
references.citation: Blood. 2002 Jun 1;99(11):3916-22
references.pmid: 12010789
references.citation: Proc Natl Acad Sci U S A. 2002 Jun 11;99(12):8191-6
references.pmid: 12034875
references.citation: AIDS. 2002 Jul 26;16(11):1467-78
references.pmid: 12131184
references.citation: Hematology Am Soc Hematol Educ Program. 2002;:369-91
references.pmid: 12446433
references.citation: Lancet. 2003 Feb 1;361(9355):393-5
references.pmid: 12573379
references.citation: Nat Med. 2003 Mar;9(3):279-86
references.pmid: 12579196
references.citation: Nat Rev Cancer. 2003 May;3(5):339-49
references.pmid: 12724732
references.citation: Science. 1998 Jan 16;279(5349):349-52
references.pmid: 9454332
references.citation: Curr Biol. 1998 Feb 26;8(5):279-82
references.pmid: 9501072
references.citation: J Virol. 1998 Jun;72(6):4882-92
references.pmid: 9573255
references.citation: J Immunol. 1998 Jun 15;160(12):5702-6
references.pmid: 9637478
references.citation: Immunity. 1998 Aug;9(2):151-7
references.pmid: 9729035
references.citation: J Immunol. 1998 Nov 15;161(10):5133-7
references.pmid: 9820481
references.citation: Nat Genet. 1999 Jan;21(1):111-4
references.pmid: 9916802
references.citation: Nat Genet. 1999 Jan;21(1):115-8
references.pmid: 9916803
references.citation: Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3723-8
references.pmid: 10097104
references.citation: Proc Natl Acad Sci U S A. 1999 Apr 27;96(9):5147-52
references.pmid: 10220433
references.citation: Cell. 1999 May 14;97(4):503-14
references.pmid: 10338214
references.citation: Curr Opin Genet Dev. 1999 Jun;9(3):368-73
references.pmid: 10377284
references.citation: J Exp Med. 1999 Jul 19;190(2):157-67
references.pmid: 10432279
references.citation: Blood. 2003 Aug 1;102(3):849-57
references.pmid: 12689947