Tumor necrosis factor alpha induces senescence and chromosomal instability in human leukemic cells.
Previous studies have documented that Tumor necrosis factor alpha (TNFalpha) is a potent negative regulator of normal hematopoiesis. However, the mechanism by which TNFalpha acts at the cellular level is not totally understood. Although apoptotic cell killing appears to be the most common cellular effect of TNFalpha, other studies suggest that this cytokine may elicit other cellular responses such as prolonged growth inhibition. In this context, we have investigated whether TNFalpha may induce senescence in hematopoietic cells, which display intrinsic defect in the apoptotic machinery. The present study described that, in the leukemic KG1 cells, TNFalpha induced no apoptosis but a senescence state characterized by prolonged growth arrest, increased beta-galactosidase activity, p21WAF-1 induction, decreased telomerase activity, telomeric disturbances (shortening, losses, fusions), and additional chromosomal aberrations. Telomerase inhibition correlated with reduced levels of hTERT transcripts. GM-CSF prevented TNFalpha effects and allowed leukemic cells to recover growth capacity. Finally, our study shows for the first time that, at least in some hematopoietic cells, TNFalpha may induce senescence with important functional consequences, including sustained growth inhibition and genetic instability, and that this cellular response is efficiently regulated by hematopoietic growth factors.
Institut National de la Santé et de la Recherche Médicale U563, Centre de Physiopathologie de Toulouse Purpan, Place du Docteur Baylac, 31059, France.
Odile
O
Beyne-Rauzy
Christian
C
Recher
Nicole
N
Dastugue
Cécile
C
Demur
Géraldine
G
Pottier
Guy
G
Laurent
Laure
L
Sabatier
Véronique
V
Mansat-De Mas
D001483:Base Sequence; D045744:Cell Line, Tumor; D016922:Cellular Senescence; D043171:Chromosomal Instability; D017931:DNA Primers; D004268:DNA-Binding Proteins; D006801:Humans; D016130:Immunophenotyping; D015470:Leukemia, Myeloid, Acute / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D019098:Telomerase / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
D017931:DNA Primers; D004268:DNA-Binding Proteins; D014409:Tumor Necrosis Factor-alpha; D019098:Telomerase