Proteome alteration induced by hTERT transfection of human fibroblast cells

Gabriel D Mazzucchelli¹ , Valérie Gabelica¹ , Nicolas Smargiasso¹ , Maximilien Fléron¹ , Wilson Ashimwe¹ , Frédéric Rosu¹ , Marie-Claire De Pauw-Gillet² , Jean-François Riou³ and Edwin De Pauw¹

¹Laboratory of Mass Spectrometry; CART, GIGA, University of Liège, BAT. B6C, allée de la Chimie, 3, 4000 Liège 1, Belgium

²Histology and Cytology Laboratory, GIGA, University of Liège, BAT. B6C, allée de la Chimie, 3, 4000 Liège 1, Belgium

³Regulation et Dynamique des Genomes, Museum National d'Histoire Naturelle, USM 503, INSERM U565, CNRS UMR 5153, Paris, France

author email corresponding author email

Proteome Science 2008, 6:12doi:10.1186/1477-5956-6-12


Published:	17 April 2008

Abstract

Background

Telomerase confers cellular immortality by elongating telomeres, thereby circumventing the Hayflick limit. Extended-life-span cells have been generated by transfection with the human telomerase reverse transcriptase (hTERT) gene. hTERT transfected cell lines may be of outstanding interest to monitor the effect of drugs targeting the telomerase activity. The incidence of hTERT gene transfection at the proteome level is a prerequisite to that purpose. The effect of the transfection has been studied on the proteome of human fibroblast (WI38). Cytosolic and nuclear fractions of WI38 cells, empty vector transfected WI38 (WI38-HPV) and hTERT WI38 cells were submitted to a 2D-DIGE (Two-Dimensional Differential In-Gel Electrophoresis) analysis. Only spots that had a similar abundance in WI38 and WI38-HPV, but were differentially expressed in WI38 hTERT were selected for MS identification. This method directly points to the proteins linked with the hTERT expression. Number of false positive differentially expressed proteins has been excluded by using control WI38-HPV cells. The proteome alteration induced by hTERT WI38 transfection should be taken into account in subsequent use of the cell line for anti-telomerase drugs evaluation.

Results

2D-DIGE experiment shows that 57 spots out of 2246 are significantly differentially expressed in the cytosolic fraction due to hTERT transfection, and 38 were confidently identified. In the nuclear fraction, 44 spots out of 2172 were selected in the differential proteome analysis, and 14 were identified. The results show that, in addition to elongating telomeres, hTERT gene transfection has other physiological roles, among which an enhanced ER capacity and a potent cell protection against apoptosis.

Conclusion

We show that the methodology reduces the complexity of the proteome analysis and highlights proteins implicated in other processes than telomere elongation. hTERT induced proteome changes suggest that telomerase expression enhances natural cell repair mechanisms and stress resistance probably required for long term resistance of immortalized cells. Thus, hTERT transfected cells can not be only consider as an immortal equivalent to parental cells but also as cells which are over-resistant to stresses. These findings are the prerequisite for any larger proteomics aiming to evaluate anti-telomerase drugs proteome alteration and thus therapeutics induced cell reactions.