title: Proteomic profiling in distinct cellular compartments of tumor cells reveals p53-dependent upregulation of S100A6 upon induction of telomere dysfunction.
abstract: Telomere dysfunction is evoking a DNA damage response which leads to replicative senescence or apoptosis. Tumor cells feature telomerase, a ribonucleoprotein complex counteracting telomere shortening and proliferation limitation as a prerequisite of immortal cell growth. Recently, we demonstrated the effects of telomerase inhibition on the proteome of tumor cell clones in whole cell lysates by SELDI-TOF-MS profiling and MS/MS protein identification (Zimmermann et al., Proteomics 2009, 9, 521-534). We continued proteomic analyses of such clones after telomerase-inhibition using fractionation of cellular compartments. Among the differentially expressed peaks found in different fractions, a cytoplasmic 10.1 kDa protein upregulated in telomerase-inhibited clones (p<0.0001) was identified by nanoflow-HPLC-MS/MS as S100A6. S100A6 upregulation was confirmed by immunoblotting in telomerase-inhibited HCT-116, A-549, and NCI-H460 clones. S100A6 and other proteins involved in telomere dysfunction were further analyzed in derivative p53(-/-) and p21(-/-) HCT-116 cell lines indicating an overall reduced number of significant changes in these lines compared to wild type HCT-116 cells. In addition, post-translational modification of S100A6 was demonstrated with a potential role in mediating the cellular response to telomere dysfunction. In conclusion, proteomic profiling in distinct cellular compartments led to the identification of a novel p53-dependent biomarker of telomere dysfunction, S100A6.
authors.affiliation: University Medical Center Freiburg, Department of Hematology/Oncology, Hugstetter Strasse 55, Freiburg, Germany. stefan.zimmermann@uniklinik-freiburg.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Zimmermann
authors.forename: Martin L
authors.initials: ML
authors.lastname: Biniossek
authors.forename: Christian
authors.initials: C
authors.lastname: Maurer
authors.forename: Patrick
authors.initials: P
authors.lastname: Münzer
authors.forename: Milena
authors.initials: M
authors.lastname: Pantic
authors.forename: Hendrik
authors.initials: H
authors.lastname: Veelken
authors.forename: Uwe M
authors.initials: UM
authors.lastname: Martens
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D020869:Gene Expression Profiling; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D040901:Proteomics; D000075383:S100 Calcium Binding Protein A6; D009418:S100 Proteins / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D019098:Telomerase / Q000235:genetics / Q000378:metabolism; D016615:Telomere / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D018797:Cell Cycle Proteins; D000075383:S100 Calcium Binding Protein A6; D009418:S100 Proteins; D016159:Tumor Suppressor Protein p53; C055351:S100A6 protein, human; D019098:Telomerase