title: TGF-β/NF1/Smad4-mediated suppression of ANT2 contributes to oxidative stress in cellular senescence.
abstract: Oxidative stress and persistent activation of DNA damage response (DDR) are causally involved in the development of cellular senescence, a phenomenon implicated in fundamental (patho)physiological processes such as aging, fetal development and tumorigenesis. Here, we report that adenine nucleotide translocase-2 (ANT2) is consistently down-regulated in all three major forms of cellular senescence: replicative, oncogene-induced and drug-induced, in both normal and cancerous human cells. We previously reported formation of novel NF1/Smad transcription repressor complexes in growth-arrested fibroblasts. Here we show that such complexes form in senescent cells. Mechanistically, binding of the NF1/Smad complexes to the NF1-dependent repressor elements in the ANT2 gene promoter repressed ANT2 expression. Etoposide-induced formation of these complexes and repression of ANT2 were relatively late events co-incident with production and secretion of, and dependent on, TGF-β. siRNA-mediated knock-down of ANT2 in proliferating cells resulted in increased levels of reactive oxygen species (ROS) and activation of the DDR. Knock-down of ANT2, together with etoposide treatment, further intensified ROS production and DNA damage signaling, leading to enhanced apoptosis. Together, our data show that TGF-β-mediated suppression of ANT2 through NF1/Smad4 complexes contributes to oxidative stress and DNA damage during induction of cellular senescence.
authors.affiliation: Cancer Research Institute, Slovak Academy of Sciences, Vlarska 7, 833 91 Bratislava, Slovak Republic. Electronic address: miroslava.kretova@savba.sk.
authors.forename: Miroslava
authors.initials: M
authors.lastname: Kretova
authors.affiliation: Cancer Research Institute, Slovak Academy of Sciences, Vlarska 7, 833 91 Bratislava, Slovak Republic. Electronic address: ludmila.sabova@savba.sk.
authors.forename: Ludmila
authors.initials: L
authors.lastname: Sabova
authors.affiliation: Department of Genome Integrity, Institute of Molecular Genetics, v.v.i., Academy of Sciences of the Czech Republic, Videnska 1083, 14220 Prague, Czech Republic. Electronic address: zdenek.hodny@img.cas.cz.
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Hodny
authors.affiliation: Department of Genome Integrity, Institute of Molecular Genetics, v.v.i., Academy of Sciences of the Czech Republic, Videnska 1083, 14220 Prague, Czech Republic; Danish Cancer Society Research Center, Copenhagen, Denmark. Electronic address: jb@cancer.dk.
authors.forename: Jiri
authors.initials: J
authors.lastname: Bartek
authors.affiliation: Cancer Research Institute, Slovak Academy of Sciences, Vlarska 7, 833 91 Bratislava, Slovak Republic. Electronic address: kollarovic.gabor@gmail.com.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Kollarovic
authors.affiliation: Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, S-106 91 Stockholm, Sweden. Electronic address: buck.nelson@gmail.com.
authors.forename: Buck D
authors.initials: BD
authors.lastname: Nelson
authors.affiliation: Department of Genome Integrity, Institute of Molecular Genetics, v.v.i., Academy of Sciences of the Czech Republic, Videnska 1083, 14220 Prague, Czech Republic. Electronic address: sona.hubackova@img.cas.cz.
authors.forename: Sona
authors.initials: S
authors.lastname: Hubackova
authors.affiliation: Cancer Research Institute, Slovak Academy of Sciences, Vlarska 7, 833 91 Bratislava, Slovak Republic. Electronic address: katarina.luciakova@savba.sk.
authors.forename: Katarina
authors.initials: K
authors.lastname: Luciakova
mesh_terms: D033742:Adenine Nucleotide Translocator 2 / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D016922:Cellular Senescence / Q000187:drug effects; D019610:Cytoprotection / Q000187:drug effects; D004249:DNA Damage; D015536:Down-Regulation / Q000187:drug effects; D005047:Etoposide / Q000494:pharmacology; D006801:Humans; D009154:Mutation; D051839:NFI Transcription Factors / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000378:metabolism; D051901:Smad4 Protein / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism*
chemical_list: D033742:Adenine Nucleotide Translocator 2; D051839:NFI Transcription Factors; D012097:Repressor Proteins; D051901:Smad4 Protein; D016212:Transforming Growth Factor beta; D005047:Etoposide
keywords: Adenine nucleotide translocase-2; Nuclear factor 1; Oxidative stress; Senescence; Smad; Transforming growth factor-β