title: Cellular redox imbalance and changes of protein S-glutathionylation patterns are associated with senescence induced by oncogenic H-ras.
abstract: H-Ras oncogene requires deregulation of additional oncogenes or inactivation of tumor suppressor proteins to increase cell proliferation rate and transform cells. In fact, the expression of the constitutively activated H-RasV12 induces cell growth arrest and premature senescence, which act like barriers in pre-neoplastic lesions. In our experimental model, human fibroblasts transfected with H-RasV12 show a dramatic modification of morphology. H-RasV12 expressing cells also show premature senescence followed by cell death, induced by autophagy and apoptosis. In this context, we provide evidence that in H-RasV12 expressing cells, the premature senescence is associated with cellular redox imbalance as well as with altered post-translation protein modification. In particular, redox imbalance is due to a strong reduction of total antioxidant capacity, and significant decrease of glutathione level. As the reversible addition of glutathione to cysteinyl residues of proteins is an important post-translational regulative modification, we investigated S-glutathionylation in cells expressing active H-Ras. In this contest we observed different S-glutathionylation patterns in control and H-RasV12 expressing cells. Particularly, the GAPDH enzyme showed S-glutathionylation increase and significant enzyme activity depletion in H-Ras V12 cells. In conclusion, we proposed that antioxidant defense reduction, glutathione depletion and subsequent modification of S-glutathionylation of target proteins contribute to arrest cell growth, leading to death of fibroblasts expressing constitutively active H-Ras oncogene, thus acting as oncogenic barriers that obstacle the progression of cell transformation.
authors.affiliation: Department of Clinical Sciences, Section of Biochemistry, Biology and Physics, Università Politecnica delle Marche, Ancona, Italy. t.armeni@univpm.it
authors.forename: Tatiana
authors.initials: T
authors.lastname: Armeni
authors.forename: Luisa
authors.initials: L
authors.lastname: Ercolani
authors.forename: Lorena
authors.initials: L
authors.lastname: Urbanelli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Magini
authors.forename: Francesca
authors.initials: F
authors.lastname: Magherini
authors.forename: Armanda
authors.initials: A
authors.lastname: Pugnaloni
authors.forename: Francesco
authors.initials: F
authors.lastname: Piva
authors.forename: Alessandra
authors.initials: A
authors.lastname: Modesti
authors.forename: Carla
authors.initials: C
authors.lastname: Emiliani
authors.forename: Giovanni
authors.initials: G
authors.lastname: Principato
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D001343:Autophagy / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D016923:Cell Death / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D016922:Cellular Senescence / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D015180:Electrophoresis, Gel, Two-Dimensional; D011905:Genes, ras / Q000235:genetics / Q000502:physiology*; D006801:Humans; D015151:Immunoblotting; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species