title: Proteomic analysis of MOLT-4 cells treated by valproic acid.
abstract: The effect of valproic acid (VA) on protein expression in human T-lymphocytic leukemia cells MOLT-4 was studied. VA is an inhibitor of histonedeacetylases and has a potential use as antitumor agent in leukemia treatment. The authors in this work prove that 4 h long incubation with 2 mmol/l VA causes phosphorylation of histone H2A.X and its colocalization with 53BP1 in nuclear foci. Their co-localization is typical for DSB signaling machinery. These foci were detected in cells after 4 h exposure without increase of Annexin V positive apoptotic cells. Slight increase in apoptosis (Annexin V positivity) after 24 h is accompanied by more intensive increase in phosphorylation of H2A.X and also by formation of nuclear foci containing gammaH2A.X and 53BP1. Treatment of cells with 2 mmol/l VA resulted in induction of apoptosis affecting about 30% of cells after incubation for 72 h. The changes in protein expression were examined after cell incubation with 2 mmol/l VA for 4 h. Proteins were separated by two-dimensional electrophoresis and quantified using image evaluation system. Those exhibiting significant VA-induced abundance alterations were identified by mass spectrometry. Changes in expression of 22 proteins were detected, of which 15 proteins were down-regulated. Proteomic analysis resulted in successful identification of three proteins involving alfa-tubulin 3, tubulin-specific chaperone and heterogeneous nuclear ribonucloprotein F. Expression of seven proteins was up-regulated, including heterogeneous nuclear ribonucloprotein A/B. Identified proteins are related to microtubular system and hnRNP family. Suppression of microtubular proteins and changes of balance among hnRNPs can contribute to proliferation arrest and apoptosis induction.
authors.affiliation: Department of Radiobiology and Department of Molecular Pathology, School of Military Health Sciences Hradec Králové, University of Defense Brno, Trebesská 1575, 500 01, Hradec Kralove, Czech Republic. vavrova@pmfhk.cz
authors.forename: Jirina
authors.initials: J
authors.lastname: Vávrová
authors.forename: Sylva
authors.initials: S
authors.lastname: Janovská
authors.forename: Martina
authors.initials: M
authors.lastname: Rezácová
authors.forename: Lenka
authors.initials: L
authors.lastname: Hernychová
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Tichá
authors.forename: Doris
authors.initials: D
authors.lastname: Vokurková
authors.forename: Darina
authors.initials: D
authors.lastname: Záskodová
authors.forename: Emilie
authors.initials: E
authors.lastname: Lukásová
mesh_terms: D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D015180:Electrophoresis, Gel, Two-Dimensional; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005434:Flow Cytometry; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000378:metabolism; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D015458:Leukemia, T-Cell / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D009363:Neoplasm Proteins / Q000378:metabolism*; D020543:Proteome / Q000032:analysis*; D015398:Signal Transduction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014635:Valproic Acid / Q000494:pharmacology*
chemical_list: D017304:Annexin A5; D004791:Enzyme Inhibitors; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D056572:Histone Deacetylase Inhibitors; D009363:Neoplasm Proteins; D020543:Proteome; D014635:Valproic Acid