0000000000135639

AUTHOR

Maja Osmak

showing 5 related works from this author

Endoplasmic reticulum stress is involved in response of human laryngeal carcinoma cells to carboplatin but is absent in carboplatin resistant cells

2013

The major obstacle of successful tumor treatment with carboplatin (CBP) is the development of drug resistance. In the present study, we found that following treatment with CBP the amount of platinum which enters the human laryngeal carcinoma (HEp2)-derived CBP- resistant (7T) cells is reduced relative to the parental HEp2. As a consequence, the formation of reactive oxidative species (ROS) is reduced, the induction of endoplasmic reticulum (ER) stress is diminished, the amount of inter- and intrastrand cross-links is lower, and the induction of apoptosis is depressed. In HEp2 cells, ROS scavenger tempol, inhibitor of ER stress salubrinal, as well as gene silencing of ER stress marker CCAAT/…

Celllcsh:MedicineApoptosisCarboplatinSalubrinalapoptosis; carboplatin; drug resistance; endoplasmic reticulum stress; reactive oxidative species; tumor cellschemistry.chemical_compound0302 clinical medicineBlotting Southwesternlcsh:Science0303 health sciencesMultidisciplinaryThioureaGeologyEndoplasmic Reticulum Stress3. Good healthmedicine.anatomical_structure030220 oncology & carcinogenesisSignal transductionSignal TransductionResearch ArticleProgrammed cell deathCell SurvivalBlotting WesternBiologyReal-Time Polymerase Chain ReactionCyclic N-Oxides03 medical and health sciencesCell Line TumormedicineHumansGene SilencingLaryngeal NeoplasmsBiology030304 developmental biologyDNA PrimersPlatinumEndoplasmic reticulumlcsh:RCarcinomaMolecular biologychemistryCell cultureApoptosisCinnamatesDrug Resistance NeoplasmUnfolded protein responseCancer researchlcsh:QSpin LabelsReactive Oxygen Species
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Downregulation of RhoB GTPase confers resistance to cisplatin in human larygneal carcinoma cells

2009

Acquired resistance to cisplatin represents a major obstacle to an efficient chemotherapy. We found downregulation of RhoB expression in cisplatin-resistant tumor cell lines from different origin. In cisplatin-resistant laryngeal carcinoma subline overexpression of farnesylated or geranylgeranylated RhoB increased cisplatin-induced cell death, while silencing of RhoB expression diminished sensitivity of parental HEp-2 cells via decreased cellular accumulation of cisplatin. However, since RhoB silencing in additional tumor cell lines did not alter their sensitivity to cisplatin, we can assume that RhoB downregulation does not provide general protective role in cell response to cisplatin. Nev…

Cancer ResearchProgrammed cell deathGenetic enhancementRHOBmedicine.medical_treatmentDown-RegulationAntineoplastic AgentsBiologyDownregulation and upregulationCell Line TumormedicineCarcinomaHumansGene silencingrhoB GTP-Binding ProteinLaryngeal NeoplasmsCisplatinChemotherapymedicine.diseaseCell biologyOncologyDrug Resistance NeoplasmCancer researchcisplatin ; drug resistance ; Rho GTPases ; RhoBCisplatinmedicine.drug
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Late Activation of Stress-activated Protein Kinases/c-Jun N-terminal Kinases Triggered by Cisplatin-induced DNA Damage in Repair-defective Cells

2011

Although stress-activated protein kinases/c-Jun N-terminal kinases (SAPK/JNK) are rapidly activated by genotoxins, the role of DNA damage in this response is not well defined. Here we show that the SEK1/MKK4-mediated dual phosphorylation of SAPK/JNK (Thr-183/Tyr-185) correlates with the level of cisplatin-DNA adducts at late times (16–24 h) after drug treatment in both human and mouse cells. Transfection of platinated plasmid DNA also caused SAPK/JNK activation. A defect in transcription-coupled nucleotide excision repair resting on a mutation in Cockayne syndrome group B protein promoted the late SAPK/JNK activation following cisplatin exposure. Signaling to SAPK/JNK was accompanied by act…

rho GTP-Binding ProteinsDNA RepairMAP Kinase Kinase 4DNA repairDNA damageDNA damage response; DNA repair; cisplatin-DNA adducts; SAPK/JNKp38 mitogen-activated protein kinasesAntineoplastic AgentsCell Cycle ProteinsAtaxia Telangiectasia Mutated ProteinsProtein Serine-Threonine KinasesDNA and ChromosomesBiologyBiochemistryAtaxia Telangiectasia Mutated ProteinsDNA AdductsMiceRadiation IonizingAnimalsHumansDNA Breaks Double-StrandedMolecular BiologyReplication protein ACells CulturedMice KnockoutKinaseTumor Suppressor ProteinsJNK Mitogen-Activated Protein KinasesCell BiologyMolecular biologyDNA-Binding ProteinsEnzyme Activationc-Jun N-terminal kinasesbiology.proteinCisplatinSignal TransductionNucleotide excision repairJournal of Biological Chemistry
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Synthesis and biological evaluation of 4-nitro-substituted 1, 3-diaryltriazenes as a novel class of potent antitumor agents

2011

Abstract We describe the synthesis and biological activity of a new class of 1,3-diaryltriazenes, namely 4-nitro-substituted 1,3-diaryltriazenes. Structure–activity relationship analysis reveals that 1,3-diaryltriazenes can be modified from inactive to highly cytotoxic compounds by the introduction of two nitro groups at the para positions of benzene rings and two additional electron-withdrawing groups (bromo, chloro, trifluoromethyl or fluoro substituents) at their ortho position. In order to increase the solubility of the modified compounds, we introduced various acyl groups to their triazene nitrogen. The results of LC-MS/MS analysis showed that N -acyltriazenes can be considered as prod…

StereochemistryNitro compoundAntineoplastic AgentsApoptosis1 ; 3-diaryltriazenes ; synthesis ; cytotoxicity ; ROS induction ; apoptosisChemical synthesisNitrophenolschemistry.chemical_compoundStructure-Activity RelationshipCell Line TumorDrug DiscoveryCytotoxic T cellHumansProdrugsTriazeneCell ProliferationPharmacologychemistry.chemical_classificationChemistryOrganic ChemistryBiological activityGeneral MedicineDNA NeoplasmProdrugEndoplasmic Reticulum StressIn vitroDrug Resistance NeoplasmNitroCisplatinTriazenesReactive Oxygen Species
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Cisplatin sensitivity is related to late DNA damage processing and checkpoint control rather than to the early DNA damage response

2008

The present study aimed at elucidating mechanisms dictating cell death triggered by cisplatin-induced DNA damage. We show that CL-V5B hamster mutant cells, a derivative of V79B, are hypersensitive to cisplatin-induced apoptotic death. CL-V5B cells are characterized by attenuated cisplatin-induced early (2-6 h) stress response, such as phosphorylation of stress-activated protein kinases (SAPK/JNK), ATM and Rad3-related (ATR) protein kinase, histone H2AX and checkpoint kinase-1 (Chk-1). Human FANCC cells also showed a reduced phosphorylation of H2AX and SAPK/JNK at early time point after cisplatin treatment. This was not the case for BRCA2-defective VC-8 hamster cells, indicating that the FA …

Cell cycle checkpointCisplatin-DNA adducts ; DNA repair ; Interstrand cross links ; DNA damage response ; Cell cycle checkpoint ; Cell deathDNA damageDNA repairHealth Toxicology and MutagenesisApoptosisCell LineHistonesDNA AdductsCricetinaeGeneticsmedicineAnimalsHumansCHEK1PhosphorylationMolecular BiologyChromosome AberrationsCisplatinbiologyJNK Mitogen-Activated Protein KinasesDNA replicationG2-M DNA damage checkpointMolecular biologyCell biologyHistonebiology.proteinCisplatinDNA DamageMutagensmedicine.drug
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