RESUMO
Long-term therapy with low Aspirin (ASA) dose is basis to prevent thrombotic acute events. However, the anti-platelet mechanisms of ASA remain not completely known. The aim was to analyze if in vitro exposure of human megakaryocytes to low ASA concentration may alter the apoptotic features of the newly formed platelets. Cultured Meg-01 cells, a human megakaryoblastic cell line, were stimulated to form platelets with 10 nmol/L phorbol 12-myristate-13-acetate (PMA) in the presence and absence of ASA (0.33 mmol/L). Results revealed that platelet-like particles (PLPs) derived from ASA-exposed Meg-01 cells, showed higher content of pro-apoptotic proteins Bax and Bak than PLPs from non-ASA incubated Meg-01 cells. It was accompanied of reduced cytochrome C oxidase activity and higher mitochondrial content of PTEN-induced putative kinase-1 in PLPs from ASA-incubated Meg-01 cells. However, only after calcium ionophore A23187 stimulation, caspase-3 activity, the cytosolic cytochrome C content, and reduction of mitochondrial membrane potential were higher in PLPs from ASA-incubated megakaryocytes than in those from Meg-01 without ASA. Nitric oxide synthase 3 content was higher in PLPs from ASA-exposed Meg-01 cells than in PLPs from non-ASA incubated Meg-01 cells. The L-arginine antagonist, NG-Nitro-L-arginine Methyl Ester, reduced caspase-3 activity in A23187-stimulated PLPs generated from ASA-incubated Meg-01 cells. As conclusions exposure of megakaryocyte to ASA promotes that the newly generated PLPs have, under stimulating condition, higher sensitivity to go into apoptosis than those PLPs generated from Meg-01 cells without ASA. It could be associated with differences in mitochondrial functionality and NO formation.
Assuntos
Apoptose/efeitos dos fármacos , Aspirina/uso terapêutico , Plaquetas/efeitos dos fármacos , Potencial da Membrana Mitocondrial/imunologia , Aspirina/farmacologia , HumanosAssuntos
Proteína 10 de Linfoma CCL de Células B/deficiência , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Proteína 10 de Linfoma CCL de Células B/genética , Linhagem Celular , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Recombinação Homóloga , Humanos , Peróxido de Hidrogênio/toxicidade , Hidroxiureia/toxicidadeRESUMO
Breast cancer is the most common and significant cancers in females regarding the loss of life quality. Similar to other cancers, one of the etiologic factors in breast cancer is DNA damage. A plethora of molecules are responsible for sensing DNA damage and mediating actions which lead to DNA repair, senescence, cell cycle arrest and if damage is unbearable to apoptosis. In each of these, aberrations leading to unrepaired damage was resulted in uncontrolled proliferation and cancer. Another cellular function is autophagy defined as a process eliminating of unnecessary proteins in stress cases involved in pathogenesis of cancer. Knowing their role in cancer, scholars have tried to develop strategies in order to target DDR and autophagy. Further, the interactions of DDR and autophagy plus their regulatory role on each other have been focused simultaneously. The present review study has aimed to illustrate the importance of DDR and autophagy in breast cancer according to the related studies and uncover the relation between DDR and autophagy and its significance in breast cancer therapy.
Assuntos
Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Dano ao DNA , Reparo do DNA , Transdução de Sinais , Antineoplásicos/farmacologia , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Autofagia , Proteína BRCA1/antagonistas & inibidores , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/fisiopatologia , DNA/metabolismo , Feminino , Humanos , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Poli(ADP-Ribose) Polimerases/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêuticoRESUMO
BACKGROUND: HLA-DMB proteins are important for intracellular microbial metabolism in order other major histocompatibility complex (MHC) molecules present peptides to lymphocytes. In addition, HLA-DMB alleles have been found linked to diseases in some ethnic groups and HLA-DMB molecules may be important to explain HLA disease association. OBJECTIVE: To detect HLA-DMB alleles profile in Amerindians for the first time and compare them to other populations. This will establish the bases to study HLA-DMB linkage to disease in Amerindians. METHOD: A group of 168 voluntary Amerindians have been typed for HLA-DMB alleles. They have been characterized both, by genetic and genealogical bases. Cloning and automated HLA-DMB DNA (exons 2, 3 and 4) sequencing have been performed for allele assignation. RESULTS: HLA-DMB*01:01:01 and HLA-DMB*01:03:01 show the highest frequencies. These have been compared to other World wide populations. HLA-DMB*01:03:01 is tightly associated to certain specific HLA-DRB1 alleles in Amerindians. CONCLUSION: The specific Amerindian HLA-DMB allele frequencies and their linkage disequilibrium with other MHC alleles may be crucial to determine HLA-DMB World wide variation, evolution and specific linkage to disease in Amerindians and other populations.
Assuntos
Alelos , Antígenos HLA-D/genética , Cadeias HLA-DRB1/genética , Indígenas Centro-Americanos , Indígenas Norte-Americanos , Indígenas Sul-Americanos , Desequilíbrio de Ligação , Evolução Molecular , Frequência do Gene , Genealogia e Heráldica , Predisposição Genética para Doença , Genética Populacional , Teste de Histocompatibilidade , Humanos , Polimorfismo GenéticoRESUMO
The hereditary disorder ataxia telangiectasia (A-T) is associated with striking cellular radiosensitivity that cannot be attributed to the characterized cell cycle checkpoint defects. By epistasis analysis, we show that ataxia telangiectasia mutated protein (ATM) and Artemis, the protein defective in patients with RS-SCID, function in a common double-strand break (DSB) repair pathway that also requires H2AX, 53BP1, Nbs1, Mre11, and DNA-PK. We show that radiation-induced Artemis hyperphosphorylation is ATM dependent. The DSB repair process requires Artemis nuclease activity and rejoins approximately 10% of radiation-induced DSBs. Our findings are consistent with a model in which ATM is required for Artemis-dependent processing of double-stranded ends with damaged termini. We demonstrate that Artemis is a downstream component of the ATM signaling pathway required uniquely for the DSB repair function but dispensable for ATM-dependent cell cycle checkpoint arrest. The significant radiosensitivity of Artemis-deficient cells demonstrates the importance of this component of DSB repair to survival.