Assuntos
Animais , Humanos , Camundongos , Antineoplásicos/uso terapêutico , Proteínas de Neoplasias/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Poli(ADP-Ribose) Polimerases/antagonistas & inibidores , Antineoplásicos/farmacologia , Ensaios Clínicos como Assunto , Reparo do DNA/efeitos dos fármacos , DNA de Neoplasias/efeitos dos fármacos , DNA de Neoplasias/metabolismo , Dacarbazina/administração & dosagem , Dacarbazina/análogos & derivados , Dacarbazina/farmacologia , Sistemas de Liberação de Medicamentos , Desenho de Fármacos , Resistencia a Medicamentos Antineoplásicos , Ensaios de Seleção de Medicamentos Antitumorais , Sinergismo Farmacológico , Camundongos Knockout , Proteínas de Neoplasias/fisiologia , Neoplasias/enzimologia , Poli(ADP-Ribose) Polimerases/química , Poli(ADP-Ribose) Polimerases/deficiência , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/fisiologia , Tolerância a Radiação/efeitos dos fármacosRESUMO
Numerous types of cells have been shown to undergo apoptosis when exposed to oxidant agent such as hydrogen peroxide. In order to understand the functional relationship between the anti- and pro-apoptotic regulatory proteins in the cells under oxidant stress, we have studied the level of expression of apoptosis regulatory proteins, bcl-2 and bax, in human leukemia HL-60 cells. The exposure of HL-60 cells to different concentrations of H2O2 for 6 h resulted in a typical apoptosis of the cells as characterized by flow cytometry, cell cycle analysis, and DNA fragmantation. There was a block in G1 to S transition and apoptotic cells were mainly derived from S and G2 cells. Kinetic study demonstrated that the levels of both bcl-2-mRNA and -protein expression were decreased with the progression of cellular apoptosis whereas the level of bax-mRNA was unchanged but the expressed bax-protein was not detectable. Cycloheximide, a nonspecific translation inhibitor, did not prevent the hydrogen peroxide-mediated apoptosis in HL-60 cells. These results suggest that the regulation of bcl-2, but not of bax are important factor in the oxidative stress-induced apoptosis in HL-60 cells.
Assuntos
Humanos , Apoptose/efeitos dos fármacos , Western Blotting , Cicloeximida/farmacologia , Fragmentação do DNA , DNA de Neoplasias/metabolismo , DNA de Neoplasias/genética , DNA de Neoplasias/efeitos dos fármacos , Relação Dose-Resposta a Droga , Citometria de Fluxo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HL-60 , Peróxido de Hidrogênio/farmacologia , Oxidantes/farmacologia , Inibidores da Síntese de Proteínas/farmacologia , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/efeitos dos fármacosRESUMO
Limited digestion (2 min) of Sarcoma-180 nuclei by DNase-II released two nonhistone proteins from the hypersensitive sites of chromatin. The apparent molecular weights of these two proteins were 34 and 21 kDa. These proteins showed a moderate but specific inhibition in in vitro cell free transcription assay with native chromatin as template as opposed to no effect on native DNA transcription.
Assuntos
Animais , Cromatina/metabolismo , DNA de Neoplasias/metabolismo , Proteínas de Ligação a DNA/isolamento & purificação , Endodesoxirribonucleases/metabolismo , Masculino , Camundongos , Ratos , Sarcoma 180/genética , Transcrição Gênica/fisiologiaRESUMO
The cytotoxic effects of acetylated oil of Semecarpus anacardium nuts on the cells of P388 lymphocytic leukemia were tested in vitro. The product was tested at the concentrations ranging from 15-75 micrograms/ml. The cell kill was observed as early as three hr after the treatment. The effects of acetylated oil on the biosynthesis of DNA, RNA and protein using labelled thymidine, uridine and leucine respectively showed that the product inhibited the biosynthesis of all the three. This was indicated by the inhibition of the incorporation of their precursors. The uptake of 3H-thymidine was inhibited 15 min after treatment; while that of 3H-uridine and 14C-leucine took 30 and 45 min respectively. Since the S. anacardium oil was unstable due to air-oxidation, the studies were confined to its acetylated product.