RESUMO
PURPOSE: The aims of the present study were to better understand the role of Ku 80, which is involved in double-strand break repair in mammalian cells in the mechanism of radiation resistance and to verify the possibility of increasing cell radiosensitivity by targeted inhibition of Ku autoantigen 80 (Ku 80). MATERIALS AND METHODS: Western blot and electrophoretic mobility shift assay (EMSA) were performed on the human bladder carcinoma cell line RT112 (radioresistant) and on the human colorectal carcinoma cell line SW48 (radiosensitive) to assess the expression levels of DNA-dependent protein kinase (DNA-PK) components and the DNA-binding activity of the Ku 70/80 heterodimer after exposure to radiation, respectively. Ku 80 silencing was carried out with the use of small interfering RNA (siRNA). RESULTS: Greater differences in the DNA-binding activity of Ku 70/80 and Ku 80 phosphorylation level were observed in RT112 as compared to SW48 after X-ray treatment. There is no correlation between Ku expression and DNA-binding activity at lower doses. A significant increase in nuclear Ku 80 expression was observed one hour after the exposure, only at the higher doses, while the DNA-PK catalytic subunits (DNA-PKcs) and Ku 70 levels did not change significantly. Inhibition of Ku 80 expression by siRNA induced radiosensitivity in the RT112 cell line. CONCLUSIONS: Our data demonstrate that in a bladder tumour cell line up-regulation of Ku end-binding activity without any marked change in Ku expression underlie radiation resistance.
Assuntos
Antígenos Nucleares/metabolismo , Neoplasias Colorretais/metabolismo , Proteína Quinase Ativada por DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Tolerância a Radiação , Neoplasias da Bexiga Urinária/metabolismo , Linhagem Celular Tumoral , Relação Dose-Resposta à Radiação , Humanos , Autoantígeno Ku , Ligação Proteica/efeitos da radiação , Doses de Radiação , Estatística como AssuntoRESUMO
We studied whether DAP-kinase hypermethylation plays a role as a prognostic marker in patients with follicular lymphoma (FL). We found that DAP-kinase was frequently hypermethylated in bone marrow (BM) samples of 52 FL patients at diagnosis (71%) and identified patients with worse progression-free survival (p=0.06). In particular, patients with histologically proven BM infiltration and DAP-kinase hypermethylation had a poorer outcome (p=0.037). In a total of 170 BM samples obtained at diagnosis or during follow-up, DAP-kinase hypermethylation and the bcl2/IgH rearrangement gave concordant results in 67% of samples (48% both positive, 19% both negative). Both mrakers were independent predictors of the disease status (p<0.001).
Assuntos
Proteínas Reguladoras de Apoptose/genética , Medula Óssea/enzimologia , Proteínas Quinases Dependentes de Cálcio-Calmodulina/genética , Linfoma Folicular/enzimologia , Adulto , Idoso , Proteínas Reguladoras de Apoptose/análise , Biomarcadores Tumorais , Proteínas Quinases Dependentes de Cálcio-Calmodulina/análise , Metilação de DNA , Proteínas Quinases Associadas com Morte Celular , Feminino , Humanos , Linfoma Folicular/diagnóstico , Masculino , Pessoa de Meia-Idade , Prognóstico , Resultado do TratamentoRESUMO
Polymorphisms in carcinogen- and drug-metabolizing enzymes may increase the risk of acute myeloid leukemia (AML) and may influence prognosis. We report that the polymorphic variant of the cytochrome P450 CYP1A1*2A, present in 11.3% of patients, is an independent unfavorable prognostic factor for failure-free and overall survival in patients with AML.
Assuntos
Alelos , Citocromo P-450 CYP1A1/genética , Predisposição Genética para Doença , Leucemia Mieloide Aguda/genética , Doença Aguda , Citogenética , Intervalo Livre de Doença , Leucemia Mieloide Aguda/mortalidade , Polimorfismo Genético , Prognóstico , Indução de Remissão , Risco , Resultado do TratamentoRESUMO
The rising prevalence of obesity is a major global health problem. In severe obesity, bariatric surgery (BS) allows to obtain a significant weight loss and comorbidities improvement, among them one of the factors is the thrombotic risk. In this observational study, we measured indices of leukocyte activation in severely obese patients as markers of increased thrombotic risk in relation with serum markers of inflammation before and after BS. Frequency of polymorphonuclear neutrophil-platelet (PLT) and monocyte (MONO)-PLT aggregates as well as of tissue factor (TF) expressing MONOs was measured in the peripheral blood of 58 consecutive obese patients and 30 healthy controls. In 31 of the 58 obese patients, data obtained at the enrollment were compared with those obtained at 3, 6, and 12 months after BS. Compared with healthy controls, obese patients showed a higher frequency of polymorphonuclear leukocyte (PMNL)-PLT aggregates (7.47 ± 2.45 [6.82-8.11]% vs 5.85 ± 1.89 [5.14-6.55]%, P = 0.001), MONO-PLT aggregates (12.31 ± 7.33 [10.38-14.24]% vs 8.14 ± 2.22 [7.31-8.97]%, P < 0.001), and TF expressing MONOs (4.01 ± 2.11 [3.45-4.56]% vs 2.64 ± 1.65 [2.02-3.25]%, P = 0.002). PMNL-PLT and MONO-PLT aggregate frequency was positively correlated with TF expressing MONOs (R2 = 0.260, P = 0.049 and R2 = 0.318, P = 0.015, respectively). BS was performed in 31 patients and induced a significant reduction of the body mass index, and waist and hip circumferences. These effects were associated with a significant decrease of PMNL-PLT aggregates at 12 months (7.58 ± 2.27 [6.75-8.42]% vs 4.47 ± 1.11 [3.93-5.01]%, P < 0.001), and a reduction of TF expressing MONOs at 6 (3.82 ± 2.04 [3.07-4.57]% vs 1.60 ± 1.69 [0.30-2.90]%, P = 0.008) and 12 months (3.82 ± 2.04 [3.07-4.57]% vs 1.71 ± 0.54 [1.45-1.97]%, P = 0.001) after BS.These data suggest that leukocyte-PLT aggregate formation and MONO activation represent an important mechanism underlying the increased thrombotic risk of obese patients. We also show that BS is effective in normalizing these inflammatory indices.