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1.
Br J Haematol ; 203(2): 202-211, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37485564

RESUMO

Diffuse large B-cell lymphoma (DLBCL) patients with relapsed or refractory (RR) disease have poor outcomes with current salvage regimens. We conducted a phase 2 trial to analyse the safety and efficacy of adding lenalidomide to R-ESHAP (LR-ESHAP) in patients with RR DLBCL. Subjects received 3 cycles of lenalidomide 10 mg/day on days 1-14 of every 21-day cycle, in combination with R-ESHAP at standard doses. Responding patients underwent autologous stem-cell transplantation (ASCT). The primary endpoint was the overall response rate (ORR) after 3 cycles. Centralized cell-of-origin (COO) classification was performed. Forty-six patients were included. The ORR after LR-ESHAP was 67% (35% of patients achieved complete remission). Patients with primary refractory disease (n = 26) had significantly worse ORR than patients with non-refractory disease (54% vs. 85%, p = 0.031). No differences in response rates according to the COO were observed. Twenty-eight patients (61%) underwent ASCT. At a median follow-up of 41 months, the estimated 3-year PFS and OS were 42% and 48%, respectively. The most common grade ≥3 adverse events were thrombocytopenia (70% of patients), neutropenia (67%) and anaemia (35%). There were no treatment-related deaths during LR-ESHAP cycles. In conclusion, LR-ESHAP is a feasible salvage regimen with promising efficacy results for patients with RR DLBCL.


Assuntos
Linfoma Difuso de Grandes Células B , Linfoma não Hodgkin , Neutropenia , Trombocitopenia , Humanos , Lenalidomida/efeitos adversos , Linfoma não Hodgkin/tratamento farmacológico , Linfoma Difuso de Grandes Células B/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neutropenia/etiologia , Trombocitopenia/induzido quimicamente , Rituximab/uso terapêutico
2.
J Neurooncol ; 148(3): 545-554, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32524392

RESUMO

INTRODUCTION: To assess the management of immunocompetent patients with primary central nervous system lymphomas (PCNSL) in Spain. METHODS: Retrospective analysis of 327 immunocompetent patients with histologically confirmed PCNSL diagnosed between 2005 and 2014 in 27 Spanish hospitals. RESULTS: Median age was 64 years (range: 19-84; 33% ≥ 70 years), 54% were men, and 59% had a performance status (PS) ≥ 2 at diagnosis. Median delay to diagnosis was 47 days (IQR 24-81). Diagnostic delay > 47 days was associated with PS ≥ 2 (OR 1.99; 95% CI 1.13-3.50; p = 0.016) and treatment with corticosteroids (OR 2.47; 95% CI 1.14-5.40; p = 0.023), and it did not improve over the years. Patients treated with corticosteroids (62%) had a higher risk of additional biopsies (11.7% vs 4.0%, p = 0.04) but corticosteroids withdrawal before surgery did not reduce this risk and increased the diagnostic delay (64 vs 40 days, p = 0.04). Median overall survival (OS) was 8.9 months [95% CI 5.9-11.7] for the whole series, including 52 (16%) patients that were not treated, and 14.1 months (95%CI 7.7-20.5) for the 240 (73.4%) patients that received high-dose methotrexate (HD-MTX)-based chemotherapy. Median OS was shorter in patients ≥ 70 years (4.1 vs. 13.4 months; p < 0.0001). Multivariate analysis identified age ≥ 65 years, PS ≥ 2, no treatment, and cognitive/psychiatric symptoms at diagnosis as independent predictors of short survival. CONCLUSIONS: Corticosteroids withdrawal before surgery does not decrease the risk of a negative biopsy but delays diagnosis. In this community-based study, only 73.4% of patients could receive HD-MTX-based chemotherapy and OS remains poor, particularly in elderly patients ≥ 70 years.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Sistema Nervoso Central/mortalidade , Quimiorradioterapia/mortalidade , Irradiação Craniana/mortalidade , Diagnóstico Tardio/estatística & dados numéricos , Imunocompetência , Linfoma não Hodgkin/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Carmustina/administração & dosagem , Neoplasias do Sistema Nervoso Central/diagnóstico , Neoplasias do Sistema Nervoso Central/imunologia , Neoplasias do Sistema Nervoso Central/terapia , Citarabina/administração & dosagem , Feminino , Seguimentos , Humanos , Linfoma não Hodgkin/diagnóstico , Linfoma não Hodgkin/imunologia , Linfoma não Hodgkin/terapia , Masculino , Metotrexato/administração & dosagem , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida , Adulto Jovem
3.
Ann Hematol ; 99(7): 1627-1634, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32451707

RESUMO

There is no standard treatment for relapsed follicular lymphoma (FL). Although platinum-based combinations are one of the most used treatments, few data have been reported in this setting. Our aim was to analyse R-ESHAP efficacy in relapsed FL patients. We retrospectively analysed 80 FL patients treated with R-ESHAP in the first or successive relapses. Responding patients received a stem cell transplantation following R-ESHAP. Seventeen histologically transformed patients were included. Median age was 50 years. At R-ESHAP initiation, 85% of the patients were in an advanced stage, 28% had a bulky disease and 40% had increased LDH. There were no statistically significant differences between POD24 and non-POD24 patients in terms of response to R-ESHAP (ORR 72% vs. 93%, p = 0.109). When analyzing R-ESHAP efficacy according to the response to the immediately previous line, patients achieving CR or PR had better CR rates to R-ESHAP than those who did not respond (CR of 57% vs. 15%, respectively, p = 0.009), as well as differences in OS (7.2 vs. 1.4 years, p < 0.0001) and in PFS (2.1 vs. 0.3 years, p < 0.0001). R-ESHAP is an effective treatment in relapsed FL patients who respond to the previous line and has to be considered as an adequate alternative for some patients.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Linfoma Folicular/tratamento farmacológico , Linfoma Folicular/patologia , Rituximab/administração & dosagem , Terapia de Salvação/métodos , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Cisplatino/administração & dosagem , Cisplatino/efeitos adversos , Citarabina/administração & dosagem , Citarabina/efeitos adversos , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Etoposídeo/administração & dosagem , Etoposídeo/efeitos adversos , Feminino , Humanos , Linfoma Folicular/mortalidade , Masculino , Metilprednisolona/administração & dosagem , Metilprednisolona/efeitos adversos , Pessoa de Meia-Idade , Gradação de Tumores , Recidiva , Estudos Retrospectivos , Rituximab/efeitos adversos , Espanha/epidemiologia , Análise de Sobrevida , Falha de Tratamento , Resultado do Tratamento , Adulto Jovem
4.
Ann Hematol ; 97(12): 2417-2424, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30116871

RESUMO

Burkitt's monomorphic posttransplant lymphoproliferative disorder (B-PTLD) is an uncommon subtype of PTLD. Owing to the paucity of this complication, clinical characteristics and outcome has not been fully described. Clinical characteristics and outcomes of 20 patients diagnosed with B-PTLD from 10 transplant centers belonging to the GEL/TAMO group were reviewed. Median time from transplant to B-PTLD was 7.2 years. All the cases fulfill the morphologic and genetic criteria of B-PTLD, whereas Epstein-Barr virus (EBV) was detected in 70% of cases. Patients were treated with different chemotherapy combinations, and three patients received upfront rituximab monotherapy. The great majority of patients receiving CHOP-like regimens attained a complete response (CR) (73%), similar to that obtained with dose-intensive chemotherapy (83% CR). In contrast, patients receiving upfront rituximab monotherapy required subsequent chemotherapy. Two patients (10%) died during treatment due to infection. The median progression-free survival and overall survival (OS) were 16 months and 139 months, respectively. When analyzing variables predicting for OS, we found that patients with bone marrow involvement had an adverse prognosis, with a median OS of 6 months (p = 0.008). In conclusion, B-PTLD is an uncommon complication usually associated with EBV infection and with an aggressive clinical course, particularly in patients with bone marrow involvement. High-dose chemoimmunotherapy obtained similar responses to R-CHOP, suggesting that R-CHOP could be an adequate alternative for these patients. In contrast, rituximab monotherapy does not seem to be effective enough to control the disease.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Linfoma de Burkitt , Transplante de Células-Tronco Hematopoéticas , Transplante de Órgãos , Adulto , Idoso , Aloenxertos , Anticorpos Monoclonais Murinos/administração & dosagem , Linfoma de Burkitt/sangue , Linfoma de Burkitt/tratamento farmacológico , Linfoma de Burkitt/etiologia , Linfoma de Burkitt/mortalidade , Ciclofosfamida/administração & dosagem , Intervalo Livre de Doença , Doxorrubicina/administração & dosagem , Feminino , Herpesvirus Humano 4 , Humanos , Masculino , Pessoa de Meia-Idade , Prednisona/administração & dosagem , Rituximab , Taxa de Sobrevida , Vincristina/administração & dosagem
5.
Leukemia ; 32(3): 675-684, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-28804123

RESUMO

Genome studies of diffuse large B-cell lymphoma (DLBCL) have revealed a large number of somatic mutations and structural alterations. However, the clinical significance of these alterations is still not well defined. In this study, we have integrated the analysis of targeted next-generation sequencing of 106 genes and genomic copy number alterations (CNA) in 150 DLBCL. The clinically significant findings were validated in an independent cohort of 111 patients. Germinal center B-cell and activated B-cell DLBCL had a differential profile of mutations, altered pathogenic pathways and CNA. Mutations in genes of the NOTCH pathway and tumor suppressor genes (TP53/CDKN2A), but not individual genes, conferred an unfavorable prognosis, confirmed in the independent validation cohort. A gene expression profiling analysis showed that tumors with NOTCH pathway mutations had a significant modulation of downstream target genes, emphasizing the relevance of this pathway in DLBCL. An in silico drug discovery analysis recognized 69 (46%) cases carrying at least one genomic alteration considered a potential target of drug response according to early clinical trials or preclinical assays in DLBCL or other lymphomas. In conclusion, this study identifies relevant pathways and mutated genes in DLBCL and recognizes potential targets for new intervention strategies.


Assuntos
Variação Genética , Genômica , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/metabolismo , Transdução de Sinais , Adulto , Idoso , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Variações do Número de Cópias de DNA , Feminino , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Janus Quinases/metabolismo , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Estadiamento de Neoplasias , Receptores Notch/metabolismo , Fatores de Transcrição STAT/metabolismo , Transdução de Sinais/efeitos dos fármacos
6.
Ann Hematol ; 96(8): 1323-1330, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28536895

RESUMO

Guidelines recommend autologous stem cell transplantation (ASCT) consolidation in first complete or partial response after regimens including rituximab (R) and high-dose AraC (HDAC), but its use beyond that response is questioned. We present a retrospective analysis of 268 patients with MCL who received ASCT. With a median follow-up for survival patients of 54 months, progression-free survival and overall survival for the whole series were 38 and 74 months, respectively, and for patients transplanted in first CR 49 and 97 months, respectively. Patients without CR before transplant were analyzed separately, those who achieved CR after transplantation had better PFS (48 vs 0.03 months, p < 0.001) and OS (92 vs 16 months, p < 0.001) than the remaining. In univariate analysis, first CR at transplant (p = 0.01) and prior rituximab (p = 0.02) were the variables associated with PFS. For OS, the same variables resulted significant (p = 0.03 and p < 0.001, respectively). In multivariate analysis, only the status at transplant (first CR) remained significant. This retrospective study concludes that ASCT consolidation in first CR induces high survival rates. In other stages of disease, the need of ASCT as consolidation may be questioned.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Transplante de Células-Tronco Hematopoéticas/métodos , Linfoma de Célula do Manto/terapia , Adulto , Idoso , Citarabina/administração & dosagem , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Avaliação de Resultados em Cuidados de Saúde/métodos , Avaliação de Resultados em Cuidados de Saúde/estatística & dados numéricos , Modelos de Riscos Proporcionais , Indução de Remissão , Estudos Retrospectivos , Rituximab/administração & dosagem , Condicionamento Pré-Transplante , Transplante Autólogo , Adulto Jovem
7.
Ann Oncol ; 27(10): 1974, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27502706
8.
Ann Hematol ; 95(6): 893-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27025508

RESUMO

The dissemination in the central nervous system (CNS) is an uncommon but fatal complication occurring in patients with diffuse large B-cell lymphoma (DLBCL). Standard prophylaxis has been demonstrated to reduce CNS relapse and improve survival rates. Intrathecal (IT) liposomal cytarabine allows maintaining elevated drug levels in the cerebrospinal fluid for an extended period of time. Data on the efficacy and safety of liposomal cytarabine as CNS prophylaxis in patients with DLBCL are still insufficient. The objective of the present study was to evaluate the effectiveness and safety of the prophylaxis with IT liposomal cytarabine in prevention of CNS relapse in high-risk patients with DLBCL who were included in a trial of first line systemic therapy with 6 cycles of dose-dense R-CHOP every 14 days. Twenty-four (18.6 %) out of 129 patients were identified to have risk factors for CNS involvement, defined as follows: >30 % bone marrow infiltration, testes infiltration, retroperitoneal mass ≥10 cm, Waldeyer ring, or bulky cervical nodes involvement. Liposomal cytarabine (50 mg) was administered by lumbar puncture the first day of the 1st, 2nd, and 6th cycle of R-CHOP14 scheme. Among 70 IT infusions, grade 3-4 adverse events reported were headache (one patient) and nausea/vomiting (one patient). With a median follow-up of 40.1 months, no CNS involvement by DLBCL was observed in any patient. In conclusion, IT liposomal cytarabine is safe, feasible, and effective for CNS prophylaxis, causing few associated risks and little discomfort to patients with DLBCL.


Assuntos
Antimetabólitos Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Citarabina/administração & dosagem , Linfoma Difuso de Grandes Células B/diagnóstico , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Murinos/administração & dosagem , Ciclofosfamida/administração & dosagem , Doxorrubicina/administração & dosagem , Feminino , Seguimentos , Humanos , Injeções Espinhais , Linfoma Difuso de Grandes Células B/mortalidade , Masculino , Pessoa de Meia-Idade , Profilaxia Pós-Exposição/métodos , Prednisona/administração & dosagem , Estudos Prospectivos , Fatores de Risco , Rituximab , Taxa de Sobrevida , Vincristina/administração & dosagem , Adulto Jovem
9.
Oncogene ; 35(23): 2991-3003, 2016 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-26455323

RESUMO

SPROUTY-2 (SPRY2) is a modulator of tyrosine kinase receptor signaling with receptor- and cell type-dependent inhibitory or enhancing effects. Studies on the action of SPRY2 in major cancers are conflicting and its role remains unclear. Here we have dissected SPRY2 action in human colon cancer. Global transcriptomic analyses show that SPRY2 downregulates genes encoding tight junction proteins such as claudin-7 and occludin and other cell-to-cell and cell-to-matrix adhesion molecules in human SW480-ADH colon carcinoma cells. Moreover, SPRY2 represses LLGL2/HUGL2, PATJ1/INADL and ST14, main regulators of the polarized epithelial phenotype, and ESRP1, an epithelial-to-mesenchymal transition (EMT) inhibitor. A key action of SPRY2 is the upregulation of the major EMT inducer ZEB1, as these effects are reversed by ZEB1 knock-down by means of RNA interference. Consistently, we found an inverse correlation between the expression level of claudin-7 and those of SPRY2 and ZEB1 in human colon tumors. Mechanistically, ZEB1 upregulation by SPRY2 results from the combined induction of ETS1 transcription factor and the repression of microRNAs (miR-200 family, miR-150) that target ZEB1 RNA. Moreover, SPRY2 increased AKT activation by epidermal growth factor, whereas AKT and also Src inhibition reduced the induction of ZEB1. Altogether, these data suggest that AKT and Src are implicated in SPRY2 action. Collectively, these results show a tumorigenic role of SPRY2 in colon cancer that is based on the dysregulation of tight junction and epithelial polarity master genes via upregulation of ZEB1. The dissection of the mechanism of action of SPRY2 in colon cancer cells is important to understand the upregulation of this gene in a subset of patients with this neoplasia that have poor prognosis.


Assuntos
Neoplasias do Colo/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , MicroRNAs/metabolismo , Proteína Proto-Oncogênica c-ets-1/metabolismo , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismo , Adesão Celular/genética , Linhagem Celular Tumoral , Polaridade Celular/genética , Proliferação de Células/fisiologia , Neoplasias do Colo/genética , Neoplasias do Colo/patologia , Células Epiteliais , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética , MicroRNAs/genética , Fenótipo , Proteína Proto-Oncogênica c-ets-1/genética , Transdução de Sinais , Transfecção , Regulação para Cima , Homeobox 1 de Ligação a E-box em Dedo de Zinco/genética
10.
Bone Marrow Transplant ; 50(1): 34-9, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25222503

RESUMO

This retrospective study presents data from 105 consecutive multiple myeloma and lymphoma patients who had PB CD34+ cell counts <10/µL on day 4 of steady-state G-CSF mobilization for autologous hematopoietic cell transplantation. Our results confirm the capacity of plerixafor to improve mobilization outcomes in this clinical setting. In addition, they show that the effectiveness of plerixafor, compared with G-CSF only, translates to patients with very low (<3.5/µL) circulating CD34+ cell counts: overnight CD34+ cell count expansion (5.3- vs 1.7-fold), overall CD34+ cell yield (2.29 vs 0.15 × 10(6) CD34+ cells per kg) and patients yielding ⩾2 × 10(6) CD34+ cells per kg (63% vs 3%). Furthermore, our data also show that preemptive plerixafor is significantly more effective and more efficient than in remobilization: CD34+ cell yield in the first apheresis (3.28 vs 2.0 × 10(6) CD34+ cells per kg) and overall (3.73 vs 2.44 × 10(6) CD34+ cells per kg), patients yielding ⩾2 × 10(6) CD34+ cells per kg in the first apheresis (85% vs 44%) and overall (92% vs 64%), all this requiring less days and doses of plerixafor treatment (1.08 vs 1.48). These data would advocate using plerixafor as an early preemptive intervention based on day 4 circulating CD34+ counts, including very high-risk patients with very low circulating levels.


Assuntos
Fármacos Anti-HIV/administração & dosagem , Antígenos CD34/sangue , Mobilização de Células-Tronco Hematopoéticas , Compostos Heterocíclicos/administração & dosagem , Linfoma , Mieloma Múltiplo , Transplante de Células-Tronco de Sangue Periférico , Adulto , Idoso , Autoenxertos , Benzilaminas , Ciclamos , Feminino , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Humanos , Contagem de Leucócitos , Linfoma/sangue , Linfoma/terapia , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/sangue , Mieloma Múltiplo/terapia , Fatores de Risco
11.
Infection ; 41(2): 465-71, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23404684

RESUMO

PURPOSE: Influenza has a high morbidity and mortality rate and an increased risk of complications in vulnerable individuals. Children and adults with asthma have a high risk of complications, hospitalisation and even death. The objectives of this study were as follows: to compare influenza vaccination coverage in Spain in a population of asthmatics aged ≥ 16 years with an equivalent population of non-asthmatics; to identify the factors that influence vaccination coverage among patients with asthma; and to compare coverage during the period 2006/2007 with that of 2009/2010. METHODS: We used data from the 2009 European Health Survey (EHS), which included a population of 22,188 individuals (≥ 16 years of age), of whom 1,669 [7.5 %; 95 % confidence interval (CI), 7.13-7.98] had asthma. The dependent variable was the answer (yes/no) to a question asking whether or not the interviewed person had been vaccinated against seasonal (not pandemic) influenza in the previous season. As independent variables, we analysed socio-demographic characteristics, health-related variables and the use of health care services. RESULTS: Vaccination coverage was 35.2 % (95 % CI, 32.5-37.9) among asthmatics and 22.1 % (95 % CI, 21.4-22.7) among non-asthmatics (p < 0.001). The probability of being vaccinated is almost twice as high for asthmatics as it is for non-asthmatics [odds ratio (OR), 1.92; 95 % CI, 1.69-2.17]. Among asthmatics, vaccination coverage increased with age, worse self-rated health status and not smoking. No significant change in coverage was observed between the study periods. CONCLUSIONS: Seasonal influenza vaccination coverage among Spanish asthmatics is lower than desired and has not improved in recent years. Urgent strategies are necessary in order to increase vaccination coverage among asthmatics.


Assuntos
Asma/virologia , Vacinas contra Influenza/administração & dosagem , Influenza Humana/prevenção & controle , Vacinação/estatística & dados numéricos , Adolescente , Adulto , Fatores Etários , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Fatores Socioeconômicos , Espanha , Adulto Jovem
12.
Biophys J ; 98(11): 2591-600, 2010 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-20513403

RESUMO

F(1)-ATPase is a rotatory molecular motor fueled by ATP nucleotides. Different loads can be attached to the motor axis to show that it rotates in main discrete steps of 120 degrees with substeps of approximately 80 degrees and 40 degrees . Experimental data show the dependence on the mean rotational velocity omega with respect to the external control parameters: the nucleotide concentration [ATP] and the friction of the load gamma(L). In this work we present a theoretical analysis of the experimental data whose main results are: 1), A derivation of a simple analytical formula for omega([ATP], gamma(L)) that compares favorably with experiments; 2), The introduction of a two-state flashing ratchet model that exhibits experimental phenomenology of a greater specificity than has been, to our knowledge, previously available; 3), The derivation of an argument to obtain the values of the substep sizes; 4), An analysis of the energy constraints of the model; and 5), The theoretical analysis of the coupling ratio between the ATP consumed and the success of a forward step. We also discuss the compatibility of our approach with recent experimental observations.


Assuntos
Modelos Químicos , ATPases Translocadoras de Prótons/química , Trifosfato de Adenosina/química , Algoritmos , Bactérias/química , Bactérias/enzimologia , Proteínas de Bactérias/química , Simulação por Computador , Elasticidade , Fricção , Movimento (Física) , Rotação , Processos Estocásticos , Temperatura , Fatores de Tempo
13.
J Chem Phys ; 131(1): 015104, 2009 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-19586125

RESUMO

Kinesin-1 motion on a microtubule (MT) is still receiving a great attention due to its relevance in understanding molecular motion triggered by adenosine triphosphate (ATP) hydrolysis. Recent experimental data on kinesin-tubulin-nucleotide interactions have clarified some of the conformational details involved in the hydrolysis process [T. Mori et al., Nature (London) 450, 750 (2007)]. Specifically, fluorescence resonance energy transfer was used to measure the affinity of motor domains to tubulin heterodimers. Our work is directly devoted to understand and reproduce the main output of these experiments as well as to go beyond and give a global dynamical picture of the whole hydrolysis cycle. We predict that phosphate groups have the ability to confine to the tubulin domains in order to explain the delay between ATP hydrolysis and head detaching, which seems crucial for the achievement of processivity. In our approach me make use of chemical kinetics complemented with stochastic molecular simulations of the elements involved.


Assuntos
Cinesinas/química , Modelos Biológicos , Nucleotídeos/química , Difosfato de Adenosina/química , Hidrólise , Conformação Molecular , Tubulina (Proteína)/química
14.
Eur Phys J E Soft Matter ; 29(3): 329-36, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19575251

RESUMO

We study channel transport across biomembranes. We propose a model that couples the diffusive dynamics with the gating process via a two-state ratchet mechanism. This gating process is governed by ATP binding and hydrolysis, and the process exhibits Michaelis-Menten enzymatic kinetics. The particle flow and permeability of the channel are studied both analytically and numerically in the steady-state regime, while working between fixed concentrations. The results are compared with simpler models and with experimental data. Also, a simulation framework, that allows high flexibility in parameter exploration, is introduced.


Assuntos
Trifosfato de Adenosina/metabolismo , Membrana Celular/metabolismo , Ativação do Canal Iônico , Canais Iônicos/metabolismo , Modelos Biológicos , Permeabilidade da Membrana Celular , Cloretos/metabolismo , Hidrólise
15.
Oncogene ; 27(32): 4467-77, 2008 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-18408752

RESUMO

Aberrant activation of the Wnt/beta-catenin signaling pathway is a hallmark of colon cancer. We show that the Wnt antagonist DICKKOPF-4 (DKK-4) gene is repressed by 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) in human colon cancer cells. This effect correlated with the inhibition of the DKK-4 promoter. Chromatin immunoprecipitation assays revealed that 1,25(OH)2D3 induces early and transient binding of the vitamin D receptor (VDR) and the SMRT corepressor to the region adjacent to the transcription start site of DKK-4. Additionally, we demonstrate that the DKK-4 gene is a new downstream target of TCF/beta-catenin. Remarkably, expression of DKK-4 messenger RNA (mRNA) was not detected in a series of 29 human normal (N) colon biopsies but expression was upregulated in all the matched tumour (T) tissues. An inverse correlation existed between the expression of DKK-4 and VDR RNA in the Ts. Ectopic DKK-4 expression increased the migration and invasion properties of colon cancer cells and conditioned media (CM) from DKK-4-expressing cells enhanced the capacity to migrate and form capillary-like tubules of human primary microvascular endothelial cells. In conclusion, DKK-4 is upregulated in colon cancer and is associated with the acquisition of malignant properties by neoplastic cells. DKK-4 downregulation is a novel effect of 1,25(OH)2D3 that may contribute to its anticancer action.


Assuntos
Calcitriol/farmacologia , Neoplasias do Colo/patologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Neovascularização Patológica/etiologia , Fatores de Transcrição TCF/fisiologia , beta Catenina/fisiologia , Linhagem Celular Tumoral , Neoplasias do Colo/irrigação sanguínea , Neoplasias do Colo/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/fisiologia , Invasividade Neoplásica , Regiões Promotoras Genéticas , Receptores de Calcitriol/metabolismo
16.
Oncogene ; 25(29): 4116-21, 2006 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-16491118

RESUMO

Colorectal cancer is a major cause of cancer death worldwide. A number of key oncogenes and tumor suppressor genes have been proposed to drive progression from healthy colonic epithelia to malignant tumors, including members of the Wnt/beta-catenin pathway. Recently, CpG island promoter hypermethylation was shown to cause inactivation of two extracellular Wnt inhibitors in colon cancer: secreted frizzled-related proteins (sFRPs) and Wnt inhibitory factor-1 (WIF-1). Here, we show for the first time that another extracellular Wnt inhibitor, the DICKKOPF-1 (DKK-1) gene, is transcriptionally silenced by CpG island promoter hypermethylation in colon cancer cell lines (n=9), whereas treatment with the DNA-demethylating agent 5-aza-2-deoxycytidine restored DKK-1 expression. Restoration of DKK-1 function in non-expressing cells bearing a truncated APC (Adenomatous Polyposis Coli) gene had no effect on beta-catenin/T-cell factor-dependent transcription, but induced tumor suppressor-like features such as reduced colony formation density and tumor growth inhibition in nude mice. These results suggest additional functions for DKK-1 other than inhibiting canonical Wnt signaling. In primary colorectal tumors, DKK-1 was found hypermethylated in 17% (nine of 54) of cases. Furthermore, while for both SFRP-1 and WIF-1 methylation-associated silencing occurred across the whole spectrum of colorectal tumorigenesis, DKK-1 promoter was selectively hypermethylated in advanced colorectal neoplasms (Duke's C and D tumors).


Assuntos
Transformação Celular Neoplásica/genética , Neoplasias Colorretais/genética , Epigênese Genética , Genes Supressores de Tumor , Peptídeos e Proteínas de Sinalização Intercelular/genética , Proteínas Wnt/genética , Proteínas Adaptadoras de Transdução de Sinal , Proteína da Polipose Adenomatosa do Colo/genética , Proteína da Polipose Adenomatosa do Colo/metabolismo , Animais , Antimetabólitos Antineoplásicos/farmacologia , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Colo/metabolismo , Colo/patologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Ilhas de CpG/genética , Metilação de DNA , Decitabina , Epitélio/metabolismo , Epitélio/patologia , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Camundongos , Camundongos Nus , Transplante de Neoplasias , Regiões Promotoras Genéticas/genética , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transplante Heterólogo , Proteínas Wnt/antagonistas & inibidores , Proteínas Wnt/metabolismo
17.
Phys Rev E Stat Nonlin Soft Matter Phys ; 72(3 Pt 1): 031918, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16241493

RESUMO

We present a model that allows for the derivation of the experimentally accessible observables: spatial steps, mean velocity, stall force, useful power, efficiency and randomness, etc. as a function of the [adenosine triphosphate] concentration and an external load F. The model presents a minimum of adjustable parameters and the theoretical predictions compare well with the available experimental results.


Assuntos
Cinesinas/química , Cinesinas/fisiologia , Modelos Biológicos , Modelos Moleculares , Proteínas Motores Moleculares/química , Proteínas Motores Moleculares/fisiologia , Trifosfato de Adenosina/química , Trifosfato de Adenosina/fisiologia , Simulação por Computador , Modelos Químicos , Movimento/fisiologia
18.
J Cell Biol ; 154(2): 369-87, 2001 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-11470825

RESUMO

The beta-catenin signaling pathway is deregulated in nearly all colon cancers. Nonhypercalcemic vitamin D3 (1alpha,25-dehydroxyvitamin D(3)) analogues are candidate drugs to treat this neoplasia. We show that these compounds promote the differentiation of human colon carcinoma SW480 cells expressing vitamin D receptors (VDRs) (SW480-ADH) but not that of a malignant subline (SW480-R) or metastasic derivative (SW620) cells lacking VDR. 1alpha,25(OH)2D(3) induced the expression of E-cadherin and other adhesion proteins (occludin, Zonula occludens [ZO]-1, ZO-2, vinculin) and promoted the translocation of beta-catenin, plakoglobin, and ZO-1 from the nucleus to the plasma membrane. Ligand-activated VDR competed with T cell transcription factor (TCF)-4 for beta-catenin binding. Accordingly, 1alpha,25(OH)2D(3) repressed beta-catenin-TCF-4 transcriptional activity. Moreover, VDR activity was enhanced by ectopic beta-catenin and reduced by TCF-4. Also, 1alpha,25(OH)2D(3) inhibited expression of beta-catenin-TCF-4-responsive genes, c-myc, peroxisome proliferator-activated receptor delta, Tcf-1, and CD44, whereas it induced expression of ZO-1. Our results show that 1alpha,25(OH)2D(3) induces E-cadherin and modulates beta-catenin-TCF-4 target genes in a manner opposite to that of beta-catenin, promoting the differentiation of colon carcinoma cells.


Assuntos
Adenocarcinoma/metabolismo , Caderinas/biossíntese , Calcitriol/análogos & derivados , Diferenciação Celular/efeitos dos fármacos , Colecalciferol/farmacologia , Neoplasias do Colo/metabolismo , Proteínas do Citoesqueleto/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Transativadores , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Adenocarcinoma/patologia , Antineoplásicos , Calcitriol/farmacologia , Moléculas de Adesão Celular/metabolismo , Membrana Celular/metabolismo , Neoplasias do Colo/patologia , Proteínas do Citoesqueleto/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Ligantes , Substâncias Macromoleculares , Fenótipo , Ligação Proteica/efeitos dos fármacos , RNA Mensageiro/metabolismo , Receptores de Calcitriol/metabolismo , Fatores de Transcrição TCF , Proteína 2 Semelhante ao Fator 7 de Transcrição , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transfecção , Células Tumorais Cultivadas , Vitamina D/análogos & derivados , Vitamina D/farmacologia , beta Catenina
19.
J Cell Biol ; 150(5): 1199-208, 2000 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-10974006

RESUMO

The immunosuppressive and antiinflammatory actions of glucocorticoid hormones are mediated by their transrepression of activating protein-1 (AP-1) and nuclear factor-kappa B (NFkappaB) transcription factors. Inhibition of the c-Jun NH(2)-terminal kinase (JNK) signaling pathway, the main mediator of AP-1 activation, has been described in extracts of hormone-treated cells. Here, we show by confocal laser microscopy, enzymatic assays, and immunoblotting that the synthetic glucocorticoid dexamethasone inhibited tumor necrosis factor alpha (TNF-alpha)-induced phosphorylation and activation of JNK in the cytoplasm and nucleus of intact HeLa cells. As a result, c-Jun NH(2)-terminal domain phosphorylation and induction were impaired. Dexamethasone did not block the TNF-alpha-induced JNK nuclear translocation, but rather induced, per se, nuclear accumulation of the enzyme. Consistently with previous findings, a glucocorticoid receptor mutant (GRdim), which is deficient in dimerization, DNA binding, and transactivation, but retains AP-1 transrepressing activity, was as efficient as wild-type GR in mediating the same effects of dexamethasone on JNK in transfected Cos-7 cells. Our results show that glucocorticoids antagonize the TNF-alpha-induced activation of AP-1 by causing the accumulation of inactive JNK without affecting its subcellular distribution.


Assuntos
Núcleo Celular/metabolismo , Dexametasona/farmacologia , Glucocorticoides/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fator de Transcrição AP-1/metabolismo , Animais , Células COS , Fracionamento Celular , Núcleo Celular/efeitos dos fármacos , Citosol/efeitos dos fármacos , Citosol/metabolismo , Ativação Enzimática , Células HeLa , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno , Cinética , Proteínas Quinases Ativadas por Mitógeno/efeitos dos fármacos , Fosforilação , Proteínas Recombinantes/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fator de Transcrição AP-1/antagonistas & inibidores , Transfecção , Fator de Necrose Tumoral alfa/farmacologia
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