RESUMO
INTRODUCTION: Multiple myeloma (MM) development involves a series of genetic abnormalities and changes in the bone marrow (BM) microenvironment, favoring the growth of the tumor and failure of local immune control. T regulatory (Treg) cells play an important role in dampening anti-tumor immune responses while T-helper-17 (Th17) cells seem to be critical for the eradication of malignant cells. The aim of our study was to characterize the expression of Treg- and Th17-related genes in total myeloma BM samples to assess their role as biomarkers, prognostic factors, and possible therapeutic targets in this incurable disease. METHODS: Expression of markers for Treg (FOXP3, CTLA4) and Th17 cells (RORγt) was determined by quantitative real-time PCR in BM aspirates of 46 MM patients, four patients with monoclonal gammopathy of undetermined significance, five solitary plasmacytomas, and five healthy BM donors. Gene expression was evaluated regarding an influence on the patients' overall survival (OS). RESULTS: FOXP3 and CTLA4 presented a sixfold (p = 0.02) and 30-fold higher expression (p = 0.03), respectively, in MM patients than in controls. RORγt expression was similar in MM patients and controls. Median OS of MM patients was 16.8 (range 4.5-29.1) months, and international staging system was the only independent prognostic factor for patients survival. CONCLUSIONS: Overexpression of FOXP3 and CTLA4 in total BM samples suggests a local accumulation of immunosuppressive Tregs, the MM tumor environment, possibly dampening anti-tumor host immune responses. Therapeutic approaches targeting Treg cells and restoring local anti-tumor immunity may provide new treatment strategies for this incurable malignancy.
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Medula Óssea/metabolismo , Antígeno CTLA-4/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Mieloma Múltiplo/metabolismo , Linfócitos T Reguladores/citologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Células da Medula Óssea/citologia , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Terapia de Imunossupressão , Masculino , Pessoa de Meia-Idade , Gamopatia Monoclonal de Significância Indeterminada/genética , Mieloma Múltiplo/mortalidade , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Plasmocitoma/genética , Plasmocitoma/metabolismo , Sindecana-1/metabolismo , Células Th17/citologia , Resultado do TratamentoRESUMO
BACKGROUND: Sequential population-based household serosurveys of SARS-CoV-2 covering the COVID-19 pre- and post-vaccination periods are scarce in Brazil. This study investigated seropositivity trends in the municipality of São Paulo. METHODS: We conducted seven cross-sectional surveys of adult population-representative samples between June 2020 and April 2022. The study design included probabilistic sampling, test for SARS-CoV-2 antibodies using the Roche Elecsys anti-nucleocapsid assay, and statistical adjustments for population demographics and non-response. The weighted seroprevalences with 95% confidence intervals (CI) were estimated by sex, age group, race, schooling, and mean income study strata. Time trends in seropositivity were assessed using the Joinpoint model. We compared infection-induced seroprevalences with COVID-19 reported cases in the pre-vaccination period. RESULTS: The study sample comprised 8,134 adults. The overall SARS-CoV-2 seroprevalence increased from 11.4% (95%CI: 9.2-13.6) in June 2020 to 24.9% (95%CI: 21.0-28.7) in January 2021; from 38.1% (95%CI: 34.3-41.9) in April 2021 to 77.7% (95%CI: 74.4-81.0) in April 2022. The prevalence over time was higher in the subgroup 18-39 years old than in the older groups from Survey 3 onwards. The self-declared Black or mixed (Pardo) group showed a higher prevalence in all surveys compared to the White group. Monthly prevalence rose steeply from January 2021 onwards, particularly among those aged 60 years or older. The infection-to-case ratios ranged from 8.9 in June 2020 to 4.3 in January 2021. CONCLUSIONS: The overall seroprevalence rose significantly over time and with age and race subgroup variations. Increases in the 60 years or older age and the White groups were faster than in younger ages and Black or mixed (Pardo) race groups in the post-vaccination period. Our data may add to the understanding of the complex and changing population dynamics of the SARS-CoV-2 infection, including the impact of vaccination strategies and the modelling of future epidemiological scenarios.
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Anticorpos Antivirais , COVID-19 , SARS-CoV-2 , Humanos , Brasil/epidemiologia , Adulto , Masculino , COVID-19/epidemiologia , COVID-19/imunologia , Estudos Soroepidemiológicos , Pessoa de Meia-Idade , Feminino , SARS-CoV-2/imunologia , Estudos Transversais , Adulto Jovem , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Idoso , AdolescenteAssuntos
Células Gigantes , Micronúcleos com Defeito Cromossômico , Mitose , Síndromes Mielodisplásicas , Eritrócitos/metabolismo , Eritrócitos/patologia , Células Gigantes/metabolismo , Células Gigantes/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/sangue , Síndromes Mielodisplásicas/diagnóstico , Síndromes Mielodisplásicas/patologiaRESUMO
The diagnosis and management of graft-versus-host disease (GVHD) have remained important challenges in allogeneic stem cell transplantation (allo-SCT). Novel diagnostic methods and therapeutic interventions are needed to further improve on patient outcomes. Extracellular vesicles (EV) are microvesicles formed by the inversion of the phospholipid bilayer of different cellular subtypes and have been described as biomarkers of cellular damage, activation, and intercellular signaling in numerous clinical scenarios. We studied the association between the levels of EV and the incidence of acute GVHD (aGVHD). Forty patients undergoing allo-SCT for hematological malignancies had their plasma collected at neutrophil engraftment. Using flow cytometry combined with fluorescent beads, the total circulating EV count (TEV) was established with annexin V positivity; CD61 positivity was used for platelet-derived EV (PEV), and CD235 positivity, for erythrocyte-derived EV (EryEV). TEV counts greater than 516/µL were associated with a higher cumulative incidence (CI) of grade II to IV aGVHD (54% vs. 21%; p = 0.02), as were EryEV counts above 357 /µL (CI of aGVHD: 59% vs. 26%; p = 0.04). In patients who are exposed to reduced intensity conditioning (RIC), stronger associations of both high TEV and EryEV counts with aGVHD were observed (77% vs. 22%; p = 0.003 and 89% vs. 27%; p = 0.002, respectively). PEV levels were not associated with the risk of aGVHD. Our data suggest that the measurement of cell-derived EV at engraftment can be used as a preemptive biomarker for acute GVHD.
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Vesículas Extracelulares , Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Humanos , Transplante Homólogo , Doença Enxerto-Hospedeiro/diagnóstico , Doença Enxerto-Hospedeiro/etiologia , Doença Enxerto-Hospedeiro/epidemiologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Biomarcadores , Doença Aguda , Condicionamento Pré-Transplante/métodosAssuntos
Células Precursoras de Granulócitos/patologia , Leucemia Mielomonocítica Aguda/sangue , Idoso , Deleção Cromossômica , Transtornos Cromossômicos/sangue , Transtornos Cromossômicos/genética , Transtornos Cromossômicos/patologia , Cromossomos Humanos Par 13/genética , Humanos , Leucemia Mielomonocítica Aguda/genética , Leucemia Mielomonocítica Aguda/patologia , MasculinoRESUMO
ABSTRACT: While the new Coronavirus Disease 2019 (COVID-19) pandemic rapidly spread across the world, South America was reached later in relation to Asia, Europe and the United States of America (USA). Brazil concentrates now the largest number of cases in the continent and, as the disease speedily progressed throughout the country, prompt and challenging operational strategies had to be taken by institutions caring for COVID-19 and non-COVID-19 patients in order to assure optimal workflows, triage, and management. Although hospitals in the USA, Europe and Asia have shared their experience on this subject, little has been discussed about such strategies in South America or by the perspective of outpatient centers, which are paramount in the radiology field. This article shares the guidelines adopted early in the pandemic by a nationwide outpatient healthcare center composed by a network of more than 200 patient service centers and nearly 2,000 radiologists in Brazil, discussing operational and patient management strategies, staff protection, changes adopted in the fellowship program, and the effectiveness of such measures.
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Assistência Ambulatorial , COVID-19 , Gestão de Mudança , Defesa Civil , Procedimentos Clínicos , Planejamento Estratégico , Tecnologia Radiológica , Assistência Ambulatorial/métodos , Assistência Ambulatorial/organização & administração , Assistência Ambulatorial/estatística & dados numéricos , Brasil/epidemiologia , COVID-19/diagnóstico , COVID-19/epidemiologia , COVID-19/prevenção & controle , Defesa Civil/organização & administração , Defesa Civil/estatística & dados numéricos , Procedimentos Clínicos/organização & administração , Procedimentos Clínicos/tendências , Humanos , Inovação Organizacional , Guias de Prática Clínica como Assunto , SARS-CoV-2 , Planejamento Estratégico/normas , Planejamento Estratégico/estatística & dados numéricos , Tecnologia Radiológica/métodos , Tecnologia Radiológica/organização & administração , Tecnologia Radiológica/estatística & dados numéricosRESUMO
BACKGROUND: São Paulo city has been one of the regions most affected by the COVID-19 pandemic in Brazil. Frequent asymptomatic and oligosymptomatic infections and poor access to diagnostic tests make serosurveys crucial to monitor the magnitude of the epidemic and to inform public health policies, such as vaccination plans. OBJECTIVES: To estimate, early in the epidemic, the seroprevalence of antibodies to SARS-CoV-2 in adults living in the six most affected districts in São Paulo city, and to assess potential associated risk factors. METHODS: This was a cross-sectional population-based survey of 1,152 households randomly selected from 72 census tracts. During the period May 4-12, 2020, 463 participants completed a questionnaire on sociodemographic characteristics and history of symptoms in the past two weeks, and provided a blood sample. Prevalence of SARS-CoV-2 antibodies was the outcome of interest and was estimated based on results of two immunoassays, Maglumi SARS-CoV-2 chemiluminescence assay Immunoglobulin (Ig) M (IgM) and IgG, and Roche electrochemiluminescence assay total Ig. Serum samples reactive to either assay were considered positive. RESULTS: Weighted overall seroprevalence was 6% (95%CI 3.9-8.3%). No association was observed between seropositivity and sex, age group or education level. Participants who reported black and brown skin color showed a 2.7 fold higher prevalence than people with white skin (p = 0.007). Among the 30 seropositive individuals, 14 (46.6%) reported no COVID-19 compatible symptoms in the past two weeks. CONCLUSION: This study represents the first assessment of SARS-CoV-2 seroprevalence in the city of São Paulo and 6% is the baseline estimate of a series of population-based seroprevalence surveys. Serological screening using sound serological assays is the key tool to monitoring temporal and geographic changes in the spread of the virus through an important epicenter of the COVID-19 pandemic in Brazil. Ultimately, it may inform prevention and control efforts.
Assuntos
COVID-19 , SARS-CoV-2 , Adulto , Anticorpos Antivirais , Brasil/epidemiologia , Estudos Transversais , Humanos , Imunoglobulina G , Pandemias , Estudos SoroepidemiológicosRESUMO
A growing body of evidence suggests a key role of tumor microenvironment, especially for bone marrow mesenchymal stem cells (MSC), in the maintenance and progression of multiple myeloma (MM), through direct and indirect interactions with tumor plasma cells. Thus, this study aimed to investigate the gene expression and functional alterations of MSC from MM patients (MM-MSC) in comparison with their normal counterparts from normal donors (ND-MSC). Gene expression analysis (Affymetrix) was performed in MM-MSC and ND-MSC after in vitro expansion. To validate these findings, some genes were selected to be evaluated by quantitative real time PCR (RT-qPCR), and also functional in vitro analyses were performed. We demonstrated that MM-MSC have a distinct gene expression profile than ND-MSC, with 485 differentially expressed genes (DEG) - 280 upregulated and 205 downregulated. Bioinformatics analyses revealed that the main enriched functions among downregulated DEG were related to cell cycle progression, immune response activation and bone metabolism. Four genes were validated by qPCR - ZNF521 and SEMA3A, which are involved in bone metabolism, and HLA-DRA and CHIRL1, which are implicated in the activation of immune response. Taken together, our results suggest that MM-MSC have constitutive abnormalities that remain present even in the absence of tumors cells. The alterations found in cell cycle progression, immune system activation, and osteoblastogenesis suggest, respectively, that MM-MSC are permanently dependent of tumor cells, might contribute to immune evasion and play an essential role in bone lesions frequently found in MM patients.
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Osso e Ossos/metabolismo , Células-Tronco Mesenquimais/metabolismo , Mieloma Múltiplo/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Células da Medula Óssea/metabolismo , Divisão Celular/genética , Divisão Celular/fisiologia , Feminino , Perfilação da Expressão Gênica/métodos , Cadeias alfa de HLA-DR/genética , Cadeias alfa de HLA-DR/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Microambiente Tumoral/genética , Microambiente Tumoral/fisiologiaRESUMO
ABSTRACT Background: São Paulo city has been one of the regions most affected by the COVID-19 pandemic in Brazil. Frequent asymptomatic and oligosymptomatic infections and poor access to diagnostic tests make serosurveys crucial to monitor the magnitude of the epidemic and to inform public health policies, such as vaccination plans. Objectives: To estimate, early in the epidemic, the seroprevalence of antibodies to SARS-CoV-2 in adults living in the six most affected districts in São Paulo city, and to assess potential associated risk factors. Methods: This was a cross-sectional population-based survey of 1,152 households randomly selected from 72 census tracts. During the period May 4-12, 2020, 463 participants completed a questionnaire on sociodemographic characteristics and history of symptoms in the past two weeks, and provided a blood sample. Prevalence of SARS-CoV-2 antibodies was the outcome of interest and was estimated based on results of two immunoassays, Maglumi SARS-CoV-2 chemiluminescence assay Immunoglobulin (Ig) M (IgM) and IgG, and Roche electrochemiluminescence assay total Ig. Serum samples reactive to either assay were considered positive. Results: Weighted overall seroprevalence was 6% (95%CI 3.9-8.3%). No association was observed between seropositivity and sex, age group or education level. Participants who reported black and brown skin color showed a 2.7 fold higher prevalence than people with white skin (p = 0.007). Among the 30 seropositive individuals, 14 (46.6%) reported no COVID-19 compatible symptoms in the past two weeks. Conclusion: This study represents the first assessment of SARS-CoV-2 seroprevalence in the city of São Paulo and 6% is the baseline estimate of a series of population-based seroprevalence surveys. Serological screening using sound serological assays is the key tool to monitoring temporal and geographic changes in the spread of the virus through an important epicenter of the COVID-19 pandemic in Brazil. Ultimately, it may inform prevention and control efforts.
Assuntos
Humanos , Adulto , SARS-CoV-2 , COVID-19 , Brasil/epidemiologia , Imunoglobulina G , Estudos Soroepidemiológicos , Estudos Transversais , Pandemias , Anticorpos AntiviraisRESUMO
Gammadelta-T-cell acute lymphoblastic leukemia (ALL) is a rare variant of ALL. The comparison of some clinical and laboratory features in children and adults with gammadelta-T-ALL or alphabeta-ALL showed that in gammadelta-T-ALL the CD45RAEth/CD45RO+ phenotype was predominant, the hemoglobin concentration was lower in children and the presence of splenomegaly and the white cell counts was higher in adults.
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Imunofenotipagem/métodos , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Adolescente , Criança , Pré-Escolar , Feminino , Hemoglobinas/metabolismo , Humanos , Lactente , Antígenos Comuns de Leucócito/biossíntese , Masculino , Fenótipo , Esplenomegalia/patologiaRESUMO
Polycythaemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (MF), are the most common myeloproliferative neoplasms (MPN) in patients without the BCR-ABL1 gene rearrangement. They are caused by clonal expansion of haematopoietic stem cells and share, as a diagnostic criterion, the identification of JAK2V617F mutation. Classically, when other clinical criteria are present, a JAK2V617F negative case requires the analysis of Exon12_JAK2 for the diagnosis of PV, and of MPL515K/L mutations for the diagnosis of ET and MF. Here, we evaluated 78 samples from Brazilian patients suspected to have MPN, without stratification for PV, ET or MF. We found that 28 (35.9%) are JAK2V617F carriers; from the 50 remaining samples, one (2%) showed an Exon12_JAK2 mutation, and another (2%) was positive for MPLW515L mutation. In summary, the investigation of JAK2V617F, Exon12_JAK2 and MPLW515K/L was relevant for the diagnosis of 38.4% of patients suspected to have BCR-ABL1-negative MPN, suggesting that molecular genetic tests are useful for a quick and unequivocal diagnosis of MPN.
Assuntos
Janus Quinase 2/genética , Mutação , Transtornos Mieloproliferativos/diagnóstico , Transtornos Mieloproliferativos/genética , Receptores de Trombopoetina/genética , Sequência de Bases , Análise Mutacional de DNA , Éxons/genética , Proteínas de Fusão bcr-abl/genética , Humanos , Reação em Cadeia da Polimerase em Tempo RealRESUMO
CONTEXT AND OBJECTIVE The term mastocytosis covers a group of rare disorders characterized by neoplastic proliferation and accumulation of clonal mast cells in one or more organs. The aim of this study was to assess the principal elements for diagnosing and treating these disorders. DESIGN AND SETTING Narrative review of the literature conducted at Grupo Fleury, São Paulo, Brazil. METHODS This study reviewed the scientific papers published in the PubMed, Embase (Excerpta Medica Database), Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde) and Cochrane Library databases that were identified using the search term "mastocytosis." RESULTS The clinical presentation of mastocytosis is remarkably heterogeneous and ranges from skin lesions that may regress spontaneously to aggressive forms associated with organ failure and short survival. Currently, seven subtypes of mastocytosis are recognized through the World Health Organization classification system for hematopoietic tumors. These disorders are diagnosed based on clinical manifestations and on identification of neoplastic mast cells using morphological, immunophenotypic, genetic and molecular methods. Abnormal mast cells display atypical and frequently spindle-shaped morphology, and aberrant expression of the CD25 and CD2 antigens. Elevation of serum tryptase is a common finding in some subtypes, and more than 90% of the patients present the D816V KIT mutation in mast cells. CONCLUSION Here, we described the most common signs and symptoms among patients with mastocytosis and suggested a practical approach for the diagnosis, classification and initial clinical treatment of mastocytosis.
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Mastocitose/diagnóstico , Mastocitose/terapia , Medula Óssea/patologia , Citometria de Fluxo , Humanos , Mastocitose/classificação , Mastocitose/genética , Mutação , Proteínas Proto-Oncogênicas c-kit/genéticaAssuntos
Instituições de Assistência Ambulatorial/organização & administração , Prestação Integrada de Cuidados de Saúde/organização & administração , Técnicas e Procedimentos Diagnósticos/normas , Capacitação em Serviço , Aprendizagem , Equipe de Assistência ao Paciente/organização & administração , Equipe de Assistência ao Paciente/normas , Avaliação de Processos em Cuidados de Saúde , Melhoria de Qualidade/organização & administração , Instituições de Assistência Ambulatorial/normas , Brasil , Prestação Integrada de Cuidados de Saúde/normas , Humanos , Relações Interprofissionais , Estudos de Casos Organizacionais , Padrões de Prática Médica/estatística & dados numéricosRESUMO
CONTEXT AND OBJECTIVE The term mastocytosis covers a group of rare disorders characterized by neoplastic proliferation and accumulation of clonal mast cells in one or more organs. The aim of this study was to assess the principal elements for diagnosing and treating these disorders. DESIGN AND SETTING Narrative review of the literature conducted at Grupo Fleury, São Paulo, Brazil. METHODS This study reviewed the scientific papers published in the PubMed, Embase (Excerpta Medica Database), Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde) and Cochrane Library databases that were identified using the search term “mastocytosis.” RESULTS The clinical presentation of mastocytosis is remarkably heterogeneous and ranges from skin lesions that may regress spontaneously to aggressive forms associated with organ failure and short survival. Currently, seven subtypes of mastocytosis are recognized through the World Health Organization classification system for hematopoietic tumors. These disorders are diagnosed based on clinical manifestations and on identification of neoplastic mast cells using morphological, immunophenotypic, genetic and molecular methods. Abnormal mast cells display atypical and frequently spindle-shaped morphology, and aberrant expression of the CD25 and CD2 antigens. Elevation of serum tryptase is a common finding in some subtypes, and more than 90% of the patients present the D816V KIT mutation in mast cells. CONCLUSION Here, we described the most common signs and symptoms among patients with mastocytosis and suggested a practical approach for the diagnosis, classification and initial clinical treatment of mastocytosis. .
CONTEXTO E OBJETIVO O termo mastocitose abrange um grupo de raras doenças caracterizado por proliferação neoplásica e acúmulo de mastócitos clonais em um ou mais órgãos. O objetivo do presente estudo foi avaliar os principais elementos para o diagnóstico e tratamento dessas desordens. TIPO DE ESTUDO E LOCAL Revisão narrativa da literatura realizada no Grupo Fleury, São Paulo, Brasil. MÉTODOS O presente estudo revisou artigos científicos publicados nas bases de dados PubMed, Embase (Excerpta Medica Database), Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde) e Cochrane Library, que foram identificados com o termo de busca “mastocitose”. RESULTADOS A apresentação clínica da mastocitose é marcadamente heterogênea, variando de lesões cutâneas que podem regredir espontaneamente, até formas agressivas associadas a falência de órgãos e curta sobrevida. Atualmente, sete subtipos de mastocitose são reconhecidos pela classificação de tumores hematopoéticos da Organização Mundial de Saúde; o diagnóstico é realizado com base nas manifestações clínicas e na identificação de mastócitos neoplásicos por métodos morfológicos, imunofenotípicos, genéticos e moleculares. Mastócitos anômalos apresentam morfologia atípica, frequentemente fusiforme, e expressão aberrante dos antígenos CD25 e CD2. Aumento de triptase sérica é um achado comum em alguns subtipos; e mais que 90% dos pacientes apresentam mastócitos com a mutação KIT D816V. CONCLUSÃO No presente artigo, descrevemos os sintomas e sinais mais comuns em pacientes com mastocitose e sugerimos uma prática abordagem para o diagnóstico, classificação e tratamento clínico ...
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Humanos , Mastocitose/diagnóstico , Mastocitose/terapia , Medula Óssea/patologia , Citometria de Fluxo , Mastocitose/classificação , Mastocitose/genética , Mutação , Proteínas Proto-Oncogênicas c-kit/genéticaAssuntos
Proliferação de Células , Mieloma Múltiplo/patologia , Células-Tronco Neoplásicas/patologia , Animais , Carcinogênese/efeitos dos fármacos , Carcinogênese/imunologia , Humanos , Imunossupressores/imunologia , Imunossupressores/uso terapêutico , Camundongos , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/imunologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/imunologia , Talidomida/imunologia , Talidomida/uso terapêutico , Transplante Heterólogo , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/imunologiaRESUMO
Bortezomib is more active against mantle cell lymphoma (MCL) than against most other lymphoma subtypes. Nevertheless, up to half of patients with MCL have bortezomib resistant disease. Factors contributing to intrinsic resistance to bortezomib have not been determined. Here we used a panel of eight bortezomib sensitive (median IC(50) 5.9 nM) and three relatively bortezomib resistant cell lines (median IC(50) 12.9 nM) to investigate differences in tumor biology that could determine sensitivity to bortezomib. Bortezomib effectively inhibited high baseline proteasome activity and induced a comparable degree of proteasome inhibition in both sensitive and resistant cells. At 10 nM, bortezomib induced the proapoptotic BH3-only protein Noxa in sensitive but not resistant cells. At higher concentrations of bortezomib, however, Noxa was also upregulated in resistant cells and this effect was sufficient to induce apoptosis. Silencing of Noxa with siRNA rescued these cells from apoptosis, arguing against a defect in Noxa regulation or function as the basis of bortezomib resistance. Bortezomib was equally effective against cells with high and low constitutive NF-kappaB signaling. Also, sensitive and resistant MCL cell lines showed comparable activation of the AKT pathway. We conclude that bortezomib can overcome classic mechanisms of resistance to apoptosis and that determinants of bortezomib sensitivity in MCL are due to differences in signaling or stress pathways upstream of Noxa.
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Apoptose/efeitos dos fármacos , Ácidos Borônicos/farmacologia , Linfoma de Célula do Manto/patologia , NF-kappa B/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/fisiologia , Pirazinas/farmacologia , Bortezomib , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Humanos , Linfoma de Célula do Manto/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-2/genética , Transdução de Sinais , Regulação para CimaRESUMO
A high frequency of mtDNA somatic mutation has been observed in many tumors as well as in aging tissues. In this study, we analyzed the mtDNA control region sequence variation in 3534 single normal cells and individual blasts from 18 patients with leukemia and 10 healthy donors, to address the mutation process in leukemic cells. We found significant differences in mtDNA sequence, as represented by the number of haplotypes and the mean number of cells with each nonaggregate haplotype in a population of cells, in patients compared to controls. Patients with similar clinical leukemia types, particularly acute myeloid leukemia (AML), did not show a uniform pattern of sequence variation in single blasts. Some patients at relapse presented a complex shift of major haplotypes in single cells. Four patients showed high frequencies of cells containing mutations 189, 260, 16150, and 16488, respectively, as a result of clonal expansion and could be considered as potential markers for their respective disease progression. To our knowledge, this is the first large-scale study of mtDNA variation in single malignant cells. Our results suggest that the somatic mutation process in leukemia is complex, leading to diverse levels of genetic alterations due to either intrinsic aspects of leukemia pathophysiology or chemotherapy effects.
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Núcleo Celular/genética , DNA Mitocondrial/genética , Variação Genética , Leucemia/genética , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutação Puntual , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Sensibilidade e Especificidade , Análise de Sequência de DNA/métodos , Deleção de SequênciaRESUMO
Microarray studies have revealed the differential expression of several genes in mantle cell lymphoma (MCL), but it is unknown which of these differences are dependent on the transformed MCL cell itself or on the tumour microenvironment. To investigate which genes and signalling pathways are aberrantly expressed in MCL cells we used oligonucleotide microarrays to perform gene expression profiling of both purified leukaemic MCL cells and their normal counterparts, the naive B cells. A total of 106 genes were differentially expressed at least threefold in MCL cells compared with naive B cells; 63 upregulated and 43 downregulated. To validate the microarray results in a larger set of samples, we selected 10 differentially expressed genes and quantified their expression by real-time polymerase chain reaction in peripheral blood of MCL patients (n=21), purified MCL cells (n=6) and naive B cells (n=4), obtaining fully concordant results. A computer-assisted approach was used to procure specific molecular signalling pathways that were aberrantly expressed in MCL cells. Several genes related to apoptosis and to the PI3K/AKT, WNT and tumour growth factor beta signalling pathways were altered in MCL cells when compared with naive B cells. These pathways may play a significant role in the pathogenesis of MCL and deserve further investigation as candidates for new therapeutic targets.