RESUMO
OBJECTIVE: To investigate whether in utero opioid exposure, which has been linked to adverse neurodevelopmental and social outcomes, is associated with altered DNA methylation of opioid-related genes at birth. STUDY DESIGN: Observational cohort study of 21 healthy methadone-maintained opioid-dependent mother-infant dyads consecutively delivered at >36 weeks of gestation, and 2 comparator groups: smoking, "deprived" opioid-naïve mother-infant dyads (n = 17) and nonsmoking, "affluent" opioid-naïve mother-infant dyads (n = 15). DNA methylation of ABCB1, CYP2D6, and OPRM1 genes for mothers and babies was determined from buccal swabs. Plasma methadone concentrations were additionally measured for methadone-maintained opioid-dependent mothers. RESULTS: DNA methylation for ABCB1 and CYP2D6 was similar in opioid-naïve infants compared with their mothers, but was less for OPRM1 (3 ± 1.6% vs 8 ± 1%, P < .0005). Opioid-exposed newborns had similar DNA methylation to their mothers for all genes studied and greater methylation of ABCB1 (18 ± 4.8% vs 3 ± 0.5%), CYP2D6 (92 ± 1.2% vs 89 ± 2.4%), and OPRM1 (8 ± 0.3% vs 3 ± 1.6%) compared with opioid-naïve newborns (P < .0005 for all 3 genes). Infant DNA methylation was not related to birth weight, length of hospital stay, maternal smoking, dose or plasma concentration of methadone at delivery, or postcode of residence. CONCLUSIONS: In utero exposure to opioids is associated with increased methylation of opioid-related genes in the newborn infant. It is not clear whether these findings are due to opioid exposure per se or other associated lifestyle factors.
Assuntos
Citocromo P-450 CYP2D6/genética , Metilação de DNA , Tratamento de Substituição de Opiáceos/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal/genética , Receptores Opioides mu/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Adulto , Analgésicos Opioides/efeitos adversos , Analgésicos Opioides/uso terapêutico , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Marcadores Genéticos , Humanos , Recém-Nascido , Metadona/efeitos adversos , Metadona/uso terapêutico , Transtornos Relacionados ao Uso de Opioides/tratamento farmacológico , Gravidez , Complicações na Gravidez/tratamento farmacológico , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Fatores de Risco , Fumar/efeitos adversos , Fatores SocioeconômicosAssuntos
Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Dano ao DNA , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/metabolismo , Polimorfismo Genético , Transdução de Sinais , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Alelos , Expressão Gênica , Genótipo , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Polimorfismo de Nucleotídeo ÚnicoRESUMO
NKX2 homeobox family proteins have a role in cancer development. Here we show that NKX2-3 is overexpressed in tumour cells from a subset of patients with marginal-zone lymphomas, but not with other B-cell malignancies. While Nkx2-3-deficient mice exhibit the absence of marginal-zone B cells, transgenic mice with expression of NKX2-3 in B cells show marginal-zone expansion that leads to the development of tumours, faithfully recapitulating the principal clinical and biological features of human marginal-zone lymphomas. NKX2-3 induces B-cell receptor signalling by phosphorylating Lyn/Syk kinases, which in turn activate multiple integrins (LFA-1, VLA-4), adhesion molecules (ICAM-1, MadCAM-1) and the chemokine receptor CXCR4. These molecules enhance migration, polarization and homing of B cells to splenic and extranodal tissues, eventually driving malignant transformation through triggering NF-κB and PI3K-AKT pathways. This study implicates oncogenic NKX2-3 in lymphomagenesis, and provides a valid experimental mouse model for studying the biology and therapy of human marginal-zone B-cell lymphomas.
Assuntos
Proteínas de Homeodomínio/genética , Linfócitos/metabolismo , Linfoma de Zona Marginal Tipo Células B/genética , Receptores de Antígenos de Linfócitos B/genética , Transdução de Sinais/genética , Fatores de Transcrição/genética , Animais , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Perfilação da Expressão Gênica , Proteínas de Homeodomínio/metabolismo , Humanos , Estimativa de Kaplan-Meier , Tecido Linfoide/metabolismo , Linfoma de Zona Marginal Tipo Células B/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosforilação , Receptores de Antígenos de Linfócitos B/metabolismo , Quinase Syk/genética , Quinase Syk/metabolismo , Fatores de Transcrição/metabolismoRESUMO
IGHV gene mutational status has prognostic significance in chronic lymphocytic leukaemia (CLL) but the percentage of mutations that correlates best with clinical outcome remains controversial. We initially studied 558 patients from diagnosis and found significant differences in median time to first treatment (TTFT) among Stage A patients and in overall survival (OS) for the whole cohort, between cases with <97% and 97-98·99% identity and between cases with 97-98·99% and ≥99% identity, when cases from the IGHV3-21 Stereotype Subset #2 were excluded. A significant difference in progression-free survival (PFS) and OS between those with <97% and 97-98·99% identity, but not between those with 97-98·99% and ≥99% identity was also observed in a validation cohort comprising 460 patients in the UK CLL4 trial. Cox Regression analyses in the Stage A cohort revealed that a model which incorporated <97%, 97-98·99% and ≥99% identity as subgroups, was a better predictor of TTFT in CLL than using the 98% cut-off. Multivariate analysis selected the three mutational subgroups as independent predictors of TTFT in Stage A patients, and of OS in the diagnostic cohort. This study highlights that cases with 97% identity should not be considered to have the same prognosis as other cases with mutated IGHV genes defined as <98% identity to germline.
Assuntos
Cadeias Pesadas de Imunoglobulinas/genética , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/mortalidade , Modelos Biológicos , Mutação , Adolescente , Adulto , Criança , Pré-Escolar , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Lactente , Recém-Nascido , Masculino , Taxa de SobrevidaRESUMO
PURPOSE: Mounting evidence supports the clinical significance of gene mutations and immunogenetic features in common mature B-cell malignancies. EXPERIMENTAL DESIGN: We undertook a detailed characterization of the genetic background of splenic marginal zone lymphoma (SMZL), using targeted resequencing and explored potential clinical implications in a multinational cohort of 175 patients with SMZL. RESULTS: We identified recurrent mutations in TP53 (16%), KLF2 (12%), NOTCH2 (10%), TNFAIP3 (7%), MLL2 (11%), MYD88 (7%), and ARID1A (6%), all genes known to be targeted by somatic mutation in SMZL. KLF2 mutations were early, clonal events, enriched in patients with del(7q) and IGHV1-2*04 B-cell receptor immunoglobulins, and were associated with a short median time to first treatment (0.12 vs. 1.11 years; P = 0.01). In multivariate analysis, mutations in NOTCH2 [HR, 2.12; 95% confidence interval (CI), 1.02-4.4; P = 0.044] and 100% germline IGHV gene identity (HR, 2.19; 95% CI, 1.05-4.55; P = 0.036) were independent markers of short time to first treatment, whereas TP53 mutations were an independent marker of short overall survival (HR, 2.36; 95 % CI, 1.08-5.2; P = 0.03). CONCLUSIONS: We identify key associations between gene mutations and clinical outcome, demonstrating for the first time that NOTCH2 and TP53 gene mutations are independent markers of reduced treatment-free and overall survival, respectively.
Assuntos
Linfoma de Zona Marginal Tipo Células B/diagnóstico , Linfoma de Zona Marginal Tipo Células B/genética , Mutação , Neoplasias Esplênicas/diagnóstico , Neoplasias Esplênicas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Análise Mutacional de DNA , Proteínas de Ligação a DNA/genética , Feminino , Marcadores Genéticos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Fatores de Transcrição Kruppel-Like/genética , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Fator 88 de Diferenciação Mieloide/genética , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Prognóstico , Receptor Notch2/genética , Fatores de Risco , Fatores de Transcrição/genética , Resultado do Tratamento , Proteína 3 Induzida por Fator de Necrose Tumoral alfa , Proteína Supressora de Tumor p53/genéticaAssuntos
Linfócitos B , Leucemia Linfocítica Crônica de Células B/diagnóstico , Leucemia Linfocítica Crônica de Células B/genética , Linfocitose/diagnóstico , Linfocitose/genética , Mutação/genética , Idoso , Linfócitos B/patologia , Estudos de Coortes , Feminino , Humanos , Leucemia Linfocítica Crônica de Células B/mortalidade , Linfocitose/mortalidade , Masculino , Valor Preditivo dos Testes , Taxa de Sobrevida/tendências , Resultado do TratamentoRESUMO
A number of single nucleotide polymorphisms have been associated with disease predisposition in chronic lymphocytic leukemia. A single nucleotide polymorphism in the MDM2 promotor region, MDM2SNP309, was shown to soothe the p53 pathway. In the current study, we aimed to clarify the effect of the MDM2SNP309 on chronic lymphocytic leukemia characteristics and outcome. We performed a meta-analysis of data from 2598 individual patients from 10 different cohorts. Patients' data and genetic analysis for MDM2SNP309 genotype, immunoglobulin heavy chain variable region mutation status and fluorescence in situ hybridization results were collected. There were no differences in overall survival based on the polymorphism (log rank test, stratified by study cohort; P=0.76; GG genotype: cohort-adjusted median overall survival of 151 months; TG: 153 months; TT: 149 months). In a multivariable Cox proportional hazards regression analysis, advanced age, male sex and unmutated immunoglobulin heavy chain variable region genes were associated with inferior survival, but not the MDM2 genotype. The MDM2SNP309 is unlikely to influence disease characteristics and prognosis in chronic lymphocytic leukemia. Studies investigating the impact of individual single nucleotide polymorphisms on prognosis are often controversial. This may be due to selection bias and small sample size. A meta-analysis based on individual patient data provides a reasonable strategy for prognostic factor analyses in the case of small individual studies. Individual patient data-based meta-analysis can, therefore, be a powerful tool to assess genetic risk factors in the absence of large studies.
Assuntos
Bases de Dados Factuais , Leucemia Linfocítica Crônica de Células B/diagnóstico , Leucemia Linfocítica Crônica de Células B/genética , Polimorfismo de Nucleotídeo Único/genética , Regiões Promotoras Genéticas/genética , Proteínas Proto-Oncogênicas c-mdm2/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Bases de Dados Factuais/tendências , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
ATM mutation and BIRC3 deletion and/or mutation have independently been shown to have prognostic significance in chronic lymphocytic leukemia. However, the relative clinical importance of these abnormalities in patients with a deletion of 11q encompassing the ATM gene has not been established. We screened a cohort of 166 patients enriched for 11q-deletions for ATM mutations and BIRC3 deletion and mutation and determined the overall and progression-free survival among the 133 of these cases treated within the UK LRF CLL4 trial. SNP6.0 profiling demonstrated that BIRC3 deletion occurred in 83% of 11q-deleted cases and always co-existed with ATM deletion. For the first time we have demonstrated that 40% of BIRC3-deleted cases have concomitant deletion and mutation of ATM. While BIRC3 mutations were rare, they exclusively occurred with BIRC3 deletion and a wild-type residual ATM allele. In 11q-deleted cases, we confirmed that ATM mutation was associated with a reduced overall and progression-free survival comparable to that seen with TP53 abnormalities, whereas BIRC3 deletion and/or mutation had no impact on overall and progression-free survival. In conclusion, in 11q-deleted patients treated with first-line chemotherapy, ATM mutation rather than BIRC3 deletion and/or mutation identifies a subgroup with a poorer outcome.
Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Cromossomos Humanos Par 11 , Proteínas Inibidoras de Apoptose/genética , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/mortalidade , Mutação , Deleção de Sequência , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteína 3 com Repetições IAP de Baculovírus , Aberrações Cromossômicas , Feminino , Deleção de Genes , Humanos , Leucemia Linfocítica Crônica de Células B/diagnóstico , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Avaliação de Resultados da Assistência ao Paciente , Polimorfismo de Nucleotídeo Único , Prognóstico , Ubiquitina-Proteína LigasesRESUMO
Telomerase activity and telomere length (TL) are prognostic markers in chronic lymphocytic leukemia (CLL). The rate-limiting component of telomerase is human telomerase reverse transcriptase (hTERT), for which multiple transcripts exist. Two splicing sites, α and ß, have been described that generate deleted transcripts. Only the full-length (FL; αâºßâº) transcript translates into a functional protein. The aim of this work was to characterize hTERT splice variants in CLL in relation to disease activity, clinical stage, immunoglobulin heavy chain variable (IGHV) genes mutational status, and TL. Real-time polymerase chain reaction assays were validated for quantification of the hTERT transcripts with either α deletion (del-α; αâ»ßâº)), ß deletion (del-ß; αâºßâ») or both α and ß deletions (del-αß; αâ»ßâ»). The splice variant expression pattern was studied in 97 patients with CLL, 6 healthy control subjects, and one CD34 cell sample. TL was assessed with real-time polymerase chain reaction in 71 of 97 samples. Thirty-two percent of the cases did not express any of the splice variants. Average FL expression was 5.5-fold higher in IGHV-unmutated (n = 35) compared with mutated (n = 59) patients (p < 0.0001). FL levels correlated directly with the percentage of IGHV homology (r = 0.34; p = 0.0007) and inversely with TL (r = -0.44; p = 0.0001). Overall, FL expression correlated significantly with that of the other splice variants. All transcripts were more frequently expressed in progressive compared with nonprogressive patients (p < 0.0001 for FL and del-α; p = 0.01 for del-ß; and p = 0.006 for del-αß). This study provides a detailed insight into the hTERT transcript pattern in CLL, highlighting the necessity of subgrouping patients according to IGHV mutation status when analyzing hTERT expression.
Assuntos
Leucemia Linfocítica Crônica de Células B/genética , Proteínas de Neoplasias/genética , Telomerase/genética , Telômero/ultraestrutura , Idoso , Processamento Alternativo , Progressão da Doença , Feminino , Regulação Leucêmica da Expressão Gênica , Genes de Imunoglobulinas , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Isoenzimas/genética , Isoenzimas/fisiologia , Leucemia Linfocítica Crônica de Células B/enzimologia , Masculino , Proteínas de Neoplasias/fisiologia , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , RNA Neoplásico/biossíntese , RNA Neoplásico/genética , Reação em Cadeia da Polimerase em Tempo Real , Telomerase/fisiologiaRESUMO
CLLU1, located at chromosome 12q22, encodes a transcript specific to chronic lymphocytic leukemia and has potential prognostic value. We assessed the value of CLLU1 expression in the LRF CLL4 randomized trial. Samples from 515 patients with chronic lymphocytic leukemia were collected immediately before the start of treatment. After RNA extraction and cDNA synthesis, CLLU1 expression was assessed by quantitative polymerase chain reaction. In total, 247 and 268 samples were identified as having low and high CLLU1 expression, respectively. The median follow-up was 88 months. High CLLU1 expression was significantly correlated with unmutated IGHV genes, ZAP-70 and CD38 positivity, and absence of 13q deletion (all r>0.2, P<0.0001). At 6 years, patients with high CLLU1 expression had significantly worse progression-free survival (9% versus 17%; P=0.03) and overall survival (42% versus 57%; P=0.0003) than patients with low CLLU1 expression. Among patients with mutated IGHV genes, overall survival at 6 years was 50% in those with high CLLU1 expression and 76% in those with low CLLU1 expression (P=0.005). However, CLLU1 expression was not an independent predictor of overall survival in a multivariate model including TP53 aberrations, beta-2 microglobulin level, age and IGHV mutation status. Nor did it predict response to treatment. CLLU1 expression analysis helps to refine the prognosis of patients with chronic lymphocytic leukemia who have mutated IGHV genes.
Assuntos
Expressão Gênica , Cadeias Pesadas de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/genética , Mutação , Proteínas de Neoplasias/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , RNA Longo não Codificante , Resultado do TratamentoRESUMO
NOTCH1 and SF3B1 mutations have been previously reported to have prognostic significance in chronic lymphocytic leukemia but to date they have not been validated in a prospective, controlled clinical trial. We have assessed the impact of these mutations in a cohort of 494 patients treated within the randomized phase 3 United Kingdom Leukaemia Research Fund Chronic Lymphocytic Leukemia 4 (UK LRF CCL4) trial that compared chlorambucil and fludarabine with and without cyclophosphamide in previously untreated patients. We investigated the relationship of mutations in NOTCH1 (exon 34) and SF3B1 (exon 14-16) to treatment response, survival and a panel of established biologic variables. NOTCH1 and SF3B1 mutations were found in 10% and17% of patients, respectively. NOTCH1 mutations correlated with unmutated IGHV genes, trisomy 12, high CD38/ ZAP-70 expression and were associated with reduced overall (median 54.8 vs 74.6 months, P = .02) and progression-free (median 22.0 vs 26.4 months, P = .02) survival. SF3B1 mutations were significantly associated with high CD38 expression and with shorter overall survival (median 54.3 vs 79.0 months, P < .001). Furthermore, multivariate analysis, including baseline clinical variables, treatment, and adverse prognostic factors demonstrated that although TP53 alterations remained the most informative marker of dismal survival in this cohort, NOTCH1 (HR 1.58, P = .03) and SF3B1 (HR 1.52, P = .01) mutations have added independent prognostic value.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/genética , Fosfoproteínas/genética , Receptor Notch1/genética , Ribonucleoproteína Nuclear Pequena U2/genética , ADP-Ribosil Ciclase 1/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos Alquilantes/uso terapêutico , Biomarcadores Tumorais/genética , Clorambucila/uso terapêutico , Cromossomos Humanos Par 12/genética , Ciclofosfamida/uso terapêutico , Educação Médica Continuada , Feminino , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Incidência , Leucemia Linfocítica Crônica de Células B/mortalidade , Masculino , Glicoproteínas de Membrana/genética , Pessoa de Meia-Idade , Prognóstico , Fatores de Processamento de RNA , Fatores de Risco , Trissomia/genética , Proteína Supressora de Tumor p53/genética , Vidarabina/análogos & derivados , Vidarabina/uso terapêuticoRESUMO
PURPOSE: The prognostic significance of ATM mutations in chronic lymphocytic leukemia (CLL) is unclear. We assessed their impact in the context of a prospective randomized trial. PATIENTS AND METHODS: We analyzed the ATM gene in 224 patients treated on the Leukemia Research Fund Chronic Lymphocytic Leukemia 4 (LRF-CLL4) trial with chlorambucil or fludarabine with and without cyclophosphamide. ATM status was analyzed by denaturing high-performance liquid chromatography and was related to treatment response, survival, and the impact of TP53 alterations for the same patient cohort. RESULTS: We identified 36 ATM mutations in 33 tumors, 16 with and 17 without 11q deletion. Mutations were associated with advanced disease stage and involvement of multiple lymphoid sites. Patients with both ATM mutation and 11q deletion showed significantly reduced progression-free survival (median, 7.4 months) compared with those with ATM wild type (28.6 months), 11q deletion alone (17.1 months), or ATM mutation alone (30.8 months), but survival was similar to that in patients with monoallelic (6.7 months) or biallelic (3.4 months) TP53 alterations. This effect was independent of treatment, immunoglobulin heavy chain variable gene (IGHV) status, age, sex, or disease stage. Overall survival for patients with biallelic ATM alterations was also significantly reduced compared with those with ATM wild type or ATM mutation alone (median, 42.2 v 85.5 v 77.6 months, respectively). CONCLUSION: The combination of 11q deletion and ATM mutation in CLL is associated with significantly shorter progression-free and overall survival following first-line treatment with alkylating agents and purine analogs. Assessment of ATM mutation status in patients with 11q deletion may influence the choice of subsequent therapy.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteínas de Ciclo Celular/genética , Clorambucila/uso terapêutico , Proteínas de Ligação a DNA/genética , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/genética , Mutação , Proteínas Serina-Treonina Quinases/genética , Proteínas Supressoras de Tumor/genética , Vidarabina/análogos & derivados , Idoso , Alelos , Proteínas Mutadas de Ataxia Telangiectasia , Ciclofosfamida/administração & dosagem , Progressão da Doença , Intervalo Livre de Doença , Feminino , Regulação Enzimológica da Expressão Gênica , Regulação Leucêmica da Expressão Gênica , Inativação Gênica , Humanos , Leucemia Linfocítica Crônica de Células B/enzimologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Análise de Sobrevida , Reino Unido , Vidarabina/administração & dosagem , Vidarabina/uso terapêuticoRESUMO
Using high-resolution genomic microarray analysis, a distinct genomic profile was defined in 114 samples from patients with splenic marginal zone lymphoma (SMZL). Deletion or uniparental disomy of chromosome 7q were detected in 42 of 114 (37%) SMZLs but in only nine of 170 (5%) mature B-cell lymphomas (P < 0·00001). The presence of unmutated IGHV, genomic complexity, 17p13-TP53 deletion and 8q-MYC gain, but not 7q deletion, correlated with shorter overall survival of SMZL patients. Mapping studies narrowed down a commonly deleted region of 2·7 Mb in 7q32.1-q32.2 spanning a region between the SND1 and COPG2 genes. High-throughput sequencing analysis of the 7q32-deleted segment did not identify biallelic deletions/insertions or clear pathogenic gene mutations, but detected six nucleotide changes in IRF5 (n = 2), TMEM209 (n = 2), CALU (n = 1) and ZC3HC1 (n = 1) not found in healthy individuals. Comparative expression analysis found a fourfold down-regulation of IRF5 gene in lymphomas with 7q32 deletion versus non-deleted tumours (P = 0·032). Ectopic expression of IRF5 in marginal-zone lymphoma cells decreased proliferation and increased apoptosis in vitro, and impaired lymphoma development in vivo. These results show that cryptic deletions, insertions and/or point mutations inactivating genes within 7q32 are not common in SMZL, and suggest that IRF5 may be a haploinsufficient tumour suppressor in this lymphoma entity.
Assuntos
Cromossomos Humanos Par 7/genética , Genes Supressores de Tumor , Estudos de Associação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Fatores Reguladores de Interferon/genética , Linfoma de Zona Marginal Tipo Células B/genética , Proteínas de Neoplasias/genética , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Deleção de Sequência , Neoplasias Esplênicas/genética , Animais , Apoptose/genética , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral/transplante , Cromossomos Humanos Par 7/ultraestrutura , Hibridização Genômica Comparativa , Regulação Neoplásica da Expressão Gênica , Genes de Imunoglobulinas , Humanos , Fatores Reguladores de Interferon/biossíntese , Fatores Reguladores de Interferon/deficiência , Fatores Reguladores de Interferon/fisiologia , Estimativa de Kaplan-Meier , Linfoma de Zona Marginal Tipo Células B/mortalidade , Linfoma de Zona Marginal Tipo Células B/patologia , Camundongos , Camundongos Knockout , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/fisiologia , Mutação Puntual , Reação em Cadeia da Polimerase em Tempo Real , Neoplasias Esplênicas/mortalidade , Neoplasias Esplênicas/patologia , Translocação GenéticaRESUMO
Zeta-associated protein of 70 kD (ZAP70) is a recognized adverse prognostic marker in chronic lymphocytic leukaemia (CLL) associated with enhanced B-cell receptor signalling, significantly more aggressive disease course and poor overall survival. Zeta-associated protein of 70 kD is ordinarily expressed in T cells where it has a crucial role in T-cell receptor signalling, whereas its aberrant expression in CLL leads to enhanced B-cell receptor signalling and significantly more aggressive disease course. Although much is known about the activation of ZAP70 following engagement of T-cell receptor, there are little data on the regulation of ZAP70 gene expression in normal T cells or CLL. To understand the molecular events underpinning epigenetic regulation of ZAP70 gene in CLL, we have defined ZAP70 promoter region and outlined the regions crucial in regulating the gene activity. Following a direct comparison of ZAP70+ and ZAP70- primary CLLs, we show ZAP70 promoter in expressing CLLs to be associated with a spectrum of active histone modifications, some of which are tightly linked to aberrant DNA methylation in CLL. Cross-talk between histone modifications and reduced DNA methylation culminates in transcriptional de-repression of ZAP70. Moreover, treatment with histone deacetylase (HDAC) and DNA methylation inhibitors results in recovery of ZAP70 expression, which provides a possible explanation for the failure of HDAC inhibitors in CLL treatment and might serve as a cautionary warning for their future use in treatment of this leukaemia.
Assuntos
Metilação de DNA , Regulação Leucêmica da Expressão Gênica , Histonas/metabolismo , Leucemia Linfocítica Crônica de Células B/genética , Proteína-Tirosina Quinase ZAP-70/metabolismo , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Linfócitos B/metabolismo , Western Blotting , Linhagem Celular , Cromatina/química , Imunoprecipitação da Cromatina , Decitabina , Epigênese Genética , Inativação Gênica , Inibidores de Histona Desacetilases/farmacologia , Histonas/genética , Humanos , Leucemia Linfocítica Crônica de Células B/patologia , Leucócitos Mononucleares/citologia , Regiões Promotoras Genéticas , Transdução de Sinais , Sítio de Iniciação de Transcrição , Proteína-Tirosina Quinase ZAP-70/genéticaRESUMO
Chronic lymphocytic leukemia (CLL) exhibits a very variable clinical course. Altered DNA methylation of genes has shown promise as a source of novel prognostic makers in a number of cancers. Here we have studied the potential utility of a panel of methylation markers (CD38, HOXA4 and BTG4) in 118 CLL patients. Each of the three loci assessed exhibited frequent methylation, as determined by COBRA analysis, and individually correlated with either good (CD38, BTG4 methylation) or poor (HOXA4 methylation) prognosis. Using a combined approach to produce an overall methylation score, we found that methylation score was significantly associated with time to first treatment in CLL patients. Multivariate Cox regression analysis revealed that methylation score was the strongest predictor of time to first treatment, and was independent of IGHV gene mutational status and CD38 expression. This study provides proof of principle that a panel of methylation markers can be used for additional risk stratification of CLL patients.
Assuntos
Biomarcadores Tumorais/genética , Metilação de DNA , Leucemia Linfocítica Crônica de Células B/diagnóstico , ADP-Ribosil Ciclase 1/genética , ADP-Ribosil Ciclase 1/metabolismo , Biomarcadores Tumorais/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Estudos de Coortes , Feminino , Genes de Cadeia Pesada de Imunoglobulina , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Leucemia Linfocítica Crônica de Células B/epidemiologia , Leucemia Linfocítica Crônica de Células B/genética , Masculino , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Mutação , Modelos de Riscos Proporcionais , Fatores de Risco , Fatores de TranscriçãoRESUMO
To identify new risk variants for chronic lymphocytic leukemia (CLL), we conducted a genome-wide association study of 299,983 tagging SNPs, with validation in four additional series totaling 2,503 cases and 5,789 controls. We identified four new risk loci for CLL at 2q37.3 (rs757978, FARP2; odds ratio (OR) = 1.39; P = 2.11 x 10(-9)), 8q24.21 (rs2456449; OR = 1.26; P = 7.84 x 10(-10)), 15q21.3 (rs7169431; OR = 1.36; P = 4.74 x 10(-7)) and 16q24.1 (rs305061; OR = 1.22; P = 3.60 x 10(-7)). We also found evidence for risk loci at 15q25.2 (rs783540, CPEB1; OR = 1.18; P = 3.67 x 10(-6)) and 18q21.1 (rs1036935; OR = 1.22; P = 2.28 x 10(-6)). These data provide further evidence for genetic susceptibility to this B-cell hematological malignancy.
Assuntos
Cromossomos Humanos/genética , Predisposição Genética para Doença , Variação Genética , Leucemia Linfocítica Crônica de Células B/genética , Alelos , Loci Gênicos/genética , Genoma Humano/genética , Humanos , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
The protein tyrosine kinase zeta-chain associated protein kinase (ZAP70), normally expressed in T cells and a subset of B cells, is solely expressed in poor prognosis chronic lymphocytic leukaemia and implicated in enhanced B cell receptor signalling. As a result, the expression of this protein provides an ideal prognostic marker for the disease. A previous study has shown differential CpG methylation of a 5' region of ZAP70 in leukaemic lymphoid cells, although no further epigenetic studies have been reported. Further investigation into the expression of ZAP70 may therefore provide targets for therapies.
Assuntos
Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/metabolismo , Proteína-Tirosina Quinase ZAP-70/genética , Proteína-Tirosina Quinase ZAP-70/metabolismo , Animais , Ativação Enzimática , Regulação Neoplásica da Expressão Gênica , Humanos , Leucemia Linfocítica Crônica de Células B/enzimologia , Leucemia Linfocítica Crônica de Células B/patologia , Linfócitos/metabolismo , Linfócitos/patologia , Proteína-Tirosina Quinase ZAP-70/químicaRESUMO
PURPOSE: The HOX genes comprise a large family of homeodomain-containing transcription factors, present in four separate clusters, which are key regulators of embryonic development, hematopoietic differentiation, and leukemogenesis. We aimed to study the role of DNA methylation as an inducer of HOX gene silencing in leukemia. EXPERIMENTAL DESIGN: Three hundred and seventy-eight samples of myeloid and lymphoid leukemia were quantitatively analyzed (by COBRA analysis and pyrosequencing of bisulfite-modified DNA) for methylation of eight HOXA and HOXB cluster genes. The biological significance of the methylation identified was studied by expression analysis and through re-expression of HOXA5 in a chronic myeloid leukemia (CML) blast crisis cell line model. RESULTS: Here, we identify frequent hypermethylation and gene inactivation of HOXA and HOXB cluster genes in leukemia. In particular, hypermethylation of HOXA4 and HOXA5 was frequently observed (26-79%) in all types of leukemias studied. HOXA6 hypermethylation was predominantly restricted to lymphoid malignancies, whereas hypermethylation of other HOXA and HOXB genes was only observed in childhood leukemia. HOX gene methylation exhibited clear correlations with important clinical variables, most notably in CML, in which hypermethylation of both HOXA5 (P = 0.00002) and HOXA4 (P = 0.006) was strongly correlated with progression to blast crisis. Furthermore, re-expression of HOXA5 in CML blast crisis cells resulted in the induction of markers of granulocytic differentiation. CONCLUSION: We propose that in addition to the oncogenic role of some HOX family members, other HOX genes are frequent targets for gene inactivation and normally play suppressor roles in leukemia development.
Assuntos
Metilação de DNA , Proteínas de Homeodomínio/genética , Leucemia/genética , Crise Blástica , Ilhas de CpG , Humanos , Leucemia/mortalidade , Leucemia/patologia , Leucemia Linfoide/genética , Leucemia Linfoide/mortalidade , Leucemia Linfoide/patologia , Leucemia Mieloide/genética , Leucemia Mieloide/mortalidade , Leucemia Mieloide/patologia , Prognóstico , Fatores de TranscriçãoRESUMO
ZAP-70 has emerged as a protein of potential prognostic importance in chronic lymphocytic leukemia (CLL) following gene expression profiling which compared the 2 well established prognostic sub-sets, those with unmutated and mutated IgVH genes. This protein tyrosine kinase (PTK), known to be of importance in T and NK cell signaling but absent in normal peripheral B cells, is expressed in the majority of the poorer prognosis unmutated CLL and absent in most cases with mutated IgVH genes. ZAP-70 has been shown to be functionally important in the CLL cases in which it is expressed; it is also important in B cell development in mice and there is preliminary evidence for its expression in human B cell progenitors and activated B cells. Whether its expression in a sub-set of CLL cases is a result of a more activated cell type or a reflection of the stage of maturation of the transforming event(s) in CLL is open to debate. ZAP-70 is expressed in a minority of other B cell tumors but correlation with IgVH gene mutational status is lacking. The problems with ZAP-70 measurement, which has yet to be standardized, are reviewed together with its current status as a prognostic marker in CLL.
Assuntos
Leucemia de Células B/enzimologia , Leucemia Linfocítica Crônica de Células B/enzimologia , Proteína-Tirosina Quinase ZAP-70/metabolismo , Linfócitos B/enzimologia , Biomarcadores Tumorais/análise , Humanos , Células Matadoras Naturais/enzimologia , Linfoma de Células B/enzimologia , Prognóstico , Transdução de Sinais , Linfócitos T/enzimologiaRESUMO
BACKGROUND AND OBJECTIVES: ZAP-70 expression is a recognized prognostic marker in chronic lymphocytic leukemia (CLL). The aim of this study was to analyze whether the methylation status of the ZAP-70 gene is associated with expression of the ZAP-70 protein. DESIGN AND METHODS: Patients with CLL (n=87), acute lymphoblastic leukemia (n=13), mantle cell leukemia (n=13) and splenic marginal zone lymphoma (n=14) of known immunoglobulin gene mutation (IgVH) status were studied. The methylation status of the 5' region of ZAP-70 was analyzed by combined bisulphite restriction analysis (COBRA), southern blotting and bisulphite sequencing in 10 CLL patients and in normal T/NK and B cells. Further COBRA of a single CpG site located 334bp downstream of the ZAP-70 transcription start site (C-334) was then performed on all patients. RESULTS: ZAP-70 expression status in CLL and normal peripheral blood lymphocytes is associated with the methylation status of the intron1-exon2 boundary region of ZAP-70 and methylation status of C-334 determined by COBRA is representative of methylation in this region. Of 87 CLL patients, 51/53 ZAP-70 negative patients had methylation at C-334 and 30/32 ZAP-70 positive patients did not have methylation (p<0.0001); a similar association was seen in all other diseases. Median survivals of methylated and unmethylated CLL patients were 211 and 85 months, respectively (p<0.0001). INTERPRETATION AND CONCLUSIONS: Measuring ZAP-70 methylation status at C-334 is a simple and reproducible method for predicting prognosis in CLL, which is closely associated with ZAP-70 expression and IgVH gene mutational status. Methylation of a highly conserved intronic region of ZAP-70 may be responsible for regulation of expression in normal and neoplastic cells.