RESUMO
Asparaginase is a standard and critical component in the therapy of childhood acute lymphoblastic leukemia. Asparagine synthetase (ASNS) and the basic region leucine zipper activating transcription factor 5 (ATF5) and arginosuccinate synthase 1 (ASS1) have been shown to mediate the antileukemic effect of asparaginase and to display variable expression between leukemia cells that are resistant and sensitive to treatment. Fourteen polymorphisms in the regulatory and coding regions of these genes were investigated for an association with acute lymphoblastic leukemia outcome. Lower event-free survival (EFS) was associated with ATF5 T1562C, tandem-repeat ASNS polymorphism, derived haplotype, and ASS1 G1343T and G34T substitutions (P ≤ .03). Associations were limited to patients who received Escherichia coli asparaginase. Variations that sustained correction for multiple testing (ATF5 T1562C, P = .005; ASNS tandem-repeat and related haplotype, P ≤ .01) were subsequently analyzed in the replication cohort. The E coli-dependent association of the ATF5 T1562 allele with reduced EFS was confirmed (P = .01). A gene-reporter assay showed that the haplotype tagged by T1562 had higher promoter activity (P ≤ .01). The remaining regulatory polymorphisms also appeared to affect ATF5 function; 2 additional high-activity haplotypes were identified (P ≤ .02) and were further corroborated by quantitative mRNA analysis in lymphoblastoid cell lines. The ATF5-regulated increase in ASNS expression in response to more efficacious E coli-induced asparagine depletion may explain our observed results.
Assuntos
Fatores Ativadores da Transcrição/genética , Fatores Ativadores da Transcrição/fisiologia , Polimorfismo Genético , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Aspartato-Amônia Ligase/genética , Aspartato-Amônia Ligase/metabolismo , Sequência de Bases , Biomarcadores Tumorais/genética , Criança , Pré-Escolar , Feminino , Regulação Enzimológica da Expressão Gênica/genética , Regulação Leucêmica da Expressão Gênica , Genótipo , Humanos , Lactente , Recém-Nascido , Desequilíbrio de Ligação , Masculino , Polimorfismo Genético/fisiologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Prognóstico , Resultado do TratamentoRESUMO
OBJECTIVE: Neuropsychological problems occurrence varies among childhood cancer survivors, and associated risk factors have not been fully deciphered. We wanted to study the role of genetic variants in behavioral problems in this population. STUDY DESIGN: Behavioral problems in pediatric acute lymphoblastic leukemia patients (n=138) were investigated longitudinally, using the Child Behavior Checklist questionnaire and multilevel statistical modeling. Thirty-four candidate polymorphisms, related to anticancer drug effects, were investigated. RESULTS: NOS3 gene functional polymorphisms showed significant association: patients homozygous for the minor allele at investigated loci showed decreased externalizing behavioral problems scores over time (t tests: T-786C n=69, P=0.003; G894T n=71, P=0.065). The effect was even more pronounced for individuals that are homozygous for the -786C844T haplotype (t test, n=69, P<0.001) and results were supported by multilevel modeling analyses (P<0.001). No such association was observed for internalizing behavioral problems. CONCLUSION: NOS3 variants modulate externalizing problems individual trajectories, likely in relationship with glucocorticoid exposure.
Assuntos
Transtornos do Comportamento Infantil/etiologia , DNA de Neoplasias/genética , Óxido Nítrico Sintase Tipo III/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/psicologia , Adolescente , Criança , Transtornos do Comportamento Infantil/induzido quimicamente , Transtornos do Comportamento Infantil/enzimologia , Transtornos do Comportamento Infantil/genética , Pré-Escolar , Seguimentos , Glucocorticoides/administração & dosagem , Glucocorticoides/efeitos adversos , Haplótipos , Homozigoto , Humanos , Lactente , Recém-Nascido , Estudos Longitudinais , Polimorfismo de Nucleotídeo Único , Leucemia-Linfoma Linfoblástico de Células Precursoras/enzimologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Inquéritos e Questionários , Sobreviventes/psicologiaRESUMO
Methotrexate and 6-mercaptopurine, important components of acute lymphoblastic leukemia treatment, are substrates for multidrug resistance-associated protein MRP4. Eight single nucleotide polymorphisms were analyzed in MRP4 gene, and 4 variants were identified as tagSNPs with frequency more than or equal to 5%. They were investigated for association with treatment responses in 275 children with acute lymphoblastic leukemia. The TC genotype of the regulatory T-1393C polymorphism was associated with better event-free survival (P = .02) and lower methotrexate plasma levels (P = .01). The CA genotype of A934C (Lys304Asn) substitution correlated in contrast with lower event-free survival (P = .02) and higher frequency of high-grade thrombocytopenia (P = .01). Gene reporter assay showed that the promoter haplotype uniquely tagged by the C-1393 allele conferred higher promoter activity compared with remaining haplotypes (P < .001). Further analyses are needed to replicate this pilot study and get closer insight into the functional effect of these polymorphisms.
Assuntos
Substituição de Aminoácidos , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Mutação de Sentido Incorreto , Polimorfismo de Nucleotídeo Único , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Adolescente , Alelos , Antimetabólitos Antineoplásicos/uso terapêutico , Criança , Pré-Escolar , Intervalo Livre de Doença , Feminino , Frequência do Gene , Genótipo , Humanos , Masculino , Mercaptopurina/uso terapêutico , Metotrexato/uso terapêutico , Projetos Piloto , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Regiões Promotoras Genéticas/genética , Estudos Retrospectivos , Taxa de SobrevidaRESUMO
Short-acting b2-adrenergic receptor agonists are commonly used bronchodilators for symptom relief in asthmatics. The aim of this study was to test whether genetic variants in PDE4D gene, a key regulator of b2-adrenoceptor-induced cAMP turnover in airway smooth muscle cells, affect the response to short-acting b2-agonists. Bronchodilator responsiveness was assessed in 133 asthmatic children by % change in baseline forced expiratory volume in one second (FEV(1)) after administration of albuterol. The analyses were performed in patients with airway obstruction (FEV(1)/FVC ratio below 90%, n = 93). FEV(1) % change adjusted for baseline FEV(1) values was significantly different between genotypes of rs1544791 G/A polymorphism (P = 0.006) and -1345 C/T (rs1504982) promoter variation (P = 0.03). The association remained significant with inclusion of age, sex, atopy, and controller medication into multivariate model (P = 0.004 and P = 0.02, resp.). Our work identifies new genetic variants implicated in modulation of asthma treatment, one of them (rs1544791) previously associated with asthma phenotype.
Assuntos
Agonistas Adrenérgicos beta/uso terapêutico , Asma/tratamento farmacológico , Asma/enzimologia , Broncodilatadores/uso terapêutico , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/genética , Polimorfismo Genético , Agonistas Adrenérgicos beta/farmacologia , Broncodilatadores/farmacologia , Criança , Pré-Escolar , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/metabolismo , Volume Expiratório Forçado/efeitos dos fármacos , Humanos , Testes de Função Respiratória , Capacidade Vital/efeitos dos fármacosRESUMO
PURPOSE: Asparaginase (ASNase) is a standard and critical component in the therapy of childhood acute lymphoblastic leukemia (ALL), but it is also associated with several toxicities. EXPERIMENTAL DESIGN: We recently reported the results of an association study between ASNase pathway genes and event-free survival (EFS) in childhood patients with ALL. The same polymorphisms were interrogated here in relation to allergies, pancreatitis, and thrombotic events following treatment with E. coli ASNase. RESULTS: Among patients of the discovery group, allergies, and pancreatitis were more frequent in individuals who are homozygous for the triple-repeat allele (3R) of the asparagine synthetase (ASNS) gene, resulting in remarkably higher risk of these toxicities associated with 3R3R genotype [OR for allergies, 14.6; 95% confidence interval (CI), 3.6-58.7; P < 0.0005 and OR for pancreatitis, 8.6; 95% CI, 2.0-37.3; P = 0.01]. In contrast, the ASNS haplotype *1 harboring double-repeat (2R) allele had protective effect against these adverse reactions (P ≤ 0.01). The same haplotype was previously reported to confer reduction in EFS. The risk effect of 3R3R genotype was not replicated in the validation cohort, whereas the protective effect of haplotype *1 against allergies was maintained (P ≤ 0.002). Analysis with additional polymorphisms in ASNS locus in lymphoblastoid cell lines showed that haplotype *1 is diversified in several subtypes of which one was associated with reduced in vitro sensitivity to ASNase (rs10486009, P = 0.01) possibly explaining an association seen in clinical setting. CONCLUSIONS: This finding might have implication for treatment individualization in ALL and other cancers using asparagine depletion strategies. Clin Cancer Res; 21(2); 329-34. ©2014 AACR. See related commentary by Avramis, p. 230.
Assuntos
Antineoplásicos/efeitos adversos , Asparaginase/efeitos adversos , Aspartato-Amônia Ligase/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Antineoplásicos/uso terapêutico , Asparaginase/uso terapêutico , Linhagem Celular Tumoral , Criança , Feminino , Frequência do Gene , Estudos de Associação Genética , Haplótipos , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/enzimologia , Sequências Repetitivas de Ácido NucleicoRESUMO
The steady-state and kinetic properties of the KCNMB3 regulatory subunits associated with calcium-activated potassium channels (BK channels) are presented. BK channels containing four sequence variants (V1-V4) in the four different isoforms of the beta-subunit (beta3a, beta3b, beta3c, and beta3d) were expressed in Xenopus oocytes. Reconstituted BK channel inactivation ranged from none to around 90% inactivation. In particular, channels expressing the beta3b-V4 variant displayed a right shift in the potassium current voltage-dependence of activation and inactivated to about 30% of the maximum conductance, compared with wild-type beta3b channels that showed no inactivation. When the membrane potential was depolarized, BK channels inactivated with a very rapid time course (approximately 2-6 ms). This same variant was previously demonstrated to show subtly higher incidence in patients with idiopathic epilepsy (IE) compared with controls, especially when combined with variant V2 (combined heterozygotes). Furthermore, the gene maps to a region containing a susceptibility factor for this disorder. Taken together, these data suggest that neurons expressing BK channels composed of the beta3b-V4 variant subunit may experience reduced levels of inhibition and may therefore play permissive roles in high levels of neuronal activity that is characteristic of epilepsy.
Assuntos
Variação Genética , Proteínas do Tecido Nervoso/fisiologia , Canais de Potássio Cálcio-Ativados/fisiologia , Canais de Potássio/fisiologia , Subunidades Proteicas/fisiologia , Sequência de Aminoácidos , Animais , Eletrofisiologia/métodos , Feminino , Regulação da Expressão Gênica/fisiologia , Subunidades beta do Canal de Potássio Ativado por Cálcio de Condutância Alta , Canais de Potássio Ativados por Cálcio de Condutância Alta , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Neurônios/química , Neurônios/metabolismo , Oócitos/química , Oócitos/metabolismo , Técnicas de Patch-Clamp , Potássio/metabolismo , Canais de Potássio/biossíntese , Canais de Potássio/genética , Canais de Potássio Cálcio-Ativados/antagonistas & inibidores , Canais de Potássio Cálcio-Ativados/genética , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/fisiologia , Subunidades Proteicas/genética , RNA Mensageiro/biossíntese , Xenopus laevisRESUMO
Short-acting ß2-adrenergic receptor agonists are commonly used bronchodilators for symptom relief in asthmatics. Recent evidence demonstrated that prolonged exposure of cultured airway smooth muscle cells to ß2 agonists directly augments procontractile signaling pathways with the change in expression of regulator of G protein signaling 5 (RGS5). The aim of this study was to test whether genetic variants in RGS5 gene affect the response to short acting ß2-agonists. Bronchodilator responsiveness was assessed in 137 asthmatic children by % change in baseline forced expiratory volume in 1 sec (FEV1 ) after administration of albuterol. The analyses were performed in patients with FEV1 /FVC ratio below 0.9 (FVC-forced vital capacity, n = 99). FEV1 % change adjusted for baseline FEV1 values was significantly different between genotypes of rs10917696 C/T polymorphism (P = 0.008). The association remained significant with inclusion of age, sex, atopy, parental smoking, and controller medications into multivariate model (P = 0.005). We also identified additive effect on the treatment outcome with previously published genetic variant G/A rs1544791 in phosphodiesterase 4 (PDE4D) gene. Carriers of two risk alleles (C and G) had adjusted mean % FEV1 change value 4.6 ± 1.3, while carriers of one and none of the risk alleles had 8.1 ± 0.7% and 13.5 ± 2.4%, respectively, P = 0.001. Our work identifies a new genetic variant in RGS5 demonstrating additive effect with PDE4D, both implicated in modulation of asthma treatment.
Assuntos
Albuterol/uso terapêutico , Asma/tratamento farmacológico , Broncodilatadores/uso terapêutico , Volume Expiratório Forçado/efeitos dos fármacos , Pulmão/fisiopatologia , Proteínas RGS/genética , Adolescente , Asma/genética , Criança , Pré-Escolar , Feminino , Genótipo , Humanos , Pulmão/efeitos dos fármacos , Masculino , Polimorfismo Genético , Resultado do TratamentoRESUMO
PURPOSE: Corticosteroids induce apoptosis in the malignant lymphoid cells and are critical component of combination therapy for acute lymphoblastic leukemia (ALL). Several genome-wide microarray studies showed major implication of proapoptotic Bim in mediating corticosteroid-related resistance in leukemia cells. EXPERIMENTAL DESIGN: We investigated Bim gene polymorphisms and their association with childhood ALL outcome, and the mechanism underlying the observed finding. RESULTS: Lower overall survival (OS) was associated with Bim C29201T located in Bcl-2 homology 3 (BH3) domain (P = 0.01). An association remained significant in multivariate model (P = 0.007), was more apparent in high-risk patients (P = 0.004) and patients treated with dexamethasone (P = 0.009), and was subsequently confirmed in the replication patient cohort (P = 0.03). RNA analysis revealed that C29201T affects generation of γ isoforms (γ1) that lack proapoptotic BH3 domain. The phenotypic effect was minor suggesting the influence of additional factors that may act in conjunction with Bim genotype. Combined analysis with Mcl gene polymorphism (G-486T) revealed profound reduction in OS in individuals with both risk genotypes (P < 0.0005 in discovery and P = 0.002 in replication cohort) and particularly in high-risk patients (P ≤ 0.008). CONCLUSIONS: Increased expression of prosurvival Mcl1 and presence of Bim isoforms lacking proapoptotic function might explain marked reduction of OS in a disease and dose-dependent manner in ALL patients carrying Bim- and Mcl1-risk genotypes.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteínas Reguladoras de Apoptose/genética , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos , Proteínas de Membrana/genética , Polimorfismo Genético/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Proto-Oncogênicas/genética , Proteína 11 Semelhante a Bcl-2 , Western Blotting , Criança , Estudos de Coortes , Dexametasona/administração & dosagem , Feminino , Seguimentos , Humanos , Masculino , Estadiamento de Neoplasias , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Prednisona/administração & dosagem , Prognóstico , Proteínas Proto-Oncogênicas c-bcl-2/genética , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de SobrevidaRESUMO
Childhood acute lymphoblastic leukemia patients (n=310) were analyzed for four SNPs in the NR3C1 gene. Polymorphisms -627A/G, intron 2 +646C/G and 9bT/C were all associated with reduced event-free survival. Haplotypes composed of AGT alleles at these loci and tagged by the intron 2 +646G variant also associated with lower event-free survival (p=0.03). The progressive impact of this haplotype on outcome was seen with two copies associated with reduced overall survival (p=0.05). Quantitative mRNA analysis in lymphoblastoid cell lines showed that carriers of the AGT haplotype had a higher ratio of GR gamma/alpha isoforms (p=0.04), which possibly explains its association with reduced event-free survival and overall survival.
Assuntos
Polimorfismo de Nucleotídeo Único , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Receptores de Glucocorticoides/genética , Linhagem Celular Tumoral , Criança , Pré-Escolar , Feminino , Frequência do Gene , Ligação Genética , Humanos , Lactente , Masculino , Avaliação de Resultados em Cuidados de Saúde , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Prognóstico , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Análise de SobrevidaRESUMO
PURPOSE: To characterize the clinical features and molecular genetic background in a family with various epilepsy phenotypes including febrile seizures, childhood absence epilepsy, and possible temporal lobe epilepsy. METHODS: Clinical data were collected. DNA and RNA were extracted from peripheral blood. A genome-wide microsatellite marker scan was performed and regions with a multipoint location score > or =1.5 were fine mapped. Functional candidate genes identified from databases and by comparing gene expression profiles of genes between affected and unaffected individuals were sequenced. Copy number variation was evaluated with array-based comparative genomic hybridization. RESULTS: The seizure phenotype was benign. Inheritance was consistent with an autosomal dominant model and reduced penetrance. The highest two-point LOD score of 2.8 was identified at marker D17S1606 in a 37cM interval on chromosome 17q12-q24. Loci on 5q11.2 and on 18p11-q11, showed LOD scores > or =1.5 after fine mapping. Sequencing of nine ion-channel genes and two (RPIP8 and SLC25A39) differentially expressed genes from 17q12-q24, as well as IMPA2 from 18p11-q11 did not reveal a pathogenic alteration. No clinically relevant copy number variation was identified. CONCLUSIONS: Our findings suggest complex inheritance of seizure susceptibility in the family with contribution from three loci, including a possible new locus on chromosome 17q. The underlying molecular defects remain unknown.