RESUMO
Endothelin-1 is overexpressed in several tumor types. Activation of the endothelin-A (ETA) receptor may promote cell growth, angiogenesis and invasion, and inhibits the apoptotic process, while activation of the endothelin-B (ETB) receptor may induce cell death by apoptosis and inhibit tumor progression. Hypermethylation and subsequent silencing of the ETB receptor gene promoter has been reported in some cancer types. As the endothelin pathway is subject to research for pharmacological cancer treatment, we investigated the extent of epigenetic deregulation of the ETB receptor gene in non-small cell lung cancer (NSCLC). We scanned 64 NSCLC paired tumor/normal surgical specimens for the ETB receptor promoter for methylation by developing four pyrosequencing assays that covered 24 CpGs. The ETB receptor promoter was significantly hypermethylated in 31 (48%) of tumor samples, presenting considerably higher methylation in 22/24 CpG sites compared with the normal counterpart tissues. ETB receptor mRNA levels were reduced in all lung tumors compared with normal adjacent lung tissue, indicating the potentially important involvement of this gene in lung cancer development. Furthermore, tumor samples with ETB receptor gene methylation tended to have lower receptor mRNA levels compared with unmethylated tumor specimens, suggesting a primary epigenetic role in ETB receptor silencing. Our results point to a significant involvement of ETB receptor epigenetic deregulation in the pathogenesis of lung cancer making the gene a promising candidate biomarker for response to regimens modulating the endothelin axis.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Inativação Gênica , Neoplasias Pulmonares/genética , Receptor de Endotelina B/genética , Sequência de Bases , Metilação de DNA , DNA de Neoplasias/genética , Repetições de Dinucleotídeos/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Dados de Sequência Molecular , Regiões Promotoras Genéticas , RNA Mensageiro/genética , RNA Neoplásico/genéticaRESUMO
Next-generation sequencing (NGS) of circulating tumor DNA (ctDNA) supports blood-based genomic profiling but is not yet routinely implemented in the setting of a phase I trials clinic. TARGET is a molecular profiling program with the primary aim to match patients with a broad range of advanced cancers to early phase clinical trials on the basis of analysis of both somatic mutations and copy number alterations (CNA) across a 641 cancer-associated-gene panel in a single ctDNA assay. For the first 100 TARGET patients, ctDNA data showed good concordance with matched tumor and results were turned round within a clinically acceptable timeframe for Molecular Tumor Board (MTB) review. When a 2.5% variant allele frequency (VAF) threshold was applied, actionable mutations were identified in 41 of 100 patients, and 11 of these patients received a matched therapy. These data support the application of ctDNA in this early phase trial setting where broad genomic profiling of contemporaneous tumor material enhances patient stratification to novel therapies and provides a practical template for bringing routinely applied blood-based analyses to the clinic.
Assuntos
DNA Tumoral Circulante/sangue , DNA Tumoral Circulante/genética , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/genética , Ensaios Clínicos Fase I como Assunto , Variações do Número de Cópias de DNA , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Mutação , Neoplasias/sangue , Neoplasias/genética , Neoplasias/terapia , Seleção de Pacientes , Análise de Sequência de DNARESUMO
AIMS: To investigate the effect of monoamine oxidase A inhibition from a single oral dose of linezolid on the pressor response to intravenous (i.v.) tyramine, using positive and negative controls to validate the methodology. METHODS: This placebo-controlled, three-period crossover study was conducted in 12 healthy male volunteers. Each volunteer received either one oral dose of moclobemide (300 mg), linezolid (600 mg), or placebo tablet followed by an i.v. tyramine pressor test until an increase in systolic blood pressure of at least 30 mmHg above baseline occurred. Each study day was separated by a 7-day washout period. The dose of tyramine required to raise the blood pressure by 30 mmHg (TYR30) was calculated for each oral treatment by linear interpolation between log-transformed doses of i.v. tyramine. The influence of body mass index (BMI) on TYR30 was also investigated. RESULTS: The tyramine sensitivity factor (ratio of the geometric least square mean TYR30 for placebo and active oral treatment) was 1.8 [90% confidence interval (CI) 1.6, 2.0, P < 0.0001] for linezolid and 2.1 (90% CI 1.8, 2.4, P < 0.0001) for the positive control moclobemide. BMI had a statistically significant effect on TYR30. CONCLUSIONS: There was a significant difference in the pressor response to i.v. tyramine between linezolid and placebo. Moclobemide (positive control) and linezolid have a similar pressor response to i.v. tyramine. The statistically significant effect of BMI on TYR30 underlines the advantage of within-individual comparisons of treatments in order to reduce variability and provide more accurate treatment estimates.