RESUMO
Enhancer profiling is a powerful approach for discovering cis-regulatory elements that define the core transcriptional regulatory circuits of normal and malignant cells. Gene control through enhancer activity is often dominated by a subset of lineage-specific transcription factors. By integrating measures of chromatin accessibility and enrichment for H3K27 acetylation, we have generated regulatory landscapes of chronic lymphocytic leukemia (CLL) samples and representative cell lines. With super enhancer-based modeling of regulatory circuits and assessments of transcription factor dependencies, we discover that the essential super enhancer factor PAX5 dominates CLL regulatory nodes and is essential for CLL cell survival. Targeting enhancer signaling via BET bromodomain inhibition disrupts super enhancer-dependent gene expression with selective effects on CLL core regulatory circuitry, conferring potent anti-tumor activity.
Assuntos
Cromatina/genética , Elementos Facilitadores Genéticos/genética , Regulação Leucêmica da Expressão Gênica/genética , Leucemia Linfocítica Crônica de Células B/genética , Acetilação , Animais , Azepinas/farmacologia , Linhagem Celular Tumoral , Cromatina/efeitos dos fármacos , Cromatina/metabolismo , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Histonas/metabolismo , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/metabolismo , Camundongos Knockout , Fator de Transcrição PAX5/genética , Fator de Transcrição PAX5/metabolismo , Ligação Proteica , Proteínas/antagonistas & inibidores , Proteínas/genética , Proteínas/metabolismo , Triazóis/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
Tumor suppressor genes (TSGs) are commonly inactivated by somatic mutation and/or promoter methylation; yet, recent high-throughput genomic studies have not identified key TSGs inactivated by both mechanisms. We pursued an integrated molecular analysis based on methylation binding domain sequencing (MBD-seq), 450K Methylation arrays, whole exome sequencing, and whole genome gene expression arrays in primary head and neck squamous cell carcinoma (HNSCC) tumors and matched uvulopalatopharyngoplasty tissue samples (UPPPs). We uncovered 186 downregulated genes harboring cancer specific promoter methylation including PAX1 and PAX5 and we identified 10 key tumor suppressor genes (GABRB3, HOXC12, PARP15, SLCO4C1, CDKN2A, PAX1, PIK3AP1, HOXC6, PLCB1, and ZIC4) inactivated by both promoter methylation and/or somatic mutation. Among the novel tumor suppressor genes discovered with dual mechanisms of inactivation, we found a high frequency of genomic and epigenomic alterations in the PAX gene family of transcription factors, which selectively impact canonical NOTCH and TP53 pathways to determine cell fate, cell survival, and genome maintenance. Our results highlight the importance of assessing TSGs at the genomic and epigenomic level to identify key pathways in HNSCC, deregulated by simultaneous promoter methylation and somatic mutations.
Assuntos
Carcinoma de Células Escamosas/genética , Metilação de DNA , Inativação Gênica , Genes Supressores de Tumor , Neoplasias de Cabeça e Pescoço/genética , Regiões Promotoras Genéticas , Carcinoma de Células Escamosas/metabolismo , Linhagem Celular Tumoral , Estudos de Coortes , Ilhas de CpG , Feminino , Neoplasias de Cabeça e Pescoço/metabolismo , Humanos , Masculino , Mutação , Fator de Transcrição PAX5/genética , Fator de Transcrição PAX5/metabolismo , Fatores de Transcrição Box Pareados/genética , Fatores de Transcrição Box Pareados/metabolismo , Receptor Notch1/genética , Receptor Notch1/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
The impact of intermittent fasting versus ad libitum feeding during Salmonella typhimurium infection was evaluated in terms of duodenum IgA levels, bacterial clearance and intestinal and extra-intestinal infection susceptibility. Mice that were intermittently fasted for 12 weeks or fed ad libitum were infected with S. typhimurium and assessed at 7 and 14 days post-infection. Next, we evaluated bacterial load in the faeces, Peyer's patches, spleen and liver by plate counting, as well as total and specific intestinal IgA and plasmatic corticosterone levels (by immunoenzymatic assay) and lamina propria IgA levels in plasma cells (by cytofluorometry). Polymeric immunoglobulin receptor, α- and J-chains, Pax-5 factor, pro-inflammatory cytokine (tumour necrosis factor-α and interferon-γ) and anti-inflammatory cytokine (transforming growth factor-ß) mRNA levels were assessed in mucosal and liver samples (by real-time PCR). Compared with the infected ad libitum mice, the intermittently fasted infected animals had (1) lower intestinal and systemic bacterial loads; (2) higher SIgA and IgA plasma cell levels; (3) higher mRNA expression of most intestinal parameters; and (4) increased or decreased corticosterone levels on day 7 and 14 post-infection, respectively. No contribution of liver IgA was observed at the intestinal level. Apparently, the changes following metabolic stress induced by intermittent fasting during food deprivation days increased the resistance to S. typhimurium infection by triggering intestinal IgA production and presumably, pathogen elimination by phagocytic inflammatory cells.
Assuntos
Duodeno/imunologia , Jejum , Imunoglobulina A/imunologia , Plasmócitos/imunologia , Infecções por Salmonella/imunologia , Salmonella typhimurium/imunologia , Estresse Fisiológico/imunologia , Animais , Carga Bacteriana , Corticosterona/sangue , Citocinas/genética , Citocinas/metabolismo , Duodeno/microbiologia , Fezes/microbiologia , Regulação da Expressão Gênica , Imunidade nas Mucosas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fator de Transcrição PAX5/genética , Fator de Transcrição PAX5/metabolismoRESUMO
BACKGROUND: Despite the weight loss benefits of bariatric surgery, studies have shown considerably compromised nutritional conditions, particularly in relation to bone metabolism, in patients who have undergone this procedure. The goal of this study was evaluate bone metabolism alterations after gastroplasty through the concentrations of carboxy-terminal cross-linking telopeptides of type-I collagen (CTX) and bone-specific alkaline phosphatase (BSAP) and vitamin D status. METHODS: This study, conducted at the Botucatu School of Medicine University Hospital, UNESP, analyzed 22 women with body mass index (BMI) values higher than 35 kg/m(2) who had undergone Roux-en-Y gastric bypass (RYGB) surgery, prior to and 3 and 6 months after the procedure. RESULTS: The patients were evaluated in relation to their anthropometric profile. Obese patients showed a vitamin D status that was compatible with moderate depletion, thus correlating negatively with parathyroid hormone (PTH) and positively with CTX. After surgery, 25-hydroxyvitamin D [25(OH)D] and CTX concentrations increased significantly. Other tests (calcium, phosphorus, magnesium, total AP and BSAP, and PTH) did not differ between the times of analysis and remained stable within the range of normality. Body fat correlated only with 25(OH)D concentrations and was inversely proportional to their increase. There was a positive correlation between PTH and CTX prior to surgery. CONCLUSIONS: Hypovitaminosis D is prevalent in obese individuals, and RYGB is related to CTX increase without BSAP alteration in the first follow-up semester.