RESUMO
Latin Americans and Chilean Amerindians have the highest prevalence of gallstone disease (GSD) and gallbladder cancer (GBC) in the world. A handful of loci have been associated with GSD in populations of predominantly European ancestry, however, they only explain a small portion of the genetic component of the disease. Here, we performed a genome-wide association study (GWAS) for GSD in 1,095 admixed Chilean Latinos with Mapuche Native American ancestry. Disease status was assessed by cholecystectomy or abdominal ultrasonography. Top-10 candidate variants surpassing the suggestive cutoff of P < 1 × 10-5 in the discovery cohort were genotyped in an independent replication sample composed of 1,643 individuals. Variants with positive replication were further examined in two European GSD populations and a Chilean GBC cohort. We consistently replicated the association of ABCG8 gene with GSD (rs11887534, P = 3.24 × 10-8, OR = 1.74) and identified TRAF3 (rs12882491, P = 1.11 × 10-7, OR = 1.40) as a novel candidate gene for the disease in admixed Chilean Latinos. ABCG8 and TRAF3 variants also conferred risk to GBC. Gene expression analyses indicated that TRAF3 was significantly decreased in gallbladder (P = 0.015) and duodenal mucosa (P = 0.001) of GSD individuals compared to healthy controls, where according to GTEx data in the small intestine, the presence of the risk allele contributes to the observed effect. We conclude that ABCG8 and TRAF3 genes are associated with GSD and GBC in admixed Latinos and that decreased TRAF3 levels could enhance gallbladder inflammation as is observed in GSD and GSD-associated GBC.
Assuntos
Membro 8 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Neoplasias da Vesícula Biliar/etiologia , Cálculos Biliares/genética , Indígenas Sul-Americanos/genética , Polimorfismo de Nucleotídeo Único , Fator 3 Associado a Receptor de TNF/genética , População Branca/genética , Adulto , Idoso , Chile/etnologia , Colecistectomia , Regulação para Baixo , Duodeno/química , Feminino , Vesícula Biliar/química , Neoplasias da Vesícula Biliar/diagnóstico por imagem , Neoplasias da Vesícula Biliar/etnologia , Neoplasias da Vesícula Biliar/cirurgia , Cálculos Biliares/diagnóstico por imagem , Cálculos Biliares/etnologia , Cálculos Biliares/cirurgia , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Masculino , Pessoa de Meia-Idade , UltrassonografiaRESUMO
Two distantly located promoter regions regulate the dynamic expression of RUNX genes during development: distal P1 and proximal P2 promoters. We have recently described that ß-catenin increases total Runx1 mRNA levels in human CD34(+) hematopoietic progenitors and enhances spatial proximity with its translocation partner ETO. Here, we report that induction of Wnt/ß-catenin signaling in HL60 and Jurkat leukemia-derived cell lines and CD34(+) progenitors selectively activate the production of the longer distal P1-Runx1 mRNA isoform. Gain- and loss-of-function experiments revealed that the differential increase in P1-Runx1 expression is accomplished through a minimal ß-catenin responsive region that includes a highly conserved TCF/LEF-binding element, located -20/-16 bp upstream of the canonical distal P1-Runx1 transcription start site. We conclude that the distal P1-Runx1 promoter is a direct transcriptional target of Wnt/ß-catenin signaling that may be important in normal hematopoiesis or its transition into malignant stem cells during the onset or progression of leukemia.
Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Hematopoese/genética , Células-Tronco Hematopoéticas/metabolismo , Leucemia/genética , Subunidade alfa 2 de Fator de Ligação ao Core/biossíntese , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Células Jurkat , Leucemia/patologia , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Proteína 1 Parceira de Translocação de RUNX1 , Fatores de Transcrição/genética , Via de Sinalização Wnt , beta Catenina/genéticaRESUMO
Chromosomal translocations are frequently associated with a wide variety of cancers, particularly hematologic malignancies. A recurrent chromosomal abnormality in acute myeloid leukemia is the reciprocal translocation t(8;21) that fuses RUNX1 and ETO genes. We report here that Wnt/ß-catenin signaling increases the expression of ETO and RUNX1 genes in human hematopoietic progenitors. We found that ß-catenin is rapidly recruited into RNA polymerase II transcription factories (RNAPII-Ser5) and that ETO and RUNX1 genes are brought into close spatial proximity upon Wnt3a induction. Notably, long-term treatment of cells with Wnt3a induces the generation a frequent RUNX1-ETO translocation event. Thus, Wnt/ß-catenin signaling induces transcription and translocation of RUNX1 and ETO fusion gene partners, opening a novel window to understand the onset/development of leukemia.
Assuntos
Aberrações Cromossômicas , Regulação da Expressão Gênica , Células-Tronco Hematopoéticas/metabolismo , Proteínas de Fusão Oncogênica/genética , Translocação Genética/genética , Proteínas Wnt/genética , beta Catenina/genética , Células Cultivadas , Cromossomos Humanos Par 21/genética , Cromossomos Humanos Par 8/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Imunofluorescência , Células-Tronco Hematopoéticas/citologia , Humanos , Hibridização in Situ Fluorescente , Proteínas Proto-Oncogênicas/genética , RNA Mensageiro/genética , Proteína 1 Parceira de Translocação de RUNX1 , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Fatores de Transcrição/genéticaRESUMO
Transient Receptor Potential Vanilloid type 1 channel (TRPV1) is an important endogenous transducer of noxious heat and chemical stimuli and is required during development of inflammatory hypersensitivity. The transcription factor Runx1 is known to play a relevant role in sensory neuron differentiation as it controls the expression of several sensory nociceptive receptors, including TRPV1. Here, we show that Runx1 up-regulates TRPV1 transcription activity by interacting directly with the proximal TRPV1 gene promoter sequence. Importantly, C/EBPß a well-established heterodimer partner of Runx1 also binds to the TRPV1 promoter and cooperates with Runx1 to further stimulate TRPV1 transcription. Our results support a mechanism where Runx1-C/EBPß-containing transcription regulatory complexes are recruited to the TRPV1 gene promoter to modulate TRPV1 expression in dorsal root ganglia neurons.
Assuntos
Proteína beta Intensificadora de Ligação a CCAAT/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Dor/genética , Canais de Cátion TRPV/genética , Animais , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Gânglios Espinais/metabolismo , Neurônios/metabolismo , Células PC12 , Dor/metabolismo , Regiões Promotoras Genéticas , Ratos , Canais de Cátion TRPV/biossíntese , Canais de Cátion TRPV/metabolismo , Transcrição Gênica , Ativação Transcricional , Regulação para CimaRESUMO
Recent evidence indicates that transcription factor Runx1 modulates the expression of several phenotypic markers in dorsal root ganglia (DRGs) neurons, including the pain-related P2X3 receptor. In several cell lineages C/EBP transcription factors interact with the Runx factor family members to jointly bind and activate transcription of target genes. Here, we examine whether these two transcription factors directly regulate P2X3 gene expression. Through in silico analyses of the first 2 kb of the P2X3 gene promoter we identified putative consensus-binding sites for both Runx1 and C/EBPß transcription factors. Transient over-expression in PC12 cells of either Runx1 or C/EBPß increases P2X3 gene promoter activity and co-expression of both factors results in an additive stimulatory effect on the promoter function. Accordingly, chromatin immunoprecipitation assays demonstrate that both Runx1 and C/EBPß bind to the P2X3 promoter in PC12 cells expressing this gene. Site-directed mutagenesis of the proximal Runx1 and C/EBPß consensus elements in the P2X3 promoter decrease Runx1- and C/EBPß-mediated transcriptional activity. Moreover, C/EBPß-mediated enhancement of the P2X3 promoter requires a functional Runx1 binding site. Altogether our results support a functional and coordinated role for Runx1 and C/EBPß transcription factors during activation of P2X3 gene transcription.