RESUMO
Genome-wide association studies (GWAS) have identified many disease-associated variants, yet mechanisms underlying these associations remain unclear. To understand obesity-associated variants, we generate gene regulatory annotations in adipocytes and hypothalamic neurons across cellular differentiation stages. We then test variants in 97 obesity-associated loci using a massively parallel reporter assay and identify putatively causal variants that display cell type specific or cross-tissue enhancer-modulating properties. Integrating these variants with gene regulatory information suggests genes that underlie obesity GWAS associations. We also investigate a complex genomic interval on 16p11.2 where two independent loci exhibit megabase-range, cross-locus chromatin interactions. We demonstrate that variants within these two loci regulate a shared gene set. Together, our data support a model where GWAS loci contain variants that alter enhancer activity across tissues, potentially with temporally restricted effects, to impact the expression of multiple genes. This complex model has broad implications for ongoing efforts to understand GWAS.
Assuntos
Adipócitos/fisiologia , Elementos Facilitadores Genéticos , Pleiotropia Genética , Obesidade/genética , Adipócitos/citologia , Arritmias Cardíacas/genética , Arritmias Cardíacas/patologia , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/patologia , Estudo de Associação Genômica Ampla , Gigantismo/genética , Gigantismo/patologia , Cardiopatias Congênitas/genética , Cardiopatias Congênitas/patologia , Humanos , Hipotálamo/fisiologia , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , MAP Quinase Quinase 5/genética , Neurônios/citologia , Neurônios/fisiologia , Polimorfismo de Nucleotídeo Único , Proteínas Quinases/genética , Locos de Características Quantitativas , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , Fatores de Transcrição/genética , TranscriptomaRESUMO
Mitogen/extracellular signal-regulated kinase-5 (MEK5)/extracellular signal-regulated protein kinase-5 (ERK5) pathway plays a pro-oncogenic role in tumourigenesis by anticell apoptosis, promoting cell proliferation and differentiation in response to extracellular stimuli. As overexpressed MEK5/ERK5 is involved in the development of lung cancer, we hypothesised that the single nucleotide polymorphisms (SNPs) in MEK5 and ERK5 genes may influence gene expression and thus be associated with lung cancer risk. Five putative functional polymorphisms (rs3743353T>C, rs7172582C>T and rs2278076A>G of MEK5 and rs3866958G>T and rs2233083C>T of ERK5) were genotyped in two independent case-control studies with a total of 1559 lung cancer patients and 1679 controls in southern and eastern Chinese population. We found the rs3866958G>T of ERK5 was significantly associated with lung cancer risk, while other SNPs were not. Compared with the rs3866958TG/TT genotypes, the GG genotype conferred an increased risk of lung cancer (odds ratio = 1.30, 95% confidence interval = 1.12-1.51, P = 5.0×10(-4)), and this effect was more pronounced in smokers, accompanying with a significant interaction with smoking (P interaction = 0.013). The GG genotype also had significant higher mRNA levels of ERK5 in lung cancer tissues than TG/TT genotypes (P = 1.0×10(-4)); the luciferase reporter with the G allele showed significant higher transcription activities than the T allele, especially after the treatment with tobacco extract in vitro. Our data indicated that the functional polymorphism rs3866958G>T in ERK5 was associated with an increased lung cancer risk in smokers by virtue of the positive interaction with smoking on promoting the ERK5 expression, which might be a valuable indicator for predicting lung cancer risk in smokers.
Assuntos
Neoplasias Pulmonares/genética , Proteína Quinase 7 Ativada por Mitógeno/genética , Polimorfismo de Nucleotídeo Único , Fumar/efeitos adversos , Povo Asiático/genética , Estudos de Casos e Controles , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Interação Gene-Ambiente , Predisposição Genética para Doença , Humanos , Luciferases/genética , Neoplasias Pulmonares/etiologia , MAP Quinase Quinase 5/genética , Masculino , Pessoa de Meia-Idade , Extratos Vegetais/farmacologia , Regiões Promotoras Genéticas , Fumar/genéticaRESUMO
BACKGROUND: Aberrant mitogen/extracellular signal-regulated kinase 5 (MEK5)-extracellular signal-regulated protein kinase 5 (ERK5)-mediated signalling has been implicated in a number of tumour types including prostate cancer (PCa). The molecular basis of ERK5-driven carcinogenesis and its clinical relevance remain to be fully characterised. METHODS: Modulation of ERK5 expression or function in human PCa PC3 and PC3-ERK5 (stably transfected with ERK5) cells was performed using siRNA-mediated knockdown or the MEK inhibitor PD18435 respectively. In vitro significance of ERK5 signalling was assessed by assays for proliferation, motility, invasion and invadopodia. Expression of matrix metalloproteinases/tissue inhibitors of metalloproteases was determined by Q-RT-PCR. Extracellular signal-regulated protein kinase 5 expression in primary and metastatic PCa was examined using immunohistochemistry. RESULTS: Reduction of ERK5 expression or signalling significantly inhibited the motility and invasive capability of PC3 cells. Extracellular signal-regulated protein kinase 5-mediated signalling significantly promoted formation of in vivo metastasis in an orthotopic PCa model (P<0.05). Invadopodia formation was also enhanced by forced ERK5 expression in PC3 cells. Furthermore, in metastatic PCa, nuclear ERK5 immunoreactivity was significantly upregulated when compared with benign prostatic hyperplasia and primary PCa (P=0.013 and P<0.0001, respectively). CONCLUSION: Our in vitro, in vivo and clinical data support an important role for the MEK5-ERK5 signalling pathway in invasive PCa, which represents a potential target for therapy in primary and metastatic PCa.