RESUMO
Chromodomain helicase DNA-binding (CHD) chromatin remodelers regulate transcription and DNA repair. They govern cell-fate decisions during embryonic development and are often deregulated in human pathologies. Chd1-8 show upon germline disruption pronounced, often developmental lethal phenotypes. Here we show that contrary to Chd1-8 disruption, Chd9-/-animals are viable, fertile and display no developmental defects or disease predisposition. Germline deletion of Chd9 only moderately affects gene expression in tissues and derived cells, whereas acute depletion in human cancer cells elicits more robust changes suggesting that CHD9 is a highly context-dependent chromatin regulator that, surprisingly, is dispensable for mouse development.
Assuntos
DNA Helicases/genética , Transativadores/genética , Animais , Linhagem Celular , Células Cultivadas , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina , Desenvolvimento Embrionário , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Inativação de Genes , Mutação em Linhagem Germinativa , Humanos , Células K562 , Camundongos , Células-Tronco Embrionárias Murinas/citologiaRESUMO
Wnt/ß-catenin signalling is crucial for maintaining the balance between cell proliferation and differentiation, both during tissue morphogenesis and in tissue maintenance throughout postnatal life. Whereas the signalling activities of the core Wnt/ß-catenin pathway components are understood in great detail, far less is known about the precise role and regulation of the many different modulators of Wnt/ß-catenin signalling that have been identified to date. Here we describe TMEM98, a putative transmembrane protein of unknown function, as an interaction partner and regulator of the GSK3-binding protein FRAT2. We show that TMEM98 reduces FRAT2 protein levels and, accordingly, inhibits the FRAT2-mediated induction of ß-catenin/TCF signalling. We also characterize the intracellular trafficking of TMEM98 in more detail and show that it is recycled between the plasma membrane and the Golgi. Together, our findings not only reveal a new layer of regulation for Wnt/ß-catenin signalling, but also a new biological activity for TMEM98.
Assuntos
Proteínas de Transporte/metabolismo , Membrana Celular/metabolismo , Complexo de Golgi/metabolismo , Proteínas de Membrana/metabolismo , Via de Sinalização Wnt , Animais , Proteínas de Transporte/genética , Membrana Celular/genética , Complexo de Golgi/genética , Células HEK293 , Humanos , Proteínas de Membrana/genética , Camundongos , Transporte Proteico , beta Catenina/genética , beta Catenina/metabolismoRESUMO
Cdkn2ab knockout mice, generated from 129P2 ES cells develop skin carcinomas. Here we show that the incidence of these carcinomas drops gradually in the course of backcrossing to the FVB/N background. Microsatellite analyses indicate that this cancer phenotype is linked to a 20 Mb region of 129P2 chromosome 15 harboring the Wnt7b gene, which is preferentially expressed from the 129P2 allele in skin carcinomas and derived cell lines. ChIPseq analysis shows enrichment of H3K27-Ac, a mark for active enhancers, in the 5' region of the Wnt7b 129P2 gene. The Wnt7b 129P2 allele appears sufficient to cause in vitro transformation of Cdkn2ab-deficient cell lines primarily through CDK6 activation. These results point to a critical role of the Cdkn2ab locus in keeping the oncogenic potential of physiological levels of WNT signaling in check and illustrate that GWAS-based searches for cancer predisposing allelic variants can be enhanced by including defined somatically acquired lesions as an additional input.
Assuntos
Carcinogênese/genética , Inibidor de Quinase Dependente de Ciclina p15/deficiência , Inibidor p16 de Quinase Dependente de Ciclina/deficiência , Variação Genética , Neoplasias Cutâneas/genética , Via de Sinalização Wnt/genética , Alelos , Animais , Pareamento de Bases/genética , Linhagem Celular Tumoral , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Cromossomos de Mamíferos/genética , Quinase 6 Dependente de Ciclina/metabolismo , Inibidor de Quinase Dependente de Ciclina p15/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Fibroblastos/metabolismo , Ligação Genética , Pulmão/patologia , Metaplasia , Camundongos Knockout , Fator de Crescimento Derivado de Plaquetas/metabolismoRESUMO
Lung squamous cell carcinoma (LSCC) is a devastating malignancy with no effective treatments, due to its complex genomic profile. Therefore, preclinical models mimicking its salient features are urgently needed. Here we describe mouse models bearing various combinations of genetic lesions predominantly found in human LSCC. We show that SOX2 but not FGFR1 overexpression in tracheobronchial basal cells combined with Cdkn2ab and Pten loss results in LSCC closely resembling the human counterpart. Interestingly, Sox2;Pten;Cdkn2ab mice develop LSCC with a more peripheral location when Club or Alveolar type 2 (AT2) cells are targeted. Our model highlights the essential role of SOX2 in commanding the squamous cell fate from different cells of origin and represents an invaluable tool for developing better intervention strategies.
Assuntos
Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Fatores de Transcrição SOXB1/genética , Animais , Carcinoma de Células Escamosas/metabolismo , Proliferação de Células/genética , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/metabolismo , Camundongos , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/biossíntese , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Transcrição Gênica , Microambiente TumoralRESUMO
Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumor, and no effective treatment is available to date. Mouse models of SCLC based on the inactivation of Rb1 and Trp53 show frequent amplifications of the Nfib and Mycl genes. Here, we report that, although overexpression of either transcription factor accelerates tumor growth, NFIB specifically promotes metastatic spread. High NFIB levels are associated with expansive growth of a poorly differentiated and almost exclusively E-cadherin (CDH1)-negative invasive tumor cell population. Consistent with the mouse data, we find that NFIB is overexpressed in almost all tested human metastatic high-grade neuroendocrine lung tumors, warranting further assessment of NFIB as a tumor progression marker in a clinical setting.
