RESUMO
In the mouse embryo, the transition from the preimplantation to the postimplantation epiblast is governed by changes in the gene regulatory network (GRN) that lead to transcriptional, epigenetic, and functional changes. This transition can be faithfully recapitulated in vitro by the differentiation of mouse embryonic stem cells (mESCs) to epiblast-like cells (EpiLCs), that reside in naïve and formative states of pluripotency, respectively. However, the GRN that drives this conversion is not fully elucidated. Here we demonstrate that the transcription factor OCT6 is a key driver of this process. Firstly, we show that Oct6 is not expressed in mESCs but is rapidly induced as cells exit the naïve pluripotent state. By deleting Oct6 in mESCs, we find that knockout cells fail to acquire the typical morphological changes associated with the formative state when induced to differentiate. Additionally, the key naïve pluripotency TFs Nanog, Klf2, Nr5a2, Prdm14, and Esrrb were expressed at higher levels than in wild-type cells, indicating an incomplete dismantling of the naïve pluripotency GRN. Conversely, premature expression of Oct6 in naïve cells triggered a rapid morphological transformation mirroring differentiation, that was accompanied by the upregulation of the endogenous Oct6 as well as the formative genes Sox3, Zic2/3, Foxp1, Dnmt3A and FGF5. Strikingly, we found that OCT6 represses Nanog in a bistable manner and that this regulation is at the transcriptional level. Moreover, our findings also reveal that Oct6 is repressed by NANOG. Collectively, our results establish OCT6 as a key TF in the dissolution of the naïve pluripotent state and support a model where Oct6 and Nanog form a double negative feedback loop which could act as an important toggle mediating the transition to the formative state.
Assuntos
Diferenciação Celular , Redes Reguladoras de Genes , Células-Tronco Embrionárias Murinas , Proteína Homeobox Nanog , Animais , Camundongos , Proteína Homeobox Nanog/metabolismo , Proteína Homeobox Nanog/genética , Diferenciação Celular/genética , Células-Tronco Embrionárias Murinas/metabolismo , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Pluripotentes/metabolismo , Células-Tronco Pluripotentes/citologia , Regulação da Expressão Gênica no Desenvolvimento , Fator 3 de Transcrição de Octâmero/metabolismo , Fator 3 de Transcrição de Octâmero/genética , Camadas Germinativas/metabolismo , Camadas Germinativas/citologia , Camundongos KnockoutRESUMO
AKT/PKB is a kinase crucial for pluripotency maintenance in pluripotent stem cells. Multiple post-translational modifications modulate its activity. We have previously demonstrated that AKT1 induces the expression of the pluripotency transcription factor Nanog in a SUMOylation-dependent manner in mouse embryonic stem cells. Here, we studied different cellular contexts and main candidates that could mediate this induction. Our results strongly suggest the pluripotency transcription factors OCT4 and SOX2 are not essential mediators. Additionally, we concluded that this induction takes place in different pluripotent contexts but not in terminally differentiated cells. Finally, the cross-matching analysis of ESCs, iPSCs and MEFs transcriptomes and AKT1 phosphorylation targets provided new clues about possible factors that could be involved in the SUMOylation-dependent Nanog induction by AKT.
Assuntos
Proteínas Proto-Oncogênicas c-akt , Sumoilação , Animais , Camundongos , Proteína Homeobox Nanog/genética , Proteína Homeobox Nanog/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Diferenciação Celular/genética , Fatores de Transcrição/metabolismo , Fator 3 de Transcrição de Octâmero/genética , Proteínas de Homeodomínio/genéticaRESUMO
Background: Ameloblastoma (AME) is characterized by a locally invasive growth pattern. In an attempt to justify the aggressiveness of neoplasms, the investigation of the role of stem cells has gained prominence. The SOX-2, NANOG and OCT4 proteins are important stem cell biomarkers. Methodology: To verify the expression of these proteins in tissue samples of AME, dentigerous cyst (DC) and dental follicle (DF), immunohistochemistry was performed and indirect immunofluorescence were performed on the human AME (AME-hTERT) cell line. Results: Revealed expression of SOX-2, NANOG and OCT4 in the tissue samples and AME-hTERT lineage. Greater immunostaining of the studied proteins was observed in AME compared to DC and DF (p < 0.001). Conclusions: The presence of biomarkers indicates a probable role of stem cells in the genesis and progression of AME.
Assuntos
Ameloblastoma , Células-Tronco Neoplásicas , Humanos , Ameloblastoma/genética , Ameloblastoma/metabolismo , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Proliferação de Células , Imuno-Histoquímica , Proteína Homeobox Nanog/genética , Células-Tronco/metabolismo , Biomarcadores/metabolismo , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Células-Tronco Neoplásicas/metabolismo , Fator 3 de Transcrição de Octâmero/genética , Fator 3 de Transcrição de Octâmero/metabolismoRESUMO
BACKGROUND: Embryonic stem cell markers, such as SOX2, NANOG, and OCT4, are transcription factors expressed in pluripotent stem cells, involved in the mediation of pluripotency and self-renewal. Especially after the discovery of cancer stem cells, these proteins have been associated with several types of neoplasia, including astrocytomas. In the pediatric population, astrocytomas are the most common solid neoplasia and present the highest mortality rates. METHODS: Our study evaluated 5 polymorphisms in SOX2, NANOG, and POU5F1 genes in 101 pediatric astrocytoma samples. RESULTS: We describe the associations between wild and polymorphic alleles in astrocytomas. CONCLUSIONS: In our results, the intronic polymorphic G allele in SOX2 rs77677339 [G/A] had a borderline association with low-grade astrocytomas, and the intronic polymorphic T allele in NANOG rs10845877 [C/T] showed a higher frequency in grade 2, compared to grade 1 astrocytomas, thus showing promising results. IMPACT: Our study is relevant because it shows a potential correlation between polymorphic embryonic stem cell marker genes and pediatric astrocytomas.
Assuntos
Astrocitoma , Proteína Homeobox Nanog , Fatores de Transcrição SOXB1 , Astrocitoma/genética , Criança , Células-Tronco Embrionárias/metabolismo , Humanos , Proteína Homeobox Nanog/genética , Fatores de Transcrição SOXB1/genéticaRESUMO
Connexins (Cxs) are a family of proteins that form two different types of ion channels: hemichannels and gap junction channels. These channels participate in cellular communication, enabling them to share information and act as a synchronized syncytium. This cellular communication has been considered a strong tumor suppressor, but it is now recognized that some type of Cxs can be pro-tumorigenic. For example, Cx46 expression is increased in human breast cancer samples and correlates with cancer stem cell (CSC) characteristics in human glioma. Thus, we explored whether Cx46 and glioma cells, can set up CSC and epithelial-to-mesenchymal transition (EMT) properties in a breast cancer cell line. To this end, we transfected MCF-7 cells with Cx46 attached to a green fluorescent protein (Cx46GFP), and we determined how its expression orchestrates both the gene-expression and functional changes associated with CSC and EMT. We observed that Cx46GFP increased Sox2, Nanog, and OCT4 mRNA levels associated with a high capacity to form monoclonal colonies and tumorspheres. Similarly, Cx46GFP increased the mRNA levels of n-cadherin, Vimentin, Snail and Zeb1 to a higher migratory and invasive capacity. Furthermore, Cx46GFP transfected in MCF-7 cells induced the release of higher amounts of VEGF, which promoted angiogenesis in HUVEC cells. We demonstrated for the first time that Cx46 modulates CSC and EMT properties in breast cancer cells and thus could be relevant in the design of future cancer therapies.
Assuntos
Neoplasias da Mama/genética , Conexinas/genética , Transição Epitelial-Mesenquimal/genética , Células-Tronco Neoplásicas/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Células Endoteliais da Veia Umbilical Humana , Humanos , Células MCF-7 , Proteína Homeobox Nanog/genética , Células-Tronco Neoplásicas/patologia , Fatores de Transcrição SOXB1/genética , Fator A de Crescimento do Endotélio Vascular/genética , Homeobox 1 de Ligação a E-box em Dedo de Zinco/genéticaRESUMO
Persistent infections with some types of human papillomavirus (HPV) constitute the major etiological factor for cervical cancer development. Nanog, a stem cell transcription factor has been shown to increase during cancer progression. We wanted to determine whether Nanog could modulate transcription of E6 and E7 oncogenes. We used luciferase reporters under the regulation of the long control region (LCR) of HPV types 16 and 18 (HPV16/18) and performed RT-qPCR. We found that Nanog increases activity of both viral regulatory regions and elevates endogenous E6/E7 mRNA levels in cervical cancer-derived cells. We demonstrated by in vitro mutagenesis that changes at Nanog-binding sites found in the HPV18 LCR significantly inhibit transcriptional activation. Chromatin immunoprecipitation (ChIP) assays showed that Nanog binds in vivo to the HPV18 LCR, and its overexpression increases its binding as well as that of c-Jun. Surprisingly, we observed that mutation of AP1-binding sites also affect Nanog's ability to activate transcription, suggesting cooperation between the two factors. We searched for putative Nanog-binding sites in the LCR of several HPVs and surprisingly found them only in those types associated with cancer development. Our study shows, for the first time, a role for Nanog in the regulation of E6/E7 transcription of HPV16/18.
Assuntos
Proteínas de Ligação a DNA/genética , Papillomavirus Humano 16/genética , Papillomavirus Humano 18/genética , Proteína Homeobox Nanog/metabolismo , Proteínas Oncogênicas Virais/genética , Proteínas E7 de Papillomavirus/genética , Infecções por Papillomavirus/metabolismo , Proteínas Repressoras/genética , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/metabolismo , Feminino , Regulação Viral da Expressão Gênica , Interações Hospedeiro-Patógeno , Papillomavirus Humano 16/metabolismo , Papillomavirus Humano 18/metabolismo , Humanos , Proteína Homeobox Nanog/genética , Proteínas Oncogênicas Virais/metabolismo , Proteínas E7 de Papillomavirus/metabolismo , Infecções por Papillomavirus/genética , Infecções por Papillomavirus/virologia , Regiões Promotoras Genéticas , Proteínas Repressoras/metabolismo , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo , Ativação Transcricional , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/virologiaRESUMO
ABSTRACT Background Acute lymphoblastic leukemia (ALL) is the most common malignancy in children characterized by the overproduction and accumulation of immature lymphoid cells in the bone marrow and peripheral blood. The BMI-1 is an important component of the Polycomb Repressive Complex-1 (PRC1). It is an important molecule for the self-renewal of hematopoietic stem cells (HSCs). The BMI-1 expression is generally high in HSCs and decreases after cell differentiation. The BMI-1 is required for the maintenance of normal and cancer stem cells and has been reported as an oncogene in various tumors. The NANOG is a homeodomain transcription factor responsible for maintaining the stem cell compartment at the blastocyst stage of developing embryos. The NANOG gene has been proven to be transcribed in CD34+ cells and different leukemic cells. Methods The ribonucleic acid (RNA) was extracted from the peripheral blood mononuclear cells (PBMNCs) of 30 pediatric ALL patients (16 B-ALL and 14 T-ALL) and 14 healthy controls. The Bmi-1 and NANOG expression levels were determined using the quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Results Compared to normal controls, patients with ALL exhibited upregulated levels of Bmi-1 (p = 0.03). Patients who overexpressed Bmi-1 and NANOG displayed a significantly worse survival than low-expressing patients (hazard ratio (HR) 5.74, 95% confidence interval (CI):1.48-22, p = 0.012 and HR 3.8, 95% CI:1.009-14.3, p = 0.048, respectively). Conclusions Taken together, these data suggest that the Bmi-1 and NANOG might serve as a novel survival predictor in ALL patients. Our observation also suggests that the Bmi-1 and NANOG could serve as new therapeutic targets for treatment of pediatric ALL.
Assuntos
Humanos , Masculino , Feminino , Leucemia-Linfoma Linfoblástico de Células Precursoras , Reação em Cadeia da Polimerase em Tempo Real , Proteínas do Grupo Polycomb , Complexo Repressor Polycomb 1 , Proteína Homeobox NanogRESUMO
In embryonic stem (ES) cells, oxidative stress control is crucial for genomic stability, self-renewal, and cell differentiation. Heme oxygenase-1 (HO-1) is a key player of the antioxidant system and is also involved in stem cell differentiation and pluripotency acquisition. We found that the HO-1 gene is expressed in ES cells and induced after promoting differentiation. Moreover, downregulation of the pluripotency transcription factor (TF) OCT4 increased HO-1 mRNA levels in ES cells, and analysis of ChIP-seq public data revealed that this TF binds to the HO-1 gene locus in pluripotent cells. Finally, ectopic expression of OCT4 in heterologous systems repressed a reporter carrying the HO-1 gene promoter and the endogenous gene. Hence, this work highlights the connection between pluripotency and redox homeostasis.
Assuntos
Regulação da Expressão Gênica , Heme Oxigenase-1/genética , Proteínas de Membrana/genética , Células-Tronco Embrionárias Murinas/metabolismo , Fator 3 de Transcrição de Octâmero/genética , Células-Tronco Pluripotentes/metabolismo , RNA Mensageiro/genética , Animais , Benzamidas/farmacologia , Diferenciação Celular/efeitos dos fármacos , Difenilamina/análogos & derivados , Difenilamina/farmacologia , Embrião de Mamíferos , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Heme Oxigenase-1/metabolismo , Luciferases/genética , Luciferases/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/efeitos dos fármacos , Células NIH 3T3 , Proteína Homeobox Nanog/antagonistas & inibidores , Proteína Homeobox Nanog/genética , Proteína Homeobox Nanog/metabolismo , Fator 3 de Transcrição de Octâmero/antagonistas & inibidores , Fator 3 de Transcrição de Octâmero/metabolismo , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/efeitos dos fármacos , Regiões Promotoras Genéticas , Piridinas/farmacologia , Pirimidinas/farmacologia , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Fatores de Transcrição SOXB1/antagonistas & inibidores , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Transdução de Sinais , Transcrição GênicaRESUMO
OBJECTIVES: The promoting roles of cyclin dependent kinase 1 (CDK1) have been revealed in various tumors, however, its effects in the progression of cancer stem cells are still confusing. This work aims to explore the roles of CDK1 in regulating the stemness of lung cancer cells. METHODS: Online dataset analysis was performed to evaluate the correlation between CDK1 exression and the survival of lung cancer patients. RT-qPCR, western blot, cell viability, sphere-formation analysis and ALDH activity detection were used to investigate the roles of CDK1 on lung cancer cell stemness, viability and chemotherapeutic sensitivity. Immunocoprecipitation (Co-IP) analysis and rescuing experiments were performed to reveal the underlying mechanisms contributing to CDK1-mediated effects on lung cancer cell stemness. RESULTS: CDK1 mRNA expression was negatively correlated with the overall survival of lung cancer patients and remarkably increased in tumor spheres formed by lung cancer cells compared to the parental cells. Additionally, CDK1 positively regulated the stemness of lung cancer cells. Mechanistically, CDK1 could interact with Sox2 protein, but not other stemness markers (Oct4, Nanog and CD133). Furthermore, CDK1 increased the phosphorylation, cytoplasm-nuclear translocation and transcriptional activity of Sox2 protein in lung cancer cells. Moreover, CDK1 positively regulated the stemness of lung cancer cells in a Sox2-dependent manner. Finally, we revealed that inhibition of CDK1 enhanced the chemotherapeutic sensitivity, which was also rescued by Sox2 overexpression. CONCLUSIONS: This work reveals a novel CDK1/Sox2 axis responsible for maintaining the stemness of lung cancer cells.