Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
1.
Eur Respir J ; 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39231631

RESUMO

BACKGROUND: Airflow limitation is the hallmark of obstructive pulmonary diseases, with the distal airways representing a major site of obstruction. Although numerous in vitro models of bronchi already exist, there is currently no culture system for obstructive diseases that reproduces the architecture and function of small airways. Here, we aimed to engineer a model of distal airways to overcome the limitations of current culture systems. METHODS: We developed a so-called bronchioid model by encapsulating human bronchial adult stem cells derived from clinical samples in a tubular scaffold made of alginate gel. RESULTS: This template drives the spontaneous self-organisation of epithelial cells into a tubular structure. Fine control of the level of contraction is required to establish a model of the bronchiole, which has a physiologically relevant shape and size. 3D imaging, gene expression and single-cell RNA-seq analysis of bronchioids made of bronchial epithelial cells revealed tubular organisation, epithelial junction formation and differentiation into ciliated and goblet cells. Ciliary beating is observed, at a decreased frequency in bronchioids made of cells from COPD patients. The bronchioid can be infected by rhinovirus. An air-liquid interface is introduced that modulates gene expression. CONCLUSION: Here, we provide a proof of concept of a perfusable bronchioid with proper mucociliary and contractile functions. The key advantages of our approach, such as the air‒liquid interface, lumen accessibility, recapitulation of pathological features and possible assessment of clinically relevant endpoints, will make our pulmonary organoid-like model a powerful tool for preclinical studies.

2.
Commun Biol ; 7(1): 184, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38360973

RESUMO

At the early stage of tumor progression, fibroblasts are located at the outer edges of the tumor, forming an encasing layer around it. In this work, we have developed a 3D in vitro model where fibroblasts' layout resembles the structure seen in carcinoma in situ. We use a microfluidic encapsulation technology to co-culture fibroblasts and cancer cells within hollow, permeable, and elastic alginate shells. We find that in the absence of spatial constraint, fibroblasts and cancer cells do not mix but segregate into distinct aggregates composed of individual cell types. However, upon confinement, fibroblasts enwrap cancer cell spheroid. Using a combination of biophysical methods and live imaging, we find that buildup of compressive stress is required to induce fibroblasts spreading over the aggregates of tumor cells. We propose that compressive stress generated by the tumor growth might be a mechanism that prompts fibroblasts to form a capsule around the tumor.


Assuntos
Carcinoma in Situ , Fibroblastos , Humanos , Linhagem Celular Tumoral , Fibroblastos/metabolismo , Esferoides Celulares , Técnicas de Cocultura , Carcinoma in Situ/metabolismo , Carcinoma in Situ/patologia
3.
Bull Cancer ; 109(1): 38-48, 2022 Jan.
Artigo em Francês | MEDLINE | ID: mdl-34996600

RESUMO

Monolayer cultures of cell lines and derived-patient cells have long been the in vitro model of choice in oncology. In particular, these models have made it possible to decipher the mechanisms that determine tumor proliferation and invasion. However these 2D models are insufficient because they do not take into account the spatial organization of cells and their interactions with each other or with the extracellular matrix. In the context of cancer, there is a need to develop new 3D (tumoroid) models in order to gain a better understanding of the development of these pathologies but also to assess the penetration of drugs through a tissue and the associated cellular response. We present here the cell capsule technology (CCT), which allows the production of different tumoroid models: simple or more complex 3D culture models including co-culture of tumor cells with components of the microenvironment (fibroblasts, matrix, etc.). The development of these new 3D culture systems now makes it possible to propose refined physiopathological models that will allow the implementation of improved targeted therapeutic strategies.


Assuntos
Técnicas de Cultura de Células em Três Dimensões/métodos , Encapsulamento de Células/métodos , Organoides , Esferoides Celulares , Alginatos , Fibroblastos Associados a Câncer , Comunicação Celular , Proliferação de Células , Técnicas de Cocultura/métodos , Transição Epitelial-Mesenquimal , Matriz Extracelular/química , Humanos , Invasividade Neoplásica , Células Tumorais Cultivadas , Microambiente Tumoral
4.
Blood Adv ; 5(23): 5372-5386, 2021 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-34555842

RESUMO

Non-Hodgkin B-cell lymphomas (B-NHL) mainly develop within lymph nodes as aggregates of tumor cells densely packed with their surrounding microenvironment, creating a tumor niche specific to each lymphoma subtypes. In vitro preclinical models mimicking biomechanical forces, cellular microenvironment, and 3D organization of B-cell lymphomas remain scarce, while all these parameters are key determinants of lymphomagenesis and drug resistance. Using a microfluidic method based on cell encapsulation inside permeable, elastic, and hollow alginate microspheres, we developed a new tunable 3D model incorporating lymphoma B cells, extracellular matrix (ECM), and/or tonsil stromal cells (TSC). Under 3D confinement, lymphoma B cells were able to form cohesive spheroids resulting from overexpression of ECM components. Moreover, lymphoma B cells and TSC dynamically formed self-organized 3D spheroids favoring tumor cell growth. 3D culture induced resistance to the classical chemotherapeutic agent doxorubicin, but not to the BCL2 inhibitor ABT-199, identifying this approach as a relevant in vitro model to assess the activity of therapeutic agents in B-NHL. RNA-sequence analysis highlighted the synergy of 3D, ECM, and TSC in upregulating similar pathways in malignant B cells in vitro than those overexpressed in primary lymphoma B cells in situ. Finally, our 3D model including ECM and TSC allowed long-term in vitro survival of primary follicular lymphoma B cells. In conclusion, we propose a new high-throughput 3D model mimicking lymphoma tumor niche and making it possible to study the dynamic relationship between lymphoma B cells and their microenvironment and to screen new anti-cancer drugs.


Assuntos
Antineoplásicos , Linfoma de Células B , Linfoma não Hodgkin , Linfócitos B , Proliferação de Células , Humanos , Linfoma de Células B/tratamento farmacológico , Microambiente Tumoral
5.
Front Physiol ; 12: 622615, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33746770

RESUMO

Glioblastoma is among the most common tumor of the central nervous system in adults. Overall survival has not significantly improved over the last decade, even with optimizing standard therapeutic care including extent of resection and radio- and chemotherapy. In this article, we review features of the brain vasculature found in healthy cerebral tissue and in glioblastoma. Brain vessels are of various sizes and composed of several vascular cell types. Non-vascular cells such as astrocytes or microglia also interact with the vasculature and play important roles. We also discuss in vitro engineered artificial blood vessels which may represent useful models for better understanding the tumor-vessel interaction. Finally, we summarize results from clinical trials with anti-angiogenic therapy alone or in combination, and discuss the value of these approaches for targeting glioblastoma.

6.
J Vis Exp ; (158)2020 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-32338647

RESUMO

Two-dimensional (2D) cell cultures do not mimic in vivo tumor growth satisfactorily. Therefore, three-dimensional (3D) culture spheroid models were developed. These models may be particularly important in the field of neuro-oncology. Indeed, brain tumors have the tendency to invade the healthy brain environment. We describe herein an ideal 3D glioblastoma spheroid-based assay that we developed to study tumor invasion. We provide all technical details and analytical tools to successfully perform this assay.


Assuntos
Neoplasias Encefálicas/patologia , Técnicas de Cultura de Células/métodos , Glioblastoma/patologia , Imageamento Tridimensional/métodos , Esferoides Celulares/patologia , Humanos
7.
Nat Commun ; 10(1): 1146, 2019 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-30850588

RESUMO

We undertook a systematic study focused on the matricellular protein Thrombospondin-1 (THBS1) to uncover molecular mechanisms underlying the role of THBS1 in glioblastoma (GBM) development. THBS1 was found to be increased with glioma grades. Mechanistically, we show that the TGFß canonical pathway transcriptionally regulates THBS1, through SMAD3 binding to the THBS1 gene promoter. THBS1 silencing inhibits tumour cell invasion and growth, alone and in combination with anti-angiogenic therapy. Specific inhibition of the THBS1/CD47 interaction using an antagonist peptide decreases cell invasion. This is confirmed by CD47 knock-down experiments. RNA sequencing of patient-derived xenograft tissue from laser capture micro-dissected peripheral and central tumour areas demonstrates that THBS1 is one of the gene with the highest connectivity at the tumour borders. All in all, these data show that TGFß1 induces THBS1 expression via Smad3 which contributes to the invasive behaviour during GBM expansion. Furthermore, tumour cell-bound CD47 is implicated in this process.


Assuntos
Neoplasias Encefálicas/genética , Antígeno CD47/genética , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Proteína Smad3/genética , Trombospondina 1/genética , Fator de Crescimento Transformador beta1/genética , Animais , Neoplasias Encefálicas/irrigação sanguínea , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/patologia , Antígeno CD47/antagonistas & inibidores , Antígeno CD47/metabolismo , Linhagem Celular Tumoral , Córtex Cerebral , Glioblastoma/irrigação sanguínea , Glioblastoma/mortalidade , Glioblastoma/patologia , Humanos , Microdissecção e Captura a Laser , Masculino , Camundongos , Camundongos Knockout , Invasividade Neoplásica , Peptídeos/farmacologia , Regiões Promotoras Genéticas , Ligação Proteica , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Proteína Smad3/metabolismo , Esferoides Celulares/metabolismo , Esferoides Celulares/patologia , Análise de Sobrevida , Trombospondina 1/antagonistas & inibidores , Trombospondina 1/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
8.
Sci Rep ; 7: 42378, 2017 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-28186188

RESUMO

While live 3D high resolution microscopy techniques are developing rapidly, their use for biological applications is partially hampered by practical difficulties such as the lack of a versatile sample chamber. Here, we propose the design of a multi-usage observation chamber adapted for live 3D bio-imaging. We show the usefulness and practicality of this chamber, which we named the UniverSlide, for live imaging of two case examples, namely multicellular systems encapsulated in sub-millimeter hydrogel shells and zebrafish larvae. We also demonstrate its versatility and compatibility with all microscopy devices by using upright or inverted microscope configurations after loading the UniverSlide with fixed or living samples. Further, the device is applicable for medium/high throughput screening and automatized multi-position image acquisition, providing a constraint-free but stable and parallelized immobilization of the samples. The frame of the UniverSlide is fabricated using a stereolithography 3D printer, has the size of a microscopy slide, is autoclavable and sealed with a removable lid, which makes it suitable for use in a controlled culture environment. We describe in details how to build this chamber and we provide all the files necessary to print the different pieces in the lab.

9.
Oncotarget ; 7(42): 68734-68748, 2016 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-27626696

RESUMO

Monoallelic 6p25.3 rearrangements associated with DUSP22 (Dual Specificity Phosphatase 22) gene silencing have been reported in CD30+ peripheral T-cell lymphomas (PTCL), mostly with anaplastic morphology and of cutaneous origin. However, the mechanism of second allele silencing and the putative tumor suppressor function of DUSP22 have not been investigated so far. Here, we show that the presence, in most individuals, of an inactive paralog hampers genetic and epigenetic evaluation of the DUSP22 gene. Identification of DUSP22-specific single-nucleotide polymorphisms haplotypes and fluorescence in situ hybridization and epigenetic characterization of the paralog status led us to develop a comprehensive strategy enabling reliable identification of DUSP22 alterations. We showed that one cutaneous anaplastic large T-cell lymphomas (cALCL) case with monoallelic 6p25.3 rearrangement and DUSP22 silencing harbored exon 1 somatic mutations associated with second allele inactivation. Another cALCL case carried an intron 1 somatic splice site mutation with predicted deleterious exon skipping effect. Other tested PTCL cases with 6p25.3 rearrangement exhibited neither mutation nor deletion nor methylation accounting for silencing of the non-rearranged DUSP22 allele, thus inactivated by a so far unknown mechanism. We also characterized the expression status of four DUSP22 splice variants and found that they are all silenced in cALCL cases with 6p25.3 breakpoints. We finally showed that restoring expression of the physiologically predominant isoform in DUSP22-deficient malignant T cells inhibits cellular expansion by stimulating apoptosis and impairs soft agar clonogenicity and tumorigenicity. This study therefore shows that DUSP22 behaves as a tumor suppressor gene in PTCL.


Assuntos
Fosfatases de Especificidade Dupla/genética , Linfoma de Células T/genética , Fosfatases da Proteína Quinase Ativada por Mitógeno/genética , Polimorfismo de Nucleotídeo Único , Proteínas Supressoras de Tumor/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Processamento Alternativo , Sequência de Aminoácidos , Sequência de Bases , Cromossomos Humanos Par 6/genética , Metilação de DNA , Fosfatases de Especificidade Dupla/metabolismo , Feminino , Rearranjo Gênico , Humanos , Hibridização in Situ Fluorescente , Linfoma Anaplásico de Células Grandes/enzimologia , Linfoma Anaplásico de Células Grandes/genética , Linfoma de Células T/metabolismo , Linfoma Cutâneo de Células T/enzimologia , Linfoma Cutâneo de Células T/genética , Linfoma de Células T Periférico/embriologia , Linfoma de Células T Periférico/genética , Masculino , Pessoa de Meia-Idade , Fosfatases da Proteína Quinase Ativada por Mitógeno/metabolismo , Mutação , Proteínas Supressoras de Tumor/metabolismo
10.
Am J Pathol ; 186(7): 1775-1785, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27181405

RESUMO

Cutaneous T-cell lymphomas (CTCLs) are a heterogeneous group of diseases primarily involving the skin that could have an aggressive course with circulating blood cells, especially in Sézary syndrome and transformed mycosis fungoides. So far, few CTCL cell lines have been adapted for in vivo experiments and their tumorigenicity has not been adequately assessed, hampering the use of a reproducible model for CTCL biological evaluation. In fact, both patient-derived xenografts and cell line xenografts at subcutaneous sites failed to provide a robust tool, because engraftment was dependent on mice strain and cell line subtype. Herein, we describe an original method of intrahepatic injection into adult NOD.Cg-Prkdc(scid)Il2rg(tm1Wjl)/SzJ mice liver of both aggressive (My-La, HUT78, HH, MAC2A, and MAC2B) and indolent (FE-PD and MAC1) CTCL cell lines. Six of the seven CTCL cell lines were grafted with a high rate of success (80%). Moreover, this model provided a quick (15 days) and robust assay for in vivo evaluation of CTCL cell lines tumorigenicity and therapeutic response in preclinical studies. Such a reproducible model can be therefore used for further functional studies and in vivo drug testing.


Assuntos
Linhagem Celular Tumoral/transplante , Fígado , Linfoma Cutâneo de Células T/patologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Animais , Humanos , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos NOD
11.
Blood ; 123(12): 1850-9, 2014 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-24470590

RESUMO

Telomere erosion may be counteracted by telomerase. Here we explored telomere length (TL) and telomerase activity (TA) in primary cutaneous T-cell lymphoma (CTCL) by using quantitative polymerase chain reaction and interphase quantitative fluorescence in situ hybridization assays. Samples from patients with Sézary syndrome (SS), transformed mycosis fungoides (T-MF), and cutaneous anaplastic large cell lymphoma were studied in parallel with corresponding cell lines to evaluate the relevance of TL and TA as target candidates for diagnostic and therapeutic purposes. Compared with controls, short telomeres were observed in aggressive CTCL subtypes such as SS and T-MF and were restricted to neoplastic cells in SS. While no genomic alteration of the hTERT (human telomerase catalytic subunit) locus was observed in patients' tumor cells, TA was detected. To understand the role of telomerase in CTCL, we manipulated its expression in CTCL cell lines. Telomerase inhibition rapidly impeded in vitro cell proliferation and led to cell death, while telomerase overexpression stimulated in vitro proliferation and clonogenicity properties and favored tumor development in immunodeficient mice. Our data indicate that, besides maintenance of TL, telomerase exerts additional functions in CTCL. Therefore, targeting these functions might represent an attractive therapeutic strategy, especially in aggressive CTCL.


Assuntos
Linfoma Cutâneo de Células T/enzimologia , Neoplasias Cutâneas/enzimologia , Telomerase/fisiologia , Homeostase do Telômero/fisiologia , Animais , Estudos de Casos e Controles , Morte Celular , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Xenoenxertos , Humanos , Linfoma Anaplásico de Células Grandes/enzimologia , Linfoma Anaplásico de Células Grandes/genética , Linfoma Cutâneo de Células T/genética , Linfoma Cutâneo de Células T/patologia , Masculino , Camundongos , Camundongos SCID , Micose Fungoide/enzimologia , Micose Fungoide/genética , Transplante de Neoplasias , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , Síndrome de Sézary/enzimologia , Síndrome de Sézary/genética , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Telomerase/antagonistas & inibidores , Telomerase/genética , Homeostase do Telômero/genética
12.
Mod Pathol ; 27(3): 402-11, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24030746

RESUMO

Primary cutaneous large B-cell lymphoma, leg type has been individualized from nodal diffuse large B-cell lymphoma. The objective of this study was to screen primary cutaneous large B-cell lymphoma, leg type for genetic alterations recently described in nodal diffuse large B-cell lymphoma. Skin biopsies from 23 patients were analyzed for IRF4, BCL2, BCL6, and MYC expression. FISH testing was performed for BCL2, BCL6, MYC with separation probes and for CDKN2A and PRDM1/BLIMP1 deletion. Multiple sequential FISH analyses with up to six probes were performed to define samples with multiple cytogenetic alterations. MYD88 mutations were studied by Sanger sequencing. All cases but one displayed at least one genetic alteration (96%). Nine patients exhibited a single genetic mutation and 12 combined several alterations (52%). We observed a split for BCL2, BCL6, or MYC in 1/23, 6/23, and 3/23 of cases, respectively. No double-hit lymphoma was observed. CDKN2A deletion was detected by FISH in only 5/23 cases. BLIMP1 and/or 6q deletion was observed at a higher rate in 10/20 of cases. No correlation between rearrangement and immunohistochemical expression was found for BCL2 or MYC. FISH tracking of sequential hybridizations showed that several alterations were carried by the same nuclei. The p.L265P MYD88 mutation was found in 11/18 (61%) of cases. Contrary to most cutaneous lymphomas that rarely harbor primary genetic alteration of their nodal histological equivalent, primary cutaneous large B-cell lymphoma, leg type seems to be a 'cutaneous counterpart' of activated B-cell-like diffuse large B-cell lymphoma with a similar cytogenetic profile and a high rate of MYD88 oncogenic L265P mutation. This also suggests a common lymphomagenesis with NF-κB activation, strong IRF4 expression and terminal B-cell differentiation blockage. Our data support the use of therapies targeting NF-κB, as most patients displayed disease progression and resistance to conventional therapies.


Assuntos
Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/patologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imuno-Histoquímica , Hibridização in Situ Fluorescente , Estimativa de Kaplan-Meier , Perna (Membro)/patologia , Linfoma Difuso de Grandes Células B/mortalidade , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Neoplasias Cutâneas/mortalidade
13.
Cell Signal ; 24(5): 1074-85, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22261253

RESUMO

EGFR family members are tyrosine kinase transmembrane receptors that, in response to specific extracellular ligands, activate cytoplasmic pathways involved in cell proliferation, migration and differentiation. More recently, a pivotal role for EGF receptors has emerged, through the description of their nuclear localization.We report here the characterization of a nuclear variant of the kinase-defective ErbB3 receptor, ErbB3(80 kDa), spanning the intracytoplasmic domain of the receptor. We assessed the putative transcriptional functions of ErbB3(80 KDa) in cancer cells, through the regulation of the proliferative Cyclin D1 gene, an already known target of the ErbB3 cytoplasmic signaling. We demonstrate here that the binding of ErbB3(80 KDa) on the promoter activates Cyclin D1 transcription and subsequent protein expression, leading to an increased cell proliferation. This mechanism can be balanced in response to the ectopic expression of the tumor suppressor p14ARF that physically interacts with ErbB3(100 kDa) and sequesters it into nucleoli. Our data also show that ErbB3(80 kDa) increases the transcription of proliferative genes even though the cytoplasmic pathways are not activated. This nuclear ErbB3 pathway and the target genes concerned need to be further studied. Indeed, such mechanism could explain the tumor relapse observed in response to treatments aimed at blocking the receptor activation in response to ligand binding.


Assuntos
Proliferação de Células , Ciclina D1/genética , Regiões Promotoras Genéticas , Receptor ErbB-3/metabolismo , Proteína Supressora de Tumor p14ARF/fisiologia , Sequência de Aminoácidos , Linhagem Celular , Núcleo Celular/metabolismo , Ciclina D1/metabolismo , Regulação para Baixo , Regulação da Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde/metabolismo , Humanos , Luciferases de Renilla/biossíntese , Luciferases de Renilla/genética , Dados de Sequência Molecular , Ligação Proteica , Isoformas de Proteínas/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Ativação Transcricional , Proteína Supressora de Tumor p14ARF/metabolismo , Quinases Ativadas por p21/metabolismo
14.
Med Sci (Paris) ; 22(5): 519-24, 2006 May.
Artigo em Francês | MEDLINE | ID: mdl-16687121

RESUMO

The nucleolar Arf protein has initially been shown to regulate cell cycle through the so-called Arf-mdm2-p53 pathway. In addition to this well characterized pathway, convergent data published since 2000 indicate that Arf can inhibit cell proliferation in absence of p53, suggesting the existence of a p53-independent pathway. Several partners have recently been described that could participate in an alternative regulatory process. Recent results show that : (1) Arf binds the rDNA promoter to inhibit the transcription of the 47S rRNA precursor and (2) Arf interacts with the nucleophosmin/B23 protein to negatively regulate rRNA maturation, it is assumed that the tumour suppressor may downregulate the cell cycle progression through the control of ribosome biogenesis, thus resulting in completion of cell cycle arrest.


Assuntos
Proliferação de Células , Ribossomos/fisiologia , Proteína Supressora de Tumor p14ARF/fisiologia , Humanos , RNA Ribossômico/biossíntese
15.
Exp Cell Res ; 312(7): 1185-93, 2006 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-16510138

RESUMO

p16INK4a-pRB-E2F and ARF-MDM2-p53 are two major tumor suppressor networks involved in cell proliferation control. The nucleolar ARF protein binds to MDM2 to activate the growth suppressive functions of p53, but can also exert its tumor suppressor activity independently of p53, through mechanisms involving other regulators: in that manner, p14ARF has been shown to inhibit the transcriptional activity of E2F1 in vitro, suggesting that the two pathways intersect with one another. More recently, ARF has been shown to inhibit ribosomal RNA processing, and to specifically interact with the rRNA promoter, suggesting a role in the regulation of both maturation and transcription processes. We show here that E2F1 can bind the rRNA promoter and modulate its activity through the interaction with two E2F1-binding sequences we have identified. The regulation of ribosome biogenesis appears as a major p53-independent process, which involves both ARF and E2F1 to control cell proliferation.


Assuntos
Fator de Transcrição E2F1/fisiologia , Regulação da Expressão Gênica/fisiologia , Regiões Promotoras Genéticas , RNA Ribossômico/biossíntese , Sequência de Bases , Linhagem Celular Tumoral , Humanos , Dados de Sequência Molecular , RNA Ribossômico/genética , Regulação para Cima
16.
Oncogene ; 24(15): 2580-4, 2005 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-15735732

RESUMO

Both human and murine ARF proteins have been recently reported to impair rRNA maturation and ribosomes biogenesis through a p53-independent pathway. A specific interaction has been established between 5.8S rRNA and the murine p19ARF specie. We report here, by use of both in vitro and ChIP-RNA assays, the absence of any interaction between the human p14ARF and the homologous 5.8S rRNA. Our data are not consistent with the involvement of a 5.8S-p14ARF complex in ribosome biogenesis in man. Rather they suggest that the human protein does not require such an interaction to achieve a similar function. This result is a new argument in favour of functional differences between human and murine ARF proteins.


Assuntos
RNA Ribossômico 5,8S/metabolismo , Proteína Supressora de Tumor p14ARF/farmacologia , Animais , Inibidor p16 de Quinase Dependente de Ciclina , Humanos , Camundongos , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase
17.
Oncogene ; 23(49): 8097-104, 2004 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-15361825

RESUMO

The tumor suppressor Arf (Alternative Reading Frame) protein (p14ARF in human and p19ARF in mouse) is mainly located in the nucleolus consistent with its subcellular localization, the protein has been shown to specifically interact with 5.8S rRNA and with B23/Nucleophosmin and to regulate ribosome biogenesis. Here, we show that the p14ARF protein interacts with chromatin and is recovered by chromatin immunoprecipitation (ChIP) in a fraction that contains a DNA sequence of the rRNA gene promoter. In addition, topoisomerase I (Topo I) that has been shown to interact with p14ARF coprecipitates with p14ARF containing chromatin. These data, in view of the function for Topo I in rRNA transcription, are consistent with a role for the p14ARF-Topo I complex in rRNA transcription and/or maturation.


Assuntos
Cromatina/metabolismo , Genes de RNAr , Regiões Promotoras Genéticas , Proteína Supressora de Tumor p14ARF/fisiologia , DNA Topoisomerases Tipo I/metabolismo , Humanos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA