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1.
Histopathology ; 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31173643

RESUMO

AIMS: Mantle cell lymphoma (MCL) is a heterogeneous disease with an aggressive behaviour in most cases, which is associated with expression of sex determining region-Y-box11 (SOX11). Experimental studies have shown that SOX11 expression is associated with an angiogenic switch characterised by increased expression of angiogenic-related signatures and vascularisation of murine tumours. However, the relationship between angiogenesis and SOX11 expression in primary tumours is not well understood. Therefore, the aim of this study was to evaluate the development of microvascular angiogenesis in primary MCL in relation to SOX11 expression and its potential prognostic value. METHODS AND RESULTS: Fifty-six patients diagnosed with MCL, 38 SOX11-positive and 18 SOX11-negative, were studied. The relative intratumoral microvascular area (MVA) and microvessel density (MVD) (number of intratumoral microvessels/µm2 ) were measured on CD34-stained slides using a computerised image analysis system. SOX11-positive MCL showed a significant higher microvascular development than negative tumours (median MVA = 14.5 × 10-3 versus 5.0 × 10-3 P < 0.001; median MVD = 18.6/µm2 versus 14.2/µm2 , P = 0.021). Analysing the MVA and MVD as continuous variables, a high MVD was associated with shorter overall survival (P = 0.004), and a similar tendency was observed for high MVA (P = 0.064). The microvascular development was not related to the Ki-67 proliferative index or 17p/TP53, 9p or 11q alterations. CONCLUSIONS: These findings suggest that SOX11 promotes an angiogenic phenotype in primary MCL, which may contribute to the more aggressive behaviour of these tumours.

2.
Int J Cancer ; 2018 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-30468254

RESUMO

The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib has been shown to be highly effective in patients with chronic lymphocytic leukemia (CLL) and is approved for CLL treatment. Unfortunately, resistance and intolerance to ibrutinib has been observed in several studies, opening the door for more specific BTK inhibitors. CC-292 (spebrutinib) is a BTK inhibitor with increased specificity for BTK and less inhibition of other kinases. Our in vitro studies showed that CC-292 potently inhibited B-cell receptor signaling, activation, proliferation and chemotaxis of CLL cells. In in vivo studies using the adoptive transfer TCL1 mouse model of CLL, CC-292 reduced tumor load and normalized tumor-associated expansion of T cells and monocytes, while not affecting T cell function. Importantly, the combination of CC-292 and bendamustine impaired CLL cell proliferation in vivo and enhanced the control of CLL progression. Our results demonstrate that CC-292 is a specific BTK inhibitor with promising performance in combination with bendamustine in CLL. Further clinical trials are warranted to investigate the therapeutic efficacy of this combination regimen. This article is protected by copyright. All rights reserved.

3.
Nat Commun ; 9(1): 4973, 2018 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-30478318

RESUMO

USP25 deubiquitinating enzyme is a key member of the ubiquitin system, which acts as a positive regulator of the Wnt/ß-catenin signaling by promoting the deubiquitination and stabilization of tankyrases. USP25 is characterized by the presence of a long insertion in the middle of the conserved catalytic domain. The crystal structure of USP25 displays an unexpected homotetrameric quaternary assembly that is directly involved in the inhibition of its enzymatic activity. The tetramer is assembled by the association of two dimers and includes contacts between the coiled-coil insertion domain and the ubiquitin-binding pocket at the catalytic domain, revealing a distinctive autoinhibitory mechanism. Biochemical and kinetic assays with dimer, tetramer and truncation constructs of USP25 support this mechanism, displaying higher catalytic activity in the dimer assembly. Moreover, the high stabilization of tankyrases in cultured cells by ectopic expression of a constitutive dimer of USP25 supports a biological relevance of this tetramerization/inhibition mechanism.

4.
Curr Opin Hematol ; 25(4): 299-306, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29738333

RESUMO

PURPOSE OF REVIEW: SOX11 has emerged as a key transcription factor in the pathogenesis of mantle cell lymphoma (MCL) whereas it is not expressed in normal B cells or virtually in any other mature B-cell neoplasm. This review will examine the role of SOX11 as a biomarker in MCL, the new information on its transcriptional targets, and the mechanisms regulating its expression in MCL. RECENT FINDINGS: SOX11 is highly expressed in conventional MCL, including cyclin D1-negative cases, but it is not expressed in the indolent leukemic nonnodal MCL subtype. These two MCL subtypes also differ in their cell-of-origin, IGHV mutational status and genomic instability. SOX11 promotes tumor growth of MCL cells in vivo and regulates a broad transcriptional program that includes B-cell differentiation pathways and tumor-microenvironment interactions, among others. The mechanisms upregulating SOX11 in MCL are not well understood but are mediated in part by the three-dimensional reconfiguration of the DNA, bringing together a distant enhancer region and the SOX11 promoter. SUMMARY: SOX11 is a relevant element in the pathogenesis of MCL and has been instrumental to identify two distinct clinicobiological subtypes of this tumor. Further studies should clarify the mechanisms mediating its oncogenic potential and leading to its intriguing expression in these tumors.

5.
Blood ; 130(4): 501-513, 2017 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-28533307

RESUMO

SOX11 overexpression in mantle cell lymphoma (MCL) has been associated with more aggressive behavior and worse outcome. However, SOX11 oncogenic pathways driving MCL tumor progression are poorly understood. Here, we demonstrate that SOX11 binds to regulatory regions of 2 important genes for microenvironment signals in cancer: (C-X-C motif) chemokine receptor 4 (CXCR4) and PTK2 (encoding for focal adhesion kinase [FAK]). Moreover, SOX11+ xenograft and human primary MCL tumors overexpress cell migration and stromal stimulation gene signatures compared with their SOX11- counterparts. We show that SOX11 directly upregulates CXCR4 and FAK expression, activating PI3K/AKT and ERK1/2 FAK-downstream pathways in MCL. Concordantly, SOX11+ MCL cells have higher cell migration, transmigration through endothelial cells, adhesion to stromal cells, and cell proliferation and display an increased resistance to conventional drug therapies compared with SOX11- MCL cells. Specific FAK inhibition blocks downstream PI3K/AKT- and ERK1/2-mediated phosphorylation. Additionally, specific FAK and PI3K inhibitors reduce SOX11-enhanced MCL cell migration and stromal interactions and revert cell adhesion-mediated drug resistance (CAM-DR) to the same levels as SOX11- MCL cells. In intravenous MCL xenograft models, SOX11+ MCL cells display higher cell migration, invasion, and growth compared with SOX11-knockdown cells, and specific FAK and CXCR4 inhibitors impair SOX11-enhanced MCL engraftment in bone marrow. Overall, our results suggest that SOX11 promotes MCL homing and invasion and increases CAM-DR through the direct regulation of CXCR4 and FAK expression and FAK/PI3K/AKT pathway activation, contributing to a more aggressive phenotype. Inhibition of this pathway may represent an efficient strategy to overcome stromal-mediated chemotherapy refractoriness in aggressive MCL.


Assuntos
Quinase 1 de Adesão Focal/metabolismo , Linfoma de Célula do Manto/metabolismo , Receptores CCR4/metabolismo , Fatores de Transcrição SOXC/metabolismo , Transdução de Sinais , Microambiente Tumoral , Animais , Linhagem Celular Tumoral , Quinase 1 de Adesão Focal/genética , Células HEK293 , Células Endoteliais da Veia Umbilical Humana , Humanos , Linfoma de Célula do Manto/genética , Linfoma de Célula do Manto/patologia , Camundongos , Camundongos SCID , Invasividade Neoplásica , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores CCR4/genética , Fatores de Transcrição SOXC/genética
6.
Curr Oncol Rep ; 19(6): 43, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28466437

RESUMO

Mantle cell lymphoma (MCL) is an aggressive lymphoid neoplasm, incurable with current therapies. The t(11;14)(q13;q32) involving cyclin D1 is considered the first oncogenic hit found in virtually all MCLs. However, additional secondary genomic alterations are essential for complete transformation. MCLs are genetically very unstable with several genetic alterations associated with its high proliferative behavior involving several oncogenic pathways. Furthermore, SOX11 is overexpressed in the majority of conventional MCLs (cMCL), including cyclin D1-negative cases, but absent in non-nodal leukemic MCL with indolent clinical behavior (nnMCL). Recent data have revealed the potential oncogenic role of SOX11 in MCL biology, highlighting its implication in tumor aggressiveness and progression. This review addresses the implication of SOX11 overexpression and frequent genetic lesions, cooperating with cyclin D1 underlying the pathogenesis of this aggressive disease.


Assuntos
Ciclina D1/metabolismo , Linfoma de Célula do Manto/genética , Linfoma de Célula do Manto/metabolismo , Fatores de Transcrição SOXC/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinogênese , Humanos , Imuno-Histoquímica , Linfoma de Célula do Manto/patologia
7.
Mod Pathol ; 28(11): 1435-47, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26360498

RESUMO

Mantle cell lymphoma is a mature lymphoid neoplasm characterized by the t(11;14)(q13;q32) and cyclin D1 overexpression. SOX11 is a transcription factor commonly overexpressed in these tumors but absent in most other mature B-cell lymphomas whose function is not well understood. Experimental studies have shown that silencing of SOX11 in mantle cell lymphoma cells promotes the shift from a mature B cell into an early plasmacytic differentiation phenotype, suggesting that SOX11 may contribute to tumor development by blocking the B-cell differentiation program. The relationship between SOX11 expression and terminal B-cell differentiation in primary mantle cell lymphoma and its relationship to the plasmacytic differentiation observed in occasional cases is not known. In this study we have investigated the terminal B-cell differentiation phenotype in 60 mantle cell lymphomas, 41 SOX11-positive and 19 SOX11-negative. Monotypic plasma cells and lymphoid cells with plasmacytic differentiation expressing cyclin D1 were observed in 7 (37%) SOX11-negative but in none of 41 SOX11-positive mantle cell lymphomas (P<0.001). Intense cytoplasmic expression of a restricted immunoglobulin light chain was significantly more frequent in SOX11-negative than -positive tumors (58 vs 13%) (P=0.001). Similarly, BLIMP1 and XBP1 expression was also significantly more frequent in SOX11-negative than in -positive cases (83 vs 34% and 75 vs 11%, respectively) (P=0.001). However, no differences in the expression of IRF4/MUM1 were observed among these subtypes of mantle cell lymphoma. In conclusion, these results indicate that SOX11-negative mantle cell lymphoma may be a particular subtype of this tumor characterized by more frequent morphological and immunophenotypic terminal B-cell differentiation features that may be facilitated by the absence of SOX11 transcription factor.


Assuntos
Linfócitos B/patologia , Diferenciação Celular , Linfoma de Célula do Manto/patologia , Plasmócitos/patologia , Fatores de Transcrição SOXC/biossíntese , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Linfoma de Célula do Manto/imunologia , Linfoma de Célula do Manto/metabolismo , Masculino , Pessoa de Meia-Idade , Fatores de Transcrição SOXC/imunologia
8.
Leuk Lymphoma ; 56(4): 866-76, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25015778

RESUMO

Mantle cell lymphoma (MCL) is a distinct subtype of malignant lymphoma which is characterized by the chromosomal translocation t(11;14)(q13;q32) resulting in constitutional overexpression of cyclin D1 and cell cycle dysregulation in almost all cases. Clinically, MCL shows an aggressive clinical course with a continuous relapse pattern and a median survival of only 3-5 years. However, recently a subset of 15% long-term survivors has been identified with a rather indolent clinical course. Targeted strategies include the proteasome inhibitors, immune modulatory drugs (IMiDs), mammalian target of rapamycin (mTOR) inhibitors and especially inhibitors of the B-cell receptor pathway. Our recent annual conference focused on the molecular pathogenesis of the disease and how these underlying molecular alterations may guide the selection and integration of innovative approaches for therapy. This review of the meeting covers in particular the identification of indolent cases, and deals with the role of the B-cell receptor pathway in MCL, as well as the detection of minimal residual disease and implementation of molecular approaches in current clinical trials.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma de Célula do Manto/genética , Linfoma de Célula do Manto/terapia , Terapia de Alvo Molecular/métodos , Transplante de Células-Tronco/métodos , Cromossomos Humanos Par 11/genética , Cromossomos Humanos Par 14/genética , Humanos , Terapia de Alvo Molecular/tendências , Neoplasia Residual/diagnóstico , Neoplasia Residual/genética , Análise de Sobrevida , Translocação Genética , Resultado do Tratamento
9.
Blood ; 124(14): 2235-47, 2014 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-25092176

RESUMO

SOX11 is overexpressed in several solid tumors and in the vast majority of aggressive mantle cell lymphomas (MCLs). We have recently proven that SOX11 silencing reduces tumor growth in a MCL xenograft model, consistent with the indolent clinical course of the human SOX11-negative mantle cell lymphoma (MCL). However, the direct oncogenic mechanisms and downstream effector pathways implicated in SOX11-driven transformation remain poorly understood. Here, we observed that SOX11-positive xenograft and human primary MCL tumors overexpressed angiogenic gene signatures and had a higher microvascular density compared with their SOX11-negative counterparts. Conditioned media of SOX11-positive MCL cell lines induced in vitro endothelial cell proliferation, migration, tube formation, and activation of downstream angiogenic pathways. We identified PDGFA as a SOX11 direct target gene upregulated in MCL cells whose inhibition impaired SOX11-enhanced in vitro angiogenic effects on endothelial cells. In addition, platelet-derived growth factor A (PDGFA) was overexpressed in SOX11-positive but not in SOX11-negative MCL. In vivo, imatinib impaired tumor angiogenesis and lymphoma growth in SOX11-positive MCL xenograft tumors. Overall, our results demonstrate a prominent role for SOX11 as a driver of proangiogenic signals in MCL, and highlight the SOX11-PDGFA axis as a potential therapeutic target for the treatment of this aggressive disease.


Assuntos
Regulação Neoplásica da Expressão Gênica , Linfoma de Célula do Manto/metabolismo , Fator de Crescimento Derivado de Plaquetas/metabolismo , Fatores de Transcrição SOXC/metabolismo , Animais , Movimento Celular , Proliferação de Células , Meios de Cultivo Condicionados/química , Células Endoteliais/citologia , Perfilação da Expressão Gênica , Inativação Gênica , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos , Camundongos SCID , Transplante de Neoplasias , Neovascularização Patológica , Proteômica , Transdução de Sinais , Ativação Transcricional
10.
Am J Surg Pathol ; 38(1): 86-93, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24145648

RESUMO

The diagnosis of mantle cell lymphoma (MCL) can be difficult, especially when no t(11;14) translocation and cyclin D1 overexpression can be detected. In such cases, the transcription factor SOX11 represents an important diagnostic marker, as it is expressed in most MCLs and, in particular, in all cyclin D1-negative MCLs reported so far. A reliable anti-SOX11 antibody is therefore a very useful tool for routine diagnosis. Here, we characterize the new monoclonal anti-SOX11 antibodies, suitable for Western blot assay and immunohistochemistry (IHC) on formalin-fixed paraffin-embedded tissue; we tested them on a large series of primary lymphoid tumors and compared these results with those of other routinely used antibodies. Moreover, we show that IHC results depend on transcription levels of SOX11, which suggests that posttranscriptional and posttranslational modifications do not significantly affect cutoff levels for IHC detection of SOX11.


Assuntos
Anticorpos Monoclonais , Biomarcadores Tumorais/análise , Imuno-Histoquímica , Linfoma de Célula do Manto/química , Fatores de Transcrição SOXC/análise , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/imunologia , Western Blotting , Ciclina D1/análise , Regulação Neoplásica da Expressão Gênica , Humanos , Hibridização in Situ Fluorescente , Linfoma de Célula do Manto/genética , Linfoma de Célula do Manto/imunologia , Linfoma de Célula do Manto/patologia , Valor Preditivo dos Testes , Prognóstico , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição SOXC/genética , Fatores de Transcrição SOXC/imunologia , Transcrição Genética
11.
Proc Natl Acad Sci U S A ; 110(45): 18250-5, 2013 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-24145436

RESUMO

Mantle cell lymphoma (MCL) is an aggressive tumor, but a subset of patients may follow an indolent clinical course. To understand the mechanisms underlying this biological heterogeneity, we performed whole-genome and/or whole-exome sequencing on 29 MCL cases and their respective matched normal DNA, as well as 6 MCL cell lines. Recurrently mutated genes were investigated by targeted sequencing in an independent cohort of 172 MCL patients. We identified 25 significantly mutated genes, including known drivers such as ataxia-telangectasia mutated (ATM), cyclin D1 (CCND1), and the tumor suppressor TP53; mutated genes encoding the anti-apoptotic protein BIRC3 and Toll-like receptor 2 (TLR2); and the chromatin modifiers WHSC1, MLL2, and MEF2B. We also found NOTCH2 mutations as an alternative phenomenon to NOTCH1 mutations in aggressive tumors with a dismal prognosis. Analysis of two simultaneous or subsequent MCL samples by whole-genome/whole-exome (n = 8) or targeted (n = 19) sequencing revealed subclonal heterogeneity at diagnosis in samples from different topographic sites and modulation of the initial mutational profile at the progression of the disease. Some mutations were predominantly clonal or subclonal, indicating an early or late event in tumor evolution, respectively. Our study identifies molecular mechanisms contributing to MCL pathogenesis and offers potential targets for therapeutic intervention.


Assuntos
Evolução Clonal/genética , Variação Genética , Genoma Humano/genética , Linfoma de Célula do Manto/genética , Mutação/genética , Proteínas Mutadas de Ataxia Telangiectasia/genética , Sequência de Bases , Ciclina D1/genética , Estudo de Associação Genômica Ampla , Genômica/métodos , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Linfoma de Célula do Manto/fisiopatologia , Análise em Microsséries , Dados de Sequência Molecular , Receptor Notch2/genética , Receptor 2 Toll-Like/genética
12.
Clin Cancer Res ; 19(12): 3121-9, 2013 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-23640973

RESUMO

PURPOSE: microRNAs (miRNA) are posttranscriptional gene regulators that may be useful as diagnostic and/or prognostic biomarkers. We aim to study the expression profiles of a high number of miRNAs and their relationship with clinicopathologic and biologic relevant features in leukemic mantle cell lymphomas (MCL). EXPERIMENTAL DESIGN: Expression profiling of 664 miRNAs was investigated using a high-throughput quantitative real-time PCR platform in 30 leukemic MCLs. Statistical and bioinformatic analyses were conducted to define miRNAs associated with different clinicopathologic parameters. Gene expression profiling was investigated by microarrays in 16 matching cases to study the potential genes and pathways targeted by selected miRNAs. The prognostic value of miR-34a was investigated in 2 independent series of 29 leukemic and 50 nodal MCLs. RESULTS: Robust consensus clustering defined 2 main MCL subgroups with significant differences in the immunoglobulin (IGHV) mutational status, SOX11 expression, genomic complexity, and nodal clinical presentation. Supervised analyses of IGHV and SOX11 categories identified 17 and 22 miRNAs differentially expressed, respectively. Enriched targets of these miRNAs corresponded to relevant pathways in MCL pathogenesis such as DNA stress response, CD40 signaling, and chromatin modification. In addition, we found 7 miRNAs showing prognostic significance independently of IGHV status and SOX11 expression. Among them, miR-34a was also associated with poor prognosis in 2 independent series of leukemic and nodal MCL, and in cooperation with high expression of the MYC oncogene. CONCLUSION: We have identified miRNAs and target pathways related to clinical and biologic variants of leukemic MCL, and validated miR-34a as a prognostic marker in MCL.


Assuntos
Imunoglobulinas/genética , Linfonodos/patologia , Linfoma de Célula do Manto/patologia , MicroRNAs/biossíntese , Fatores de Transcrição SOXC/biossíntese , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Linfoma de Célula do Manto/genética , Linfoma de Célula do Manto/metabolismo , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Mutação , Prognóstico , Transdução de Sinais/genética
13.
Blood ; 121(12): 2175-85, 2013 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-23321250

RESUMO

Mantle cell lymphoma (MCL) is one of the most aggressive lymphoid neoplasms whose pathogenesis is not fully understood. The neural transcription factor SOX11 is overexpressed in most MCL but is not detected in other mature B-cell lymphomas or normal lymphoid cells. The specific expression of SOX11 in MCL suggests that it may be an important element in the development of this tumor, but its potential function is not known. Here, we show that SOX11 promotes tumor growth in a MCL-xenotransplant mouse model. Using chromatin immunoprecipitation microarray analysis combined with gene expression profiling upon SOX11 knockdown, we identify target genes and transcriptional programs regulated by SOX11 including the block of mature B-cell differentiation, modulation of cell cycle, apoptosis, and stem cell development. PAX5 emerges as one of the major SOX11 direct targets. SOX11 silencing downregulates PAX5, induces BLIMP1 expression, and promotes the shift from a mature B cell into the initial plasmacytic differentiation phenotype in both primary tumor cells and an in vitro model. Our results suggest that SOX11 contributes to tumor development by altering the terminal B-cell differentiation program of MCL and provide perspectives that may have clinical implications in the diagnosis and design of new therapeutic strategies.


Assuntos
Linfócitos B/fisiologia , Diferenciação Celular/genética , Linfoma de Célula do Manto/genética , Fator de Transcrição PAX5/genética , Fatores de Transcrição SOXC/fisiologia , Animais , Linfócitos B/metabolismo , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Linfoma de Célula do Manto/patologia , Linfoma de Célula do Manto/fisiopatologia , Linfopoese/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Invasividade Neoplásica , Fator de Transcrição PAX5/metabolismo , Fatores de Transcrição SOXC/genética , Fatores de Transcrição SOXC/metabolismo , Transplante Heterólogo
14.
PLoS One ; 6(6): e21382, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21738649

RESUMO

Recent studies have shown aberrant expression of SOX11 in various types of aggressive B-cell neoplasms. To elucidate the molecular mechanisms leading to such deregulation, we performed a comprehensive SOX11 gene expression and epigenetic study in stem cells, normal hematopoietic cells and different lymphoid neoplasms. We observed that SOX11 expression is associated with unmethylated DNA and presence of activating histone marks (H3K9/14Ac and H3K4me3) in embryonic stem cells and some aggressive B-cell neoplasms. In contrast, adult stem cells, normal hematopoietic cells and other lymphoid neoplasms do not express SOX11. Such repression was associated with silencing histone marks H3K9me2 and H3K27me3. The SOX11 promoter of non-malignant cells was consistently unmethylated whereas lymphoid neoplasms with silenced SOX11 tended to acquire DNA hypermethylation. SOX11 silencing in cell lines was reversed by the histone deacetylase inhibitor SAHA but not by the DNA methyltransferase inhibitor AZA. These data indicate that, although DNA hypermethylation of SOX11 is frequent in lymphoid neoplasms, it seems to be functionally inert, as SOX11 is already silenced in the hematopoietic system. In contrast, the pathogenic role of SOX11 is associated with its de novo expression in some aggressive lymphoid malignancies, which is mediated by a shift from inactivating to activating histone modifications.


Assuntos
Epigênese Genética/genética , Histonas/metabolismo , Linfoma/genética , Linfoma/metabolismo , Fatores de Transcrição SOXC/genética , Western Blotting , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Metilação de DNA/efeitos dos fármacos , Metilação de DNA/genética , Metilação de DNA/fisiologia , Epigênese Genética/efeitos dos fármacos , Inibidores de Histona Desacetilases/farmacologia , Humanos , Técnicas In Vitro , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase Reversa
15.
Cancer Res ; 70(4): 1408-18, 2010 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-20124476

RESUMO

Mantle cell lymphoma (MCL) is typically a very aggressive disease with poor outcomes, but some cases display an indolent behavior that might not necessitate treatment at diagnosis. To define molecular criteria that might permit recognition of such cases, we compared the clinicopathologic features, gene expression, and genomic profile of patients who had indolent or conventional disease (iMCL or cMCL). Patients with iMCL displayed nonnodal leukemic disease with predominantly hypermutated IGVH and noncomplex karyotypes. iMCL and cMCL shared a common gene expression profile that differed from other leukemic lymphoid neoplasms. However, we identified a signature of 13 genes that was highly expressed in cMCL but underexpressed in iMCL. SOX11 was notable in this signature and we confirmed a restriction of SOX11 protein expression to cMCL. To validate the potential use of SOX11 as a biomarker for cMCL, we evaluated SOX11 protein expression in an independent series of 112 cases of MCL. Fifteen patients with SOX11-negative tumors exhibited more frequent nonnodal presentation and better survival compared with 97 patients with SOX11-positive MCL (5-year overall survival of 78% versus 36%, respectively; P = 0.001). In conclusion, we defined nonnodal presentation, predominantly hypermutated IGVH, lack of genomic complexity, and absence of SOX11 expression as qualities of a specific subtype of iMCL with excellent outcomes that might be managed more conservatively than cMCL.


Assuntos
Perfilação da Expressão Gênica , Linfoma de Célula do Manto/classificação , Linfoma de Célula do Manto/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise por Conglomerados , Progressão da Doença , Feminino , Seguimentos , Regulação Neoplásica da Expressão Gênica , Genômica/métodos , Humanos , Metástase Linfática , Linfoma de Célula do Manto/mortalidade , Linfoma de Célula do Manto/patologia , Masculino , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Fatores de Transcrição SOXC/análise , Fatores de Transcrição SOXC/genética , Análise de Sobrevida
16.
Blood ; 113(13): 3059-69, 2009 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-18984860

RESUMO

Mantle cell lymphoma (MCL) is genetically characterized by the t(11;14)(q13;q32) translocation and a high number of secondary chromosomal alterations. However, only a limited number of target genes have been identified. We have studied 10 MCL cell lines and 28 primary tumors with a combination of a high-density single-nucleotide polymorphism array and gene expression profiling. We detected highly altered genomes in the majority of the samples with a high number of partial uniparental disomies (UPDs). The UPD at 17p was one of the most common, and it was associated with TP53 gene inactivation. Homozygous deletions targeted 4 known tumor suppressor genes (CDKN2C, BCL2L11, CDKN2A, and RB1) and 6 new genes (FAF1, MAP2, SP100, MOBKL2B, ZNF280A, and PRAME). Gene amplification coupled with overexpression was identified in 35 different regions. The most recurrent amplified regions were 11q13.3-q13.5, 13q31.3, and 18q21.33, which targeted CCND1, C13orf25, and BCL2, respectively. Interestingly, the breakpoints flanking all the genomic alterations, including UPDs, were significantly associated with genomic regions enriched in copy number variants and segmental duplications, suggesting that the recombination at these regions may play a role in the genomic instability of MCL. This integrative genomic analysis has revealed target genes that may be potentially relevant in MCL pathogenesis.


Assuntos
Deleção Cromossômica , Amplificação de Genes , Genes Neoplásicos , Estudo de Associação Genômica Ampla/métodos , Linfoma de Célula do Manto/genética , Dissomia Uniparental/diagnóstico , Linhagem Celular Tumoral , Cromossomos Humanos Par 17 , Dosagem de Genes , Genes Neoplásicos/fisiologia , Homozigoto , Humanos , Perda de Heterozigosidade/genética , Linfoma de Célula do Manto/diagnóstico , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Polimorfismo de Nucleotídeo Único , Dissomia Uniparental/genética
17.
Genes Dev ; 22(18): 2496-506, 2008 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-18794347

RESUMO

The DNA polymerase delta processivity factor Proliferating Cell Nuclear Antigen (PCNA) promotes the DNA damage-induced degradation of the replication initiation factor Cdt1 via the CRL4(Cdt2) E3 ubiquitin ligase complex. Here we demonstrate that PCNA promotes the ubiquitylation and degradation of the CDK inhibitor p21 in cells irradiated with low dose of ultraviolet (UV) by a similar mechanism. Human cells that are depleted of Cul4, DDB1 (damage-specific DNA-binding protein-1), or the DCAF Cdt2, are deficient in the UV-induced ubiquitylation and degradation of p21. Depletion of mammalian cells of PCNA by siRNA, or mutations in p21 that abrogate PCNA binding, prevent UV-induced p21 ubiquitylation and degradation, indicating that physical binding with PCNA is necessary for the efficient ubiquitylation of p21 via the CRL4(Cdt2) ubiquitin ligase. Cdt2 functions as the substrate recruiting factor for p21 to the rest of the CRL4 ubiquitin ligase complex. The CRL4(Cdt2) E3 ubiquitin ligase ubiquitylates p21 both in vivo and in vitro, and its activity is dependent on the interaction of p21 with PCNA. Finally, we show that the CRL4(Cdt2) and the SCF(Skp2) ubiquitin ligases are redundant with each other in promoting the degradation of p21 during an unperturbed S phase of the cell cycle.


Assuntos
Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Antígeno Nuclear de Célula em Proliferação/fisiologia , Ubiquitina-Proteína Ligases/metabolismo , Sequência de Bases , Humanos , Hidrólise , Complexo de Endopeptidases do Proteassoma/metabolismo , Interferência de RNA , RNA Interferente Pequeno , Fase S , Proteínas Quinases Associadas a Fase S/metabolismo , Ubiquitinação , Raios Ultravioleta
18.
Mol Cell ; 27(3): 462-73, 2007 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-17679094

RESUMO

During the G1/S transition, p21 proteolysis is mediated by Skp2; however, p21 reaccumulates in G2 and is degraded again in prometaphase. How p21 degradation is controlled in mitosis remains unexplored. We found that Cdc20 (an activator of the ubiquitin ligase APC/C) binds p21 in cultured cells and identified a D box motif in p21 necessary for APC/C(Cdc20)-mediated ubiquitylation of p21. Overexpression of Cdc20 or Skp2 destabilized wild-type p21; however, only Skp2, but not Cdc20, was able to destabilize a p21(D box) mutant. Silencing of Cdc20 induced an accumulation of p21, increased the fraction of p21 bound to Cdk1, and inhibited Cdk1 activity in p21(+/+) prometaphase cells, but not in p21(-/-) cells. Thus, in prometaphase Cdc20 positively regulates Cdk1 by mediating the degradation of p21. We propose that the APC/C(Cdc20)-mediated degradation of p21 contributes to the full activation of Cdk1 necessary for mitotic events and prevents mitotic slippage during spindle checkpoint activation.


Assuntos
Proteínas de Ciclo Celular/fisiologia , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Prometáfase , Complexos Ubiquitina-Proteína Ligase/fisiologia , Ubiquitina-Proteína Ligases/antagonistas & inibidores , Ciclossomo-Complexo Promotor de Anáfase , Animais , Proteína Quinase CDC2/genética , Proteína Quinase CDC2/metabolismo , Proteínas Cdc20 , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Inibidor de Quinase Dependente de Ciclina p27/genética , Inibidor de Quinase Dependente de Ciclina p27/fisiologia , Inibidores Enzimáticos/farmacologia , Fibroblastos/metabolismo , Glioblastoma/metabolismo , Glioblastoma/patologia , Humanos , Immunoblotting , Imunoprecipitação , Pulmão , Camundongos , Camundongos Knockout , Mutagênese Sítio-Dirigida , Proteínas Quinases Associadas a Fase S/genética , Proteínas Quinases Associadas a Fase S/fisiologia , Ubiquitina/metabolismo
19.
Nature ; 428(6979): 190-3, 2004 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-15014502

RESUMO

Skp2 and its cofactor Cks1 are the substrate-targeting subunits of the SCF(Skp2-Cks1) (Skp1/Cul1/F-box protein) ubiquitin ligase complex that regulates entry into S phase by inducing the degradation of the cyclin-dependent kinase inhibitors p21 and p27 (ref. 1). Skp2 is an oncoprotein that often shows increased expression in human cancers; however, the mechanism that regulates its cellular abundance is not well understood. Here we show that both Skp2 and Cks1 proteins are unstable in G1 and that their degradation is mediated by the ubiquitin ligase APC/C(Cdh1) (anaphase-promoting complex/cyclosome and its activator Cdh1). Silencing of Cdh1 by RNA interference in G1 cells stabilizes Skp2 and Cks1, with a consequent increase in p21 and p27 proteolysis. Depletion of Cdh1 also increases the percentage of cells in S phase, whereas concomitant downregulation of Skp2 reverses this effect, showing that Skp2 is an essential target of APC/C(Cdh1). Expression of a stable Skp2 mutant that cannot bind APC/C(Cdh1) induces premature entry into S phase. Thus, the induction of Skp2 and Cks1 degradation in G1 represents a principal mechanism by which APC/C(Cdh1) prevents the unscheduled degradation of SCF(Skp2-Cks1) substrates and maintains the G1 state.


Assuntos
CDC2-CDC28 Quinases/metabolismo , Proteínas Quinases Associadas a Fase S/metabolismo , Proteínas Ligases SKP Culina F-Box/metabolismo , Complexos Ubiquitina-Proteína Ligase/metabolismo , Ciclossomo-Complexo Promotor de Anáfase , Animais , Proteínas de Transporte/metabolismo , Ciclo Celular , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/metabolismo , Divisão Celular , Linhagem Celular , Proteínas Culina/antagonistas & inibidores , Proteínas Culina/metabolismo , Ciclina A/metabolismo , Ciclina B/metabolismo , Quinases Ciclina-Dependentes , Humanos , Camundongos , Mutação , Proteínas Quinases/metabolismo , Processamento de Proteína Pós-Traducional , Interferência de RNA , Ratos , Proteínas Quinases Associadas a Fase S/genética , Proteínas Ligases SKP Culina F-Box/genética , Complexos Ubiquitina-Proteína Ligase/genética
20.
Cell ; 115(1): 71-82, 2003 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-14532004

RESUMO

We examined the mechanism responsible for the degradation of p21, a negative regulator of the cell division cycle. We found that p21 proteolysis requires functional ubiquitin and Nedd8 systems. Ubiquitinylated forms of p21 and p21(K0), a p21 mutant missing all lysines, are detected in vivo and in vitro, showing that the presence of lysines is dispensable for p21 ubiquitinylation. Instead, the free amino group of the N-terminal methionine of p21 is a site for ubiquitinylation in vivo. Although wild-type p21 is more abundantly ubiquitinylated than p21(K0) mutant due to the presence of internal lysine residues, their rates of proteolysis are indistinguishable. These results demonstrate that proteasomal degradation of p21 is regulated by the ubiquitin pathway and suggest that the site of the ubiquitin chain is critical in making p21 a competent substrate for the proteasome.


Assuntos
Ciclinas/metabolismo , Peptídeo Hidrolases/metabolismo , Complexo de Endopeptidases do Proteassoma , Ubiquitina/metabolismo , Animais , Ciclo Celular/fisiologia , Linhagem Celular , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/genética , Humanos , Lisina/metabolismo , Camundongos , Proteína NEDD8 , Ligação Proteica , Ubiquitina/genética , Ubiquitinas/metabolismo
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