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1.
Artigo em Alemão | MEDLINE | ID: mdl-38656540

RESUMO

Paraneoplastic pemphigus is a rare, life-threatening autoimmune disease that is clinically characterized by mostly extensive and refractory mucosal erosions and polymorphous skin lesions. We report here on a 16-year-old girl with isolated oral erosions, in whom mucosal pemphigoid was initially suspected and after treatment with prednisolone and dapsone marked improvement was achieved. However, a few months later the patient developed massive respiratory insufficiency as a result of bronchiolitis obliterans, so that a lung transplant was planned. As part of the preparatory diagnostic workup, unicentric, abdominally localized Castleman's disease was diagnosed, which ultimately led to the diagnosis of paraneoplastic pemphigus as evidenced by envoplakin autoantibodies. Tumor resection and subsequent lung transplantation achieved good results with sustained mucocutaneous remission.

2.
Clin Chem ; 67(4): 631-641, 2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33491069

RESUMO

BACKGROUND: Multiple technologies are available for detection of circulating tumor cells (CTCs), but standards to evaluate their technical performance are still lacking. This limits the applicability of CTC analysis in clinic routine. Therefore, in the context of the CANCER-ID consortium, we established a platform to assess technical validity of CTC detection methods in a European multi-center setting using non-small cell lung cancer (NSCLC) as a model. METHODS: We characterized multiple NSCLC cell lines to define cellular models distinct in their phenotype and molecular characteristics. Standardized tumor-cell-bearing blood samples were prepared at a central laboratory and sent to multiple European laboratories for processing according to standard operating procedures. The data were submitted via an online tool and centrally evaluated. Five CTC-enrichment technologies were tested. RESULTS: We could identify 2 cytokeratin expressing cell lines with distinct levels of EpCAM expression: NCI-H441 (EpCAMhigh, CKpos) and NCI-H1563 (EpCAMlow, CKpos). Both spiked tumor cell lines were detected by all technologies except for the CellSearch system that failed to enrich EpCAMlow NCI-H1563 cells. Mean recovery rates ranged between 49% and 75% for NCI-H411 and 32% and 76% for NCI-H1563 and significant differences were observed between the tested methods. CONCLUSIONS: This multi-national proficiency testing of CTC-enrichment technologies has importance in the establishment of guidelines for clinically applicable (pre)analytical workflows and the definition of minimal performance qualification requirements prior to clinical validation of technologies. It will remain in operation beyond the funding period of CANCER-ID in the context of the European Liquid Biopsy Society (ELBS).


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Células Neoplásicas Circulantes , Biomarcadores Tumorais , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Linhagem Celular Tumoral , Humanos , Neoplasias Pulmonares/diagnóstico
3.
Lancet Oncol ; 20(10): 1454-1466, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31405822

RESUMO

BACKGROUND: The clinical activity of fibroblast growth factor receptor (FGFR) inhibitors seems restricted to cancers harbouring rare FGFR genetic aberrations. In preclinical studies, high tumour FGFR mRNA expression predicted response to rogaratinib, an oral pan-FGFR inhibitor. We aimed to assess the safety, maximum tolerated dose, recommended phase 2 dose, pharmacokinetics, and preliminary clinical activity of rogaratinib. METHODS: We did a phase 1 dose-escalation and dose-expansion study of rogaratinib in adults with advanced cancers at 22 sites in Germany, Switzerland, South Korea, Singapore, Spain, and France. Eligible patients were aged 18 years or older, and were ineligible for standard therapy, with an Eastern Cooperative Oncology Group performance status of 0-2, a life expectancy of at least 3 months, and at least one measurable or evaluable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. During dose escalation, rogaratinib was administered orally twice daily at 50-800 mg in continuous 21-day cycles using a model-based dose-response analysis (continuous reassessment method). In the dose-expansion phase, all patients provided an archival formalin-fixed paraffin-embedded (FFPE) tumour biopsy or consented to a new biopsy at screening for the analysis of FGFR1-3 mRNA expression. In the dose-expansion phase, rogaratinib was given at the recommended dose for expansion to patients in four cohorts: urothelial carcinoma, head and neck squamous-cell cancer (HNSCC), non-small-cell lung cancer (NSCLC), and other solid tumour types. Primary endpoints were safety and tolerability, determination of maximum tolerated dose including dose-limiting toxicities and determination of recommended phase 2 dose, and pharmacokinetics of rogaratinib. Safety analyses were reported in all patients who received at least one dose of rogaratinib. Patients who completed cycle 1 or discontinued during cycle 1 due to an adverse event or dose-limiting toxicity were included in the evaluation of recommended phase 2 dose. Efficacy analyses were reported for all patients who received at least one dose of study drug and who had available post-baseline efficacy data. This ongoing study is registered with ClinicalTrials.gov, number NCT01976741, and is fully recruited. FINDINGS: Between Dec 30, 2013, and July 5, 2017, 866 patients were screened for FGFR mRNA expression, of whom 126 patients were treated (23 FGFR mRNA-unselected patients in the dose-escalation phase and 103 patients with FGFR mRNA-overexpressing tumours [52 patients with urothelial carcinoma, eight patients with HNSCC, 20 patients with NSCLC, and 23 patients with other tumour types] in the dose-expansion phase). No dose-limiting toxicities were reported and the maximum tolerated dose was not reached; 800 mg twice daily was established as the recommended phase 2 dose and was selected for the dose-expansion phase. The most common adverse events of any grade were hyperphosphataemia (in 77 [61%] of 126 patients), diarrhoea (in 65 [52%]), and decreased appetite (in 48 [38%]); and the most common grade 3-4 adverse events were fatigue (in 11 [9%] of 126 patients) and asymptomatic increased lipase (in 10 [8%]). Serious treatment-related adverse events were reported in five patients (decreased appetite and diarrhoea in one patient with urothelial carcinoma, and acute kidney injury [NSCLC], hypoglycaemia [other solid tumours], retinopathy [urothelial carcinoma], and vomiting [urothelial carcinoma] in one patient each); no treatment-related deaths occurred. Median follow-up after cessation of treatment was 32 days (IQR 25-36 days). In the expansion cohorts, 15 (15%; 95% CI 8·6-23·5) out of 100 evaluable patients achieved an objective response, with responses recorded in all four expansion cohorts (12 in the urothelial carcinoma cohort and one in each of the other three cohorts), and in ten (67%) of 15 FGFR mRNA-overexpressing tumours without apparent FGFR genetic aberration. INTERPRETATION: Rogaratinib was well tolerated and clinically active against several types of cancer. Selection by FGFR mRNA expression could be a useful additional biomarker to identify a broader patient population who could be eligible for FGFR inhibitor treatment. FUNDING: Bayer AG.


Assuntos
Antineoplásicos/administração & dosagem , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma de Células de Transição/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Piperazinas/administração & dosagem , Pirróis/administração & dosagem , Receptores de Fatores de Crescimento de Fibroblastos/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Tiofenos/administração & dosagem , Injúria Renal Aguda/induzido quimicamente , Idoso , Anorexia/induzido quimicamente , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacocinética , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma de Células de Transição/genética , Diarreia/induzido quimicamente , Fadiga/induzido quimicamente , Feminino , Humanos , Hiperfosfatemia/induzido quimicamente , Hipoglicemia/induzido quimicamente , Neoplasias Pulmonares/genética , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Piperazinas/efeitos adversos , Piperazinas/farmacocinética , Pirróis/efeitos adversos , Pirróis/farmacocinética , RNA Mensageiro/metabolismo , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/genética , Receptores de Fatores de Crescimento de Fibroblastos/antagonistas & inibidores , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Tiofenos/efeitos adversos , Tiofenos/farmacocinética , Vômito/induzido quimicamente
4.
Clin Chem ; 65(9): 1132-1140, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31235535

RESUMO

BACKGROUND: In human body fluids, microRNA (miRNA) can be found as circulating cell-free miRNA (cfmiRNA), as well as secreted into extracellular vesicles (EVmiRNA). miRNAs are being intensively evaluated as minimally invasive liquid biopsy biomarkers in patients with cancer. The growing interest in developing clinical assays for circulating miRNA necessitates careful consideration of confounding effects of preanalytical and analytical parameters. METHODS: By using reverse transcription quantitative real-time PCR and next-generation sequencing (NGS), we compared extraction efficiencies of 5 different protocols for cfmiRNA and 2 protocols for EVmiRNA isolation in a multicentric manner. The efficiency of the different extraction methods was evaluated by measuring exogenously spiked cel-miR-39 and 6 targeted miRNAs in plasma from 20 healthy individuals. RESULTS: There were significant differences between the tested methods. Although column-based extraction methods were highly effective for the isolation of endogenous miRNA, phenol extraction combined with column-based miRNA purification and ultracentrifugation resulted in lower quality and quantity of isolated miRNA. Among all extraction methods, the ubiquitously expressed miR-16 was represented with high abundance when compared with other targeted miRNAs. In addition, the use of miR-16 as an endogenous control for normalization of quantification cycle values resulted in a decreased variability of column-based cfmiRNA extraction methods. Cluster analysis of normalized NGS counts clearly indicated a method-dependent bias. CONCLUSIONS: The choice of plasma miRNA extraction methods affects the selection of potential miRNA marker candidates and mechanistic interpretation of results, which should be done with caution, particularly across studies using different protocols.


Assuntos
MicroRNA Circulante/sangue , MicroRNA Circulante/isolamento & purificação , Idoso , Animais , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/isolamento & purificação , Caenorhabditis elegans/química , Fracionamento Químico/métodos , Vesículas Extracelulares/química , Feminino , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos
5.
Int J Cancer ; 145(5): 1346-1357, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-30807645

RESUMO

Aberrant activation in fibroblast growth factor signaling has been implicated in the development of various cancers, including squamous cell lung cancer, squamous cell head and neck carcinoma, colorectal and bladder cancer. Thus, fibroblast growth factor receptors (FGFRs) present promising targets for novel cancer therapeutics. Here, we evaluated the activity of a novel pan-FGFR inhibitor, rogaratinib, in biochemical, cellular and in vivo efficacy studies in a variety of preclinical cancer models. In vitro kinase activity assays demonstrate that rogaratinib potently and selectively inhibits the activity of FGFRs 1, 2, 3 and 4. In line with this, rogaratinib reduced proliferation in FGFR-addicted cancer cell lines of various cancer types including lung, breast, colon and bladder cancer. FGFR and ERK phosphorylation interruption by rogaratinib treatment in several FGFR-amplified cell lines suggests that the anti-proliferative effects are mediated by FGFR/ERK pathway inhibition. Furthermore, rogaratinib exhibited strong in vivo efficacy in several cell line- and patient-derived xenograft models characterized by FGFR overexpression. The observed efficacy of rogaratinib strongly correlated with FGFR mRNA expression levels. These promising results warrant further development of rogaratinib and clinical trials are currently ongoing (ClinicalTrials.gov Identifiers: NCT01976741, NCT03410693, NCT03473756).


Assuntos
Neoplasias da Mama/tratamento farmacológico , Neoplasias/tratamento farmacológico , Piperazinas/farmacologia , Pirróis/farmacologia , Receptores de Fatores de Crescimento de Fibroblastos/antagonistas & inibidores , Tiofenos/farmacologia , Animais , Antineoplásicos/farmacologia , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Células Endoteliais da Veia Umbilical Humana , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias/metabolismo , Fosforilação/efeitos dos fármacos , Distribuição Aleatória , Ratos , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Comput Struct Biotechnol J ; 16: 190-195, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29977481

RESUMO

We discuss the current status of liquid biopsy and its advantages and challenges with a focus on pre-analytical sample handling, technologies and workflows. The potential of circulating tumor cells and circulating tumor DNA is pointed out and an overview of corresponding technologies is given.

8.
Nature ; 555(7696): 321-327, 2018 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-29489754

RESUMO

Pan-cancer analyses that examine commonalities and differences among various cancer types have emerged as a powerful way to obtain novel insights into cancer biology. Here we present a comprehensive analysis of genetic alterations in a pan-cancer cohort including 961 tumours from children, adolescents, and young adults, comprising 24 distinct molecular types of cancer. Using a standardized workflow, we identified marked differences in terms of mutation frequency and significantly mutated genes in comparison to previously analysed adult cancers. Genetic alterations in 149 putative cancer driver genes separate the tumours into two classes: small mutation and structural/copy-number variant (correlating with germline variants). Structural variants, hyperdiploidy, and chromothripsis are linked to TP53 mutation status and mutational signatures. Our data suggest that 7-8% of the children in this cohort carry an unambiguous predisposing germline variant and that nearly 50% of paediatric neoplasms harbour a potentially druggable event, which is highly relevant for the design of future clinical trials.


Assuntos
Genoma Humano/genética , Genômica , Mutação/genética , Neoplasias/classificação , Neoplasias/genética , Adolescente , Adulto , Criança , Cromotripsia , Estudos de Coortes , Variações do Número de Cópias de DNA/genética , Diploide , Predisposição Genética para Doença/genética , Mutação em Linhagem Germinativa/genética , Humanos , Terapia de Alvo Molecular , Taxa de Mutação , Neoplasias/tratamento farmacológico , Proteína Supressora de Tumor p53/genética , Adulto Jovem
9.
Cancer Res ; 76(18): 5523-37, 2016 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-27635046

RESUMO

The broad clinical spectrum of neuroblastoma ranges from spontaneous regression to rapid progression despite intensive multimodal therapy. This diversity is not fully explained by known genetic aberrations, suggesting the possibility of epigenetic involvement in pathogenesis. In pursuit of this hypothesis, we took an integrative approach to analyze the methylomes, transcriptomes, and copy number variations in 105 cases of neuroblastoma, complemented by primary tumor- and cell line-derived global histone modification analyses and epigenetic drug treatment in vitro We found that DNA methylation patterns identify divergent patient subgroups with respect to survival and clinicobiologic variables, including amplified MYCN Transcriptome integration and histone modification-based definition of enhancer elements revealed intragenic enhancer methylation as a mechanism for high-risk-associated transcriptional deregulation. Furthermore, in high-risk neuroblastomas, we obtained evidence for cooperation between PRC2 activity and DNA methylation in blocking tumor-suppressive differentiation programs. Notably, these programs could be re-activated by combination treatments, which targeted both PRC2 and DNA methylation. Overall, our results illuminate how epigenetic deregulation contributes to neuroblastoma pathogenesis, with novel implications for its diagnosis and therapy. Cancer Res; 76(18); 5523-37. ©2016 AACR.


Assuntos
Metilação de DNA/genética , Epigênese Genética/genética , Neuroblastoma/genética , Adolescente , Linhagem Celular Tumoral , Criança , Pré-Escolar , Imunoprecipitação da Cromatina , Análise por Conglomerados , Feminino , Estudo de Associação Genômica Ampla , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Recém-Nascido , Estimativa de Kaplan-Meier , Masculino , Proteína Proto-Oncogênica N-Myc/genética , Neuroblastoma/mortalidade , Neuroblastoma/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Transcrição Gênica , Transcriptoma , Adulto Jovem
10.
Oncotarget ; 7(38): 61860-61873, 2016 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-27556362

RESUMO

Ependymomas in children can arise throughout all compartments of the central nervous system (CNS). Highly malignant paediatric ependymoma subtypes are Group A tumours of the posterior fossa (PF-EPN-A) and RELA-fusion positive (ST-EPN-RELA) tumours in the supratentorial compartment. It was repeatedly reported in smaller series that accumulation of p53 is frequently observed in ependymomas and that immunohistochemical staining correlates with poor clinical outcome, while TP53 mutations are rare. Our TP53 mutation analysis of 130 primary ependymomas identified a mutation rate of only 3%. Immunohistochemical analysis of 398 ependymomas confirmed previous results correlating the accumulation of p53 with inferior outcome. Among the p53-positive ependymomas, the vast majority exhibited a RELA fusion leading to the hypothesis that p53 inactivation might be linked to RELA positivity.In order to assess the potential of p53 reactivation through MDM2 inhibition in ependymoma, we evaluated the effects of Actinomycin-D and Nutlin-3 treatment in two preclinical ependymoma models representing the high-risk subtypes PF-EPN-A and ST-EPN-RELA. The IC-50 of the agent as determined by metabolic activity assays was in the lower nano-molar range (0.2-0.7 nM). Transcriptome analyses of high-dose (100 nM), low-dose (5 nM) and non-treated cells revealed re-expression of p53 dependent genes including p53 upregulated modulator of apoptosis (PUMA) after low-dose treatment. At the protein level, we validated the Actinomycin-D induced upregulation of PUMA, and of p53 interaction partners MDM2 and p21. Proapoptotic effects of low-dose application of the agent were confirmed by flow cytometry. Thus, Actinomycin-D could constitute a promising therapeutic option for ST-EPN-RELA ependymoma patients, whose tumours frequently exhibit p53 inactivation.


Assuntos
Dactinomicina/uso terapêutico , Ependimoma/tratamento farmacológico , Fator de Transcrição RelA/genética , Proteína Supressora de Tumor p53/genética , Animais , Apoptose , Linhagem Celular Tumoral , Inibidor de Quinase Dependente de Ciclina p21/genética , Análise Mutacional de DNA , Ependimoma/metabolismo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Imidazóis/metabolismo , Imuno-Histoquímica , Meduloblastoma/metabolismo , Camundongos , Neurônios/metabolismo , Piperazinas/metabolismo , Inibidores da Síntese de Proteínas/uso terapêutico , Proteínas Proto-Oncogênicas c-mdm2/genética , Células-Tronco/metabolismo , Resultado do Tratamento
11.
Viruses ; 8(5)2016 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-27213425

RESUMO

Combining virus-induced cytotoxic and immunotherapeutic effects, oncolytic virotherapy represents a promising therapeutic approach for high-grade glioma (HGG). A clinical trial has recently provided evidence for the clinical safety of the oncolytic parvovirus H-1 (H-1PV) in adult glioblastoma relapse patients. The present study assesses the efficacy of H-1PV in eliminating HGG initiating cells. H-1PV was able to enter and to transduce all HGG neurosphere culture models (n = 6), including cultures derived from adult glioblastoma, pediatric glioblastoma, and diffuse intrinsic pontine glioma. Cytotoxic effects induced by the virus have been observed in all HGG neurospheres at half maximal inhibitory concentration (IC50) doses of input virus between 1 and 10 plaque forming units per cell. H-1PV infection at this dose range was able to prevent tumorigenicity of NCH421k glioblastoma multiforme (GBM) "stem-like" cells in NOD/SCID mice. Interestingly NCH421R, an isogenic subclone with equal capacity of xenograft formation, but resistant to H-1PV infection could be isolated from the parental NCH421k culture. To reveal changes in gene expression associated with H-1PV resistance we performed a comparative gene expression analysis in these subclones. Several dysregulated genes encoding receptor proteins, endocytosis factors or regulators innate antiviral responses were identified and represent intriguing candidates for to further study molecular mechanisms of H-1PV resistance.


Assuntos
Parvovirus H-1/crescimento & desenvolvimento , Neuroglia/fisiologia , Neuroglia/virologia , Vírus Oncolíticos/crescimento & desenvolvimento , Células-Tronco/fisiologia , Células-Tronco/virologia , Animais , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Glioma/terapia , Xenoenxertos , Humanos , Camundongos Endogâmicos NOD , Camundongos SCID , Modelos Teóricos , Terapia Viral Oncolítica/métodos
12.
Int J Cancer ; 138(12): 2905-14, 2016 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-26856307

RESUMO

Chromothripsis is a recently discovered form of genomic instability, characterized by tens to hundreds of clustered DNA rearrangements resulting from a single dramatic event. Telomere dysfunction has been suggested to play a role in the initiation of this phenomenon, which occurs in a large number of tumor entities. Here, we show that telomere attrition can indeed lead to catastrophic genomic events, and that telomere patterns differ between cells analyzed before and after such genomic catastrophes. Telomere length and telomere stabilization mechanisms diverge between samples with and without chromothripsis in a given tumor subtype. Longitudinal analyses of the evolution of chromothriptic patterns identify either stable patterns between matched primary and relapsed tumors, or loss of the chromothriptic clone in the relapsed specimen. The absence of additional chromothriptic events occurring between the initial tumor and the relapsed tumor sample points to telomere stabilization after the initial chromothriptic event which prevents further shattering of the genome.


Assuntos
Neoplasias Cerebelares/genética , Instabilidade Genômica , Meduloblastoma/genética , Homeostase do Telômero , Estudos de Casos e Controles , Neoplasias Cerebelares/enzimologia , Transtornos Cromossômicos/enzimologia , Transtornos Cromossômicos/genética , Ependimoma/enzimologia , Ependimoma/genética , Expressão Gênica , Humanos , Meduloblastoma/enzimologia , Telomerase/genética , Telomerase/metabolismo
13.
Nucleic Acids Res ; 43(22): 10952-62, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26424849

RESUMO

Dnmt2 enzymes are cytosine-5 methyltransferases that methylate C38 of several tRNAs. We report here that the activities of two Dnmt2 homologs, Pmt1 from Schizosaccharomyces pombe and DnmA from Dictyostelium discoideum, are strongly stimulated by prior queuosine (Q) modification of the substrate tRNA. In vivo tRNA methylation levels were stimulated by growth of cells in queuine-containing medium; in vitro Pmt1 activity was enhanced on Q-containing RNA; and queuine-stimulated in vivo methylation was abrogated by the absence of the enzyme that inserts queuine into tRNA, eukaryotic tRNA-guanine transglycosylase. Global analysis of tRNA methylation in S. pombe showed a striking selectivity of Pmt1 for tRNA(Asp) methylation, which distinguishes Pmt1 from other Dnmt2 homologs. The present analysis also revealed a novel Pmt1- and Q-independent tRNA methylation site in S. pombe, C34 of tRNA(Pro). Notably, queuine is a micronutrient that is scavenged by higher eukaryotes from the diet and gut microflora. This work therefore reveals an unanticipated route by which the environment can modulate tRNA modification in an organism.


Assuntos
DNA (Citosina-5-)-Metiltransferases/metabolismo , Guanina/análogos & derivados , Micronutrientes/metabolismo , RNA de Transferência/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Dictyostelium/enzimologia , Guanina/metabolismo , Metilação , Pentosiltransferases/metabolismo , RNA de Transferência de Ácido Aspártico/metabolismo , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo
14.
EMBO J ; 34(18): 2350-62, 2015 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-26271101

RESUMO

The Dnmt2 enzyme utilizes the catalytic mechanism of eukaryotic DNA methyltransferases to methylate several tRNAs at cytosine 38. Dnmt2 mutant mice, flies, and plants were reported to be viable and fertile, and the biological function of Dnmt2 has remained elusive. Here, we show that endochondral ossification is delayed in newborn Dnmt2-deficient mice, which is accompanied by a reduction of the haematopoietic stem and progenitor cell population and a cell-autonomous defect in their differentiation. RNA bisulfite sequencing revealed that Dnmt2 methylates C38 of tRNA Asp(GTC), Gly(GCC), and Val(AAC), thus preventing tRNA fragmentation. Proteomic analyses from primary bone marrow cells uncovered systematic differences in protein expression that are due to specific codon mistranslation by tRNAs lacking Dnmt2-dependent methylation. Our observations demonstrate that Dnmt2 plays an important role in haematopoiesis and define a novel function of C38 tRNA methylation in the discrimination of near-cognate codons, thereby ensuring accurate polypeptide synthesis.


Assuntos
Diferenciação Celular/fisiologia , DNA (Citosina-5-)-Metiltransferases/metabolismo , Hematopoese/fisiologia , Células-Tronco Hematopoéticas/enzimologia , Biossíntese de Proteínas/fisiologia , Animais , Animais Recém-Nascidos , DNA (Citosina-5-)-Metiltransferases/genética , Células-Tronco Hematopoéticas/citologia , Metilação , Camundongos , Camundongos Knockout , Osteogênese/fisiologia , RNA de Transferência/genética , RNA de Transferência/metabolismo
15.
Acta Neuropathol ; 129(5): 669-78, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25752754

RESUMO

Pediatric glioblastoma (pedGBM) is amongst the most common malignant brain tumors of childhood and carries a dismal prognosis. In contrast to adult GBM, few molecular prognostic markers for the pediatric counterpart have been established. We, therefore, investigated the prognostic significance of genomic and epigenetic alterations through molecular analysis of 202 pedGBM (1-18 years) with comprehensive clinical annotation. Routinely prepared formalin-fixed paraffin-embedded tumor samples were assessed for genome-wide DNA methylation profiles, with known candidate genes screened for alterations via direct sequencing or FISH. Unexpectedly, a subset of histologically diagnosed GBM (n = 40, 20 %) displayed methylation profiles similar to those of either low-grade gliomas or pleomorphic xanthoastrocytomas (PXA). These tumors showed a markedly better prognosis, with molecularly PXA-like tumors frequently harboring BRAF V600E mutations and 9p21 (CDKN2A) homozygous deletion. The remaining 162 tumors with pedGBM molecular signatures comprised four subgroups: H3.3 G34-mutant (15 %), H3.3/H3.1 K27-mutant (43 %), IDH1-mutant (6 %), and H3/IDH wild-type (wt) GBM (36 %). These subgroups were associated with specific cytogenetic aberrations, MGMT methylation patterns and clinical outcomes. Analysis of follow-up data identified a set of biomarkers feasible for use in risk stratification: pedGBM with any oncogene amplification and/or K27M mutation (n = 124) represents a particularly unfavorable group, with 3-year overall survival (OS) of 5 %, whereas tumors without these markers (n = 38) define a more favorable group (3-year OS ~70 %).Combined with the lower grade-like lesions, almost 40 % of pedGBM cases had distinct molecular features associated with a more favorable outcome. This refined prognostication method for pedGBM using a molecular risk algorithm may allow for improved therapeutic choices and better planning of clinical trial stratification for this otherwise devastating disease.


Assuntos
Biomarcadores Tumorais/genética , Genes p16 , Glioblastoma/genética , Proteínas Proto-Oncogênicas B-raf/genética , Adolescente , Astrocitoma/genética , Neoplasias Encefálicas/genética , Transformação Celular Neoplásica/genética , Criança , Pré-Escolar , Metilação de DNA , Epigenômica , Feminino , Genômica , Glioblastoma/patologia , Glioblastoma/fisiopatologia , Humanos , Hibridização in Situ Fluorescente , Lactente , Masculino , Mutação , Gradação de Tumores/métodos , Prognóstico , Análise de Sequência de DNA
16.
Cancer Res ; 75(10): 2120-30, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-25808873

RESUMO

Chronic inflammation represents a major risk factor for tumor formation, but the underlying mechanisms have remained largely unknown. Epigenetic mechanisms can record the effects of environmental challenges on the genome level and could therefore play an important role in the pathogenesis of inflammation-associated tumors. Using single-base methylation maps and transcriptome analyses of a colitis-induced mouse colon cancer model, we identified a novel epigenetic program that is characterized by hypermethylation of DNA methylation valleys that are characterized by low CpG density and active chromatin marks. This program is conserved and functional in mouse intestinal adenomas and results in silencing of active intestinal genes that are involved in gastrointestinal homeostasis and injury response. Further analyses reveal that the program represents a prominent feature of human colorectal cancer and can be used to correctly classify colorectal cancer samples with high accuracy. Together, our results show that inflammatory signals establish a novel epigenetic program that silences a specific set of genes that contribute to inflammation-induced cellular transformation.


Assuntos
Adenocarcinoma/genética , Adenoma/genética , Colite/genética , Neoplasias Colorretais/genética , Adenocarcinoma/imunologia , Adenocarcinoma/metabolismo , Adenoma/imunologia , Adenoma/metabolismo , Animais , Colite/metabolismo , Neoplasias Colorretais/imunologia , Neoplasias Colorretais/metabolismo , Metilação de DNA , Epigênese Genética , Feminino , Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos Endogâmicos C57BL
17.
Hum Mol Genet ; 23(25): 6826-37, 2014 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-25104850

RESUMO

Uncontrolled cell cycle entry, resulting from deregulated CDK-RB1-E2F pathway activity, is a crucial determinant of neuroblastoma cell malignancy. Here we identify neuroblastoma-suppressive functions of the p19-INK4d CDK inhibitor and uncover mechanisms of its repression in high-risk neuroblastomas. Reduced p19-INK4d expression was associated with poor event-free and overall survival and neuroblastoma risk factors including amplified MYCN in a set of 478 primary neuroblastomas. High MYCN expression repressed p19-INK4d mRNA and protein levels in different neuroblastoma cell models with conditional MYCN expression. MassARRAY and 450K methylation analyses of 105 primary neuroblastomas uncovered a differentially methylated region within p19-INK4d. Hypermethylation of this region was associated with reduced p19-INK4d expression. In accordance, p19-INK4d expression was activated upon treatment with the demethylating agent, 2'-deoxy-5-azacytidine, in neuroblastoma cell lines. Ectopic p19-INK4d expression decreased viability, clonogenicity and the capacity for anchorage-independent growth of neuroblastoma cells, and shifted the cell cycle towards the G1/0 phase. p19-INK4d also induced neurite-like processes and markers of neuronal differentiation. Moreover, neuroblastoma cell differentiation, induced by all-trans retinoic acid or NGF-NTRK1-signaling, activated p19-INK4d expression. Our findings pinpoint p19-INK4d as a neuroblastoma suppressor and provide evidence for MYCN-mediated repression and for epigenetic silencing of p19-INK4d by DNA hypermethylation in high-risk neuroblastomas.


Assuntos
Inibidor de Quinase Dependente de Ciclina p19/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias do Sistema Nervoso/genética , Neuroblastoma/genética , Neurônios/metabolismo , Proteínas Nucleares/genética , Proteínas Oncogênicas/genética , Adolescente , Adulto , Antimetabólitos Antineoplásicos/farmacologia , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Criança , Pré-Escolar , Inibidor de Quinase Dependente de Ciclina p19/metabolismo , Metilação de DNA/efeitos dos fármacos , Decitabina , Epigênese Genética , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Proteína Proto-Oncogênica N-Myc , Estadiamento de Neoplasias , Neoplasias do Sistema Nervoso/metabolismo , Neoplasias do Sistema Nervoso/mortalidade , Neoplasias do Sistema Nervoso/patologia , Neuroblastoma/metabolismo , Neuroblastoma/mortalidade , Neuroblastoma/patologia , Neurônios/efeitos dos fármacos , Neurônios/patologia , Proteínas Nucleares/metabolismo , Proteínas Oncogênicas/metabolismo , Transdução de Sinais , Análise de Sobrevida , Tretinoína/farmacologia
18.
Cancer Cell ; 25(3): 393-405, 2014 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-24651015

RESUMO

Smoothened (SMO) inhibitors recently entered clinical trials for sonic-hedgehog-driven medulloblastoma (SHH-MB). Clinical response is highly variable. To understand the mechanism(s) of primary resistance and identify pathways cooperating with aberrant SHH signaling, we sequenced and profiled a large cohort of SHH-MBs (n = 133). SHH pathway mutations involved PTCH1 (across all age groups), SUFU (infants, including germline), and SMO (adults). Children >3 years old harbored an excess of downstream MYCN and GLI2 amplifications and frequent TP53 mutations, often in the germline, all of which were rare in infants and adults. Functional assays in different SHH-MB xenograft models demonstrated that SHH-MBs harboring a PTCH1 mutation were responsive to SMO inhibition, whereas tumors harboring an SUFU mutation or MYCN amplification were primarily resistant.


Assuntos
Resistencia a Medicamentos Antineoplásicos/genética , Proteínas Hedgehog/genética , Meduloblastoma/genética , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Receptores Acoplados a Proteínas G/genética , Adolescente , Adulto , Animais , Sequência de Bases , Compostos de Bifenilo/uso terapêutico , Neoplasias Cerebelares/tratamento farmacológico , Neoplasias Cerebelares/genética , Criança , Pré-Escolar , RNA Helicases DEAD-box/genética , Variações do Número de Cópias de DNA/genética , Feminino , Perfilação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Fatores de Transcrição Kruppel-Like/genética , Masculino , Meduloblastoma/tratamento farmacológico , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Dados de Sequência Molecular , Proteína Proto-Oncogênica N-Myc , Transplante de Neoplasias , Proteínas Nucleares/genética , Proteínas Oncogênicas/genética , Receptores Patched , Receptor Patched-1 , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Regiões Promotoras Genéticas/genética , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Piridinas/uso terapêutico , Receptores de Superfície Celular/genética , Proteínas Repressoras/genética , Transdução de Sinais/genética , Receptor Smoothened , Telomerase/genética , Proteína Supressora de Tumor p53/genética , Adulto Jovem , Proteína Gli2 com Dedos de Zinco
19.
Horm Res Paediatr ; 81(3): 196-203, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24481334

RESUMO

BACKGROUND: GNAS encodes the α subunit of the stimulatory G protein (Gsα). Maternal inherited Gsα mutations cause pseudohypoparathyroidism type Ia (PHP-Ia), associated with shortening of the 4th and 5th metacarpals. AIMS: Here we investigated the Gsα pathway in short patients with distinct shortening of the 4th and 5th metacarpals. METHODS: In 571 children with short stature and 4 patients with PHP-Ia metacarpal bone lengths were measured. In identified patients we analysed the Gsα protein function in platelets, performed GNAS sequencing, and epigenetic analysis of four significant differentially methylated regions. RESULTS: In 51 patients (8.9%) shortening of the 4th and 5th metacarpals was more pronounced than their height deficit. No GNAS coding mutations were identified in 20 analysed patients, except in 2 PHP-Ia patients. Gsα activity was reduced in all PHP-Ia patients and in 25% of the analysed patients. No significant methylation changes were identified. CONCLUSIONS: Our findings suggest that patients with short stature and distinct metacarpal bone shortening could be part of the wide variety of PHP/PPHP, therefore it was worthwhile analysing the Gsα protein function and GNAS gene in these patients in order to further elucidate the phenotype and genotype of Gsα dysfunction.


Assuntos
Loci Gênicos , Transtornos do Crescimento , Ossos Metacarpais , Pseudo-Hipoparatireoidismo , Adolescente , Criança , Pré-Escolar , Feminino , Transtornos do Crescimento/diagnóstico por imagem , Transtornos do Crescimento/genética , Transtornos do Crescimento/metabolismo , Humanos , Lactente , Masculino , Ossos Metacarpais/diagnóstico por imagem , Ossos Metacarpais/metabolismo , Tamanho do Órgão/genética , Pseudo-Hipoparatireoidismo/diagnóstico por imagem , Pseudo-Hipoparatireoidismo/genética , Pseudo-Hipoparatireoidismo/metabolismo , Radiografia
20.
Nat Rev Cancer ; 14(2): 92-107, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24457416

RESUMO

We have extended our understanding of the molecular biology that underlies adult glioblastoma over many years. By contrast, high-grade gliomas in children and adolescents have remained a relatively under-investigated disease. The latest large-scale genomic and epigenomic profiling studies have yielded an unprecedented abundance of novel data and provided deeper insights into gliomagenesis across all age groups, which has highlighted key distinctions but also some commonalities. As we are on the verge of dissecting glioblastomas into meaningful biological subgroups, this Review summarizes the hallmark genetic alterations that are associated with distinct epigenetic features and patient characteristics in both paediatric and adult disease, and examines the complex interplay between the glioblastoma genome and epigenome.


Assuntos
Epigenômica , Glioblastoma/genética , Neoplasias de Tecido Nervoso/genética , Fatores Etários , Humanos
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