Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 15.475
Filtrar
1.
Cochrane Database Syst Rev ; 7: CD012022, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32735048

RESUMO

BACKGROUND: Chronic lymphocytic leukaemia (CLL) is the most common cancer of the lymphatic system in Western countries. Several clinical and biological factors for CLL have been identified. However, it remains unclear which of the available prognostic models combining those factors can be used in clinical practice to predict long-term outcome in people newly-diagnosed with CLL. OBJECTIVES: To identify, describe and appraise all prognostic models developed to predict overall survival (OS), progression-free survival (PFS) or treatment-free survival (TFS) in newly-diagnosed (previously untreated) adults with CLL, and meta-analyse their predictive performances. SEARCH METHODS: We searched MEDLINE (from January 1950 to June 2019 via Ovid), Embase (from 1974 to June 2019) and registries of ongoing trials (to 5 March 2020) for development and validation studies of prognostic models for untreated adults with CLL. In addition, we screened the reference lists and citation indices of included studies. SELECTION CRITERIA: We included all prognostic models developed for CLL which predict OS, PFS, or TFS, provided they combined prognostic factors known before treatment initiation, and any studies that tested the performance of these models in individuals other than the ones included in model development (i.e. 'external model validation studies'). We included studies of adults with confirmed B-cell CLL who had not received treatment prior to the start of the study. We did not restrict the search based on study design. DATA COLLECTION AND ANALYSIS: We developed a data extraction form to collect information based on the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS). Independent pairs of review authors screened references, extracted data and assessed risk of bias according to the Prediction model Risk Of Bias ASsessment Tool (PROBAST). For models that were externally validated at least three times, we aimed to perform a quantitative meta-analysis of their predictive performance, notably their calibration (proportion of people predicted to experience the outcome who do so) and discrimination (ability to differentiate between people with and without the event) using a random-effects model. When a model categorised individuals into risk categories, we pooled outcome frequencies per risk group (low, intermediate, high and very high). We did not apply GRADE as guidance is not yet available for reviews of prognostic models. MAIN RESULTS: From 52 eligible studies, we identified 12 externally validated models: six were developed for OS, one for PFS and five for TFS. In general, reporting of the studies was poor, especially predictive performance measures for calibration and discrimination; but also basic information, such as eligibility criteria and the recruitment period of participants was often missing. We rated almost all studies at high or unclear risk of bias according to PROBAST. Overall, the applicability of the models and their validation studies was low or unclear; the most common reasons were inappropriate handling of missing data and serious reporting deficiencies concerning eligibility criteria, recruitment period, observation time and prediction performance measures. We report the results for three models predicting OS, which had available data from more than three external validation studies: CLL International Prognostic Index (CLL-IPI) This score includes five prognostic factors: age, clinical stage, IgHV mutational status, B2-microglobulin and TP53 status. Calibration: for the low-, intermediate- and high-risk groups, the pooled five-year survival per risk group from validation studies corresponded to the frequencies observed in the model development study. In the very high-risk group, predicted survival from CLL-IPI was lower than observed from external validation studies. Discrimination: the pooled c-statistic of seven external validation studies (3307 participants, 917 events) was 0.72 (95% confidence interval (CI) 0.67 to 0.77). The 95% prediction interval (PI) of this model for the c-statistic, which describes the expected interval for the model's discriminative ability in a new external validation study, ranged from 0.59 to 0.83. Barcelona-Brno score Aimed at simplifying the CLL-IPI, this score includes three prognostic factors: IgHV mutational status, del(17p) and del(11q). Calibration: for the low- and intermediate-risk group, the pooled survival per risk group corresponded to the frequencies observed in the model development study, although the score seems to overestimate survival for the high-risk group. Discrimination: the pooled c-statistic of four external validation studies (1755 participants, 416 events) was 0.64 (95% CI 0.60 to 0.67); 95% PI 0.59 to 0.68. MDACC 2007 index score The authors presented two versions of this model including six prognostic factors to predict OS: age, B2-microglobulin, absolute lymphocyte count, gender, clinical stage and number of nodal groups. Only one validation study was available for the more comprehensive version of the model, a formula with a nomogram, while seven studies (5127 participants, 994 events) validated the simplified version of the model, the index score. Calibration: for the low- and intermediate-risk groups, the pooled survival per risk group corresponded to the frequencies observed in the model development study, although the score seems to overestimate survival for the high-risk group. Discrimination: the pooled c-statistic of the seven external validation studies for the index score was 0.65 (95% CI 0.60 to 0.70); 95% PI 0.51 to 0.77. AUTHORS' CONCLUSIONS: Despite the large number of published studies of prognostic models for OS, PFS or TFS for newly-diagnosed, untreated adults with CLL, only a minority of these (N = 12) have been externally validated for their respective primary outcome. Three models have undergone sufficient external validation to enable meta-analysis of the model's ability to predict survival outcomes. Lack of reporting prevented us from summarising calibration as recommended. Of the three models, the CLL-IPI shows the best discrimination, despite overestimation. However, performance of the models may change for individuals with CLL who receive improved treatment options, as the models included in this review were tested mostly on retrospective cohorts receiving a traditional treatment regimen. In conclusion, this review shows a clear need to improve the conducting and reporting of both prognostic model development and external validation studies. For prognostic models to be used as tools in clinical practice, the development of the models (and their subsequent validation studies) should adapt to include the latest therapy options to accurately predict performance. Adaptations should be timely.


Assuntos
Leucemia Linfocítica Crônica de Células B/mortalidade , Modelos Teóricos , Adulto , Fatores Etários , Viés , Biomarcadores Tumorais , Calibragem , Intervalos de Confiança , Análise Discriminante , Intervalo Livre de Doença , Feminino , Genes p53/genética , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/patologia , Masculino , Estadiamento de Neoplasias , Prognóstico , Intervalo Livre de Progressão , Receptores de Antígenos de Linfócitos B/genética , Reprodutibilidade dos Testes , Proteína Supressora de Tumor p53/genética
2.
Ann Hematol ; 99(10): 2343-2349, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32833105

RESUMO

Ibrutinib-based therapy represents a recent success in managing high-risk CLL patients with 17p/TP53 deletion. However, a subset of CLL patients are resistant to therapy. Deletion of lipoprotein lipase (LPL) has been postulated as a potential evasion mechanism to ibrutinib-based therapy. In this study, we assessed for LPL deletion by fluorescence in situ hybridization in 176 consecutive CLL patients with 17p/TP53 deletion. LPL deletion was detected in 35 (20%) of CLL patients. Patients with LPL deletion (del) showed a higher frequency of CD38 expression but have comparable frequencies of somatic hypermutation and ZAP-70 expression compared with patients with normal (nml) LPL. Gene mutation analysis showed that TP53 was mutated in 68% of LPL-del versus 91% of LPL-nml patients. The overall response to ibrutinib-based therapy was 57%, including 37% complete remission (CR) and 20% partial remission (PR) in patients with LPL-del versus 90% (56% CR and 34% PR) in patients with LPL-nml (p < 0.001). LPL-del patients also showed a poorer overall survival (OS) compared with patients with LPL-nml (median OS, 236 months versus undefined, p < 0.001). In summary, the data presented establish an association between LPL deletion, resistance to ibrutinib-based therapy, and poorer overall survival in TP53-deleted CLL patients. We suggest that LPL deletion might be utilized as a biomarker for risk stratification and to predict therapeutic response in this high-risk group of CLL patients.


Assuntos
Antineoplásicos/uso terapêutico , Resistencia a Medicamentos Antineoplásicos/genética , Deleção de Genes , Leucemia Linfocítica Crônica de Células B/genética , Lipase Lipoproteica/deficiência , Inibidores de Proteínas Quinases/uso terapêutico , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais , Compostos Bicíclicos Heterocíclicos com Pontes/administração & dosagem , Feminino , Genes p53 , Humanos , Hibridização in Situ Fluorescente , Estimativa de Kaplan-Meier , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/mortalidade , Lipase Lipoproteica/genética , Lipase Lipoproteica/fisiologia , Masculino , Pessoa de Meia-Idade , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Modelos de Riscos Proporcionais , Pirazóis/administração & dosagem , Pirimidinas/administração & dosagem , Medição de Risco , Rituximab/administração & dosagem , Sulfonamidas/administração & dosagem , Resultado do Tratamento , Proteína Supressora de Tumor p53/deficiência , Proteína-Tirosina Quinase ZAP-70/biossíntese , Proteína-Tirosina Quinase ZAP-70/genética
3.
Cancer Sci ; 111(7): 2336-2348, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32437590

RESUMO

Dietary fat consumption during accelerated stages of mammary gland development, such as peripubertal maturation or pregnancy, is known to increase the risk for breast cancer. However, the underlying molecular mechanisms are not fully understood. Here we examined the gene expression profile of mouse mammary epithelial cells (MMECs) on exposure to a high-fat diet (HFD) or control diet (CD). Trp53-/- female mice were fed with the experimental diets for 5 weeks during the peripubertal period (3-8 weeks of age). The treatment showed no significant difference in body weight between the HFD-fed mice and CD-fed mice. However, gene set enrichment analysis predicted a significant enrichment of c-Myc target genes in animals fed HFD. Furthermore, we detected enhanced activity and stabilization of c-Myc protein in MMECs exposed to a HFD. This was accompanied by augmented c-Myc phosphorylation at S62 with a concomitant increase in ERK phosphorylation. Moreover, MMECs derived from HFD-fed Trp53-/- mouse showed increased colony- and sphere-forming potential that was dependent on c-Myc. Further, oleic acid, a major fatty acid constituent of the HFD, and TAK-875, an agonist to G protein-coupled receptor 40 (a receptor for oleic acid), enhanced c-Myc stabilization and MMEC proliferation. Overall, our data indicate that HFD influences MMECs by stabilizing an oncoprotein, pointing to a novel mechanism underlying dietary fat-mediated mammary carcinogenesis.


Assuntos
Dieta Hiperlipídica , Epitélio/metabolismo , Glândulas Mamárias Animais/metabolismo , Glândulas Mamárias Animais/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Maturidade Sexual , Animais , Linhagem Celular Tumoral , Feminino , Genes p53 , Humanos , Camundongos , Camundongos Knockout , Obesidade/etiologia , Obesidade/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Puberdade , Células Tumorais Cultivadas
4.
Proc Natl Acad Sci U S A ; 117(20): 11136-11146, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32371487

RESUMO

The intestinal epithelium acts as a barrier between the organism and its microenvironment, including the gut microbiota. It is the most rapidly regenerating tissue in the human body thanks to a pool of intestinal stem cells (ISCs) expressing Lgr5 The intestinal epithelium has to cope with continuous stress linked to its digestive and barrier functions. Epithelial repair is crucial to maintain its integrity, and Lgr5-positive intestinal stem cell (Lgr5+ISC) resilience following cytotoxic stresses is central to this repair stage. We show here that autophagy, a pathway allowing the lysosomal degradation of intracellular components, plays a crucial role in the maintenance and genetic integrity of Lgr5+ISC under physiological and stress conditions. Using conditional mice models lacking the autophagy gene Atg7 specifically in all intestinal epithelial cells or in Lgr5+ISC, we show that loss of Atg7 induces the p53-mediated apoptosis of Lgr5+ISC. Mechanistically, this is due to increasing oxidative stress, alterations to interactions with the microbiota, and defective DNA repair. Following irradiation, we show that Lgr5+ISC repair DNA damage more efficiently than their progenitors and that this protection is Atg7 dependent. Accordingly, we found that the stimulation of autophagy on fasting protects Lgr5+ISC against DNA damage and cell death mediated by oxaliplatin and doxorubicin treatments. Finally, p53 deletion prevents the death of Atg7-deficient Lgr5+ISC but promotes genetic instability and tumor formation. Altogether, our findings provide insights into the mechanisms underlying maintenance and integrity of ISC and highlight the key functions of Atg7 and p53.


Assuntos
Proteína 7 Relacionada à Autofagia/metabolismo , Autofagia/fisiologia , Intestinos/fisiologia , Células-Tronco/metabolismo , Animais , Apoptose , Proteína 7 Relacionada à Autofagia/genética , Dano ao DNA , Reparo do DNA , Modelos Animais de Doenças , Células Epiteliais/metabolismo , Feminino , Genes p53/genética , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Intestinos/patologia , Masculino , Camundongos , Camundongos Knockout , Receptores Acoplados a Proteínas-G/metabolismo , Células-Tronco/citologia
5.
Nature ; 582(7810): 100-103, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32461694

RESUMO

Cancers develop as a result of driver mutations1,2 that lead to clonal outgrowth and the evolution of disease3,4. The discovery and functional characterization of individual driver mutations are central aims of cancer research, and have elucidated myriad phenotypes5 and therapeutic vulnerabilities6. However, the serial genetic evolution of mutant cancer genes7,8 and the allelic context in which they arise is poorly understood in both common and rare cancer genes and tumour types. Here we find that nearly one in four human tumours contains a composite mutation of a cancer-associated gene, defined as two or more nonsynonymous somatic mutations in the same gene and tumour. Composite mutations are enriched in specific genes, have an elevated rate of use of less-common hotspot mutations acquired in a chronology driven in part by oncogenic fitness, and arise in an allelic configuration that reflects context-specific selective pressures. cis-acting composite mutations are hypermorphic in some genes in which dosage effects predominate (such as TERT), whereas they lead to selection of function in other genes (such as TP53). Collectively, composite mutations are driver alterations that arise from context- and allele-specific selective pressures that are dependent in part on gene and mutation function, and which lead to complex-often neomorphic-functions of biological and therapeutic importance.


Assuntos
Carcinogênese/genética , Modelos Genéticos , Mutação , Neoplasias/genética , Oncogenes/genética , Alelos , Animais , Feminino , Genes p53/genética , Humanos , Camundongos , Seleção Genética , Telomerase/genética
6.
Pol J Pathol ; 71(1): 7-12, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32429649

RESUMO

Phyllodes tumor of the breast (PTB) is a rare neoplasm and accounts for 0.2-2.0% of breast cancer in women. Histopathological diagnosis of the tumor is difficult, and histological features do not always predict the course of the disease and the risk of progression. Pathogenesis and molecular biological characteristics as well as PTB prognostic factors are unknown. In search for genetic factors affecting PTB progression, 10 patients were analyzed for whom material from the primary tumor and local recurrence was available. DNA isolated from paraffin blocks was sequenced using the next-generation sequencing method (NGS). In 4 pairs, consisting of primary tumor and local recurrence, probably pathogenic/pathogenic variants were detected, and in three pairs they were observed in the CDKN2A gene, while other variants were found in PTEN and TP53 genes. NGS results indicate that the above-mentioned variants are hereditary, which suggests that the CDKN2A gene might be involved in cancerogenesis of PTB. Additionally, the selected pathogenic variant of EGFR gene was exclusively detected in one recuurent tumor, which might suggest the involvement of this gene in the mechanism of progression. In order to determine if this variant is associated with progression, the frequency of this mutation should be examined in larger group of malignant and borderline tumors.


Assuntos
Neoplasias da Mama/genética , Mutação , Tumor Filoide/genética , Feminino , Genes erbB-1 , Genes p16 , Genes p53 , Humanos , Recidiva Local de Neoplasia , PTEN Fosfo-Hidrolase
7.
Gene ; 748: 144699, 2020 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-32334023

RESUMO

Pigs have been increasingly recognized as a relevant model for studying many human diseases. However, functions and regulations of numerous critical molecules involved in human diseases are not well characterized in pigs, including the prominent tumor suppressor p53, a transcription factor involved in various anti-proliferative processes. In this study, we systematically characterized porcine p53 (p-p53) in its transcriptional activity and regulation by the E3 ligase Mdm2, in comparison with that of human p53 (h-p53). p-p53 is highly homologous to h-p53 with the N-terminal region showing relative divergence. p-p53 exhibits a comparable transcriptional activity to that of h-p53 towards a diverse range of known target genes, and is subject to ubiquitination and degradation by both human and porcine Mdm2 (h-/p-Mdm2). Utilization of the h-Mdm2 targeting compound Nutlin-3 and protein RPL11 inhibits the negative effect of p-Mdm2 on p-p53. These results suggest that the transcription activity and regulation of p-p53 is very similar to that of h-p53, and that the developed agents targeting the h-p53 pathway could be used in the study of p53 related processes and diseases in pigs.


Assuntos
Regulação da Expressão Gênica/fisiologia , Genes p53 , Proteínas Proto-Oncogênicas c-mdm2/fisiologia , Animais , Linhagem Celular , Humanos , Camundongos , Suínos
8.
Zhonghua Yi Xue Za Zhi ; 100(11): 823-827, 2020 Mar 24.
Artigo em Chinês | MEDLINE | ID: mdl-32234152

RESUMO

Objective: To observe the role of cerebrospinal fluid (CSF) TP53 gene mutation in lung cancer associated meningitis. Methods: A retrospective analysis was performed on 35 patients diagnosed with lung cancer associated meningitis at the Second Hospital of Hebei Medical University from December 2015 to December 2018.All patients underwent the next-generation sequencing of CSF, and TP53 gene was found to be mutant or wild type, including 23 patients with TP53 mutant type and 12 patients with TP53 wild type. The clinical characteristics, CSF leukocyte, protein, glucose, chloride, Karnofsky performance (KPS) and overall survival were observed. Results: Headache, nausea and vomiting were the main clinical manifestations in both groups.There were no significant differences in CSF pressure, leukocyte, biochemical indicators and KPS between the two groups. The average time from diagnosis of lung cancer to diagnosis of lung cancer associated meningitis in the TP53 mutant group was significantly shorter than that in the TP53 wild type group (5.79 months vs 25.5 months).The median survival time of patients in the TP53 mutant group from lung cancer diagnosis to the observation endpoint was 19.77 months, while it was 88.73 months in the TP53 wild type group, and the difference was statistically significant (P=0.043). Conclusions: Mutation in the tumor suppressor gene TP53 can be detected in the CSF of patients with lung cancer associated meningitis. Patients with such mutation have earlier meningeal metastasis and shorter median survival time.


Assuntos
Neoplasias Pulmonares , Meningite , Mutação , Proteína Supressora de Tumor p53/genética , Líquido Cefalorraquidiano , Genes p53 , Humanos , Neoplasias Pulmonares/complicações , Neoplasias Pulmonares/genética , Meningite/complicações , Meningite/genética , Metástase Neoplásica , Prognóstico , Estudos Retrospectivos , Análise de Sobrevida
9.
Proc Natl Acad Sci U S A ; 117(19): 10541-10546, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32332169

RESUMO

Mild replication stress enhances appearance of dozens of robust recurrent genomic break clusters, termed RDCs, in cultured primary mouse neural stem and progenitor cells (NSPCs). Robust RDCs occur within genes ("RDC-genes") that are long and have roles in neural cell communications and/or have been implicated in neuropsychiatric diseases or cancer. We sought to develop an in vitro approach to determine whether specific RDC formation is associated with neural development. For this purpose, we adapted a system to induce neural progenitor cell (NPC) development from mouse embryonic stem cell (ESC) lines deficient for XRCC4 plus p53, a genotype that enhances DNA double-strand break (DSB) persistence to enhance detection. We tested for RDCs by our genome-wide DSB identification approach that captures DSBs via their ability to join to specific genomic Cas9/single-guide RNA-generated bait DSBs. In XRCC4/p53-deficient ESCs, we detected seven RDCs, all of which were in genes and two of which were robust. In contrast, in NPCs derived from these ESC lines we detected 29 RDCs, a large fraction of which were robust and associated with long, transcribed neural genes that were also robust RDC-genes in primary NSPCs. These studies suggest that many RDCs present in NSPCs are developmentally influenced to occur in this cell type and indicate that induced development of NPCs from ESCs provides an approach to rapidly elucidate mechanistic aspects of NPC RDC formation.


Assuntos
Diferenciação Celular/genética , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Neurais/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Quebras de DNA , Replicação do DNA/genética , Proteínas de Ligação a DNA/genética , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Genes p53/genética , Genoma , Humanos , Camundongos , Células-Tronco Embrionárias Murinas/metabolismo , Família Multigênica/genética , Neurogênese , Neurônios/citologia
10.
Anticancer Res ; 40(3): 1535-1542, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32132054

RESUMO

BACKGROUND/AIM: Sessile serrated polyps without dysplasia (SSPND) are characterized by crypts with serrated epithelium, albeit with irregular, corrupted shapes (CCS). PATIENTS AND METHODS: Cell proliferation was explored in the CCS from 60 SSPND and in the crypts from 12 normal colons. Sections were immuno-stained with the Ki-67 proliferation-cell (PC) marker, and with the p53 tumour-suppressor gene. RESULTS: Three predominant PC-phenotypes were found in the CCS from the 60 SSPND: 44 (73.3%) exhibited ectopic, asymmetric, randomly distributed PC-clusters, 12 (20.0%), continuous PC in one or in both slopes of the crypts, and in the remaining 4 (6.7%), single, randomly distributed PC were recorded. In contrast, the scrutiny of more than 200,000 normal colon crypts (controls) showed symmetrically aligned PC, restricted to the lower third of the crypts. p53-up-regulation in CCS was recorded in 11(18.3%) of the 60 NDSSP, but in none of the normal crypts in the 12 controls. CONCLUSION: The non-dysplastic epithelium that lines CCS in SSPND coexists with an asymmetric relocation of the PC-domains. In addition, the CCS in nearly one-fifth of the SSPND exhibited p53-up-regulated cells. Taken together, the non-dysplastic CCS epithelium in SSPND thrives with somatic mutations. The accretion of putative mutated non-dysplastic CCS might be a crucial event in the evolution of colonic SSPND towards sessile serrated adenomas.


Assuntos
Pólipos do Colo/patologia , Proliferação de Células/fisiologia , Forma Celular/fisiologia , Pólipos do Colo/genética , Pólipos do Colo/metabolismo , Genes p53 , Humanos , Imunoensaio , Fenótipo , Proteína Supressora de Tumor p53/biossíntese , Proteína Supressora de Tumor p53/genética , Regulação para Cima
11.
Nat Commun ; 11(1): 1509, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198346

RESUMO

Nonsense mutations cause about 10% of genetic disease cases, and no treatments are available. Nonsense mutations can be corrected by molecules with nonsense mutation readthrough activity. An extract of the mushroom Lepista inversa has recently shown high-efficiency correction of UGA and UAA nonsense mutations. One active constituent of this extract is 2,6-diaminopurine (DAP). In Calu-6 cancer cells, in which TP53 gene has a UGA nonsense mutation, DAP treatment increases p53 level. It also decreases the growth of tumors arising from Calu-6 cells injected into immunodeficient nude mice. DAP acts by interfering with the activity of a tRNA-specific 2'-O-methyltransferase (FTSJ1) responsible for cytosine 34 modification in tRNATrp. Low-toxicity and high-efficiency UGA nonsense mutation correction make DAP a good candidate for the development of treatments for genetic diseases caused by nonsense mutations.


Assuntos
2-Aminopurina/análogos & derivados , 2-Aminopurina/farmacologia , Códon sem Sentido/efeitos dos fármacos , Descoberta de Drogas , Ensaios de Seleção de Medicamentos Antitumorais , Mutação/efeitos dos fármacos , Animais , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Genes p53/genética , Células HEK293 , Células HeLa , Humanos , Lepisma/química , Camundongos , Camundongos Nus , RNA de Transferência/genética , tRNA Metiltransferases/metabolismo
13.
Cancer Res ; 80(8): 1720-1734, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32015093

RESUMO

The molecular background of hepatocellular carcinoma (HCC) is highly heterogeneous, and biomarkers predicting response to treatments are an unmet clinical need. We investigated miR-30e-3p contribution to HCC phenotype and response to sorafenib, as well as the mutual modulation of TP53/MDM2 pathway, in HCC tissues and preclinical models. MiR-30e-3p was downregulated in human and rat HCCs, and its downregulation associated with TP53 mutations. TP53 contributed to miR-30e-3p biogenesis, and MDM2 was identified among its target genes, establishing an miR-30e-3p/TP53/MDM2 feedforward loop and accounting for miR-30e-3p dual role based on TP53 status. EpCAM, PTEN, and p27 were demonstrated as miR-30e-3p additional targets mediating its contribution to stemness and malignant features. In a preliminary cohort of patients with HCC treated with sorafenib, increased miR-30e-3p circulating levels predicted the development of resistance. In conclusion, molecular background dictates miR-30e-3p dual behavior in HCC. Mdm2 targeting plays a predominant tumor suppressor function in wild-type TP53 contexts, whereas other targets such as PTEN, p27, and EpCAM gain relevance and mediate miR-30e-3p oncogenic role in nonfunctional TP53 backgrounds. Increased circulating levels of miR-30e-3p predict the development of sorafenib resistance in a preliminary series of patients with HCC and deserve future investigations. SIGNIFICANCE: The dual role of miR-30e-3p in HCC clarifies how the molecular context dictates the tumor suppressor or oncogenic function played by miRNAs.


Assuntos
Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , MicroRNAs/fisiologia , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Antineoplásicos/farmacologia , Sítios de Ligação , Carcinógenos , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Proliferação de Células , Estudos de Coortes , Dietilnitrosamina , Modelos Animais de Doenças , Regulação para Baixo , Resistencia a Medicamentos Antineoplásicos , Molécula de Adesão da Célula Epitelial/metabolismo , Inativação Gênica , Genes Supressores de Tumor , Genes p53/genética , Células Hep G2 , Xenoenxertos , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , MicroRNAs/metabolismo , Mutação , Invasividade Neoplásica , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Células-Tronco Neoplásicas , PTEN Fosfo-Hidrolase/metabolismo , Fenótipo , Antígeno Nuclear de Célula em Proliferação/metabolismo , Proteínas Proto-Oncogênicas c-mdm2/genética , Ratos , Sorafenibe/farmacologia , Análise Serial de Tecidos , Proteína Supressora de Tumor p53/genética
14.
Cancer Res ; 80(8): 1669-1680, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32060145

RESUMO

The role of the ataxia-telangiectasia-mutated (ATM) gene in human malignancies, especially in solid tumors, remains poorly understood. In the present study, we explored the involvement of ATM in transforming primary human cells into cancer stem cells. We show that ATM plays an unexpected role in facilitating oncogene-induced malignant transformation through transcriptional reprogramming. Exogenous expression of an oncogene cocktail induced a significant amount of DNA double-strand breaks in human fibroblasts that caused persistent activation of ATM, which in turn enabled global transcriptional reprogramming through chromatin relaxation, allowing oncogenic transcription factors to access chromatin. Consistently, deficiencies in ATM significantly attenuated oncogene-induced transformation of human cells. In addition, ATM inhibition significantly reduced tumorigenesis in a mouse model of mammary cancer. ATM and cellular DNA damage response therefore play a previously unknown role in facilitating rather than suppressing oncogene-induced malignant transformation of mammalian cells. SIGNIFICANCE: These findings uncover a novel pro-oncogenic role for ATM and show that contrary to established theory, ATM does not always function as a tumor suppressor; its function is however dependent on cell type.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Transformação Celular Neoplásica/genética , Reprogramação Celular/genética , Quebras de DNA de Cadeia Dupla , Reparo do DNA/fisiologia , Células-Tronco Neoplásicas/patologia , Animais , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/deficiência , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Linhagem Celular , Transformação Celular Neoplásica/patologia , Cromatina/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Feminino , Fibroblastos/patologia , Técnicas de Inativação de Genes , Marcação de Genes/métodos , Genes p53 , Humanos , Neoplasias Mamárias Animais/genética , Neoplasias Mamárias Animais/patologia , Camundongos , Camundongos Nus , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/deficiência , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , RNA Mensageiro/metabolismo , Ativação Transcricional , Transcriptoma/fisiologia , Proteína 28 com Motivo Tripartido/genética , Proteína 28 com Motivo Tripartido/metabolismo , Ensaio Tumoral de Célula-Tronco/métodos
17.
Methods Mol Biol ; 2102: 373-394, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31989568

RESUMO

Sputum and plasma can provide noninvasive materials to investigate biomarkers for cancer detection and diagnosis. Mutations in the K-ras oncogene and p53 suppressor gene have been frequently found in sputum and plasma samples collected not only from lung cancer patients but also in those of patients prior to presenting clinical symptoms of lung cancer, suggesting that they may also provide useful biomarkers from early lung cancer diagnosis. However, the detection of these mutations has been complicated by the fact that they often occur in only a small fraction of epithelial cells among sputum cells, and of cell-free DNA present in plasma. This chapter describes methods to isolate low fraction epithelial cells from sputum and cell-free DNA from plasma samples obtained from lung cancer patients and to identify low fraction K-ras and p53 mutations in these samples.


Assuntos
DNA Tumoral Circulante/sangue , Análise Mutacional de DNA/métodos , DNA de Neoplasias/genética , Genes p53/genética , Neoplasias Pulmonares/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Escarro/química , DNA de Neoplasias/análise , DNA de Neoplasias/química , DNA de Neoplasias/isolamento & purificação , Células Epiteliais/química , Genes ras , Humanos , Mutação , Mutação Puntual , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Escarro/citologia , Fluxo de Trabalho
18.
BMC Cancer ; 20(1): 3, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31898537

RESUMO

BACKGROUND: Ewing sarcoma is a malignancy of primitive cells, possibly of mesenchymal origin. It is probable that genetic perturbations other than EWS-FLI1 cooperate with it to produce the tumor. Sequencing studies identified STAG2 mutations in approximately 15% of cases in humans. In the present study, we hypothesize that loss of Stag2 cooperates with EWS-FLI1 in generating sarcomas derived from murine mesenchymal stem cells (MSCs). METHODS: Mice bearing an inducible EWS-FLI1 transgene were crossed to p53-/- mice in pure C57/Bl6 background. MSCs were derived from the bone marrow of the mice. EWS-FLI1 induction and Stag2 knockdown were achieved in vitro by adenovirus-Cre and shRNA-bearing pGIPZ lentiviral infection, respectively. The cells were then treated with ionizing radiation to 10 Gy. Anchorage independent growth in vitro was assessed by soft agar assays. Cellular migration and invasion were evaluated by transwell assays. Cells were injected with Matrigel intramuscularly into C57/Bl6 mice to test for tumor formation. RESULTS: Primary murine MSCs with the genotype EWS-FLI1 p53-/- were resistant to transformation and did not form tumors in syngeneic mice without irradiation. Stag2 inhibition increased the efficiency and speed of sarcoma formation significantly in irradiated EWS-FLI1 p53-/- MSCs. The efficiency of tumor formation was 91% for cells in mice injected with Stag2-repressed cells and 22% for mice receiving cells without Stag2 inhibition (p < .001). Stag2 knockdown reduced survival of mice in Kaplan-Meier analysis (p < .001). It also increased MSC migration and invasion in vitro but did not affect proliferation rate or aneuploidy. CONCLUSION: Loss of Stag2 has a synergistic effect with EWS-FLI1 in the production of sarcomas from murine MSCs, but the mechanism may not relate to increased proliferation or chromosomal instability. Primary murine MSCs are resistant to transformation, and the combination of p53 null mutation, EWS-FLI1, and Stag2 inhibition does not confer immediate conversion of MSCs to sarcomas. Irradiation is necessary in this model, suggesting that perturbations of other genes beside Stag2 and p53 are likely to be essential in the development of EWS-FLI1-driven sarcomas from MSCs.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Células-Tronco Mesenquimais/metabolismo , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Proteína Proto-Oncogênica c-fli-1/genética , Proteína Proto-Oncogênica c-fli-1/metabolismo , Proteína EWS de Ligação a RNA/genética , Proteína EWS de Ligação a RNA/metabolismo , Animais , Ciclo Celular/genética , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células , Aberrações Cromossômicas , Modelos Animais de Doenças , Expressão Gênica , Genes p53 , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Interferência de RNA , Sarcoma de Ewing/etiologia , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/patologia
19.
Virchows Arch ; 476(1): 147-157, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31741049

RESUMO

Bone tumours are difficult to diagnose and treat, as they are rare and over 60 different subtypes are recognised. The emergence of next-generation sequencing has partly elucidated the molecular mechanisms behind these tumours, including the group of bone forming tumours (osteoma, osteoid osteoma, osteoblastoma and osteosarcoma). Increased knowledge on the molecular mechanism could help to identify novel diagnostic markers and/or treatment options. Osteoid osteoma and osteoblastoma are bone forming tumours without malignant potential that have overlapping morphology. They were recently shown to carry FOS and-to a lesser extent-FOSB rearrangements suggesting that these tumours are closely related. The presence of these rearrangements could help discriminate these entities from other lesions with woven bone deposition. Osteosarcoma is a malignant bone forming tumour for which different histological subtypes are recognised. High-grade osteosarcoma is the prototype of a complex karyotype tumour, and extensive research exploring its molecular background has identified phenomena like chromothripsis and kataegis and some recurrent alterations. Due to lack of specificity, this has not led to a valuable novel diagnostic marker so far. Nevertheless, these studies have also pointed towards potential targetable drivers of which the therapeutic merit remains to be further explored.


Assuntos
Neoplasias Ósseas/patologia , Osteoblastoma/patologia , Osteoma Osteoide/patologia , Osteossarcoma/patologia , Neoplasias Ósseas/genética , Rearranjo Gênico , Genes p53 , Predisposição Genética para Doença , Humanos , Osteoblastoma/genética , Osteoma/genética , Osteoma/patologia , Osteoma Osteoide/genética , Proteína do Retinoblastoma/genética
20.
Oncology ; 98(4): 222-229, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31846968

RESUMO

INTRODUCTION: Next-generation sequencing (NGS) with molecular barcodes (MB) is a novel method that enables the highly sensitive detection of circulating tumor DNA (ctDNA) in a relatively wide range of genes. OBJECTIVE: The aim of this study was to examine the utility of NGS with MB for detecting ctDNA in patients with esophageal squamous cell carcinoma (ESCC). METHODS: Five patients with ESCC who underwent preoperative treatment followed by esophagectomy were examined. The frequency of TP53 mutations in DNA extracted from tumor tissue and plasma at each time point during the treatment course was analyzed using NGS without MB. In 1 patient, additional analysis using NGS with MB was conducted to compare the sensitivities and to evaluate the clinical utility of this novel method. RESULTS: TP53 mutations in tumor tissue were identified in 3 of 5 patients with ESCC. In 1 patient, the mutational allele frequency in plasma was 1.97% before preoperative treatment, and decreased to 0.09% after preoperative treatment. As the maximum frequency of background errors were 3.22% using NGS without MB and 0.08% with MB, which indicated that the sensitivity of ctDNA detection using NGS with MB was much higher than without MB. In 1 patient who had recurrence half a year after surgery, only NGS with MB could detect ctDNA even at 4 weeks after surgery, at a frequency of 0.20%. CONCLUSIONS: NGS with MB enabled comprehensive and highly sensitive detection of ctDNA in a patient with ESCC. This novel method may be useful for the clinical diagnosis of ESCC.


Assuntos
DNA Tumoral Circulante/sangue , Código de Barras de DNA Taxonômico/métodos , Neoplasias Esofágicas/genética , Carcinoma de Células Escamosas do Esôfago/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Idoso , Genes p53 , Humanos , Masculino , Pessoa de Meia-Idade , Mutação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA