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1.
Dev Cell ; 56(24): 3364-3379.e10, 2021 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-34852214

RESUMO

Failure to reorganize the endoplasmic reticulum (ER) in mitosis results in chromosome missegregation. Here, we show that accurate chromosome segregation in human cells requires cell cycle-regulated ER membrane production. Excess ER membranes increase the viscosity of the mitotic cytoplasm to physically restrict chromosome movements, which impedes the correction of mitotic errors leading to the formation of micronuclei. Mechanistically, we demonstrate that the protein phosphatase CTDNEP1 counteracts mTOR kinase to establish a dephosphorylated pool of the phosphatidic acid phosphatase lipin 1 in interphase. CTDNEP1 control of lipin 1 limits the synthesis of fatty acids for ER membrane biogenesis in interphase that then protects against chromosome missegregation in mitosis. Thus, regulation of ER size can dictate the biophysical properties of mitotic cells, providing an explanation for why ER reorganization is necessary for mitotic fidelity. Our data further suggest that dysregulated lipid metabolism is a potential source of aneuploidy in cancer cells.


Assuntos
Ciclo Celular , Segregação de Cromossomos , Retículo Endoplasmático/metabolismo , Linhagem Celular , Ácidos Graxos/biossíntese , Humanos , Metáfase , Micronúcleo Germinativo/metabolismo , Mitose , Modelos Biológicos , Fosfatidato Fosfatase/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Fosforilação , Serina-Treonina Quinases TOR/metabolismo , Viscosidade
2.
Proc Natl Acad Sci U S A ; 118(48)2021 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-34819364

RESUMO

Mitotic errors can activate cyclic GMP-AMP synthase (cGAS) and induce type I interferon (IFN) signaling. Current models propose that chromosome segregation errors generate micronuclei whose rupture activates cGAS. We used a panel of antimitotic drugs to perturb mitosis in human fibroblasts and measured abnormal nuclear morphologies, cGAS localization, and IFN signaling in the subsequent interphase. Micronuclei consistently recruited cGAS without activating it. Instead, IFN signaling correlated with formation of cGAS-coated chromatin bridges that were selectively generated by microtubule stabilizers and MPS1 inhibitors. cGAS activation by chromatin bridges was suppressed by drugs that prevented cytokinesis. We confirmed cGAS activation by chromatin bridges in cancer lines that are unable to secrete IFN by measuring paracrine transfer of 2'3'-cGAMP to fibroblasts, and in mouse cells. We propose that cGAS is selectively activated by self-chromatin when it is stretched in chromatin bridges. Immunosurveillance of cells that fail mitosis, and antitumor actions of taxanes and MPS1 inhibitors, may depend on this effect.


Assuntos
Cromatina/fisiologia , Mitose/fisiologia , Nucleotidiltransferases/metabolismo , Linhagem Celular Tumoral , Cromatina/genética , Humanos , Interferon Tipo I/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/genética , Micronúcleo Germinativo/genética , Micronúcleo Germinativo/fisiologia , Mitose/efeitos dos fármacos , Mitose/genética , Neoplasias/metabolismo , Nucleotídeos Cíclicos/metabolismo , Nucleotidiltransferases/genética , Nucleotidiltransferases/fisiologia , Transdução de Sinais
3.
Cell ; 184(22): 5506-5526, 2021 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-34715021

RESUMO

Endogenous cytoplasmic DNA (cytoDNA) species are emerging as key mediators of inflammation in diverse physiological and pathological contexts. Although the role of endogenous cytoDNA in innate immune activation is well established, the cytoDNA species themselves are often poorly characterized and difficult to distinguish, and their mechanisms of formation, scope of function and contribution to disease are incompletely understood. Here, we summarize current knowledge in this rapidly progressing field with emphases on similarities and differences between distinct cytoDNAs, their underlying molecular mechanisms of formation and function, interactions between cytoDNA pathways, and therapeutic opportunities in the treatment of age-associated diseases.


Assuntos
Envelhecimento/metabolismo , Citoplasma/metabolismo , DNA/metabolismo , Doença , Animais , Humanos , Micronúcleo Germinativo/metabolismo , Retroelementos/genética
4.
J Cell Biol ; 220(12)2021 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-34613334

RESUMO

Cycling cells must respond to DNA double-strand breaks (DSBs) to avoid genome instability. Missegregation of chromosomes with DSBs during mitosis results in micronuclei, aberrant structures linked to disease. How cells respond to DSBs during mitosis is incompletely understood. We previously showed that Drosophilamelanogaster papillar cells lack DSB checkpoints (as observed in many cancer cells). Here, we show that papillar cells still recruit early acting repair machinery (Mre11 and RPA3) and the Fanconi anemia (FA) protein Fancd2 to DSBs. These proteins persist as foci on DSBs as cells enter mitosis. Repair foci are resolved in a stepwise manner during mitosis. DSB repair kinetics depends on both monoubiquitination of Fancd2 and the alternative end-joining protein DNA polymerase θ. Disruption of either or both of these factors causes micronuclei after DNA damage, which disrupts intestinal organogenesis. This study reveals a mechanism for how cells with inactive DSB checkpoints can respond to DNA damage that persists into mitosis.


Assuntos
Quebra Cromossômica , Segregação de Cromossomos , Dano ao DNA , DNA Polimerase Dirigida por DNA/metabolismo , Drosophila melanogaster/metabolismo , Transdução de Sinais , Animais , Quebras de DNA de Cadeia Dupla , Drosophila melanogaster/citologia , Drosophila melanogaster/genética , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/genética , Testes Genéticos , Micronúcleo Germinativo/metabolismo , Mitose , Mutação/genética , Ubiquitinação , DNA Polimerase teta
5.
J Radiat Res ; 62(4): 618-625, 2021 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-33912960

RESUMO

Metformin, a first-line oral drug for type II diabetes mellitus, not only reduces blood glucose levels, but also has many other biological effects. Recent studies have been conducted to determine the protective effect of metformin in irradiation injuries. However, the results are controversial and mainly focus on the time of metformin administration. In this study, we aimed to investigate the protective effect of metformin in BALB/c mice exposed to 6 Gy or 8 Gy of a 60Co source of γ-rays for total body irradiation (TBI). Survival outcomes were assessed following exposure to 8 Gy or 6 Gy TBI, and hematopoietic damage and intestinal injury were assessed after exposure to 6 Gy TBI. Metformin prolonged the survival of mice exposed to 8 Gy TBI and improved the survival rate of mice exposed to 6 Gy TBI only when administered before exposure to irradiation. Moreover, pretreatment with metformin reduced the frequency of micronuclei (MN) in the bone marrow of mice exposed to 6 Gy TBI. Pretreatment of metformin also protected the intestinal morphology of mice, reduced inflammatory response and decreased the number of apoptotic cells in intestine. In conclusion, we demonstrated that pretreatment with metformin could alleviate irradiation injury.


Assuntos
Metformina/farmacologia , Irradiação Corporal Total , Animais , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Hematopoese/efeitos dos fármacos , Hematopoese/efeitos da radiação , Intestinos/patologia , Intestinos/efeitos da radiação , Masculino , Camundongos Endogâmicos BALB C , Micronúcleo Germinativo/metabolismo , Análise de Sobrevida
6.
Nat Genet ; 53(6): 895-905, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33846636

RESUMO

Genome editing has therapeutic potential for treating genetic diseases and cancer. However, the currently most practicable approaches rely on the generation of DNA double-strand breaks (DSBs), which can give rise to a poorly characterized spectrum of chromosome structural abnormalities. Here, using model cells and single-cell whole-genome sequencing, as well as by editing at a clinically relevant locus in clinically relevant cells, we show that CRISPR-Cas9 editing generates structural defects of the nucleus, micronuclei and chromosome bridges, which initiate a mutational process called chromothripsis. Chromothripsis is extensive chromosome rearrangement restricted to one or a few chromosomes that can cause human congenital disease and cancer. These results demonstrate that chromothripsis is a previously unappreciated on-target consequence of CRISPR-Cas9-generated DSBs. As genome editing is implemented in the clinic, the potential for extensive chromosomal rearrangements should be considered and monitored.


Assuntos
Sistemas CRISPR-Cas/genética , Cromotripsia , Edição de Genes , Anemia Falciforme/genética , Antígenos CD34/metabolismo , Proteína 9 Associada à CRISPR/metabolismo , Divisão Celular , Cromossomos Humanos/genética , Clivagem do DNA , Genoma Humano , Humanos , Micronúcleo Germinativo/genética , Proteína Supressora de Tumor p53/metabolismo
7.
J Cell Physiol ; 236(5): 3579-3598, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33078399

RESUMO

Genome instability in cancer drives tumor heterogeneity, undermines the success of therapies, and leads to metastasis and recurrence. Condensins are conserved chromatin-binding proteins that promote genomic stability, mainly by ensuring proper condensation of chromatin and mitotic chromosome segregation. Condensin mutations are found in human tumors, but it is not known how or even if such mutations promote cancer progression. In this study, we focus on condensin II subunit CAPH2 and specific CAPH2 mutations reported to be enriched in human cancer patients, and we test how CAPH2 cancer-specific mutations may lead to condensin II complex dysfunction and contribute to genome instability. We find that R551P, R551S, and S556F mutations in CAPH2 cause genomic instability by causing DNA damage, anaphase defects, micronuclei, and chromosomal instability. DNA damage and anaphase defects are caused primarily by ataxia telangiectasia and Rad3-related-dependent telomere dysfunction, as anaphase bridges are enriched for telomeric repeat sequences. We also show that these mutations decrease the binding of CAPH2 to the ATPase subunit SMC4 as well as the rest of the condensin II complex, and decrease the amount of CAPH2 protein bound to chromatin. Thus, in vivo the R551P, R551S, and S556F cancer-specific CAPH2 mutant proteins are likely to impair condensin II complex formation, impede condensin II activity during mitosis and interphase, and promote genetic heterogeneity in cell populations that can lead to clonal outgrowth of cancer cells with highly diverse genotypes.


Assuntos
Adenosina Trifosfatases/genética , Anáfase , Proteínas de Ciclo Celular/metabolismo , Cromossomos Humanos/metabolismo , Proteínas de Ligação a DNA/genética , Instabilidade Genômica , Complexos Multiproteicos/genética , Mutação/genética , Neoplasias/genética , Proteínas Nucleares/metabolismo , Telômero/patologia , Adenosina Trifosfatases/química , Adenosina Trifosfatases/metabolismo , Sequência de Aminoácidos , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Cromatina/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Dano ao DNA , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Humanos , Micronúcleo Germinativo/metabolismo , Complexos Multiproteicos/química , Complexos Multiproteicos/metabolismo , Proteínas Mutantes/metabolismo , Neoplasias/patologia , Proteínas Nucleares/química , Proteínas Nucleares/genética , Ligação Proteica , Estabilidade Proteica , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Fase S , Telômero/metabolismo
8.
Chem Biol Interact ; 332: 109283, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33035519

RESUMO

1-Methylpyrene (1-MP) is a ubiquitous environmental pollutant and rodent carcinogen. Its mutagenic activity depends on sequential activation by various CYP and sulfotransferase (SULT) enzymes. Previously we have observed induction of micronuclei and mitotic arrest by 1-MP in a Chinese hamster (V79)-derived cell line expressing both human CYP1A2 and SULT1A1 (V79-hCYP1A2-hSULT1A1), however, the mode of chromosome damage and the involvement of mitotic tubulin structures have not been clarified. In this study, we used immunofluorescent staining of centromere protein B (CENP-B) with the formed micronuclei, and that of ß- and γ-tubulin reflecting the structures of mitotic spindle and centrioles, respectively, in V79-hCYP1A2-hSULT1A1 cells. The results indicated that 1-MP induced micronuclei in V79-hCYP1A2-hSULT1A1 cells from 0.125 to 2 µM under a 24 h/0 h (exposure/recovery) regime, while in the parental V79-Mz cells micronuclei were induced by 1-MP only at concentrations ≥ 8 µM; in both cases, the micronuclei induced by 1-MP were predominantly CENP-B positive. Following 54 h of exposure, 1-MP induced mitotic spindle non-congression and centrosome amplification (multipolar mitosis) in V79-hCYP1A2-hSULT1A1 cells, and anaphase/telophase retardation, at concentrations ≥ 0.125 µM with concentration-dependence; while in V79-Mz cells it was inactive up to 8 µM. This study suggests that in mammalian cells proficient in activating enzymes 1-MP may induce chromosome loss and mitotic disturbance, probably by interfering with the mitotic spindle and centrioles.


Assuntos
Arilsulfotransferase/metabolismo , Cromossomos de Mamíferos/metabolismo , Citocromo P-450 CYP1A2/metabolismo , Mitose/efeitos dos fármacos , Pirenos/farmacologia , Animais , Linhagem Celular , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Proteína B de Centrômero/metabolismo , Cricetinae , Humanos , Micronúcleo Germinativo/efeitos dos fármacos , Micronúcleo Germinativo/metabolismo , Índice Mitótico , Fuso Acromático/efeitos dos fármacos , Fuso Acromático/metabolismo
9.
Annu Rev Cell Dev Biol ; 36: 85-114, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32692592

RESUMO

The nuclear envelope is often depicted as a static barrier that regulates access between the nucleus and the cytosol. However, recent research has identified many conditions in cultured cells and in vivo in which nuclear membrane ruptures cause the loss of nuclear compartmentalization. These conditions include some that are commonly associated with human disease, such as migration of cancer cells through small spaces and expression of nuclear lamin disease mutations in both cultured cells and tissues undergoing nuclear migration. Nuclear membrane ruptures are rapidly repaired in the nucleus but persist in nuclear compartments that form around missegregated chromosomes called micronuclei. This review summarizes what is known about the mechanisms of nuclear membrane rupture and repair in both the main nucleus and micronuclei, and highlights recent work connecting the loss of nuclear integrity to genome instability and innate immune signaling. These connections link nuclear membrane rupture to complex chromosome alterations, tumorigenesis, and laminopathy etiologies.


Assuntos
Membrana Nuclear/patologia , Animais , Instabilidade Genômica , Humanos , Imunidade Inata , Micronúcleo Germinativo/metabolismo , Modelos Biológicos , Membrana Nuclear/metabolismo
10.
J Radiat Res ; 61(1): 1-13, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31845986

RESUMO

Human oxidation resistance 1 (OXR1) was identified as a protein that decreases genomic mutations in Escherichia coli caused by oxidative DNA damage. However, the mechanism by which OXR1 defends against genome instability has not been elucidated. To clarify how OXR1 maintains genome stability, the effects of OXR1-depletion on genome stability were investigated in OXR1-depleted HeLa cells using gamma-rays (γ-rays). The OXR1-depleted cells had higher levels of superoxide and micronucleus (MN) formation than control cells after irradiation. OXR1-overexpression alleviated the increases in reactive oxygen species (ROS) level and MN formation after irradiation. The increased MN formation in irradiated OXR1-depleted cells was partially attenuated by the ROS inhibitor N-acetyl-L-cysteine, suggesting that OXR1-depeletion increases ROS-dependent genome instability. We also found that OXR1-depletion shortened the duration of γ-ray-induced G2/M arrest. In the presence of the cell cycle checkpoint inhibitor caffeine, the level of MN formed after irradiation was similar between control and OXR1-depleted cells, demonstrating that OXR1-depletion accelerates MN formation through abrogation of G2/M arrest. In OXR1-depleted cells, the level of cyclin D1 protein expression was increased. Here we report that OXR1 prevents genome instability by cell cycle regulation as well as oxidative stress defense.


Assuntos
Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos da radiação , Raios gama , Instabilidade Genômica/efeitos da radiação , Proteínas Mitocondriais/metabolismo , Mitose/efeitos da radiação , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Instabilidade Genômica/efeitos dos fármacos , Células HeLa , Humanos , Peróxido de Hidrogênio/toxicidade , Micronúcleo Germinativo/efeitos dos fármacos , Micronúcleo Germinativo/metabolismo , Micronúcleo Germinativo/efeitos da radiação , Proteínas Mitocondriais/deficiência , Mitose/efeitos dos fármacos , Modelos Biológicos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Superóxidos/metabolismo
11.
Sci Rep ; 9(1): 11845, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31413286

RESUMO

Ultrasound (US) induced transient membrane permeabilisation has emerged as a hugely promising tool for the delivery of exogenous vectors through the cytoplasmic membrane, paving the way to the design of novel anticancer strategies by targeting functional nanomaterials to specific biological sites. An essential step towards this end is the detailed recognition of suitably marked nanoparticles in sonoporated cells and the investigation of the potential related biological effects. By taking advantage of Synchrotron Radiation Fourier Transform Infrared micro-spectroscopy (SR-microFTIR) in providing highly sensitive analysis at the single cell level, we studied the internalisation of a nanoprobe within fibroblasts (NIH-3T3) promoted by low-intensity US. To this aim we employed 20 nm gold nanoparticles conjugated with the IR marker 4-aminothiophenol. The significant Surface Enhanced Infrared Absorption provided by the nanoprobes, with an absorbance increase up to two orders of magnitude, allowed us to efficiently recognise their inclusion within cells. Notably, the selective and stable SR-microFTIR detection from single cells that have internalised the nanoprobe exhibited clear changes in both shape and intensity of the spectral profile, highlighting the occurrence of biological effects. Flow cytometry, immunofluorescence and murine cytokinesis-block micronucleus assays confirmed the presence of slight but significant cytotoxic and genotoxic events associated with the US-nanoprobe combined treatments. Our results can provide novel hints towards US and nanomedicine combined strategies for cell spectral imaging as well as drug delivery-based therapies.


Assuntos
Fibroblastos/metabolismo , Ouro/química , Raios Infravermelhos , Nanopartículas Metálicas/química , Análise de Célula Única , Síncrotrons , Ultrassonografia , Animais , Sobrevivência Celular , Camundongos , Micronúcleo Germinativo/metabolismo , Células NIH 3T3 , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
12.
Genes (Basel) ; 10(5)2019 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-31086101

RESUMO

Micronuclei research has regained its popularity due to the realization that genome chaos, a rapid and massive genome re-organization under stress, represents a major common mechanism for punctuated cancer evolution. The molecular link between micronuclei and chromothripsis (one subtype of genome chaos which has a selection advantage due to the limited local scales of chromosome re-organization), has recently become a hot topic, especially since the link between micronuclei and immune activation has been identified. Many diverse molecular mechanisms have been illustrated to explain the causative relationship between micronuclei and genome chaos. However, the newly revealed complexity also causes confusion regarding the common mechanisms of micronuclei and their impact on genomic systems. To make sense of these diverse and even conflicting observations, the genome theory is applied in order to explain a stress mediated common mechanism of the generation of micronuclei and their contribution to somatic evolution by altering the original set of information and system inheritance in which cellular selection functions. To achieve this goal, a history and a current new trend of micronuclei research is briefly reviewed, followed by a review of arising key issues essential in advancing the field, including the re-classification of micronuclei and how to unify diverse molecular characterizations. The mechanistic understanding of micronuclei and their biological function is re-examined based on the genome theory. Specifically, such analyses propose that micronuclei represent an effective way in changing the system inheritance by altering the coding of chromosomes, which belongs to the common evolutionary mechanism of cellular adaptation and its trade-off. Further studies of the role of micronuclei in disease need to be focused on the behavior of the adaptive system rather than specific molecular mechanisms that generate micronuclei. This new model can clarify issues important to stress induced micronuclei and genome instability, the formation and maintenance of genomic information, and cellular evolution essential in many common and complex diseases such as cancer.


Assuntos
Instabilidade Genômica/genética , Micronúcleo Germinativo/genética , Micronúcleo Germinativo/fisiologia , Aberrações Cromossômicas/classificação , Cromotripsia , Bases de Dados Genéticas , Evolução Molecular , Genoma/genética , Instabilidade Genômica/fisiologia , Genômica/métodos , Hereditariedade/genética , Humanos , Neoplasias/genética , Testamentos
13.
Methods Enzymol ; 612: 101-126, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30502938

RESUMO

We present here methods to study a eukaryotic microorganism with two nuclear genomes, both originating from the same zygotic genome. Paramecium, like other ciliates, is characterized by nuclear dimorphism, which is the presence of two types of nuclei with distinct organization and functions in the same cytoplasm. The two diploid germline micronuclei (MIC) undergo meiosis and fertilization to transmit the genetic information across sexual generations. The highly polyploid somatic macronucleus (MAC) contains a reduced version of the genome optimized for gene expression. Reproducible programmed DNA elimination of about 30% of the complexity of the 100Mb MIC genome occurs during development of the MAC along with endoreplication to 800 copies. Large regions that contain transposable elements and other repeats are eliminated, and short single copy remnants of transposable elements, which often interrupt coding sequences, are precisely excised to restore functional open reading frames. Genome-wide studies of this process require access to MIC DNA which has long been impossible. The breakthrough with respect to this technical obstacle came with development of a MIC purification protocol involving a critical step of flow cytometry to sort nuclei representing only 0.5% of total genomic DNA. Here, we provide a step-by-step protocol and important tips for purifying nuclei, and present the methods developed for downstream analysis of NGS data.


Assuntos
Células Eucarióticas/metabolismo , Estudo de Associação Genômica Ampla/métodos , Macronúcleo/genética , Citometria de Fluxo , Sequenciamento de Nucleotídeos em Larga Escala , Micronúcleo Germinativo/genética
14.
Pancreatology ; 18(6): 647-654, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30055942

RESUMO

BACKGROUND: Precision medicine guided by comprehensive genome sequencing represents a potential treatment strategy for pancreatic cancer. However, clinical sequencing for pancreatic cancer entails several practical difficulties. We have launched an in-house clinical sequencing system and started genomic testing for patients with cancer in clinical practice. We have analyzed the clinical utility of this system in pancreatic cancer. METHODS: We retrospectively reviewed 20 patients with pancreatic cancer who visited our division. Genomic DNA was extracted from both tumor tissue and peripheral blood mononuclear cells obtained from the patients. We performed a comprehensive genomic testing using targeted amplicon sequencing for 160 cancer-related genes. The primary endpoints were the detection rates of potential actionable and druggable gene alterations. The secondary endpoints were the detection rate of secondary germline findings, the rate of re-biopsy required for genome sequencing, survival time after the initial visit (post-sequencing survival time), and turnaround time. RESULTS: Although re-biopsy was required for 25% (5/20) of all patients, genomic testing was performed in all patients. Actionable and druggable gene alterations were detected in 100% (20/20) and 35% (7/20) of patients, respectively, whereas secondary germline findings were detected in 5% (1/20) of patients. The median turnaround times for physicians and patients were 20 and 26 days, respectively. The median post-sequencing survival time was 10.3 months. Only 10% (2/20) of all patients were treated with therapeutic agents based on the outcomes of genomic testing. CONCLUSIONS: The clinical application of comprehensive genomic testing for pancreatic cancer was feasible and promising in clinical practice.


Assuntos
Testes Genéticos/métodos , Genômica/métodos , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/genética , Idoso , Idoso de 80 Anos ou mais , Biópsia , DNA de Neoplasias/sangue , Diagnóstico Precoce , Determinação de Ponto Final , Medicina Baseada em Evidências , Feminino , Genes Neoplásicos/efeitos dos fármacos , Genes Neoplásicos/genética , Humanos , Masculino , Micronúcleo Germinativo , Pessoa de Meia-Idade , Monócitos/química , Estadiamento de Neoplasias , Neoplasias Pancreáticas/patologia , Medicina de Precisão , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento
15.
Genes Cells ; 23(7): 568-579, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29882620

RESUMO

Ciliated protozoa possess two morphologically and functionally distinct nuclei: a macronucleus (MAC) and a micronucleus (MIC). The MAC is transcriptionally active and functions in all cellular events. The MIC is transcriptionally inactive during cell growth, but functions in meiotic events to produce progeny nuclei. Thus, these two nuclei must be distinguished by the nuclear proteins required for their distinct functions during cellular events such as cell proliferation and meiosis. To understand the mechanism of the nuclear transport specific to either MAC or MIC, we identified specific nuclear localization signals (NLSs) in two MAC- and MIC-specific nuclear proteins, macronuclear histone H1 and micronuclear linker histone-like protein (Mlh1), respectively. By expressing GFP-fused fragments of these proteins in Tetrahymena thermophila cells, two distinct regions in macronuclear histone H1 protein were assigned as independent MAC-specific NLSs and two distinct regions in Mlh1 protein were assigned as independent MIC-specific NLSs. These NLSs contain several essential lysine residues responsible for the MAC- and MIC-specific nuclear transport, but neither contains any consensus sequence with known monopartite or bipartite NLSs in other model organisms. Our findings contribute to understanding how specific nuclear targeting is achieved to perform distinct nuclear functions in binucleated ciliates.


Assuntos
Transporte Ativo do Núcleo Celular/fisiologia , Sinais de Localização Nuclear/fisiologia , Tetrahymena thermophila/metabolismo , Sequência de Aminoácidos , Animais , Núcleo Celular/metabolismo , Histonas/genética , Histonas/metabolismo , Macronúcleo/fisiologia , Micronúcleo Germinativo/fisiologia , Sinais de Localização Nuclear/genética , Domínios Proteicos/fisiologia , Proteínas de Protozoários/genética , Tetrahymena thermophila/genética
16.
BMC Evol Biol ; 17(1): 220, 2017 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-29041900

RESUMO

BACKGROUND: Interspecies animal hybrids can employ clonal or hemiclonal reproduction modes where one or all parental genomes are transmitted to the progeny without recombination. Nevertheless, some interspecies hybrids retain strong connection with the parental species needed for successful reproduction. Appearance of polyploid hybrid animals may play an important role in the substitution of parental species and in the speciation process. RESULTS: To establish the mechanisms that enable parental species, diploid and polyploid hybrids coexist we have performed artificial crossing experiments of water frogs of Pelophylax esculentus complex. We identified tadpole karyotypes and oocyte genome composition in all females involved in the crossings. The majority of diploid and triploid hybrid frogs produced oocytes with 13 bivalents leading to haploid gametes with the same genome as parental species hybrids usually coexist with. After fertilization of such gametes only diploid animals appeared. Oocytes with 26 bivalents produced by some diploid hybrid frogs lead to diploid gametes, which give rise to triploid hybrids after fertilization. In gonads of all diploid and triploid hybrid tadpoles we found DAPI-positive micronuclei (nucleus-like bodies) involved in selective genome elimination. Hybrid male and female individuals produced tadpoles with variable karyotype and ploidy even in one crossing owing to gametes with various genome composition. CONCLUSIONS: We propose a model of diploid and triploid hybrid frog reproduction in R-E population systems. Triploid Pelophylax esculentus hybrids can transmit genome of parental species they coexist with by producing haploid gametes with the same genome composition. Triploid hybrids cannot produce triploid individuals after crossings with each other and depend on diploid hybrid females producing diploid eggs. In contrast to other population systems, the majority of diploid and triploid hybrid females unexpectedly produced gametes with the same genome as parental species hybrids coexist with.


Assuntos
Hibridização Genética , Rana esculenta/genética , Animais , Cruzamentos Genéticos , Diploide , Feminino , Gametogênese , Genoma , Gônadas/citologia , Haploidia , Masculino , Micronúcleo Germinativo , Oócitos , Rana esculenta/fisiologia , Reprodução , Triploidia
17.
Mutat Res Rev Mutat Res ; 771: 85-98, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28342454

RESUMO

The present review describes available evidence about the fate of micronuclei and micronucleated cells. Micronuclei are small, extranuclear chromatin bodies surrounded by a nuclear envelope. The mechanisms underlying the formation of micronuclei are well understood but not much is known about the potential fate of micronuclei and micronucleated cells. Many studies with different experimental approaches addressed the various aspects of the post-mitotic fate of micronuclei and micronucleated cells. These studies are reviewed here considering four basic possibilities for potential fates of micronuclei: degradation of the micronucleus or the micronucleated cell, reincorporation into the main nucleus, extrusion from the cell, and persistence in the cytoplasm. Two additional fates need to be considered: premature chromosome condensation/chromothripsis and the elimination of micronucleated cells by apoptosis, yielding six potential fates for micronuclei and/or micronucleated cells. The available data is still limited, but it can be concluded that degradation and extrusion of micronuclei might occur in rare cases under specific conditions, reincorporation during the next mitosis occurs more frequently, and the majority of the micronuclei persist without alteration at least until the next mitosis, possibly much longer. Overall, the consequences of micronucleus formation on the cellular level are still far from clear, but they should be investigated further because micronucleus formation may contribute to the initial and later steps of malignant cell transformation, by causing gain or loss of genetic material in the daughter cells and by the possibility of massive chromosome rearrangement in chromosomes entrapped within a micronucleus by the mechanisms of chromothripsis and chromoanagenesis.


Assuntos
Micronúcleo Germinativo , Animais , Linhagem Celular , Humanos
18.
J Radiat Res ; 58(3): 281-291, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-27864506

RESUMO

Several phytoceuticals and extracts of medicinal plants are reported to mitigate deleterious effects of ionizing radiation. The potential of hydro-alcoholic extract of Clerodendron infortunatum (CIE) for providing protection to mice exposed to gamma radiation was investigated. Oral administration of CIE bestowed a survival advantage to mice exposed to lethal doses of gamma radiation. Radiation-induced depletion of the total blood count and bone marrow cellularity were prevented by treatment with CIE. Damage to the cellular DNA (as was evident from the comet assay and the micronucleus index) was also found to be decreased upon CIE administration. Radiation-induced damages to intestinal crypt cells was also reduced by CIE. Studies on gene expression in intestinal cells revealed that there was a marked increase in the Bax/Bcl-2 ratio in mice exposed to whole-body 4 Gy gamma radiation, and that administration of CIE resulted in significant lowering of this ratio, suggestive of reduction of radiation-induced apoptosis. Also, in the intestinal tissue of irradiated animals, following CIE treatment, levels of expression of the DNA repair gene Atm were found to be elevated, and there was reduction in the expression of the inflammatory Cox-2 gene. Thus, our results suggest a beneficial use of Clerodendron infortunatum for mitigating radiation toxicity.


Assuntos
Clerodendrum/química , Raios gama/efeitos adversos , Extratos Vegetais/farmacologia , Irradiação Corporal Total/efeitos adversos , Administração Oral , Animais , Antioxidantes/farmacologia , Compostos de Bifenilo/química , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/efeitos da radiação , Cromatografia Líquida de Alta Pressão , Quebras de DNA de Cadeia Dupla , Sequestradores de Radicais Livres/farmacologia , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/ultraestrutura , Regulação da Expressão Gênica/efeitos dos fármacos , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Camundongos , Micronúcleo Germinativo/metabolismo , Picratos/química , Extratos Vegetais/administração & dosagem , Reticulócitos/efeitos dos fármacos , Reticulócitos/metabolismo , Reticulócitos/efeitos da radiação , Superóxido Dismutase/metabolismo , Análise de Sobrevida , Proteína X Associada a bcl-2/metabolismo
19.
Sci Rep ; 6: 37623, 2016 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-27876887

RESUMO

Concerns on high-energy particle radiation-induced tumorigenic transformation of normal tissue in astronauts, and in cancer patients undergoing radiotherapy, emphasizes the significance of elucidating the mechanisms involved in radiogenic transformation processes. Mostly used genetically modified or tumor-prone models are less reliable in determining human health risk in space or protracted post-treatment normal tissue toxicity. Here, in wild type C57BL/6 mice, we related the deregulation of distinctive set of tissue-specific oncotargets in major organs upon 56Fe (600 MeV/amu; 0.5 Gy/min; 0.8 Gy) particle radiation and compared the response with low LET γ-radiation (137Cs; 0.5 Gy/min; 2 Gy). One of the novel findings is the 'tissue-independent' activation of TAL2 upon high-energy radiation, and thus qualifies TAL2 as a potential biomarker for particle and other qualities of radiation. Heightened expression of TAL2 gene transcript, which sustained over four weeks post-irradiation foster the concept of oncogene addiction signaling in radiogenic transformation. The positive/negative expression of other selected oncotargets that expresses tissue-dependent manner indicated their role as a secondary driving force that addresses the diversity of tissue-dependent characteristics of tumorigenesis. This study, while reporting novel findings on radiogenic transformation of normal tissue when exposed to particle radiation, it also provides a platform for further investigation into different radiation quality, LET and dose/dose rate effect in healthy organs.


Assuntos
Transformação Celular Neoplásica/genética , Vício Oncogênico , Radiação , Animais , Apoptose/efeitos da radiação , Diferenciação Celular/efeitos da radiação , Transformação Celular Neoplásica/patologia , Transformação Celular Neoplásica/efeitos da radiação , Células Epiteliais/metabolismo , Células Epiteliais/efeitos da radiação , Regulação Neoplásica da Expressão Gênica , Marcação In Situ das Extremidades Cortadas , Íons , Queratina-5/metabolismo , Camundongos Endogâmicos C57BL , Micronúcleo Germinativo/metabolismo , Oncogenes , Especificidade de Órgãos/efeitos da radiação , Reação em Cadeia da Polimerase em Tempo Real , Análise Serial de Tecidos , Transcriptoma/genética , Proteína Supressora de Tumor p53/metabolismo
20.
Biomed Pharmacother ; 82: 124-32, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27470347

RESUMO

The purpose of this study was to evaluate the anticancer efficacy of interferon ß in combination with low dose of cisplatin on human cervical cancer progression, as well as its principal action mechanism. The combination treatment synergistically potentiated the effect of interferon ß on cell growth inhibition and DNA damage on HeLa cells by repressing NF-κB/p-Akt signaling. Synergistic targeting of these pathways has a therapeutic potential. Further, the combination treatment ameliorated the expression of pro-apoptotic Bax, and decreased the expression of anti-apoptotic protein Bcl-2. Additionally, the expression of active PARP was significantly increased and MMP-9 level was decreased in combination group as compared to the expression seen for the treatment with interferon ß or cisplatin alone. Results demonstrate that the synergistic inhibitory effects of interferon ß and low dose of cisplatin on human cervical cancer cells and also suggest that the inhibition of NF-κB/p-Akt signaling pathway plays a critical role in the anticancer effects of combination treatment along with the induction of PARP. Therefore, the combination of interferon ß and cisplatin may be a useful treatment for human cervical cancer, with a greater effectiveness than other treatments.


Assuntos
Cisplatino/farmacologia , Interferon beta/farmacologia , NF-kappa B/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Células HeLa , Humanos , Proteínas I-kappa B/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Micronúcleo Germinativo/efeitos dos fármacos , Micronúcleo Germinativo/metabolismo , Fosforilação/efeitos dos fármacos , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Fator de Transcrição STAT2/metabolismo
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