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1.
PLoS One ; 15(9): e0239686, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32997692

RESUMO

INTRODUCTION: A significant proportion of patients with metastatic castration-resistant prostate cancer (mCRPC) harbor mutations in homologous recombination (HR) repair genes, with some of these mutations associating with increased tumor susceptibility to poly(ADP-ribose) polymerase (PARP) inhibitors and platinum-based chemotherapy. While mutations in some HR repair genes (e.g., BRCA1/2) have been associated with a more aggressive clinical course, prior studies correlating HR mutational status with treatment response to androgen receptor (AR) signaling inhibitors (ARSIs) or taxane-based chemotherapy have yielded conflicting results. METHODS: We conducted a single-center retrospective analysis to assess clinical outcomes to conventional, regulatory-approved therapies in mCRPC patients with somatic (monoallelic and biallelic) and/or germline HR repair mutations compared to patients without alterations as determined by clinical-grade next-generation sequencing assays. The primary endpoint was PSA30/PSA50 response, defined as ≥30%/≥50% prostate-specific antigen (PSA) reduction from baseline. Secondary endpoints of PSA progression-free survival (pPFS) and clinical/radiographic progression-free survival (crPFS) were estimated using Kaplan-Meier methods. RESULTS: A total of 90 consecutively selected patients were included in this analysis, of which 33 (37%) were identified to have HR repair gene mutations. Age, race, Gleason score, prior surgery, and receipt of prior radiation therapy were comparable between carriers and non-carriers. There was no evidence that PSA30/PSA50 differed by HR gene mutational status. Median pPFS and crPFS ranged 3-14 months across treatment modalities, but there was no evidence either differed by HR gene mutational status (all p>0.05). There was also no difference in outcomes between those with BRCA2 or PALB2 mutations (n = 17) compared to those without HR repair mutations. CONCLUSION: HR gene mutational status was associated with comparable clinical outcomes following treatment with ARSIs or taxane-based chemotherapy. Additional prospective studies are needed to confirm these findings.


Assuntos
Mutação , Neoplasias de Próstata Resistentes à Castração/genética , Reparo de DNA por Recombinação/genética , Idoso , Antineoplásicos/uso terapêutico , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteína BRCA2/genética , Quinases Ciclina-Dependentes/genética , Resistencia a Medicamentos Antineoplásicos , Proteína do Grupo de Complementação N da Anemia de Fanconi/genética , Humanos , Proteína Homóloga a MRE11/genética , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Intervalo Livre de Progressão , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/patologia , Inibidores da Síntese de Esteroides/uso terapêutico
2.
Nat Commun ; 11(1): 4828, 2020 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973141

RESUMO

ATR responds to mechanical stress at the nuclear envelope and mediates envelope-associated repair of aberrant topological DNA states. By combining microscopy, electron microscopic analysis, biophysical and in vivo models, we report that ATR-defective cells exhibit altered nuclear plasticity and YAP delocalization. When subjected to mechanical stress or undergoing interstitial migration, ATR-defective nuclei collapse accumulating nuclear envelope ruptures and perinuclear cGAS, which indicate loss of nuclear envelope integrity, and aberrant perinuclear chromatin status. ATR-defective cells also are defective in neuronal migration during development and in metastatic dissemination from circulating tumor cells. Our findings indicate that ATR ensures mechanical coupling of the cytoskeleton to the nuclear envelope and accompanying regulation of envelope-chromosome association. Thus the repertoire of ATR-regulated biological processes extends well beyond its canonical role in triggering biochemical implementation of the DNA damage response.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Núcleo Celular/metabolismo , Estresse Mecânico , Citoesqueleto de Actina , Animais , Proteínas Mutadas de Ataxia Telangiectasia/genética , Encéfalo , Cromatina , Citoplasma , Citoesqueleto/metabolismo , Dano ao DNA , Camundongos Knockout , Metástase Neoplásica , Neurogênese , Membrana Nuclear/metabolismo
3.
Nucleic Acids Res ; 48(17): 9710-9723, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32890395

RESUMO

Two DNA repair pathways operate at DNA double strand breaks (DSBs): non-homologous end-joining (NHEJ), that requires two adjacent DNA ends for ligation, and homologous recombination (HR), that resects one DNA strand for invasion of a homologous duplex. Faithful repair of replicative single-ended DSBs (seDSBs) is mediated by HR, due to the lack of a second DNA end for end-joining. ATM stimulates resection at such breaks through multiple mechanisms including CtIP phosphorylation, which also promotes removal of the DNA-ends sensor and NHEJ protein Ku. Here, using a new method for imaging the recruitment of the Ku partner DNA-PKcs at DSBs, we uncover an unanticipated role of ATM in removing DNA-PKcs from seDSBs in human cells. Phosphorylation of DNA-PKcs on the ABCDE cluster is necessary not only for DNA-PKcs clearance but also for the subsequent MRE11/CtIP-dependent release of Ku from these breaks. We propose that at seDSBs, ATM activity is necessary for the release of both Ku and DNA-PKcs components of the NHEJ apparatus, and thereby prevents subsequent aberrant interactions between seDSBs accompanied by DNA-PKcs autophosphorylation and detrimental commitment to Lig4-dependent end-joining.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades/fisiologia , Proteína Quinase Ativada por DNA/metabolismo , Autoantígeno Ku/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/genética , Camptotecina/farmacologia , Linhagem Celular , Reparo do DNA por Junção de Extremidades/efeitos dos fármacos , DNA Ligase Dependente de ATP/genética , DNA Ligase Dependente de ATP/metabolismo , DNA de Cadeia Simples , Proteína Quinase Ativada por DNA/genética , Humanos , Autoantígeno Ku/genética , Proteína Homóloga a MRE11/genética , Proteína Homóloga a MRE11/metabolismo , Fosforilação , Inibidores da Topoisomerase I/farmacologia
4.
Nat Commun ; 11(1): 4077, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32796846

RESUMO

Double-strand breaks (DSBs) are the most toxic type of DNA lesions. Cells repair these lesions using either end protection- or end resection-coupled mechanisms. To study DSB repair choice, we present the Color Assay Tracing-Repair (CAT-R) to simultaneously quantify DSB repair via end protection and end resection pathways. CAT-R introduces DSBs using CRISPR/Cas9 in a tandem fluorescent reporter, whose repair distinguishes small insertions/deletions from large deletions. We demonstrate CAT-R applications in chemical and genetic screens. First, we evaluate 21 compounds currently in clinical trials which target the DNA damage response. Second, we examine how 417 factors involved in DNA damage response influence the choice between end protection and end resection. Finally, we show that impairing nucleotide excision repair favors error-free repair, providing an alternative way for improving CRISPR/Cas9-based knock-ins. CAT-R is a high-throughput, versatile assay to assess DSB repair choice, which facilitates comprehensive studies of DNA repair and drug efficiency testing.


Assuntos
Sistemas CRISPR-Cas , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Proteínas Mutadas de Ataxia Telangiectasia/genética , Ciclo Celular , Sobrevivência Celular , Dano ao DNA , Reparo do DNA por Junção de Extremidades , Avaliação Pré-Clínica de Medicamentos , Técnicas de Inativação de Genes , Células HEK293 , Humanos , Poli(ADP-Ribose) Polimerase-1/genética
5.
PLoS One ; 15(8): e0237669, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32810137

RESUMO

Pancreatic beta cell death is a hallmark of type 1 and 2 diabetes (T1D/T2D), but the underlying molecular mechanisms are incompletely understood. Key proteins of the DNA damage response (DDR), including tumor protein P53 (P53, also known as TP53 or TRP53 in rodents) and Ataxia Telangiectasia Mutated (ATM), a kinase known to act upstream of P53, have been associated with T2D. Here we test and compare the effect of ATM and P53 ablation on beta cell survival in the rat beta cell line Ins1E. We demonstrate that ATM and P53 differentially regulate beta cell apoptosis induced upon fundamentally different types of diabetogenic beta cell stress, including DNA damage, inflammation, lipotoxicity and endoplasmic reticulum (ER) stress. DNA damage induced apoptosis by treatment with the commonly used diabetogenic agent streptozotocin (STZ) is regulated by both ATM and P53. We show that ATM is a key STZ induced activator of P53 and that amelioration of STZ induced cell death by inhibition of ATM mainly depends on P53. While both P53 and ATM control lipotoxic beta cell apoptosis, ATM but not P53 fails to alter inflammatory beta cell death. In contrast, tunicamycin induced (ER stress associated) apoptosis is further increased by ATM knockdown or inhibition, but not by P53 knockdown. Our results reveal differential roles for P53 and ATM in beta cell survival in vitro in the context of four key pathophysiological types of diabetogenic beta cell stress, and indicate that ATM can use P53 independent signaling pathways to modify beta cell survival, dependent on the cellular insult.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Sobrevivência Celular/genética , Células Secretoras de Insulina/patologia , Transdução de Sinais/genética , Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/genética , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Diabetes Mellitus/patologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/genética , Técnicas de Silenciamento de Genes , Humanos , Células Secretoras de Insulina/efeitos dos fármacos , Inibidores de Proteases/farmacologia , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , RNA Interferente Pequeno/metabolismo , Ratos , Estreptozocina/toxicidade , Tunicamicina/toxicidade
6.
Nat Commun ; 11(1): 4154, 2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32814778

RESUMO

The DNA damage response (DDR) coordinates DNA metabolism with nuclear and non-nuclear processes. The DDR kinase Rad53CHK1/CHK2 controls histone degradation to assist DNA repair. However, Rad53 deficiency causes histone-dependent growth defects in the absence of DNA damage, pointing out unknown physiological functions of the Rad53-histone axis. Here we show that histone dosage control by Rad53 ensures metabolic homeostasis. Under physiological conditions, Rad53 regulates histone levels through inhibitory phosphorylation of the transcription factor Spt21NPAT on Ser276. Rad53-Spt21 mutants display severe glucose dependence, caused by excess histones through two separable mechanisms: dampening of acetyl-coenzyme A-dependent carbon metabolism through histone hyper-acetylation, and Sirtuin-mediated silencing of starvation-induced subtelomeric domains. We further demonstrate that repression of subtelomere silencing by physiological Tel1ATM and Rpd3HDAC activities coveys tolerance to glucose restriction. Our findings identify DDR mutations, histone imbalances and aberrant subtelomeric chromatin as interconnected causes of glucose dependence, implying that DDR kinases coordinate metabolism and epigenetic changes.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Quinase do Ponto de Checagem 2/metabolismo , Glucose/metabolismo , Histonas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo , Acetilação , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas de Ciclo Celular/genética , Quinase do Ponto de Checagem 2/genética , Dano ao DNA , Reparo do DNA , Inativação Gênica , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Mutação , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Serina/genética , Serina/metabolismo , Telômero/genética , Fatores de Transcrição/genética
7.
Nucleic Acids Res ; 48(16): 9109-9123, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32729622

RESUMO

Nuclear factor erythroid 2-related factor 2 (NRF2) is a well-characterized transcription factor that protects cells against oxidative and electrophilic stresses. Emerging evidence has suggested that NRF2 protects cells against DNA damage by mechanisms other than antioxidation, yet the mechanism remains poorly understood. Here, we demonstrate that knockout of NRF2 in cells results in hypersensitivity to ionizing radiation (IR) in the presence or absence of reactive oxygen species (ROS). Under ROS scavenging conditions, induction of DNA double-strand breaks (DSBs) increases the NRF2 protein level and recruits NRF2 to DNA damage sites where it interacts with ATR, resulting in activation of the ATR-CHK1-CDC2 signaling pathway. In turn, this leads to G2 cell cycle arrest and the promotion of homologous recombination repair of DSBs, thereby preserving genome stability. The inhibition of NRF2 by brusatol increased the radiosensitivity of tumor cells in xenografts by perturbing ATR and CHK1 activation. Collectively, our results reveal a novel function of NRF2 as an ATR activator in the regulation of the cellular response to DSBs. This shift in perspective should help furnish a more complete understanding of the function of NRF2 and the DNA damage response.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Fator 2 Relacionado a NF-E2/genética , Reparo de DNA por Recombinação/genética , Células A549 , Animais , Proteína Quinase CDC2/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Quinase 1 do Ponto de Checagem/genética , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Quebras de DNA de Cadeia Dupla/efeitos da radiação , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/efeitos da radiação , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Técnicas de Inativação de Genes , Xenoenxertos , Humanos , Camundongos , Quassinas/farmacologia , Tolerância a Radiação/efeitos dos fármacos , Radiação Ionizante , Reparo de DNA por Recombinação/efeitos dos fármacos , Reparo de DNA por Recombinação/efeitos da radiação , Transdução de Sinais/efeitos dos fármacos
8.
Mol Cell ; 79(3): 425-442.e7, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32615088

RESUMO

Double-strand breaks (DSBs) are the most deleterious DNA lesions, which, if left unrepaired, may lead to genome instability or cell death. Here, we report that, in response to DSBs, the RNA methyltransferase METTL3 is activated by ATM-mediated phosphorylation at S43. Phosphorylated METTL3 is then localized to DNA damage sites, where it methylates the N6 position of adenosine (m6A) in DNA damage-associated RNAs, which recruits the m6A reader protein YTHDC1 for protection. In this way, the METTL3-m6A-YTHDC1 axis modulates accumulation of DNA-RNA hybrids at DSBs sites, which then recruit RAD51 and BRCA1 for homologous recombination (HR)-mediated repair. METTL3-deficient cells display defective HR, accumulation of unrepaired DSBs, and genome instability. Accordingly, depletion of METTL3 significantly enhances the sensitivity of cancer cells and murine xenografts to DNA damage-based therapy. These findings uncover the function of METTL3 and YTHDC1 in HR-mediated DSB repair, which may have implications for cancer therapy.


Assuntos
Adenosina/análogos & derivados , Neoplasias de Cabeça e Pescoço/genética , Metiltransferases/genética , Proteínas do Tecido Nervoso/genética , Fatores de Processamento de RNA/genética , Reparo de DNA por Recombinação/efeitos dos fármacos , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Adenosina/metabolismo , Animais , Antibióticos Antineoplásicos/farmacologia , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Bleomicina/farmacologia , Linhagem Celular Tumoral , DNA/genética , DNA/metabolismo , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Células HEK293 , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Metiltransferases/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteínas do Tecido Nervoso/metabolismo , Hibridização de Ácido Nucleico , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteoblastos/patologia , Fosforilação , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Fatores de Processamento de RNA/metabolismo , Rad51 Recombinase/genética , Rad51 Recombinase/metabolismo , Ribonuclease H/genética , Ribonuclease H/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Carcinoma de Células Escamosas de Cabeça e Pescoço/mortalidade , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Análise de Sobrevida , Ensaios Antitumorais Modelo de Xenoenxerto
9.
PLoS Pathog ; 16(6): e1008514, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32479542

RESUMO

Deoxyribonucleic acid (DNA) damage response (DDR) is the fundamental cellular response for maintaining genomic integrity and suppressing tumorigenesis. The activation of ataxia telangiectasia-mutated (ATM) kinase is central to DNA double-strand break (DSB) for maintaining host-genome integrity in mammalian cells. Oncolytic Newcastle disease virus (NDV) can selectively replicate in tumor cells; however, its influence on the genome integrity of tumor cells is not well-elucidated. Here, we found that membrane fusion and NDV infection triggered DSBs in tumor cells. The late replication and membrane fusion of NDV mechanistically activated the ATM-mediated DSB pathway via the ATM-Chk2 axis, as evidenced by the hallmarks of DSBs, i.e., auto-phosphorylated ATM and phosphorylated H2AX and Chk2. Immunofluorescence data showed that multifaceted ATM-controlled phosphorylation markedly induced the formation of pan-nuclear punctum foci in response to NDV infection and F-HN co-expression. Specific drug-inhibitory experiments on ATM kinase activity further suggested that ATM-mediated DSBs facilitated NDV replication and membrane fusion. We confirmed that the Mre11-RAD50-NBS1 (MRN) complex sensed the DSB signal activation triggered by NDV infection and membrane fusion. The pharmacological inhibition of MRN activity also significantly inhibited intracellular and extracellular NDV replication and syncytia formation. Collectively, these data identified for the first time a direct link between the membrane fusion induced by virus infection and DDR pathways, thereby providing new insights into the efficient replication of oncolytic NDV in tumor cells.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Quebras de DNA de Cadeia Dupla , Células Gigantes , Proteínas de Neoplasias/metabolismo , Neoplasias/metabolismo , Vírus da Doença de Newcastle/fisiologia , Vírus Oncolíticos/fisiologia , Replicação Viral , Células A549 , Hidrolases Anidrido Ácido/genética , Hidrolases Anidrido Ácido/metabolismo , Animais , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Embrião de Galinha , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Células Gigantes/metabolismo , Células Gigantes/virologia , Células HEK293 , Humanos , Proteína Homóloga a MRE11/genética , Proteína Homóloga a MRE11/metabolismo , Proteínas de Neoplasias/genética , Neoplasias/genética , Neoplasias/virologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Transdução de Sinais/genética
10.
Nucleic Acids Res ; 48(13): 7252-7264, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32542389

RESUMO

The DNA damage response is essential to maintain genomic stability, suppress replication stress, and protect against carcinogenesis. The ATR-CHK1 pathway is an essential component of this response, which regulates cell cycle progression in the face of replication stress. PARP14 is an ADP-ribosyltransferase with multiple roles in transcription, signaling, and DNA repair. To understand the biological functions of PARP14, we catalogued the genetic components that impact cellular viability upon loss of PARP14 by performing an unbiased, comprehensive, genome-wide CRISPR knockout genetic screen in PARP14-deficient cells. We uncovered the ATR-CHK1 pathway as essential for viability of PARP14-deficient cells, and identified regulation of DNA replication dynamics as an important mechanistic contributor to the synthetic lethality observed. Our work shows that PARP14 is an important modulator of the response to ATR-CHK1 pathway inhibitors.


Assuntos
Replicação do DNA , Poli(ADP-Ribose) Polimerases/metabolismo , Mutações Sintéticas Letais , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem/genética , Quinase 1 do Ponto de Checagem/metabolismo , Humanos , Poli(ADP-Ribose) Polimerases/genética
11.
Oncology ; 98(8): 575-582, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32408300

RESUMO

BACKGROUND: Identification of high-risk stage II colorectal cancer (CRC) patients, potential candidates for adjuvant chemotherapy, is challenging. Current clinical guidelines rely mainly on histopathological markers with relatively weak prognostic value. This motivates further search for prognostic markers. METHODS: This explorative study aimed to identify potential candidate gene mutations to facilitate differentiation between subgroups of patients with CRC stage II. Panel-based massive parallel sequencing was used to genetically characterize tumor tissues from 85 patients radically operated for CRC stage II, of which 12 developed recurrent cancer during follow-up. Genetic data was compared between patients with or without cancer recurrence, between tumors located in colon and in rectum, and for association with tumor differentiation grade. RESULTS: Genetic variation in ATM, C11ORF65 was associated with recurrence-free survival. Previous reports regarding the association between BRAF mutation and a higher age at diagnosis, and tumor location in colon were confirmed. APC, BRAF, or KRAS mutation was associated with tumor differentiation grade. Multiple correspondence analyses revealed no obvious clustering of patients with the studied clinical characteristics, indicating that the genetic signatures observed here were unique for each individual. CONCLUSIONS: Taken together, we have demonstrated the utility of panel-based massive parallel sequencing to explore the pathogenesis of CRC stage II. We have identified promising candidate gene mutations associated with cancer recurrence, tumor location, and differentiation grade in patients with CRC stage II, which merit further investigation.


Assuntos
Proteína da Polipose Adenomatosa do Colo/genética , Proteínas Mutadas de Ataxia Telangiectasia/genética , Neoplasias Colorretais/genética , Genoma Humano/genética , Mutação , Recidiva Local de Neoplasia/genética , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais/patologia , Feminino , Seguimentos , Variação Genética , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos
12.
PLoS One ; 15(5): e0227786, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32433703

RESUMO

Homeostasis is an essential concept to understand the stability of organisms and their adaptive behaviors when coping with external and internal assaults. Many hormones that take part in homeostatic control come in antagonistic pairs, such as glucagon and insulin reflecting the inflow and outflow compensatory mechanisms to control a certain internal variable, such as blood sugar levels. By including negative feedback loops homeostatic controllers can exhibit oscillations with characteristic frequencies. In this paper we demonstrate the associated frequency changes in homeostatic systems when individual controllers -in a set of interlocked feedback loops- gain control in response to environmental changes. Taking p53 as an example, we show how Per2, ATM and Mdm2 feedback loops -interlocked with p53- gain individual control in dependence to the level of DNA damage, and how each of these controllers provide certain functionalities in their regulation of p53. In unstressed cells, the circadian regulator Per2 ensures a basic p53 level to allow its rapid up-regulation in case of DNA damage. When DNA damage occurs the ATM controller increases the level of p53 and defends it towards uncontrolled degradation, which despite DNA damage, would drive p53 to lower values and p53 dysfunction. Mdm2 on its side keeps p53 at a high but sub-apoptotic level to avoid premature apoptosis. However, with on-going DNA damage the Mdm2 set-point is increased by HSP90 and other p53 stabilizers leading finally to apoptosis. An emergent aspect of p53 upregulation during cell stress is the coordinated inhibition of ubiquitin-independent and ubiquitin-dependent degradation reactions. Whether oscillations serve a function or are merely a by-product of the controllers are discussed in view of the finding that homeostatic control of p53, as indicated above, does in principle not require oscillatory homeostats.


Assuntos
Retroalimentação Fisiológica , Homeostase/genética , Modelos Teóricos , Proteína Supressora de Tumor p53/genética , Apoptose/genética , Proteínas Mutadas de Ataxia Telangiectasia/genética , Ritmo Circadiano/genética , Dano ao DNA/genética , Regulação da Expressão Gênica/genética , Humanos , Proteínas Circadianas Period/genética , Fosforilação/genética , Proteínas Proto-Oncogênicas c-mdm2/genética , Ubiquitina/genética
13.
Mol Cell ; 78(4): 714-724.e5, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32353258

RESUMO

Nonrandom DNA segregation (NDS) is a mitotic event in which sister chromatids carrying the oldest DNA strands are inherited exclusively by one of the two daughter cells. Although this phenomenon has been observed across various organisms, the mechanism and physiological relevance of this event remain poorly defined. Here, we demonstrate that DNA replication stress can trigger NDS in human cells. This biased inheritance of old template DNA is associated with the asymmetric DNA damage response (DDR), which derives at least in part from telomeric DNA. Mechanistically, we reveal that the ATR/CHK1 signaling pathway plays an essential role in mediating NDS. We show that this biased segregation process leads to cell-cycle arrest and cell death in damaged daughter cells inheriting newly replicated DNA. These data therefore identify a key role for NDS in the maintenance of genomic integrity within cancer cell populations undergoing replication stress due to oncogene activation.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Quinase 1 do Ponto de Checagem/metabolismo , Cromossomos Humanos/genética , Dano ao DNA , Replicação do DNA , Mitose , Proteínas Mutadas de Ataxia Telangiectasia/genética , Quinase 1 do Ponto de Checagem/genética , Segregação de Cromossomos , Células HeLa , Humanos , Transdução de Sinais
14.
Nat Commun ; 11(1): 2220, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393777

RESUMO

Few germline mutations are known to affect lung cancer risk. We performed analyses of rare variants from 39,146 individuals of European ancestry and investigated gene expression levels in 7,773 samples. We find a large-effect association with an ATM L2307F (rs56009889) mutation in adenocarcinoma for discovery (adjusted Odds Ratio = 8.82, P = 1.18 × 10-15) and replication (adjusted OR = 2.93, P = 2.22 × 10-3) that is more pronounced in females (adjusted OR = 6.81 and 3.19 and for discovery and replication). We observe an excess loss of heterozygosity in lung tumors among ATM L2307F allele carriers. L2307F is more frequent (4%) among Ashkenazi Jewish populations. We also observe an association in discovery (adjusted OR = 2.61, P = 7.98 × 10-22) and replication datasets (adjusted OR = 1.55, P = 0.06) with a loss-of-function mutation, Q4X (rs150665432) of an uncharacterized gene, KIAA0930. Our findings implicate germline genetic variants in ATM with lung cancer susceptibility and suggest KIAA0930 as a novel candidate gene for lung cancer risk.


Assuntos
Adenocarcinoma/genética , Proteínas Mutadas de Ataxia Telangiectasia/genética , Neoplasias Pulmonares/genética , Idoso , Alelos , Bases de Dados Genéticas , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Predisposição Genética para Doença , Técnicas de Genotipagem , Mutação em Linhagem Germinativa , Heterozigoto , Humanos , Judeus/genética , Masculino , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Razão de Chances , Análise de Sequência com Séries de Oligonucleotídeos , Linhagem , RNA-Seq , Fatores de Risco
16.
N Engl J Med ; 382(22): 2091-2102, 2020 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-32343890

RESUMO

BACKGROUND: Multiple loss-of-function alterations in genes that are involved in DNA repair, including homologous recombination repair, are associated with response to poly(adenosine diphosphate-ribose) polymerase (PARP) inhibition in patients with prostate and other cancers. METHODS: We conducted a randomized, open-label, phase 3 trial evaluating the PARP inhibitor olaparib in men with metastatic castration-resistant prostate cancer who had disease progression while receiving a new hormonal agent (e.g., enzalutamide or abiraterone). All the men had a qualifying alteration in prespecified genes with a direct or indirect role in homologous recombination repair. Cohort A (245 patients) had at least one alteration in BRCA1, BRCA2, or ATM; cohort B (142 patients) had alterations in any of 12 other prespecified genes, prospectively and centrally determined from tumor tissue. Patients were randomly assigned (in a 2:1 ratio) to receive olaparib or the physician's choice of enzalutamide or abiraterone (control). The primary end point was imaging-based progression-free survival in cohort A according to blinded independent central review. RESULTS: In cohort A, imaging-based progression-free survival was significantly longer in the olaparib group than in the control group (median, 7.4 months vs. 3.6 months; hazard ratio for progression or death, 0.34; 95% confidence interval, 0.25 to 0.47; P<0.001); a significant benefit was also observed with respect to the confirmed objective response rate and the time to pain progression. The median overall survival in cohort A was 18.5 months in the olaparib group and 15.1 months in the control group; 81% of the patients in the control group who had progression crossed over to receive olaparib. A significant benefit for olaparib was also seen for imaging-based progression-free survival in the overall population (cohorts A and B). Anemia and nausea were the main toxic effects in patients who received olaparib. CONCLUSIONS: In men with metastatic castration-resistant prostate cancer who had disease progression while receiving enzalutamide or abiraterone and who had alterations in genes with a role in homologous recombination repair, olaparib was associated with longer progression-free survival and better measures of response and patient-reported end points than either enzalutamide or abiraterone. (Funded by AstraZeneca and Merck Sharp & Dohme; PROfound ClinicalTrials.gov number, NCT02987543.).


Assuntos
Antineoplásicos/uso terapêutico , Mutação com Perda de Função , Ftalazinas/uso terapêutico , Piperazinas/uso terapêutico , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Androstenos/efeitos adversos , Androstenos/uso terapêutico , Antineoplásicos/efeitos adversos , Proteínas Mutadas de Ataxia Telangiectasia/genética , Genes BRCA1 , Genes BRCA2 , Humanos , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica/tratamento farmacológico , Feniltioidantoína/efeitos adversos , Feniltioidantoína/análogos & derivados , Feniltioidantoína/uso terapêutico , Ftalazinas/efeitos adversos , Piperazinas/efeitos adversos , Inibidores de Poli(ADP-Ribose) Polimerases/efeitos adversos , Intervalo Livre de Progressão , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/mortalidade , Neoplasias de Próstata Resistentes à Castração/patologia
17.
J Integr Neurosci ; 19(1): 125-129, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32259893

RESUMO

Autosomal recessive cerebellar ataxias comprise many types of diseases. The most frequent autosomal recessive cerebellar ataxias are Friedreich ataxia, but other types are relatively rare. We encountered a consanguineous family with two cases of late-onset cerebellar ataxia with neuropathy. We performed whole-exome sequencing in one patient and confirmed by Sanger sequencing in other family members. Neurological examination revealed cerebellar ataxia, hand tremor, and neck dystonia, distal muscle wasting, and diminished tendon reflexes. The patients had no conjunctival telangiectasia or immunodeficiency. Blood examination revealed slightly elevated α-fetoprotein. Brain MRI demonstrated marked cerebellar atrophy and mild brainstem atrophy. The electrophysiologic study and nerve biopsy showed axonal neuropathy. Whole-exome sequencing revealed a novel homozygous missense variant (NM_000051.3: c.496G > C) in the ataxia-telangiectasia mutated gene. This homozygous variant was found in another patient, co-segregated within the family members-this variant results in aberrant splicing (skipping exon 5) on RT-PCR analysis. We identified the ataxia-telangiectasia mutated variant in an adult, late-onset autosomal recessive cerebellar ataxias family. We should consider ataxia-telangiectasia even in late-onset autosomal recessive cerebellar ataxias without telangiectasia or immunodeficiency.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Degenerações Espinocerebelares/genética , Degenerações Espinocerebelares/patologia , Adulto , Axônios/patologia , Encéfalo/patologia , Feminino , Humanos , Masculino , Mutação , Linhagem , Degenerações Espinocerebelares/fisiopatologia , Sequenciamento Completo do Exoma
18.
Laryngoscope ; 130(8): 1954-1960, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32275333

RESUMO

OBJECTIVES: Most early stage laryngeal squamous cell carcinomas (LSCC) are treated with radiotherapy. Discovery of new biomarkers are needed to improve prediction of outcome after radiotherapy and to identify potential targets for systemic targeted therapy. The ataxia telangiectasia mutated (ATM) gene plays a critical role in DNA damage response induced by ionizing radiation. METHODS: The prognostic value of immunohistochemical expression of pATM, pChk2, and p53 were investigated in 141 patients with T1-T2 LSCC curatively treated with external beam radiotherapy. Uni- and multivariable Cox regression analyses were performed to examine the relation between expression levels of markers and local control. RESULTS: Local control was significantly worse in cases with high levels of pATM (HR 2.14; 95% CI, 1.08-4.24; P = .03). No significant associations with local control were found for pChk2 and p53 expression. The association of high pATM expression with poor local control was only found for supraglottic LSCC (HR 10.9; 95% CI, 1.40-84.4; P = .02). CONCLUSION: Our findings suggest a potential role for ATM in response to radiotherapy in early stage supraglottic LSCC and imply ATM inhibition as a possibility to improve response to radiotherapy. LEVEL OF EVIDENCE: NA Laryngoscope, 130: 1954-1960, 2020.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Biomarcadores Tumorais/genética , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/radioterapia , Neoplasias Laríngeas/patologia , Neoplasias Laríngeas/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Quinase do Ponto de Checagem 2/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Proteína Supressora de Tumor p53/genética
19.
Gene ; 741: 144578, 2020 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-32171823

RESUMO

The ataxia telangiectasia mutated (ATM) gene is involved in repairing DNA lesions and maintaining genome stability, which is related to cancer invasion and metastasis. This gene influences the risk of cancers. Many studies have demonstrated that the ATM rs189037 G>A polymorphism is linked with the risks of different types of cancer. However, no study has probed the relationship between the ATM rs189037 G>A polymorphism and gastric cancer (GC) risk. Therefore, the aims of this study were to investigate the association of the ATM rs189037 G>A polymorphism with the risk and prognosis of GC in a case-control investigation of 345 GC patients and 467 controls in China. The rs189037 G>A polymorphism was genotyped using polymerase chain reaction-restriction fragment length polymorphism. This polymorphism was related to a significantly higher risk of GC [AA vs. GG: OR (95% CI): 1.80 (1.20-2.70), P = 0.04; GG vs. AA + GA: 1.46 (1.08-1.98); A vs. G: 1.34 (1.10-1.64), P = 0.004]. Subgroup analyses showed significant associations with female gender, smoking, alcohol consumption, age ≥60 years, and positive Helicobacter pylori status. This polymorphism was also correlated with TNM stage III + IV and tumor size >4 cm. GC patients carrying the AA genotype of the rs189037 polymorphism also had lower overall survival. In conclusion, the ATM rs189037 G>A polymorphism was related to increased susceptibility to and poorer prognosis in GC in this Chinese population.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Neoplasias Gástricas/genética , Adulto , Idoso , China/epidemiologia , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Fatores de Risco , Neoplasias Gástricas/patologia
20.
Nucleic Acids Res ; 48(7): 3678-3691, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32123907

RESUMO

Genomic instability resulting from defective DNA damage responses or repair causes several abnormalities, including progressive cerebellar ataxia, for which the molecular mechanisms are not well understood. Here, we report a new murine model of cerebellar ataxia resulting from concomitant inactivation of POLB and ATM. POLB is one of key enzymes for the repair of damaged or chemically modified bases, including methylated cytosine, but selective inactivation of Polb during neurogenesis affects only a subpopulation of cortical interneurons despite the accumulation of DNA damage throughout the brain. However, dual inactivation of Polb and Atm resulted in ataxia without significant neuropathological defects in the cerebellum. ATM is a protein kinase that responds to DNA strand breaks, and mutations in ATM are responsible for Ataxia Telangiectasia, which is characterized by progressive cerebellar ataxia. In the cerebella of mice deficient for both Polb and Atm, the most downregulated gene was Itpr1, likely because of misregulated DNA methylation cycle. ITPR1 is known to mediate calcium homeostasis, and ITPR1 mutations result in genetic diseases with cerebellar ataxia. Our data suggest that dysregulation of ITPR1 in the cerebellum could be one of contributing factors to progressive ataxia observed in human genomic instability syndromes.


Assuntos
Ataxia Cerebelar/genética , Cerebelo/metabolismo , Metilação de DNA , DNA Polimerase beta/genética , Receptores de Inositol 1,4,5-Trifosfato/genética , Animais , Proteínas Mutadas de Ataxia Telangiectasia/genética , Encéfalo/embriologia , Encéfalo/patologia , Cerebelo/anormalidades , Cerebelo/patologia , Citosina/metabolismo , Dano ao DNA , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Camundongos , Camundongos Knockout , Neurogênese/genética
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