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1.
Lasers Med Sci ; 39(1): 56, 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38329547

RESUMO

Photobiomodulation (PBM) induced by non-ionizing radiations emitted from low-power lasers and light-emitting diodes (LEDs) has been used for various therapeutic purposes due to its molecular, cellular, and systemic effects. At the molecular level, experimental data have suggested that PBM modulates base excision repair (BER), which is responsible for restoring DNA damage. There is a relationship between the misfunction of the BER DNA repair pathway and the development of tumors, including breast cancer. However, the effects of PBM on cancer cells have been controversial. Breast cancer (BC) is the main public health problem in the world and is the most diagnosed type of cancer among women worldwide. Therefore, the evaluation of new strategies, such as PBM, could increase knowledge about BC and improve therapies against BC. Thus, this work aims to evaluate the effects of low-power red laser (658 nm) and blue LED (470 nm) on the mRNA levels from BER genes in human breast cancer cells. MCF-7 and MDA-MB-231 cells were irradiated with a low-power red laser (69 J cm-2, 0.77 W cm-2) and blue LED (482 J cm-2, 5.35 W cm-2), alone or in combination, and the relative mRNA levels of the APTX, PolB, and PCNA genes were assessed by reverse transcription-quantitative polymerase chain reaction. The results suggested that exposure to low-power red laser and blue LED decreased the mRNA levels from APTX, PolB, and PCNA genes in human breast cancer cells. Our research shows that photobiomodulation induced by low-power red laser and blue LED decreases the mRNA levels of repair genes from the base excision repair pathway in MCF-7 and MDA-MB-231 cells.


Assuntos
Neoplasias da Mama , Terapia com Luz de Baixa Intensidade , Humanos , Feminino , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/radioterapia , Antígeno Nuclear de Célula em Proliferação/metabolismo , Lasers , Reparo do DNA/genética , Terapia com Luz de Baixa Intensidade/métodos
2.
Int J Mol Sci ; 24(10)2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37240218

RESUMO

DNA repair pathways are essential for maintaining genome stability, and understanding the regulation of these mechanisms may help in the design of new strategies for treatments, the prevention of platinum-based chemoresistance, and the prolongation of overall patient survival not only with respect to ovarian cancer. The role of hyperthermic intraperitoneal chemotherapy (HIPEC) together with cytoreductive surgery (CRS) and adjuvant systemic chemotherapy is receiving more interest in ovarian cancer (OC) treatment because of the typical peritoneal spread of the disease. The aim of our study was to compare the expression level of 84 genes involved in the DNA repair pathway in tumors and the paired peritoneal metastasis tissue of patients treated with CRS/platinum-based HIPEC with respect to overall patient survival, presence of peritoneal carcinomatosis, treatment response, and alterations in the BRCA1 and BRCA2 genes. Tumors and metastatic tissue from 28 ovarian cancer patients collected during cytoreductive surgery before HIPEC with cisplatin were used for RNA isolation and subsequent cDNA synthesis. Quantitative real-time PCR followed. The most interesting findings of our study are undoubtedly the gene interactions among the genes CCNH, XPA, SLK, RAD51C, XPA, NEIL1, and ATR for primary tumor tissue and ATM, ATR, BRCA2, CDK7, MSH2, MUTYH, POLB, and XRCC4 for metastases. Another interesting finding is the correlation between gene expression and overall survival (OS), where a low expression correlates with a worse OS.


Assuntos
DNA Glicosilases , Hipertermia Induzida , Neoplasias Ovarianas , Humanos , Feminino , Quimioterapia Intraperitoneal Hipertérmica , Intervalo Livre de Doença , Hipertermia Induzida/métodos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Reparo do DNA/genética , Terapia Combinada , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Taxa de Sobrevida , Estudos Retrospectivos , DNA Glicosilases/genética
3.
Mutat Res Rev Mutat Res ; 790: 108427, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35688302

RESUMO

Combinations of genetic and environmental factors are responsible for the development of many human diseases, such as cancer, as demonstrated using various biomarkers. Within this scenario, DNA repair holds a gate-keeper position which determines outcomes after appearance of DNA damage and, therefore, adverse cellular consequences, e.g., initiation of carcinogenesis. DNA repair deficiency and some of the subsequent events can be validated from studies using live cells from cancer patients. However, these deficiencies/events are difficult to demonstrate in live cells from normal individuals because individual variations in DNA repair capacities (DRC) are too low to be measured easily. Such lack of information has been hindering progress in developing personalized disease prevention and intervention protocols, especially among exposed populations. However, using a variety of challenge assays as biomarkers, variations in individual's DRC can be amplified in live cells and be determined. Furthermore, evidence indicates that DRC are not only inherited but can also be modified by environmental factors (e.g., nutritional status and exposure to genotoxic substances). Using these challenge assays, e.g., in live lymphocytes, individual's DRC can be holistically and functionally determined as well as quantitated. With the more precise information, assessment of health risk can be better determined on an individual rather than on a population basis. This review provides a succinct summary on the development and application of recent challenge assays in lymphocytes which can provide measurements of individuals' DRC, and on the latest data for more precise disease prevention and intervention.


Assuntos
Reparo do DNA , Neoplasias , Humanos , Reparo do DNA/genética , Linfócitos , Dano ao DNA/genética , Biomarcadores , Medição de Risco , DNA , Testes para Micronúcleos/métodos
4.
Diabetes ; 71(8): 1694-1705, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35594378

RESUMO

Identifying the mechanisms behind the ß-cell adaptation to failure is important to develop strategies to manage type 2 diabetes (T2D). Using db/db mice at early stages of the disease process, we took advantage of unbiased RNA sequencing to identify genes/pathways regulated by insulin resistance in ß-cells. We demonstrate herein that islets from 4-week-old nonobese and nondiabetic leptin receptor-deficient db/db mice exhibited downregulation of several genes involved in cell cycle regulation and DNA repair. We identified the transcription factor Yin Yang 1 (YY1) as a common gene between both pathways. The expression of YY1 and its targeted genes was decreased in the db/db islets. We confirmed the reduction in YY1 expression in ß-cells from diabetic db/db mice, mice fed a high-fat diet (HFD), and individuals with T2D. Chromatin immunoprecipitation sequencing profiling in EndoC-ßH1 cells, a human pancreatic ß-cell line, indicated that YY1 binding regions regulate cell cycle control and DNA damage recognition and repair. We then generated mouse models with constitutive and inducible YY1 deficiency in ß-cells. YY1-deficient mice developed diabetes early in life due to ß-cell loss. ß-Cells from these mice exhibited higher DNA damage, cell cycle arrest, and cell death as well as decreased maturation markers. Tamoxifen-induced YY1 deficiency in mature ß-cells impaired ß-cell function and induced DNA damage. In summary, we identified YY1 as a critical factor for ß-cell DNA repair and cell cycle progression.


Assuntos
Diabetes Mellitus Tipo 2 , Fator de Transcrição YY1/metabolismo , Animais , Ciclo Celular/genética , Reparo do DNA/genética , Diabetes Mellitus Tipo 2/genética , Humanos , Camundongos , Fator de Transcrição YY1/genética , Yin-Yang
5.
Clin Cancer Res ; 28(7): 1372-1382, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35022323

RESUMO

PURPOSE: Loss of TGFß signaling increases error-prone alternative end-joining (alt-EJ) DNA repair. We previously translated this mechanistic relationship as TGFß and alt-EJ gene expression signatures, which we showed are anticorrelated across cancer types. A score representing anticorrelation, ßAlt, predicts patient outcome in response to genotoxic therapy. Here we sought to verify this biology in live specimens and additional datasets. EXPERIMENTAL DESIGN: Human head and neck squamous carcinoma (HNSC) explants were treated in vitro to test whether the signatures report TGFß signaling, indicated by SMAD2 phosphorylation, and unrepaired DNA damage, indicated by persistent 53BP1 foci after irradiation or olaparib. A custom NanoString assay was implemented to analyze the signatures' expression in explants. Each signature gene was then weighted by its association with functional responses to define a modified score, ßAltw, that was retested for association with response to genotoxic therapies in independent datasets. RESULTS: Most genes in each signature were positively correlated with the expected biological response in tumor explants. Anticorrelation of TGFß and alt-EJ signatures measured by NanoString was confirmed in explants. ßAltw was significantly (P < 0.001) better than ßAlt in predicting overall survival in response to genotoxic therapy in The Cancer Genome Atlas (TCGA) pancancer patients and in independent HNSC and ovarian cancer patient datasets. CONCLUSIONS: Association of the TGFß and alt-EJ signatures with their biological response validates TGFß competency as a key mediator of DNA repair that can be readily assayed by gene expression. The predictive value of ßAltw supports its development to assist in clinical decision making.


Assuntos
Reparo do DNA por Junção de Extremidades , Neoplasias de Cabeça e Pescoço , Quebras de DNA de Cadeia Dupla , Dano ao DNA/genética , Reparo do DNA por Junção de Extremidades/genética , Reparo do DNA/genética , Humanos , Carcinoma de Células Escamosas de Cabeça e Pescoço , Fator de Crescimento Transformador beta/genética
6.
Prostate ; 82(1): 107-119, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34674288

RESUMO

BACKGROUND: Germline mutations in several genes, mainly DNA repair genes, have been associated with prostate cancer (PCa) progression. However, primarily due to the rarity of mutations, statistical evidence for these associations is not consistently established. The objective of this study is to synthesize evidence from multiple studies using a meta-analysis. METHODS: Genes analyzed were chosen based on National Comprehensive Cancer Network guidelines recommendations (10 genes) and a commonly reported gene (NBN). PCa progression in this analysis was defined as either having metastases or PCa-specific mortality. We searched PubMed for papers published before April 26, 2021, using selected keywords. Pooled odds ratio (OR) was estimated in all races and Caucasians-only using both fixed- and random-effect models. RESULTS: The search identified 1028 papers and an additional five from a manual review of references. After a manual process that excluded noneligible studies, 11 papers remained, including a total of 3944 progressors and 20,054 nonprogressors. Combining results from these eligible studies, mutation carrier rates were significantly higher in progressors than nonprogressors for NBN, BRCA2, ATM (under both fixed- and random-effect models), for CHEK2 (under fixed-effect model only), and for PALB2 (under random-effect model only), p < 0.05. Pooled OR (95% confidence interval) was 6.38 (2.25-18.05), 3.41 (2.31; 5.03), 1.93 (1.17-3.20), and 1.53 (1.00-2.33) for NBN, BRCA2, ATM, and CHEK2, respectively, under fixed-effect model and 2.63 (1.12-6.13) for PALB2 under random-effect model. No significant association was found for the six remaining genes. Certainty of evidence was low for many genes due primarily to the limited number of eligible studies and mutation carriers. CONCLUSIONS: Statistical evidence for five genes was obtained in this first meta-analysis of germline mutations and PCa progression. While these results may help urologists and genetic counselors interpret germline testing results for PCa progression, more original studies are needed.


Assuntos
Reparo do DNA/genética , Metástase Neoplásica/genética , Neoplasias da Próstata , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteína BRCA2/genética , Proteínas de Ciclo Celular/genética , Quinase do Ponto de Checagem 2/genética , Proteína do Grupo de Complementação N da Anemia de Fanconi/genética , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Humanos , Masculino , Proteínas Nucleares/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/patologia
7.
Int J Radiat Biol ; 98(1): 60-68, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34714725

RESUMO

PURPOSE: High doses of gamma (γ) irradiation cause oxidative stress and DNA damage. Alternative oxidase (AOX) catalyzes the energy-dissipating cyanide-resistant alternative pathway in plant mitochondria and is an important part of the cellular defense network under stress conditions. In this study, Arabidopsis thaliana plants with an altered expression of the AOX1a gene were exposed by high dose-rate ionizing radiation to assess the expression of genes of DNA repair and pro-/antioxidant states to elucidate the functional significance of AOX in plant stress response. MATERIALS AND METHODS: Five-week-old A. thaliana plants, either with basal AOX1a gene expression (wild-type Colombia-0 (Col-0)), antisense silencing of AOX1a (AS-12), and overexpression of the gene (XX-2), were γ-irradiated at a dose of 200 Gy. Gene expression and biochemical analyses were performed 12 h after irradiation. RESULTS: Acute γ-irradiation caused different responses between the genotypes. XX-2 plants, either control or irradiated, showed the highest expression of AOX1a gene and AOX protein, and the lowest expression of DNA repair genes. Wild type and AS-12 plants exposed to γ-irradiation upregulated another stress-induced gene, AOX1d, and DNA repair genes. Furthermore, a higher activity of Mn-dependent superoxide dismutase (Mn-SOD) was observed in the irradiated AS-12 plants than in the untreated plants of this line. However, AS-12 plants were less effective than Col-0 plants in controlling the accumulation of the superoxide anion. XX-2 plants had the lowest reactive oxygen species (ROS) levels among the genotypes. CONCLUSIONS: AS-12 plants display a compensatory mechanism by increasing the expression of AOX1d and the synthesis of the AOX protein, as well as by Mn-SOD activation. However, these were insufficient to maintain the background level of embryonic lethal mutations, and thereby the reproductive capacity. These results highlight the importance of AOX in the successful adaptation of plants to acute γ-irradiation, and indicate that AOX1a plays a key role in the regulation of the stress response.


Assuntos
Arabidopsis , Antioxidantes/metabolismo , Arabidopsis/genética , Reparo do DNA/genética , Regulação da Expressão Gênica de Plantas , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Oxirredutases , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Superóxido Dismutase/metabolismo
8.
Arch Toxicol ; 95(10): 3407-3416, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34468814

RESUMO

Biofuels from vegetable oils or animal fats are considered to be more sustainable than petroleum-derived diesel fuel. In this study, we have assessed the effect of hydrogenated vegetable oil (HVO) exhaust on levels of DNA damage in peripheral blood mononuclear cells (PBMCs) as primary outcome, and oxidative stress and inflammation as mediators of genotoxicity. In a randomized cross-over study, healthy humans were exposed to filtered air, inorganic salt particles, exhausts from combustion of HVO in engines with aftertreatment [i.e. emission with nitrogen oxides and low amounts of particulate matter less than 2.5 µm (approximately 1 µg/m3)], or without aftertreatment (i.e. emission with nitrogen oxides and 93 ± 13 µg/m3 of PM2.5). The subjects were exposed for 3 h and blood samples were collected before, within 1 h after the exposure and 24 h after. None of the exposures caused generation of DNA strand breaks and oxidatively damaged DNA, or affected gene expression of factors related to DNA repair (Ogg1), antioxidant defense (Hmox1) or pro-inflammatory cytokines (Ccl2, Il8 and Tnfa) in PBMCs. The results from this study indicate that short-term HVO exhaust exposure is not associated with genotoxic hazard in humans.


Assuntos
Biocombustíveis/toxicidade , Exposição por Inalação/efeitos adversos , Material Particulado/toxicidade , Emissões de Veículos/toxicidade , Adulto , Antioxidantes/metabolismo , Estudos Cross-Over , Dano ao DNA/efeitos dos fármacos , Reparo do DNA/genética , Feminino , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Óxidos de Nitrogênio/análise , Estresse Oxidativo/efeitos dos fármacos , Óleos de Plantas/análise , Emissões de Veículos/análise , Adulto Jovem
9.
Mol Oncol ; 15(8): 2065-2083, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33931939

RESUMO

Resistance to adjuvant chemotherapy is a major clinical problem in the treatment of colorectal cancer (CRC). The aim of this study was to elucidate the role of an epithelial to mesenchymal transition (EMT)-inducing protein, ZEB2, in chemoresistance of CRC, and to uncover the underlying mechanism. We performed IHC for ZEB2 and association analyses with clinical outcomes on primary CRC and matched CRC liver metastases in compliance with observational biomarker study guidelines. ZEB2 expression in primary tumours was an independent prognostic marker of reduced overall survival and disease-free survival in patients who received adjuvant FOLFOX chemotherapy. ZEB2 expression was retained in 96% of liver metastases. The ZEB2-dependent EMT transcriptional programme activated nucleotide excision repair (NER) pathway largely via upregulation of the ERCC1 gene and other components in NER pathway, leading to enhanced viability of CRC cells upon oxaliplatin treatment. ERCC1-overexpressing CRC cells did not respond to oxaliplatin in vivo, as assessed using a murine orthotopic model in a randomised and blinded preclinical study. Our findings show that ZEB2 is a biomarker of tumour response to chemotherapy and risk of recurrence in CRC patients. We propose that the ZEB2-ERCC1 axis is a key determinant of chemoresistance in CRC.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Colorretais/genética , Reparo do DNA/genética , Proteínas de Ligação a DNA/genética , Endonucleases/genética , Transição Epitelial-Mesenquimal/genética , Transcrição Gênica , Homeobox 2 de Ligação a E-box com Dedos de Zinco/fisiologia , Animais , Linhagem Celular Tumoral , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Resistencia a Medicamentos Antineoplásicos , Fluoruracila/uso terapêutico , Humanos , Leucovorina/uso terapêutico , Neoplasias Hepáticas/secundário , Camundongos , Compostos Organoplatínicos/uso terapêutico , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Mol Cell ; 81(12): 2611-2624.e10, 2021 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-33857404

RESUMO

The Shieldin complex shields double-strand DNA breaks (DSBs) from nucleolytic resection. Curiously, the penultimate Shieldin component, SHLD1, is one of the least abundant mammalian proteins. Here, we report that the transcription factors THAP1, YY1, and HCF1 bind directly to the SHLD1 promoter, where they cooperatively maintain the low basal expression of SHLD1, thereby ensuring a proper balance between end protection and resection during DSB repair. The loss of THAP1-dependent SHLD1 expression confers cross-resistance to poly (ADP-ribose) polymerase (PARP) inhibitor and cisplatin in BRCA1-deficient cells and shorter progression-free survival in ovarian cancer patients. Moreover, the embryonic lethality and PARPi sensitivity of BRCA1-deficient mice is rescued by ablation of SHLD1. Our study uncovers a transcriptional network that directly controls DSB repair choice and suggests a potential link between DNA damage and pathogenic THAP1 mutations, found in patients with the neurodevelopmental movement disorder adult-onset torsion dystonia type 6.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Animais , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Proteínas de Ciclo Celular/genética , DNA/metabolismo , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Reparo do DNA por Junção de Extremidades/efeitos dos fármacos , Reparo do DNA/genética , Distonia/genética , Feminino , Fator C1 de Célula Hospedeira/metabolismo , Proteínas Mad2/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Poli(ADP-Ribose) Polimerase-1/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Reparo de DNA por Recombinação/efeitos dos fármacos , Proteínas de Ligação a Telômeros/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Fator de Transcrição YY1/metabolismo
11.
Sci Transl Med ; 13(580)2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33568520

RESUMO

Among the pleotropic roles of transforming growth factor-ß (TGFß) signaling in cancer, its impact on genomic stability is least understood. Inhibition of TGFß signaling increases use of alternative end joining (alt-EJ), an error-prone DNA repair process that typically functions as a "backup" pathway if double-strand break repair by homologous recombination or nonhomologous end joining is compromised. However, the consequences of this functional relationship on therapeutic vulnerability in human cancer remain unknown. Here, we show that TGFß broadly controls the DNA damage response and suppresses alt-EJ genes that are associated with genomic instability. Mechanistically based TGFß and alt-EJ gene expression signatures were anticorrelated in glioblastoma, squamous cell lung cancer, and serous ovarian cancer. Consistent with error-prone repair, more of the genome was altered in tumors classified as low TGFß and high alt-EJ, and the corresponding patients had better outcomes. Pan-cancer analysis of solid neoplasms revealed that alt-EJ genes were coordinately expressed and anticorrelated with TGFß competency in 16 of 17 cancer types tested. Moreover, regardless of cancer type, tumors classified as low TGFß and high alt-EJ were characterized by an insertion-deletion mutation signature containing short microhomologies and were more sensitive to genotoxic therapy. Collectively, experimental studies revealed that loss or inhibition of TGFß signaling compromises the DNA damage response, resulting in ineffective repair by alt-EJ. Translation of this mechanistic relationship into gene expression signatures identified a robust anticorrelation that predicts response to genotoxic therapies, thereby expanding the potential therapeutic scope of TGFß biology.


Assuntos
Reparo do DNA por Junção de Extremidades , Neoplasias , Quebras de DNA de Cadeia Dupla , Dano ao DNA , Reparo do DNA/genética , Humanos , Neoplasias/genética , Fator de Crescimento Transformador beta
12.
Gene ; 781: 145488, 2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-33588040

RESUMO

Oxidative stress (OS) plays an essential role in demyelination and tissue injury related to pathogenesis of multiple sclerosis (MS). On the other hand, vitamin D (VD) as an antioxidant reduces oxidative stress and has been used as adjuvant therapy in autoimmune diseases. Although VD supplementation is suggested as a protective and immunomodulation factor for MS patients, the molecular mechanisms remain unclear. Given that VD may modulate the immune system of MS patients through the DNA repair pathway, we aimed to evaluate the effects of VD supplementation in DNA repair genes expression including OGG1, MYH, MTH1, and ITPA. Transcript levels were measured using the RT-qPCR method in peripheral blood mononuclear cells (PBMCs) of relapsing-remitting multiple sclerosis (RRMS) patients before and after two months of VD supplementation. Furthermore, in silico analysis and correlation gene expression analysis was performed to find the biological binding sites and the effect of NRF2 on the regulation of DNA repair genes. Our data revealed that in MS patients, 2-month VD treatment significantly altered the expression of MYH, OGG1, MTH1, and NRF2 genes. A significant correlation was observed between DNA repair genes and NRF2 expression, which was confirmed by the presence of antioxidant response element (ARE) binding sites in the promoter of OGG1, MYH, and MTH1 genes. This study demonstrated that the impact of VD on MS patients may be mediated through the improvement of DNA repair system efficiency. This finding brought some new evidence for the involvement of DNA repair genes in the physiopathology of MS patients.


Assuntos
Reparo do DNA/genética , Expressão Gênica/efeitos dos fármacos , Esclerose Múltipla/genética , Vitamina D/farmacologia , Vitaminas/farmacologia , Adulto , Simulação por Computador , DNA Glicosilases/genética , Reparo do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/genética , Feminino , Humanos , Masculino , Esclerose Múltipla/tratamento farmacológico , Fator 2 Relacionado a NF-E2/genética , Monoéster Fosfórico Hidrolases/genética , Reação em Cadeia da Polimerase em Tempo Real
13.
Environ Geochem Health ; 43(12): 4905-4917, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33486627

RESUMO

Deinococcus indicus is a novel bacteria isolated from West Bengal, India known for its UV radiation and heavy metal tolerance. Since, this organism is reported from a region known for heavy metal contamination and earlier investigations demonstrated its radiation resistance, our study focused on the multiple stress responsive and DNA repair mechanisms. Though, most of the members of the genus Deinococcus are Gram positive cocci, D. indicus postures Gram negative rod shaped cells. Hence, the objectives were framed precisely to understand DNA repair pathway and stress responsive genes expression with a broader perspective. Based on available whole genome sequence of D. indicus, quantitative real time PCR (qPCR) was done to determine the expression pattern of multiple stress responsive genes upon various environmental extremities. Among them, UV responsive genes like UvrD and UvsE showed elevated expression when subjected to UV-C radiation at different time intervals. Similarly, when supplemented with arsenic and chromium, ArsR and ArsB exhibited considerably higher level of expression. While all the genes were subsequently analyzed in-silico, depicted that most of them were with N-glycosylation site, GPI anchor sites, N-terminal trans-membrane helix region besides putative signal peptides. Overall, this study opined the functional information on stress tolerance genes that aid to understand the DNA damage recovery mechanism towards elucidation of DNA repair pathways.


Assuntos
Arsênio , Deinococcus , Reparo do DNA/genética , Ambientes Extremos
14.
Science ; 371(6524)2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33384351

RESUMO

The circadian clock coordinates daily rhythmicity of biochemical, physiologic, and behavioral functions in humans. Gene expression, cell division, and DNA repair are modulated by the clock, which gives rise to the hypothesis that clock dysfunction may predispose individuals to cancer. Although the results of many epidemiologic and animal studies are consistent with there being a role for the clock in the genesis and progression of tumors, available data are insufficient to conclude that clock disruption is generally carcinogenic. Similarly, studies have suggested a circadian time-dependent efficacy of chemotherapy, but clinical trials of chronochemotherapy have not demonstrated improved outcomes compared with conventional regimens. Future hypothesis-driven and discovery-oriented research should focus on specific interactions between clock components and carcinogenic mechanisms to realize the full clinical potential of the relationship between clocks and cancer.


Assuntos
Antineoplásicos/uso terapêutico , Carcinogênese/genética , Relógios Circadianos/genética , Cronofarmacoterapia , Neoplasias/tratamento farmacológico , Neoplasias/genética , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Proteínas CLOCK/genética , Ritmo Circadiano/genética , Reparo do DNA/genética , Genes Supressores de Tumor , Humanos , Camundongos , Proteínas do Tecido Nervoso/genética , Oncogenes , Polimorfismo Genético
15.
Nat Biotechnol ; 39(1): 35-40, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32690970

RESUMO

Current base editors (BEs) catalyze only base transitions (C to T and A to G) and cannot produce base transversions. Here we present BEs that cause C-to-A transversions in Escherichia coli and C-to-G transversions in mammalian cells. These glycosylase base editors (GBEs) consist of a Cas9 nickase, a cytidine deaminase and a uracil-DNA glycosylase (Ung). Ung excises the U base created by the deaminase, forming an apurinic/apyrimidinic (AP) site that initiates the DNA repair process. In E. coli, we used activation-induced cytidine deaminase (AID) to construct AID-nCas9-Ung and found that it converts C to A with an average editing specificity of 93.8% ± 4.8% and editing efficiency of 87.2% ± 6.9%. For use in mammalian cells, we replaced AID with rat APOBEC1 (APOBEC-nCas9-Ung). We tested APOBEC-nCas9-Ung at 30 endogenous sites, and we observed C-to-G conversions with a high editing specificity at the sixth position of the protospacer between 29.7% and 92.2% and an editing efficiency between 5.3% and 53.0%. APOBEC-nCas9-Ung supplements the current adenine and cytidine BEs (ABE and CBE, respectively) and could be used to target G/C disease-causing mutations.


Assuntos
Sistemas CRISPR-Cas/genética , Citosina/metabolismo , DNA Glicosilases , Edição de Genes/métodos , Desaminase APOBEC-1/genética , Desaminase APOBEC-1/metabolismo , Adenina/metabolismo , Animais , Pareamento de Bases/genética , Proteína 9 Associada à CRISPR/genética , Proteína 9 Associada à CRISPR/metabolismo , Citidina Desaminase , Reparo do DNA/genética , Desoxirribonuclease I/genética , Desoxirribonuclease I/metabolismo , Escherichia coli/genética , Guanina/metabolismo , Ratos , Uracila-DNA Glicosidase
16.
Endocr Relat Cancer ; 28(2): R55-R66, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33300498

RESUMO

Co-ordinated oscillation of mammalian circadian clock and cell cycle is essential for cellular and organismal homeostasis. Existing preclinical, epidemiological, molecular and biochemical evidence reveals a robust interplay between circadian clock, genome instability and cancer. Furthermore, recent investigations have demonstrated that the alterations in circadian clock perturb genome stability by modulating the cell-cycle timing, altering DNA replication fork progression, influencing DNA damage response (DDR) and DNA repair efficiency. In this review, we examine the most recent findings from different eukaryotic model systems and discuss the functional interaction between circadian factors with key DNA replication, DDR and DNA repair genes.


Assuntos
Relógios Circadianos , Ritmo Circadiano , Animais , Ciclo Celular , Relógios Circadianos/genética , Ritmo Circadiano/genética , Dano ao DNA/genética , Reparo do DNA/genética
17.
Nat Commun ; 11(1): 2950, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32528002

RESUMO

During homologous recombination, Rad51 forms a nucleoprotein filament on single-stranded DNA to promote DNA strand exchange. This filament binds to double-stranded DNA (dsDNA), searches for homology, and promotes transfer of the complementary strand, producing a new heteroduplex. Strand exchange proceeds via two distinct three-strand intermediates, C1 and C2. C1 contains the intact donor dsDNA whereas C2 contains newly formed heteroduplex DNA. Here, we show that the conserved DNA binding motifs, loop 1 (L1) and loop 2 (L2) in site I of Rad51, play distinct roles in this process. L1 is involved in formation of the C1 complex whereas L2 mediates the C1-C2 transition, producing the heteroduplex. Another DNA binding motif, site II, serves as the DNA entry position for initial Rad51 filament formation, as well as for donor dsDNA incorporation. Our study provides a comprehensive molecular model for the catalytic process of strand exchange mediated by eukaryotic RecA-family recombinases.


Assuntos
DNA/metabolismo , Rad51 Recombinase/química , Rad51 Recombinase/metabolismo , Trifosfato de Adenosina/metabolismo , Sítios de Ligação/genética , DNA/genética , Dano ao DNA/genética , Dano ao DNA/fisiologia , Reparo do DNA/genética , Reparo do DNA/fisiologia , DNA de Cadeia Simples/genética , Recombinação Homóloga/genética , Recombinação Homóloga/fisiologia , Humanos , Mutação/genética , Ácidos Nucleicos Heteroduplexes/genética , Ácidos Nucleicos Heteroduplexes/metabolismo , Estrutura Secundária de Proteína , Rad51 Recombinase/genética , Saccharomyces cerevisiae/genética , Schizosaccharomyces/genética
18.
J Intern Med ; 287(6): 685-697, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32176378

RESUMO

Mutations in the mitochondrial genome are the cause of many debilitating neuromuscular disorders. Currently, there is no cure or treatment for these diseases, and symptom management is the only relief doctors can provide. Although supplements and vitamins are commonly used in treatment, they provide little benefit to the patient and are only palliative. This is why gene therapy is a promising research topic to potentially treat and, in theory, even cure diseases caused by mutations in the mitochondrial DNA (mtDNA). Mammalian cells contain approximately a thousand copies of mtDNA, which can lead to a phenomenon called heteroplasmy, where both wild-type and mutant mtDNA molecules co-exist within the cell. Disease only manifests once the per cent of mutant mtDNA reaches a high threshold (usually >80%), which causes mitochondrial dysfunction and reduced ATP production. This is a useful feature to take advantage of for gene therapy applications, as not every mutant copy of mtDNA needs to be eliminated, but only enough to shift the heteroplasmic ratio below the disease threshold. Several DNA-editing enzymes have been used to shift heteroplasmy in cell culture and mice. This review provides an overview of these enzymes and discusses roadblocks of applying these to gene therapy in humans.


Assuntos
Enzimas Reparadoras do DNA/genética , DNA Mitocondrial/genética , Terapia Genética , Heteroplasmia/genética , Animais , Reparo do DNA/genética , Enzimas Reparadoras do DNA/uso terapêutico , Terapia Genética/métodos , Humanos , Doenças Mitocondriais
19.
Mol Pharmacol ; 97(2): 72-89, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31787618

RESUMO

Wnts are secreted proteins that bind to cell surface receptors to activate downstream signaling cascades. Normal Wnt signaling plays key roles in embryonic development and adult tissue homeostasis. The secretion of Wnt ligands, the turnover of Wnt receptors, and the signaling transduction are tightly regulated and fine-tuned to keep the signaling output "just right." Hyperactivated Wnt signaling due to recurrent genetic alterations drives several human cancers. Elevated Wnt signaling also confers resistance to multiple conventional and targeted cancer therapies through diverse mechanisms including maintaining the cancer stem cell population, enhancing DNA damage repair, facilitating transcriptional plasticity, and promoting immune evasion. Different classes of Wnt signaling inhibitors targeting key nodes of the pathway have been developed and show efficacy in treating Wnt-driven cancers and subverting Wnt-mediated therapy resistance in preclinical studies. Several of these inhibitors have advanced to clinical trials, both singly and in combination with other existing US Food and Drug Administration-approved anti-cancer modalities. In the near future, pharmacological inhibition of Wnt signaling may be a real choice for patients with cancer. SIGNIFICANCE STATEMENT: The latest insights in Wnt signaling, ranging from basic biology to therapeutic implications in cancer, are reviewed. Recent studies extend understanding of this ancient signaling pathway and describe the development and improvement of anti-Wnt therapeutic modalities for cancer.


Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias/tratamento farmacológico , Proteínas Wnt/metabolismo , Via de Sinalização Wnt/genética , Animais , Antineoplásicos/uso terapêutico , Carcinogênese/genética , Ensaios Clínicos como Assunto , Dano ao DNA/efeitos dos fármacos , Reparo do DNA/genética , Avaliação Pré-Clínica de Medicamentos , Humanos , Ligantes , Terapia de Alvo Molecular/métodos , Mutação , Neoplasias/genética , Neoplasias/patologia , Células-Tronco Neoplásicas/patologia , Proteínas Wnt/antagonistas & inibidores , Proteínas Wnt/genética , Via de Sinalização Wnt/efeitos dos fármacos
20.
Crit Rev Food Sci Nutr ; 60(8): 1375-1387, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30729798

RESUMO

Due to change in lifestyle and food habits, people are more at risk of diet-related diseases and cancers. It is also established that dietary modifications significantly reduce the risk of diseases. Nutrigenomics is relatively fresh discipline, but possess an enormous potential that can apply for prevention and management of certain carcinomas and diseases. This review enables us to generate useful information for scientists and health professionals regarding the role of Nutrigenomics in the prevention of diet and lifestyle-related diseases like cancer. It influences health conditions of individuals and susceptibility of disease by defining the metabolic response and gene expression. Epigenetic modifications can perform a significant role in disease occurrence and pathogenesis. DNA methylation and chromatin remodeling are the most common epigenetic mechanisms. Omega 3 fatty acids are the best example of nutrients and gene interaction not involving DNA methylation while certain bioactive food compounds have a proven role in cancer prevention through an epigenetic mechanism. Dietary polyphenols substantially take part in prevention of oral, breast, skin, esophageal, colorectal, prostate, pancreatic and lung cancers. Moreover, minerals and vitamins involve regulatory processes. Zinc, Selenium and folate involve in DNA repairing process have anticancer properties. Consumption of multivitamins prevents methylation of cancer cells.


Assuntos
Dieta , Epigênese Genética , Neoplasias/genética , Neoplasias/prevenção & controle , Nutrigenômica , Metilação de DNA , Reparo do DNA/genética , Humanos
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