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1.
Int J Mol Sci ; 24(16)2023 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-37628896

RESUMO

After cellular differentiation, nuclear DNA is no longer replicated, and many of the associated proteins are downregulated accordingly. These include the structure-specific endonucleases Fen1 and DNA2, which are implicated in repairing mitochondrial DNA (mtDNA). Two more such endonucleases, named MGME1 and ExoG, have been discovered in mitochondria. This category of nuclease is required for so-called "long-patch" (multinucleotide) base excision DNA repair (BER), which is necessary to process certain oxidative lesions, prompting the question of how differentiation affects the availability and use of these enzymes in mitochondria. In this study, we demonstrate that Fen1 and DNA2 are indeed strongly downregulated after differentiation of neuronal precursors (Cath.a-differentiated cells) or mouse myotubes, while the expression levels of MGME1 and ExoG showed minimal changes. The total flap excision activity in mitochondrial extracts of these cells was moderately decreased upon differentiation, with MGME1 as the predominant flap endonuclease and ExoG playing a lesser role. Unexpectedly, both differentiated cell types appeared to accumulate less oxidative or alkylation damage in mtDNA than did their proliferating progenitors. Finally, the overall rate of mtDNA repair was not significantly different between proliferating and differentiated cells. Taken together, these results indicate that neuronal cells maintain mtDNA repair upon differentiation, evidently relying on mitochondria-specific enzymes for long-patch BER.


Assuntos
DNA Mitocondrial , Endonucleases Flap , Animais , Camundongos , Endonucleases Flap/genética , Diferenciação Celular , DNA Mitocondrial/genética , Fibras Musculares Esqueléticas , Reparo do DNA , Endonucleases
2.
Arch Biochem Biophys ; 710: 108977, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34174223

RESUMO

As mitochondria are vulnerable to oxidative damage and represent the main source of reactive oxygen species (ROS), they are considered key tuners of ROS metabolism and buffering, whose dysfunction can progressively impact neuronal networks and disease. Defects in DNA repair and DNA damage response (DDR) may also affect neuronal health and lead to neuropathology. A number of congenital DNA repair and DDR defective syndromes, indeed, show neurological phenotypes, and a growing body of evidence indicate that defects in the mechanisms that control genome stability in neurons acts as aging-related modifiers of common neurodegenerative diseases such as Alzheimer, Parkinson's, Huntington diseases and Amyotrophic Lateral Sclerosis. In this review we elaborate on the established principles and recent concepts supporting the hypothesis that deficiencies in either DNA repair or DDR might contribute to neurodegeneration via mechanisms involving mitochondrial dysfunction/deranged metabolism.


Assuntos
Mitocôndrias/genética , Mitocôndrias/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Dano ao DNA , Reparo do DNA , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Genoma Humano , Genoma Mitocondrial , Instabilidade Genômica , Humanos , Redes e Vias Metabólicas , Dinâmica Mitocondrial , Mitofagia , Modelos Neurológicos , Mutação , Doenças Neurodegenerativas/prevenção & controle , Espécies Reativas de Oxigênio/metabolismo
3.
Int J Mol Sci ; 22(13)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34281194

RESUMO

Cockayne syndrome group A (CS-A) is a rare recessive progeroid disorder characterized by sun sensitivity and neurodevelopmental abnormalities. Cells derived from CS-A patients present as pathological hallmarks excessive oxidative stress, mitochondrial fragmentation and apoptosis associated with hyperactivation of the mitochondrial fission dynamin related protein 1 (DRP1). In this study, by using human cell models we further investigated the interplay between DRP1 and CSA and we determined whether pharmacological or genetic inhibition of DRP1 affects disease progression. Both reactive oxygen and nitrogen species are in excess in CS-A cells and when the mitochondrial translocation of DRP1 is inhibited a reduction of these species is observed together with a recovery of mitochondrial integrity and a significant decrease of apoptosis. This study indicates that the CSA-driven modulation of DRP1 pathway is key to control mitochondrial homeostasis and apoptosis and suggests DRP1 as a potential target in the treatment of CS patients.


Assuntos
Síndrome de Cockayne/metabolismo , Dinaminas/metabolismo , Mitocôndrias/metabolismo , Animais , Apoptose/genética , Linhagem Celular , Síndrome de Cockayne/fisiopatologia , Progressão da Doença , Dinaminas/genética , Humanos , Proteínas Associadas aos Microtúbulos/metabolismo , Mitocôndrias/fisiologia , Doenças Mitocondriais/genética , Doenças Mitocondriais/metabolismo , Proteínas Mitocondriais/metabolismo , Modelos Biológicos , Estresse Oxidativo , Quinazolinonas/metabolismo , Quinazolinonas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais
4.
Int J Mol Sci ; 22(18)2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34575853

RESUMO

Furan is a volatile compound that is formed in foods during thermal processing. It is classified as a possible human carcinogen by international authorities based on sufficient evidence of carcinogenicity from studies in experimental animals. Although a vast number of studies both in vitro and in vivo have been performed to investigate furan genotoxicity, the results are inconsistent, and its carcinogenic mode of action remains to be clarified. Here, we address the mutagenic and clastogenic activity of furan and its prime reactive metabolite cis-2 butene-1,4-dial (BDA) in mammalian cells in culture and in mouse animal models in a search for DNA lesions responsible of these effects. To this aim, Fanconi anemia-derived human cell lines defective in the repair of DNA inter-strand crosslinks (ICLs) and Ogg1-/- mice defective in the removal of 8-hydroxyguanine from DNA, were used. We show that both furan and BDA present a weak (if any) mutagenic activity but are clear inducers of clastogenic damage. ICLs are strongly indicated as key lesions for chromosomal damage whereas oxidized base lesions are unlikely to play a critical role.


Assuntos
Aberrações Cromossômicas/induzido quimicamente , Furanos/efeitos adversos , Mutação/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Animais , Carcinógenos , Linhagem Celular , Dano ao DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Furanos/toxicidade , Humanos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Camundongos , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Mutagênicos , Oxirredução
5.
Epidemiol Prev ; 43(4): 223-237, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31650778

RESUMO

BACKGROUND: human exposure to mixtures of chemicals of toxicological interest, typically found in industrial contaminated sites (ICSs), has been associated with a broad range of different health outcomes. Deprived population groups endure most of the burden of disease and premature death associated to the exposure to those pollutants. Characterising the impacts on health of an ICS is a challenging process. Currently the two main methodological approaches used are Human Health Risk Assessment (HHRA) and Environmental Epidemiological (EE) studies. OBJECTIVES: review existing guidance and scientific evidence for HHRA and EE studies applied to contaminated sites that orientate in selecting the most suitable methodological approach for characterising health impacts in ICSs according to the site characteristics, and the availability of environmental, health and sociodemographic data. RESULTS: HHRA has evolved into a more holistic approach, placing more emphasis in planning, community involvement and adapting the dimension of the assessment to the problem formulation and to the availability of resources. Many different HHRA guidelines for contaminated sites has been published worldwide, and although they share a similar framework, the scientific evidence used for deriving reference values and the variet of policy options can result in a wide variability of health risk estimates. This paper condenses different options with the recommendations to use those tools, default values for environmental and exposure levels and toxicological reference values that most suit to the population and characteristics of the ICSs under evaluation. CONCLUSIONS: the suitability to use one or another approach to assess the impact of ICSs on health depends on the availability of data, cost-benefit aspects and the kind of problem that needs to be answered. Risk assessment based on toxicological data can be very rapid and cheap, providing direct information when the intervention to protect the health of population is urgent and no suitable dose-response functions are available from epidemiological studies. Conducting EE studies provide a deeper insight into the problem of the exposure to industrial pollutants that do not require extrapolation from data obtained from toxicological studies or other population, addressing the community concern's more directly. Complementing the results obtained from different approaches, including those from public health surveillance systems, might provide an efficient and complete response to the impact of ICSs.


Assuntos
Coleta de Dados , Exposição Ambiental , Poluentes Ambientais/efeitos adversos , Estudos Epidemiológicos , Avaliação do Impacto na Saúde/métodos , Indústrias , Medição de Risco/métodos , Humanos , Itália
6.
Neural Plast ; 2016: 3619274, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26942017

RESUMO

There is a growing body of evidence indicating that the mechanisms that control genome stability are of key importance in the development and function of the nervous system. The major threat for neurons is oxidative DNA damage, which is repaired by the base excision repair (BER) pathway. Functional mutations of enzymes that are involved in the processing of single-strand breaks (SSB) that are generated during BER have been causally associated with syndromes that present important neurological alterations and cognitive decline. In this review, the plasticity of BER during neurogenesis and the importance of an efficient BER for correct brain function will be specifically addressed paying particular attention to the brain region and neuron-selectivity in SSB repair-associated neurological syndromes and age-related neurodegenerative diseases.


Assuntos
Encéfalo/metabolismo , Dano ao DNA , Reparo do DNA , Doenças do Sistema Nervoso/genética , Neurônios/metabolismo , Estresse Oxidativo , Animais , Quebras de DNA de Cadeia Simples , Humanos , Neurogênese/genética
7.
EFSA J ; 22(7): e8844, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38957748

RESUMO

The European Commission asked EFSA for a risk assessment on small organoarsenic species in food. For monomethylarsonic acid MMA(V), decreased body weight resulting from diarrhoea in rats was identified as the critical endpoint and a BMDL10 of 18.2 mg MMA(V)/kg body weight (bw) per day (equivalent to 9.7 mg As/kg bw per day) was calculated as a reference point (RP). For dimethylarsinic acid DMA(V), increased incidence in urinary bladder tumours in rats was identified as the critical endpoint. A BMDL10 of 1.1 mg DMA(V)/kg bw per day (equivalent to 0.6 mg As/kg bw per day) was calculated as an RP. For other small organoarsenic species, the toxicological data are insufficient to identify critical effects and RPs, and they could not be included in the risk assessment. For both MMA(V) and DMA(V), the toxicological database is incomplete and a margin of exposure (MOE) approach was applied for risk characterisation. The highest chronic dietary exposure to DMA(V) was estimated in 'Toddlers', with rice and fish meat as the main contributors across population groups. For MMA(V), the highest chronic dietary exposures were estimated for high consumers of fish meat and processed/preserved fish in 'Infants' and 'Elderly' age class, respectively. For MMA(V), an MOE of ≥ 500 was identified not to raise a health concern. For MMA(V), all MOEs were well above 500 for average and high consumers and thus do not raise a health concern. For DMA(V), an MOE of 10,000 was identified as of low health concern as it is genotoxic and carcinogenic, although the mechanisms of genotoxicity and its role in carcinogenicity of DMA(V) are not fully elucidated. For DMA(V), MOEs were below 10,000 in many cases across dietary surveys and age groups, in particular for some 95th percentile exposures. The Panel considers that this would raise a health concern.

8.
EFSA J ; 22(1): e8488, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38239496

RESUMO

The European Commission asked EFSA to update its 2009 risk assessment on arsenic in food carrying out a hazard assessment of inorganic arsenic (iAs) and using the revised exposure assessment issued by EFSA in 2021. Epidemiological studies show that the chronic intake of iAs via diet and/or drinking water is associated with increased risk of several adverse outcomes including cancers of the skin, bladder and lung. The CONTAM Panel used the benchmark dose lower confidence limit based on a benchmark response (BMR) of 5% (relative increase of the background incidence after adjustment for confounders, BMDL05) of 0.06 µg iAs/kg bw per day obtained from a study on skin cancer as a Reference Point (RP). Inorganic As is a genotoxic carcinogen with additional epigenetic effects and the CONTAM Panel applied a margin of exposure (MOE) approach for the risk characterisation. In adults, the MOEs are low (range between 2 and 0.4 for mean consumers and between 0.9 and 0.2 at the 95th percentile exposure, respectively) and as such raise a health concern despite the uncertainties.

9.
Mutat Res ; 743-744: 160-168, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23562804

RESUMO

Damage to genomic DNA triggers a prompt set of signaling events known as the DNA damage response (DDR) which coordinates DNA repair, cell cycle arrest and ultimately cell death or senescence. Although activation of adequate DNA damage signaling and repair systems depends on the type of lesion and the cell-cycle phase in which it occurs, emerging evidence indicates that DNA repair and DDR function differently in different cellular contexts. Depending on the time maintenance and function of a specific cell type the risk of accumulating DNA damage may vary. For instance, damage to stem cells if not repaired can lead to mutation amplification or propagation through the processes of self-renewal and differentiation, respectively, whereas damage to post-mitotic cells can affect mostly tissue homeostasis. Stem cells are therefore expected to address DNA damage differently from their somatic counterparts. In this review the information available on the common and distinct mechanisms of control of genome integrity utilized by different cell types along the self-renewal/differentiation program will be reviewed, with special emphasis on their roles in the prevention of aging and disease.


Assuntos
Diferenciação Celular/genética , Dano ao DNA/genética , Reparo do DNA , Transdução de Sinais/genética , Animais , Morte Celular/genética , Humanos
10.
Mutat Res ; 749(1-2): 73-9, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23727398

RESUMO

Due to the great number of genes involved in DNA repair and the interactions among the pathways responsible for the repair of different types of DNA damage, there is an increasing need for simple and reliable approaches to phenotypically assess DNA repair capacity (DRC). The use of peripheral blood mononuclear cells (PBMCs) in DRC assays is particularly useful for human monitoring studies. However, in such studies it is not always possible to collect and process samples on the same day as the blood is taken. We performed a genotype-phenotype correlation study on DRC on 225 healthy subjects. Due to the large number of blood samples to be processed, PBMCs were either isolated and cryopreserved on the same day of blood collection (day 1) or on the following day after 24h blood storage at room temperature (day 2-RT). Samples processed in different days showed a significant difference in the DRC evaluated as 8-oxoguanine glycosylase activity (OGG assay) in cell extracts (p<0.0001) and as benzo[a]pyrene diol epoxide (BPDE)-induced damage repair by the comet assay (p=0.05). No apparent effect of the blood storage conditions on the outcome of γ-ray induced H2AX phosphorylation assay was reported. These results prompted us to further analyze the effects of blood storage conditions by performing a validation study. Three blood samples were simultaneously taken from ten healthy donors, PBMCs were isolated and cryopreserved as follows: immediately after blood collection (day 1); on the following day, after blood storage at RT (day 2-RT); or after blood storage at 4°C (day 2-4°C). DRC was then evaluated using phenotypic assays. The γ-ray induced H2AX phosphorylation assay has been confirmed as the only assay that showed good reproducibility independently of the blood storage conditions. The measurement of OGG assay was most affected by the blood storage conditions.


Assuntos
Preservação de Sangue/métodos , Reparo do DNA/fisiologia , Leucócitos Mononucleares/metabolismo , Adolescente , Adulto , Preservação de Sangue/efeitos adversos , Coleta de Amostras Sanguíneas/efeitos adversos , Coleta de Amostras Sanguíneas/métodos , Ensaio Cometa , Criopreservação , Feminino , Estudos de Associação Genética/normas , Humanos , Masculino , Pessoa de Meia-Idade , Temperatura , Adulto Jovem
11.
Mutat Res ; 731(1-2): 1-13, 2012 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22155132

RESUMO

Oxidative damage to DNA can cause mutations, and mutations can lead to cancer. DNA repair of oxidative damage should therefore play a pivotal role in defending humans against cancer. This is exemplified by the increased risk of colorectal cancer of patients with germ-line mutations of the oxidative damage DNA glycosylase MUTYH. In contrast to germ-line mutations in DNA repair genes, which cause a strong deficiency in DNA repair activity in all cell types, the role of single nucleotide polymorphisms (SNPs) in sporadic cancer is unclear also because deficiencies in DNA repair, if any, are expected to be much milder. Further slowing down progress are the paucity of accurate and reproducible functional assays and poor epidemiological design of many studies. This review will focus on the most common and widely studied SNPs of oxidative DNA damage repair proteins trying to bridge the information available on biochemical and structural features of the repair proteins with the functional effects of these variants and their potential impact on the pathogenesis of disease.


Assuntos
Dano ao DNA , Reparo do DNA/genética , Polimorfismo de Nucleotídeo Único , Espécies Reativas de Oxigênio/metabolismo , Enzimas Reparadoras do DNA/genética , Humanos , Mutação , Relação Estrutura-Atividade
12.
Mutat Res ; 736(1-2): 104-16, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22732424

RESUMO

Oxidative damage to DNA can cause mutations, and mutations can lead to cancer. DNA repair of oxidative damage should therefore play a pivotal role in defending humans against cancer. This is exemplified by the increased risk of colorectal cancer of patients with germ-line mutations of the oxidative damage DNA glycosylase MUTYH. In contrast to germ-line mutations in DNA repair genes, which cause a strong deficiency in DNA repair activity in all cell types, the role of single nucleotide polymorphisms (SNPs) in sporadic cancer is unclear also because deficiencies in DNA repair, if any, are expected to be much milder. Further slowing down progress are the paucity of accurate and reproducible functional assays and poor epidemiological design of many studies. This review will focus on the most common and widely studied SNPs of oxidative DNA damage repair proteins trying to bridge the information available on biochemical and structural features of the repair proteins with the functional effects of these variants and their potential impact on the pathogenesis of disease.

13.
Clin Epigenetics ; 14(1): 176, 2022 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-36528638

RESUMO

BACKGROUND: Obesity is a multifactorial and chronic condition of growing universal concern. It has recently been reported that bariatric surgery is a more successful treatment for severe obesity than other noninvasive interventions, resulting in rapid significant weight loss and associated chronic disease remission. The identification of distinct epigenetic patterns in patients who are obese or have metabolic imbalances has suggested a potential role for epigenetic alterations in causal or mediating pathways in the development of obesity-related pathologies. Specific changes in the epigenome (DNA methylome), associated with metabolic disorders, can be detected in the blood. We investigated whether such epigenetic changes are reversible after weight loss using genome-wide DNA methylome analysis of blood samples from individuals with severe obesity (mean BMI ~ 45) undergoing bariatric surgery. RESULTS: Our analysis revealed 41 significant (Bonferroni p < 0.05) and 1169 (false discovery rate p < 0.05) suggestive differentially methylated positions (DMPs) associated with weight loss due to bariatric surgery. Among the 41 significant DMPs, 5 CpGs were replicated in an independent cohort of BMI-discordant monozygotic twins (the heavier twin underwent diet-induced weight loss). The effect sizes of these 5 CpGs were consistent across discovery and replication sets (p < 0.05). We also identified 192 differentially methylated regions (DMRs) among which SMAD6 and PFKFB3 genes were the top hypermethylated and hypomethylated regions, respectively. Pathway enrichment analysis of the DMR-associated genes showed that functional pathways related to immune function and type 1 diabetes were significant. Weight loss due to bariatric surgery also significantly decelerated epigenetic age 12 months after the intervention (mean = - 4.29; p = 0.02). CONCLUSIONS: We identified weight loss-associated DNA-methylation alterations targeting immune and inflammatory gene pathways in blood samples from bariatric-surgery patients. The top hits were replicated in samples from an independent cohort of BMI-discordant monozygotic twins following a hypocaloric diet. Energy restriction and bariatric surgery thus share CpGs that may represent early indicators of response to the metabolic effects of weight loss. The analysis of bariatric surgery-associated DMRs suggests that epigenetic regulation of genes involved in endothelial and adipose tissue function is key in the pathophysiology of obesity.


Assuntos
Cirurgia Bariátrica , Obesidade Mórbida , Humanos , Lactente , Epigênese Genética , Metilação de DNA , Obesidade/genética , Obesidade/cirurgia , Obesidade Mórbida/genética , Dieta Redutora , Redução de Peso/genética , DNA
14.
Sci Rep ; 12(1): 18877, 2022 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-36344536

RESUMO

Bariatric surgery (BS) is an effective intervention for severe obesity and associated comorbidities. Although several studies have addressed the clinical and metabolic effects of BS, an integrative analysis of the complex body response to surgery is still lacking. We conducted a longitudinal data study with 36 patients with severe obesity who were tested before, 6 and 12 months after restrictive BS for more than one hundred blood biomarkers, including clinical, oxidative stress and metabolic markers, peptide mediators and red blood cell membrane lipids. By using a synthetic data-driven modeling based on principal component and correlation analyses, we provided evidence that, besides the early, well-known glucose metabolism- and weight loss-associated beneficial effects of BS, a tardive, weight-independent increase of the hepatic cholesterol metabolism occurs that is associated with potentially detrimental inflammatory and metabolic effects. Canonical correlation analysis indicated that oxidative stress is the most predictive feature of the BS-induced changes of both glucose and lipids metabolism. Our results show the power of multi-level correlation analysis to uncover the network of biological pathways affected by BS. This approach highlighted potential health risks of restrictive BS that are disregarded with the current practice to use weight loss as surrogate of BS success.


Assuntos
Cirurgia Bariátrica , Obesidade Mórbida , Humanos , Cirurgia Bariátrica/métodos , Redução de Peso/fisiologia , Aumento de Peso , Medição de Risco
15.
Mutat Res ; 718(1-2): 62-7, 2011 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-20971211

RESUMO

Several lines of evidence suggest an association between oxidative DNA-damage repair capacity and cancer risk. In particular, a DNA-glycosylase assay for removal of 8-oxoguanine (8-oxoG) in peripheral blood mononuclear cells (PBMC) has been successfully applied to identify populations with increased risk for lung cancer and squamous cell carcinomas of head and neck. In order to verify whether EBV-transformed lymphoblastoid cell lines (LCL) are a suitable surrogate for PBMC in specific DNA-repair phenotypic assays, a validation trial was conducted. PBMC from 20 healthy subjects were collected and an aliquot was transformed with EBV to obtain LCL. The ability of cell-free extracts from both cell types to incise a 3'-fluorescently labelled duplex oligonucleotide containing a single 8-oxoG (OGG assay) was evaluated. Since this activity is mediated predominantly by OGG1, the OGG1 gene expression was also measured. 8-oxoG DNA-glycosylase activity and OGG1 expression were significantly higher (p<0.0001) in LCL than in PBMC. However, while this assay was shown to be robust and reproducible when used on PBMC (intra-assay CV=8%), a high intra-culture variability was observed with LCL (intra-culture CV=16.8%). Neither differences on OGG1 gene expression nor the cell-cycle distribution seemed to account for this variability. Inter-individual variability of OGG activity in PBMC and LCL was not associated with OGG1 gene expression. We have therefore established a non-radioactive cleavage assay that can be easily applied to measure OGG activity in human PBMC. The use of LCL for DNA-repair genotype-phenotype correlation studies seems to be inappropriate, at least with cell-free based functional assays.


Assuntos
DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Reparo do DNA , Guanina/análogos & derivados , Linfócitos/metabolismo , Linhagem Celular , Transformação Celular Viral , Criopreservação , Expressão Gênica , Estudos de Associação Genética , Guanina/metabolismo , Herpesvirus Humano 4 , Humanos , Técnicas In Vitro
16.
BMC Cancer ; 10: 129, 2010 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-20374648

RESUMO

BACKGROUND: Prostate stem cell antigen (PSCA) is a glycosylphosphatidylinositol (GPI) anchored protein expressed not only in prostate but also in pancreas and bladder cancer as shown by immunohistochemistry and mRNA analysis. It has been targeted by monoclonal antibodies in preclinical animal models and more recently in a clinical trial in prostate cancer patients. The biological role played in tumor growth is presently unknown. In this report we have characterized the contribution of PSCA expression to tumor growth. METHODS: A bladder cell line was engineered to express a doxycycline (dox) regulated shRNA against PSCA. To shed light on the PSCA biological role in tumor growth, microarray analysis was carried out as a function of PSCA expression. Expression of gene set of interest was further analyzed by qPCR RESULTS: Down regulation of the PSCA expression was associated with reduced cell proliferation in vitro and in vivo. Mice bearing subcutaneous tumors showed a reduced tumor growth upon treatment with dox, which effectively induced shRNA against PSCA as revealed by GFP expression. Pathway analysis of deregulated genes suggests a statistical significant association between PSCA downregulation and activation of genes downstream of the IFNalpha/beta receptor. CONCLUSIONS: These experiments established for the first time a correlation between the level of PSCA expression and tumor growth and suggest a role of PSCA in counteracting the natural immune response.


Assuntos
Glicoproteínas de Membrana/biossíntese , Proteínas de Neoplasias/biossíntese , Neoplasias da Bexiga Urinária/patologia , Animais , Antígenos de Neoplasias , Processos de Crescimento Celular/fisiologia , Linhagem Celular Tumoral , Células Clonais , Regulação para Baixo , Doxiciclina/farmacologia , Feminino , Proteínas Ligadas por GPI , Humanos , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/imunologia , Camundongos , Camundongos Nus , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/imunologia , Reação em Cadeia da Polimerase , Interferência de RNA , Transdução de Sinais/imunologia , Transcrição Gênica , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/imunologia , Neoplasias da Bexiga Urinária/metabolismo
17.
Mutagenesis ; 25(6): 569-75, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20817763

RESUMO

Risk factors for gastric cancer (GC) include inter-individual variability in the inflammatory response to Helicobacter pylori infection, in the ability of detoxifying DNA reactive species and repairing DNA damage generated by oxidative stress and dietary carcinogens. To evaluate the association between polymorphic DNA repair genes and GC risk, a case-control study including 314 histologically confirmed GC patients and 548 healthy controls was conducted in a GC high-risk area in Tuscany, Italy. Polymorphic variants of base excision repair (APE1-D148E, XRCC1-R194W, XRCC1-R399Q and OGG1-S326C), nucleotide excision repair (XPC-PAT, XPA-23G>A, ERCC1-19007T>C and XPD-L751Q), recombination (XRCC3-T241M) and alkylation damage reversal (MGMT-L84F) were tested for their potential role in the development of GC by using logistic regression models. The same population was also characterised for GSTT1 and GSTM1 variant alleles to search for possible functional interactions between metabolic and DNA repair genotypes by two-way interactions using multivariate logistic models. No significant association between any single DNA repair genotype and GC risk was detected with a borderline association with the XPC-PAT homozygous genotype [odds ratio (OR) =1.42; 95% confidence interval (CI) 0.94-2.17]. Gene-gene interaction analysis revealed combinations of unfavourable genotypes involving either multiple DNA repair polymorphisms or DNA repair and GST-specific genotypes. The combination of the XPC-PAT and the XPA variant alleles significantly increased GC risk (OR=2.15; 95% CI 1.17-3.93, P=0.0092). A significant interaction was also found between the APE1 wild-type genotype and either the single GSTT1 (OR=4.90; 95% CI 2.38-10.11, P=0.0079) or double GSTM1-GSTT1 null (OR=7.84; 95% CI 3.19-19.22, P=0.0169) genotypes or the XPA-mutant allele (OR=3.56; 95% CI 1.53-8.25, P=0.0012). These findings indicate that a complex interaction between host factors such as oxidative stress, antioxidant capacity and efficiency of multiple DNA repair pathways underlies the inter-individual variability in GC risk.


Assuntos
Adenocarcinoma/genética , Reparo do DNA/genética , Metabolismo/genética , Polimorfismo Genético , Neoplasias Gástricas/genética , Idoso , Estudos de Casos e Controles , Enzimas Reparadoras do DNA/genética , Feminino , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético/fisiologia
18.
Mutat Res ; 670(1-2): 79-87, 2009 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-19635489

RESUMO

DNA repair polymerase beta (Pol beta) gene variants are frequently associated with tumor tissues. In this study a search for Pol beta mutants and splice variants was conducted in matched normal and tumor gastric tissues and blood samples from healthy donors. No tumor associated mutations were found while a variety of alternative Pol beta splicing variants were detected with high frequency in all the specimens analysed. Quantitative PCR of the Pol beta variant lacking exon 2 (Ex2Delta) and the isoforms with exon 11 skipping allowed to clarify that these variants are not tumor- neither tissue-specific and their levels vary greatly among different individuals. The most frequent Ex2Delta variant was further characterized. We clearly demonstrated that this variant does not encode protein, as detected by both western blotting and immunofluorescence analysis of human AGS cells expressing HA-tagged Ex2Delta. The lack of translation was confirmed by comparing the DNA gap-filling capacity and alkylation sensitivity of wild type and Pol beta null murine fibroblasts expressing the human Ex2Delta variant. We showed that the Ex2Delta transcript is polyadenylated and its half-life is significantly longer than that of the wild type mRNA as inferred by treating AGS cells with actinomycin D. Moreover, we found that it localizes to polyribosomes suggesting a role as post-transcriptional regulator. This study identifies a new type of DNA repair variants that do not give rise to functional proteins but to non-coding RNAs that could either modulate target mRNAs or represent unproductive splicing events.


Assuntos
DNA Polimerase beta/genética , Éxons , Isoformas de Proteínas , RNA não Traduzido , Neoplasias Gástricas/genética , Processamento Alternativo , Animais , Estudos de Casos e Controles , Linhagem Celular , Linhagem Celular Tumoral , Reparo do DNA , Humanos , Camundongos , Isoformas de Proteínas/genética , Splicing de RNA , Estômago , Transfecção
19.
Nucleic Acids Res ; 35(5): 1569-77, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17289756

RESUMO

It has been hypothesized that a replication associated repair pathway operates on base damage and single strand breaks (SSB) at replication forks. In this study, we present the isolation from the nuclei of human cycling cells of a multiprotein complex containing most of the essential components of base excision repair (BER)/SSBR, including APE1, UNG2, XRCC1 and POLbeta, DNA PK, replicative POLalpha, delta and epsilon, DNA ligase 1 and cell cycle regulatory protein cyclin A. Co-immunoprecipitation revealed that in this complex DNA repair proteins are physically associated to cyclin A and to DNA replication proteins including MCM7. This complex is endowed with DNA polymerase and protein kinase activity and is able to perform BER of uracil and AP sites. This finding suggests that a preassembled DNA repair machinery is constitutively active in cycling cells and is ready to be recruited at base damage and breaks occurring at replication forks.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Reparo do DNA , Replicação do DNA , Animais , Proteínas de Ciclo Celular/isolamento & purificação , Ciclina A/isolamento & purificação , Ciclina A/metabolismo , Enzimas Reparadoras do DNA/isolamento & purificação , Proteínas de Ligação a DNA/isolamento & purificação , Proteínas de Ligação a DNA/metabolismo , DNA Polimerase Dirigida por DNA/isolamento & purificação , DNA Polimerase Dirigida por DNA/metabolismo , Células HeLa , Humanos , Imunoprecipitação , Camundongos , Componente 7 do Complexo de Manutenção de Minicromossomo , Proteínas Nucleares/isolamento & purificação , Proteínas Nucleares/metabolismo
20.
Ann Ist Super Sanita ; 55(4): 323-329, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31850858

RESUMO

Climate changes affect social and environmental health determinants such as clean air, ecosystems health, safe drinking water and safe sufficient food. Globally, people at greatest risk of adverse health effects associated with climate change include children, the elderly and other vulnerable groups. Temperature-related death and illness, extreme events, polluted or stressed ecosystems represent relevant issues raising concern for both health and economic consequences. The aim of the Symposium "Health and Climate Change" (Istituto Superiore di Sanità, Rome 3-5 December 2018) was to promote an inter-sectoral and multidisciplinary approach to estimate and prevent climate change-related events as well as to call the authorities to put in place measures to reduce adverse health effects. At the end of the Symposium the Rome International Charter on Health and Climate Change was presented. It includes a series of actions and recommendations, discussed and shared by all the participants, intended to inform policy makers and all the stakeholders involved in the management of climate changes.


Assuntos
Mudança Climática , Congressos como Assunto , Saúde Ambiental , Animais , Saúde da Criança , Doenças Transmissíveis Emergentes , Surtos de Doenças , Saúde Ambiental/legislação & jurisprudência , Abastecimento de Alimentos/normas , Humanos , Cooperação Internacional , Itália , Saúde Mental , Publicações , Determinantes Sociais da Saúde , Populações Vulneráveis , Abastecimento de Água/normas , Zoonoses
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