Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.047
Filtrar
1.
Molecules ; 26(5)2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33652850

RESUMO

Cystic fibrosis (CF) is a genetic disease caused by mutations that impair the function of the CFTR chloride channel. The most frequent mutation, F508del, causes misfolding and premature degradation of CFTR protein. This defect can be overcome with pharmacological agents named "correctors". So far, at least three different classes of correctors have been identified based on the additive/synergistic effects that are obtained when compounds of different classes are combined together. The development of class 2 correctors has lagged behind that of compounds belonging to the other classes. It was shown that the efficacy of the prototypical class 2 corrector, the bithiazole corr-4a, could be improved by generating conformationally-locked bithiazoles. In the present study, we investigated the effect of tricyclic pyrrolothiazoles as analogues of constrained bithiazoles. Thirty-five compounds were tested using the functional assay based on the halide-sensitive yellow fluorescent protein (HS-YFP) that measured CFTR activity. One compound, having a six atom carbocyle central ring in the tricyclic pyrrolothiazole system and bearing a pivalamide group at the thiazole moiety and a 5-chloro-2-methoxyphenyl carboxamide at the pyrrole ring, significantly increased F508del-CFTR activity. This compound could lead to the synthesis of a novel class of CFTR correctors.


Assuntos
Benzodioxóis/farmacologia , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Fibrose Cística/tratamento farmacológico , Proteínas Mutantes/genética , Aminoimidazol Carboxamida/química , Benzodioxóis/química , Fibrose Cística/genética , Fibrose Cística/patologia , Regulador de Condutância Transmembrana em Fibrose Cística/efeitos dos fármacos , Humanos , Mutação/efeitos dos fármacos , Mutação/genética , Dobramento de Proteína/efeitos dos fármacos , Tiazóis/química
2.
Nat Methods ; 18(3): 249-252, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33619392

RESUMO

RNA structure heterogeneity is a major challenge when querying RNA structures with chemical probing. We introduce DRACO, an algorithm for the deconvolution of coexisting RNA conformations from mutational profiling experiments. Analysis of the SARS-CoV-2 genome using dimethyl sulfate mutational profiling with sequencing (DMS-MaPseq) and DRACO, identifies multiple regions that fold into two mutually exclusive conformations, including a conserved structural switch in the 3' untranslated region. This work may open the way to dissecting the heterogeneity of the RNA structurome.


Assuntos
Algoritmos , Genoma Viral/genética , Conformação de Ácido Nucleico , RNA Viral/química , /genética , Regiões 3' não Traduzidas/genética , Humanos , Mutação/efeitos dos fármacos , Mutação/genética , RNA Viral/genética , Ésteres do Ácido Sulfúrico/farmacologia
3.
AIDS ; 35(2): 227-234, 2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33394670

RESUMO

OBJECTIVES: HIV-1 pretreatment drug resistance (PDR) is a global concern. Our aim was to evaluate high-throughput sequencing (HTS) for HIV-1 resistance testing and describe PDR in Sweden, where 75% of diagnosed individuals are foreign-born. DESIGN: Cross-sectional study. METHODS: Individuals entering HIV-1 care in Sweden 2017 to March 2019 (n = 400) were included if a viremic sample was available (n = 220). HTS was performed using an in-house assay. Drug resistance mutations (DRMs) (based on Stanford HIV DB vs. 8.7) at levels 1-5%, 5-19% and at least 20% of the viral population were described. Results from HTS and routine Sanger sequencing were compared. RESULTS: HTS was successful in 88% of patients, 92% when viral load was at least 1000 copies/ml. DRMs at any level in protease and/or reverse transcriptase were detected in 95 individuals (49%), whereas DRMs at least 20% in 35 (18%) individuals. DRMs at least 20% correlated well to findings in routine Sanger sequencing. Protease/reverse transcriptase (PR/RT) DRMs at least 20% were predicted by treatment exposure; adjusted OR 9.28 (95% CI 2.24-38.43; P = 0.002) and origin in Asia; adjusted OR 20.65 (95% CI 1.66-256.24; P = 0.02). Nonnucleoside reverse transcriptase inhibitor (NNRTI) DRMs at least 20% were common (16%) and over-represented in individuals originating from sub-Saharan Africa or Asia. Low-level integrase strand transfer inhibitor (INSTI) DRMs less than 20% were detected in 15 individuals (8%) with no association with INSTI exposure. CONCLUSION: Our HTS can efficiently detect PDR and findings of DRMs at least 20% compare well to routine Sanger sequencing. The high prevalence of PDR was because of NNRTI DRMs and associated with migration from areas with emerging PDR.


Assuntos
Fármacos Anti-HIV , Farmacorresistência Viral , Infecções por HIV , HIV-1 , África ao Sul do Saara , Fármacos Anti-HIV/uso terapêutico , Ásia , Estudos Transversais , Genótipo , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , HIV-1/efeitos dos fármacos , HIV-1/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Mutação/efeitos dos fármacos , Prevalência , Suécia/epidemiologia
4.
Biochim Biophys Acta Gen Subj ; 1865(1): 129736, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32956754

RESUMO

BACKGROUND: The introduction of targeted therapies for the treatment of BRAF-mutant melanomas have improved survival rates in a significant proportion of patients. Nonetheless, the emergence of resistance to treatment remains inevitable in most patients. SCOPE OF REVIEW: Here, we review known and emerging molecular mechanisms that underlay the development of resistance to MAPK inhibition in melanoma cells and the potential strategies to overcome these mechanisms. MAJOR CONCLUSIONS: Multiple genetic and non-genetic mechanisms contribute to treatment failure, commonly leading to the reactivation of the MAPK pathway. A variety of resistance mechanisms are enabled by the underlying heterogeneity and plasticity of melanoma cells. Moreover, it has become apparent that resistance to targeted therapy is underpinned by early functional adaptations involving the rewiring of cell states and metabolic pathways. GENERAL SIGNIFICANCE: The evidence presented suggest that the use of a combinatorial treatment approach would delay the emergence of resistance and improve patient outcomes.


Assuntos
Resistencia a Medicamentos Antineoplásicos , Melanoma/tratamento farmacológico , Melanoma/genética , Proteínas Proto-Oncogênicas B-raf/genética , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Melanoma/metabolismo , Terapia de Alvo Molecular , Mutação/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/metabolismo
5.
PLoS One ; 15(12): e0243746, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33315900

RESUMO

Niemann-Pick disease type C is a rare, fatal neurodegenerative disorder characterized by massive intracellular accumulation of cholesterol. In most cases, loss-of-function mutations in the NPC1 gene that encodes lysosomal cholesterol transporter NPC1 are responsible for the disease, and more than half of the mutations are considered to interfere with the biogenesis or folding of the protein. We previously identified a series of oxysterol derivatives and phenanthridine-6-one derivatives as pharmacological chaperones, i.e., small molecules that can rescue folding-defective phenotypes of mutated NPC1, opening up an avenue to develop chaperone therapy for Niemann-Pick disease type C. Here, we present an improved image-based screen for NPC1 chaperones and we describe its application for drug-repurposing screening. We identified some azole antifungals, including itraconazole and posaconazole, and a kinase inhibitor, lapatinib, as probable pharmacological chaperones. A photo-crosslinking study confirmed direct binding of itraconazole to a representative folding-defective mutant protein, NPC1-I1061T. Competitive photo-crosslinking experiments suggested that oxysterol-based chaperones and itraconazole share the same or adjacent binding site(s), and the sensitivity of the crosslinking to P691S mutation in the sterol-sensing domain supports the hypothesis that their binding sites are located near this domain. Although the azoles were less effective in reducing cholesterol accumulation than the oxysterol-derived chaperones or an HDAC inhibitor, LBH-589, our findings should offer new starting points for medicinal chemistry efforts to develop better pharmacological chaperones for NPC1.


Assuntos
Descoberta de Drogas/métodos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Doença de Niemann-Pick Tipo C/tratamento farmacológico , Dobramento de Proteína/efeitos dos fármacos , Reposicionamento de Medicamentos/métodos , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/análise , Mutação/efeitos dos fármacos , Doença de Niemann-Pick Tipo C/genética , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia
6.
Korean J Parasitol ; 58(5): 543-550, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33202506

RESUMO

Mosquitoes are globally distributed and important vectors for the transmission of many human diseases. Mosquito control is a difficult task and the cost of preventing mosquito-borne diseases is much lower than that for curing the associated diseases. Thus, chemical control remains the most effective tool for mosquito. Due to the long-term intensive use of insecticides to control mosquito vectors, resistance to most chemical insecticides has been reported. This study aimed to investigate the relationship between insecticide resistance and target site mutation of L1014 kdr and G119 ace alleles in 5 species/species group of mosquitoes (Aedes vexans, Ae. albopictus, Anopheles spp., Culex pipiens complex, and Cx. tritaeniorhynchus) obtained from 6 collection sites. For Anopheles spp., the proportion of mosquitoes with mutated alleles in L1014 was 88.4%, homozygous resistant genotypes were observed in 46.7%, and heterozygous resistant genotypes were observed in 41.8%. For the Cx. pipiens complex and Cx. tritaeniorhynchus species, homozygous resistant genotypes were found in 25.9% and 9.8%, respectively. However, target site mutation of L1014 in the Ae. vexans nipponii and Ae. albopictus species was not observed. Anopheles spp., Cx. pipiens complex, and Cx. tritaeniorhynchus mosquitoes were resistant to deltamethrin and chlorpyriphos, whereas Ae. vexans nipponii and Ae. albopictus were clearly susceptible. We also found a correlation between the resistance phenotype and the presence of the L1014 kdr and G119 ace mutations only in the Anopheles spp. population. In this study, we suggest that insecticide resistance poses a growing threat and resistance management must be integrated into all mosquito control programs.


Assuntos
Alelos , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Controle de Mosquitos , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/genética , Mutação/efeitos dos fármacos , Animais , Monitoramento Ambiental , Humanos , Mosquitos Vetores/classificação , República da Coreia , Doenças Transmitidas por Vetores/prevenção & controle , Doenças Transmitidas por Vetores/transmissão
7.
Nat Commun ; 11(1): 5374, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33097713

RESUMO

The emergence of resistance to azithromycin complicates treatment of Neisseria gonorrhoeae, the etiologic agent of gonorrhea. Substantial azithromycin resistance remains unexplained after accounting for known resistance mutations. Bacterial genome-wide association studies (GWAS) can identify novel resistance genes but must control for genetic confounders while maintaining power. Here, we show that compared to single-locus GWAS, conducting GWAS conditioned on known resistance mutations reduces the number of false positives and identifies a G70D mutation in the RplD 50S ribosomal protein L4 as significantly associated with increased azithromycin resistance (p-value = 1.08 × 10-11). We experimentally confirm our GWAS results and demonstrate that RplD G70D and other macrolide binding site mutations are prevalent (present in 5.42% of 4850 isolates) and widespread (identified in 21/65 countries across two decades). Overall, our findings demonstrate the utility of conditional associations for improving the performance of microbial GWAS and advance our understanding of the genetic basis of macrolide resistance.


Assuntos
Farmacorresistência Bacteriana/genética , Genoma Bacteriano , Estudo de Associação Genômica Ampla , Neisseria gonorrhoeae/efeitos dos fármacos , Neisseria gonorrhoeae/genética , Antibacterianos/farmacologia , Azitromicina/farmacologia , Sítios de Ligação/genética , Gonorreia/tratamento farmacológico , Gonorreia/microbiologia , Humanos , Macrolídeos/farmacologia , Testes de Sensibilidade Microbiana , Mutação/efeitos dos fármacos , RNA Ribossômico 23S/genética
8.
Nat Commun ; 11(1): 5463, 2020 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-33122628

RESUMO

Metastatic melanoma remains an incurable disease for many patients due to the limited success of targeted and immunotherapies. BRAF and MEK inhibitors reduce metastatic burden for patients with melanomas harboring BRAF mutations; however, most eventually relapse due to acquired resistance. Here, we demonstrate that ABL1/2 kinase activities and/or expression are potentiated in cell lines and patient samples following resistance, and ABL1/2 drive BRAF and BRAF/MEK inhibitor resistance by inducing reactivation of MEK/ERK/MYC signaling. Silencing/inhibiting ABL1/2 blocks pathway reactivation, and resensitizes resistant cells to BRAF/MEK inhibitors, whereas expression of constitutively active ABL1/2 is sufficient to promote resistance. Significantly, nilotinib (2nd generation ABL1/2 inhibitor) reverses resistance, in vivo, causing prolonged regression of resistant tumors, and also, prevents BRAFi/MEKi resistance from developing in the first place. These data indicate that repurposing the FDA-approved leukemia drug, nilotinib, may be effective for prolonging survival for patients harboring BRAF-mutant melanomas.


Assuntos
Resistencia a Medicamentos Antineoplásicos/genética , Melanoma/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Linhagem Celular Tumoral , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Melanoma/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/efeitos dos fármacos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Mutação/efeitos dos fármacos , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-abl/genética , Proteínas Proto-Oncogênicas c-abl/metabolismo
9.
Life Sci ; 261: 118434, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32941897

RESUMO

Defective DNA repair is one of the most important features of tumors. BRCA1/2 participates in homologous recombination repair as a key tumor suppressor gene. BRCA1/2 mutation is an important biomarker for predicting the sensitivity of platinum salts and Poly (ADP-ribose) polymerase (PARP) inhibitors in breast cancer, ovarian cancer, and other cancers. However, epigenetic modifications and other mutations in homologous recombination repair (HRR) genes can also cause homologous recombination deficiency (HRD). Patients with no BRCA1/2 mutations, but bearing similar molecular phenotypes (BRCAness) can still obtain clinical benefits from treatment with platinum salts or PARP inhibitors. Therefore, an accurate assessment of HRD is essential for the formulation of personalized treatments. However, methods to identify HRD in tumors vary and are controversial. Currently, genomic scar assays have been used in multiple clinical trials to assess patient clinical benefit. This review summarizes the therapeutic effects of platinum salts and PARP inhibitors in breast and ovarian cancer, clarifies the predictive value of genomic scar assays in evaluating the clinical benefit of different patient groups and treatment options, and proposes the limitations and optimization of current HRD scoring methods. Using and optimizing genomic scar assays can help to accurately screen the population with the most benefit, expand the scope of drug application, and make the most suitable clinical decision based on individual differences.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/genética , Platina/uso terapêutico , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Animais , Antineoplásicos/farmacologia , Epigênese Genética/efeitos dos fármacos , Genômica , Humanos , Mutação/efeitos dos fármacos , Platina/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Reparo de DNA por Recombinação/efeitos dos fármacos
10.
J Mol Biol ; 432(21): 5843-5847, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-32920049

RESUMO

SARS-CoV-2 uses -1 programmed ribosomal frameshifting (-1 PRF) to control expression of key viral proteins. Because modulating -1 PRF can attenuate the virus, ligands binding to the RNA pseudoknot that stimulates -1 PRF may have therapeutic potential. Mutations in the pseudoknot have occurred during the pandemic, but how they affect -1 PRF efficiency and ligand activity is unknown. Studying a panel of six mutations in key regions of the pseudoknot, we found that most did not change -1 PRF levels, even when base-pairing was disrupted, but one led to a striking 3-fold decrease, suggesting SARS-CoV-2 may be less sensitive to -1 PRF modulation than expected. Examining the effects of a small-molecule -1 PRF inhibitor active against SARS-CoV-2, it had a similar effect on all mutants tested, regardless of basal -1 PRF efficiency, indicating that anti-frameshifting activity can be resistant to natural pseudoknot mutations. These results have important implications for therapeutic strategies targeting SARS-CoV-2 through modulation of -1 PRF.


Assuntos
Antivirais/farmacologia , Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Mudança da Fase de Leitura do Gene Ribossômico/efeitos dos fármacos , Regulação Viral da Expressão Gênica/efeitos dos fármacos , Pneumonia Viral/tratamento farmacológico , Bibliotecas de Moléculas Pequenas/farmacologia , Antivirais/química , Betacoronavirus/genética , Infecções por Coronavirus/virologia , Humanos , Ligantes , Mutação/efeitos dos fármacos , Pandemias , Pneumonia Viral/virologia , RNA Mensageiro/genética , RNA Viral/genética , Bibliotecas de Moléculas Pequenas/química , Proteínas Virais/genética
11.
Anesthesiology ; 133(4): 839-851, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32773682

RESUMO

BACKGROUND: General anesthetics influence mitochondrial homeostasis, placing individuals with mitochondrial disorders and possibly carriers of recessive mitochondrial mutations at increased risk of perioperative complications. In Drosophila, mutations in the ND23 subunit of complex I of the mitochondrial electron transport chain-analogous to mammalian NDUFS8-replicate key characteristics of Leigh syndrome, an inherited mitochondrial disorder. The authors used the ND23 mutant for testing the hypothesis that anesthetics have toxic potential in carriers of mitochondrial mutations. METHODS: The authors exposed wild-type flies and ND23 mutant flies to behaviorally equivalent doses of isoflurane or sevoflurane in 5%, 21%, or 75% oxygen. The authors used percent mortality (mean ± SD, n ≥ 3) at 24 h after exposure as a readout of toxicity and changes in gene expression to investigate toxicity mechanisms. RESULTS: Exposure of 10- to 13-day-old male ND23 flies to isoflurane in 5%, 21%, or 75% oxygen resulted in 16.0 ± 14.9% (n = 10), 48.2 ± 16.1% (n = 9), and 99.2 ± 2.0% (n = 10) mortality, respectively. Comparable mortality was observed in females. In contrast, under the same conditions, mortality was less than 5% for all male and female groups exposed to sevoflurane, except 10- to 13-day-old male ND23 flies with 9.6 ± 8.9% (n = 16) mortality. The mortality of 10- to 13-day-old ND23 flies exposed to isoflurane was rescued by neuron- or glia-specific expression of wild-type ND23. Isoflurane and sevoflurane differentially affected expression of antioxidant genes in 10- to 13-day-old ND23 flies. ND23 flies had elevated mortality from paraquat-induced oxidative stress compared with wild-type flies. The mortality of heterozygous ND23 flies exposed to isoflurane in 75% oxygen increased with age, resulting in 54.0 ± 19.6% (n = 4) mortality at 33 to 39 days old, and the percent mortality varied in different genetic backgrounds. CONCLUSIONS: Mutations in the mitochondrial complex I subunit ND23 increase susceptibility to isoflurane-induced toxicity and to oxidative stress in Drosophila. Asymptomatic flies that carry ND23 mutations are sensitized to hyperoxic isoflurane toxicity by age and genetic background.


Assuntos
Anestésicos Inalatórios/toxicidade , Complexo I de Transporte de Elétrons/genética , Isoflurano/toxicidade , Mitocôndrias/genética , Mutação/genética , Envelhecimento/efeitos dos fármacos , Envelhecimento/genética , Envelhecimento/patologia , Animais , Animais Geneticamente Modificados , Drosophila , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Mutação/efeitos dos fármacos , Sevoflurano/toxicidade
13.
Nat Commun ; 11(1): 3617, 2020 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-32680998

RESUMO

Multiple myeloma (MM) progression is characterized by the seeding of cancer cells in different anatomic sites. To characterize this evolutionary process, we interrogated, by whole genome sequencing, 25 samples collected at autopsy from 4 patients with relapsed MM and an additional set of 125 whole exomes collected from 51 patients. Mutational signatures analysis showed how cytotoxic agents introduce hundreds of unique mutations in each surviving cancer cell, detectable by bulk sequencing only in cases of clonal expansion of a single cancer cell bearing the mutational signature. Thus, a unique, single-cell genomic barcode can link chemotherapy exposure to a discrete time window in a patient's life. We leveraged this concept to show that MM systemic seeding is accelerated at relapse and appears to be driven by the survival and subsequent expansion of a single myeloma cell following treatment with high-dose melphalan therapy and autologous stem cell transplant.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Evolução Clonal/efeitos dos fármacos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Mieloma Múltiplo/patologia , Recidiva Local de Neoplasia/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Progressão da Doença , Relação Dose-Resposta a Droga , Humanos , Masculino , Melfalan/administração & dosagem , Melfalan/efeitos adversos , Pessoa de Meia-Idade , Mieloma Múltiplo/diagnóstico por imagem , Mieloma Múltiplo/genética , Mieloma Múltiplo/terapia , Mutação/efeitos dos fármacos , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Recidiva Local de Neoplasia/diagnóstico por imagem , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/terapia , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Análise de Célula Única , Análise Espaço-Temporal , Transplante Autólogo/efeitos adversos , Sequenciamento Completo do Genoma
14.
Mutat Res ; 853: 503195, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32522347

RESUMO

Recent years have witnessed an expansion of mutagenesis research focusing on experimentally modeled genome-scale mutational signatures of carcinogens and of endogenous processes. Experimental mutational signatures can explain etiologic links to patterns found in human tumors that may be linked to same exposures, and can serve as biomarkers of exposure history and may even provide insights on causality. A number of innovative exposure models have been employed and reported, based on cells cultured in monolayers or in 3-D, on organoids, induced pluripotent stem cells, non-mammalian organisms, microorganisms and rodent bioassays. Here we discuss some of the latest developments and pros and cons of these experimental systems used in mutational signature analysis. Integrative designs that bring together multiple exposure systems (in vitro, in vivo and in silico pan-cancer data mining) started emerging as powerful tools to identify robust mutational signatures of the tested cancer risk agents. We further propose that devising a new generation of cell-based models is warranted to streamline systematic testing of carcinogen effects on the cell genomes, while seeking to increasingly supplant animal with non-animal systems to address relevant ethical issues and accentuate the 3R principles. We conclude that the knowledge accumulating from the growing body of signature modelling investigations has considerable power to advance cancer etiology studies and to support cancer prevention efforts through streamlined characterization of cancer-causing agents and the recognition of their specific effects.


Assuntos
Carcinógenos/toxicidade , Mutagênese/efeitos dos fármacos , Mutação/efeitos dos fármacos , Neoplasias/induzido quimicamente , Animais , Análise Mutacional de DNA/métodos , Genoma Humano/efeitos dos fármacos , Genoma Humano/genética , Humanos , Mutagênese/genética , Mutação/genética
15.
Mutat Res ; 853: 503189, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32522351

RESUMO

Age is an important factor in the evaluation of chemical toxicology. Chemical carcinogenic compounds can induce genomic mutations. However, few studies have been conducted on the association between genomic mutation frequency, such as microsatellite instability (MSI), and the age of mice treated with a nitrosourea mutagen. In the current work, we treated young (6 weeks) and old (10 months) mice with N-methyl-N-nitrosourea (MNU) for 4 months; the MSI frequency was then measured using polymerase chain reaction (PCR) and short tandem repeat (STR) scanning. The percentage of animals with MSI in the old group was significantly higher than that in the young group (100% and 75%). The frequency of MSI events was significantly different between the two groups as well (15.8% for old and 9.4% for young). The ratio of MSI loci displayed no obvious difference between the two groups. In addition, a few loci, including D15Mit5 and D8Mit14 exhibited the highest frequency of MSI events. Since specific loci showed increased MSI in the present study and a higher frequency in previous studies, these loci could be regarded as "hot spot". These results suggested that old mice would be more susceptible to this mutagen, and prone to accrue MSI. The hot spot microsatellite loci are potentially useful markers for genomic instability analysis.


Assuntos
Metilnitrosoureia/farmacologia , Instabilidade de Microssatélites/efeitos dos fármacos , Animais , Carcinógenos/farmacologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Repetições de Microssatélites/efeitos dos fármacos , Mutagênicos/farmacologia , Mutação/efeitos dos fármacos
16.
PLoS Negl Trop Dis ; 14(6): e0008350, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32569337

RESUMO

BACKGROUND: The arboviral vector Aedes albopictus became established on all continents except Antarctica in the past 50 years. A consequence of its rapid global invasion is the transmission of diseases previously confined to the tropics and subtropics occurring in temperate regions of the world, including the re-emergence of chikungunya and dengue in Europe. Application of pyrethroids is among the most widely-used interventions for vector control, especially in the presence of an arboviral outbreak. Studies are emerging that reveal phenotypic resistance and monitor mutations at the target site, the para sodium channel gene, primarily on a local scale. METHODS: A total of 512 Ae. albopictus mosquitoes from twelve geographic sites, including those from the native home range and invaded areas, were sampled between 2011 and 2018, and were analyzed at five codons of the para sodium channel gene with mutations predictive of resistance phenotype. Additionally, to test for the origin of unique kdr mutations in Mexico, we analyzed the genetic connectivity of southern Mexico mosquitoes with mosquitoes from home range, the Reunion Island, America and Europe. RESULTS: We detected mutations at all tested positions of the para sodium channel gene, with heterozygotes predominating and rare instance of double mutants. We observed an increase in the distribution and frequency of F1534C/L/S mutations in the ancestral China population and populations in the Mediterranean Greece, the appearance of the V1016G/I mutations as early as 2011 in Italy and mutations at position 410 and 989 in Mexico. The analyses of the distribution pattern of kdr alleles and haplotype network analyses showed evidence for multiple origins of all kdr mutations. CONCLUSIONS: Here we provide the most-up-to-date survey on the geographic and temporal distribution of pyrethroid-predictive mutations in Ae. albopictus by combining kdr genotyping on current and historical samples with published data. While we confirm low levels of pyrethroid resistance in most analyzed samples, we find increasing frequencies of F1534C/S and V1016G in China and Greece or Italy, respectively. The observed patterns of kdr allele distribution support the hypothesis that on site emergence of resistance has contributed more than spread of resistance through mosquito migration/invasions to the current widespread of kdr alleles, emphasizing the importance of local surveillance programs and resistance management.


Assuntos
Aedes/efeitos dos fármacos , Aedes/genética , Resistência a Inseticidas/genética , Piretrinas/farmacologia , Alelos , Animais , Arbovirus , Vetores de Doenças , Variação Genética , Genótipo , Haplótipos , Proteínas de Insetos/genética , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mutação/efeitos dos fármacos , Canais de Sódio/genética
17.
Nat Med ; 26(7): 1063-1069, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32483361

RESUMO

The mucosal epithelium is a common target of damage by chronic bacterial infections and the accompanying toxins, and most cancers originate from this tissue. We investigated whether colibactin, a potent genotoxin1 associated with certain strains of Escherichia coli2, creates a specific DNA-damage signature in infected human colorectal cells. Notably, the genomic contexts of colibactin-induced DNA double-strand breaks were enriched for an AT-rich hexameric sequence motif, associated with distinct DNA-shape characteristics. A survey of somatic mutations at colibactin target sites of several thousand cancer genomes revealed notable enrichment of this motif in colorectal cancers. Moreover, the exact double-strand-break loci corresponded with mutational hot spots in cancer genomes, reminiscent of a trinucleotide signature previously identified in healthy colorectal epithelial cells3. The present study provides evidence for the etiological role of colibactin in human cancer.


Assuntos
Neoplasias Colorretais/genética , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Peptídeos/farmacologia , Policetídeos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Neoplasias Colorretais/microbiologia , Neoplasias Colorretais/patologia , Células Epiteliais/efeitos dos fármacos , Escherichia coli/patogenicidade , Humanos , Mutação/efeitos dos fármacos , Motivos de Nucleotídeos/efeitos dos fármacos
18.
ACS Comb Sci ; 22(6): 297-305, 2020 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-32402186

RESUMO

A new coronavirus (CoV) caused a pandemic named COVID-19, which has become a global health care emergency in the present time. The virus is referred to as SARS-CoV-2 (severe acute respiratory syndrome-coronavirus-2) and has a genome similar (∼82%) to that of the previously known SARS-CoV (SARS coronavirus). An attractive therapeutic target for CoVs is the main protease (Mpro) or 3-chymotrypsin-like cysteine protease (3CLpro), as this enzyme plays a key role in polyprotein processing and is active in a dimeric form. Further, Mpro is highly conserved among various CoVs, and a mutation in Mpro is often lethal to the virus. Thus, drugs targeting the Mpro enzyme significantly reduce the risk of mutation-mediated drug resistance and display broad-spectrum antiviral activity. The combinatorial design of peptide-based inhibitors targeting the dimerization of SARS-CoV Mpro represents a potential therapeutic strategy. In this regard, we have compiled the literature reports highlighting the effect of mutations and N-terminal deletion of residues of SARS-CoV Mpro on its dimerization and, thus, catalytic activity. We believe that the present review will stimulate research in this less explored yet quite significant area. The effect of the COVID-19 epidemic and the possibility of future CoV outbreaks strongly emphasize the urgent need for the design and development of potent antiviral agents against CoV infections.


Assuntos
Betacoronavirus/enzimologia , Infecções por Coronavirus/tratamento farmacológico , Cisteína Endopeptidases/metabolismo , Pneumonia Viral/tratamento farmacológico , Inibidores de Proteases/farmacologia , Multimerização Proteica/efeitos dos fármacos , Proteínas não Estruturais Virais/metabolismo , Antivirais/farmacologia , Betacoronavirus/química , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/genética , Infecções por Coronavirus/virologia , Cisteína Endopeptidases/química , Cisteína Endopeptidases/genética , Descoberta de Drogas , Humanos , Modelos Moleculares , Terapia de Alvo Molecular , Mutação/efeitos dos fármacos , Pandemias , Peptídeos/farmacologia , Pneumonia Viral/virologia , Conformação Proteica/efeitos dos fármacos , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/genética
19.
Nat Rev Cancer ; 20(7): 365-382, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32415283

RESUMO

Haematopoiesis is governed by haematopoietic stem cells (HSCs) that produce all lineages of blood and immune cells. The maintenance of blood homeostasis requires a dynamic response of HSCs to stress, and dysregulation of these adaptive-response mechanisms underlies the development of myeloid leukaemia. Leukaemogenesis often occurs in a stepwise manner, with genetic and epigenetic changes accumulating in pre-leukaemic HSCs prior to the emergence of leukaemic stem cells (LSCs) and the development of acute myeloid leukaemia. Clinical data have revealed the existence of age-related clonal haematopoiesis, or the asymptomatic clonal expansion of mutated blood cells in the elderly, and this phenomenon is connected to susceptibility to leukaemic transformation. Here we describe how selection for specific mutations that increase HSC competitive fitness, in conjunction with additional endogenous and environmental changes, drives leukaemic transformation. We review the ways in which LSCs take advantage of normal HSC properties to promote survival and expansion, thus underlying disease recurrence and resistance to conventional therapies, and we detail our current understanding of leukaemic 'stemness' regulation. Overall, we link the cellular and molecular mechanisms regulating HSC behaviour with the functional dysregulation of these mechanisms in myeloid leukaemia and discuss opportunities for targeting LSC-specific mechanisms for the prevention or cure of malignant diseases.


Assuntos
Carcinogênese/genética , Hematopoese/fisiologia , Células-Tronco Hematopoéticas/fisiologia , Leucemia Mieloide Aguda/fisiopatologia , Antineoplásicos/farmacologia , Carcinogênese/efeitos dos fármacos , Carcinogênese/patologia , Interação Gene-Ambiente , Instabilidade Genômica/efeitos dos fármacos , Instabilidade Genômica/fisiologia , Hematopoese/genética , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/patologia , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Mutação/efeitos dos fármacos , Mutação/genética , Mutação/fisiologia , Nicho de Células-Tronco/efeitos dos fármacos , Nicho de Células-Tronco/fisiologia , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/fisiologia
20.
Proc Natl Acad Sci U S A ; 117(23): 12931-12942, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32457148

RESUMO

Retinal disease and loss of vision can result from any disruption of the complex pathways controlling retinal development and homeostasis. Forward genetics provides an excellent tool to find, in an unbiased manner, genes that are essential to these processes. Using N-ethyl-N-nitrosourea mutagenesis in mice in combination with a screening protocol using optical coherence tomography (OCT) and automated meiotic mapping, we identified 11 mutations presumably causative of retinal phenotypes in genes previously known to be essential for retinal integrity. In addition, we found multiple statistically significant gene-phenotype associations that have not been reported previously and decided to target one of these genes, Sfxn3 (encoding sideroflexin-3), using CRISPR/Cas9 technology. We demonstrate, using OCT, light microscopy, and electroretinography, that two Sfxn3 -/- mouse lines developed progressive and severe outer retinal degeneration. Electron microscopy showed thinning of the retinal pigment epithelium and disruption of the external limiting membrane. Using single-cell RNA sequencing of retinal cells isolated from C57BL/6J mice, we demonstrate that Sfxn3 is expressed in several bipolar cell subtypes, retinal ganglion cells, and some amacrine cell subtypes but not significantly in Müller cells or photoreceptors. In situ hybridization confirmed these findings. Furthermore, pathway analysis suggests that Sfxn3 may be associated with synaptic homeostasis. Importantly, electron microscopy analysis showed disruption of synapses and synaptic ribbons in the outer plexiform layer of Sfxn3 -/- mice. Our work describes a previously unknown requirement for Sfxn3 in retinal function.


Assuntos
Proteínas de Transporte de Cátions/genética , Degeneração Retiniana/genética , Segmento Externo das Células Fotorreceptoras da Retina/patologia , Animais , Modelos Animais de Doenças , Progressão da Doença , Eletrorretinografia , Etilnitrosoureia/toxicidade , Feminino , Humanos , Masculino , Camundongos , Microscopia Eletrônica , Mutagênese , Mutação/efeitos dos fármacos , Degeneração Retiniana/diagnóstico , Degeneração Retiniana/patologia , Segmento Externo das Células Fotorreceptoras da Retina/ultraestrutura , Epitélio Pigmentado da Retina/diagnóstico por imagem , Epitélio Pigmentado da Retina/patologia , Epitélio Pigmentado da Retina/ultraestrutura , Tomografia de Coerência Óptica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...