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1.
Brief Bioinform ; 25(1)2023 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-38221906

RESUMO

Large-scale imputation reference panels are currently available and have contributed to efficient genome-wide association studies through genotype imputation. However, whether large-size multi-ancestry or small-size population-specific reference panels are the optimal choices for under-represented populations continues to be debated. We imputed genotypes of East Asian (180k Japanese) subjects using the Trans-Omics for Precision Medicine reference panel and found that the standard imputation quality metric (Rsq) overestimated dosage r2 (squared correlation between imputed dosage and true genotype) particularly in marginal-quality bins. Variance component analysis of Rsq revealed that the increased imputed-genotype certainty (dosages closer to 0, 1 or 2) caused upward bias, indicating some systemic bias in the imputation. Through systematic simulations using different template switching rates (θ value) in the hidden Markov model, we revealed that the lower θ value increased the imputed-genotype certainty and Rsq; however, dosage r2 was insensitive to the θ value, thereby causing a deviation. In simulated reference panels with different sizes and ancestral diversities, the θ value estimates from Minimac decreased with the size of a single ancestry and increased with the ancestral diversity. Thus, Rsq could be deviated from dosage r2 for a subpopulation in the multi-ancestry panel, and the deviation represents different imputed-dosage distributions. Finally, despite the impact of the θ value, distant ancestries in the reference panel contributed only a few additional variants passing a predefined Rsq threshold. We conclude that the θ value substantially impacts the imputed dosage and the imputation quality metric value.


Assuntos
Estudo de Associação Genômica Ampla , Polimorfismo de Nucleotídeo Único , Humanos , Frequência do Gene , Genótipo
2.
Proc Natl Acad Sci U S A ; 118(23)2021 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-34088846

RESUMO

DNA synthesis by polymerases is essential for life. Deprotonation of the nucleophile 3'-OH is thought to be the obligatory first step in the DNA synthesis reaction. We have examined each entity surrounding the nucleophile 3'-OH in the reaction catalyzed by human DNA polymerase (Pol) η and delineated the deprotonation process by combining mutagenesis with steady-state kinetics, high-resolution structures of in crystallo reactions, and molecular dynamics simulations. The conserved S113 residue, which forms a hydrogen bond with the primer 3'-OH in the ground state, stabilizes the primer end in the active site. Mutation of S113 to alanine destabilizes primer binding and reduces the catalytic efficiency. Displacement of a water molecule that is hydrogen bonded to the 3'-OH using the 2'-OH of a ribonucleotide or 2'-F has little effect on catalysis. Moreover, combining the S113A mutation with 2'-F replacement, which removes two potential hydrogen acceptors of the 3'-OH, does not reduce the catalytic efficiency. We conclude that the proton can leave the O3' via alternative paths, supporting the hypothesis that binding of the third Mg2+ initiates the reaction by breaking the α-ß phosphodiester bond of an incoming deoxyribonucleoside triphosphate (dNTP).


Assuntos
DNA Polimerase Dirigida por DNA/química , DNA/química , Prótons , Substituição de Aminoácidos , DNA/genética , DNA Polimerase Dirigida por DNA/genética , Humanos , Cinética , Mutação de Sentido Incorreto
3.
Mol Genet Metab ; 140(3): 107668, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37549443

RESUMO

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency (VLCADD) is a relatively common inborn error of metabolism, but due to difficulty in accurately predicting affected status through newborn screening, molecular confirmation of the causative variants by sequencing of the ACADVL gene is necessary. Although the ACMG/AMP guidelines have helped standardize variant classification, ACADVL variant classification remains disparate due to a phenotype that can be nonspecific, the possibility of variants that produce late-onset disease, and relatively high carrier frequency, amongst other challenges. Therefore, an ACADVL-specific variant curation expert panel (VCEP) was created to facilitate the specification of the ACMG/AMP guidelines for VLCADD. We expect these guidelines to help streamline, increase concordance, and expedite the classification of ACADVL variants.


Assuntos
Erros Inatos do Metabolismo Lipídico , Doenças Mitocondriais , Doenças Musculares , Humanos , Recém-Nascido , Acil-CoA Desidrogenase de Cadeia Longa/genética , Síndrome Congênita de Insuficiência da Medula Óssea/genética , Testes Genéticos , Variação Genética , Erros Inatos do Metabolismo Lipídico/diagnóstico , Erros Inatos do Metabolismo Lipídico/genética , Doenças Mitocondriais/genética , Doenças Musculares/genética
4.
Proc Natl Acad Sci U S A ; 115(42): 10660-10665, 2018 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-30275308

RESUMO

Oxidatively induced DNA lesions 8,5'-cyclopurine-2'-deoxynucleosides (cdPus) are prevalent and cytotoxic by impeding DNA replication and transcription. Both the 5'R- and 5'S-diastereomers of cdPu can be removed by nucleotide excision repair; however, the 5'S-cdPu is more resistant to repair than the 5'R counterpart. Here, we report the crystal structures of human polymerase (Pol) η bypassing 5'S-8,5'-cyclo-2'-deoxyadenosine (cdA) in insertion and the following two extension steps. The cdA-containing DNA structures vary in response to the protein environment. Supported by the "molecular splint" of Pol η, the structure of 5'S-cdA at 1.75-Šresolution reveals that the backbone is pinched toward the minor groove and the adenine base is tilted. In the templating position, the cdA takes up the extra space usually reserved for the thymine dimer, and dTTP is efficiently incorporated by Pol η in the presence of Mn2+ Rigid distortions of the DNA duplex by cdA, however, prevent normal base pairing and hinder immediate primer extension by Pol η. Our results provide structural insights into the strong replication blockage effect and the mutagenic property of the cdPu lesions in cells.


Assuntos
Dano ao DNA , DNA Polimerase Dirigida por DNA/química , DNA Polimerase Dirigida por DNA/metabolismo , Desoxiadenosinas/toxicidade , Nucleotídeos/metabolismo , Pareamento de Bases , Cálcio/química , Cálcio/metabolismo , Cristalografia por Raios X , Reparo do DNA , Replicação do DNA , Humanos , Magnésio/química , Magnésio/metabolismo , Manganês/química , Manganês/metabolismo , Modelos Moleculares , Mutagênicos , Nucleotídeos/química , Conformação Proteica
5.
J Med Ethics ; 46(1): 43-47, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31462452

RESUMO

Many supporters of 'moral bioenhancement' (MBE), the use of biomedical interventions for moral improvement, have been criticised for having unrealistic proposals. The interventions they suggest have often been called infeasible and their implementation plans vague or unethical. I dispute these criticisms by showing that various interventions to implement MBE are practically and ethically feasible enough to warrant serious consideration. Such interventions include transcranial direct current stimulation over the medial and dorsolateral prefrontal cortex, as well as supplementation with lithium and omega-3. Considering their efficacy and feasibility, it is strange that these interventions have rarely been proposed or discussed as MBE. I review evidence that each of those interventions can reduce antisocial behaviour, reduce racial bias, increase executive function or increase prosocial traits like fairness and altruism. I then specify and defend realistic, ethically permissible ways to implement these interventions, especially for violent offenders and public servants-the former as rehabilitation and the latter to meet the high standards of their occupations. These interventions could be given to violent offenders in exchange for a reduced sentence or compulsorily in some cases. Potential intervention methods for non-prisoners include increasing the USDA-recommended dose of omega-3, encouraging food companies to supplement their products with omega-3 or trace lithium, requiring MBE for employment as a police officer or political leader, and insurance companies providing discounts for undergoing MBE. In some reasonably limited form, using these interventions may be a good first step to implement the project of MBE.


Assuntos
Melhoramento Biomédico/ética , Ácidos Graxos Ômega-3/administração & dosagem , Lítio/administração & dosagem , Princípios Morais , Valores Sociais , Estimulação Transcraniana por Corrente Contínua , Altruísmo , Transtorno da Personalidade Antissocial/prevenção & controle , Melhoramento Biomédico/métodos , Criminosos , Dissidências e Disputas , Função Executiva , Humanos , Polícia , Política , Córtex Pré-Frontal , Racismo/prevenção & controle , Justiça Social , Violência/prevenção & controle
6.
Proc Natl Acad Sci U S A ; 113(43): E6669-E6678, 2016 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-27791036

RESUMO

Activating mutations in FMS-like tyrosine kinase 3 (FLT3) are common in acute myeloid leukemia (AML) and drive leukemic cell growth and survival. Although FLT3 inhibitors have shown considerable promise for the treatment of AML, they ultimately fail to achieve long-term remissions as monotherapy. To identify genetic targets that can sensitize AML cells to killing by FLT3 inhibitors, we performed a genome-wide RNA interference (RNAi)-based screen that identified ATM (ataxia telangiectasia mutated) as being synthetic lethal with FLT3 inhibitor therapy. We found that inactivating ATM or its downstream effector glucose 6-phosphate dehydrogenase (G6PD) sensitizes AML cells to FLT3 inhibitor induced apoptosis. Examination of the cellular metabolome showed that FLT3 inhibition by itself causes profound alterations in central carbon metabolism, resulting in impaired production of the antioxidant factor glutathione, which was further impaired by ATM or G6PD inactivation. Moreover, FLT3 inhibition elicited severe mitochondrial oxidative stress that is causative in apoptosis and is exacerbated by ATM/G6PD inhibition. The use of an agent that intensifies mitochondrial oxidative stress in combination with a FLT3 inhibitor augmented elimination of AML cells in vitro and in vivo, revealing a therapeutic strategy for the improved treatment of FLT3 mutated AML.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Resistencia a Medicamentos Antineoplásicos/genética , Regulação Leucêmica da Expressão Gênica , Glucosefosfato Desidrogenase/genética , Leucemia Mieloide Aguda/genética , Tirosina Quinase 3 Semelhante a fms/genética , Animais , Antineoplásicos/farmacologia , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Benzotiazóis/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Quimioterapia Combinada , Feminino , Glucosefosfato Desidrogenase/antagonistas & inibidores , Glucosefosfato Desidrogenase/metabolismo , Humanos , Hidrazinas/farmacologia , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/patologia , Camundongos Endogâmicos NOD , Pessoa de Meia-Idade , Oxirredução , Compostos de Fenilureia/farmacologia , Inibidores de Proteínas Quinases/farmacologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Análise de Sobrevida , Ensaios Antitumorais Modelo de Xenoenxerto , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Tirosina Quinase 3 Semelhante a fms/metabolismo
7.
Nucleic Acids Res ; 44(3): e22, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26384417

RESUMO

Next-generation sequencing (NGS) technologies have transformed genomic research and have the potential to revolutionize clinical medicine. However, the background error rates of sequencing instruments and limitations in targeted read coverage have precluded the detection of rare DNA sequence variants by NGS. Here we describe a method, termed CypherSeq, which combines double-stranded barcoding error correction and rolling circle amplification (RCA)-based target enrichment to vastly improve NGS-based rare variant detection. The CypherSeq methodology involves the ligation of sample DNA into circular vectors, which contain double-stranded barcodes for computational error correction and adapters for library preparation and sequencing. CypherSeq is capable of detecting rare mutations genome-wide as well as those within specific target genes via RCA-based enrichment. We demonstrate that CypherSeq is capable of correcting errors incurred during library preparation and sequencing to reproducibly detect mutations down to a frequency of 2.4 × 10(-7) per base pair, and report the frequency and spectra of spontaneous and ethyl methanesulfonate-induced mutations across the Saccharomyces cerevisiae genome.


Assuntos
DNA/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Mutação , Linhagem Celular , Genes p53 , Humanos , Reação em Cadeia da Polimerase/métodos , Saccharomyces cerevisiae/genética
8.
Proc Natl Acad Sci U S A ; 111(8): 2954-9, 2014 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-24449906

RESUMO

DNA polymerase ζ (Pol ζ) is a eukaryotic B-family DNA polymerase that specializes in translesion synthesis and is essential for normal embryogenesis. At a minimum, Pol ζ consists of a catalytic subunit Rev3 and an accessory subunit Rev7. Mammalian Rev3 contains >3,000 residues and is twice as large as the yeast homolog. To date, no vertebrate Pol ζ has been purified for biochemical characterization. Here we report purification of a series of human Rev3 deletion constructs expressed in HEK293 cells and identification of a minimally catalytically active human Pol ζ variant. With a tagged form of an active Pol ζ variant, we isolated two additional accessory subunits of human Pol ζ, PolD2 and PolD3. The purified four-subunit Pol ζ4 (Rev3-Rev7-PolD2-PolD3) is much more efficient and more processive at bypassing a 1,2-intrastrand d(GpG)-cisplatin cross-link than the two-subunit Pol ζ2 (Rev3-Rev7). We show that complete bypass of cisplatin lesions requires Pol η to insert dCTP opposite the 3' guanine and Pol ζ4 to extend the primers.


Assuntos
Cisplatino/metabolismo , Reparo do DNA/fisiologia , DNA Polimerase Dirigida por DNA/metabolismo , DNA/biossíntese , Cromatografia em Gel , Cromatografia por Troca Iônica , DNA Polimerase III/metabolismo , Primers do DNA/genética , Proteínas de Ligação a DNA/metabolismo , DNA Polimerase Dirigida por DNA/isolamento & purificação , Fluoresceína , Células HEK293 , Holoenzimas/isolamento & purificação , Holoenzimas/metabolismo , Humanos , Proteínas Mad2/metabolismo
9.
Proc Natl Acad Sci U S A ; 111(25): 9133-8, 2014 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-24927576

RESUMO

Platinum drugs are a mainstay of anticancer chemotherapy. Nevertheless, tumors often display inherent or acquired resistance to platinum-based treatments, prompting the search for new compounds that do not exhibit cross-resistance with current therapies. Phenanthriplatin, cis-diamminephenanthridinechloroplatinum(II), is a potent monofunctional platinum complex that displays a spectrum of activity distinct from those of the clinically approved platinum drugs. Inhibition of RNA polymerases by phenanthriplatin lesions has been implicated in its mechanism of action. The present study evaluates the ability of phenanthriplatin lesions to inhibit DNA replication, a function disrupted by traditional platinum drugs. Phenanthriplatin lesions effectively inhibit DNA polymerases ν, ζ, and κ and the Klenow fragment. In contrast to results obtained with DNA damaged by cisplatin, all of these polymerases were capable of inserting a base opposite a phenanthriplatin lesion, but only Pol η, an enzyme efficient in translesion synthesis, was able to fully bypass the adduct, albeit with low efficiency. X-ray structural characterization of Pol η complexed with site-specifically platinated DNA at both the insertion and +1 extension steps reveals that phenanthriplatin on DNA interacts with and inhibits Pol η in a manner distinct from that of cisplatin-DNA adducts. Unlike cisplatin and oxaliplatin, the efficacies of which are influenced by Pol η expression, phenanthriplatin is highly toxic to both Pol η+ and Pol η- cells. Given that increased expression of Pol η is a known mechanism by which cells resist cisplatin treatment, phenanthriplatin may be valuable in the treatment of cancers that are, or can easily become, resistant to cisplatin.


Assuntos
Antineoplásicos , Dano ao DNA , DNA de Neoplasias , DNA Polimerase Dirigida por DNA , Proteínas de Neoplasias , Neoplasias , Compostos Organoplatínicos , Fenantridinas , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Cristalografia por Raios X , DNA de Neoplasias/biossíntese , DNA de Neoplasias/química , DNA Polimerase Dirigida por DNA/química , DNA Polimerase Dirigida por DNA/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Humanos , Proteínas de Neoplasias/química , Proteínas de Neoplasias/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Compostos Organoplatínicos/química , Compostos Organoplatínicos/farmacologia , Fenantridinas/química , Fenantridinas/farmacologia , Relação Estrutura-Atividade
10.
Nature ; 465(7301): 1044-8, 2010 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-20577208

RESUMO

The variant form of the human syndrome xeroderma pigmentosum (XPV) is caused by a deficiency in DNA polymerase eta (Poleta), a DNA polymerase that enables replication through ultraviolet-induced pyrimidine dimers. Here we report high-resolution crystal structures of human Poleta at four consecutive steps during DNA synthesis through cis-syn cyclobutane thymine dimers. Poleta acts like a 'molecular splint' to stabilize damaged DNA in a normal B-form conformation. An enlarged active site accommodates the thymine dimer with excellent stereochemistry for two-metal ion catalysis. Two residues conserved among Poleta orthologues form specific hydrogen bonds with the lesion and the incoming nucleotide to assist translesion synthesis. On the basis of the structures, eight Poleta missense mutations causing XPV can be rationalized as undermining the molecular splint or perturbing the active-site alignment. The structures also provide an insight into the role of Poleta in replicating through D loop and DNA fragile sites.


Assuntos
DNA Polimerase Dirigida por DNA/química , DNA Polimerase Dirigida por DNA/metabolismo , Trifosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/metabolismo , Sequência de Bases , Biocatálise , Domínio Catalítico , Cristalografia por Raios X , DNA/química , DNA/metabolismo , Dano ao DNA , DNA Polimerase Dirigida por DNA/genética , Humanos , Cinética , Modelos Moleculares , Mutação de Sentido Incorreto/genética , Dímeros de Pirimidina/genética , Dímeros de Pirimidina/metabolismo , Relação Estrutura-Atividade , Xeroderma Pigmentoso/enzimologia , Xeroderma Pigmentoso/genética
11.
Proc Natl Acad Sci U S A ; 110(3): 978-83, 2013 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-23277542

RESUMO

The oncogenic transcription factor c-Myc causes transformation and tumorigenesis, but it can also induce apoptotic cell death. Although tumor suppressors are necessary for c-Myc to induce apoptosis, the pathways and mechanisms are unclear. To further understand how c-Myc switches from an oncogenic protein to an apoptotic protein, we examined the mechanism of p53-independent c-Myc-induced apoptosis. We show that the tumor suppressor protein ARF mediates this switch by inhibiting ubiquitylation of the c-Myc transcriptional domain (TD). Whereas TD ubiquitylation is critical for c-Myc canonical transcriptional activity and transformation, inhibition of ubiquitylation leads to the induction of the noncanonical c-Myc target gene, Egr1, which is essential for efficient c-Myc-induced p53-independent apoptosis. ARF inhibits the interaction of c-Myc with the E3 ubiquitin ligase Skp2. Overexpression of Skp2, which occurs in many human tumors, inhibits the recruitment of ARF to the Egr1 promoter, leading to inhibition of c-Myc-induced apoptosis. Therapeutic strategies could be developed to activate this intrinsic apoptotic activity of c-Myc to inhibit tumorigenesis.


Assuntos
Apoptose/fisiologia , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Substituição de Aminoácidos , Animais , Apoptose/genética , Ligação Competitiva , Transformação Celular Neoplásica , Células Cultivadas , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Proteína 1 de Resposta de Crescimento Precoce/genética , Técnicas de Inativação de Genes , Genes myc , Células HeLa , Humanos , Camundongos , Mutagênese Sítio-Dirigida , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Quinases Associadas a Fase S/metabolismo , Transcrição Gênica , Ubiquitinação
12.
Proc Natl Acad Sci U S A ; 110(20): 8146-51, 2013 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-23630267

RESUMO

Somatic hypermutation is programmed base substitutions in the variable regions of Ig genes for high-affinity antibody generation. Two motifs, RGYW and WA (R, purine; Y, pyrimidine; W, A or T), have been found to be somatic hypermutation hotspots. Overwhelming evidence suggests that DNA polymerase η (Pol η) is responsible for converting the WA motif to WG by misincorporating dGTP opposite the templating T. To elucidate the molecular mechanism, crystal structures and kinetics of human Pol η substituting dGTP for dATP in four sequence contexts, TA, AA, GA, and CA, have been determined and compared. The T:dGTP wobble base pair is stabilized by Gln-38 and Arg-61, two uniquely conserved residues among Pol η. Weak base paring of the W (T:A or A:T) at the primer end and their distinct interactions with Pol η lead to misincorporation of G in the WA motif. Between two WA motifs, our kinetic and structural data indicate that A-to-G mutation occurs more readily in the TA context than AA. Finally, Pol η can extend the T:G mispair efficiently to complete the mutagenesis.


Assuntos
DNA Polimerase Dirigida por DNA/química , Hipermutação Somática de Imunoglobulina , Trifosfato de Adenosina/química , Motivos de Aminoácidos , Cátions , Nucleotídeos de Desoxiguanina/química , Humanos , Imunoglobulinas/química , Cinética , Mutagênese Sítio-Dirigida , Mutação , Conformação de Ácido Nucleico
13.
Proc Natl Acad Sci U S A ; 109(19): 7269-74, 2012 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-22529383

RESUMO

Cisplatin (cis-diamminedichloroplatinum) and related compounds cause DNA damage and are widely used as anticancer agents. Chemoresistance to cisplatin treatment is due in part to translesion synthesis by human DNA polymerase η (hPol η). Here, we report crystal structures of hPol η complexed with intrastrand cisplatin-1,2-cross-linked DNA, representing four consecutive steps in translesion synthesis. In contrast to the generally enlarged and nondiscriminating active site of Y-family polymerases like Dpo4, Pol η is specialized for efficient bypass of UV-cross-linked pyrimidine dimers. Human Pol η differs from the yeast homolog in its binding of DNA template. To incorporate deoxycytidine opposite cisplatin-cross-linked guanines, hPol η undergoes a specific backbone rearrangement to accommodate the larger base dimer and minimizes the DNA distortion around the lesion. Our structural analyses show why Pol η is inefficient at extending primers after cisplatin lesions, which necessitates a second translesion DNA polymerase to complete bypass in vivo. A hydrophobic pocket near the primer-binding site in human Pol η is identified as a potential drug target for inhibiting translesion synthesis and, thereby, reducing chemoresistance.


Assuntos
Cisplatino/química , DNA Polimerase Dirigida por DNA/química , DNA/química , Resistência a Medicamentos , Trifosfato de Adenosina/química , Trifosfato de Adenosina/metabolismo , Sequência de Bases , Sítios de Ligação/genética , Cisplatino/farmacologia , Reagentes de Ligações Cruzadas/química , Reagentes de Ligações Cruzadas/farmacologia , Cristalografia por Raios X , DNA/genética , DNA/metabolismo , DNA Polimerase Dirigida por DNA/genética , DNA Polimerase Dirigida por DNA/metabolismo , Humanos , Cinética , Modelos Moleculares , Estrutura Molecular , Mutação , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Neoplasias/genética , Conformação de Ácido Nucleico , Conformação Proteica , Estrutura Terciária de Proteína , Dímeros de Pirimidina/química , Dímeros de Pirimidina/metabolismo , Homologia de Sequência de Aminoácidos
14.
Sensors (Basel) ; 15(3): 5474-503, 2015 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-25751081

RESUMO

The Wireless Sensor Network similarity search problem has received considerable research attention due to sensor hardware imprecision and environmental parameter variations. Most of the state-of-the-art distributed data centric storage (DCS) schemes lack optimization for similarity queries of events. In this paper, a DCS scheme with metric based similarity searching (DCSMSS) is proposed. DCSMSS takes motivation from vector distance index, called iDistance, in order to transform the issue of similarity searching into the problem of an interval search in one dimension. In addition, a sector based distance routing algorithm is used to efficiently route messages. Extensive simulation results reveal that DCSMSS is highly efficient and significantly outperforms previous approaches in processing similarity search queries.

15.
Am J Hematol ; 89(9): 896-903, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24891015

RESUMO

Treatment of BCR-ABL1(+) leukemia has been revolutionized with the development of tyrosine kinase inhibitors. However, patients with BCR-ABL1(+) acute lymphoblastic leukemia and subsets of patients with chronic myeloid leukemia are at high risk of relapse despite kinase inhibition therapy, necessitating novel treatment strategies. We previously reported synthetic lethality in BCR-ABL1(+) leukemia cells by blocking both calcineurin/NFAT signaling and BCR-ABL1, independent of drug efflux inhibition by cyclosporine. Here, using RNA-interference we confirm that calcineurin inhibition sensitizes BCR-ABL1(+) cells to tyrosine kinase inhibition in vitro. However, when we performed pharmacokinetic and pharmacodynamic studies of dasatinib and cyclosporine in mice, we found that co-administration of cyclosporine increases peak concentrations and the area under the curve of dasatinib, which contributes to the enhanced disease control. We also report the clinical experience of two subjects in whom we observed more hematopoietic toxicity than expected while enrolled in a Phase Ib trial designed to assess the safety and tolerability of adding cyclosporine to dasatinib in humans. Thus, the anti-leukemia benefit of co-administration of cyclosporine and dasatinib is mechanistically pleiotropic, but may not be tolerable, at least as administered in this trial. These data highlight some of the challenges associated with combining targeted agents to treat leukemia.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Inibidores de Calcineurina , Proteínas de Fusão bcr-abl/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Adulto , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Linhagem Celular Tumoral , Ciclosporina/efeitos adversos , Ciclosporina/farmacocinética , Ciclosporina/uso terapêutico , Dasatinibe , Sinergismo Farmacológico , Feminino , Citometria de Fluxo , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/enzimologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Inibidores de Proteínas Quinases/efeitos adversos , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinas/efeitos adversos , Pirimidinas/farmacocinética , Pirimidinas/uso terapêutico , Tiazóis/efeitos adversos , Tiazóis/farmacocinética , Tiazóis/uso terapêutico , Resultado do Tratamento
16.
Crit Care ; 17(2): R60, 2013 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-23531337

RESUMO

INTRODUCTION: Although many sepsis biomarkers have shown promise in selected patient groups, only C-reactive protein and procalcitonin (PCT) have entered clinical practice. The aim of this study was to evaluate three promising novel sepsis biomarkers in unselected patients at admission to intensive care. We assessed the performance of pancreatic stone protein (PSP), soluble CD25 (sCD25) and heparin binding protein (HBP) in distinguishing patients with sepsis from those with a non-infective systemic inflammatory response and the ability of these markers to indicate severity of illness. METHODS: Plasma levels of the biomarkers, PCT and selected inflammatory cytokines were measured in samples taken from 219 patients during the first six hours of admission to intensive or high dependency care. Patients with a systemic inflammatory response were categorized as having sepsis or a non-infective aetiology, with or without markers of severity, using standard diagnostic criteria. RESULTS: Both PSP and sCD25 performed well as biomarkers of sepsis irrespective of severity of illness. For both markers the area under the receiver operating curve (AUC) was greater than 0.9; PSP 0.927 (0.887 to 0.968) and sCD25 0.902 (0.854 to 0.949). Procalcitonin and IL6 also performed well as markers of sepsis whilst in this intensive care unit (ICU) population, HBP did not: PCT 0.840 (0.778 to 0.901), IL6 0.805 (0.739 to 0.870) and HBP 0.607 (0.519 to 0.694). Levels of both PSP and PCT reflected severity of illness and both markers performed well in differentiating patients with severe sepsis from severely ill patients with a non-infective systemic inflammatory response: AUCs 0.955 (0.909 to 1) and 0.837 (0.732 to 0.941) respectively. Although levels of sCD25 did not correlate with severity, the addition of sCD25 to either PCT or PSP in a multivariate model improved the diagnostic accuracy of either marker alone. CONCLUSIONS: PSP and sCD25 perform well as sepsis biomarkers in patients with suspected sepsis at the time of admission to intensive or high dependency care. These markers warrant further assessment of their prognostic value. Whereas previously published data indicate HBP has clinical utility in the emergency department, it did not perform well in an intensive-care population.


Assuntos
Unidades de Terapia Intensiva , Subunidade alfa de Receptor de Interleucina-2/sangue , Litostatina/sangue , Admissão do Paciente , Sepse/sangue , Sepse/diagnóstico , Adulto , Idoso , Biomarcadores/sangue , Feminino , Humanos , Unidades de Terapia Intensiva/tendências , Masculino , Pessoa de Meia-Idade , Admissão do Paciente/tendências , Estudos Prospectivos
17.
J Med Internet Res ; 15(7): e138, 2013 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-23853350

RESUMO

BACKGROUND: Point-of-care international normalized ratio (INR) monitoring devices simplify warfarin management by allowing selected patients to monitor their own therapy in their homes. Patient self-testing (PST) has been shown to improve the clinical outcomes of warfarin therapy compared to usual care. OBJECTIVE: To compare management of warfarin therapy using PST combined with online supervision by physicians via a custom system with usual warfarin management, which involved laboratory testing and physician dosing. METHODS: Interested patients were recruited via community pharmacies to participate in a warfarin PST training program. Participants were required to have a long-term indication for warfarin, have been taking warfarin for at least 6 months, and have Internet access in their home. The training involved two sessions covering theoretical aspects of warfarin therapy, use of the CoaguChek XS, and the study website. Following training, patients monitored their INR once weekly for up to 3 months. Patients and physicians utilized a secure website to communicate INR values, dosage recommendations, and clinical incidents. Physicians provided a 6-12 month history of INR results for comparison with study results. The percentage of time spent within the therapeutic INR range (TTR) was the primary outcome, with participants acting as their own historical controls. The percentage of INR tests in range and participant satisfaction were secondary outcomes. RESULTS: Sixteen patients completed training requirements. The mean age of participants was 69.8 (SD 10.1) years. TTR improved significantly from 66.4% to 78.4% during PST (P=.01), and the number of tests within the target range also improved significantly (from 66.0% at prior to the study to 75.9% during PST; P=.04). Patients and physicians expressed a high degree of satisfaction with the monitoring strategy and online system. CONCLUSIONS: PST supported by an online system for supervision was associated with improved INR control compared to usual care in a small group of elderly patients. Further research is warranted to investigate the clinical outcomes and cost-effectiveness of online systems to support patients monitoring medications and chronic conditions in the home.


Assuntos
Anticoagulantes/uso terapêutico , Coeficiente Internacional Normatizado , Educação de Pacientes como Assunto/métodos , Participação do Paciente , Varfarina/uso terapêutico , Idoso , Feminino , Humanos , Internet , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Tasmânia
18.
Clin Cancer Res ; 29(18): 3813-3825, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37389981

RESUMO

PURPOSE: Cancer drug development is currently limited by a paradigm of preclinical evaluation that does not adequately recapitulate the complexity of the intact human tumor microenvironment (TME). To overcome this, we combined trackable intratumor microdosing (CIVO) with spatial biology readouts to directly assess drug effects in patient tumors in situ. EXPERIMENTAL DESIGN: In a first-of-its-kind phase 0 clinical trial, we explored the effects of an investigational stage SUMOylation-activating enzyme (SAE) inhibitor, subasumstat (TAK-981) in 12 patients with head and neck carcinoma (HNC). Patients scheduled for tumor resection received percutaneous intratumor injections of subasumstat and vehicle control 1 to 4 days before surgery, resulting in spatially localized and graded regions of drug exposure (∼1,000-2,000 µm in diameter). Drug-exposed (n = 214) and unexposed regions (n = 140) were compared by GeoMx Digital Spatial Profiler, with evaluation at single-cell resolution in a subset of these by CosMx Spatial Molecular Imager. RESULTS: Localized regions of subasumstat exposure revealed SUMO pathway inhibition, elevation of type I IFN response, and inhibition of cell cycle across all tumor samples. Single-cell analysis by CosMx demonstrated cell-cycle inhibition specific to the tumor epithelium, and IFN pathway induction commensurate with a TME shift from immune-suppressive to immune-permissive. CONCLUSIONS: Pairing CIVO with spatial profiling enabled detailed investigation of response to subasumstat across a diverse sampling of native and intact TME. We demonstrate that drug mechanism of action can be directly evaluated in a spatially precise manner in the most translationally relevant setting: an in situ human tumor.


Assuntos
Antineoplásicos , Neoplasias de Cabeça e Pescoço , Humanos , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Inibidores Enzimáticos , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Microambiente Tumoral
19.
bioRxiv ; 2023 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-37425692

RESUMO

In combination with cell intrinsic properties, interactions in the tumor microenvironment modulate therapeutic response. We leveraged high-plex single-cell spatial transcriptomics to dissect the remodeling of multicellular neighborhoods and cell-cell interactions in human pancreatic cancer associated with specific malignant subtypes and neoadjuvant chemotherapy/radiotherapy. We developed Spatially Constrained Optimal Transport Interaction Analysis (SCOTIA), an optimal transport model with a cost function that includes both spatial distance and ligand-receptor gene expression. Our results uncovered a marked change in ligand-receptor interactions between cancer-associated fibroblasts and malignant cells in response to treatment, which was supported by orthogonal datasets, including an ex vivo tumoroid co-culture system. Overall, this study demonstrates that characterization of the tumor microenvironment using high-plex single-cell spatial transcriptomics allows for identification of molecular interactions that may play a role in the emergence of chemoresistance and establishes a translational spatial biology paradigm that can be broadly applied to other malignancies, diseases, and treatments.

20.
bioRxiv ; 2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-38014063

RESUMO

Background: Immunotherapy (IO) has improved survival for patients with advanced clear cell renal cell carcinoma (ccRCC), but resistance to therapy develops in most patients. We use cellular-resolution spatial transcriptomics in patients with IO naïve and IO exposed primary ccRCC tumors to better understand IO resistance. Spatial molecular imaging (SMI) was obtained for tumor and adjacent stroma samples. Spatial gene set enrichment analysis (GSEA) and autocorrelation (coupling with high expression) of ligand-receptor transcript pairs were assessed. Multiplex immunofluorescence (mIF) validation was used for significant autocorrelative findings and the cancer genome atlas (TCGA) and the clinical proteomic tumor analysis consortium (CPTAC) databases were queried to assess bulk RNA expression and proteomic correlates. Results: 21 patient samples underwent SMI. Viable tumors following IO harbored more stromal CD8+ T cells and neutrophils than IO naïve tumors. YES1 was significantly upregulated in IO exposed tumor cells. The epithelial-mesenchymal transition pathway was enriched on spatial GSEA and the associated transcript pair COL4A1-ITGAV had significantly higher autocorrelation in the stroma. Fibroblasts, tumor cells, and endothelium had the relative highest expression. More integrin αV+ cells were seen in IO exposed stroma on mIF validation. Compared to other cancers in TCGA, ccRCC tumors have the highest expression of both COL4A1 and ITGAV. In CPTAC, collagen IV protein was more abundant in advanced stages of disease. Conclusions: On spatial transcriptomics, COL4A1 and ITGAV were more autocorrelated in IO-exposed stroma compared to IO-naïve tumors, with high expression amongst fibroblasts, tumor cells, and endothelium. Integrin represents a potential therapeutic target in IO treated ccRCC.

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