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1.
Proc Natl Acad Sci U S A ; 115(6): 1322-1327, 2018 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-29358382

RESUMO

Prevention and early intervention are the most effective ways of avoiding or minimizing psychological, physical, and financial suffering from cancer. However, such proactive action requires the ability to predict the individual's susceptibility to cancer with a measure of probability. Of the triad of cancer-causing factors (inherited genomic susceptibility, environmental factors, and lifestyle factors), the inherited genomic component may be derivable from the recent public availability of a large body of whole-genome variation data. However, genome-wide association studies have so far showed limited success in predicting the inherited susceptibility to common cancers. We present here a multiple classification approach for predicting individuals' inherited genomic susceptibility to acquire the most likely phenotype among a panel of 20 major common cancer types plus 1 "healthy" type by application of a supervised machine-learning method under competing conditions among the cohorts of the 21 types. This approach suggests that, depending on the phenotypes of 5,919 individuals of "white" ethnic population in this study, (i) the portion of the cohort of a cancer type who acquired the observed type due to mostly inherited genomic susceptibility factors ranges from about 33 to 88% (or its corollary: the portion due to mostly environmental and lifestyle factors ranges from 12 to 67%), and (ii) on an individual level, the method also predicts individuals' inherited genomic susceptibility to acquire the other types ranked with associated probabilities. These probabilities may provide practical information for individuals, heath professionals, and health policymakers related to prevention and/or early intervention of cancer.


Assuntos
Predisposição Genética para Doença , Aprendizado de Máquina , Neoplasias/genética , Polimorfismo de Nucleotídeo Único , Genoma Humano , Humanos , Estilo de Vida , Probabilidade
2.
Proc Natl Acad Sci U S A ; 112(5): 1559-64, 2015 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-25591581

RESUMO

A successful pregnancy depends on a complex process that establishes fetomaternal tolerance. Seminal plasma is known to induce maternal immune tolerance to paternal alloantigens, but the seminal factors that regulate maternal immunity have yet to be characterized. Here, we show that a soluble form of CD38 (sCD38) released from seminal vesicles to the seminal plasma plays a crucial role in inducing tolerogenic dendritic cells and CD4(+) forkhead box P3(+) (Foxp3(+)) regulatory T cells (Tregs), thereby enhancing maternal immune tolerance and protecting the semiallogeneic fetus from resorption. The abortion rate in BALB/c females mated with C57BL/6 Cd38(-/-) males was high compared with that in females mated with Cd38(+/+) males, and this was associated with a reduced proportion of Tregs within the CD4(+) T-cell pool. Direct intravaginal injection of sCD38 to CBA/J pregnant mice at preimplantation increased Tregs and pregnancy rates in mice under abortive sonic stress from 48 h after mating until euthanasia. Thus, sCD38 released from seminal vesicles to the seminal plasma acts as an immunoregulatory factor to protect semiallogeneic fetuses from maternal immune responses.


Assuntos
ADP-Ribosil Ciclase 1/imunologia , Tolerância Imunológica , Troca Materno-Fetal , Sêmen/imunologia , ADP-Ribosil Ciclase 1/genética , Animais , Células Dendríticas/imunologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Gravidez
3.
Reproduction ; 154(5): 595-605, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28780571

RESUMO

CD31 has been shown to play a role in endothelial cell migration and angiogenesis, which are critical to the formation and function of the endometrium and myometrium in uterine development during early pregnancy. However, the role of CD31 in uterine receptivity during blastocyst implantation is poorly understood. The pregnancy rate in CD31-/- female mice mated with CD31+/+ male mice was higher than that observed in CD31+/+ female mice mated with CD31+/+ male mice. During the receptive phase of implantation, uterine glands were more developed in CD31-/- mice than in CD31+/+ mice, and the uterine weights of CD31-/- mice were increased. Leukemia inhibitory factor (LIF) was highly expressed in the CD31-/- mice during implantation and the expression of LIF was up-regulated by estradiol-17ß (E2 ) + progesterone (P4 ) in ovariectomized CD31-/- mice, compared with CD31+/+ mice at 8 h after hormone treatment. E2 -induced protein synthesis was inhibited by P4 in the CD31+/+ uterus, but not in the uterus of CD31-/- mice. Also, STAT3, HAND2, LIF, and mTOR signals were enhanced in CD31-/- mice. Stromal DNA replication was highly activated in the uterus of CD31-/- mice, manifested by upregulated cyclin series signaling and PCNA expression after E2 + P4 treatment. Collectively, CD31 inhibits E2 -mediated epithelial proliferation via recruitment and phosphorylation of SHP-2 upon receiving P4 signal in early pregnancy.


Assuntos
Molécula-1 de Adesão Celular Endotelial a Plaquetas/fisiologia , Progesterona/farmacologia , Útero/metabolismo , Animais , Implantação do Embrião/efeitos dos fármacos , Implantação do Embrião/genética , Endométrio/efeitos dos fármacos , Endométrio/metabolismo , Estradiol/farmacologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Molécula-1 de Adesão Celular Endotelial a Plaquetas/genética , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Gravidez , Transdução de Sinais/efeitos dos fármacos , Útero/efeitos dos fármacos
4.
Proc Natl Acad Sci U S A ; 110(5): 1708-13, 2013 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-23302691

RESUMO

Epigenetic silencing in mammals involves DNA methylation and posttranslational modifications of core histones. Here we show that the H1 linker histone plays a key role in regulating both DNA methylation and histone H3 methylation at the H19 and Gtl2 loci in mouse ES cells. Some, but not all, murine H1 subtypes interact with DNA methyltransferases DNMT1 and DNMT3B. The interactions are direct and require a portion of the H1 C-terminal domain. Expression of an H1 subtype that interacts with DNMT1 and DNMT3B in ES cells leads to their recruitment and DNA methylation of the H19 and Gtl2 imprinting control regions. H1 also interferes with binding of the SET7/9 histone methyltransferase to the imprinting control regions, inhibiting production of an activating methylation mark on histone H3 lysine 4. H1-dependent recruitment of DNMT1 and DNMT3B and interference with the binding of SET7/9 also were observed with chromatin reconstituted in vitro. The data support a model in which H1 plays an active role in helping direct two processes that lead to the formation of epigenetic silencing marks. The data also provide evidence for functional differences among the H1 subtypes expressed in somatic mammalian cells.


Assuntos
Metilação de DNA , Células-Tronco Embrionárias/metabolismo , Epigênese Genética , Histonas/metabolismo , Animais , Western Blotting , Células Cultivadas , Cromatina/genética , Cromatina/metabolismo , DNA (Citosina-5-)-Metiltransferase 1 , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismo , Expressão Gênica , Impressão Genômica/genética , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/genética , Metilação , Camundongos , Camundongos Knockout , Ligação Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Longo não Codificante/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , DNA Metiltransferase 3B
5.
J Biol Chem ; 289(23): 16362-73, 2014 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-24759100

RESUMO

NAD glycohydrolases (NADases) catalyze the hydrolysis of NAD to ADP-ribose and nicotinamide. Although many members of the NADase family, including ADP-ribosyltransferases, have been cloned and characterized, the structure and function of NADases with pure hydrolytic activity remain to be elucidated. Here, we report the structural and functional characterization of a novel NADase from rabbit reticulocytes. The novel NADase is a glycosylated, glycosylphosphatidylinositol-anchored cell surface protein exclusively expressed in reticulocytes. shRNA-mediated knockdown of the NADase in bone marrow cells resulted in a reduction of erythroid colony formation and an increase in NAD level. Furthermore, treatment of bone marrow cells with NAD, nicotinamide, or nicotinamide riboside, which induce an increase in NAD content, resulted in a significant decrease in erythroid progenitors. These results indicate that the novel NADase may play a critical role in regulating erythropoiesis of hematopoietic stem cells by modulating intracellular NAD.


Assuntos
Eritropoese , Células-Tronco Hematopoéticas/metabolismo , NAD+ Nucleosidase/metabolismo , NAD/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Western Blotting , DNA Complementar , Glicosilação , Células HEK293 , Humanos , Microscopia Confocal , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , NAD+ Nucleosidase/química , NAD+ Nucleosidase/genética , Coelhos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Relação Estrutura-Atividade
6.
Cell Mol Life Sci ; 71(13): 2561-76, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24270855

RESUMO

The gamma (γ)-secretase holoenzyme is composed of four core proteins and cleaves APP to generate amyloid beta (Aß), a key molecule that causes major neurotoxicity during the early stage of Alzheimer's disease (AD). However, despite its important role in Aß production, little is known about the regulation of γ-secretase. OCIAD2, a novel modulator of γ-secretase that stimulates Aß production, and which was isolated from a genome-wide functional screen using cell-based assays and a cDNA library comprising 6,178 genes. Ectopic expression of OCIAD2 enhanced Aß production, while reduction of OCIAD2 expression suppressed it. OCIAD2 expression facilitated the formation of an active γ-secretase complex and enhanced subcellular localization of the enzyme components to lipid rafts. OCIAD2 interacted with nicastrin to stimulate γ-secretase activity. OCIAD2 also increased the interaction of nicastrin with C99 and stimulated APP processing via γ-secretase activation, but did not affect Notch processing. In addition, a cell-permeable Tat-OCIAD2 peptide that interfered with the interaction of OCIAD2 with nicastrin interrupted the γ-secretase-mediated AICD production. Finally, OCIAD2 expression was significantly elevated in the brain of AD patients and PDAPP mice. This study identifies OCIAD2 as a selective activator of γ-secretase to increase Aß generation.


Assuntos
Doença de Alzheimer/genética , Secretases da Proteína Precursora do Amiloide/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas de Neoplasias/metabolismo , Doença de Alzheimer/etiologia , Doença de Alzheimer/metabolismo , Secretases da Proteína Precursora do Amiloide/química , Secretases da Proteína Precursora do Amiloide/genética , Peptídeos beta-Amiloides/biossíntese , Animais , Fibroblastos/metabolismo , Biblioteca Gênica , Humanos , Glicoproteínas de Membrana/genética , Microdomínios da Membrana/metabolismo , Camundongos , Camundongos Knockout/metabolismo , Proteínas de Neoplasias/genética , Receptores Notch/metabolismo
7.
J Biol Chem ; 288(49): 35548-58, 2013 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-24165120

RESUMO

Nicotinic acid adenine dinucleotide phosphate (NAADP) is a second messenger for mobilizing Ca(2+) from intracellular stores in various cell types. Extracellular application of NAADP has been shown to elicit intracellular Ca(2+) signals, indicating that it is readily transported into cells. However, little is known about the functional role of this NAADP uptake system. Here, we show that NAADP is effectively transported into selected cell types involved in glucose homeostasis, such as adipocytes and pancreatic ß-cells, but not the acinar cells, in a high glucose-dependent manner. NAADP uptake was inhibitable by Ned-19, a NAADP mimic; dipyridamole, a nucleoside inhibitor; or NaN3, a metabolic inhibitor or under Ca(2+)-free conditions. Furthermore, NAADP was found to be released from pancreatic islets upon stimulation by high glucose. Consistently, administration of NAADP to type 2 diabetic mice improved glucose tolerance. We propose that NAADP is functioning as an autocrine/paracrine hormone important in glucose homeostasis. NAADP is thus a potential antidiabetic agent with therapeutic relevance.


Assuntos
Adipócitos/metabolismo , Glucose/metabolismo , Células Secretoras de Insulina/metabolismo , NADP/análogos & derivados , Animais , Comunicação Autócrina , Transporte Biológico Ativo , Sinalização do Cálcio , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Homeostase , Insulina/metabolismo , Cinética , Masculino , Camundongos , NADP/metabolismo , NADP/farmacologia , Comunicação Parácrina , Sistemas do Segundo Mensageiro
8.
Sci Rep ; 13(1): 6316, 2023 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-37072456

RESUMO

All current categorizations of human population, such as ethnicity, ancestry and race, are based on various selections and combinations of complex and dynamic common characteristics, that are mostly societal and cultural in nature, perceived by the members within or from outside of the categorized group. During the last decade, a massive amount of a new type of characteristics, that are exclusively genomic in nature, became available that allows us to analyze the inherited whole-genome demographics of extant human, especially in the fields such as human genetics, health sciences and medical practices (e.g., 1,2,3), where such health-related characteristics can be related to whole-genome-based categorization. Here we show the feasibility of deriving such whole-genome-based categorization. We observe that, within the available genomic data at present, (a) the study populations form about 14 genomic groups, each consisting of multiple ethnic groups; and (b), at an individual level, approximately 99.8%, on average, of the whole autosomal-genome contents are identical between any two individuals regardless of their genomic or ethnic groups.


Assuntos
Etnicidade , Genômica , Humanos , Etnicidade/genética , Genoma Humano
9.
Biomolecules ; 14(1)2023 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-38254619

RESUMO

Honey bees play a significant role in ecology, producing biologically active substances used to promote human health. However, unlike humans, the molecular markers indicating honey bee health remain unknown. Unfortunately, numerous reports of honey bee collapse have been documented. To identify health markers, we analyzed ten defense system genes in Apis mellifera ligustica honey bees from winter (Owb) and spring (Fb for foragers and Nb for newly emerged) populations sampled in February and late April 2023, respectively. We focused on colonies free from SBV and DWV viruses. Molecular profiling revealed five molecular markers of honey bee health. Of these, two seasonal molecular markers-domeless and spz genes-were significantly downregulated in Owb compared to Nb and Fb honey bees. One task-related marker gene, apid-1, was identified as being downregulated in Owb and Nb compared to Fb honey bees. Two recommended general health markers, SOD and defensin-2, were upregulated in honey bees. These markers require further testing across various honey bee subspecies in different climatic regions. They can diagnose bee health without colony intervention, especially during low-temperature months like winter. Beekeepers can use this information to make timely adjustments to nutrients or heating to prevent seasonal losses.


Assuntos
Temperatura Baixa , Ecologia , Humanos , Abelhas/genética , Animais , Estações do Ano , Calefação , Nutrientes
10.
Comput Biol Med ; 157: 106721, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36913852

RESUMO

The discovery of drugs to selectively remove disease-related cells is challenging in computer-aided drug design. Many studies have proposed multi-objective molecular generation methods and demonstrated their superiority using the public benchmark dataset for kinase inhibitor generation tasks. However, the dataset does not contain many molecules that violate Lipinski's rule of five. Thus, it remains unclear whether existing methods are effective in generating molecules violating the rule, such as navitoclax. To address this, we analysed the limitations of existing methods and propose a multi-objective molecular generation method with a novel parsing algorithm for molecular string representation and a modified reinforcement learning method for the efficient training of multi-objective molecular optimisation. The proposed model had success rates of 84% in GSK3b+JNK3 inhibitor generation and 99% in Bcl-2 family inhibitor generation tasks.


Assuntos
Antineoplásicos , Desenho de Fármacos , Algoritmos , Inibidores de Proteínas Quinases
11.
Org Biomol Chem ; 10(47): 9349-58, 2012 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-23108312

RESUMO

Nucleoside analogues having a boronic acid in place of the 3-hydroxyl group of deoxyribose have been synthesized. The synthesis of 3'-dihydroxyboryl-2',3'-dideoxyribose was based on asymmetric homologation of boronic esters with (dihalomethyl)lithium, beginning from a (silyloxymethyl)boronic ester. A change of chiral director is required before introduction of the second stereocenter, and the direct displacement of (S,S)-1,2-dicyclohexyl-1,2-ethanediol by (1S,2S,3R,5S)-pinanediol was used for this purpose. Coupling of the pinanediol ester of the 1-acetoxy-3-dioxyboryl-5-tert-butylsilyloxy deoxyribose analogue with silylated pyrimidine bases was accomplished with trimethylsilyl bromide. The boronic acid nucleoside analogues were not cytotoxic toward Hep G2 (human hepatocarcinoma) cells. Decomposition occurred over a period of several hours at 37 °C, pH 7.4, with liberation of free pyrimidine base.


Assuntos
Antineoplásicos/síntese química , Ácidos Borônicos/química , Nucleosídeos/síntese química , Pirimidinas/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Estrutura Molecular , Nucleosídeos/química , Pirimidinas/química , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico
12.
J Cheminform ; 14(1): 83, 2022 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-36494855

RESUMO

In this paper, a reinforcement learning model is proposed that can maximize the predicted binding affinity between a generated molecule and target proteins. The model used to generate molecules in the proposed model was the Stacked Conditional Variation AutoEncoder (Stack-CVAE), which acts as an agent in reinforcement learning so that the resulting chemical formulas have the desired chemical properties and show high binding affinity with specific target proteins. We generated 1000 chemical formulas using the chemical properties of sorafenib and the three target kinases of sorafenib. Then, we confirmed that Stack-CVAE generates more of the valid and unique chemical compounds that have the desired chemical properties and predicted binding affinity better than other generative models. More detailed analysis for 100 of the top scoring molecules show that they are novel ones not found in existing chemical databases. Moreover, they reveal significantly higher predicted binding affinity score for Raf kinases than for other kinases. Furthermore, they are highly druggable and synthesizable.

13.
Int Arch Allergy Immunol ; 154(1): 42-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20664276

RESUMO

BACKGROUND: Although several mechanisms underlying the asthma-obesity connection have been proposed, debates still remain. This study was to determine whether overweight is associated with a higher prevalence of atopy, asthma symptoms, airway obstruction, bronchial hyperresponsiveness (BHR) or biomarkers of inflammation in a sample of Korean adolescents. METHODS: We conducted a cross-sectional survey involving questionnaires, skin tests, spirometry and methacholine challenge tests among 717 adolescents from Seoul (South Korea). Overweight status was defined as a BMI greater than the local age- and gender-specific 85th percentile. RESULTS: Overweight subjects more frequently reported ever having wheezing (24.6 vs. 14.0%, p = 0.001) and wheezing in the previous 12 months (11.5 vs. 6.3%, p = 0.02) than normal-weight subjects, especially in boys. Atopy was more common among overweight adolescents than among those of normal weight (61.5 vs. 49.2%, p = 0.002), especially in boys (65.0 vs. 52.8%, p = 0.005). Overweight subjects had higher total WBC counts and eosinophil counts, especially boys. The presence of BHR was more common only among overweight girls (32.8 vs. 18.0%, p = 0.028). Overweight status was a significant risk factor for the presence of atopy (odds ratio = 1.49; 95% CI 1.06-2.10), after adjusting for various confounders by logistic regression analysis. CONCLUSIONS: An association was found between overweight status and both atopy and an increased prevalence of wheezing in adolescent Korean boys. These findings suggest that being overweight in puberty may be one of several risk factors responsible for atopy, BHR, and asthma symptoms.


Assuntos
Asma/epidemiologia , Hiper-Reatividade Brônquica/epidemiologia , Dermatite Atópica/epidemiologia , Hipersensibilidade/epidemiologia , Obesidade/epidemiologia , Adolescente , Índice de Massa Corporal , Estudos Transversais , Dermatite Atópica/diagnóstico , Eosinófilos , Feminino , Humanos , Imunoglobulina E/sangue , Contagem de Leucócitos , Masculino , Cloreto de Metacolina , Prevalência , República da Coreia/epidemiologia , Testes de Função Respiratória , Sons Respiratórios , Fatores Sexuais , Testes Cutâneos
14.
Exp Mol Med ; 53(6): 1092-1108, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34188179

RESUMO

Senescent cells exhibit a reduced response to intrinsic and extrinsic stimuli. This diminished reaction may be explained by the disrupted transmission of nuclear signals. However, this hypothesis requires more evidence before it can be accepted as a mechanism of cellular senescence. A proteomic analysis of the cytoplasmic and nuclear fractions obtained from young and senescent cells revealed disruption of nucleocytoplasmic trafficking (NCT) as an essential feature of replicative senescence (RS) at the global level. Blocking NCT either chemically or genetically induced the acquisition of an RS-like senescence phenotype, named nuclear barrier-induced senescence (NBIS). A transcriptome analysis revealed that, among various types of cellular senescence, NBIS exhibited a gene expression pattern most similar to that of RS. Core proteomic and transcriptomic patterns common to both RS and NBIS included upregulation of the endocytosis-lysosome network and downregulation of NCT in senescent cells, patterns also observed in an aging yeast model. These results imply coordinated aging-dependent reduction in the transmission of extrinsic signals to the nucleus and in the nucleus-to-cytoplasm supply of proteins/RNAs. We further showed that the aging-associated decrease in Sp1 transcription factor expression was critical for the downregulation of NCT. Our results suggest that NBIS is a modality of cellular senescence that may represent the nature of physiological aging in eukaryotes.


Assuntos
Senescência Celular , Proteômica , Núcleo Celular/metabolismo , Senescência Celular/genética , Regulação para Baixo
15.
J Am Chem Soc ; 132(11): 3642-3, 2010 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-20196537

RESUMO

S-adenosylmethionine (AdoMet or SAM)-dependent methyltransferases belong to a large and diverse family of group-transfer enzymes that perform vital biological functions on a host of substrates. Despite the progress in genomics, structural proteomics, and computational biology, functional annotation of methyltransferases remains a challenge. Herein, we report the synthesis and activity of a new AdoMet analogue functionalized with a ketone group. Using catechol O-methyltransferase (COMT, EC 2.1.1.6) and thiopurine S-methyltransferase (TPMT, EC 2.1.1.67) as model enzymes, this robust and readily accessible analogue displays kinetic parameters that are comparable to AdoMet and exhibits multiple turnovers with enzyme. More importantly, this AdoMet surrogate displays the same substrate specificity as the natural methyl donor. Incorporation of the ketone group allows for subsequent modification via bio-orthogonal labeling strategies and sensitive detection of the tagged ketone products. Hence, this AdoMet analogue expands the toolbox available to interrogate the biochemical functions of methyltransferases.


Assuntos
Biocatálise , Ensaios Enzimáticos/métodos , Cetonas/metabolismo , Metiltransferases/metabolismo , S-Adenosilmetionina/análogos & derivados , S-Adenosilmetionina/metabolismo , Animais , Humanos , Hidrazinas/química , Hidroxilaminas/química , Cetonas/química , S-Adenosilmetionina/química , Especificidade por Substrato
16.
Anticancer Drugs ; 21(4): 423-32, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20130467

RESUMO

Artemisinin is a plant-derived anti-malarial drug that has relatively low toxicity in humans and is activated by heme and/or intracellular iron leading to intracellular free radical formation. Interestingly, artemisinin has displayed anti-cancer activity, with artemisinin dimers being more potent than monomeric artemisinin. Intracellular iron uptake is regulated by the transferrin receptor (TfR), and the activity of artemisinin depends on the availability of iron. We examined the level of TfR in prostate cancer (PCa) tumor cells, synthesized two new artemisinin dimers, and evaluated the effect of dihydroartemisinin and artemisinin dimers, ON-2Py and 2Py, on proliferation and apoptosis in PCa cells. TfR was expressed in the majority of PCa bone and soft tissue metastases, all 24 LuCaP PCa xenografts, and PCa cell lines. After treatment with dihydroartemisinin, ON-2Py, or 2Py all PCa cell lines displayed dose-dependent decrease in cell number. 2Py was most effective in decreasing cell number. An increase in apoptotic events and growth arrest was observed in the C4-2 and LNCaP cell lines. Growth arrest was observed in PC-3 cells, but no significant change was observed in DU 145 cells. Treatment with 2Py resulted in a loss of the anti-apoptotic protein survivin in all four cell lines. 2Py treatment also decreased androgen receptor and prostate-specific antigen expression in C4-2 and LNCaP cells, with a concomitant loss of cell cycle regulatory proteins cyclin D1 and c-Myc. This study shows the potential use of artemisinin derivatives as therapeutic candidates for PCa and warrants the initiation of preclinical studies.


Assuntos
Antineoplásicos/uso terapêutico , Artemisininas/uso terapêutico , Neoplasias da Próstata/tratamento farmacológico , Apoptose/efeitos dos fármacos , Artemisininas/química , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Dimerização , Humanos , Ferro/metabolismo , Masculino , Neoplasias da Próstata/metabolismo , Receptores da Transferrina/metabolismo
17.
Biochim Biophys Acta ; 1783(12): 2287-93, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18761040

RESUMO

Importin-alpha is essential for classical nucleocytoplasmic transport of nuclear proteins. Here, we report that importin-alpha is cleaved by caspases during apoptosis, generating importin-alpha lacking an IBB domain. This truncated importin-alpha binds tightly to the MCM replication licensing factor and, thus, prevents its binding to chromatin and downregulates DNA synthesis. Together, our data reveal for the first time that a dying cell effectively salvages limited supplies of cellular energy to ensure an orderly process of its own demise by simultaneously downregulating nucleocytoplasmic protein transport and DNA synthesis. Strikingly, cells can achieve this multi-task process by simply cleaving-off a key nuclear import protein.


Assuntos
Apoptose/fisiologia , Caspases/metabolismo , Cromatina/metabolismo , DNA/biossíntese , Proteína 1 de Manutenção de Minicromossomo/metabolismo , alfa Carioferinas/metabolismo , Transporte Ativo do Núcleo Celular , Animais , Células CHO , Cricetinae , Cricetulus , Dano ao DNA , Replicação do DNA , Regulação para Baixo , Células HeLa , Humanos , Imunoprecipitação , Estrutura Terciária de Proteína , Transfecção , alfa Carioferinas/genética
18.
Biol Cell ; 100(12): 675-86, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18498247

RESUMO

BACKGROUND INFORMATION: PCNA (proliferating cell nuclear antigen) is required for a wide range of cellular functions, including DNA replication and damage repair. To be functional, PCNA must associate with the replication and repair foci. In addition, PCNA also mediates targeting of certain replication and repair proteins to these foci. However, the mechanism is not yet known by which PCNA is imported into the nucleus, and then localized to the replication and repair foci. RESULTS: We have found that an NLS (nuclear localization sequence) is present within the amino acid 101-120 segment of PCNA. An NLS-deleted PCNA was localized in the cytoplasm and showed 5-fold lower affinity for importin-beta than wild-type, suggesting that PCNA may be imported into the nucleus by importin-beta via its NLS. We previously reported that the functional unit of PCNA is a double trimer (as opposed to single homotrimer), and Lys-110 is essential for the formation of the double trimer complex [Naryzhny, Zhao and Lee (2005) J. Biol. Chem. 280, 13888-13894]. The present study shows that the substitution of Lys-110 within the NLS to an alanine residue did not affect its nuclear localization. However, the double-trimer-defective PCNA(K110A) was not localized at replication or repair foci. In contrast, the double-trimer-intact PCNA(K117A) mutant was targeted normally to replication and repair foci. Interestingly, in cells transfected with PCNA(K110A), but not PCNA(K117A), caspase-3-mediated chromosome fragmentation was activated. CONCLUSIONS: The present study suggests that the regulation of PCNA is intimately connected with that of DNA replication, repair and cell death signals, and raises the possibility that defects in the formation of the PCNA double-trimer complex can cause apoptosis.


Assuntos
Apoptose , Reparo do DNA , Replicação do DNA , Lisina/metabolismo , Mutação de Sentido Incorreto , Sinais de Localização Nuclear , Antígeno Nuclear de Célula em Proliferação/metabolismo , Sequência de Aminoácidos , Animais , Células CHO , Caspase 3/genética , Caspase 3/metabolismo , Núcleo Celular/genética , Núcleo Celular/metabolismo , Cricetinae , Cricetulus , Fragmentação do DNA , Células HeLa , Heterocromatina/metabolismo , Humanos , Dados de Sequência Molecular , Sinais de Localização Nuclear/química , Sinais de Localização Nuclear/genética , Antígeno Nuclear de Célula em Proliferação/química , Antígeno Nuclear de Célula em Proliferação/genética , Transporte Proteico
19.
Mol Neurobiol ; 56(5): 3819-3832, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30215158

RESUMO

TRPM2 a cation channel is also known to work as an enzyme that hydrolyzes highly reactive, neurotoxic ADP-ribose (ADPR). Although ADPR is hydrolyzed by NUT9 pyrophosphatase in major organs, the enzyme is defective in the brain. The present study questions the role of TRPM2 in the catabolism of ADPR in the brain. Genetic ablation of Trpm2 results in the disruption of ADPR catabolism that leads to the accumulation of ADPR and reduction in AMP. Trpm2-/- mice elicit the reduction in autophagosome formation in the hippocampus. Trpm2-/- mice also show aggregations of proteins in the hippocampus, aberrant structural changes and neuronal connections in synapses, and neuronal degeneration. Trpm2-/- mice exhibit learning and memory impairment, enhanced neuronal intrinsic excitability, and imbalanced synaptic transmission. These results respond to long-unanswered questions regarding the potential role of the enzymatic function of TRPM2 in the brain, whose dysfunction evokes protein aggregation. In addition, the present finding answers to the conflicting reports such as neuroprotective or neurodegenerative phenotypes observed in Trpm2-/- mice.


Assuntos
Adenosina Difosfato Ribose/metabolismo , Autofagia , Encéfalo/metabolismo , Deleção de Genes , Agregados Proteicos , Canais de Cátion TRPM/deficiência , Animais , Cognição , Hipocampo/metabolismo , Hidrólise , Memória , Camundongos Endogâmicos C57BL , Camundongos Knockout , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Plasticidade Neuronal , Neurônios/metabolismo , Transmissão Sináptica , Canais de Cátion TRPM/metabolismo
20.
Anal Chem ; 80(10): 3882-9, 2008 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-18419136

RESUMO

Isoaspartate formation is a ubiquitous post-translation modification arising from spontaneous asparagine deamidation or aspartate isomerization. The formation of isoaspartate inserts a methylene group into the protein backbone, generating a "kink", and may drastically alter protein structure and function, thereby playing critical roles in a myriad of biological processes, human diseases, and protein pharmaceutical development. Herein, we report a chemo-enzymatic detection method for the isoaspartate protein, which in particular allows the affinity enrichment of isoaspartate-containing proteins. In the initial step, protein isoaspartate methyltransferase selectively converts isoaspartates into the corresponding methyl esters. Subsequently, the labile methyl ester is trapped by strong nucleophiles in aqueous solutions, such as hydrazines to form hydrazides. The stable hydrazide products can be analyzed by standard proteomic techniques, such as matrix-assisted laser desorption ionization and electrospray ionization mass spectrometry. Furthermore, the chemical trapping step allows us to introduce several tagging strategies for product identification and quantification, such as UV-vis and fluorescence detection through a dansyl derivative. Most significantly, the hydrazide product can be enriched by affinity chromatography using aldehyde resins, thus drastically reducing sample complexity. Our method hence represents the first technique for the affinity enrichment of isoaspartyl proteins and should be amendable to the systematic and comprehensive characterization of isoaspartate, particularly in complex systems.


Assuntos
Hidrazinas/química , Ácido Isoaspártico/análise , Proteína D-Aspartato-L-Isoaspartato Metiltransferase/química , Proteínas/química , Cromatografia de Afinidade , Espectrometria de Fluorescência , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
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