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1.
Cancer Cell Int ; 20: 355, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760222

RESUMO

BACKGROUND: Esophageal cancer is one of the most common cancers worldwide with poor prognosis and high mortality. The transcription factor SNAI1, encoding Snail1, is important for metastatic progression in esophageal cancer whereas the microRNA (miRNA)-203 has been shown to function as an inhibitor of metastasis in EC. The Snail1 protein is stabilized in EC partially by the deubiquitinating enzyme USP26; however, how USP26 is regulated is not completely known. METHODS: Expression of SNAI1 and USP26 messenger RNA (mRNA) and miR-203 was performed in datasets within The Cancer Genome Atlas and Gene Expression Omnibus, respectively. Expression of Snail1 and USP26 protein and miR-203 was determined in the normal esophageal cell line HET-1A and EC cell lines Kyse150 and TE-1 using western blot and quantitative polymerase chain reaction, respectively. TargetScan was used for in situ prediction of miR-203 targets and in vitro heterologous reporter assays using the wild-type and miR-203 seed mutant of the 3' Untranslated region (UTR) of USP26 were used to investigate whether USP26 is a target of miR-203. Effects of increasing miR-203 using MIR203A/5P mimic on USP26 and Snail1 in the HET-1A, Kyse150 and TE-1 cell lines were performed using western blot and cycloheximide-based protein stability analysis. Effects of modulating miR-203 in Kyse150 and TE-1 cell lines on in vitro pro-metastatic effects were analyzed by invasion assay, scratch wound-healing assay, and chemosensitivity to 5-fluoruracil (5-FU). In vivo lung metastasis assay was used to study the effect of modulating miR-203 in Kyse150 cells. RESULTS: SNAI1 mRNA and HSA/MIR203 was higher and lower, respectively, in EC patients compared to tumor-adjacent normal tissues. No changes in expression of USP26 mRNA were observed in these datasets. MIR/203 expression was downregulated whereas protein expression of both Snail1 and USP26 were higher in EC cell lines Kyse150 and TE-1 compared to normal esophageal cell line HET-1A. USP26 was predicted as a potential target of miR-203 by TargetScan Release 2.0. Reporter assays confirmed USP26 as a target of miR-203 in the EC cell lines. Transfection of EC cell lines with MIR203 mimic decreased USP26 protein expression and Snail1 protein stability indicating the ability of miR-203 to regulate Snail1 protein levels via USP26. Exogenous increase in miR-203 in the EC cell lines significantly inhibited Snail-1 mediated in vitro pro-metastatic function of invasion, wound-healing, and increased chemosensitivity to 5-FU. Finally, overexpression of miR-203 inhibited in vivo lung metastasis of Kyse150 cells, which was reversed following overexpression of USP26, indicating a direct role of miR-203-mediated regulation of USP26 in metastatic progression of EC. CONCLUSIONS: Cumulatively, these results establish an important mechanism by which decrease in miR-203 expression potentiates metastatic progression in EC via USP26-mediated stabilization of Snail1. Hence, miR-203 can serve as a biomarker of metastasis in EC and is a potential target for therapeutic intervention in EC.

2.
Bioorg Med Chem ; 27(4): 579-588, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30626555

RESUMO

The antioxidant natural product sulforaphane (SFN) is an oil with poor aqueous and thermal stability. Recent work with SFN has sought to optimize methods of formulation for oral and topical administration. Herein we report the design of new analogs of SFN with the goal of improving stability and drug-like properties. Lead compounds were selected based on potency in a cellular screen and physicochemical properties. Among these, 12 had good aqueous solubility, permeability and long-term solid-state stability at 23 °C. Compound 12 also displayed comparable or better efficacy in cellular assays relative to SFN and had in vivo activity in a mouse cigarette smoke challenge model of acute oxidative stress.


Assuntos
Antioxidantes/farmacologia , Ciclobutanos/farmacologia , Descoberta de Drogas , Isotiocianatos/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Antioxidantes/síntese química , Antioxidantes/farmacocinética , Linhagem Celular , Ciclobutanos/síntese química , Ciclobutanos/farmacocinética , Expressão Gênica , Heme Oxigenase-1/genética , Humanos , Isotiocianatos/síntese química , Isotiocianatos/farmacocinética , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Camundongos Endogâmicos C57BL , Estrutura Molecular , Estresse Oxidativo/efeitos dos fármacos , Ratos , Solubilidade , Relação Estrutura-Atividade , Sulfóxidos , Tiocarbamatos/síntese química , Tiocarbamatos/farmacocinética , Tiocarbamatos/farmacologia
3.
Opt Express ; 25(10): 11867-11893, 2017 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-28788746

RESUMO

For the first time, the angular non-critical phase-matching (A-NCPM) second-harmonic-generation (SHG) characteristics of a family of monoclinic oxoborate crystals, RECa4O(BO3)3 (RECOB, RE = Tm, Y, Gd, Sm, Nd and La), were comprehensively investigated. For all of the realizable A-NCPM SHG styles, the feature parameters including PM wavelength, angular, wavelength and temperature acceptance bandwidths, have been derived from the theory and verified by the experiments. We discovered that the closer the ion radius between RE3+ and Ca2+, the smaller the birefringence, and the better the A-NCPM SHG properties. As a result, for the Type-I SHG on Y-axis which has the largest effective nonlinear optical coefficient (deff) among the three realizable A-NCPM styles, NdCOB crystal presents the longest PM wavelength (927 nm), the largest angular acceptance bandwidth (Δθ⋅l1/2 = 84.3 mrad·cm1/2, Δϕ⋅l1/2 = 58.8 mrad·cm1/2), and the broadest wavelength acceptance bandwidth (8.7 nm). This discovery will contribute to the design of new NCPM materials, at the same time the parameter formula will be helpful for the theoretical prediction of NCPM performance.

4.
Nat Chem Biol ; 11(11): 878-86, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26436839

RESUMO

Neomorphic mutations in isocitrate dehydrogenase 1 (IDH1) are driver mutations in acute myeloid leukemia (AML) and other cancers. We report the development of new allosteric inhibitors of mutant IDH1. Crystallographic and biochemical results demonstrated that compounds of this chemical series bind to an allosteric site and lock the enzyme in a catalytically inactive conformation, thereby enabling inhibition of different clinically relevant IDH1 mutants. Treatment of IDH1 mutant primary AML cells uniformly led to a decrease in intracellular 2-HG, abrogation of the myeloid differentiation block and induction of granulocytic differentiation at the level of leukemic blasts and more immature stem-like cells, in vitro and in vivo. Molecularly, treatment with the inhibitors led to a reversal of the DNA cytosine hypermethylation patterns caused by mutant IDH1 in the cells of individuals with AML. Our study provides proof of concept for the molecular and biological activity of novel allosteric inhibitors for targeting different mutant forms of IDH1 in leukemia.


Assuntos
Di-Hidropiridinas/farmacologia , Inibidores Enzimáticos/farmacologia , Isocitrato Desidrogenase/antagonistas & inibidores , Leucemia Mieloide Aguda/tratamento farmacológico , Pirazóis/farmacologia , Regulação Alostérica , Sítio Alostérico , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ilhas de CpG , Cristalografia por Raios X , Citosina/química , Citosina/metabolismo , Metilação de DNA/efeitos dos fármacos , Di-Hidropiridinas/química , Di-Hidropiridinas/farmacocinética , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacocinética , Granulócitos/efeitos dos fármacos , Granulócitos/enzimologia , Granulócitos/patologia , Humanos , Isocitrato Desidrogenase/química , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Cinética , Leucemia Mieloide Aguda/enzimologia , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Masculino , Camundongos , Modelos Moleculares , Mutação , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/enzimologia , Células-Tronco Neoplásicas/patologia , Cultura Primária de Células , Ligação Proteica , Pirazóis/química , Pirazóis/farmacocinética , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Opt Lett ; 41(24): 5823-5826, 2016 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-27973513

RESUMO

For KH2PO4 (KDP) crystal, the phase-matching directions of type-II second-harmonic generation (SHG) and type-II third-harmonic generation (THG) for 1 µm lasers are almost identical, i.e., at (θ=60°, φ=0°) around. Utilizing this special property, we designed a THG converter based on one KDP crystal. A quarter-wave (λ/4) plate was used to adjust the polarization of the SHG wave, and a round-trip optical path was used to realize the SHG and THG procedures successively. When the fundamental light source was a 1064 nm, 40 ps pulse laser, the maximum THG output at 355 nm was 1.13 mJ, and the highest THG conversion efficiency was 30.7%. To the best of our knowledge, this is the first time that the cascaded frequency upconversion processes are realized in one bulk nonlinear optical crystal. This method possesses many advantages for future applications, including high efficiency, a wide-working waveband, low cost, and applicability to many other crystals such as DKDP, ADP, DADP, and GdxY1-xCOB.

6.
Mol Pharmacol ; 88(6): 1011-23, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26438213

RESUMO

Activation of the inositol-requiring enzyme-1 alpha (IRE1α) protein caused by endoplasmic reticulum stress results in the homodimerization of the N-terminal endoplasmic reticulum luminal domains, autophosphorylation of the cytoplasmic kinase domains, and conformational changes to the cytoplasmic endoribonuclease (RNase) domains, which render them functional and can lead to the splicing of X-box binding protein 1 (XBP 1) mRNA. Herein, we report the first crystal structures of the cytoplasmic portion of a human phosphorylated IRE1α dimer in complex with (R)-2-(3,4-dichlorobenzyl)-N-(4-methylbenzyl)-2,7-diazaspiro(4.5)decane-7-carboxamide, a novel, IRE1α-selective kinase inhibitor, and staurosporine, a broad spectrum kinase inhibitor. (R)-2-(3,4-dichlorobenzyl)-N-(4-methylbenzyl)-2,7-diazaspiro(4.5)decane-7-carboxamide inhibits both the kinase and RNase activities of IRE1α. The inhibitor interacts with the catalytic residues Lys599 and Glu612 and displaces the kinase activation loop to the DFG-out conformation. Inactivation of IRE1α RNase activity appears to be caused by a conformational change, whereby the αC helix is displaced, resulting in the rearrangement of the kinase domain-dimer interface and a rotation of the RNase domains away from each other. In contrast, staurosporine binds at the ATP-binding site of IRE1α, resulting in a dimer consistent with RNase active yeast Ire1 dimers. Activation of IRE1α RNase activity appears to be promoted by a network of hydrogen bond interactions between highly conserved residues across the RNase dimer interface that place key catalytic residues poised for reaction. These data implicate that the intermolecular interactions between conserved residues in the RNase domain are required for activity, and that the disruption of these interactions can be achieved pharmacologically by small molecule kinase domain inhibitors.


Assuntos
Endorribonucleases/antagonistas & inibidores , Endorribonucleases/metabolismo , Inibidores de Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Linhagem Celular Tumoral , Cristalização , Endorribonucleases/química , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Humanos , Conformação Proteica/efeitos dos fármacos , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/química , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína
7.
Opt Express ; 23(3): 2163-73, 2015 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-25836087

RESUMO

As excellent nonlinear optical (NLO) crystals, YCa(4)O(BO(3))(3) (YCOB) and GdCa(4)O(BO(3))(3) (GdCOB) have been paid much attention since their first appearance in 1990's. From that time to now, almost all of related researches and applications have focused on their type-I phase-matching (PM) configurations which possess large effective NLO coefficient (d(eff)). In this paper, type-II second-harmonic-generation (SHG) properties of these two crystals are reported, including PM curve, d(eff), angular acceptance and walk-off angle. Both of the type-II SHG experiments for 1064 and 1320 nm have indicated that the optimum directions which have maximum d(eff) locate in the second octant, i.e. (90° < θ< 180°, 0° < ϕ < 90°). For a (112°, 81.3°)-cut, 24 mm long YCOB crystal, the largest type-II SHG conversion efficiency of a 1064 nm Nd:YAG pico-second laser is 55%, which reaches the same level of the optimum type-I sample. To our knowledge this is the first time that type-II SHG performance of YCOB and GdCOB crystals is investigated intensively. Our research has shown that the smaller d(eff) of type-II PM can be compensated by its larger angular acceptance and less beam walk-off. The same level SHG conversion efficiency implies for such type crystals the type-II components have the potential to replace type-I ones and obtain important NLO applications in the future.

8.
Sci Total Environ ; 927: 172311, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38599416

RESUMO

Flotation technology is widely utilized to remove emulsified oil droplets from Produced water. Organic acid adsorption on the oil droplet surface affects bubble attachment, reducing oil removal efficiency. This investigation exploited the principle of similar dissolution to synthesize condensate bubbles (CB). The surface properties of oil droplets and CB and air bubbles (AB) were appraised using FTIR, zeta potential, interfacial tension, and contact angle measurements. The research also investigated the effects of acetic acids (AA) on the adhesion of oil droplets to AB and CB along with the underlying mechanism via the Extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) interaction theory and the Stefan-Reynolds model of liquid film thinning, integrated with adhesion times. Flotation efficiency and kinetic dissimilarities between AB and CB were also examined. The results indicated that CB exhibits superior lipophilic hydrophobicity compared to AB, reduced induction and spreading times upon oil droplet attachment, and maximized oil removal efficiency. Furthermore, CB could mitigate the impact of AA on adhesion. The interaction barriers between CB and oil droplets were minimal, and the thinning rate of the hydration film was quicker than in AB. The conventional first-order model proved effective in fitting the AB flotation, whereas a delay constant was applied to the model of the CB flotation rate.

9.
Biochemistry ; 52(26): 4563-77, 2013 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-23731180

RESUMO

The human, cytosolic enzyme isocitrate dehydrogenase 1 (IDH1) reversibly converts isocitrate to α-ketoglutarate (αKG). Cancer-associated somatic mutations in IDH1 result in a loss of this normal function but a gain in a new or neomorphic ability to convert αKG to the oncometabolite 2-hydroxyglutarate (2HG). To improve our understanding of the basis for this phenomenon, we have conducted a detailed kinetic study of wild-type IDH1 as well as the known 2HG-producing clinical R132H and G97D mutants and mechanistic Y139D and (newly described) G97N mutants. In the reductive direction of the normal reaction (αKG to isocitrate), dead-end inhibition studies suggest that wild-type IDH1 goes through a random sequential mechanism, similar to previous reports on related mammalian IDH enzymes. However, analogous experiments studying the reductive neomorphic reaction (αKG to 2HG) with the mutant forms of IDH1 are more consistent with an ordered sequential mechanism, with NADPH binding before αKG. This result was further confirmed by primary kinetic isotope effects for which saturating with αKG greatly reduced the observed isotope effect on (D)(V/K)NADPH. For the mutant IDH1 enzyme, the change in mechanism was consistently associated with reduced efficiencies in the use of αKG as a substrate and enhanced efficiencies using NADPH as a substrate. We propose that the sum of these kinetic changes allows the mutant IDH1 enzymes to reductively trap αKG directly into 2HG, rather than allowing it to react with carbon dioxide and form isocitrate, as occurs in the wild-type enzyme.


Assuntos
Neoplasias Encefálicas/enzimologia , Citosol/enzimologia , Isocitrato Desidrogenase , Proteínas Mutantes , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Cristalografia por Raios X , Glutaratos/química , Glutaratos/metabolismo , Humanos , Isocitrato Desidrogenase/química , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Isocitratos/química , Ácidos Cetoglutáricos/química , Ácidos Cetoglutáricos/metabolismo , Cinética , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Mutação
10.
Prostaglandins Other Lipid Mediat ; 104-105: 25-31, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23434473

RESUMO

Soluble epoxide hydrolase (sEH, EPHX2) metabolizes eicosanoid epoxides, including epoxyeicosatrienoic acids (EETs) to the corresponding dihydroxyeicosatrienoic acids (DHETs), and leukotoxin (LTX) to leukotoxin diol (LTX diol). EETs, endothelium-derived hyperpolarizing factors, exhibit potentially beneficial properties, including anti-inflammatory effects and vasodilation. A novel, potent, selective inhibitor of recombinant human, rat and mouse sEH, GSK2256294A, exhibited potent cell-based activity, a concentration-dependent inhibition of the conversion of 14,15-EET to 14,15-DHET in human, rat and mouse whole blood in vitro, and a dose-dependent increase in the LTX/LTX diol ratio in rat plasma following oral administration. Mice receiving 10 days of cigarette smoke exposure concomitant with oral administration of GSK2256294A exhibited significant, dose-dependent reductions in pulmonary leukocytes and keratinocyte chemoattractant (KC, CXCL1) levels. Mice receiving oral administration of GSK2256294A following 10 days of cigarette smoke exposure exhibited significant reductions in pulmonary leukocytes compared to vehicle-treated mice. These data indicate that GSK2256294A attenuates cigarette smoke-induced inflammation by both inhibiting its initiation and/or maintenance and promoting its resolution. Collectively, these data indicate that GSK2256294A would be an appropriate agent to evaluate the role of sEH in clinical studies, for example in diseases where cigarette smoke is a risk factor, such as chronic obstructive pulmonary disease (COPD) and cardiovascular disease.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Cicloexilaminas/farmacologia , Epóxido Hidrolases/antagonistas & inibidores , Leucócitos/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Triazinas/farmacologia , Ácido 8,11,14-Eicosatrienoico/análogos & derivados , Ácido 8,11,14-Eicosatrienoico/metabolismo , Administração Oral , Adulto , Animais , Quimiocina CXCL1/biossíntese , Relação Dose-Resposta a Droga , Epóxido Hidrolases/metabolismo , Exotoxinas/metabolismo , Feminino , Humanos , Inflamação/enzimologia , Inflamação/etiologia , Inflamação/patologia , Inflamação/prevenção & controle , Contagem de Leucócitos , Leucócitos/metabolismo , Leucócitos/patologia , Pulmão/enzimologia , Pulmão/patologia , Masculino , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ácidos Esteáricos/metabolismo , Poluição por Fumaça de Tabaco/efeitos adversos
11.
Biochemistry ; 51(25): 5198-211, 2012 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-22657152

RESUMO

ATP citrate lyase (ACL) catalyzes an ATP-dependent biosynthetic reaction which produces acetyl-coenzyme A and oxaloacetate from citrate and coenzyme A (CoA). Studies were performed with recombinant human ACL to ascertain the nature of the catalytic phosphorylation that initiates the ACL reaction and the identity of the active site residues involved. Inactivation of ACL by treatment with diethylpyrocarbonate suggested the catalytic role of an active site histidine (i.e., His760), which was proposed to form a phosphohistidine species during catalysis. The pH-dependence of the pre-steady-state phosphorylation of ACL with [γ-(33)P]-ATP revealed an ionizable group with a pK(a) value of ~7.5, which must be unprotonated for the catalytic phosphorylation of ACL to occur. Mutagenesis of His760 to an alanine results in inactivation of the biosynthetic reaction of ACL, in good agreement with the involvement of a catalytic histidine. The nature of the formation of the phospho-ACL was further investigated by positional isotope exchange using [γ-(18)O(4)]-ATP. The ß,γ-bridge to nonbridge positional isotope exchange rate of [γ-(18)O(4)]-ATP achieved its maximal rate of 14 s(-1) in the absence of citrate and CoA. This rate decreased to 5 s(-1) when citrate was added, and was found to be 10 s(-1) when both citrate and CoA were present. The rapid positional isotope exchange rates indicated the presence of one or more catalytically relevant, highly reversible phosphorylated intermediates. Steady-state measurements in the absence of citrate and CoA showed that MgADP was produced by both wild type and H760A forms of ACL, with rates at three magnitudes lower than that of k(cat) for the full biosynthetic reaction. The ATPase activity of ACL, along with the small yet significant positional isotope exchange rate observed in H760A mutant ACL (~150 fold less than wild type), collectively suggested the presence of a second, albeit unproductive, phosphoryl transfer in ACL. Mathematical analysis and computational simulation suggested that the desorption of MgADP at a rate of ~7 s(-1) was the rate-limiting step in the biosynthesis of AcCoA and oxaloacetate.


Assuntos
ATP Citrato (pro-S)-Liase/química , ATP Citrato (pro-S)-Liase/farmacocinética , ATP Citrato (pro-S)-Liase/genética , Acetilcoenzima A/biossíntese , Biocatálise , Domínio Catalítico/genética , Sequência Conservada , Medição da Troca de Deutério , Histidina/química , Histidina/genética , Histidina/metabolismo , Humanos , Mutação , Ácido Oxaloacético/metabolismo , Fosforilação
12.
Mol Biol Rep ; 39(2): 1869-76, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21660473

RESUMO

The study was conducted to evaluate the effects of different starch sources on Bacillus spp. in intestinal tract and expression of intestinal development related genes of weanling piglets. Twenty-eight PIC male piglets were divided into four homogeneous groups according to initial body weight (similar birth and parity, weaned at 21 ± 1.5 days). Diets for the four treatments consisted of corn starch, wheat starch, tapioca starch and pea starch with the determined ratio for amylose to amylopectin of 0.21, 0.24, 0.12 and 0.52 respectively. Real-time quantitative polymerase chain reaction was applied to: (1) detect genomic DNA of Bacillus and to quantify the number of Bacillus in the intestinal tract chyme of piglets with the primers and probe which designed based on the 16S rRNA sequences of maximum species of Bacillus on GenBank; (2) measure the mRNA level of glucagon-like peptide 2 (GLP-2), insulin-like growth factors 1 (IGF-1) and epidermal growth factor (EGF) in duodenum, jejunum and ileum. Results showed that the number of Baciilus and the percentage based on all bacteria in the whole intestinal content of piglets fed pea starch was highest in all groups (P < 0.05). There was no significant differance on copy numbers for all bacteria and Bacillus in the whole intestinal tract of piglets between the corn starch group and wheat starch group (P > 0.05). In addition, the expression level of GLP-2, IGF-1 mRNA in jejunum and ileum of pea starch treatment (the high amylose/amylopectin ratio) were increased while the tapioca starch decreased their mRNA level significantly compared to other three treatments (P < 0.05). There was no significant difference for the mRNA level of EGF in each group. The present study revealed that high amylose/amylopectin ratio of starches significantly enhanced the numbers of Bacillus in all segments of intestine and the mRNA level of intestinal development related genes.


Assuntos
Bacillus/efeitos dos fármacos , Carboidratos da Dieta/farmacologia , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Intestinos/microbiologia , Amido/farmacologia , Sus scrofa/genética , Sus scrofa/microbiologia , Análise de Variância , Animais , Bacillus/genética , Primers do DNA/genética , Fator de Crescimento Epidérmico/metabolismo , Peptídeo 2 Semelhante ao Glucagon/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Mucosa Intestinal/metabolismo , Masculino , Reação em Cadeia da Polimerase em Tempo Real
13.
Biochemistry ; 50(21): 4804-12, 2011 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-21524095

RESUMO

Heterozygously expressed single-point mutations in isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2, respectively) render these dimeric enzymes capable of producing the novel metabolite α-hydroxyglutarate (αHG). Accumulation of αHG is used as a biomarker for a number of cancer types, helping to identify tumors with similar IDH mutations. With IDH1, it has been shown that one role of the mutation is to increase the rate of conversion from αKG to αHG. To improve our understanding of the function of this mutation, we have detailed the kinetics of the normal (isocitrate to αKG) and neomorphic (αKG to αHG) reactions, as well as the coupled conversion of isocitrate to αHG. We find that the mutant IDH1 is very efficient in this coupled reaction, with the ability to form αHG from isocitrate and NADP(+). The wild type/wild type IDH1 is also able to catalyze this conversion, though it is much more sensitive to concentrations of isocitrate. This difference in behavior can be attributed to the competitive binding between isocitrate and αKG, which is made more favorable for αKG by the neomorphic mutation at arginine 132. Thus, each partial reaction in the heterodimer is functionally isolated from the other. To test whether there is a cooperative effect resulting from the two subunits being in a dimer, we selectively inactivated each subunit with a secondary mutation in the NADP/H binding site. We observed that the remaining, active subunit was unaffected in its associated activity, reinforcing the notion of each subunit being functionally independent. This was further demonstrated using a monomeric form of IDH from Azotobacter vinelandii, which can be shown to gain the same neomorphic reaction when a homologous mutation is introduced into that protein.


Assuntos
Glutaratos/metabolismo , Isocitrato Desidrogenase/fisiologia , Mutação , Cromatografia Líquida de Alta Pressão , Isocitrato Desidrogenase/genética , Modelos Moleculares , Mutagênese , Espectrometria de Massas em Tandem
14.
Protein Expr Purif ; 73(2): 167-76, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20457255

RESUMO

Phosphoinositide 3-kinases have been targeted for therapeutic research because they are key components of a cell signaling cascade controlling proliferation, growth, and survival. Direct activation of the PI3Kalpha pathway contributes to the development and progression of solid tumors in breast, endometrial, colon, ovarian, and gastric cancers. In the context of a drug discovery effort, the availability of a robust crystallographic system is a means to understand the subtle differences between ATP competitive inhibitor interactions with the active site and their selectivity against other PI3Kinase enzymes. To generate a suitable recombinant design for this purpose, a p85alpha-p110alpha fusion system was developed which enabled the expression and purification of a stoichiometrically homogeneous, constitutively active enzyme for structure determination with potent ATP competitive inhibitors (Raha et al., in preparation) [56]. This approach has yielded preparations with activity and inhibition characteristics comparable to those of the full-length PI3Kalpha from which X-ray diffracting crystals were grown with inhibitors bound in the active site.


Assuntos
Classe II de Fosfatidilinositol 3-Quinases/metabolismo , Cristalografia por Raios X , Inibidores Enzimáticos/farmacologia , Trifosfato de Adenosina/metabolismo , Animais , Fusão Gênica Artificial , Baculoviridae/metabolismo , Sítios de Ligação , Células Cultivadas , Classe II de Fosfatidilinositol 3-Quinases/química , Classe II de Fosfatidilinositol 3-Quinases/genética , Classe Ia de Fosfatidilinositol 3-Quinase/genética , Desenho de Fármacos , Concentração Inibidora 50 , Modelos Moleculares , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo , Spodoptera/citologia , Spodoptera/metabolismo , Difração de Raios X
15.
J Cardiothorac Surg ; 15(1): 212, 2020 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-32762705

RESUMO

BACKGROUND: To study the clinical manifestations and advantages of open-heart surgery and echocardiographic transthoracic or percutaneous closure with secundum atrial septal defect (ASD). The surgeon's learning curve was also analyzed. METHODS: In all, 115 consecutive patients with ASD from May 2013 to May 2019 were enrolled. According to the operative procedure, patients were divided into three groups: group one (open repair group) (n = 24), where patients underwent ASD repair (ASDR) under cardiopulmonary bypass (CPB); group two (closed surgical device closure group) (n = 69), where patients (six patients ≤1 y and sixteen ≤10 kg) underwent transthoracic ASD occlusion under transesophageal echocardiographic (TEE) guidance; and group three (transcatheter occlusion group) (n = 22), where patients underwent percutaneous ASD occlusion under echocardiography. The clinical features and results of each group were analyzed. All patients were telephonically followed-up after 3 months. RESULTS: All the three methods treating ASD were successfully performed in our hospital. It was also a typical developing history of congenital heart disease (CHD) surgery in China. One patient in the group two was transferred to emergency surgery for occluder retrieval and CPB-ASDR. Eight patients experienced failed transthoracic or percutaneous occlusion, two of whom underwent unsuccessful percutaneous closure at another hospital. Two patients each in the groups two and three were intraoperatively converted to CPB-ASDR. Two patient in the group three was converted to transthoracic occlusion surgery. All patients were discharged without any residual shunt. The three-month follow-up also did not show any residual shunt and occluder displacement. CONCLUSION: In low-weight, infants, or huge ASDs with suitable rim for device occlusion, transthoracic ASD closure was successfully performed. Based on knowledge of ASD anatomy and skilled transthoracic occlusion of ASD, surgeons can perform percutaneous occlusion of ASD under echocardiographic guidance.


Assuntos
Procedimentos Cirúrgicos Cardíacos/métodos , Ecocardiografia Transesofagiana , Ecocardiografia , Comunicação Interatrial/diagnóstico por imagem , Comunicação Interatrial/cirurgia , Adolescente , Adulto , Peso Corporal , Ponte Cardiopulmonar , Criança , Pré-Escolar , China , Feminino , Humanos , Lactente , Curva de Aprendizado , Masculino , Dispositivo para Oclusão Septal , Resultado do Tratamento , Adulto Jovem
16.
SLAS Discov ; 24(2): 175-189, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30383469

RESUMO

Nrf2, a master regulator of the phase II gene response to stress, is kept at low concentrations in the cell through binding to Keap1, an adaptor protein for the Cul3 ubiquitin ligase complex. To identify Nrf2 activators, two separate time-resolved fluorescence resonance energy transfer (TR-FRET) assays were developed to monitor the binding of Nrf2-Keap1 and Cul3-Keap1, respectively. The triterpenoid, 1-[2-cyano-3-,12-dioxooleana-1,9(11)-dien-28-oyl] imidazole (CDDO-Im) and its analogs, exhibited approximately 100-fold better potency in the Cul3-Keap1 assay than in the Nrf2-Keap1 assay, and this difference was more profound at 37 °C than at room temperature in the Nrf2-Keap1 assay, but this phenomenon was not observed in the Cul3-Keap1 assay. A full diversity screen of approximately 2,200,000 GSK compounds was run with the Cul3-Keap1 TR-FRET assay and multiple chemical series were identified and characterized.


Assuntos
Proteínas Culina/metabolismo , Transferência Ressonante de Energia de Fluorescência/métodos , Ensaios de Triagem em Larga Escala/métodos , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Células HEK293 , Humanos , Concentração Inibidora 50 , Cinética , Ligação Proteica , Temperatura , Fatores de Tempo
17.
Chin Med J (Engl) ; 131(18): 2179-2184, 2018 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-30203792

RESUMO

BACKGROUND: Arterial grafts had better mid-term and long-term patency than saphenous vein grafts in coronary artery bypass grafting (CABG). We summarized our experience with total arterial off-pump coronary artery bypass grafting (OPCAB) and assessed the early clinical results, surgical complications, and follow-up. METHODS: From January 2007 to May 2017, 508 coronary artery disease patients undergoing total arterial OPCAB were enrolled. Clinical features, approaches, outcomes of surgical treatments, and follow-up data of these patients were studied retrospectively. A total of 122 patients underwent single left internal mammary artery (IMA)-left anterior descending artery grafts, whereas the other 386 patients underwent multiple vessel grafts. RESULTS: The average distal anastomosis was 2.34 ± 0.97 (range: 1-4). All the patients were discharged from hospital except one died. A total of 457 (90.32%) patients were followed up. In the 4-, 7-, and 10-year follow-up groups, the rate of death from any cause was 1.19%, 6.47%, and 10.67%; rate of cardiac death was 0.60%, 2.88%, and 3.33%; rate of repeat revascularization was 0.00%, 3.60%, and 8.67%; rate of ischemic symptoms was 1.79%, 7.91%, and 11.33%; and incidence of stroke was 2.38%, 4.32%, and 6.67%, respectively. Poor medication adherence was observed in 9.38% of the follow-up population. CONCLUSIONS: Total arterial OPCAB with bilateral IMA, radial artery, and right gastroepiploic artery grafting yielded satisfactory early and midterm outcomes in this patient group, without a significant increase in early mortality or morbidity. Moreover, the long-term outcomes are also positive.


Assuntos
Angiografia Coronária , Ponte de Artéria Coronária sem Circulação Extracorpórea , Adulto , Idoso , Idoso de 80 Anos ou mais , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Grau de Desobstrução Vascular
18.
J Phys Condens Matter ; 30(2): 02LT01, 2018 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-29160770

RESUMO

Cascaded longitudinal stimulated Raman scattering (LSRS) and the frequency doubling process are reported for the first time. When potassium dihydrogen phosphate (KDP) crystals are used as the type I and type II frequency doublers of picosecond, focused 1064 nm laser pulses, strong LSRS effects are observed. Three new laser spectrum lines appeared successively, i.e. at 558.9, 588.9 and 622.1 nm, and were excited by the frequency doubling laser at 532 nm. Second- and third-order nonlinear optical frequency conversions were achieved in a single KDP crystal. The near-infrared light was thus converted into a new spectra laser spanning the green-to-red spectral range.

19.
SLAS Discov ; 23(1): 34-46, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28957646

RESUMO

A persistent problem in early small-molecule drug discovery is the frequent lack of rank-order correlation between biochemical potencies derived from initial screens using purified proteins and the diminished potency and efficacy observed in subsequent disease-relevant cellular phenotypic assays. The introduction of the cellular thermal shift assay (CETSA) has bridged this gap by enabling assessment of drug target engagement directly in live cells based on ligand-induced changes in protein thermal stability. Initial success in applying CETSA across multiple drug target classes motivated our investigation into replacing the low-throughput, manually intensive Western blot readout with a quantitative, automated higher-throughput assay that would provide sufficient capacity to use CETSA as a primary hit qualification strategy. We introduce a high-throughput dose-response cellular thermal shift assay (HTDR-CETSA), a single-pot homogenous assay adapted for high-density microtiter plate format. The assay features titratable BacMam expression of full-length target proteins fused to the DiscoverX 42 amino acid ePL tag in HeLa suspension cells, facilitating enzyme fragment complementation-based chemiluminescent quantification of ligand-stabilized soluble protein. This simplified format can accommodate determination of full-dose CETSA curves for hundreds of individual compounds/analyst/day in replicates. HTDR-CETSA data generated for substrate site and alternate binding mode inhibitors of the histone-lysine N-methyltransferase SMYD3 in HeLa suspension cells demonstrate excellent correlation with rank-order potencies observed in cellular mechanistic assays and direct translation to target engagement of endogenous Smyd3 in cancer-relevant cell lines. We envision this workflow to be generically applicable to HTDR-CETSA screening spanning a wide variety of soluble intracellular protein target classes.


Assuntos
Descoberta de Drogas/métodos , Inibidores Enzimáticos/farmacologia , Ensaios de Triagem em Larga Escala , Histona-Lisina N-Metiltransferase/antagonistas & inibidores , Indolamina-Pirrol 2,3,-Dioxigenase/antagonistas & inibidores , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Ativação Enzimática , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Indolamina-Pirrol 2,3,-Dioxigenase/genética , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Bibliotecas de Moléculas Pequenas , Fluxo de Trabalho
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