Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 217
Filtrar
1.
Mol Cell ; 81(16): 3368-3385.e9, 2021 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-34375583

RESUMO

The mechanistic understanding of nascent RNAs in transcriptional control remains limited. Here, by a high sensitivity method methylation-inscribed nascent transcripts sequencing (MINT-seq), we characterized the landscapes of N6-methyladenosine (m6A) on nascent RNAs. We uncover heavy but selective m6A deposition on nascent RNAs produced by transcription regulatory elements, including promoter upstream antisense RNAs and enhancer RNAs (eRNAs), which positively correlates with their length, inclusion of m6A motif, and RNA abundances. m6A-eRNAs mark highly active enhancers, where they recruit nuclear m6A reader YTHDC1 to phase separate into liquid-like condensates, in a manner dependent on its C terminus intrinsically disordered region and arginine residues. The m6A-eRNA/YTHDC1 condensate co-mixes with and facilitates the formation of BRD4 coactivator condensate. Consequently, YTHDC1 depletion diminished BRD4 condensate and its recruitment to enhancers, resulting in inhibited enhancer and gene activation. We propose that chemical modifications of eRNAs together with reader proteins play broad roles in enhancer activation and gene transcriptional control.


Assuntos
Adenosina/análogos & derivados , Proteínas de Ciclo Celular/genética , Proteínas do Tecido Nervoso/genética , Fatores de Processamento de RNA/genética , RNA/genética , Fatores de Transcrição/genética , Adenosina/genética , Elementos Facilitadores Genéticos/genética , Regulação da Expressão Gênica/genética , Humanos , Metilação , Elementos Reguladores de Transcrição/genética , Ativação Transcricional/genética
2.
Immunity ; 50(3): 576-590.e6, 2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30770249

RESUMO

Elevated glucose metabolism in immune cells represents a hallmark feature of many inflammatory diseases, such as sepsis. However, the role of individual glucose metabolic pathways during immune cell activation and inflammation remains incompletely understood. Here, we demonstrate a previously unrecognized anti-inflammatory function of the O-linked ß-N-acetylglucosamine (O-GlcNAc) signaling associated with the hexosamine biosynthesis pathway (HBP). Despite elevated activities of glycolysis and the pentose phosphate pathway, activation of macrophages with lipopolysaccharide (LPS) resulted in attenuated HBP activity and protein O-GlcNAcylation. Deletion of O-GlcNAc transferase (OGT), a key enzyme for protein O-GlcNAcylation, led to enhanced innate immune activation and exacerbated septic inflammation. Mechanistically, OGT-mediated O-GlcNAcylation of the serine-threonine kinase RIPK3 on threonine 467 (T467) prevented RIPK3-RIPK1 hetero- and RIPK3-RIPK3 homo-interaction and inhibited downstream innate immunity and necroptosis signaling. Thus, our study identifies an immuno-metabolic crosstalk essential for fine-tuning innate immune cell activation and highlights the importance of glucose metabolism in septic inflammation.


Assuntos
Apoptose/fisiologia , Inflamação/metabolismo , N-Acetilglucosaminiltransferases/metabolismo , Necrose/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Animais , Linhagem Celular , Glucose/metabolismo , Humanos , Imunidade Inata/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Serina/metabolismo , Transdução de Sinais/fisiologia , Treonina/metabolismo
3.
Proc Natl Acad Sci U S A ; 121(14): e2315509121, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38547055

RESUMO

Dysregulation of polyamine metabolism has been implicated in cancer initiation and progression; however, the mechanism of polyamine dysregulation in cancer is not fully understood. In this study, we investigated the role of MUC1, a mucin protein overexpressed in pancreatic cancer, in regulating polyamine metabolism. Utilizing pancreatic cancer patient data, we noted a positive correlation between MUC1 expression and the expression of key polyamine metabolism pathway genes. Functional studies revealed that knockdown of spermidine/spermine N1-acetyltransferase 1 (SAT1), a key enzyme involved in polyamine catabolism, attenuated the oncogenic functions of MUC1, including cell survival and proliferation. We further identified a regulatory axis whereby MUC1 stabilized hypoxia-inducible factor (HIF-1α), leading to increased SAT1 expression, which in turn induced carbon flux into the tricarboxylic acid cycle. MUC1-mediated stabilization of HIF-1α enhanced the promoter occupancy of the latter on SAT1 promoter and corresponding transcriptional activation of SAT1, which could be abrogated by pharmacological inhibition of HIF-1α or CRISPR/Cas9-mediated knockout of HIF1A. MUC1 knockdown caused a significant reduction in the levels of SAT1-generated metabolites, N1-acetylspermidine and N8-acetylspermidine. Given the known role of MUC1 in therapy resistance, we also investigated whether inhibiting SAT1 would enhance the efficacy of FOLFIRINOX chemotherapy. By utilizing organoid and orthotopic pancreatic cancer mouse models, we observed that targeting SAT1 with pentamidine improved the efficacy of FOLFIRINOX, suggesting that the combination may represent a promising therapeutic strategy against pancreatic cancer. This study provides insights into the interplay between MUC1 and polyamine metabolism, offering potential avenues for the development of treatments against pancreatic cancer.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias Pancreáticas , Camundongos , Animais , Humanos , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Poliaminas/metabolismo , Transdução de Sinais , Acetiltransferases/genética , Acetiltransferases/metabolismo , Mucina-1
4.
Nat Chem Biol ; 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39030363

RESUMO

Lysine L-lactylation (Kl-la) is a novel protein posttranslational modification (PTM) driven by L-lactate. This PTM has three isomers: Kl-la, N-ε-(carboxyethyl)-lysine (Kce) and D-lactyl-lysine (Kd-la), which are often confused in the context of the Warburg effect and nuclear presence. Here we introduce two methods to differentiate these isomers: a chemical derivatization and high-performance liquid chromatography analysis for efficient separation, and isomer-specific antibodies for high-selectivity identification. We demonstrated that Kl-la is the primary lactylation isomer on histones and dynamically regulated by glycolysis, not Kd-la or Kce, which are observed when the glyoxalase system was incomplete. The study also reveals that lactyl-coenzyme A, a precursor in L-lactylation, correlates positively with Kl-la levels. This work not only provides a methodology for distinguishing other PTM isomers, but also highlights Kl-la as the primary responder to glycolysis and the Warburg effect.

5.
Trends Immunol ; 43(1): 78-92, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34942082

RESUMO

Cholesterol is a multifaceted metabolite that is known to modulate processes in cancer, atherosclerosis, and autoimmunity. A common denominator between these diseases appears to be the immune system, in which many cholesterol-associated metabolites impact both adaptive and innate immunity. Many cancers display altered cholesterol metabolism, and recent studies demonstrate that manipulating systemic cholesterol metabolism may be useful in improving immunotherapy responses. However, cholesterol can have both proinflammatory and anti-inflammatory roles in mammals, acting via multiple immune cell types, and depending on context. Gaining mechanistic insights into various cholesterol-related metabolites can improve our understanding of their functions and extensive effects on the immune system, and ideally will inform the design of future therapeutic strategies against cancer and/or other pathologies.


Assuntos
Aterosclerose , Neoplasias , Animais , Anti-Inflamatórios , Colesterol/metabolismo , Humanos , Imunidade Inata , Mamíferos , Neoplasias/tratamento farmacológico
6.
PLoS Biol ; 20(5): e3001634, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35584084

RESUMO

Therapeutic methods to modulate skin pigmentation has important implications for skin cancer prevention and for treating cutaneous hyperpigmentary conditions. Towards defining new potential targets, we followed temporal dynamics of melanogenesis using a cell-autonomous pigmentation model. Our study elucidates 3 dominant phases of synchronized metabolic and transcriptional reprogramming. The melanogenic trigger is associated with high MITF levels along with rapid uptake of glucose. The transition to pigmented state is accompanied by increased glucose channelisation to anabolic pathways that support melanosome biogenesis. SREBF1-mediated up-regulation of fatty acid synthesis results in a transient accumulation of lipid droplets and enhancement of fatty acids oxidation through mitochondrial respiration. While this heightened bioenergetic activity is important to sustain melanogenesis, it impairs mitochondria lately, shifting the metabolism towards glycolysis. This recovery phase is accompanied by activation of the NRF2 detoxication pathway. Finally, we show that inhibitors of lipid metabolism can resolve hyperpigmentary conditions in a guinea pig UV-tanning model. Our study reveals rewiring of the metabolic circuit during melanogenesis, and fatty acid metabolism as a potential therapeutic target in a variety of cutaneous diseases manifesting hyperpigmentary phenotype.


Assuntos
Metabolismo dos Lipídeos , Melaninas , Pigmentação da Pele , Animais , Ácidos Graxos , Glucose , Cobaias , Melaninas/metabolismo
7.
J Biol Chem ; 299(7): 104865, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37268160

RESUMO

Spleen tyrosine kinase (Syk) is expressed in a variety of hemopoietic cells. Upon phosphorylation of the platelet immunoreceptor-based activation motif of the glycoprotein VI (GPVI)/Fc receptor gamma chain collagen receptor, both the tyrosine phosphorylation and activity of Syk are increased leading to downstream signaling events. Although it has been established that the activity of Syk is regulated by tyrosine phosphorylation, the specific roles of individual phosphorylation sites remain to be elucidated. We observed that Syk Y346 in mouse platelets was still phosphorylated when GPVI-induced Syk activity was inhibited. We then generated Syk Y346F mice and analyzed the effect this mutation exerts on platelet responses. Syk Y346F mice bred normally, and their blood cell count was unaltered. We did observe potentiation of GPVI-induced platelet aggregation and ATP secretion as well as increased phosphorylation of other tyrosines on Syk in the Syk Y346F mouse platelets when compared to WT littermates. This phenotype was specific for GPVI-dependent activation, since it was not seen when AYPGKF, a PAR4 agonist, or 2-MeSADP, a purinergic receptor agonist, was used to activate platelets. Despite a clear effect of Syk Y346F on GPVI-mediated signaling and cellular responses, there was no effect of this mutation on hemostasis as measured by tail-bleeding times, although the time to thrombus formation determined using the ferric chloride injury model was reduced. Thus, our results indicate a significant effect of Syk Y346F on platelet activation and responses in vitro and reveal its complex nature manifesting itself by the diversified translation of platelet activation into physiological responses.


Assuntos
Plaquetas , Agregação Plaquetária , Quinase Syk , Animais , Camundongos , Fosforilação , Ativação Plaquetária , Glicoproteínas da Membrana de Plaquetas/genética , Glicoproteínas da Membrana de Plaquetas/metabolismo , Quinase Syk/genética , Quinase Syk/metabolismo , Tirosina
8.
Mol Cell ; 63(4): 608-620, 2016 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-27499294

RESUMO

The UbiB protein kinase-like (PKL) family is widespread, comprising one-quarter of microbial PKLs and five human homologs, yet its biochemical activities remain obscure. COQ8A (ADCK3) is a mammalian UbiB protein associated with ubiquinone (CoQ) biosynthesis and an ataxia (ARCA2) through unclear means. We show that mice lacking COQ8A develop a slowly progressive cerebellar ataxia linked to Purkinje cell dysfunction and mild exercise intolerance, recapitulating ARCA2. Interspecies biochemical analyses show that COQ8A and yeast Coq8p specifically stabilize a CoQ biosynthesis complex through unorthodox PKL functions. Although COQ8 was predicted to be a protein kinase, we demonstrate that it lacks canonical protein kinase activity in trans. Instead, COQ8 has ATPase activity and interacts with lipid CoQ intermediates, functions that are likely conserved across all domains of life. Collectively, our results lend insight into the molecular activities of the ancient UbiB family and elucidate the biochemical underpinnings of a human disease.


Assuntos
Comportamento Animal , Ataxia Cerebelar/enzimologia , Cerebelo/enzimologia , Proteínas Mitocondriais/deficiência , Músculo Esquelético/enzimologia , Ubiquinona/deficiência , Animais , Células COS , Ataxia Cerebelar/genética , Ataxia Cerebelar/fisiopatologia , Ataxia Cerebelar/psicologia , Cerebelo/fisiopatologia , Cerebelo/ultraestrutura , Chlorocebus aethiops , Modelos Animais de Doenças , Tolerância ao Exercício , Feminino , Predisposição Genética para Doença , Células HEK293 , Humanos , Metabolismo dos Lipídeos , Masculino , Aprendizagem em Labirinto , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Mitocondriais/química , Proteínas Mitocondriais/genética , Modelos Moleculares , Atividade Motora , Força Muscular , Músculo Esquelético/fisiopatologia , Fenótipo , Ligação Proteica , Conformação Proteica , Proteômica/métodos , Reconhecimento Psicológico , Teste de Desempenho do Rota-Rod , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Convulsões/enzimologia , Convulsões/genética , Convulsões/fisiopatologia , Relação Estrutura-Atividade , Fatores de Tempo , Transfecção , Ubiquinona/química , Ubiquinona/genética
9.
Nucleic Acids Res ; 50(6): 3394-3412, 2022 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-35286386

RESUMO

Pancreatic ductal adenocarcinoma (PDAC), one of the most aggressive types of cancer, is characterized by aberrant activity of oncogenic KRAS. A nuclease-hypersensitive GC-rich region in KRAS promoter can fold into a four-stranded DNA secondary structure called G-quadruplex (G4), known to regulate KRAS expression. However, the factors that regulate stable G4 formation in the genome and KRAS expression in PDAC are largely unknown. Here, we show that APE1 (apurinic/apyrimidinic endonuclease 1), a multifunctional DNA repair enzyme, is a G4-binding protein, and loss of APE1 abrogates the formation of stable G4 structures in cells. Recombinant APE1 binds to KRAS promoter G4 structure with high affinity and promotes G4 folding in vitro. Knockdown of APE1 reduces MAZ transcription factor loading onto the KRAS promoter, thus reducing KRAS expression in PDAC cells. Moreover, downregulation of APE1 sensitizes PDAC cells to chemotherapeutic drugs in vitro and in vivo. We also demonstrate that PDAC patients' tissue samples have elevated levels of both APE1 and G4 DNA. Our findings unravel a critical role of APE1 in regulating stable G4 formation and KRAS expression in PDAC and highlight G4 structures as genomic features with potential application as a novel prognostic marker and therapeutic target in PDAC.


Assuntos
Carcinoma Ductal Pancreático , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/metabolismo , Quadruplex G , Neoplasias Pancreáticas , Proteínas Proto-Oncogênicas p21(ras) , Carcinoma Ductal Pancreático/genética , DNA/química , Endonucleases/metabolismo , Humanos , Neoplasias Pancreáticas/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Neoplasias Pancreáticas
11.
Gastroenterology ; 161(5): 1584-1600, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34245764

RESUMO

BACKGROUND & AIMS: SIRT5 plays pleiotropic roles via post-translational modifications, serving as a tumor suppressor, or an oncogene, in different tumors. However, the role SIRT5 plays in the initiation and progression of pancreatic ductal adenocarcinoma (PDAC) remains unknown. METHODS: Published datasets and tissue arrays with SIRT5 staining were used to investigate the clinical relevance of SIRT5 in PDAC. Furthermore, to define the role of SIRT5 in the carcinogenesis of PDAC, we generated autochthonous mouse models with conditional Sirt5 knockout. Moreover, to examine the mechanistic role of SIRT5 in PDAC carcinogenesis, SIRT5 was knocked down in PDAC cell lines and organoids, followed by metabolomics and proteomics studies. A novel SIRT5 activator was used for therapeutic studies in organoids and patient-derived xenografts. RESULTS: SIRT5 expression negatively regulated tumor cell proliferation and correlated with a favorable prognosis in patients with PDAC. Genetic ablation of Sirt5 in PDAC mouse models promoted acinar-to-ductal metaplasia, precursor lesions, and pancreatic tumorigenesis, resulting in poor survival. Mechanistically, SIRT5 loss enhanced glutamine and glutathione metabolism via acetylation-mediated activation of GOT1. A selective SIRT5 activator, MC3138, phenocopied the effects of SIRT5 overexpression and exhibited antitumor effects on human PDAC cells. MC3138 also diminished nucleotide pools, sensitizing human PDAC cell lines, organoids, and patient-derived xenografts to gemcitabine. CONCLUSIONS: Collectively, we identify SIRT5 as a key tumor suppressor in PDAC, whose loss promotes tumorigenesis through increased noncanonic use of glutamine via GOT1, and that SIRT5 activation is a novel therapeutic strategy to target PDAC.


Assuntos
Carcinoma Ductal Pancreático/enzimologia , Metabolismo Energético , Neoplasias Pancreáticas/enzimologia , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Sirtuínas/deficiência , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Aspartato Aminotransferase Citoplasmática/genética , Aspartato Aminotransferase Citoplasmática/metabolismo , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Progressão da Doença , Metabolismo Energético/efeitos dos fármacos , Ativação Enzimática , Ativadores de Enzimas/farmacologia , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Mutação , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Transdução de Sinais , Sirtuínas/genética , Carga Tumoral , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto , Gencitabina
12.
PLoS Pathog ; 16(3): e1008354, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32142554

RESUMO

Biofilm-associated prosthetic joint infections (PJIs) cause significant morbidity due to their recalcitrance to immune-mediated clearance and antibiotics, with Staphylococcus aureus (S. aureus) among the most prevalent pathogens. We previously demonstrated that S. aureus biofilm-associated monocytes are polarized to an anti-inflammatory phenotype and the adoptive transfer of pro-inflammatory macrophages attenuated biofilm burden, highlighting the critical role of monocyte/macrophage inflammatory status in dictating biofilm persistence. The inflammatory properties of leukocytes are linked to their metabolic state, and here we demonstrate that biofilm-associated monocytes exhibit a metabolic bias favoring oxidative phosphorylation (OxPhos) and less aerobic glycolysis to facilitate their anti-inflammatory activity and biofilm persistence. To shift monocyte metabolism in vivo and reprogram cells to a pro-inflammatory state, a nanoparticle approach was utilized to deliver the OxPhos inhibitor oligomycin to monocytes. Using a mouse model of S. aureus PJI, oligomycin nanoparticles were preferentially internalized by monocytes, which significantly reduced S. aureus biofilm burden by altering metabolism and promoting the pro-inflammatory properties of infiltrating monocytes as revealed by metabolomics and RT-qPCR, respectively. Injection of oligomycin alone had no effect on monocyte metabolism or biofilm burden, establishing that intracellular delivery of oligomycin is required to reprogram monocyte metabolic activity and that oligomycin lacks antibacterial activity against S. aureus biofilms. Remarkably, monocyte metabolic reprogramming with oligomycin nanoparticles was effective at clearing established biofilms in combination with systemic antibiotics. These findings suggest that metabolic reprogramming of biofilm-associated monocytes may represent a novel therapeutic approach for PJI.


Assuntos
Biofilmes/efeitos dos fármacos , Reprogramação Celular/efeitos dos fármacos , Implantes Experimentais/microbiologia , Monócitos/metabolismo , Oligomicinas/farmacologia , Infecções Estafilocócicas/metabolismo , Staphylococcus aureus/fisiologia , Animais , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/patologia , Camundongos , Monócitos/patologia , Fosforilação Oxidativa/efeitos dos fármacos , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/patologia
13.
Crit Rev Food Sci Nutr ; 62(5): 1204-1221, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33103462

RESUMO

Amorphous solid products have recently gained a lot of attention as key solutions to improve the solubility and bioavailability of poorly soluble nutraceuticals. A pure amorphous drug is a high-energy form; physically/chemically unstable and so easily gets recrystallized into the less soluble crystalline form limiting solubility and bioavailability issues. Amorphous solid dispersion and co-amorphous are new formulation approach that stabilized unstable amorphous form through different mechanisms such as preventing mobility, high glass transition temperature and molecular interaction. Nutraceuticals have been received the utmost importance due to their health benefits. However, most of these compounds have been associated with poor oral bioavailability due to poor solubility, high lipophilicity, high melting point, poor permeability, degradability and rapid metabolism in the gastrointestinal tract (GIT) which limits its health benefits. This review provides us a systematic application of amorphous systems to the delivery of poorly soluble nutraceuticals, with the aim of overcoming their pharmacokinetic limitations and improved pharmacological potential. In particular, it describes the challenges associated with delivery of oral nutraceuticals, various methods involved in the preparation and characterization of amorphous systems and permeability enhancement of nutraceuticals are in detail.


Assuntos
Preparações Farmacêuticas , Disponibilidade Biológica , Suplementos Nutricionais , Estabilidade de Medicamentos , Solubilidade
14.
J Liposome Res ; 32(4): 386-395, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35225132

RESUMO

The present investigation was envisaged to develop liposomal formulation for efficacious and targeted delivery of epidermal growth factor receptor (EGFR) inhibitor (erlotinib) against pancreatic cancer. The marketed formulations bearing current EGFR inhibitors exhibit serious adverse effects including severe skin, hemolytic and gastrointestinal toxicity. To address the obstacles, we have developed the liposomal formulation, by ether injection method, comprising erlotinib, a tyrosine kinase EGFR inhibitor, proposed to be targeted through enhanced permeability and retention effect (EPR) effect against pancreatic cancer. On succeeding, the liposomes were characterized for various pharmaceutical attributes. The developed liposomes found to sustain a particle size of 121 ± 10.7 nm, whereas PDI of 0.22 ± 0.01 with the surface charge value of -33.7 ± 2.30 mV. The entrapment efficiency and drug loading were found to be 82.60 and 15.89 (%w/w), respectively. The hemolysis study suggested that the developed formulation was safer compared with native drug solution. The proof of concept for enhanced efficacy and decreased toxicity has been established through in vitro assays. The IC50 for free erlotinib and formulation was found to be 2.0 ± 0.3 µg/ml and 1.1 ± 0.1 µg/ml, respectively. The effectivity was evident by cellular uptake study and apoptosis, whereas cell cycle arrest study indicated that erlotinib arrests the G0/G1 phase of cell cycle. Further the erlotinib-asolectin liposomal formulation enhanced cytotoxicity in PANC-1 cells at relatively low dose, proving to be an alternative for current chemotherapeutics against pancreatic cancer.


Assuntos
Lipossomos , Neoplasias Pancreáticas , Humanos , Cloridrato de Erlotinib/farmacologia , Linhagem Celular Tumoral , Receptores ErbB/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Neoplasias Pancreáticas
15.
Arch Pharm (Weinheim) ; 355(9): e2200108, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35618489

RESUMO

Aldehyde dehydrogenase 1 (ALDH1A1), an oxidoreductase class of enzymes, is overexpressed in various types of cancer cell lines and is the major cause of resistance to the Food and Drug Administration (FDA)-approved drug, cyclophosphamide (CP). In cancer conditions, CP undergoes a sequence of biotransformations to form an active metabolite, aldophosphamide, which further biotransforms to its putative cytotoxic metabolite, phosphoramide mustard. However, in resistant cancer conditions, aldophosphamide is converted into its inactive metabolite, carboxyphosphamide, via oxidation with ALDH1A1. Herein, to address the issue of ALDH1A1 mediated CP resistance, we report a series of benzo[d]oxazol-2(3H)-one and 2-oxazolo[4,5-b]pyridin-2(3H)-one derivatives as selective ALDH1A1 inhibitors. These inhibitors were designed using a validated 3D-quantitative structure activity relationship (3D-QSAR) model coupled with scaffold hopping. The 3D-QSAR model was developed using reported indole-2,3-diones based ALDH1A1 inhibitors, which provided field points in terms of electrostatic, van der Waals and hydrophobic potentials required for selectively inhibiting ALDH1A1. The most selective indole-2,3-diones-based compound, that is, cmp 3, was further considered for scaffold hopping. Two top-ranked bioisosteres, that is, benzo[d]oxazol-2(3H)-one and 2-oxazolo[4,5-b]pyridin-2(3H)-one, were selected for designing new inhibitors by considering the field pattern of 3D-QSAR. All designed molecules were mapped perfectly on the 3D-QSAR model and found to be predictive with good inhibitory potency (pIC50 range: 7.5-6.8). Molecular docking was carried out for each designed molecule to identify key interactions that are required for ALDH1A1 inhibition and to authenticate the 3D-QSAR result. The top five inhibitor-ALDH1A1 complexes were also submitted for molecular dynamics simulations to access their stability. In vitro enzyme assays of 21 compounds suggested that these compounds are selective toward ALDH1A1 over the other two isoforms, that is, ALDH2 and ALDH3A1. All the compounds were found to be at least three and two times more selective toward ALDH1A1 over ALDH2 and ALDH3A1, respectively. All the compounds showed an IC50 value in the range of 0.02-0.80 µM, which indicates the potential for these to be developed as adjuvant therapy for CP resistance.


Assuntos
Danazol , Relação Quantitativa Estrutura-Atividade , Aldeído Desidrogenase/metabolismo , Família Aldeído Desidrogenase 1 , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Indóis , Simulação de Acoplamento Molecular , Retinal Desidrogenase/metabolismo
16.
J Cell Physiol ; 236(8): 5715-5724, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33400284

RESUMO

Periodontal ligament fibroblasts (PdLFs) are an elongated cell type in the periodontium with matrix and bone regulatory functions which become abnormal in periodontal disease (PD). Here we found that the normally elongated and oriented PdLF nucleus becomes rounded and loses orientation in a mouse model of PD. Using in vitro micropatterning of cultured primary PdLF cell shape, we show that PdLF elongation correlates with nuclear elongation and the presence of thicker, contractile F-actin fibers. The rounded nuclei in mouse PD models in vivo are, therefore, indicative of reduced actomyosin tension. Inhibiting actomyosin contractility by inhibiting myosin light chain kinase, Rho kinase or myosin ATPase activity, in cultured PdLFs each consistently reduced messenger RNA levels of bone regulatory protein osteoprotegerin (OPG). Infection of cultured PdLFs with two different types of periodontal bacteria (Porphyromonas gingivalis and Fusobacterium nucleatum) failed to recapitulate the observed nuclear rounding in vivo, upregulated nonmuscle myosin II phosphorylation and downregulated OPG. Collectively, our results add support to the hypothesis that PdLF contractility becomes decreased and contributes to disease progression in PD.


Assuntos
Actomiosina/metabolismo , Fibroblastos/metabolismo , Osteoprotegerina/metabolismo , Ligamento Periodontal/efeitos dos fármacos , Animais , Citocinas/metabolismo , Interleucina-1beta/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Ligamento Periodontal/metabolismo , Porphyromonas gingivalis/metabolismo
17.
Gastroenterology ; 159(5): 1866-1881.e8, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32717220

RESUMO

BACKGROUND & AIMS: Development of pancreatic ductal adenocarcinoma (PDA) involves acinar to ductal metaplasia and genesis of tuft cells. It has been a challenge to study these rare cells because of the lack of animal models. We investigated the role of tuft cells in pancreatic tumorigenesis. METHODS: We performed studies with LSL-KrasG12D/+;Ptf1aCre/+ mice (KC; develop pancreatic tumors), KC mice crossed with mice with pancreatic disruption of Pou2f3 (KPouC mice; do not develop tuft cells), or mice with pancreatic disruption of the hematopoietic prostaglandin D synthase gene (Hpgds, KHC mice) and wild-type mice. Mice were allowed to age or were given caerulein to induce pancreatitis; pancreata were collected and analyzed by histology, immunohistochemistry, RNA sequencing, ultrastructural microscopy, and metabolic profiling. We performed laser-capture dissection and RNA-sequencing analysis of pancreatic tissues from 26 patients with pancreatic intraepithelial neoplasia (PanIN), 19 patients with intraductal papillary mucinous neoplasms (IPMNs), and 197 patients with PDA. RESULTS: Pancreata from KC mice had increased formation of tuft cells and higher levels of prostaglandin D2 than wild-type mice. Pancreas-specific deletion of POU2F3 in KC mice (KPouC mice) resulted in a loss of tuft cells and accelerated tumorigenesis. KPouC mice had increased fibrosis and activation of immune cells after administration of caerulein. Pancreata from KPouC and KHC mice had significantly lower levels of prostaglandin D2, compared with KC mice, and significantly increased numbers of PanINs and PDAs. KPouC and KHC mice had increased pancreatic injury after administration of caerulein, significantly less normal tissue, more extracellular matrix deposition, and higher PanIN grade than KC mice. Human PanIN and intraductal papillary mucinous neoplasm had gene expression signatures associated with tuft cells and increased expression of Hpgds messenger RNA compared with PDA. CONCLUSIONS: In mice with KRAS-induced pancreatic tumorigenesis, loss of tuft cells accelerates tumorigenesis and increases the severity of caerulein-induced pancreatic injury, via decreased production of prostaglandin D2. These data are consistent with the hypothesis that tuft cells are a metaplasia-induced tumor attenuating cell type.


Assuntos
Carcinoma Ductal Pancreático/prevenção & controle , Transformação Celular Neoplásica/metabolismo , Pâncreas/metabolismo , Neoplasias Pancreáticas/prevenção & controle , Prostaglandina D2/metabolismo , Animais , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Ceruletídeo , Modelos Animais de Doenças , Metabolismo Energético , Fibrose , Humanos , Interleucinas/genética , Interleucinas/metabolismo , Oxirredutases Intramoleculares/genética , Oxirredutases Intramoleculares/metabolismo , Camundongos Transgênicos , Mutação , Fatores de Transcrição de Octâmero/genética , Fatores de Transcrição de Octâmero/metabolismo , Pâncreas/patologia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Pancreatite/induzido quimicamente , Pancreatite/genética , Pancreatite/metabolismo , Pancreatite/patologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Fatores de Tempo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Bioorg Chem ; 107: 104595, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33450548

RESUMO

Due to hurdles, including resistance, adverse effects, and poor bioavailability, among others linked with existing therapies, there is an urgent unmet need to devise new, safe, and more effective treatment modalities for skin cancers. Herein, a series of flavonol-based derivatives of fisetin, a plant-based flavonoid identified as an anti-tumorigenic agent targeting the mammalian targets of rapamycin (mTOR)-regulated pathways, were synthesized and fully characterized. New potential inhibitors of receptor tyrosine kinases (c-KITs), cyclin-dependent kinase-2 (CDK2), and mTOR, representing attractive therapeutic targets for melanoma and non-melanoma skin cancers (NMSCs) treatment, were identified using inverse-docking, in vitro kinase activity and various cell-based anticancer screening assays. Eleven compounds exhibited significant inhibitory activities greater than the parent molecule against four human skin cancer cell lines, including melanoma (A375 and SK-Mel-28) and NMSCs (A431 and UWBCC1), with IC50 values ranging from 0.12 to < 15 µM. Seven compounds were identified as potentially potent single, dual or multi-kinase c-KITs, CDK2, and mTOR kinase inhibitors after inverse-docking and screening against twelve known cancer targets, followed by kinase activity profiling. Moreover, the potent compound F20, and the multi-kinase F9 and F17 targeted compounds, markedly decreased scratch wound closure, colony formation, and heightened expression levels of key cancer-promoting pathway molecular targets c-Kit, CDK2, and mTOR. In addition, these compounds downregulated Bcl-2 levels and upregulated Bax and cleaved caspase-3/7/8 and PARP levels, thus inducing apoptosis of A375 and A431 cells in a dose-dependent manner. Overall, compounds F20, F9 and F17, were identified as promising c-Kit, CDK2 and mTOR inhibitors, worthy of further investigation as therapeutics, or as adjuvants to standard therapies for the control of melanoma and NMSCs.


Assuntos
Antineoplásicos/farmacologia , Flavonóis/farmacologia , Melanoma/tratamento farmacológico , Simulação de Acoplamento Molecular , Neoplasias Cutâneas/tratamento farmacológico , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Quinase 2 Dependente de Ciclina/antagonistas & inibidores , Quinase 2 Dependente de Ciclina/metabolismo , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Flavonóis/síntese química , Flavonóis/química , Humanos , Melanoma/metabolismo , Melanoma/patologia , Estrutura Molecular , Proteínas Proto-Oncogênicas c-kit/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-kit/metabolismo , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Relação Estrutura-Atividade , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismo , Células Tumorais Cultivadas
19.
Indian J Crit Care Med ; 25(11): 1308-1313, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34866831

RESUMO

BACKGROUND: Healthcare-associated infections (HAIs) can impact the outcome following traumatic brain injury (TBI) in children. We undertook a retrospective observational study to see the incidence, risk factors, and microbiological profile for HAIs in pediatric TBI. We also studied the impact of baseline patient characteristics, HAIs on patient outcome, and antibiotic resistance of different types of bacteria. MATERIALS AND METHODS: Data on pediatric TBI patients of age up to 12 years were collected via a computerized patient record system (CPRS) from January 2012 to December 2018. Descriptive Chi-square test and Wilcoxon signed rank test were used to characterize baseline parameters. General linear regression models were run to find an unadjusted and adjusted odds ratio (OR). RESULTS: HAIs were found in 144 (34%) out of 423 patients. The most commonly seen infections were of the respiratory tract in 73 (17.26%) subjects. The most predominant microorganism isolated was Acinetobacter baumannii in 188 (41%) samples. A. baumannii was sensitive to colistin in 91 (48.4%) patients. Male gender (OR 0.630; p-value 0.035), fall from height (OR 0.374; p-value 0.008), and higher injury severity scale (ISS) (OR 1.040; p-value 0.002) were independent risk factors for development of HAIs. Severe TBI, higher ISS and Marshall grade, and HAIs were significantly associated with poor patient outcome. CONCLUSION: Severe TBI poses a significant risk of HAIs. The most common site was the respiratory tract, predominately infected with A. baumannii. HAIs in pediatric TBI patients resulted in poor patient outcome. HOW TO CITE THIS ARTICLE: Prasad C, Bindra A, Singh P, Singh GP, Singh PK, Mathur P. Healthcare-associated Infections in Pediatric Patients in Neurotrauma Intensive Care Unit: A Retrospective Analysis. Indian J Crit Care Med 2021;25(11):1308-1313.

20.
J Contemp Dent Pract ; 21(12): 1354-1360, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33893258

RESUMO

AIM AND OBJECTIVE: The growth of the temporomandibular joint (TMJ) gets affected by multiple factors like aging, occlusion state, and by the movement of the jaw while masticating and swallowing. Radiographic imaging is often utilized as a vital diagnostic adjunct in the evaluation of certain examinations of the TMJ. MATERIALS AND METHODS: In this in vivo study, 30 male participants with mean age 55 years, having edentulous maxillary and mandibular arches from the Outpatient Department of Prosthodontics, were randomly selected. Group I (n = 30) patients who were edentulous for the last 4-5 years but without wearing dentures. Whereas group II (n = 30) patients who were edentulous for the last 4-5 years but were wearing dentures for this period. Maxillary and mandibular dentures were fabricated and delivered to subjects. Subjects were subjected to the TMJ analysis with the help of CBCT. Radiological images of dentomaxillofacial structures were analyzed by a specialist with a dual monitor inside a darkened silent room. On the monitor, three times measurements were recorded followed by calculation of mean value. The recordings were taken on both sides and thus, 210 sites were analyzed altogether, followed by the statistical analysis using SPSS software version 15.0. RESULTS: The mean ages of group I and II were 59.00 ± 6.74 and 58.27 ± 6.75 years, respectively. The intra- and intergroup comparisons were done using a one-sample t-test. Differences in mean intercondylar width in groups I and II were not found to be statistically significant. The difference in mean length of glenoid fossa was not statistically significant at any of the above observation periods. A continuous decline in mean length of glenoid fossa was observed with time in both groups. The range of change in articular eminence length was found to be statistically significant for both the groups (p < 0.05). CONCLUSION: This study shows that the articular eminence flattening is correlated with age; on the other hand, the rate of deformation was found significantly more in total edentulous subjects as compared to subjects having normally maintained occlusion. The anatomical changes inside the TMJ have been much greater expressed within the completely edentulous subjects in whom the angle of sagittal condyle path declines and so does the articular eminence height. CLINICAL SIGNIFICANCE: It is essential to provide the edentulous patient with early prosthetic and occlusal rehabilitation after extractions to prevent the anatomical changes in TMJ.


Assuntos
Cavidade Glenoide , Côndilo Mandibular , Idoso , Tomografia Computadorizada de Feixe Cônico , Dentaduras , Humanos , Masculino , Pessoa de Meia-Idade , Articulação Temporomandibular/diagnóstico por imagem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA