RESUMO
The tumor suppressor p53 plays important roles in suppressing the development and progression of cancer by responding to various stress signals. In addition, p53 can regulate the metabolic pathways of cancer cells by regulating energy metabolism and oxidative phosphorylation. Here, we present a mechanism for the interaction between p53 and ZNF568. Initially, we used X-ray crystallography to determine the irregular loop structure of the ZNF568 KRAB domain; this loop plays an important role in the interaction between p53 and ZNF568. In addition, Cryo-EM was used to examine how the p53 DBD and ZNF568 KRAB domains bind together. The function of ZNF568 on p53-mediated mitochondrial respiration was confirmed by measuring glucose consumption and lactate production. These findings show that ZNF568 can reduce p53-mediated mitochondrial respiratory activity by binding to p53 and inhibiting the transcription of SCO2. SIGNIFICANCE: ZNF568 can directly bind to the p53 DBD and transcriptionally regulate the SCO2 gene. SCO2 transcriptional regulation by interaction between ZNF568 and p53 may regulate the balance between mitochondrial respiration and glycolysis.
Assuntos
Mitocôndrias , Fosforilação Oxidativa , Ligação Proteica , Proteína Supressora de Tumor p53 , Humanos , Proteínas de Transporte/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/química , Cristalografia por Raios X , Glicólise , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/química , Modelos Moleculares , Chaperonas Moleculares/metabolismo , Chaperonas Moleculares/genética , Proteína Supressora de Tumor p53/metabolismo , Proteína Supressora de Tumor p53/genéticaRESUMO
The folate metabolism enzyme ALDH1L1 catalyzed 10-formyltetrahydrofolate to tetrahydrofolate and CO2. Non-small cell lung cancer cells (NSCLC) strongly express ALDH1L1. Gossypol binds to an allosteric site and disrupts the folate metabolism by preventing NADP+ binding. The Cryo-EM structures of tetrameric C-terminal aldehyde dehydrogenase human ALDH1L1 complex with gossypol were examined. Gossypol-bound ALDH1L1 interfered with NADP+ by shifting the allosteric site of the structural conformation, producing a closed-form NADP+ binding site. In addition, the inhibition activity of ALDH1L1 was targeted with gossypol in NSCLC. The gossypol treatment had anti-cancer effects on NSCLC by blocking NADPH and ATP production. These findings emphasize the structure characterizing ALDH1L1 with gossypol.
Assuntos
Gossipol , Humanos , Gossipol/química , Gossipol/farmacologia , Gossipol/metabolismo , NADP/metabolismo , NADP/química , Modelos Moleculares , Microscopia Crioeletrônica , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Aldeído Oxirredutases/metabolismo , Aldeído Oxirredutases/química , Ligação Proteica , Sítios de Ligação , Sítio Alostérico , Conformação Proteica , Linhagem Celular Tumoral , Oxirredutases atuantes sobre Doadores de Grupo CH-NHRESUMO
Influenza A virus is the cause of a widespread human disease with high morbidity and mortality rates. The influenza virus encodes non-structural protein 1 (NS1), an exceedingly multifunctional virulence component. NS1 plays essential roles in viral replication and evasion of the cellular innate immune system. Protein kinase RNA-activated also known as protein kinase R (PKR) phosphorylates translation initiation factor eIF-2α on serine 51 to inhibit protein synthesis in virus-infected mammalian cells. Consequently, PKR activation inhibits mRNA translation, which results in the assert of both viral protein synthesis and cellular and possibly apoptosis in response to virus infection. Host signaling pathways are important in the replication of influenza virus, but the mechanisms involved remain to be characterized. Herein, the structure of NS1 and PKR complex was determined using Cryo-EM. We found the N91, E94, and G95 residues of PKR bind directly with N188, D125, and K126, respectively, of NS1. Furthermore, the study shows that PKR peptide offers a potential treatment for Influenza A virus infections.
Assuntos
Vírus da Influenza A , eIF-2 Quinase , Animais , Humanos , eIF-2 Quinase/metabolismo , Proteínas não Estruturais Virais/química , Vírus da Influenza A/genética , Microscopia Crioeletrônica , Linhagem Celular , Antivirais/metabolismo , Replicação Viral , Mamíferos/metabolismoRESUMO
T-cell immunoglobulin and mucin protein 3 (Tim-3), also known as Hepatitis A virus cellular receptor 2, has been discovered to have a negative regulatory effect on murine T-cell responses. Galectin-9 exhibits various biological effects, including cell aggregation, eosinophil chemoattraction, activation, and apoptosis, observed in murine thymocytes, T-cells, and human melanoma cells. Such approach demonstrated that Galectin-9 acts as a binding partner on Tim-3 and mediates the T-cell inhibitory effects. Tl-gal is a homologous protein to galectin-9, isolated from the adult stage of the canine gastrointestinal nematode parasite Toxascaris leonina. However, molecular mechanism between Tim-3 and galectin-9 is still remain unknown. Here, we describe the cryo-electron microscopy and X-ray structures and interactions of the Tim-3 and Tl-gal complex as well as their biochemical and biophysical characterization. In the structure, Ser46 residue of Tl-gal NCRD was bound to Asp25 residue of hTim-3. Compared to our previous study, the binding site of the complex is the same as the sugar binding site (the Ser46 residue) of Tl-gal. In addition, analysis of the complex structure revealed that the four Tl-gal molecules were in an open form packing and one mTim-3 peptide was bound to one Tl-gal molecule. These observations suggest that how Tl-gal binds hTim3 is essential to understanding the molecular mechanism for the Tim-3-galectin 9 interaction that regulates immune responses. This could potentially serve as a therapeutic target for inflammatory diseases.
Assuntos
Receptor Celular 2 do Vírus da Hepatite A , Toxascaris , Adulto , Camundongos , Animais , Humanos , Cães , Toxascaris/química , Toxascaris/metabolismo , Microscopia Crioeletrônica , Galectinas/metabolismo , Imunoglobulinas , MucinasRESUMO
E3L (RNA-binding protein E3) is one of the key IFN resistance genes encoded by VV and consists of 190 amino acids with a highly conserved carboxy-terminal double-stranded RNA-binding domain (dsRBD). PKR (dsRNA-dependent protein kinase) is an IFN-induced protein involved in anti-cell and antiviral activity. PKR inhibits the initiation of translation through alpha subunit of the initiation factor eIF2 (eIF2α) and mediates several transcription factors such as NF-κB, p53 or STATs. Activated PKR also induces apoptosis in vaccinia virus infection. E3L is required for viral IFN resistance and directly binds to PKR to block activation of PKR. In this work, we determined the three-dimensional complex structure of E3L and PKR using cryo-EM and determined the important residues involved in the interaction. In addition, PKR peptide binds to E3L and can increase protein levels of phosphorus-PKR and phosphorus-eIF2α-induced cell apoptosis through upregulation of phosphorus-PKR in HEK293 cells. Taken together, structural insights into E3L and PKR will provide a new optimization and development of vaccinia virus drugs.
Assuntos
Vaccinia virus , Proteínas Virais , Humanos , eIF-2 Quinase/metabolismo , Células HEK293 , Fosforilação , RNA de Cadeia Dupla , Vaccinia virus/genética , Proteínas Virais/metabolismoRESUMO
KRAS mutations occur in a quarter of all human cancers. When activated in its GTP-bound form, RAS stimulates diverse cellular systems, such as cell division, differentiation, growth, and apoptosis through the activations of various signaling pathways, which include mitogen-activated protein kinase (MAPK), phosphoinositide 3 kinases (PI3K), and RAL-GEFs pathways. We found that GJ101 (65LYDVA69) binds directly to the KRAS mutant (G12V) and showed tumor-suppressive activity. In addition, the GJ101 peptide inhibited KRAS mutant as determined by a [α-32P] guanosine triphosphate (GTP) binding assay and suppressed pancreatic cell line in a cell proliferation assay. Herein, the complex structure of KRAS and GJ101 was clarified by X-ray crystallography. Isothermal titration calorimetry showed that GJ101 binds highly with KRAS mutant and the complex structure of KRAS G12V.GJ101 complex presented that the residue of Q61 directly interacted with L65 of GJ101. Overall, the results suggest GJ101 be considered a developmental starting point for KRAS G12V inhibitor.
Assuntos
Proteínas Proto-Oncogênicas p21(ras) , Transdução de Sinais , Humanos , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Linhagem Celular , Mutação , Guanosina Trifosfato/metabolismo , Linhagem Celular TumoralRESUMO
Fas-associated death domain (FADD) is an adapter molecule that bridges the interaction between receptor-interacting protein 1 (RIP1) and aspartate-specific cysteine protease-8 (caspase-8). As the primary mediator of apoptotic cell death, caspase-8 has two N-terminal death-effector domains (DEDs) and it interacts with other proteins in the DED subfamily through several conserved residues. In the tumor necrosis receptor-1 (TNFR-1)-dependent signaling pathway, apoptosis is triggered by the caspase-8/FADD complex by stimulating receptor internalization. However, the molecular mechanism of complex formation by the DED proteins remains poorly understood. Here, we found that direct DED-DED interaction between FADD and caspase-8 and the structure-based mutations (Y8D/I128A, E12A/I128A, E12R/I128A, K39A/I128A, K39D/I128A, F122A/I128A, and L123A/I128A) of caspase-8 disrupted formation of the stable DED complex with FADD. Moreover, the monomeric crystal structure of the caspase-8 DEDs (F122A/I128A) was solved at 1.7 Å. This study will provide new insight into the interaction mechanism and structural characteristics between FADD and caspase-8 DED subfamily proteins.
Assuntos
Apoptose , Caspase 8 , Caspase 9 , Proteína de Domínio de Morte Associada a FasRESUMO
PURPOSE: We aimed to investigate the association between air pollution concentration levels and hospital admissions for heart failure (HF) among older adults in metropolitan cities in South Korea. METHODS: We used hospital admission data of 1.8 million older adults in seven metropolitan cities from 2008 to 2016, derived from the National Health Insurance Service of South Korea. Daily HF admission data were linked to air pollutants concentrations for the respective dates, including particulate matter less than 2.5 µm in size (PM2.5), 10 µm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone. We estimated the association between air pollutants and daily HF admissions using quasi-Poisson generalized additive models for each city. RESULTS: During the study period, 142,490 hospital admissions for HF were noted. Increases of 10 µg/m3 of PM2.5 and PM10, and 10 ppb of SO2, NO2, and CO were associated with an increased risk of HF admission by 0.93% ([95% confidence intervals 0.51-1.36], 0.55% [0.31-0.80], 6.04% [2.15-10.08], 1.10% [0.38-1.82], and 0.05% [0.01-0.09]), respectively, on the same day. Increases in mean exposure to PM2.5, PM10, and SO2 for 8 days from the concurrent day were also significantly associated with HF admissions. During the warm season, the risk of HF admissions increased shortly after an increase in PM2.5, whereas prolonged effects were observed during the cold season. CONCLUSION: Our study suggests the adverse effects of air pollution on HF. Moreover, the evidence of seasonality may help tailor protection guidelines for older adults.
Assuntos
Poluição do Ar/análise , Exposição Ambiental , Insuficiência Cardíaca/epidemiologia , Hospitalização/estatística & dados numéricos , Poluentes Atmosféricos/análise , Monóxido de Carbono/análise , Cidades/epidemiologia , Humanos , Dióxido de Nitrogênio/análise , Ozônio/análise , Material Particulado/análise , República da Coreia/epidemiologia , Estações do Ano , Dióxido de Enxofre/análiseRESUMO
The KRAS oncogene is mutated in approximately ~30% of human cancers, and the targeting of KRAS has long been highlighted in many studies. Nevertheless, attempts to target KRAS directly have been ineffective. This review provides an overview of the structure of KRAS and its characteristic signaling pathways. Additionally, we examine the problems associated with currently available KRAS inhibitors and discuss promising avenues for drug development.
Assuntos
Antineoplásicos/farmacologia , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Animais , Humanos , Modelos Biológicos , Neoplasias/metabolismo , Neoplasias/patologia , Proteínas Proto-Oncogênicas p21(ras)/química , Transdução de SinaisRESUMO
PUMA (p53-upregulated modulator of apoptosis) is localized in mitochondria and a direct target in p53-mediated apoptosis. p53 elicits mitochondrial apoptosis via transcription-dependent and independent mechanisms. p53 is known to induce apoptosis via the transcriptional induction of PUMA, which encodes proapoptotic BH3-only members of the Bcl-2 protein family. However, the transcription-independent mechanisms of human PUMA remain poorly defined. For example, it is not known whether PUMA interacts directly with the DNA binding domain (DBD: residues 92-293) of p53 in vitro. Here, the structure of the complex between the DBD of p53 and PUMA peptide was elucidated by X-ray crystallography. Isothermal titration calorimetry showed that PUMA peptide binds strongly with p53 DBD, and the crystal structure of p53-PUMA peptide complex revealed it contains four molecules of p53 DBD and one PUMA peptide per asymmetric unit in space group P1. PUMA peptide bound to the N-terminal residues of p53 DBD. A cell proliferation assay demonstrated PUMA peptide inhibited the growth of a lung cancer cell line. These results contribute to understanding of the mechanism responsible for p53-mediated apoptosis.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , DNA/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteína Supressora de Tumor p53/química , Proteína Supressora de Tumor p53/metabolismo , Sequência de Aminoácidos , Proteínas Reguladoras de Apoptose/química , Calorimetria , Humanos , Ligação Proteica , Domínios Proteicos , Proteínas Proto-Oncogênicas/química , Eletricidade Estática , Zinco/metabolismoRESUMO
RATIONALE: Although an association of fine particulate matter (PM2.5) with asthma incidence has been assumed, there is insufficient evidence regarding the effect of long-term exposure to PM2.5 on incident asthma among elderly adults. OBJECTIVES: This study aimed to investigate an association between long-term exposure to PM2.5 and incident asthma among elderly adults in South Korea. METHODS: Adults ≥65 years of age (n = 1,220,645) who did not visit hospitals for asthma during a washout period (between 2008 and 2010) were followed up until 2016 using data from the National Health Insurance System in South Korea. Incident asthma was defined as the number of patients with a primary diagnostic code of asthma who visited hospitals more than twice. We linked the health data with district-level PM2.5 concentrations and estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for incident asthma after adjusting for potential confounders in time-varying Cox proportional hazard models. MEASUREMENTS AND MAIN RESULTS: Over 5,942,256 person-years, 54,522 patients developed asthma, with an incidence of 9.2 cases/1000 person-years. A 10 µg/m3 increase in the 36-month mean PM2.5 concentration was significantly associated with a 9% increase in incident asthma (HR = 1.09, 95% CI: 1.04-1.14). This association was found to be robust for different definitions of incident asthma and washout periods. CONCLUSION: Long-term exposure to PM2.5 was associated with the incidence of asthma in elderly adults. This finding provides evidence of an association between PM2.5 and adult-onset asthma.
Assuntos
Poluentes Atmosféricos , Poluição do Ar , Asma , Adulto , Idoso , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , Asma/induzido quimicamente , Asma/epidemiologia , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Humanos , Incidência , Material Particulado/efeitos adversos , Material Particulado/análise , República da Coreia/epidemiologiaRESUMO
Most cancer cells primarily produce their energy through a high rate of glycolysis followed by lactic acid fermentation even in the presence of abundant oxygen. Pyruvate dehydrogenase kinase (PDK) 1, an enzyme responsible for aerobic glycolysis via phosphorylating and inactivating pyruvate dehydrogenase (PDH) complex, is commonly overexpressed in tumors and recognized as a therapeutic target in colorectal cancer. Hemistepsin A (HsA) is a sesquiterpene lactone isolated from Hemistepta lyrata Bunge (Compositae). Here, we report that HsA is a PDK1 inhibitor can reduce the growth of colorectal cancer and consequent activation of mitochondrial ROS-dependent apoptotic pathway both in vivo and in vitro. Computational simulation and biochemical assays showed that HsA directly binds to the lipoamide-binding site of PDK1, and subsequently inhibits the interaction of PDK1 with the E2 subunit of PDH complex. As a result of PDK1 inhibition, lactate production was decreased, but oxygen consumption was increased. Mitochondrial ROS levels and mitochondrial damage were also increased. Consistent with these observations, the apoptosis of colorectal cancer cells was promoted by HsA with enhanced activation of caspase-3 and -9. These results suggested that HsA might be a potential candidate for developing a novel anti-cancer drug through suppressing cancer metabolism.
Assuntos
Neoplasias Colorretais/enzimologia , Inibidores Enzimáticos , Lactonas , Proteínas de Neoplasias , Piruvato Desidrogenase Quinase de Transferência de Acetil , Sesquiterpenos , Sítios de Ligação , Linhagem Celular Tumoral , Neoplasias Colorretais/patologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Humanos , Lactonas/química , Lactonas/farmacologia , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/química , Proteínas de Neoplasias/metabolismo , Piruvato Desidrogenase Quinase de Transferência de Acetil/antagonistas & inibidores , Piruvato Desidrogenase Quinase de Transferência de Acetil/química , Piruvato Desidrogenase Quinase de Transferência de Acetil/metabolismo , Sesquiterpenos/química , Sesquiterpenos/farmacologiaRESUMO
The Medical Information Department of a pharmaceutical manufacturer provides written scientific responses to unsolicited requests from healthcare providers for information on products that extends beyond the product labeling (off-label). These scientific response documents are non-promotional, evidence-based, and scientifically balanced, conforming with internal pharmaceutical manufacturer's procedures and the Food and Drug Administration (FDA) Draft Guidance on Responding to Unsolicited Requests for Off-Label Information. Members of phactMI™ developed this proposal to offer best practices for content generation of scientific response documents. Scientific response documents review available literature to respond to an unsolicited request; therefore, they are similar in nature to systematic reviews. The sections and elements identified in this proposed best practice guidelines for scientific response documents are based on an adaptation of the sections and elements of systematic reviews. The sections of a scientific response document should include a restatement of the unsolicited request (title); a structured summary (abstract); approved indications, black box warnings, and background information when appropriate (introduction); the literature search information and study selection (methods); summation of data from clinical trials, meta-analysis, case reports, and/or real world evidence, as appropriate (results); treatment guidelines, if applicable and available (discussion); and references. Elements for each section should be included in a scientific response document as appropriate, as some elements are not necessary in some documents, based on the question. These elements were selected for inclusion to address any potential concerns of bias and transparency and reflect the intent that scientific response documents should be non-promotional, accurate, truthful, free of commercial bias, scientifically balanced, and evidence based.
Assuntos
Preparações Farmacêuticas , Consenso , Pessoal de Saúde , HumanosRESUMO
In cancer cells, aerobic glycolysis rather than oxidative phosphorylation (OxPhos) is generally preferred for the production of ATP. In many cancers, highly expressed pyruvate dehydrogenase kinase 1 (PDK1) reduces the activity of pyruvate dehydrogenase (PDH) by inducing the phosphorylation of its E1α subunit (PDHA1) and subsequently, shifts the energy metabolism from OxPhos to aerobic glycolysis. Thus, PDK1 has been regarded as a target for anticancer treatment. Here, we report that ilimaquinone (IQ), a sesquiterpene quinone isolated from the marine sponge Smenospongia cerebriformis, might be a novel PDK1 inhibitor. IQ decreased the cell viability of human and murine cancer cells, such as A549, DLD-1, RKO, and LLC cells. The phosphorylation of PDHA1, the substrate of PDK1, was reduced by IQ in the A549 cells. IQ decreased the levels of secretory lactate and increased oxygen consumption. The anticancer effect of IQ was markedly reduced in PDHA1-knockout cells. Computational simulation and biochemical assay revealed that IQ interfered with the ATP binding pocket of PDK1 without affecting the interaction of PDK1 and the E2 subunit of the PDH complex. In addition, similar to other pyruvate dehydrogenase kinase inhibitors, IQ induced the generation of mitochondrial reactive oxygen species (ROS) and depolarized the mitochondrial membrane potential in the A549 cells. The apoptotic cell death induced by IQ treatment was rescued in the presence of MitoTEMPO, a mitochondrial ROS inhibitor. In conclusion, we suggest that IQ might be a novel candidate for anticancer therapeutics that act via the inhibition of PDK1 activity.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Piruvato Desidrogenase Quinase de Transferência de Acetil/metabolismo , Quinonas/farmacologia , Sesquiterpenos/farmacologia , Células A549 , Trifosfato de Adenosina/metabolismo , Animais , Apoptose/fisiologia , Carcinoma Pulmonar de Lewis , Linhagem Celular Tumoral , Humanos , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Fosforilação/efeitos dos fármacos , Poríferos/química , Piruvato Desidrogenase (Lipoamida)/genética , Piruvato Desidrogenase (Lipoamida)/metabolismo , Piruvato Desidrogenase Quinase de Transferência de Acetil/antagonistas & inibidores , Piruvato Desidrogenase Quinase de Transferência de Acetil/química , Espécies Reativas de Oxigênio/metabolismoAssuntos
Carcinoma Mucoepidermoide/diagnóstico , Citodiagnóstico , Eosinofilia/diagnóstico , Neoplasias da Glândula Tireoide/diagnóstico , Adulto , Biópsia por Agulha Fina , Carcinoma Mucoepidermoide/patologia , Eosinofilia/patologia , Feminino , Humanos , Glândula Tireoide/diagnóstico por imagem , Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/patologiaRESUMO
Kirsten-RAS (KRAS) has been the target of drugs because it is the most mutated gene in human cancers. Because of the low affinity of drugs for KRAS mutations, it was difficult to target these tumor genes directly. We found a direct interaction between KRAS G12V and tumor suppressor novel H-REV107 peptide with high binding affinity. We report the first crystal structure of an oncogenic mutant, KRAS G12V-H-REV107. This peptide was shown to interact with KRAS G12V in the guanosine diphosphate (GDP)-bound inactive state and to form a stable complex, blocking the activation function of KRAS. We showed that the peptide acted as an inhibitor of mutant KRAS targets by [α-32P] guanosine triphosphate (GTP) binding assay. The H-REV107 peptide inhibited pancreatic cancer and colon cancer cell lines in cell proliferation assay. Specially, the H-REV107 peptide can suppress pancreatic tumor growth by reduction of tumor volume and weight in xenotransplantation mouse models. Overall, the results presented herein will facilitate development of novel drugs for inhibition of KRAS mutations in cancer patients.
RESUMO
Angiogenesis should be precisely regulated because disordered neovascularization is involved in the aggravation of multiple diseases. The vascular endothelial growth factor (VEGF)-A/VEGF receptor 2 (VEGFR-2) axis is crucial for controlling angiogenic responses in vascular endothelial cells (ECs). Therefore, inactivating VEGFR-2 signaling may effectively suppress aberrant angiogenesis and alleviate related symptoms. In this study, we performed virtual screening, identified the synthetic disaccharide 6'-sialylgalactose (6SG) as a potent VEGFR-2-binding compound and verified its high binding affinity by Biacore assay. 6SG effectively suppressed VEGF-A-induced VEGFR-2 phosphorylation and subsequent in vitro angiogenesis in HUVECs without inducing cytotoxicity. 6SG also inhibited VEGF-A-induced extracellular-regulated kinase (ERK)/Akt activation and actin stress fiber formation in HUVECs. We demonstrated that 6SG inhibited retinal angiogenesis in a mouse model of retinopathy of prematurity and tumor angiogenesis in a xenograft mouse model. Our results suggest a potential therapeutic benefit of 6SG in inhibiting angiogenesis in proangiogenic diseases, such as retinopathy and cancer.
Assuntos
Galactose/metabolismo , Neoplasias/genética , Neovascularização Patológica/genética , Fator A de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Inibidores da Angiogênese/metabolismo , Animais , Movimento Celular/genética , Proliferação de Células/genética , Células Cultivadas , Galactose/análogos & derivados , Xenoenxertos , Células Endoteliais da Veia Umbilical Humana , Humanos , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Neoplasias/patologia , Neovascularização Patológica/metabolismo , Fosforilação/genética , Retinopatia da Prematuridade/genética , Retinopatia da Prematuridade/patologia , Transdução de Sinais/genética , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidoresRESUMO
Lactate dehydrogenase A (LDHA) is an important enzyme responsible for cancer growth and energy metabolism in various cancers via the aerobic glycolytic pathway. Here, we report that machilin A (MA), which acts as a competitive inhibitor by blocking the nicotinamide adenine dinucleotide (NAD) binding site of LDHA, suppresses growth of cancer cells and lactate production in various cancer cell types, including colon, breast, lung, and liver cancers. Furthermore, MA markedly decreased LDHA activity, lactate production, and intracellular adenosine triphosphate (ATP) levels induced by hypoxia-induced LDHA expression in cancer cells, and significantly inhibited colony formation, leading to reduced cancer cell survival. In mouse models inoculated with murine Lewis lung carcinoma, MA significantly suppressed tumor growth as observed by a reduction of tumor volume and weight; resulting from the inhibition of LDHA activity. Subsequently, the suppression of tumor-derived lactic acid in MA-treated cancer cells resulted in decrease of neovascularization through the regulation of alternatively activated macrophages (M2) polarization in macrophages. Taken together, we suggest that the reduction of lactate by MA in cancer cells directly results in a suppression of cancer cell growth. Furthermore, macrophage polarization and activation of endothelial cells for angiogenesis were indirectly regulated preventing lactate production in MA-treated cancer cells.
RESUMO
The influenza A virus is a highly infectious respiratory pathogen that sickens many people with respiratory disease annually. To prevent outbreaks of this viral infection, an understanding of the characteristics of virus-host interaction and development of an anti-viral agent is urgently needed. The influenza A virus can infect mammalian species including humans, pigs, horses and seals. Furthermore, this virus can switch hosts and form a novel lineage. This so-called zoonotic infection provides an opportunity for virus adaptation to the new host and leads to pandemics. Most influenza A viruses express proteins that antagonize the antiviral defense of the host cell. The non-structural protein 1 (NS1) of the influenza A virus is the most important viral regulatory factor controlling cellular processes to modulate host cell gene expression and double-stranded RNA (dsRNA)-mediated antiviral response. This review focuses on the influenza A virus NS1 protein and outlines current issues including the life cycle of the influenza A virus, structural characterization of the influenza A virus NS1, interaction between NS1 and host immune response factor, and design of inhibitors resistant to the influenza A virus.
Assuntos
Vírus da Influenza A/genética , Proteínas não Estruturais Virais/genética , Sequência de Aminoácidos , Animais , Antivirais/farmacologia , Regulação Viral da Expressão Gênica , Interações Hospedeiro-Patógeno , Humanos , Imunidade Inata , Vírus da Influenza A/fisiologia , Infecções por Orthomyxoviridae/tratamento farmacológico , Infecções por Orthomyxoviridae/prevenção & controle , Conformação Proteica , RNA de Cadeia Dupla/genética , RNA de Cadeia Dupla/isolamento & purificação , Proteínas não Estruturais Virais/metabolismo , Replicação ViralRESUMO
Aerobic glycolysis is one of the important metabolic characteristics of many malignant tumors. Pyruvate dehydrogenase kinase (PDHK) plays a key role in aerobic glycolysis by phosphorylating the E1α subunit of pyruvate dehydrogenase (PDH). Hence, PDHK has been recognized as a molecular target for cancer treatment. Here, we report that huzhangoside A (Hu.A), a triterpenoid glycoside compound isolated from several plants of the Anemone genus, acts as a novel PDHK inhibitor. Hu.A was found to decrease the cell viability of human breast cancer MDA-MB-231, hepatocellular carcinoma Hep3B, colon cancer HT-29, DLD-1, and murine lewis lung carcinoma LLC cell lines. The activity of PDHK1 was decreased by Hu.A in both in vitro assays and in vivo assays in DLD-1 cells. Hu.A significantly increased the oxygen consumption and decreased the secretory lactate levels in DLD-1 cells. In addition, Hu.A interacted with the ATP-binding pocket of PDHK1 without affecting the interaction of PDHK1 and pyruvate dehydrogenase complex (PDC) subunits. Furthermore, Hu.A significantly induced mitochondrial reactive oxygen species (ROS) and depolarized the mitochondrial membrane potential in DLD-1 cells. Consistently, when Hu.A was intraperitoneally injected into LLC allograft mice, the tumor growth was significantly decreased. In conclusion, Hu.A suppressed the growth of tumors in both in vitro and in vivo models via inhibition of PDHK activity.