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1.
Emerg Microbes Infect ; 8(1): 734-748, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31130074

RESUMO

Many pathogens infect hosts through various immune evasion strategies. However, the molecular mechanisms by which pathogen proteins modulate and evade the host immune response remain unclear. Enterohemorrhagic Escherichia coli (EHEC) is a pathological strain that can induce mitogen-activated protein (MAP) kinase (Erk, Jnk and p38 MAPK) and NF-κB pathway activation and proinflammatory cytokine production, which then causes diarrheal diseases such as hemorrhagic colitis and hemolytic uremic syndrome. Transforming growth factor ß-activated kinase-1 (TAK1) is a key regulator involved in distinct innate immune signalling pathways. Here we report that EHEC translocated intimin receptor (Tir) protein inhibits the expression of EHEC-induced proinflammatory cytokines by interacting with the host tyrosine phosphatase SHP-1, which is dependent on the phosphorylation of immunoreceptor tyrosine-based inhibition motifs (ITIMs). Mechanistically, the association of EHEC Tir with SHP-1 facilitated the recruitment of SHP-1 to TAK1 and inhibited TAK1 phosphorylation, which then negatively regulated K63-linked polyubiquitination of TAK1 and downstream signal transduction. Taken together, these results suggest that EHEC Tir negatively regulates proinflammatory responses by inhibiting the activation of TAK1, which is essential for immune evasion and could be a potential target for the treatment of bacterial infection.


Assuntos
Escherichia coli Êntero-Hemorrágica/patogenicidade , Infecções por Escherichia coli/fisiopatologia , Proteínas de Escherichia coli/metabolismo , Interações Hospedeiro-Patógeno , Evasão da Resposta Imune , MAP Quinase Quinase Quinases/antagonistas & inibidores , Receptores de Superfície Celular/metabolismo , Fatores de Virulência/metabolismo , Animais , Infecções por Escherichia coli/microbiologia , Células HEK293 , Humanos , Macrófagos Peritoneais , Camundongos , Camundongos Endogâmicos C57BL , Ligação Proteica , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Células RAW 264.7
2.
Thyroid ; 29(6): 809-823, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30924726

RESUMO

Background: Anaplastic thyroid carcinoma (ATC) is one of the most aggressive malignancies, with no effective treatment currently available. The molecular mechanisms of ATC carcinogenesis remain poorly understood. The objective of this study was to investigate the mechanisms and functions of super-enhancer (SE)-driven oncogenic transcriptional addiction in the progression of ATC and identify new drug targets for ATC treatments. Methods: High-throughput chemical screening was performed to identify new drugs inhibiting ATC cell growth. Cell viability assay, colony formation analysis, cell-cycle analysis, and animal study were used to examine the effects of drug treatments on ATC progression. Chromatin immunoprecipitation sequencing was conducted to establish a SE landscape of ATC. Integrative analysis of RNA sequencing, chromatin immunoprecipitation sequencing, and CRISPR/Cas9-mediated gene editing was used to identify THZ1 target genes. Drug combination analysis was performed to assess drug synergy. Patient samples were analyzed to evaluate candidate biomarkers of prognosis in ATC. Results: THZ1, a covalent inhibitor of cyclin-dependent kinase 7 (CDK7), was identified as a potent anti-ATC compound by high-throughput chemical screening. ATC cells, but not papillary thyroid carcinoma cells, are exceptionally sensitive to CDK7 inhibition. An integrative analysis of both gene expression profiles and SE features revealed that the SE-mediated oncogenic transcriptional amplification mediates the vulnerability of ATC cells to THZ1 treatment. Combining this integrative analysis with functional assays led to the discovery of a number of novel cancer genes of ATC, including PPP1R15A, SMG9, and KLF2. Inhibition of PPP1R15A with Guanabenz or Sephin1 greatly suppresses ATC growth. Significantly, the expression level of PPP1R15A is correlated with CDK7 expression in ATC tissue samples. Elevated expression of PPP1R15A and CDK7 are both associated with poor clinical prognosis in ATC patients. Importantly, CDK7 or PPP1R15A inhibition sensitizes ATC cells to conventional chemotherapy. Conclusions: Taken together, these findings demonstrate transcriptional addiction in ATC pathobiology and identify CDK7 and PPP1R15A as potential biomarkers and therapeutic targets for ATC.

3.
Nucleic Acids Res ; 46(W1): W114-W120, 2018 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-29771388

RESUMO

Genome-wide association studies have generated over thousands of susceptibility loci for many human complex traits, and yet for most of these associations the true causal variants remain unknown. Tissue/cell type-specific prediction and prioritization of non-coding regulatory variants will facilitate the identification of causal variants and underlying pathogenic mechanisms for particular complex diseases and traits. By leveraging recent large-scale functional genomics/epigenomics data, we develop an intuitive web server, GWAS4D (http://mulinlab.tmu.edu.cn/gwas4d or http://mulinlab.org/gwas4d), that systematically evaluates GWAS signals and identifies context-specific regulatory variants. The updated web server includes six major features: (i) updates the regulatory variant prioritization method with our new algorithm; (ii) incorporates 127 tissue/cell type-specific epigenomes data; (iii) integrates motifs of 1480 transcriptional regulators from 13 public resources; (iv) uniformly processes Hi-C data and generates significant interactions at 5 kb resolution across 60 tissues/cell types; (v) adds comprehensive non-coding variant functional annotations; (vi) equips a highly interactive visualization function for SNP-target interaction. Using a GWAS fine-mapped set for 161 coronary artery disease risk loci, we demonstrate that GWAS4D is able to efficiently prioritize disease-causal regulatory variants.

4.
Free Radic Biol Med ; 120: 1-12, 2018 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-29524606

RESUMO

Metabolic reprogramming is a hallmark of cancer. Glycine decarboxylase (GLDC), an oxidoreductase, plays an important role in amino acid metabolism. While GLDC promotes tumor initiation and proliferation in non-small cell lung cancer and glioma and it was reported as a putative tumor suppressor gene in gastric cancer, the role of GLDC in hepatocellular carcinoma (HCC) is unknown. In the current study, microarray-based analysis suggested that GLDC expression was low in highly malignant HCC cell lines, and clinicopathological analysis revealed a decrease in GLDC in HCC tumor samples. While the knockdown of GLDC enhanced cancer cell migration and invasion, GLDC overexpression inhibited them. Mechanistic studies revealed that GLDC knockdown increased the levels of reactive oxygen species (ROS) and decreased the ratio of glutathione/oxidized glutathione (GSH/GSSG), which in turn dampened the ubiquitination of cofilin, a key regulator of actin polymerization. Consequently, the protein level of cofilin was elevated, which accounted for the increase in cell migration. The overexpression of GLDC reversed the phenotype. Treatment with N-acetyl-L-cysteine decreased the protein level of cofilin while treatment with H2O2 increased it, further confirming the role of ROS in regulating cofilin degradation. In a tumor xenographic transplant nude mouse model, the knockdown of GLDC promoted intrahepatic metastasis of HCC while GLDC overexpression inhibited it. Our data indicate that GLDC downregulation decreases ROS-mediated ubiquitination of cofilin to enhance HCC progression and intrahepatic metastasis.

5.
Mol Cell Proteomics ; 17(4): 607-618, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29371291

RESUMO

The systematic investigation of gene mutation and expression is important to discover novel biomarkers and therapeutic targets in cancers. Here, we integrated genomics, transcriptomics, proteomics, and metabolomics to analyze three hepatocellular carcinoma (HCC) cell lines with differential metastatic potentials. The results revealed the profile of the prometastasis metabolism potentially associated with HCC metastasis. The multiomic analysis identified 12 genes with variations at multiple levels from three metabolic pathways, including glycolysis, starch, and sucrose metabolism, and glutathione metabolism. Furthermore, uridine diphosphate (UDP)-glucose pyrophosphorylase 2 (UGP2), was observed to be persistently up-regulated with increased metastatic potential. UGP2 overexpression promoted cell migration and invasion and enhanced glycogenesis in vitro The role of UGP2 in metastasis was further confirmed using a tumor xenograft mouse model. Taken together, the compendium of multiomic data provides valuable insights in understanding the roles of shifted cellular metabolism in HCC metastasis.

6.
Biomed Rep ; 4(4): 493-497, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27073640

RESUMO

The aim of the present study was to assess the anti-hepatitis B virus (HBV) effect of Cimicifuga foetida L. (C. foetida) in the patients with chronic hepatitis B (CHB). A total of 60 randomly selected patients with CHB were recruited and divided into groups I and II. The patients in group I received a monotherapy of adefovir (ADV), and the patients in group II received a combination therapy of ADV and C. foetida for >48 weeks. Intrahepatic (IH) HBV covalently closed circular DNA (cccDNA), serum HBV DNA, hepatitis B surface antigen (HBsAg), alanine aminotransferase levels and serum interferon-γ (IFN-γ) and transforming growth factor-ß (TGF-ß) levels were quantified during the test. Following the treatment, a significant reduction of the median IH cccDNA level was identified in group II (P=0.017), but not in group I (P=0.05, and P=0.01 between the 2 groups), and a significant reduction of log10 HBsAg was identified in groups I (P=0.012) and II (P<0.0001, and P=0.20 between the 2 groups). A significant increase of the median serum IFN-γ level was found in group II (P=0.0005), but not in group I (P=0.06, and P=0.004 between the 2 groups), and a significant reduction of the median TGF-ß level was identified in groups I (P<0.0001) and II (P<0.0001, and P=0.002 between the 2 groups). A total of 24 patients in group I, and 27 patients in group II achieved a sustained virological response (P=0.0386), and 20 patients in group I and 24 in group II achieved hepatitis B e antigen seroclearance (P=0.0442). In conclusion, C. foetida can effectively inhibit HBV transcription and replication in the patients by stimulating the release of the inflammatory cytokines, such as IFN-γ.

7.
Nucleic Acids Res ; 44(10): 4934-46, 2016 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-27016738

RESUMO

Mitotic chromosomes are one of the most commonly recognized sub-cellular structures in eukaryotic cells. Yet basic information necessary to understand their structure and assembly, such as their composition, is still lacking. Recent proteomic studies have begun to fill this void, identifying hundreds of RNA-binding proteins bound to mitotic chromosomes. However, by contrast, there are only two RNA species (U3 snRNA and rRNA) that are known to be associated with the mitotic chromosome, suggesting that there are many mitotic chromosome-associated RNAs (mCARs) not yet identified. Here, using a targeted protocol based on 5'-tag sequencing to profile the mammalian mCAR population, we report the identification of 1279 mCARs, the majority of which are ncRNAs, including lncRNAs that exhibit greater conservation across 60 vertebrate species than the entire population of lncRNAs. There is also a significant enrichment of snoRNAs and specific SINE RNAs. Finally, ∼40% of the mCARs are presently unannotated, many of which are as abundant as the annotated mCARs, suggesting that there are also many novel ncRNAs in the mCARs. Overall, the mCARs identified here, together with the previous proteomic and genomic data, constitute the first comprehensive catalogue of the molecular composition of the eukaryotic mitotic chromosomes.


Assuntos
Cromossomos de Mamíferos/química , Mitose/genética , RNA não Traduzido/análise , Células 3T3 , Animais , Sequenciamento de Nucleotídeos em Larga Escala , Metáfase/genética , Camundongos , RNA não Traduzido/química , RNA não Traduzido/isolamento & purificação , Análise de Sequência de RNA , Sitios de Sequências Rotuladas
8.
Sci Rep ; 5: 16938, 2015 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-26582414

RESUMO

Questions remain about the significance of the dose-response relationship between body mass index (BMI) and lung cancer (LC) risk. Pertinent studies were identified through a search in EMBASE and PUBMED from July 2014 until March 2015. The summary relative risk (SRR) and confidence interval (CI) were estimated. The dose-response relationship was assessed using a restricted cubic spline. The overall meta-analysis showed evidence of a nonlinear association between BMI and LC risk (Pnonlinearity < 0.001). The SRR were 0.98 (95%CI: 0.95-1.01) for 25 kg/m(2), 0.91 (95%CI: 0.85-0.98) for 30 kg/m(2) and 0.81 (95% CI: 0.72-0.91) for 35 kg/m(2), with mild between-study heterogeneity (I(2) = 5%). The results of the stratified analysis by gender were comparable to those of the overall meta-analysis. When stratified by smoking status, linear dose-response associations were observed for current smokers, ex-smokers and non-smokers (Pnonlinearity > 0.05), whereas the effects were attenuated when restricting analysis to non-smokers, and at the point of 30 kg/m(2), the SRR was 0.96 (95%CI: 0.86-1.07) for males and 0.95 (95%CI: 0.89-1.02) for females. This meta-analysis provides quantitative evidence that increasing BMI is a protective factor against LC. Keeping normal-to-moderate BMI should be prescribed as an evidence-based lifestyle tip for LC prevention in smokers.


Assuntos
Índice de Massa Corporal , Neoplasias Pulmonares/epidemiologia , Estudos de Coortes , Intervalos de Confiança , Feminino , Heterogeneidade Genética , Humanos , Masculino , Sobrepeso/complicações , Viés de Publicação , Fatores de Risco , Magreza/complicações
9.
Biomed Res Int ; 2014: 469103, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25093167

RESUMO

BACKGROUND: Lung cancer is the most important cause of cancer mortality worldwide, but the underlying mechanisms of this disease are not fully understood. Copy number variations (CNVs) are promising genetic variations to study because of their potential effects on cancer. METHODOLOGY/PRINCIPAL FINDINGS: Here we conducted a pilot study in which we systematically analyzed the association of CNVs in two lung cancer datasets: the Environment And Genetics in Lung cancer Etiology (EAGLE) and the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial datasets. We used a preestablished association method to test the datasets separately and conducted a combined analysis to test the association accordance between the two datasets. Finally, we identified 167 risk SNP loci and 22 CNVs associated with lung cancer and linked them with recombination hotspots. Functional annotation and biological relevance analyses implied that some of our predicted risk loci were supported by other studies and might be potential candidate loci for lung cancer studies. CONCLUSIONS/SIGNIFICANCE: Our results further emphasized the importance of copy number variations in cancer and might be a valuable complement to current genome-wide association studies on cancer.


Assuntos
Variações do Número de Cópias de DNA/genética , Estudo de Associação Genômica Ampla , Neoplasias Pulmonares/genética , Polimorfismo de Nucleotídeo Único/genética , Humanos , Neoplasias Pulmonares/patologia , Risco
10.
Sci Rep ; 4: 6036, 2014 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-25112956

RESUMO

Lung cancer is the most common cause of cancer mortality worldwide, with an estimated 1.4 million deaths each year. Here we report whole-exome sequencing of nine tumor/normal tissue pairs from Chinese patients with non-small cell lung carcinoma (NSCLC). This allows us to identify a number of significantly mutated genes in NSCLC, which were highly enriched in DNA damage repair, NF-κB pathway, JAK/STAT signaling and chromatin modification. Notably, we identify a histone-lysine methyltransferase gene, namely, MLL2, as one of the most significantly mutated genes in our screen. In a following validation study, we identify deleterious mutations of MLL2 in 12 out of 105 (11.4%) NSCLC patients. Additionally, reduced or lost expression of MLL2 was commonly observed in tumor tissues as compared with paired adjacent non-tumor tissues regardless of mutation status. Together, our study defines the landscape of somatic mutations in Chinese NSCLC and supports the role of MLL2 mutation in the pathogenesis of the disease.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Proteínas de Ligação a DNA/genética , Neoplasias Pulmonares/genética , Proteínas de Neoplasias/genética , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/patologia , China , Humanos , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Taxa de Mutação , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Análise de Sobrevida
11.
Protein Pept Lett ; 19(1): 79-90, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21919856

RESUMO

The DNA of all eukaryotic organisms is packaged into nucleosomes (a basic repeating unit of chromatin). A nucleosome consists of histone octamer wrapped by core DNA and linker histone H1 associated with linker DNA. It has profound effects on all DNA-dependent processes by affecting sequence accessibility. Understanding the factors that influence nucleosome positioning has great help to the study of genomic control mechanism. Among many determinants, the inherent DNA sequence has been suggested to have a dominant role in nucleosome positioning in vivo. Here, we used the method of minimum redundancy maximum relevance (mRMR) feature selection and the nearest neighbor algorithm (NNA) combined with the incremental feature selection (IFS) method to identify the most important sequence features that either favor or inhibit nucleosome positioning. We analyzed the words of 53,021 nucleosome DNA sequences and 50,299 linker DNA sequences of Saccharomyces cerevisiae. 32 important features were abstracted from 5,460 features, and the overall prediction accuracy through jackknife cross-validation test was 76.5%. Our results support that sequence-dependent DNA flexibility plays an important role in positioning nucleosome core particles and that genome sequence facilitates the rapid nucleosome reassembly instead of nucleosome depletion. Besides, our results suggest that there exist some additional features playing a considerable role in discriminating nucleosome forming and inhibiting sequences. These results confirmed that the underlying DNA sequence plays a major role in nucleosome positioning.


Assuntos
DNA Fúngico/química , Nucleossomos/química , Saccharomyces cerevisiae/química , Análise de Sequência de DNA/métodos , Algoritmos , Sequência de Bases , Montagem e Desmontagem da Cromatina/genética , Biologia Computacional , Histonas/química , Histonas/genética , Dados de Sequência Molecular , Nucleossomos/genética , Valor Preditivo dos Testes , Saccharomyces cerevisiae/genética
12.
Mol Syst Biol ; 6: 442, 2010 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-21179015

RESUMO

Nonsense-mediated mRNA decay (NMD) is a surveillance system that eliminates transcripts with premature termination codons. In this study, we show that mRNAs targeted by NMD are also suppressed at the translational level. The low translational efficiency (TE) is a consequence of multiple features acting in concert, including low translation initiation rate, mediated by 5' secondary structure and by use of weak initiation sites, and low translation elongation speed, mediated by low codon usage bias. Despite low elongation rates, NMD transcripts show low ribosome density in the coding sequence, probably owing to low initiation rates, high abortion rates or rapid transit of the ribosome following initiation failure. The low TE is observed in the absence of NMD and is not explained by low transcript abundance. Translational inefficiency is flexible, such that NMD targets have increased TE upon starvation. We propose that the low TE predisposes to NMD and/or that it is part of a mechanism for regulation of NMD transcripts.


Assuntos
Códon sem Sentido/metabolismo , Regulação Fúngica da Expressão Gênica , Biossíntese de Proteínas , Estabilidade de RNA/genética , Saccharomyces cerevisiae/genética , Códon sem Sentido/antagonistas & inibidores , Modelos Genéticos , Fases de Leitura Aberta , Estrutura Secundária de Proteína , Ribossomos/genética , Ribossomos/metabolismo , Saccharomyces cerevisiae/metabolismo , Transcrição Genética
13.
PLoS One ; 5(9)2010 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-20824131

RESUMO

BACKGROUND: The DNA of all eukaryotic organisms is packaged into nucleosomes, the basic repeating units of chromatin. The nucleosome consists of a histone octamer around which a DNA core is wrapped and the linker histone H1, which is associated with linker DNA. By altering the accessibility of DNA sequences, the nucleosome has profound effects on all DNA-dependent processes. Understanding the factors that influence nucleosome positioning is of great importance for the study of genomic control mechanisms. Transcription factors (TFs) have been suggested to play a role in nucleosome positioning in vivo. PRINCIPAL FINDINGS: Here, the minimum redundancy maximum relevance (mRMR) feature selection algorithm, the nearest neighbor algorithm (NNA), and the incremental feature selection (IFS) method were used to identify the most important TFs that either favor or inhibit nucleosome positioning by analyzing the numbers of transcription factor binding sites (TFBSs) in 53,021 nucleosomal DNA sequences and 50,299 linker DNA sequences. A total of nine important families of TFs were extracted from 35 families, and the overall prediction accuracy was 87.4% as evaluated by the jackknife cross-validation test. CONCLUSIONS: Our results are consistent with the notion that TFs are more likely to bind linker DNA sequences than the sequences in the nucleosomes. In addition, our results imply that there may be some TFs that are important for nucleosome positioning but that play an insignificant role in discriminating nucleosome-forming DNA sequences from nucleosome-inhibiting DNA sequences. The hypothesis that TFs play a role in nucleosome positioning is, thus, confirmed by the results of this study.


Assuntos
Montagem e Desmontagem da Cromatina , Nucleossomos/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Fatores de Transcrição/metabolismo , Sítios de Ligação , Nucleossomos/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Fatores de Transcrição/genética
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