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1.
J Adv Res ; 36: 147-161, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35127170

RESUMO

Introduction: Globally, hepatocellular carcinoma (HCC) is the sixth most common malignancy and it has the fourth highest mortality. MicroRNAs play a significant part in biological processes in cell formation and advancement by targeting genes in many cancers including HCC. Objective: In the present study we examine the involvement of miR-4521 and FAM129A correlations in HCC occurrence and progression. Methods: Expression levels of miR-4521 and FAM129A in HCC tissues and cells were detected. Immunohistochemistry was carried out to detect expression of FAM129A, MMP9 and TIMP-1 in HCC tissues. Western blot assays were used to examine expression levels of different genes involve in signaling pathways. Transwell chamber, MTT and wound healing assays were performed to check cell migration, invasion and proliferation rates. Results: Overexpression of FAM129A positively correlated with upregulation of MMP9 and negatively correlated with TIMP-1 in HCC patient samples, which encouraged progression and metastasis of HCC. An antagonistic relation between miR-4521 and FAM129A was detected in current study, down-regulation of miR-4521 and up-regulation of FAM129A was demonstrated in HCC tissues and cell lines as compare to normal tissue samples and the normal cell line LO2. Overexpressing miR-4521 and silencing FAM129A impaired HCC cell migratory and invasive properties and suppressed cell proliferation. Mutually, miR-4521-FAM129A axial regulation inhibited in vitro proliferation of cells by promoting apoptosis through the p-FAK/p-AKT/MDM2/P53 and p-FAK/p-AKT/BCL-2/BAX/Cytochrome-C/Caspase-3/Caspase-9 pathways, respectively, and suppressed the migration and invasion capabilities of HCCLM3 and HepG2 cells via the TIMP-1/MMP9/MMP2 and p-FAK/p-AKT pathway. Conclusion: Our work found the axial regulation mechanism of miR-4521-FAM129A in HCC. Deficiency of miR-4521 and abundance of FAM129A synergistically enhanced cancer progression by increasing cell proliferation and malignant invasion and by inhibiting apoptosis. These discoveries suggest that miR-4521/FAM129A might play a vital role in hepatic cancer progression and could be a candidate for its therapy.


Assuntos
Biomarcadores Tumorais/antagonistas & inibidores , Carcinoma Hepatocelular , Neoplasias Hepáticas , MicroRNAs , Proteínas de Neoplasias/antagonistas & inibidores , Biomarcadores Tumorais/metabolismo , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Invasividade Neoplásica/genética , Proteínas de Neoplasias/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/genética
2.
J Adv Res ; 30: 85-102, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-34026289

RESUMO

Introduction: As a member of annexin family proteins, annexin A3 (ANXA3) has 36-kDa and 33-kDa isoforms. ANXA3 plays crucial roles in the tumorigenesis, aggressiveness and drug-resistance of cancers. However, previous studies mainly focused on the role of total ANXA3 in cancers without distinguishing the distinction between the two isoforms, the role of 33-kDa ANXA3 in cancer remains unclear. Objectives: Current work aimed to investigate the function and regulation mechanism of 33-kDa ANXA3 in hepatocarcinoma. Methods: The expressions of ANXA3, CRKL, Rac1, c-Myc and pAkt were analyzed in hepatocarcinoma specimens by Western blotting. The biological function of 33-kDa ANXA3 in the growth, metastasis, apoptosis, angiogenesis, chemoresistance of hepatocarcinoma cells with the underlying molecular mechanism were investigated using gain-of-function strategy in vitro or in vivo. Results: 33-kDa ANXA3 was remarkably upregulated in tumor tissues compared with corresponding normal liver tissues of hepatocarcinoma patients. Its stable knockdown decreased the in vivo tumor growing velocity and malignancy of hepatocarcinoma HepG2 cells transplanted in nude mice. The in vitro experimental results indicated 33-kDa ANXA3 knockdown suppressed the proliferation, colony forming, migration and invasion abilities of HepG2 cells through downregulating CRKL, Rap1b, Rac1, pMEK, pERK2 and c-Myc in ERK pathway; inhibited angiogenesisability of HepG2 cells through inactivating PI3K/Akt-HIF pathway; induced apoptosis and enhanced chemoresistance of HepG2 cells through increasing Bax/decreasing Bcl-2 expressions and inactivating caspase 9/caspase 3 in intrinsic apoptosis pathway. Accordingly, CRKL, Rac1, c-Myc and pAkt were also upregulated in hepatocarcinoma patients ' tumor tissues compared with corresponding normal liver tissues. Conclusions: The overexpression of 33-kDa ANXA3 is involved in the clinical progression of hepatocarcinoma and in the malignancy, angiogenesis and apoptosis of hepatocarcinoma cells. It is of potential use in hepatocarcinoma diagnosis and treatment.


Assuntos
Anexina A3/metabolismo , Apoptose , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Animais , Carcinogênese/metabolismo , Carcinoma Hepatocelular/patologia , Movimento Celular , Proliferação de Células , Resistencia a Medicamentos Antineoplásicos , Feminino , Células Hep G2 , Humanos , Neoplasias Hepáticas/patologia , Sistema de Sinalização das MAP Quinases , Masculino , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Fosfatidilinositol 3-Quinases/metabolismo , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo
3.
Mol Biol Rep ; 48(4): 3579-3591, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33877528

RESUMO

MicroRNAs (miRNAs) are a class of single-stranded noncoding and endogenous RNA molecules with a length of 18-25 nucleotides. Previous work has shown that miR-124-3p leads to malignant progression of cancer including cell apoptosis, migration, invasion, drug resistance, and also recovers neural function, affects adipogenic differentiation, facilitates wound healing through control of various target genes. miR-124-3p has been mainly previously characterized as a tumor suppressor regulating tumorigenesis and progression in several cancers, such as hepatocellular carcinoma (HCC), gastric cancer (GC), bladder cancer, ovarian cancer (OC), and leukemia, as a tumor promotor in breast cancer (BC), and it has been also widely studied in a variety of neurological diseases, like Parkinson's disease (PD), dementia and Alzheimer's disease (AD), and cardiovascular diseases, ulcerative colitis (UC), acute respiratory distress syndrome (ARDS). To lay the groundwork for future therapeutic strategies, in this review we mainly focus on the most recent years of literature on the functions of miR-124-3p in related major cancers, as well as its downstream target genes. Although current work as yet provides an incomplete picture, miR-124-3p is still worthy of more attention as a practical and effective clinical biomarker.


Assuntos
Carcinogênese/metabolismo , MicroRNAs/metabolismo , Animais , Carcinogênese/genética , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/metabolismo , Humanos , MicroRNAs/genética , Neoplasias/genética , Neoplasias/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo
5.
J Cell Mol Med ; 25(5): 2714-2724, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33523562

RESUMO

Abnormal glucose metabolism may contribute to cancer progression. As a member of the CRK (v-crk sarcoma virus CT10 oncogene homologue) adapter protein family, CRKL (CRK-like) associated with the development and progression of various tumours. However, the exact role and underlying mechanism of CRKL on energy metabolism remain unknown. In this study, we investigated the effect of CRKL on glucose metabolism of hepatocarcinoma cells. CRKL and PI3K were found to be overexpressed in both hepatocarcinoma cells and tissues; meanwhile, CRKL up-regulation was positively correlated with PI3K up-regulation. Functional investigations revealed that CRKL overexpression promoted glucose uptake, lactate production and glycogen synthesis of hepatocarcinoma cells by up-regulating glucose transporters 1 (GLUT1), hexokinase II (HKII) expression and down-regulating glycogen synthase kinase 3ß (GSK3ß) expression. Mechanistically, CRKL promoted glucose metabolism of hepatocarcinoma cells via enhancing the CRKL-PI3K/Akt-GLUT1/HKII-glucose uptake, CRKL-PI3K/Akt-HKII-glucose-lactate production and CRKL-PI3K/Akt-Gsk3ß-glycogen synthesis. We demonstrate CRKL facilitates HCC malignancy via enhancing glucose uptake, lactate production and glycogen synthesis through PI3K/Akt pathway. It provides interesting fundamental clues to CRKL-related carcinogenesis through glucose metabolism and offers novel therapeutic strategies for hepatocarcinoma.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Carcinoma Hepatocelular/etiologia , Carcinoma Hepatocelular/metabolismo , Glucose/metabolismo , Neoplasias Hepáticas/etiologia , Neoplasias Hepáticas/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Suscetibilidade a Doenças , Regulação Neoplásica da Expressão Gênica , Glicogênio/biossíntese , Humanos , Neoplasias Hepáticas/patologia , Proteômica/métodos , Transdução de Sinais
6.
J Exp Clin Cancer Res ; 39(1): 70, 2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32326970

RESUMO

BACKGROUND: Tumor metastasis is one of the main causes of the high mortality of hepatocellular carcinoma (HCC). E-Twenty Six variant gene 6 (ETV6) is a strong transcriptional repressor, associated with the development and progression of tumors. However, the exact role and underlying mechanism of ETV6 in HCC remain unclear. METHODS: Western blotting, quantitative real-time PCR and immunohistochemistry were used to detect the expression levels of ETV6, CRKL (v-crk sarcoma virus CT10 oncogene homologue (avian)-like) and miR-429 in HCC tissues and cells; Transwell chamber and F-actin cytoskeleton staining assay to examine the effects of ETV6 and CRKL deregulation on the migration, invasion and cytoskeleton of HCC cells; Co-immunoprecipitation assay to determine the interaction between CRKL and ETV6; Chromatin immunoprecipitation assay to investigate the interaction between ETV6 and miR-429. RESULTS: We established a novel ETV6-miR-429-CRKL regulatory circuitry contributes to HCC metastasis. ETV6 and CRKL were frequently increased, while miR-429 was downregulated in both hepatocarcinoma tissues and hepatocarcinoma cells. Moreover, ETV6 upregulation was positively correlated with CRKL upregulation, and two negative correlations were also established for ETV6 and CRKL upregulation with miR-429 downregulation in both hepatocarcinoma patients' tumorous tissues and hepatocarcinoma cells. Functional investigations revealed that overexpression and knockdown of ETV6 was remarkably effective in promoting and suppressing HCC cell migration, invasion, cytoskeleton F-actin expression and arrangement, whereas, CRKL overexpression exhibited similar effects to the overexpression of ETV6. Mechanistically, ETV6 negatively regulates miR-429 expression by directly binding to the promoter region of miR-429; miR-429 negatively regulates CRKL expression by selectively targeting CRKL-3'-UTR; ETV6 directly binds to CRKL and positively regulates its expression, which in turn CRKL positively regulates ETV6 expression. CONCLUSIONS: Our data demonstrated that ETV6 promotes migration and invasion of HCC cells by directly binding to promoter region of miR-429 via modulating CRKL expression. The newly identified ETV6-miR-429-CRKL regulatory circuitry contributes to the aggressiveness of HCC, which provides new clues for fundamental research on diagnosis and treatment parameters for HCC.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , MicroRNAs/genética , Proteínas Proto-Oncogênicas c-ets/genética , Proteínas Repressoras/genética , Proteínas Adaptadoras de Transdução de Sinal/biossíntese , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Feminino , Regulação Neoplásica da Expressão Gênica , Células Hep G2 , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , MicroRNAs/biossíntese , Pessoa de Meia-Idade , Proteínas Proto-Oncogênicas c-ets/biossíntese , Proteínas Repressoras/biossíntese , Transfecção , Variante 6 da Proteína do Fator de Translocação ETS
7.
Acta Crystallogr E Crystallogr Commun ; 73(Pt 4): 620-622, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28435734

RESUMO

The MnII ion in the structure of the mononuclear title compound, [Mn(C4H3N2O2)2(H2O)4], is situated on an inversion center and is coordinated by two O atoms from two deprotonated 4,6-di-hydroxy-pyrimidine ligands and by four O atoms from water mol-ecules giving rise to a slightly distorted octa-hedral coordination sphere. The complex includes an intra-molecular hydrogen bond between an aqua ligand and the non-protonated N ring atom. The extended structure is stabilized by inter-molecular hydrogen bonds between aqua ligands, by hydrogen bonds between N and O atoms of the ligands of adjacent mol-ecules, and by hydrogen bonds between aqua ligands and the non-coordinating O atom of an adjacent mol-ecule.

8.
J Enzyme Inhib Med Chem ; 32(1): 496-503, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28110559

RESUMO

Lysyl oxidase has emerged as an important enzyme in cancer metastasis. Its activity has been reported to become upregulated in several types of cancer, and blocking its activity has been shown to limit the metastatic potential of various cancers. The small-molecules phenylhydrazine and ß-aminopropionitrile are known to inhibit lysyl oxidase; however, issues of stability, toxicity, and poorly defined mechanisms limit their potential use in medical applications. The experiments presented herein evaluate three other families of hydrazine-derived compounds - hydrazides, alkyl hydrazines, and semicarbazides - as irreversible inhibitors of lysyl oxidase including determining the kinetic parameters and comparing the inhibition selectivities for lysyl oxidase against the topaquinone-containing diamine oxidase from lentil seedlings. The results suggest that the hydrazide group may be a useful core functionality that can be developed into potent and selective inhibitors of lysyl oxidase and eventually find application in cancer metastasis research.


Assuntos
Hidrazinas/química , Oxirredutases/química , Quinonas/química
9.
Oncol Lett ; 10(4): 1947-1952, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26622779

RESUMO

Annexin A6 (AnxA6) is a member of a conserved superfamily of Ca2+-dependent membrane-binding annexin proteins. It participates in membrane and cytoskeleton organization, cholesterol homeostasis, membrane trafficking, cell adhesion and signal transduction. The expression levels of AnxA6 are closely associated with melanoma, cervical cancer, epithelial carcinoma, breast cancer, gastric cancer, prostate cancer, acute lymphoblastic leukemia, chronic myeloid leukemia, large-cell lymphoma and myeloma. AnxA6 exhibits dual functions in cancer, acting either as a tumor suppressor or promoter, depending on the type of cancer and the degree of malignancy. In several types of cancer, AnxA6 acts via Ras, Ras/MAPK and/or FAK/PI3K signaling pathways by mainly mediating PKCα, p120GAP, Bcr-Abl and YY1. In the present review, the roles of AnxA6 in different types of cancer are summarized.

10.
Clin Chim Acta ; 431: 164-8, 2014 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-24508622

RESUMO

Ubiquitously expressed in many cell types, annexin A11 (Anxa11) is a member of the multigene family of Ca(2+)-regulated phospholipid-dependent and membrane-binding annexin proteins. Studies have shown that Anxa11 plays an important role in cell division, Ca(2+) signaling, vesicle trafficking and apoptosis. The deregulation and mutation of Anxa11 are involved in systemic autoimmune diseases, sarcoidosis and the development, chemoresistance and recurrence of cancers. Malfunction of Anxa11 may lead to or enhance the metastasis, invasion and drug resistance of cancers through the platelet-derived growth factor receptor (PDGFR) pathway and/or the mitogen-activated protein kinase (MAPK)/p53 pathway. In a variety of diseases, Anxa11 is most commonly reported to function through interactions with apoptosis-linked gene-2 protein (ALG-2) and/or calcyclin (S100A6). Although it has been little studied, Anxa11 is a promising biomarker for the diagnosis, treatment and prognosis of certain diseases. In this review, the associations of Anxa11 with Ca(2+)-regulated exocytosis, cytokinesis, sex differentiation, autoimmune diseases, thrombolysis and cancers are summarized and interpreted.


Assuntos
Anexinas/metabolismo , Animais , Anexinas/química , Anexinas/fisiologia , Citocinese/fisiologia , Doença , Exocitose/fisiologia , Humanos , Neoplasias/metabolismo
11.
Clin Chim Acta ; 417: 39-44, 2013 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-23266771

RESUMO

Beta-actin (ACTB) has traditionally been regarded as an endogenous housekeeping gene and has been widely used as a reference gene/protein in quantifying expression levels in tumors. However, ACTB is closely associated with a variety of cancers and accumulating evidence indicates that ACTB is de-regulated in liver, melanoma, renal, colorectal, gastric, pancreatic, esophageal, lung, breast, prostate, ovarian cancers, leukemia and lymphoma. ACTB is generally found to be up-regulated in the majority of tumor cells and tissues. The abnormal expression and polymerization of ACTB and the resulting changes to the cytoskeleton are revealed to be associated with the invasiveness and metastasis of cancers. The current review explores relevant mechanisms, integrates current understandings, and provides suggestions for future studies of the roles of ACTB in tumors.


Assuntos
Actinas , Neoplasias , Actinas/genética , Actinas/metabolismo , Resistencia a Medicamentos Antineoplásicos , Regulação Neoplásica da Expressão Gênica , Humanos , Metástase Neoplásica , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia
12.
J Neural Transm (Vienna) ; 118(7): 1111-4, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21188434

RESUMO

Proteolytic digestion of bovine aortic lysyl oxidase followed by tandem mass spectrometry has enabled assignment of all five disulfide bonds. The results indicate that the enzyme has a very stable central core containing three disulfide bonds, the lysyl tyrosyl quinone cross-link and the copper. This core is well isolated from solvent with the result that the oxidized (normal) form of the enzyme is remarkably resistant to proteolysis and is unusually stable at high temperatures and in the presence of denaturants.


Assuntos
Dissulfetos/química , Estabilidade Proteica , Proteína-Lisina 6-Oxidase/química , Proteína-Lisina 6-Oxidase/fisiologia , Sequência de Aminoácidos , Animais , Domínio Catalítico/fisiologia , Bovinos , Cobre/química , Cisteína/química , Temperatura Alta , Oxirredução
13.
J Neural Transm (Vienna) ; 118(7): 1101-9, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21190048

RESUMO

In order to identify the ligands coordinating with copper in lysyl oxidase, the enzyme was expressed in an E. coli expression system and active enzyme obtained after refolding in the presence of Cu(II). The five histidines found in the putative copper-binding region were sequentially mutated to alanines and the enzymatic activities of the resultant mutants were monitored, together with the copper content, the CD and fluorescence spectra, and the redox-cycling activity. The spectroscopic results show that in all cases the protein folded correctly but that the copper-content, enzymatic activity, and redox-cycling ability depended on the mutation. One mutant was fully functional, and two others completely lacked copper, the lysyl tyrosyl quinone (LTQ) cofactor, and activity. A fourth incorporated copper but lacked LTQ and enzymatic activity. The remaining mutant incorporated copper and had redox-cycling activity but no enzymatic activity. The results suggest that three of the five histidines in the putative copper-binding domain, H292, H294, H296, are the copper ligands and essential to the formation of LTQ. A fourth, H289, is not involved in LTQ formation or activity, while a fifth, H303, is suggested to be a general base in the catalytic mechanism.


Assuntos
Cobre/química , Cobre/metabolismo , Proteína-Lisina 6-Oxidase/química , Proteína-Lisina 6-Oxidase/metabolismo , Sequência de Aminoácidos , Domínio Catalítico/genética , Linhagem Celular , Ativação Enzimática/genética , Histidina/química , Humanos , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Ligantes , Mutagênese Sítio-Dirigida/métodos , Oxirredução/efeitos dos fármacos , Ligação Proteica/fisiologia , Dobramento de Proteína/efeitos dos fármacos , Estrutura Terciária de Proteína/genética , Proteína-Lisina 6-Oxidase/genética
14.
Protein Expr Purif ; 74(1): 116-21, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20600936

RESUMO

Lysyl oxidase is a highly insoluble enzyme requiring high concentrations of urea to solubilize. A method to obtain lysyl oxidase in high yields directly from an Escherichia coli culture without the need for refolding of inclusion bodies has been developed using nutrient rich media. pET21b was used to overexpress the lysyl oxidase enzyme and to introduce a C-terminal 6X histidine tag for purification. Lysyl oxidase yields of 10 mg of active and properly folded enzyme per liter of media have been obtained. Purification was achieved via affinity chromatography using a Ni-NTA column. Copper content was found to be 19%. LTQ cofactor formation in LOX is a self-processing event in the presence of copper. LTQ content was determined to be 24% based on reaction with phenylhydrazine to form a phenylhydrazone adduct. Quantification of this adduct was attained using the previously reported extinction coefficient of 15.4 mM(-1)cm(-1). LTQ presence was also verified by redox cycling. Specific enzymatic activity was measured to be 0.31 U/mg, one of the highest activities reported.


Assuntos
Escherichia coli/genética , Proteína-Lisina 6-Oxidase/genética , Proteína-Lisina 6-Oxidase/isolamento & purificação , Sequência de Aminoácidos , Cobre/metabolismo , Expressão Gênica , Humanos , Dados de Sequência Molecular , Oxirredução , Fenil-Hidrazinas/antagonistas & inibidores , Proteína-Lisina 6-Oxidase/metabolismo , Quinonas/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência
15.
Bioinorg Chem Appl ; 2010: 724210, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20300581

RESUMO

The utility of the extensible systematic force field (ESFF) was tested for copper(II) binding to a 34-amino-acid Cu(II) peptide, which includes five histidine residues and is the putative copper-binding site of lysyl oxidase. To improve computational efficiency, distance geometry calculations were used to constrain all combinations of three histidine ligands to be within bonding distance of the copper and the best results were utilized as starting structures for the ESFF computations. All likely copper geometries were modeled, but the results showed only a small dependence on the geometrical model in that all resulted in a distorted square pyramidal geometry about the copper, some of the imidazole rings were poorly oriented for ligation to the Cu(II), and the copper-nitrogen bond distances were too long. The results suggest that ESFF should be used with caution for Cu(II) complexes where the copper-ligand bonds have significant covalency and when the ligands are not geometrically constrained to be planar.

16.
Biochimie ; 92(7): 901-8, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20211680

RESUMO

The oncogenic potential of the high-risk human papillomavirus (HPV) relies on the expression of genes specifying the E7 and E6 proteins. To investigate further the variation in oligomeric structure that has been reported for different E7 proteins, an HPV-18 E7 cloned from a Hispanic woman with cervical intraepithelial neoplasia was purified to homogeneity most probably as a stable monomeric protein in aqueous solution. We determined that one zinc ion is present per HPV-18 E7 monomer by amino acid and inductively coupled plasma-atomic emission spectroscopy analysis. Intrinsic fluorescence and circular dichroism spectroscopic results indicate that the zinc ion is important for the correct folding and thermal stability of HPV-18 E7. Hydroxyl radical mediated protein footprinting coupled to mass spectrometry and other biochemical and biophysical data indicate that near the C-terminus, the four cysteines of the two Cys-X(2)-Cys motifs that are coordinated to the zinc ion form a solvent inaccessible core. The N-terminal LXCXE pRb binding motif region is hydroxyl radical accessible and conformationally flexible. Both factors, the relative flexibility of the pRb binding motif at the N-terminus and the C-terminal metal-binding hydrophobic solvent-protected core, combine together and facilitate the biological functions of HPV-18 E7.


Assuntos
Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Papillomavirus Humano 18 , Interações Hidrofóbicas e Hidrofílicas , Proteínas Oncogênicas Virais/química , Proteínas Oncogênicas Virais/metabolismo , Solventes/química , Motivos de Aminoácidos , Sequência de Aminoácidos , Proteínas de Ligação a DNA/isolamento & purificação , Feminino , Humanos , Radical Hidroxila/metabolismo , Dados de Sequência Molecular , Proteínas Oncogênicas Virais/isolamento & purificação , Dobramento de Proteína , Multimerização Proteica , Estabilidade Proteica , Estrutura Quaternária de Proteína , Proteômica , Relação Estrutura-Atividade , Temperatura , Água/química , Zinco/metabolismo
17.
Biochimie ; 92(4): 343-9, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20100538

RESUMO

An L-amino acid oxidase (Akbu-LAAO) was isolated from the venom of Agkistrodon blomhoffii ussurensis snake using DEAE Sephadex A-50 ion-exchange, Sephadex G-75 gel filtration, and high performance liquid chromatographies. The homogeneity and molecular mass of Akbu-LAAO were analyzed by SDS-PAGE and MALDI-TOF spectrometry. The sequences of ten peptides from Akbu-LAAO were established by HPLC-nESI-MS/MS analysis. Protein sequence alignment indicated that i) that Akbu-LAAO is a new snake venom LAAO, and ii) Akbu-LAAO shares homology with several LAAOs from the venoms of Calloselasma rhodost, Agkistrodon halys, Daboia russellii siamensis, and Trimeresurus stejnegeri. Akbu-LAAO is a homodimer with a molecular mass of approximately 124.4 kDa. It reacts optimally with its enzymatic substrate, Leu, at pH 4.7 with a K(m) of 2.1 mM. ICP-AES measurements showed that Akbu-LAAO contains four Zn(2+) per dimer that are unessential for the hydrolytic activity of the enzyme. The emission fluorescence intensity of Akbu-LAAO decreases by 61% on removal of Zn(2+) indicating that the zinc probably helps maintain the structural integrity of the enzyme. The addition of exogenous metal ions, including Mg(2+), Mn(2+), Ca(2+), Ce(3+), Nd(3+), Co(2+) and Tb(3+), increases the l-Leu hydrolytic activity of the enzyme. Akbu-LAAO shows apparent anti-aggregation effects on human and rabbit platelets. It exhibits a strong bacteriostasis effect on Staphylococcus aureus, eighteen fold that of cephalosporin C under the same conditions. Taken together, the biochemical, proteomic, structural and functional characterizations reveal that Akbu-LAAO is a novel LAAO with promise for biotechnological and medical applications.


Assuntos
Venenos de Crotalídeos/enzimologia , L-Aminoácido Oxidase/isolamento & purificação , Agkistrodon , Sequência de Aminoácidos , Animais , Eletroforese em Gel de Poliacrilamida , Humanos , L-Aminoácido Oxidase/metabolismo , Metais/farmacologia , Dados de Sequência Molecular , Agregação Plaquetária/efeitos dos fármacos , Multimerização Proteica , Coelhos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrofotometria Atômica , Staphylococcus aureus/efeitos dos fármacos , Zinco/química
18.
Biochimie ; 91(4): 558-67, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19278623

RESUMO

A phospholipase A(2) was isolated from the snake venom of Chinese Agkistrodon blomhoffii Ussurensis by column chromatography using DEAE Sephadex A-50 ion-exchange chromatography, Sephadex G-75 gel filtration chromatography and Mono Q ion-exchange chromatography, and designated as Akbu-PLA(2). It showed an average molecular mass of 13,980+/-3 amu determined by MALDI TOF mass spectrometry. Protein identification results from HPLC-nESI-MS/MS analysis indicated that the Akbu-PLA(2) was a new snake venom acidic PLA(2). Seven peptides were sequenced from Akbu-PLA(2) by HPLC-nESI-MS/MS analysis. Sequencing alignment indicated that Akbu-PLA(2) shared homolog peptides of phospholipases A(2) from the venoms of Gloydius ussurensis, Gloydius halys, Gloydius halys (halys viper), Deinagkistrodon acutus and Agkistrodon halys Pallas. Akbu-PLA(2) has an optimum hydrolytic activity temperature of approximately 45 degrees C. The intrinsic fluorescences of Tyr and Trp residues of Akbu-PLA(2) showed emission wavelengths red-shifted by 13.6 and 1.6 nm from those of free Tyr and Trp, respectively. Akbu-PLA(2) was shown to contain one Ca(2+) per monomer by ICP-AES measurement. The Ca(2+) ion was found to be critical for both the hydrolytic activity and the structure of Akbu-PLA(2). Ca(2+) increased the emission fluorescence intensity and the hydrophobicity of the environment of Akbu-PLA(2). The hydrolytic activity of Akbu-PLA(2) was accelerated due to the addition of Ca(2+) ion by enhancing the substrate binding. However, a protein component with the molecular weight two-fold relative to that of Akbu-PLA(2) was found to be difficult to eliminate for the purification of Akbu-PLA(2). HPLC-nESI-MS/MS detected the same peptides from it as from Abku-PLA(2), which indicated that it should be a homodimer of Akbu-PLA(2). A proteomic approach, 2D SDS-PAGE coupled to HPLC-nESI-MS/MS, supported the co-existence of the Akbu-PLA(2) monomer and dimer in the crude snake venom. Results from the combination of phosphoprotein and glycoprotein specific stains combined with the HPLC-nESI-MS/MS method indicated that both the Akbu-PLA(2) monomer and dimer were both phosphorylated and glycosylated. The addition of exogenous Ca(2+) ion was found to be able to promote the dimer formation of Akbu-PLA(2). We conclude that a novel PLA(2) was successfully obtained. The systemically biochemical, proteomic, structural and functional characterization results from Akbu-PLA(2) reveal new threads and provide valuable inputs for the study of snake venom phospholipases A(2).


Assuntos
Venenos de Crotalídeos/enzimologia , Fosfolipases A2/química , Fosfolipases A2/classificação , Sequência de Aminoácidos , Animais , Sequência de Bases , Cálcio/metabolismo , Dimerização , Hidrólise , Dados de Sequência Molecular , Fosfolipases A2/isolamento & purificação , Filogenia , Proteômica , Alinhamento de Sequência
19.
Rapid Commun Mass Spectrom ; 22(20): 3172-8, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18798201

RESUMO

The potential biomarkers for the lymphatic metastatic process of mouse hepatocarcinoma were investigated by using two-dimensional difference in-gel electrophoresis (2D DIGE), high-performance liquid chromatography/nano-electrospray ionization tandem mass spectrometry (HPLC/nESI-MS/MS) and GeneChip. 2D DIGE was performed to screen and quantify the differentially expressed proteins between two well-established mouse hepatocarcinoma cell lines, Hca-F with 75% and Hca-P with 25% metastasis rate of lymph node potentials. The protein spots in the gel were visualized by the highly sensitive Deep Purple (GE Healthcare) fluorescent stain. Protein identification was obtained for gel spots by HPLC/nESI-MS/MS analysis with high quality. GeneChip microarray was performed to identify genes differentially expressed at the mRNA level. Seventeen genes including the chloride intracellular channel l, caspase 3, fructose bisphosphatase 2, glutamate dehydrogenase 1, V-crk sarcoma virus CT10 oncogene homolog, N-myc downstream regulated gene1, villin2, gelsolin, enoyl coenzyme A hydratase 1, transketolase, vimentin, annexins A5 and A7, keratin complex2 basic gene7 and gene8, lactamase (bata 2) and Ero1-like protein were found abnormally regulated and expressed concordantly both at the protein and mRNA levels between the two cell lines. More than half of these genes were for the first time revealed to be involved directly in hepatocarcinoma due to the lymphatic metastasis. The interdisciplinary combination of HPLC/nESI-MS/MS with 2D DIGE and GeneChip techniques opens up the possibility for the biomarker discovery of disease with high confidence.


Assuntos
Biomarcadores Tumorais/análise , Metástase Linfática/diagnóstico , Metástase Linfática/genética , Animais , Western Blotting , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , Eletroforese em Gel Bidimensional , Hidrólise , Processamento de Imagem Assistida por Computador , Indicadores e Reagentes , Camundongos , Camundongos Endogâmicos , Proteínas de Neoplasias/análise , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/análise , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , RNA Neoplásico/análise , RNA Neoplásico/biossíntese , RNA Neoplásico/genética , Espectrometria de Fluorescência , Espectrometria de Massas em Tandem , Tripsina
20.
Toxicon ; 52(7): 760-8, 2008 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-18817802

RESUMO

A novel serine protease, ABUSV-SPase, was isolated to homogeneity for the first time from Chinese Agkistrodon blomhoffii ussurensis snake venom, and its enzymatic and structural properties were characterized by multiple techniques. ABUSV-SPase is a stable monomeric protein with a molecular mass of 26,752.6a.m.u. It reacts optimally with its substrate Nalpha-tosyl-l-arginine methyl ester (TAME) at pH 7.0 and 41 degrees C. ESI-MS/MS analysis indicates that ABUSV-SPase is a new serine protease, sharing peptide homologies with various snake venom serine proteases, especially the snake venom thrombin-like enzymes of this group, and serine protease precursors. It is a zinc-containing protein, and although zinc is not essential for activity, its replacement by various divalent metal ions, including Mg2+, Mn2+, and Ca2+, increases the TAME hydrolysis activity of the enzyme. The intrinsic fluorescences of Tyr and Trp residues of ABUSV-SPase have emission wavelengths red-shifted by 12.8nm and 3.6nm from those of free Tyr and Trp, respectively. The zinc ion increases the hydrophobicity of the environment of the Trp residues, increases the thermostability of the protein, and affects the protein secondary structure to stabilize the enzyme, but appears to have no direct role in its esterase hydrolysis activity.


Assuntos
Agkistrodon , Venenos de Crotalídeos/enzimologia , Serina Endopeptidases/química , Sequência de Aminoácidos , Animais , Estabilidade Enzimática , Fluorescência , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Filogenia , Estrutura Quaternária de Proteína , Alinhamento de Sequência , Serina Endopeptidases/isolamento & purificação , Serina Endopeptidases/fisiologia , Espectrometria de Massas por Ionização por Electrospray , Temperatura , Zinco/química
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