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1.
Toxicol Appl Pharmacol ; 449: 116139, 2022 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-35750203

RESUMO

Biomacromolecules such as proteins and nucleic acids are very attractive due to their high efficiency and specificity as cancer therapeutics. In fact, the endocytosed macromolecules are often trapped in the endosomes and cannot exhibit pharmacological effects well. Many strategies have been used to address this bottleneck, and one promising approach is to exploit the endosomal escape-promoting effect of triterpenoid saponins to aid in the release of biomacromolecules. Here, Raddeanin A (RA, an oleanane-type triterpenoid saponin) was proved to significantly promote endosomal escape as it recruited Galectin-9, an endosomal escape event reporter. As expected, RA effectively enhanced the anti-tumor effect of MAP30 (a type I ribosome-inactivating protein derived from Momordica charantia). However, based on the results of fluorescent colocalization, RA did not significantly promote MAP30 release from endosomes, suggesting that RA enhances MAP30 activity not only by promoting endosomal escape. Furthermore, it was found that the inhibitors of micropinocytosis and caveolae could almost completely inhibit the cytotoxicity of MAP30 combined with RA without affecting the cytotoxicity of MAP30 alone, indicating that RA may regulate the endocytic pathway of MAP30. Meanwhile, the effect of RA is related to the intra vesicular pH and cholesterol content on cell membrane, and is also cell-type dependent. Therefore, RA enhanced the anti-tumor effect of MAP30 in multiple ways, not just by promoting endosomal escape. Our findings will help to further decipher the possible mechanisms by which triterpenoid saponins enhance drug activity, and provide a new perspective for improving the activity of endocytosed drugs.


Assuntos
Neoplasias , Saponinas , Triterpenos , Endossomos/metabolismo , Humanos , Neoplasias/metabolismo , Proteínas Inativadoras de Ribossomos Tipo 2/química , Proteínas Inativadoras de Ribossomos Tipo 2/farmacologia , Saponinas/farmacologia , Triterpenos/farmacologia
2.
Toxins (Basel) ; 13(12)2021 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-34941700

RESUMO

Kirkiin is a new type 2 ribosome-inactivating protein (RIP) purified from the caudex of Adenia kirkii with a cytotoxicity compared to that of stenodactylin. The high toxicity of RIPs from Adenia genus plants makes them interesting tools for biotechnology and therapeutic applications, particularly in cancer therapy. The complete amino acid sequence and 3D structure prediction of kirkiin are here reported. Gene sequence analysis revealed that kirkiin is encoded by a 1572 bp open reading frame, corresponding to 524 amino acid residues, without introns. The amino acid sequence analysis showed a high degree of identity with other Adenia RIPs. The 3D structure of kirkiin preserves the overall folding of type 2 RIPs. The key amino acids of the active site, described for ricin and other RIPs, are also conserved in the kirkiin A chain. Sugar affinity studies and docking experiments revealed that both the 1α and 2γ sites of the kirkiin B chain exhibit binding activity toward lactose and D-galactose, being lower than ricin. The replacement of His246 in the kirkiin 2γ site instead of Tyr248 in ricin causes a different structure arrangement that could explain the lower sugar affinity of kirkiin with respect to ricin.


Assuntos
Sequência de Aminoácidos , Sítios de Ligação , Proteínas Inativadoras de Ribossomos Tipo 2/química , Proteínas Inativadoras de Ribossomos Tipo 2/genética , Domínio Catalítico , Simulação de Acoplamento Molecular , Passifloraceae/química , Passifloraceae/genética , Proteínas de Plantas/química , Domínios Proteicos , Ricina/química , Análise de Sequência de DNA
3.
Int J Mol Sci ; 22(15)2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34361050

RESUMO

Sialic acid (Sia) is considered as one of the most important biomolecules of life since its derivatives and terminal orientations on cell membranes and macromolecules play a major role in many biological and pathological processes. To date, there is only a limited number of active molecules that can selectively bind to Sia and this limitation has made the study of this glycan challenging. The lectin superfamily is a well-known family of glycan binding proteins, which encompasses many strong glycan binding peptides with diverse glycan affinities. Mistletoe lectin (ML) is considered one of the most active members of lectin family which was initially classified in early studies as a galactose binding lectin; more recent studies have suggested that the peptide can also actively bind to Sia. However, the details with respect to Sia binding of ML and the domain responsible for this binding are left unanswered because no comprehensive studies have been instigated. In this study, we sought to identify the binding domain responsible for the sialic acid affinity of mistletoe lectin isoform I (MLI) in comparison to the binding activity of elderberry lectin isoform I (SNA), which has long been identified as a potent Sia binding lectin. In order to execute this, we performed computational carbohydrate-protein docking for MLB and SNA with Neu5Ac and ß-Galactose. We further analyzed the coding sequence of both lectins and identified their glycan binding domains, which were later cloned upstream and downstream to green fluorescent protein (GFP) and expressed in Escherichia coli (E. coli). Finally, the glycan affinity of the expressed fusion proteins was assessed by using different biochemical and cell-based assays and the Sia binding domains were identified.


Assuntos
Ácido N-Acetilneuramínico/metabolismo , Proteínas Inativadoras de Ribossomos Tipo 2/química , Toxinas Biológicas/química , Sítios de Ligação , Linhagem Celular Tumoral , Humanos , Simulação de Acoplamento Molecular , Ácido N-Acetilneuramínico/química , Ligação Proteica , Proteínas Inativadoras de Ribossomos Tipo 2/metabolismo , Toxinas Biológicas/metabolismo
4.
Molecules ; 25(11)2020 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-32486427

RESUMO

Mistletoe (Viscum album) extracts have been used as alternative and complementary therapeutic preparations in multiple cancers for decades. Mistletoe lectins (ML-I, ML-II, and ML-III) are considered to be the main anticancer components of such preparations. In the present study, ML-II was transiently expressed in Nicotiana benthamiana using the pEAQ-HT expression system. Expression levels of up to 60 mg/kg of the infiltrated plant tissue were obtained, and a three-fold increase was achieved by adding the endoplasmic reticulum (ER) retention signal KDEL to the native ML-II sequence. The native protein containing His-tag and KDEL was purified by immobilized metal affinity chromatography (IMAC) and gel filtration. We found that the recombinant ML-II lectin was glycosylated and retained its carbohydrate-binding activity. In addition, we demonstrated that plant produced ML-II displayed anticancer activity in vitro, inhibiting non-small cell lung cancer H460 and A549 cells with EC50 values of 4 and 3.5 µg/mL, respectively. Annexin V-448A and PI double staining revealed that cell cytotoxicity occurred via apoptosis induction. These results indicate that ML-II transiently expressed in N. benthamiana plants is a promising candidate as an anticancer agent, although further optimization of production and purification methods is required to enable further in vitro testing, as well as in vivo assays.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Erva-de-Passarinho/química , Nicotiana/química , Proteínas Inativadoras de Ribossomos Tipo 2/química , Toxinas Biológicas/química , Células A549 , Apoptose , Carboidratos/química , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Linhagem Celular Tumoral , Sobrevivência Celular , Cromatografia em Gel , Clonagem Molecular , Ensaios de Seleção de Medicamentos Antitumorais , Retículo Endoplasmático/metabolismo , Endotoxinas/metabolismo , Humanos , Lectinas/química , Neoplasias Pulmonares/tratamento farmacológico , Plantas Geneticamente Modificadas/química , Nicotiana/genética
5.
Sci Rep ; 9(1): 413, 2019 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-30674891

RESUMO

How is a water-soluble globular protein able to spontaneously cross a cellular membrane? It is commonly accepted that it undergoes significant structural rearrangements on the lipid-water interface, thus acquiring membrane binding and penetration ability. In this study molecular dynamics (MD) simulations have been used to explore large-scale conformational changes of the globular viscumin A chain in a complex environment - comprising urea and chloroform/methanol (CHCl3/MeOH) mixture. Being well-packed in aqueous solution, viscumin A undergoes global structural rearrangements in both organic media. In urea, the protein is "swelling" and gradually loses its long-distance contacts, thus resembling the "molten globule" state. In CHCl3/MeOH, viscumin A is in effect turned "inside out". This is accompanied with strengthening of the secondary structure and surface exposure of hydrophobic epitopes originally buried inside the globule. Resulting solvent-adapted models were further subjected to Monte Carlo simulations with an implicit hydrophobic slab membrane. In contrast to only a few point surface contacts in water and two short regions with weak protein-lipid interactions in urea, MD-derived structures in CHCl3/MeOH reveal multiple determinants of membrane interaction. Consequently it is now possible to propose a specific pathway for the structural adaptation of viscumin A with respect to the cell membrane - a probable first step of its translocation into cytoplasmic targets.


Assuntos
Membrana Celular/química , Membranas Artificiais , Redobramento de Proteína , Proteínas Inativadoras de Ribossomos Tipo 2/química , Toxinas Biológicas/química , Transporte Proteico
6.
Eur J Pharm Biopharm ; 132: 211-221, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30223028

RESUMO

Lysolipid-containing thermosensitive liposomes (LTSL) are clinically-relevant drug nanocarriers which have been used to deliver small molecule cytostatics to tumors in combination with local hyperthermia (42 °C) to trigger local drug release. The objective of this study was to investigate the feasibility of LTSL for encapsulation and triggered release of macromolecular drugs such as plant-derived cytotoxins. As therapeutic protein we used Mistletoe lectin-1 (ML1) - a ribosome-inactivating protein with potent cytotoxic activity in tumor cells. Model macromolecules (dextrans, albumin) and ML1 were encapsulated in small unilamellar LTSL with varying lipid compositions by the thin film hydration method and extrusion. LTSLs showed molecular weight dependent heat-triggered release of the loaded cargo. The most promising composition, ML1 formulated in LTSL composed of 86:10:4 %mol DPPC:MSPC:DSPE-PEG2000, was further studied for bioactivity against murine CT26 colon carcinoma cells. Confocal live-cell imaging showed uptake of released ML1 after mild hyperthermia at 42 °C, subsequently leading to potent cytotoxicity by LTSL-ML1. Our study shows that LTSL in combination with localized hyperthermia hold promise as local tumor delivery strategy for macromolecular cytotoxins.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Neoplasias do Colo/tratamento farmacológico , Lipídeos/química , Proteínas Inativadoras de Ribossomos Tipo 2/administração & dosagem , Toxinas Biológicas/administração & dosagem , Albuminas/química , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Linhagem Celular Tumoral , Química Farmacêutica/métodos , Neoplasias do Colo/patologia , Dextranos/química , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Temperatura Alta , Lipossomos , Camundongos , Peso Molecular , Proteínas Inativadoras de Ribossomos Tipo 2/química , Proteínas Inativadoras de Ribossomos Tipo 2/farmacologia , Temperatura , Toxinas Biológicas/química , Toxinas Biológicas/farmacologia
7.
Anticancer Drugs ; 29(8): 736-747, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29912010

RESUMO

Cyclosporin A (CsA) is a calcium antagonist and can enhance the efficacy of some protein drugs, but its mechanism remains unknown. In this study, MAP30, a ribosome-inactivating protein reported to have apoptotic effects on cancer cells, was fused with S3, an epidermal growth factor receptor (EGFR)-targeting peptide. In addition, CsA was used to investigate whether it can further promote the apoptotic effects of S3 fused MAP30 (MAP30-S3). Our result showed that the internalization of FITC-labeled MAP30-S3 was increased significantly by S3 in HeLa cells. Unexpectedly, MAP30-S3 only showed a minor decrease in the viability of EGFR-overexpressing cancer cells, including HeLa, SMMC-7721, and MGC803 (IC50>5 µmol/l). However, 2 µmol/l CsA significantly increased the cytotoxicity of MAP30-S3, especially for HeLa cells (IC50=40.3 nmol/l). In comparison, CsA did not further decrease the cytotoxicity of MAP30-S3 on MRC-5, an EGFR low-expressing cell line from normal lung tissue, indicating that CsA did not affect the cancer-targeting specificity of MAP30-S3. Our results also showed that CsA further increased the apoptotic activity of MAP30-S3 in HeLa cells. CsA could promote the endosomal escape of FITC-MAP30-S3 with a diffused pattern in the cytoplasm. Five endocytic inhibitors were used to investigate the cellular uptake mechanism of MAP30-S3, and the results showed that the endosomal escape-enhancing effect of CsA on MAP30-S3 may be associated with the clathrin-dependent endocytic pathways. Our study suggested that CsA could be a novel endosomal escape enhancer to potentiate the intracellular release of anticancer protein drugs, resulting in their improved therapeutic efficacy.


Assuntos
Ciclosporina/farmacologia , Endossomos/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Proteínas Recombinantes de Fusão/farmacologia , Proteínas Ribossômicas/farmacologia , Proteínas Inativadoras de Ribossomos Tipo 2/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sinergismo Farmacológico , Células HeLa , Humanos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Ribossômicas/química , Proteínas Ribossômicas/genética , Proteínas Inativadoras de Ribossomos Tipo 2/química , Proteínas Inativadoras de Ribossomos Tipo 2/genética
8.
Med Chem ; 14(8): 754-763, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29792147

RESUMO

BACKGROUND: Viscum album (the European mistletoe) is a semi-parasitic plant, which is of high medical interest. It is widely found in Europe, Asia, and North America. It contains at least three distinct lectins (i.e. ML-I, II, and III), varying in molecular mass and specificity. Among them, ML-I is in focus of medical research for various activities, including anti-cancer activities. To understand the molecular basis for such medical applications, a few studies have already addressed the structural and functional analysis of ML-I in complex with ligands. In continuation of these efforts, we are reporting the crystal structure of ML from Viscum album in complex with the nucleic acid oxidation product 4-N-furfurylcytosine (FC) refined to 2.85 Å resolution. FC is known to be involved in different metabolic pathways related to oxidative stress and DNA modification. METHODS: X-ray suitable hexagonal crystals of the ML-I/FC complex were grown within four days at 294 K using the hanging drop vapor diffusion method. Diffraction data were collected up to a resolution of 2.85 Å. The ligand affinity was verified by in-silico docking. RESULTS: The high-resolution structure was refined subsequently to analyze particularly the active site conformation and a binding epitope of 4-N-furfurylcytosine. A distinct 2Fo-Fc electron density at the active site was interpreted as a single FC molecule. The specific binding of FC is achieved also through hydrophobic interactions involving Tyr76A, Tyr115A, Glu165A, and Leu157A of the ML-I A-chain. The binding energy of FC to the active site of ML-I was calculated as well to be -6.03 kcal mol-1. CONCLUSION: In comparison to other reported ML-I complexes, we observed distinct differences in the vicinity of the nucleic acid base binding site upon interaction with FC. Therefore, data obtained will provide new insights in understanding the specificity, inhibition, and cytotoxicity of the ML-I A-chain, and related RIPs.


Assuntos
Citosina/análogos & derivados , Citosina/síntese química , Furanos/síntese química , Proteínas Inativadoras de Ribossomos Tipo 2/química , Toxinas Biológicas/química , Viscum album/química , Adenina/química , Domínio Catalítico , Cristalização , Cristalografia por Raios X , Interações Hidrofóbicas e Hidrofílicas , Cinetina/química , Ligantes , Simulação de Acoplamento Molecular , Conformação Proteica , Proteínas Inativadoras de Ribossomos Tipo 2/isolamento & purificação , Toxinas Biológicas/isolamento & purificação
9.
Biochim Biophys Acta Gen Subj ; 1862(3): 460-473, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29154940

RESUMO

BACKGROUND: Sambucus ebulus is a rich source of ribosome-inactivating proteins (RIPs) and RIP-related lectins generated from multiple genes. These proteins differ in their structure, enzymatic activity and sugar binding specificity. METHODS: We have purified and characterized ebulin-RP from S. ebulus leaves and determined the amino acid sequence by cDNA cloning. Cytotoxicity was studied in a variety of cancer cells and a comparative study of the ability of ebulin-RP to bind sugars using "in vitro" and "in silico" approaches was performed. RESULTS: Ebulin-RP is a novel heterodimeric type 2 RIP present in S. ebulus leaves together with the type 2 RIP ebulin l, which displayed rRNA N-glycosidase activity but unlike ebulin l, lacked functional sugar binding domains. As a consequence of changes in its B-chain, ebulin-RP displayed lower cytotoxicity than ebulin l towards cancer cells and induced apoptosis as the predominant pattern of cell death. CONCLUSIONS: Ebulin-RP is a novel member of the ebulin gene family with low cytotoxicity as a result of deficient sugar binding domains. Type 2 RIP genes from Sambucus have evolved to render proteins with different sugar affinities that may be related to different biological activities and could result in an advantage for the plant. GENERAL SIGNIFICANCE: The ebulin family of RIPs and lectins can serve as a good model for studying the evolutionary process which may have occurred in RIPs. The lack of cytotoxicity of ebulin-RP makes it a good candidate as a toxic moiety in the construction of immunotoxins and conjugates directed against specific targets.


Assuntos
Citotoxinas/isolamento & purificação , Proteínas Inativadoras de Ribossomos Tipo 2/isolamento & purificação , Sambucus/enzimologia , Açúcares/metabolismo , Sequência de Aminoácidos , Animais , Apoptose/efeitos dos fármacos , Sítios de Ligação , Linhagem Celular , Linhagem Celular Tumoral , Sistema Livre de Células , Citotoxinas/química , Citotoxinas/metabolismo , Citotoxinas/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Evolução Molecular , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Camundongos , Modelos Moleculares , Simulação de Acoplamento Molecular , Ácidos Nucleicos/efeitos dos fármacos , Filogenia , Folhas de Planta/enzimologia , Conformação Proteica , Domínios Proteicos , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Proteínas Inativadoras de Ribossomos Tipo 2/química , Proteínas Inativadoras de Ribossomos Tipo 2/metabolismo , Proteínas Inativadoras de Ribossomos Tipo 2/farmacologia , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
10.
Molecules ; 22(1)2017 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-28067841

RESUMO

Elderberry contains healthy low molecular weight nutraceuticals and lectins which are sequence-related to the elderberry allergen Sam n1. Some of these lectins are type II ribosome-inactivating proteins. The sensitivity of native lectins present in elderberry fruits and bark to the proteolysis triggered by in vitro simulated gastric and duodenal fluids has been investigated. It was found that these lectins are refractory to proteolysis. Nonetheless, incubation for 5-10 min in a boiling water bath completely sensitized them to the hydrolytic enzymes in vitro. Under these conditions neither total Folin-Ciocalteau's reagent reactive compounds, total anthocyanins and the mixture of cyanidin-3-glucoside plus cyanidin-3-sambubioside, nor antioxidant and free-radical scavenging activities were affected by more than 10% for incubations of up to 20 min. Therefore, short-time heat treatment reduces potential allergy-related risks deriving from elderberry consumption without seriously affecting its properties as an antioxidant and free-radical scavenging food.


Assuntos
Alérgenos/química , Antioxidantes/química , Frutas/química , Lectinas de Plantas/química , Proteínas Inativadoras de Ribossomos Tipo 2/química , Sambucus nigra/química , Alérgenos/isolamento & purificação , Antioxidantes/isolamento & purificação , Temperatura Alta , Pepsina A/química , Casca de Planta/química , Extratos Vegetais/química , Lectinas de Plantas/isolamento & purificação , Plantas Medicinais , Estabilidade Proteica , Proteólise , Proteínas Inativadoras de Ribossomos Tipo 2/isolamento & purificação , Espanha
11.
J Membr Biol ; 250(1): 77-87, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27837242

RESUMO

Fluorescence correlation spectroscopy (FCS) is a sensitive analytical tool for investigation of processes accompanied by changes in the mobility of molecules and complexes. In the present work, peak intensity analysis (PIA) in combination with the solution stirring using FCS setup was applied to explore the interaction between fluorescently labeled protein ligands and corresponding receptors located on membranes. In the system composed of biotinylated liposomes and fluorescently labeled streptavidin as a ligand, PIA allowed us to determine the optimum receptor concentration and demonstrate the essential dependence of the binding efficacy on the length of the linker between the biotin group and the polar head group of the lipid. The binding was dependent on the size of liposomes which was varied by lipid extrusion through filters of different pore diameters. The sensitivity of the method was higher with the liposomes of larger sizes. The PIA approach can be applied not only to liposomes but also to relatively large objects, e.g., erythrocytes or Sepharose beads derivatized with lactose as a receptor for the binding of viscumin and ricin.


Assuntos
Eritrócitos/metabolismo , Lipídeos/química , Proteínas/química , Espectrometria de Fluorescência , Animais , Biotina , Bovinos , Lipossomos/química , Tamanho da Partícula , Ligação Proteica , Proteínas/metabolismo , Proteínas Inativadoras de Ribossomos Tipo 2/química , Proteínas Inativadoras de Ribossomos Tipo 2/metabolismo , Ricina/química , Ricina/metabolismo , Coloração e Rotulagem , Toxinas Biológicas/química , Toxinas Biológicas/metabolismo
12.
Food Chem ; 220: 324-330, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-27855907

RESUMO

Ebulin f and SELfd are two lectins of Sambucus ebulus L. that show different stability and digestibility properties in gastric fluid due to their structural differences which may explain their different toxicological profiles. The main aim was to determine the effects of pH, temperature and sugar binding on the intrinsic structures of both proteins by fluorescence analyses. Quenching experiments were conducted, under different pH and temperature conditions, with acrylamide (uncharged) and iodide (charged), to study the possible changes of their intrinsic fluorescence. Results revealed that the native structure of SELfd is more folded than that of ebulin f. At pH 2.0, ebulin f displayed a more open structure than at neutral pH. It can be concluded that this is the main reason why ebulin f is accessible to pepsin action and more sensitive to degradation, in contrast to SELfd as we reported previously.


Assuntos
Lectinas/química , Proteínas Inativadoras de Ribossomos Tipo 2/química , Sambucus/química , Concentração de Íons de Hidrogênio , Pepsina A/metabolismo , Conformação Proteica , Temperatura
13.
Mol Cell Biochem ; 426(1-2): 87-99, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27868169

RESUMO

Leukemia is among the most aggressive and prevalent human malignant carcinoma. Chemotherapy is the preferred therapeutic strategy; however, recurrence of cancer and non-selective cytotoxicity are the major concerns. Unlike synthetic chemotherapeutic agents, mistletoe ribosome-inactivating protein (RIP) displays anti-tumor function in various types of cancers. However, its effect on leukemia cells is little explored. In this study, we assessed the impact of Viscum articulatum RIP (Articulatin-D) on the survival of acute T-cell leukemia cells and the involved molecular and cellular mechanisms. Cell proliferation assay showed that Articulatin-D suppressed the viability of leukemia cells selectively. We further confirmed that the elevation of mitochondrial membrane potential and exposure of phosphatidylserine are the early events of apoptosis induction in Articulatin-D-treated Jurkat cells. Subsequently, we found that Articulatin-D treatment induces apoptosis in Jurkat cells in a time- and concentration-dependent manner. In conclusion, we provided evidence that Articulatin-D efficiently activates caspase-8 involved in extrinsic pathway of apoptosis induction, which ultimately results in caspase-3-dependent DNA fragmentation of Jurkat cells. Further evaluation of Articulatin-D in cell culture and animal models may provide novel information on selective cytotoxicity to acute T-cell leukemia and its involvement in targeting tumor cell survival pathways.


Assuntos
Apoptose/efeitos dos fármacos , Caspase 8/metabolismo , Proliferação de Células/efeitos dos fármacos , Preparações de Plantas/farmacologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Proteínas Inativadoras de Ribossomos Tipo 2/farmacologia , Toxinas Biológicas/farmacologia , Viscum/química , Fragmentação do DNA/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Humanos , Células Jurkat , Preparações de Plantas/química , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Proteínas Inativadoras de Ribossomos Tipo 2/química , Toxinas Biológicas/química
14.
Molecules ; 21(11)2016 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-27809255

RESUMO

PEGylation is a well-established and effective strategy to decrease immunogenicity, which can increase the stability and in vivo half-life time. However, the generation of multi-site modified products is inevitable due to the lysine chemistry, which will bring difficulties in subsequent research, such as purification and quantification. Site-specific modification by mPEG-succinimidyl carbonate (mPEG-SC) is a widely used method for N-terminal conjugation. In this study, we used it for site-directed modification on two ribosome-inactivating proteins (RIPs), alpha-momorcharin (α-MMC) and momordica anti-HIV protein (MAP30), from Momordica charantia L. According to the optimization of previous modification conditions, we compared Macro-Cap SP with SP-Sepharose FF chromatography for separating the final mPEGylated RIPs. Two kinds of methods both can obtain homogenous mPEGylated RIPs which were identified by sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing electrophoresis (IEF), and matrix-assisted laser desorption ionization-time of flight/time of flight (MALDI-TOF/TOF) analysis. We also used iodine staining method to detect the amount of unmodified PEG. Furthermore, the inhibition activity of both mPEGylated and non-PEGylated RIPs against human lung adenocarcinoma epithelial A549 cells was detected. All of the results suggested that the mPEGylated α-MMC/MAP30 might be potentially developed as new anti-tumor drugs.


Assuntos
Adenocarcinoma/tratamento farmacológico , Antineoplásicos Fitogênicos , Neoplasias Pulmonares/tratamento farmacológico , Momordica charantia/química , Polietilenoglicóis/química , Proteínas Inativadoras de Ribossomos Tipo 2 , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Linhagem Celular Tumoral , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Proteínas Inativadoras de Ribossomos Tipo 2/química , Proteínas Inativadoras de Ribossomos Tipo 2/farmacologia
15.
PLoS One ; 11(7): e0159653, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27459300

RESUMO

In contrast to conventional antibiotics, which microorganisms can readily evade, it is nearly impossible for a microbial strain that is sensitive to antimicrobial proteins to convert to a resistant strain. Therefore, antimicrobial proteins and peptides that are promising alternative candidates for the control of bacterial infections are under investigation. The MAP30 protein of Momordica charantia is a valuable type I ribosome-inactivating protein (RIP) with anti-HIV and anti-tumor activities. Whereas the antimicrobial activity of some type I RIPs has been confirmed, less attention has been paid to the antimicrobial activity of MAP30 produced in a stable, easily handled, and extremely cost-effective protein-expression system. rMAP30-KDEL was expressed in Nicotiana tobacum hairy roots, and its effect on different microorganisms was investigated. Analysis of the extracted total proteins of transgenic hairy roots showed that rMAP30-KDEL was expressed effectively and that this protein exhibited significant antibacterial activity in a dose-dependent manner. rMAP30-KDEL also possessed thermal and pH stability. Bioinformatic analysis of MAP30 and other RIPs regarding their conserved motifs, amino-acid contents, charge, aliphatic index, GRAVY value, and secondary structures demonstrated that these factors accounted for their thermophilicity. Therefore, RIPs such as MAP30 and its derived peptides might have promising applications as food preservatives, and their analysis might provide useful insights into designing clinically applicable antibiotic agents.


Assuntos
Fármacos Anti-HIV , Antineoplásicos Fitogênicos , Expressão Gênica , Nicotiana/genética , Raízes de Plantas/genética , Proteínas Recombinantes/genética , Proteínas Inativadoras de Ribossomos Tipo 2/genética , Sequência de Aminoácidos , Fármacos Anti-HIV/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Sequência Conservada , Escherichia coli/efeitos dos fármacos , Ordem dos Genes , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Testes de Sensibilidade Microbiana , Plantas Geneticamente Modificadas , Plasmídeos/genética , Matrizes de Pontuação de Posição Específica , Domínios e Motivos de Interação entre Proteínas , Estabilidade Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/farmacologia , Proteínas Inativadoras de Ribossomos Tipo 2/química , Proteínas Inativadoras de Ribossomos Tipo 2/isolamento & purificação , Proteínas Inativadoras de Ribossomos Tipo 2/farmacologia , Temperatura
16.
Bull Exp Biol Med ; 160(6): 823-6, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27165082

RESUMO

Magnetite particles modified by polyethylene glycol with a molecular weight of 3 kDa and hydrodynamic diameter of ~60 nm were used. Plant lectin viscumin covalently immobilized on these nanoparticles retained its binding activity. Immunochemical characteristics of conjugated viscumin were evaluated using monoclonal antibodies. The resultant conjugate with a hydrodynamic diameter of 70 nm was used for studies of binding and internalization by target cells. Binding of viscumin and its conjugate was determined by receptors containing terminal galactose, while intracellular distribution varied. The model system presented in this study can be used for creation of drugs for target therapy.


Assuntos
Nanopartículas de Magnetita/química , Nanoconjugados/química , Proteínas Inativadoras de Ribossomos Tipo 2/química , Toxinas Biológicas/química , Linhagem Celular Tumoral , Glioblastoma , Humanos , Tamanho da Partícula , Proteínas Inativadoras de Ribossomos Tipo 2/metabolismo , Toxinas Biológicas/metabolismo
17.
J Biosci ; 40(5): 929-41, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26648038

RESUMO

The structures of nine independent crystals of bitter gourd seed lectin (BGSL), a non-toxic homologue of type II RIPs, and its sugar complexes have been determined. The four-chain, two-fold symmetric, protein is made up of two identical two-chain modules, each consisting of a catalytic chain and a lectin chain, connected by a disulphide bridge. The lectin chain is made up of two domains. Each domain carries a carbohydrate binding site in type II RIPs of known structure. BGSL has a sugar binding site only on one domain, thus impairing its interaction at the cell surface. The adenine binding site in the catalytic chain is defective. Thus, defects in sugar binding as well as adenine binding appear to contribute to the non-toxicity of the lectin. The plasticity of the molecule is mainly caused by the presence of two possible well defined conformations of a surface loop in the lectin chain. One of them is chosen in the sugar complexes, in a case of conformational selection, as the chosen conformation facilitates an additional interaction with the sugar, involving an arginyl residue in the loop. The N-glycosylation of the lectin involves a plant-specific glycan while that in toxic type II RIPs of known structure involves a glycan which is animal as well as plant specific.


Assuntos
Lectinas/química , Lectinas/toxicidade , Momordica charantia/química , Proteínas de Plantas/química , Adenina/metabolismo , Sítios de Ligação , Sequência de Carboidratos , Cristalografia por Raios X , Glicosilação , Lectinas/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Proteínas de Plantas/metabolismo , Polissacarídeos/química , Polissacarídeos/metabolismo , Conformação Proteica , Dobramento de Proteína , Proteínas Inativadoras de Ribossomos Tipo 2/química , Proteínas Inativadoras de Ribossomos Tipo 2/metabolismo , Proteínas Inativadoras de Ribossomos Tipo 2/toxicidade , Homologia de Sequência de Aminoácidos
18.
Protein Expr Purif ; 111: 9-17, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25797209

RESUMO

MAP30 (Momordica Antiviral Protein 30 Kd), a single-stranded type-I ribosome inactivating protein, possesses versatile biological activities including anti-tumor abilities. However, the low efficiency penetrating into tumor cells hampers the tumoricidal effect of MAP30. This paper describes MAP30 fused with a human-derived cell penetrating peptide HBD which overcome the low uptake efficiency by tumor cells and exhibits higher anti-tumor bioactivity. MAP30 gene was cloned from the genomic DNA of Momordica charantia and the recombinant plasmid pET28b-MAP30-HBD was established and transferred into Escherichia coli BL21 (DE3). The recombinant MAP30-HBD protein (rMAP30-HBD) was expressed in a soluble form after being induced by 0.5mM IPTG for 14h at 15°C. The recombinant protein was purified to greater than 95% purity with Ni-NTA affinity chromatography. The rMAP30-HBD protein not only has topological inactivation and protein translation inhibition activity but also showed significant improvements in cytotoxic activity compared to that of the rMAP30 protein without HBD in the tested tumor cell lines, and induced higher apoptosis rates in HeLa cells analyzed by Annexin V-FITC with FACS. This paper demonstrated a new method for improving MAP30 protein anti-tumor activity and might have potential applications in cancer therapy area.


Assuntos
Antineoplásicos , Peptídeos Penetradores de Células , Neoplasias/tratamento farmacológico , Proteínas Inativadoras de Ribossomos Tipo 2 , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Peptídeos Penetradores de Células/biossíntese , Peptídeos Penetradores de Células/química , Peptídeos Penetradores de Células/genética , Peptídeos Penetradores de Células/isolamento & purificação , Peptídeos Penetradores de Células/farmacologia , Células HeLa , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/farmacologia , Proteínas Inativadoras de Ribossomos Tipo 2/biossíntese , Proteínas Inativadoras de Ribossomos Tipo 2/química , Proteínas Inativadoras de Ribossomos Tipo 2/genética , Proteínas Inativadoras de Ribossomos Tipo 2/isolamento & purificação , Proteínas Inativadoras de Ribossomos Tipo 2/farmacologia
19.
Toxins (Basel) ; 7(3): 648-58, 2015 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-25723322

RESUMO

Sambucus ebulus L. (dwarf elder) is a medicinal plant, the usefulness of which also as food is restricted due to its toxicity. In the last few years, both the chemistry and pharmacology of Sambucus ebulus L. have been investigated. Among the structural and functional proteins present in the plant, sugar-binding proteins (lectins) with or without anti-ribosomal activity and single chain ribosome-inactivating proteins (RIPs) have been isolated. RIPs are enzymes (E.C. 3.2.2.22) that display N-glycosidase activity on the 28S rRNA subunit, leading to the inhibition of protein synthesis by arresting the step of polypeptide chain elongation. The biological role of all these proteins is as yet unknown. The evidence suggests that they could be involved in the defense of the plant against predators and viruses or/and a nitrogen store, with an impact on the nutritional characteristics and food safety. In this mini-review we describe all the isoforms of ebulin that have to date been isolated from dwarf elder, as well as their functional characteristics and potential uses, whilst highlighting concern regarding ebulin toxicity.


Assuntos
Proteínas Inativadoras de Ribossomos Tipo 2/química , Sambucus/química , Clonagem Molecular , Lectinas/química , Lectinas/isolamento & purificação , Plantas Medicinais/química , Biossíntese de Proteínas , RNA Ribossômico 28S/genética , Proteínas Inativadoras de Ribossomos Tipo 2/isolamento & purificação
20.
Int J Pharm ; 483(1-2): 188-99, 2015 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-25681721

RESUMO

An essential in vivo drug delivery system of a momordica anti-HIV protein, MAP30, was developed through encapsulating in chemically synthesized matrices of zirconium egg- and soy-phosphatidylcholines, abbreviated to Zr/EPC and Zr/SPC, respectively. Matrices were characterized by transmission electron microscopy and powder X-ray diffractometry studies. Zr/EPC granule at an approximate diameter of 69.43±7.78 nm was a less efficient encapsulator than the granule of Zr/SPC. Interlayer spacing of the matrices encapsulating MAP30 increased from 8.8 and 9.7 Å to 7.4 and 7.9 nm, respectively. In vivo kinetics on degradation and protein release was performed by analyzing the serum sampling of intravenously injected SPF chickens. The first order and biphasic variations were obtained for in vivo kinetics using equilibrium dialysis. Antimicrobial and anti-HIV assays yielded greatly decreased MIC50 and EC50 values of nanoformulated MAP30. An acute toxicity of MAP30 encapsulated in Zr/EPC occurred at a single intravenous dose above 14.24 mg/kg bw in NIH/KM/ICR mice. The folding of MAP30 from Zr/EPC sustained in vivo chickens for more than 8 days in high performance liquid chromatography assays. These matrices could protect MAP30 efficiently with strong structure retention, lowered toxicity and prolonged in vivo life.


Assuntos
Antibacterianos/farmacologia , Fármacos Anti-HIV/farmacologia , Bactérias/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , HIV-1/efeitos dos fármacos , Nanocápsulas/química , Fosfatidilcolinas/química , Proteínas Inativadoras de Ribossomos Tipo 2/metabolismo , Zircônio/química , Animais , Antibacterianos/química , Antibacterianos/metabolismo , Fármacos Anti-HIV/química , Fármacos Anti-HIV/metabolismo , Injeções Intravenosas , Camundongos , Camundongos Endogâmicos , Estrutura Molecular , Nanocápsulas/administração & dosagem , Tamanho da Partícula , Fosfatidilcolinas/administração & dosagem , Proteínas Inativadoras de Ribossomos Tipo 2/administração & dosagem , Proteínas Inativadoras de Ribossomos Tipo 2/química , Propriedades de Superfície , Zircônio/administração & dosagem
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