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A novel cell-penetrating peptide (CPP) called FAM-Y4R4, with FAM as a fluorescent probe, was developed. Initially, we aimed to use Y4 as a supramolecular host for water-insoluble drugs, with R4 driving the complex into cells. However, an unexpected hurdle was discovered; the peptide self-assembled into amorphous aggregates, rendering it ineffective for our intended purpose. Molecular dynamics simulations revealed that intermolecular cation-π interactions between arginine and tyrosine caused this aggregation. By decorating the R4 sidechains with p-sulfonatocalix[4]arene (CX4), we successfully dissolved most of the aggregates, significantly improved the peptide's solubility and enhanced the cell uptake with MCF7 and A549 cells via both direct penetration and endocytosis. The binding strength between CX4 and R4, as well as the interaction between curcumin and tyrosines was quantified. Encouragingly, our results showed that FAM-Y4R4, with CX4, effectively delivered curcumin - as a model for poorly water-soluble drugs - into cells which exhibited potent anticancer activity. Using R4/CX4 instead of the conventional R7-9 oligoarginine-based CPP simplifies peptide synthesis and offers higher yields. CX4 shows promise for addressing aggregation issues in other peptides that undergo a similar aggregation mechanism.
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Peptides are a very critical class of pharmaceutical compounds that can control several signaling pathways and thereby affect many physiological and biochemical processes. Previous research suggests that both peptides and antibodies may serve as potent tools for research, diagnostics, vaccination, and therapeutics across diverse domains. The distinct attributes of peptides, like their profound tissue penetration, efficient cellular internalization, reduced immunogenicity, and adaptability to chemical modification, underscore their significance in biomedical applications. However, they also possess drawbacks such as lower affinity, poor absorption, low stability to proteolytic digestion, and rapid clearance. The advent of peptibodies is a significant advance that improves the limitations of both peptides and antibodies. Peptibodies, or Peptide-Fc fusions, represent a promising therapeutic modality comprising biologically active peptides fused to an Fc domain. The stability and efficacy of the peptide are enhanced by this fusion strategy, which overcomes some of the inherent limitations. Many peptibodies have been developed to treat conditions like cancer, diabetes, and lupus. Romiplostim and Dulaglutide are the only ones approved by the EMA and FDA, respectively. Given the growing significance of peptibodies in the pharmaceutical landscape, this investigation aims to explain key aspects encompassing the intrinsic properties of peptides, the intricacies of peptibody production, and their potential therapeutic applications.
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Peptídeos , Humanos , Peptídeos/química , Peptídeos/imunologia , Peptídeos/uso terapêutico , Animais , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/uso terapêutico , Fragmentos Fc das Imunoglobulinas/química , Anticorpos/química , Anticorpos/imunologiaRESUMO
Glioblastoma multiforme (GBM), is a frequent class of malignant brain tumors. Epigenetic therapy, especially with synergistic combinations is highly paid attention for aggressive solid tumors like GBM. Here, RSM optimization has been used to increase the efficient arrest of U87 and U251 cell lines due to synergistic effects. Cell lines were treated with SAHA, 5-Azacytidine, GSK-126, and PTC-209 individually and then RSM was used to find most effective combinations. Results showed that optimized combinations significantly reduce cell survival and induce cell cycle arrest and apoptosis in both cell lines. Expression of cyclin B1 and cyclin D1 were decreased while caspase3 increased expression.
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Apoptose , Sinergismo Farmacológico , Epigênese Genética , Glioblastoma , Humanos , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/patologia , Linhagem Celular Tumoral , Apoptose/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Azacitidina/farmacologia , Azacitidina/administração & dosagem , Sobrevivência Celular/efeitos dos fármacos , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Vorinostat/farmacologia , Vorinostat/administração & dosagem , Proliferação de Células/efeitos dos fármacos , Ciclina D1/genética , Ciclina D1/metabolismoRESUMO
Protein aggregation is a complex process with several stages that lead to the formation of complex structures and shapes with a broad variability in stability and toxicity. The aggregation process is affected by various factors and environmental conditions that disrupt the protein's original state, including internal factors like mutations, expression levels, and polypeptide chain truncation, as well as external factors, such as dense molecular surroundings, post-translation modifications, and interactions with other proteins, nucleic acids, small molecules, metal ions, chaperones, and lipid membranes. During the aggregation process, the biological activity of an aggregating protein may be reduced or eliminated, whereas the resulting aggregates may have the potential to be immunogenic, or they may have other undesirable properties. Finding the cause(s) of protein aggregation and controlling it to an acceptable level is among the most crucial topics of research in academia and biopharmaceutical companies. This chapter aims to review intrinsic pathways of protein aggregation and potential extrinsic variables that influence this process.
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Amiloide , Amiloide/metabolismo , Humanos , Animais , Agregados ProteicosRESUMO
Misfolded proteins assemble into fibril structures that are called amyloids. Unlike usually folded proteins, misfolded fibrils are insoluble and deposit extracellularly or intracellularly. Misfolded proteins interrupt the function and structure of cells and cause amyloid disease. There is increasing evidence that the most pernicious species are oligomers. Misfolded proteins disrupt cell function and cause cytotoxicity by calcium imbalance, mitochondrial dysfunction, and intracellular reactive oxygen species. Despite profound impacts on health, social, and economic factors, amyloid diseases remain untreatable. To develop new therapeutics and to understand the pathological manifestations of amyloidosis, research into the origin and pathology of amyloidosis is urgently needed. This chapter describes the basic concept of amyloid disease and the function of atypical amyloid deposits in them.
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Amiloide , Humanos , Amiloide/metabolismo , Animais , Amiloidose/patologia , Amiloidose/metabolismoRESUMO
In order for an ordered protein to perform its specific function, it must have a specific molecular structure. Information about this structure is encoded in the protein's amino acid sequence. The unique functional state is achieved as a result of a specific process, known as protein folding. However, as a result of partial or complete unfolding of the polypeptide chain, proteins may misfold and aggregate, leading to the formation of various aggregated structures, such as like amyloid aggregates with the cross-ß structure. A variety of cellular biological processes can be affected by protein aggregates that consume essential factors necessary for maintaining proteostasis, which leads to the proteostasis imbalance and further accumulation of protein aggregates, often resulting in age-related neurodegenerative disease progression and aging. However, in addition to their well-established pathological effects, amyloids also play various physiological roles, and many important biological processes involve such 'functional amyloids'. This chapter represents a brief overview of the protein aggregation phenomenon outlines a timeline provides of some key discoveries in this exciting field.
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Agregados Proteicos , Humanos , Animais , Amiloide/metabolismo , Amiloide/química , Agregação Patológica de Proteínas/metabolismo , Dobramento de Proteína , Proteínas/metabolismo , Proteínas/químicaRESUMO
The occurrence of antibiotic resistance on common bacterial agents and the need to use new generations of antibiotics have led to the use of various strategies for production. Taking inspiration from nature, using bio-imitation patterns, in addition to the low cost of production, is advantageous and highly accurate. In this research, we were able to control the temperature, shake, and synthesis time of the synthesis conditions of Bacillus megaterium bacteria as a model for the synthesis of magnetic iron nanoparticles and optimize the ratio of reducing salt to bacterial regenerating agents as well as the concentration of salt to create iron oxide nanoparticles with more favorable properties and produced with more antibacterial properties. Bacterial growth was investigated by changing the incubation times of pre-culture and overnight culture in the range of the logarithmic phase. The synthesis time, salt ratio, and concentration were optimized to achieve the size, charge, colloidal stability, and magnetic and antibacterial properties of nanoparticles. The amount of the effective substance produced by the bacteria was selected by measuring the amount of the active substance synthesized using the free radical reduction (DPPH) method. With the help of DPPH, the duration of the synthesis was determined to be one week. Characterizations such as UV-vis spectroscopy, FTIR, FESEM, X-ray, and scattering optical dynamics were performed and showed that the nanoparticles synthesized with a salt concentration of 80 mM and a bacterial suspension to salt ratio of 2:1 are smaller in size and have a light scattering index, a PDI index close to 0.1, and a greater amount of reducing salt used in the reaction during one week compared to other samples. Moreover, they had more antibacterial properties than the concentration of 100 mM. As a result, better characteristics and more antibacterial properties than common antibiotics were created on E. coli and Bacillus cereus.
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This study investigates the performance of personalised middle ear prostheses under static pressure through a combined approach of numerical analysis and experimental validation. The sound transmission performances of both normal and reconstructed middle ears undergo changes under high positive or negative pressure within the middle ear cavity. This pressure fluctuation has the potential to result in prosthesis displacement/extrusion in patients. To optimise the design of middle ear prostheses, it is crucial to consider various factors, including the condition of the middle ear cavity in which the prosthesis is placed. The integration of computational modelling techniques with non-invasive imaging modalities has demonstrated significant promise and distinct prospects in middle ear surgery. In this study, we assessed the efficacy of Finite Element (FE) analysis in modelling the responses of both normal and reconstructed middle ears to elevated static pressure within the ear canal. The FE model underwent validation using experimental data derived from human cadaveric temporal bones before progressing to subsequent investigations. Afterwards, we assessed stapes and umbo displacements in the reconstructed middle ear under static pressure, with either a columella-type prosthesis or a prosthetic incus, closely resembling a healthy incus. Results indicated the superior performance of the prosthetic incus in terms of both sound transmission to the inner ear and stress distribution patterns on the TM, potentially lowering the risk of prosthesis displacement/extrusion. This study underscores the potential of computational analysis in middle ear surgery, encompassing aspects such as prosthesis design, predicting outcomes in ossicular chain reconstruction (OCR), and mitigating experimental costs.
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Orelha Média , Prótese Ossicular , Humanos , Orelha Média/cirurgia , Estribo , Bigorna/cirurgia , Desenho de PróteseRESUMO
In multiple sclerosis, lesions are formed in various areas of the CNS, which are characterized by reactive gliosis, immune cell infiltration, extracellular matrix changes and demyelination. CAQK peptide (peptide sequence: cysteine-alanine-glutamine-lysine) was previously introduced as a targeting peptide for the injured site of the brain. In the present study, we aimed to develop a multifunctional system using nanoparticles coated by CAQK peptide, to target the demyelinated lesions in animal model of multiple sclerosis. We investigated the binding of fluorescein amidite-labelled CAQK and fluorescein amidite-labelled CGGK (as control) on mouse brain sections. Then, the porous silicon nanoparticles were synthesized and coupled with fluorescein amidite-labelled CAQK. Five days after lysolecithin-induced demyelination, male mice were intravenously injected with methylprednisolone-loaded porous silicon nanoparticles conjugated to CAQK or the same amount of free methylprednisolone. Our results showed that fluorescein amidite-labelled CAQK recognizes demyelinated lesions in brain sections of animal brains injected with lysolecithin. In addition, intravenous application of methylprednisolone-loaded nanoparticle porous silicon conjugated to CAQK at a single dose of 0.24â mg reduced the levels of microglial activation and astrocyte reactivation in the lesions of mouse corpus callosum after 24 and 48â h. No significant effect was observed following the injection of the same dose of free methylprednisolone. CAQK seems a potential targeting peptide for delivering drugs or other biologically active chemicals/reagents to the CNS of patients with multiple sclerosis. Low-dose methylprednisolone in this targeted drug delivery system showed significant beneficial effect.
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Background: Adenoid cystic carcinoma is a slow-growing malignancy that most often occurs in the salivary glands. Currently, no FDA-approved therapeutic target or diagnostic biomarker has been identified for this cancer. The aim of this study was to find new therapeutic and diagnostic targets using bioinformatics methods. Methods: We extracted the gene expression information from two GEO datasets (including GSE59701 and GSE88804). Different expression genes between adenoid cystic carcinoma (ACC) and normal samples were extracted using R software. The biochemical pathways involved in ACC were obtained by using the Enrichr database. PPI network was drawn by STRING, and important genes were extracted by Cytoscape. Real-time PCR and immunohistochemistry were used for biomarker verification. Results: After analyzing the PPI network, 20 hub genes were introduced to have potential as diagnostic and therapeutic targets. Among these genes, PLCG1 was presented as new biomarker in ACC. Furthermore, by studying the function of the hub genes in the enriched biochemical pathways, we found that insulin-like growth factor type 1 receptor and PPARG pathways most likely play a critical role in tumorigenesis and drug resistance in ACC and have a high potential for selection as therapeutic targets in future studies. Conclusion: In this study, we achieved the recognition of the pathways involving in ACC pathogenesis and also found potential targets for treatment and diagnosis of ACC. Further experimental studies are required to confirm the results of this study.
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Carcinoma Adenoide Cístico , Neoplasias das Glândulas Salivares , Humanos , Carcinoma Adenoide Cístico/tratamento farmacológico , Carcinoma Adenoide Cístico/genética , Carcinoma Adenoide Cístico/metabolismo , Neoplasias das Glândulas Salivares/tratamento farmacológico , Neoplasias das Glândulas Salivares/genética , Neoplasias das Glândulas Salivares/metabolismo , BiomarcadoresRESUMO
Drug development for multiple sclerosis (MS) clinical management focuses on both neuroprotection and repair strategies, and is challenging due to low permeability of the blood-brain barrier, off-target distribution, and the need for high doses of drugs. The changes in the extracellular matrix have been documented in MS patients. It has been shown that the expression of nidogen-1 increases in MS lesions. Laminin forms a stable complex with nidogen-1 through a heptapeptide which was selected to target the lesion area in this study. Here we showed that the peptide binding was specific to the injured area following lysophosphatidylcholine (LPC) induced demyelination. In vivo data showed enhanced delivery of the peptide-functionalized gold nanoparticles (Pep-GNPs) to the lesion area. In addition, Pep-GNPs administration significantly enhanced myelin content and reduced astrocyte/microglia activation. Results demonstrated the possibility of using this peptide to target and treat lesions in patients suffering from MS.
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Ouro , Nanopartículas Metálicas , Humanos , Bainha de Mielina , Peptídeos/farmacologiaRESUMO
BACKGROUND: Colorectal cancer is one of the most common cancer and the third leading cause of death worldwide. Increased generation of reactive oxygen species (ROS) is observed in many types of cancer cells. Several studies have reported that an increase in ROS production could affect the expression of proteins involved in ROS-scavenging, detoxification and drug resistance. Nuclear factor erythroid 2 related factor 2 (Nrf2) is a known transcription factor for cellular response to oxidative stress. Several researches exhibited that Nrf2 could exert multiple functions and expected to be a promising therapeutic target in many cancers. Here, Nrf2 was knocked down in colorectal cancer cell line HT29 and changes that occurred in signaling pathways and survival mechanisms were evaluated. METHODS: The influence of chemotherapy drugs (doxorubicin and cisplatin), metastasis and cell viability were investigated. To explore the association between specific pathways and viability in HT29-Nrf2-, proteomic analysis, realtime PCR and western blotting were performed. RESULTS: In the absence of Nrf2 (Nrf2-), ROS scavenging and detoxification potential were dramatically faded and the HT29-Nrf2- cells became more susceptible to drugs. However, a severe decrease in viability was not observed. Bioinformatic analysis of proteomic data revealed that in Nrf2- cells, proteins involved in detoxification processes, respiratory electron transport chain and mitochondrial-related compartment were down regulated. Furthermore, proteins related to MAPKs, JNK and FOXO pathways were up regulated that possibly helped to overcome the detrimental effect of excessive ROS production. CONCLUSIONS: Our results revealed MAPKs, JNK and FOXO pathways connections in reducing the deleterious effect of Nrf2 deficiency, which can be considered in cancer therapy.
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Neoplasias Colorretais , Proteômica , Linhagem Celular , Neoplasias Colorretais/genética , Humanos , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismoRESUMO
Insulin and its homologous are the most utilized protein drugs due to their role in diabetic patients' treatment. Insulin forms amyloid-like fibrils in vivo at the injection site. Therefore, the study of its fibrillation mechanism and designing efficient inhibitors have high importance in the pharmaceutical industry. Insulin fibrils are formed at both acidic and neutral pH in vitro. Overall, this process involves the dissociation of hexameric form to monomeric, partially dissociating the native monomeric form, nuclei formation, and finally converting oligomers to large ordered aggregates. Intermediate and terminal species are different pathologically. This review is focused on the research works dedicated to the inhibition of insulin fibril formation. The inhibitors include various polyphenols, natural compounds, nanoparticles, and synthetic chemicals/peptides, as well as the classification of inhibitors targets concerning protein fibrillation. Although most inhibitors stabilize the native structure of the protein and prevent the formation of partially folded species, there are other inhibitors that hinder other steps in the course of fibrillation. Also, several inhibitors were able to dissociate the pre-existing fibrils. Finding inhibition strategies could be beneficial for developing new inhibitors that are more efficient and can block the amyloid pathway in a specific desired stage.
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Amiloide , Insulina , Humanos , Insulina/química , Insulina/metabolismo , Cinética , Amiloide/química , Concentração de Íons de HidrogênioRESUMO
One of the advantages of surface plasmon resonance is its sensitivity and real-time analyses performed by this method. These characteristics allow us to further investigate the interactions of challenging proteins like Rap1-interacting factor 1 (Rif1). Rif1 is a crucial protein responsible for regulating different cellular processes including DNA replication, repair, and transcription. Mammalian Rif1 is yet to be fully characterized, partly because it is predicted to be intrinsically disordered for a large portion of its polypeptide. This protein has recently been the target of research as a potential biomarker in many cancers. Therefore, finding its most potent interacting partner is of utmost importance. Previous studies showed Rif1's affinity towards structured DNAs and amongst them, T6G24 was superior. Recent studies have shown mouse Rif1 (muRif1) C-terminal domain's (CTD) role in binding to G-quadruplexes (G4). There were many concerns in investigating the Rif1 and G4 interaction, which can be minimized using SPR. Therefore, for the first time, we have assessed its binding with G4 at nano-molar concentrations with SPR which seems to be crucial for its binding analyses. Our results indicate that muRif1-CTD has a high affinity for this G4 sequence as it shows a very low KD (6 ± 1 nM).
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Quadruplex G , Proteínas de Ligação a Telômeros , Animais , Replicação do DNA/fisiologia , Camundongos , Ligação Proteica , Ressonância de Plasmônio de Superfície , Proteínas de Ligação a Telômeros/genética , Proteínas de Ligação a Telômeros/metabolismoRESUMO
Herein proteomic profiling of the rat hippocampus from the kindling and pilocarpine models of epilepsy was performed to achieve new potential targets for treating epileptic seizures. A total of 144 differently expressed proteins in both left and right hippocampi by two-dimensional electrophoresis coupled to matrix-assisted laser desorption-mass spectrometry were identified across the rat models of epilepsy. Based on network analysis, the majority of differentially expressed proteins were associated with Ca2+ homeostasis. Changes in ADP-ribosyl cyclase (ADPRC), lysophosphatidic acid receptor 3 (LPAR3), calreticulin, ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1), synaptosomal nerve-associated protein 25 (SNAP 25) and transgelin 3 proteins were probed by Western blot analysis and validated using immunohistochemistry. Inhibition of calcium influx by 8-Bromo-cADP-Ribose (8-Br-cADPR) and 2-Aminoethyl diphenylborinate (2-APB) which act via the ADPRC and LPAR3, respectively, attenuated epileptic seizures. Considering a wide range of molecular events and effective role of calcium homeostasis in epilepsy, polypharmacy with multiple realistic targets should be further explored to reach the most effective treatments.
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Cálcio/metabolismo , Epilepsia/genética , Epilepsia/metabolismo , Hipocampo/metabolismo , Excitação Neurológica , Pilocarpina , Proteômica , ADP-Ribosil Ciclase/metabolismo , Animais , ADP-Ribose Cíclica/análogos & derivados , ADP-Ribose Cíclica/fisiologia , Modelos Animais de Doenças , Eletroforese/métodos , Epilepsia/terapia , Homeostase , Masculino , Terapia de Alvo Molecular , Ratos Wistar , Receptores de Ácidos Lisofosfatídicos/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Proteína 25 Associada a Sinaptossoma/metabolismoRESUMO
In spite of long-term intensive scientific research efforts, there are still many issues concerning the mechanisms of epileptogenesis and epilepsy to be resolved. Temporal lobe, in particular hippocampus, is vulnerable to epileptogenic process. Herein, electrical kindling model of temporal lobe were analyzed using proteomic approach. A dramatic decrease in nicotinamide adenine dinucleotide (NAD+) level was exhibited during the kindling procedure in hippocampus. After stage 3, high CD38 expression was detected by qPCR, nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) and western blot analysis. An increase in expression of CD38/NADase activity was observed during the kindling procedure in hippocampus that suggest it as one of the most important NAD+ degrading enzymes during epileptogenesis. Subsequently, gene expression of CD38 metabolite related proteins (Ryr2, FKBP-12.6, Chrm1, mGluR1 and Cnx43) were examined. Among them, changes in the expression level of mGluR1 was more than other genes, which was also confirmed by LC MS/MS and western blotting analysis. These findings provided valuable information about changes in the expression of CD38/cADPR signaling pathway and suggest its crucial role during epileptogenesis.
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ADP-Ribosil Ciclase 1/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Convulsões/metabolismo , ADP-Ribosil Ciclase/metabolismo , Animais , Encéfalo/fisiologia , ADP-Ribose Cíclica/análogos & derivados , ADP-Ribose Cíclica/farmacologia , Modelos Animais de Doenças , Expressão Gênica/genética , Hipocampo/fisiologia , Homeostase/fisiologia , Excitação Neurológica/fisiologia , Masculino , Glicoproteínas de Membrana/metabolismo , NAD/metabolismo , Proteômica/métodos , Ratos , Ratos Wistar , Convulsões/fisiopatologia , Transdução de Sinais , Espectrometria de Massas em Tandem/métodosRESUMO
Platelets, with hemostasis and thrombosis activities, are one of the key components in the blood circulation. As a guard, they rapidly respond to any abnormal blood vessel injury signal and release their granules' contents, which induce their adhesion and aggregation on wound site for hemostasis. Recently, increasing evidence has indicated that platelets are critically involved in the growth and metastasis of cancer cells by releasing a variety of cytokines and chemokines to stimulate cancer cell proliferation and various angiogenic regulators to accelerate tumor angiogenesis. Platelets also secrete active transforming growth factor beta (TGF-ß) to promote the epithelial-mesenchymal transition of cancer cells and their extravasation from primary site, and form microthrombus on the surface of cancer cells to protect them from immune attack and high-speed shear force in the circulation. Therefore, blocking platelet-cancer cell interaction may be an attractive strategy to treat primary tumor and/or prevent cancer metastasis. However, systemic inhibition or depletion of platelets brings risk of severe bleeding complication. Cancer-associated-platelets-targeted nanomedicines and biomimetic nanomedicines coated with platelet membrane can be used for targeted anticancer drug delivery, due to their natural targeting ability to tumor cells and platelets. In the current review, we first summarized the platelet mechanisms of action in physiological condition and their multiple roles in cancer progression and conventional antiplatelet therapeutics. We then highlighted the recent progress on the design and fabrication of cancer-associated-platelet-targeted nanomedicines and platelet membrane coating nanomedicines for cancer therapy. Finally, we discussed opportunities and challenges and offered our thoughts for the future development. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology-Inspired Nanomaterials > Lipid-Based Structures.
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Antineoplásicos , Plaquetas , Nanomedicina , Neoplasias , Antineoplásicos/uso terapêutico , Hemostasia , Humanos , Neoplasias/tratamento farmacológicoRESUMO
The conversion of soluble proteins into amyloid fibrils has importance in protein chemistry, biology, biotechnology and medicine. A novel lipase from Pseudomonas sp. was previously shown to have an extremely high aggregation propensity. It was therefore herein studied to elucidate the physicochemical and structural determinants of this extreme behaviour. Amyloid-like structures were found to form in samples up to 2.5-3.0 M using Thioflavin T fluorescence and Congo red binding assays. However, dynamic light scattering (DLS), static light scattering and turbidimetry revealed the existence of aggregates up to 4.0 M urea, without amyloid-like structure. Two monomeric conformational states were detected with intrinsic fluorescence, 8-anilinonaphthalene-1-sulfonate (ANS) binding and circular dichroism. These were further characterized in 7.5 M and 4.5 M urea using enzymatic activity measurements, tryptophan fluorescence quenching, DLS and nuclear magnetic resonance (NMR) and were found to consist of a largely disordered and a partially folded state, respectively, with the latter appearing stable, cooperative, fairly compact, non-active, α-helical, with largely buried hydrophobic residues. The persistence of a stable structure up to high concentrations of urea, in the absence of sequence characteristics typical of a high intrinsic aggregation propensity, explains the high tendency of this enzyme to form amyloid-like structures.
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Lipase/isolamento & purificação , Dobramento de Proteína/efeitos dos fármacos , Ureia/química , Amiloide/química , Amiloidose/metabolismo , Dicroísmo Circular/métodos , Concentração de Íons de Hidrogênio , Lipase/química , Agregados Proteicos/fisiologia , Conformação Proteica/efeitos dos fármacos , Pseudomonas/genética , Pseudomonas/metabolismoRESUMO
α-Synuclein fibrillation is now regarded as a major pathogenic process in Parkinson's disease and its proteinaceous deposits are also detected in other neurological disorders including Alzheimer's disease. Therefore anti-amyloidegenic compounds may delay or prevent the progression of synucleinopathies disease. Molecular chaperones are group of proteins which mediate correct folding of proteins by preventing unsuitable interactions which may lead to aggregation. The objective of this study was to investigate the anti-amyloidogenic effect of molecular chaperone artemin on α-synuclein. As the concentration of artemin was increased up to 4 µg/ml, a decrease in fibril formation of α-synuclein was observed using thioflavin T (ThT) fluorescence and congo red (CR) assay. Transmission electron microscopy (TEM) images also demonstrated a reduction in fibrils in the presence of artemin. The secondary structure of α-synuclein was similar to its native form prior to fibrillation when incubated with artemin. A cell-based assay has shown that artemin inhibits α-synuclein aggregation and reduce cytotoxicity, apoptosis and reactive oxygen species (ROS) production. Our results revealed that artemin has efficient chaperon activity for preventing α-synuclein fibril formation and toxicity.
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Chaperonas Moleculares/metabolismo , Proteínas do Tecido Nervoso/metabolismo , alfa-Sinucleína/metabolismo , Apoptose , Linhagem Celular Tumoral , Sobrevivência Celular , Humanos , Agregados Proteicos , Agregação Patológica de Proteínas/metabolismo , Espécies Reativas de Oxigênio/análise , alfa-Sinucleína/química , alfa-Sinucleína/isolamento & purificaçãoRESUMO
BACKGROUND: Since vascular endothelial growth factor (VEGF) is a significant regulator of cancer angiogenesis, it is essential to develop a technology for its sensitive detection. Herein, we sensitized a chemiluminescence (CL) immunoassay through the combination of H2O2-sensitive TGA-CdTe quantum dot (QD) as signal transduction, dextran as a cross-linker to prepare enzyme-labeled antigen and the ultrahigh bioactivity of catalase (CAT) as reporter enzyme. RESULTS: Under the optimized experimental conditions, the chemiluminescence enzyme-linked immunosorbent assay (CL-ELISA) method can detect VEGF in the excellent linear range of 2-35,000 pg mL-1, with a detection limit (S/N = 3) of 0.5 pg mL-1 which was approximately ten times lower than the commercial colorimetric immunoassay. This proposed method has been successfully applied to the clinical determination of VEGF in the human serum samples, and the results illustrated an excellent correlation with the conventional ELISA method (R2 = 0.997). The suitable recovery rate of the method in the serum ranged from 97 to 107%, with a relative standard deviation of 1.2% to 13.4%. CONCLUSIONS: The novel immunoassay proposes a highly sensitive, specific, and stable method for very low levels detection of VEGF that can be used in the primary diagnosis of tumors. With the well-designed sensing platform, this approach has a broad potential to be applied for quantitative analysis of numerous disease-related protein biomarkers for which antibodies are available.