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Tumor immune evasion relies on the crosstalk between tumor cells and adaptive/innate immune cells. Immune checkpoints play critical roles in the crosstalk, and immune checkpoint inhibitors have achieved promising clinical effects. The long non-coding RNA taurine-upregulated gene 1 (TUG1) is upregulated in hepatocellular carcinoma (HCC). However, how TUG1 is upregulated and the effects on tumor immune evasion are incompletely understood. Here, METTL3-mediated m6A modification led to TUG1 upregulation is demonstrated. Knockdown of TUG1 inhibited tumor growth and metastasis, increased the infiltration of CD8+ T cells and M1-like macrophages in tumors, promoted the activation of CD8+ T cells through PD-L1, and improved the phagocytosis of macrophages through CD47. Mechanistically, TUG1 regulated PD-L1 and CD47 expressions by acting as a sponge of miR-141 and miR-340, respectively. Meanwhile, TUG1 interacted with YBX1 to facilitate the upregulation of PD-L1 and CD47 transcriptionally, which ultimately regulated tumor immune evasion. Clinically, TUG1 positively correlated with PD-L1 and CD47 in HCC tissues. Moreover, the combination of Tug1-siRNA therapy with a Pdl1 antibody effectively suppressed tumor growth. Therefore, the mechanism of TUG1 in regulating tumor immune evasion is revealed and can inform existing strategies targeting TUG1 for enhancing HCC immune therapy and drug development.
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Enzymes are widely used in industry due to their high efficiency and selectivity. However, their low stability during certain industrial processes can result in a significant loss of catalytic activity. Encapsulation is a promising technique that can stabilize enzymes by protecting them from environmental stresses such as extreme temperature and pH, mechanical force, organic solvents, and proteases. Alginate and alginate-based materials have emerged as effective carriers for enzyme encapsulation due to their biocompatibility, biodegradability, and ability to form gel beads through ionic gelation. This review presents various alginate-based encapsulation systems for enzyme stabilization and explores their applications in different industries. We discuss the preparation methods of alginate encapsulated enzymes and analyze the release mechanisms of enzymes from alginate materials. Additionally, we summarize the characterization techniques used for enzyme-alginate composites. This review provides insights into the use of alginate encapsulation as a means of stabilizing enzymes and highlights the potential benefits for various industrial applications.
Assuntos
Alginatos , Enzimas Imobilizadas , Alginatos/química , Enzimas Imobilizadas/química , Fenômenos MecânicosRESUMO
Cell membrane-coated nanoparticles are emerging as a new type of promising nanomaterials for immune evasion and targeted delivery. An underlying premise is that the unique biological functions of natural cell membranes can be conferred on the inherent physiochemical properties of nanoparticles by coating them with a cell membrane. However, the extent to which the membrane protein properties are preserved on these nanoparticles and the consequent bio-nano interactions are largely unexplored. Here, we synthesized two mesenchymal stem cell (MSC) membrane-coated silica nanoparticles (MCSNs), which have similar sizes but distinctly different stiffness values (MPa and GPa). Unexpectedly, a much lower macrophage uptake, but much higher cancer cell uptake, was found with the soft MCSNs compared with the stiff MCSNs. Intriguingly, we discovered that the soft MCSNs enabled the forming of a more protein-rich membrane coating and that coating had a high content of the MSC chemokine CXCR4 and MSC surface marker CD90. This led to the soft MCSNs enhancing cancer cell uptake mediated by the CD90/integrin receptor-mediated pathway and CXCR4/SDF-1 pathways. These findings provide a major step forward in our fundamental understanding of how the combination of nanoparticle elasticity and membrane coating may be used to facilitate bio-nano interactions and pave the way forward in the development of more effective cancer nanomedicines.
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Nanopartículas , Neoplasias , Humanos , Membrana Celular/metabolismo , Nanopartículas/química , Proteínas/metabolismo , Neoplasias/metabolismo , ElasticidadeRESUMO
Förster resonance energy transfer (FRET) has been widely used for monitoring drug release from nanoparticles (NPs). To understand the drug release from bioinspired drug-core silica-shell NPs, we synthesised two types of NPs using the dual-functional peptide SurSi via biosilicification for the first time, i.e., silica NP conjugated with FRET (Cy3 and Cy5) molecules, and FRET-core (DiO and DiI) silica-shell NP with different shell thicknesses (18 and 41 nm). The release kinetics of these two types of NPs were investigated under different conditions, including fetal bovine serum (FBS) and in cells, to mimic the drug release during blood circulation and intracellularly. Two different drug release mechanisms were identified. Cargo diffusion dominated the release during circulation, while the degradation of silica shell played a key role in drug release intracellularly.
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Nanopartículas , Dióxido de Silício , Difusão , Liberação Controlada de Fármacos , Transferência Ressonante de Energia de Fluorescência , Nanopartículas/química , Dióxido de Silício/químicaRESUMO
Nanoparticles (NPs) have attracted tremendous interest in drug delivery in the past decades. Microfluidics offers a promising strategy for making NPs for drug delivery due to its capability in precisely controlling NP properties. The recent success of mRNA vaccines using microfluidics represents a big milestone for microfluidic NPs for pharmaceutical applications, and its rapid scaling up demonstrates the feasibility of using microfluidics for industrial-scale manufacturing. This article provides a critical review of recent progress in microfluidic NPs for drug delivery. First, the synthesis of organic NPs using microfluidics focusing on typical microfluidic methods and their applications in making popular and clinically relevant NPs, such as liposomes, lipid NPs, and polymer NPs, as well as their synthesis mechanisms are summarized. Then, the microfluidic synthesis of several representative inorganic NPs (e.g., silica, metal, metal oxide, and quantum dots), and hybrid NPs is discussed. Lastly, the applications of microfluidic NPs for various drug delivery applications are presented.
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Nanopartículas , Pontos Quânticos , Sistemas de Liberação de Medicamentos , Microfluídica , PolímerosRESUMO
As the education of students attracts more and more attention, the task of graduation development prediction has gradually become a hot topic in academia and industry. The task of graduation development prediction aims to predict the employment category of students in advance via academic achievement data, which can help administrators understand students' learning status and set up a reasonable learning plan. However, existing research ignores the potential impact of social relationships on students' graduation development choices. To fully explore social relationships among students, we propose a Social-path Embedding-based Transformer Neural Network (SPE-TNN) for the task of graduation development prediction in this paper. Specifically, SPE-TNN is divided into the Social-path selection layer, the Social-path embedding layer, the Transformer layer, and the Multi-layer projection layer. Firstly, the Social-path selection layer is designed to find social relationships that impact graduation development and embed them into the student's performance features through the Social-path embedding layer. Secondly, the Transformer layer is adopted to balance the weights of the students' features. Finally, the Multi-layer projection layer is used to achieve the student graduation development prediction. Experimental results on the real-world datasets show that SPE-TNN outperforms the existing popular approaches.
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A protein corona forms around nanoparticles when they are intravenously injected into the bloodstream. The composition of the protein corona dictates the interactions between nanoparticles and the biological systems thus their immune evasion, blood circulation, and biodistribution. Here, we report for the first time the impact of nanoparticle stiffness on protein corona formation using a unique emulsion core silica shell nanocapsules library with a wide range of mechanical properties over four magnitudes (700 kPa to 10 GPa). The nanocapsules with different stiffness showed distinct proteomic fingerprints. The protein corona of the stiffest nanocapsules contained the highest amount of complement protein (Complement C3) and immunoglobulin proteins, which contributed to their high macrophage uptake, confirming the important role of nanocapsules stiffness in controlling the protein corona formation thus their in vitro and in vivo behaviors.
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Nanopartículas , Coroa de Proteína , Adsorção , Proteômica , Distribuição TecidualRESUMO
Fluorescence labelling is often used for tracking nanoparticles, providing a convenient assay for monitoring nanoparticle drug delivery. However, it is difficult to be quantitative, as many factors affect the fluorescence intensity. Förster resonance energy transfer (FRET), taking advantage of the energy transfer from a donor fluorophore to an acceptor fluorophore, provides a distance ruler to probe NP drug delivery. This article provides a review of different FRET approaches for the ratiometric monitoring of the self-assembly and formation of nanoparticles, their in vivo fate, integrity and drug release. We anticipate that the fundamental understanding gained from these ratiometric studies will offer new insights into the design of new nanoparticles with improved and better-controlled properties.
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Nanopartículas , Preparações Farmacêuticas , Sistemas de Liberação de Medicamentos , Transferência Ressonante de Energia de Fluorescência , Corantes FluorescentesRESUMO
Common fragile sites (CFSs) are specific breakage-prone genomic regions and are present frequently in cancer cells. The (E2-independent) E3 ubiquitin-conjugating enzyme FATS (fragile site-associated tumor suppressor) has antitumor activity in cancer cells, but the function of FATS in immune cells is unknown. Here, we report a function of FATS in tumor development via regulation of tumor immunity. Fats-/- mice show reduced subcutaneous B16 melanoma and H7 pancreatic tumor growth compared with WT controls. The reduced tumor growth in Fats-/- mice is macrophage dependent and is associated with a phenotypic shift of macrophages within the tumor from tumor-promoting M2-like to antitumor M1-like macrophages. In addition, FATS deficiency promotes M1 polarization by stimulating and prolonging NF-κB activation by disrupting NF-κB/IκBα negative feedback loops and indirectly enhances both CD4+ T helper type 1 (Th1) and cytotoxic T lymphocyte (CTL) adaptive immune responses to promote tumor regression. Notably, transfer of Fats-/- macrophages protects mice against B16 melanoma. Together, these data suggest that FATS functions as an immune regulator and is a potential target in cancer immunotherapy.
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Proteínas de Ciclo Celular/imunologia , Macrófagos/imunologia , Neoplasias/imunologia , Proteínas Supressoras de Tumor/imunologia , Enzimas de Conjugação de Ubiquitina/imunologia , Animais , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Humanos , Imunoterapia , Ativação de Macrófagos , Camundongos , Inibidor de NF-kappaB alfa/metabolismo , NF-kappa B/metabolismo , Neoplasias/patologia , Neoplasias/terapia , Transdução de Sinais/imunologia , Linfócitos T Citotóxicos/imunologia , Células Th1/imunologia , Proteínas Supressoras de Tumor/genética , Enzimas de Conjugação de Ubiquitina/genéticaRESUMO
Labeling nanoparticles with fluorescent dyes is a common approach to investigate their cell uptake and biodistribution, providing valuable information for the preclinical assessment of nanoparticles for drug delivery. However, the underlying assumption that the fluorescence intensity of dye-labeled nanoparticles correlates positively with the amount of nanoparticles taken up by cells might not be valid under some conditions, as it can be affected by many factors including dye dispersion, dye quenching, and material shading. Here we demonstrated that both nanoparticles with hydrophobic dyes encapsulated inside and nanoparticles with hydrophilic dyes conjugated on the particle surface suffer from different degrees of dye quenching, making it challenging for quantitative comparison of cell uptake of different nanoparticles. To address this challenge, we proposed a possible solution for direct comparative studies of dye-labeled nanoparticles. This work provides valuable information for designing and evaluating different nanoparticles for drug delivery applications.
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Corantes Fluorescentes , Nanopartículas , Interações Hidrofóbicas e Hidrofílicas , Distribuição TecidualRESUMO
Pancreatic cancer is a highly malignant cancer of the digestive tract. Studies have shown that in some types of cancer, a high level of microRNA-194-5p (miR-194-5p) is beneficial for controlling tumor progression, while in other cancers it plays a completely opposite role. However, how miR-194-5p affects anti-tumor immunity of pancreatic cancer remains unclear. In this study, we found that high expression of miR-194-5p in human pancreatic cancer patients is associated with a better survival rate, while increased expression of programmed cell death ligand 1 (PD-L1) in human pancreatic cancer patients is associated with a worse survival rate. In pancreatic cancer, the expression level of PD-L1 is negatively correlated with the expression level of miR-194-5p, and we identified that PD-L1 was target gene of miR-194-5p. In addition, we found that overexpression of miR-194-5p inhibited the migration, invasion and proliferation of pancreatic cancer cells in vitro. The orthotopic mouse model of pancreatic cancer shown that miR-194-5p suppressed the progression of pancreatic cancer, promoted the infiltration of CD8+ T cells in tumor immune microenvironments, and enhanced the IFN-γ production of CD8+ T cells. Consistently, the co-culture experiments showed that overexpression of miR-194-5p in tumor cell enhanced IFN-γ production by CD8+ T cells. In conclusion, miR-194-5p may serve as a novel immunotherapeutic target for pancreatic ductal adenocarcinoma (PDAC) by inhibiting the expression of PD-L1, and play important roles in inhibiting the progression of pancreatic cancer and boosting the anti-tumor effect of CD8+ T cells.
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Antígeno B7-H1/genética , MicroRNAs/metabolismo , Neoplasias Pancreáticas/genética , Microambiente Tumoral/imunologia , Animais , Antígeno B7-H1/metabolismo , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linhagem Celular Tumoral , Conjuntos de Dados como Assunto , Regulação para Baixo/imunologia , Regulação Neoplásica da Expressão Gênica/imunologia , Células HEK293 , Humanos , Camundongos , Neoplasias Pancreáticas/imunologia , Neoplasias Pancreáticas/patologia , Evasão Tumoral/genética , Microambiente Tumoral/genéticaRESUMO
Polymer nanoparticles (NPs) have attracted significant interest in the past years for drug delivery and triggered release. However, it remains a significant challenge to produce polymer NPs with controlled properties and tunable drug loading. Traditional nanoprecipitation often leads to low drug loading. This study reports the development of a new microfluidic nanoprecipitation approach for making polymer NPs with tunable drug loading up to 50%. The synthesized curcumin-loaded shellac NPs remain very stable for the period of our experiments (10 days) under acidic conditions (pH 4.5), but release the payload at neutral pH in a sustained manner. This work provides a new strategy for making drug-loaded polymer NPs with tunable drug loading and triggered release.
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Curcumina , Nanopartículas , Preparações Farmacêuticas , Portadores de Fármacos , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Microfluídica , Tamanho da Partícula , PolímerosRESUMO
Biomimetic nanomaterials have attracted tremendous research interest in the past decade. We recently developed biomimetic core-shell nanoparticles - silica nanocapsules, using a designer dual-functional peptide SurSi under room temperature, neutral pH and without use of any toxic reagents or chemicals. The SurSi peptide is designed capable of not only stabilizing nanoemulsions because of its excellent surface activity, but also inducing the formation of silica through biosilicification at an oil-water interface. However, it remains challenging to precisely control the peptide-induced nucleation and biosilicification specifically at the oil-water interface, thus forming oil-core silica-shell nanocapsules with uniform size and monodispersity. In this study, the fundamental mechanism of silica formation through a peptide catalyzed biosilicification was systematically investigated, so that the formation of oil-core silica-shell nanocapsules can be precisely controlled. The SurSi peptide induced hydrolysis and nucleation of biomineralized silica particles were monitored to study the biosilicification kinetics. Effects of pH, SurSi peptide concentration and pre-hydrolysis of silica precursors were also studied to optimize the formation of biomimetic silica nanocapsules. The fundamental understanding achieved through these systematic studies provides valuable insights for making core-shell nanoparticles via controlling nucleation and reaction at interfaces.
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Nanocápsulas , Nanopartículas , Biomimética , Peptídeos , Dióxido de SilícioRESUMO
Acute peritonitis is an acute inflammatory response of the peritoneal cavity to physical injury and chemical stimulation. Timely resolution of this response is critical to prevent further damage to the body, which can eventually lead to more severe chronic inflammation. Arctigenin (ATG) is the main active ingredient of the Chinese medicine Arctium lappa. In recent years, there have been an increasing number of studies on the anti-inflammatory effect of ATG, but there have been few studies on the effect of ATG on acute inflammation, especially in acute peritonitis, which has not been reported. In this study, a mouse model of experimental acute peritonitis induced by thioglycolate (TG) solution was used to study the protective anti-inflammatory effect of ATG against acute peritonitis and the relevant mechanism. Our results showed that, after 12 hours of TG treatment, ATG significantly reduced inflammatory cell infiltration in mouse tissues and inhibited the secretion and expression of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in mice. ATG significantly reduced the percentage of CD11b+ Ly6G+ neutrophils and F4/80+ macrophages in the spleen and peritoneal exudate. In addition, ATG significantly inhibited the expression of the chemokines CCL3 and CCL4 and the adhesion molecule CD62L on the surface of CD11b-positive monocytes. ATG was observed to inhibit the phosphorylation of p65 and p38 in LPS-stimulated RAW264.7 cells. In conclusion, ATG can improve the symptoms of TG-induced acute peritonitis through immune regulation. ATG can reduce the inflammatory response in TG-induced acute peritonitis in mice.
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Anti-Inflamatórios/administração & dosagem , Furanos/administração & dosagem , Lignanas/administração & dosagem , Peritonite/tratamento farmacológico , Tioglicolatos/efeitos adversos , Animais , Anti-Inflamatórios/farmacologia , Quimiocinas/metabolismo , Modelos Animais de Doenças , Feminino , Furanos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Interleucina-6/metabolismo , Selectina L/metabolismo , Lignanas/farmacologia , Lipopolissacarídeos/efeitos adversos , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Camundongos , Neutrófilos/efeitos dos fármacos , Neutrófilos/imunologia , Peritonite/induzido quimicamente , Células RAW 264.7 , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Formulating drugs into nanoparticles offers many attractive advantages over free drugs including improved bioavailability, minimized toxic side effects, enhanced drug delivery, feasibility of incorporating other functions such as controlled release, imaging agents for imaging, targeting delivery, and loading more than one drug for combination therapies. One of the key parameters is drug loading, which is defined as the mass ratio of drug to drug-loaded nanoparticles. Currently, most nanoparticle systems have relatively low drug loading (<10â wt%), and developing methods to increase drug loading remains a challenge. This Minireview presents an overview of recent research on developing nanoparticles with high drug loading (>10â wt%) from the perspective of synthesis strategies, including post-loading, co-loading, and pre-loading. Based on these three different strategies, various nanoparticle systems with different materials and drugs are summarized and discussed in terms of their synthesis methods, drug loadings, encapsulation efficiencies, release profiles, stabilities, and their applications in drug delivery. The advantages and disadvantages of these strategies are presented with an objective of providing useful design rules for future development of high-drug-loading nanoparticles.
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Portadores de Fármacos , Nanopartículas/química , Composição de MedicamentosRESUMO
Understanding drug-release kinetics is critical for the development of drug-loaded nanoparticles. We developed a J-aggregate-based Förster-resonance energy-transfer (FRET) method to investigate the release of novel high-drug-loading (50â wt %) nanoparticles in comparison with low-drug-loading (0.5â wt %) nanoparticles. Single-dye-loaded nanoparticles form J-aggregates because of the high dye-loading (50â wt %), resulting in a large red-shift (≈110â nm) in the fluorescence spectrum. Dual-dye-loaded nanoparticles with high dye-loading using FRET pairs exhibited not only FRET but also a J-aggregate red-shift (116â nm). Using this J-aggregate-based FRET method, dye-core-polymer-shell nanoparticles showed two release processes intracellularly: the dissolution of the dye aggregates into dye molecules and the release of the dye molecules from the polymer shell. Also, the high-dye-loading nanoparticles (50â wt %) exhibited a slow release kinetics in serum and relatively quick release in cells, demonstrating their great potential in drug delivery.
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Portadores de Fármacos/química , Transferência Ressonante de Energia de Fluorescência/métodos , Nanopartículas/química , Polímeros/química , Liberação Controlada de Fármacos , Microscopia Eletrônica de TransmissãoRESUMO
Pancreatic adenocarcinoma (PDAC) is a highly fatal disease worldwide. MicroRNAs (miRNAs) could regulate the protein-coding RNAs related to tumor growth, invasion, and immune evasion. Therefore, the investigation of novel miRNAs may be helpful in the development of more effective therapies for PDAC. In this study, we investigated the role and mechanism of action of miR-128 in PDAC. By using bioinformatics methods, we found that decreased expression of miR-128 was associated with poor overall survival of PDAC. miR-128 was inversely correlated with cluster of differentiation 47 (CD47), which was positively related to zinc finger E-box-binding homeobox 1 (ZEB1) in PDAC. Through in vivo experiments, we found that miR-128 could suppress the growth and metastasis of PDAC. Analysis of the immune microenvironment demonstrated that overexpression of miR-128 on tumor cells could increase the percentages of dendritic cells (DCs), CD8+ T lymphocytes, and natural killer T cells (NKT) in the tumor and spleen, consequently enhancing anti-tumor immunity. In vitro assays showed that miR-128 could inhibit cell proliferation, clonogenicity, migration, and invasion in Panc02 cells and could also enhance the phagocytosis of macrophages and the activity of DCs. Western blot and qRT-PCR confirmed that miR-128 could regulate ZEB1 and further inhibit CD47 in pancreatic cancer cells. Therefore, we identified a novel regulatory anti-tumor mechanism by miR-128 in PDAC, which may serve as a novel therapy for PDAC.
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Antígeno CD47/metabolismo , Carcinoma Ductal Pancreático/metabolismo , Citotoxicidade Imunológica , Linfócitos do Interstício Tumoral/metabolismo , MicroRNAs/metabolismo , Neoplasias Pancreáticas/metabolismo , Microambiente Tumoral , Animais , Antígeno CD47/genética , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/imunologia , Carcinoma Ductal Pancreático/secundário , Linhagem Celular Tumoral , Bases de Dados Genéticas , Regulação Neoplásica da Expressão Gênica , Humanos , Linfócitos do Interstício Tumoral/imunologia , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/imunologia , Neoplasias Pancreáticas/patologia , Prognóstico , Transdução de Sinais , Carga Tumoral , Homeobox 1 de Ligação a E-box em Dedo de Zinco/genética , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismoRESUMO
BACKGROUND: Immune checkpoint blockade has emerged as a potential cancer immunotherapy. The "don't eat me" signal CD47 in cancer cells binds signal regulatory protein-α on macrophages and prevents their phagocytosis. The role of miR-340 in pancreatic ductal adenocarcinoma (PDAC), especially in tumor immunity, has not been explored. Here, we examined the clinical and biological relevance of miR-340 and the molecular pathways regulated by miR-340 in PDAC. METHODS: CD47 and miR-340 expression and the relationship with cancer patient survival were analyzed by bioinformatics. The mechanism of miR-340 action was explored through bioinformatics, luciferase reporter, qRT-PCR and western blot analyses. The effects of miR-340 on cancer cells were analyzed in terms of apoptosis, proliferation, migration and phagocytosis by macrophages. In vivo tumorigenesis was studied in orthotopic and subcutaneous models, and immune cells from the peripheral and tumor immune microenvironments were analyzed by flow cytometry. Depletion of macrophages was used to verify the role of macrophages in impacting the function of miR-340 in tumor progression. RESULTS: miR-340 directly regulates and inversely correlates with CD47, and it predicts patient survival in PDAC. The restoration of miR-340 expression in pancreatic cancer cells was sufficient to downregulate CD47 and promote phagocytosis of macrophages, further inhibiting tumor growth. The overexpression of miR-340 promoted macrophages to become M1-like phenotype polarized in peripheral and tumor immune microenvironments and increased T cells, especially CD8+ T cells, contributing to the antitumor effect of miR-340. CONCLUSIONS: miR-340 is a key regulator of phagocytosis and antitumor immunity, and it could offer a new opportunity for immunotherapy for PDAC.
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Antígeno CD47/metabolismo , Carcinoma Ductal Pancreático/imunologia , Macrófagos/imunologia , MicroRNAs/genética , Neoplasias Pancreáticas/imunologia , Fagocitose , Microambiente Tumoral/imunologia , Animais , Apoptose , Antígeno CD47/genética , Antígeno CD47/imunologia , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/terapia , Proliferação de Células , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/terapia , Prognóstico , Taxa de Sobrevida , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Under suboxic and anoxic environments, magnetite is one corrosion product of iron being used in nuclear waste canisters. Previous studies have reported a complete reduction of U(VI) on the surfaces of biogenic and natural magnetite crystals, while incomplete reductions to U(V)/U(IV)-containing species have been observed on chemosynthetic magnetite. To date, the reasons behind such disparities remain poorly studied. This study shows that uranyl nitrate or uranyl acetate is mainly reduced to UO2+x oxides (e.g., U4O9, U3O8, etc.) by chemosynthetic magnetite under acidic conditions. When extra zero valent-iron was added, the reaction rate was significantly increased, and an improved but still incomplete U(VI) reduction was observed. Nitrate and ferric ions are ubiquitous in natural environment. Results demonstrate that the nitrate ion associated with uranyl and the ferric ion contained in magnetite or generated from U(VI) reduction have a non-negligible oxidative effect on the final products, which could mainly account for the incomplete reduction of U(VI) by chemosynthetic magnetite in the absence or presence of extra zero valent-iron observed in this study. Furthermore, the surface loading of uranium in U-Fe systems can, in part, unravel the discrepancies in various observations. An enhanced understanding of the U-Fe reaction mechanism can facilitate predictions of the extent of uranium mobility with respect to nuclear waste disposal and radioactive decontamination.
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Óxido Ferroso-Férrico/química , Urânio/química , Poluentes Radioativos da Água/química , Ferro/química , Nitratos , Compostos Organometálicos , Oxirredução , Resíduos Radioativos , Nitrato de Uranil , Poluentes Radioativos da Água/análiseRESUMO
Biomineralization of metal organic frameworks (MOFs) using biomolecules has recently attracted significant interest because of the benign process including room temperature, neutral pH and without the requirement of any other chemical reagents. Also, these biomolecule incorporated MOFs (biomolecules@MOFs) have demonstrated their potential in biomolecule encapsulation, protection and controlled release. This work aims to develop a general strategy to make biomolecules@MOFs via a biomimetic mineralization process. A library of biomolecules (peptides and proteins) with different charges were systematically studied to fundamentally understand the role of biomolecules and their proprieties in biomolecule-mediated MOF biomineralization. Biomolecule charge, amino acid sequence and stirring speed have been demonstrated to play important roles in controlling biomineralization reaction rate, particle shape and morphology.