Tuning the endocytosis mechanism of Zr-based metal−organic frameworks through linker functionalization

A critical bottleneck for the use of metal-organic frameworks (MOFs) as drug delivery systems has been allowing them to reach their intracellular targets without being degraded in the acidic environment of the lysosomes. Cells take up particles by endocytosis through multiple biochemical pathways, and the fate of these particles depends on these routes of entry. Here, we show the effect of functional group incorporation into a series of Zr-based MOFs on their endocytosis mechanisms, allowing us to design an effi-cient drug delivery system. In particular, naphthalene-2,6-dicarboxylic acid and 4,4'-biphenyldicarboxylic acid ligands promote entry through the caveolin-pathway, allowing the particles to avoid lysosomal degradation and be delivered into the cytosol, en-hancing their therapeutic activity when loaded with drugs

Selective Surface PEGylation of UiO-66 Nanoparticles for Enhanced Stability, Cell Uptake, and pH-Responsive Drug Delivery.

The high storage capacities and excellent biocompatibilities of metal-organic frameworks (MOFs) have made them emerging candidates as drug-delivery vectors. Incorporation of surface functionality is a route to enhanced properties, and here we report on a surface-modification procedure-click modulation-that controls their size and surface chemistry. The zirconium terephthalate MOF UiO-66 is (1) synthesized as ∼200 nm nanoparticles coated with functionalized modulators, (2) loaded with cargo, and (3) covalently surface modified with poly(ethylene glycol) (PEG) chains through mild bioconjugate reactions. At pH 7.4, the PEG chains endow the MOF with enhanced stability toward phosphates and overcome the "burst release" phenomenon by blocking interaction with the exterior of the nanoparticles, whereas at pH 5.5, stimuli-responsive drug release is achieved. The mode of cellular internalization is also tuned by nanoparticle surface chemistry, such that PEGylated UiO-66 potentially escapes lysosomal degradation through enhanced caveolae-mediated uptake. This makes it a highly promising vector, as demonstrated for dichloroacetic-acid-loaded materials, which exhibit enhanced cytotoxicity. The versatility of the click modulation protocol will allow a wide range of MOFs to be easily surface functionalized for a number of applications

Mechanistic investigation into the selective anticancer cytotoxicity and immune system response of surface-functionalised, dichloroacetate-loaded, UiO-66 nanoparticles

The high drug loading and excellent biocompatibilities of metal-organic frameworks (MOFs) have led to their application as drug delivery systems (DDSs). Nanoparticle surface chemistry dominates both biostability and dispersion of DDSs while governing their interactions with biological systems, cellular and/or tissue targeting, and cellular internalisation, leading to a requirement for versatile and reproducible surface functionalisation protocols. Herein, we explore not only the effect of introducing different surface functionality to the biocompatible Zr-MOF UiO-66, but also the efficacy of three surface modification protocols: (i) direct attachment of biomolecules (folic acid, biotin) introduced as modulators of UiO-66 synthetic, (ii) our previously reported ‘’click-modulation” approach to covalently attach polymers (poly(ethylene glycol), poly-L-lactide, poly-N-isopropylacrylamide) to the surface of UiO-66 through click chemistry, and (iii) surface ligand exchange, to postsynthetically coordinate folic acid, biotin and heparin to UiO-66. The innovative use of a small molecule with metabolic anticancer activity, dichloroacetic acid (DCA), as a modulator during synthesis is described, and found to be compatible with all three protocols, yielding surface-coated, DCA-loaded (10-20% w/w) nanoMOFs (70-170 nm). External surface modification generally enhances stability and colloidal dispersion of UiO-66. Cellular internalisation routes and efficiencies of UiO-66 by HeLa cervical cancer cells can be tuned by surface chemistry, and anticancer cytotoxicity of DCA-loaded MOFs correlates with endocytosis efficiency and mechanisms. The MOFs with the most promising coatings (folic acid, poly(ethylene glycol), poly-L-lactide, and poly-N-isopropylacrylamide) were extensively tested for selectivity of anti-cancer cytotoxicity against MCF-7 breast cancer cells and HEK293 healthy kidney cells, as well as for cell proliferation and ROS production against J774 macrophages and peripheral blood lymphocytes (PBLs) isolated from the blood of human donors. DCA-loaded, folic acid modified UiO-66 selectively kills cancer cells without harming healthy ones or provoking immune system response in vitro, suggesting a significant targeting effect and great potential in anticancer drug delivery. The results provide mechanistic insight into the design and functionalisation of MOFs for drug delivery, and underline the availability of various in vitro techniques to potentially minimise early-stage in vivo animal studies, following the three Rs: reduction, refinement and replacement

A Combination of Approved Antibodies Overcomes Resistance of Lung Cancer to Osimertinib by Blocking Bypass Pathways.

<b>Purpose:</b> Because of emergence of resistance to osimertinib, a third-generation EGFR tyrosine kinase inhibitor (TKI), no targeted treatments are available for patients with lung cancer who lose sensitivity due to new mutations or bypass mechanisms. We examined in animals and <i>in vitro</i> an alternative therapeutic approach making use of antibodies. <b>Experimental Design:</b> An osimertinib-sensitive animal model of lung cancer, which rapidly develops drug resistance, has been employed. To overcome compensatory hyperactivation of ERK, which we previously reported, an anti-EGFR antibody (cetuximab) was combined with other antibodies, as well as with a subtherapeutic dose of osimertinib, and cancer cell apoptosis was assayed. <b>Results:</b> Our animal studies identified a combination of three clinically approved drugs, cetuximab, trastuzumab (an anti-HER2 mAb), and osimertinib (low dose), as an effective and long-lasting treatment that is able to prevent onset of resistance to osimertinib. A continuous schedule of concurrent treatment was sufficient for effective tumor inhibition and for prevention of relapses. Studies employing cultured cells and analyses of tumor extracts indicated that the combination of two mAbs and a subtherapeutic TKI dose sorted EGFR and HER2 for degradation; cooperatively enhanced apoptosis; inhibited activation of ERK; and reduced abundance of several bypass proteins, namely MET, AXL, and HER3. <b>Conclusions:</b> Our <i>in vitro</i> assays and animal studies identified an effective combination of clinically approved drugs that might overcome resistance to irreversible TKIs in clinical settings. The results we present attribute the long-lasting effect of the drug combination to simultaneous blockade of several well-characterized mechanisms of drug resistance. <i>Clin Cancer Res; 24(22); 5610-21. ©2018 AACR</i> <i>See related commentary by Fan and Yu, p. 5499</i>

Surface-functionalisation of Zr-Fumarate MOF for selective cytotoxicity and immune system compatibility in nanoscale drug delivery

Metal-organic frameworks (MOFs), network structures wherein metal ions or clusters link organic ligands into porous materials, are being actively researched as nanoscale drug delivery devices (DDSs) as they offer tuneable structures with high cargo loading that can easily be further functionalized for targeting and enhanced physiological stability. The excellent biocompatibility of Zr has meant that its MOFs are amongst the most studied to date, in particular the archetypal Zr terephthalate UiO-66. In contrast, the isoreticular analogue linked by fumarate (Zr-fum) has received little attention, despite the endogenous linker being part of the Krebs cycle. Herein, we report a comprehensive study of Zr-fum in the context of drug delivery. Reducing particle size is shown to increase uptake by cancer cells while reducing internalisation by macrophages, immune system cells that remove foreign objects from the bloodstream. Zr-fum is compatible with defect-loading of the drug dichloroacetate, as well as surface modification during synthesis, through coordination modulation, and postsynthetically. DCA-loaded, PEGylated Zr-fum shows selective in vitro cytotoxicity towards HeLa and MCF-7 cancer cells, likely as a consequence of its enhanced caveolae-mediated endocytosis compared to uncoated precursors, and it is well tolerated by HEK293 kidney cells, J774 macrophages, and human peripheral blood lymphocytes. Compared to UiO-66, Zr-fum is more efficient at transporting the drug mimic calcein into HeLa cells, and DCA-loaded, PEGylated Zr-fum is more effective at reducing HeLa and MCF-7 cell proliferation than the analogous UiO-66 sample. In vitro examination of immune system response shows Zr-fum samples induce less reactive oxygen species than UiO-66 analogues, possibly as a consequence of the linker being endogenous, and do not activate the C3 and C4 complement cascade pathways, suggesting that Zr-fum can avoid phagocytic activation. The results show that Zr-fum is an attractive alternative to UiO-66 for nanoscale drug delivery, and that a wide range of in vitro experiments are available to greatly inform the design of DDSs prior to early stage animal studies

Design of a Functionalized Metal-Organic Framework System for Enhanced Targeted Delivery to Mitochondria.

Mitochondria play a key role in oncogenesis and constitute one of the most important targets for cancer treatments. Although the most effective way to deliver drugs to mitochondria is by covalently linking them to a lipophilic cation, the in vivo delivery of free drugs still constitutes a critical bottleneck. Herein, we report the design of a mitochondria-targeted metal-organic framework (MOF) that greatly increases the efficacy of a model cancer drug, reducing the required dose to less than 1% compared to the free drug and ca. 10% compared to the nontargeted MOF. The performance of the system is evaluated using a holistic approach ranging from microscopy to transcriptomics. Super-resolution microscopy of MCF-7 cells treated with the targeted MOF system reveals important mitochondrial morphology changes that are clearly associated with cell death as soon as 30 min after incubation. Whole transcriptome analysis of cells indicates widespread changes in gene expression when treated with the MOF system, specifically in biological processes that have a profound effect on cell physiology and that are related to cell death. We show how targeting MOFs toward mitochondria represents a valuable strategy for the development of new drug delivery systems

Aplicativo móvel para recomendação de adubação e calagem para produção de mandioca no Amazonas.

Em decorrência da necessidade de elevar a produção de mandioca no Amazonas e ao difícil acesso dos produtores rurais às informações de manejo e cultivo, foi proposto e desenvolvido um aplicativo para smartphone com a plataforma Android, que tem como objetivo fornecer recomendação de adubação e calagem para correção do solo a partir do resultado da análise química realizada. Fornece ainda dicas práticas para manejo e cultivo da mandioca e ferramentas de cálculos e conversões necessárias para um bom planejamento e execução para um plantio de qualidade

Aplicativo móvel para auxiliar ações de transferência de tecnologia de citros no Amazonas.

No Estado do Amazonas, os solos apresentam baixa disponibilidade nutricional, o que acarreta baixa rentabilidade e consequente diminuição na produção. Grande parte dos pequenos agricultores não segue as recomendações disponibilizadas na literatura, inviabilizando sua plantação e trazendo prejuízos financeiros. Além disso, a produção de citros no Estado é insuficiente para suprir o mercado local. Com base nesse cenário, foi desenvolvido um aplicativo para rodar em smartphones e tablets que usem o sistema operacional Google Android, com o objetivo de auxiliar ações de transferência de tecnologia. O aplicativo possui funcionalidades de interpretação do solo a partir de análise química e fornecimento de dicas para uma efetiva produção de citros no Amazonas, ajudando os produtores a evitar desequilíbrios nutricionais, desperdícios de corretivos e consequentemente reduções na produtividade

Effect of chitosan essential oil films on the storage-keeping quality of pork meat products

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