Nanotechnology approaches in the current therapy of skin cancer

Skin cancer is a high burden disease with a high impact on global health. Conventional therapies have several drawbacks; thus, the development of effective therapies is required. In this context, nanotechnology approaches are an attractive strategy for cancer therapy because they enable the efficient delivery of drugs and other bioactive molecules to target tissues with low toxic effects. In this review, nanotechnological tools for skin cancer will be summarized and discussed. First, pathology and conventional therapies will be presented, followed by the challenges of skin cancer therapy. Then, the main features of developing efficient nanosystems will be discussed, and next, the most commonly used nanoparticles (NPs) described in the literature for skin cancer therapy will be presented. Subsequently, the use of NPs to deliver chemotherapeutics, immune and vaccine molecules and nucleic acids will be reviewed and discussed as will the combination of physical methods and NPs. Finally, multifunctional delivery systems to codeliver anticancer therapeutic agents containing or not surface functionalization will be summarized

Givinostat-Liposomes: Anti-Tumor Effect on 2D and 3D Glioblastoma Models and Pharmacokinetics

Glioblastoma is the most common and aggressive brain tumor, associated with poor prognosis and survival, representing a challenging medical issue for neurooncologists. Dysregulation of histone-modifying enzymes (HDACs) is commonly identified in many tumors and has been linked to cancer proliferation, changes in metabolism, and drug resistance. These findings led to the development of HDAC inhibitors, which are limited by their narrow therapeutic index. In this work, we provide the proof of concept for a delivery system that can improve the in vivo half-life and increase the brain delivery of Givinostat, a pan-HDAC inhibitor. Here, 150-nm-sized liposomes composed of cholesterol and sphingomyelin with or without surface decoration with mApoE peptide, inhibited human glioblastoma cell growth in 2D and 3D models by inducing a time-and dose-dependent reduction in cell viability, reduction in the receptors involved in cholesterol metabolism (from −25% to −75% of protein levels), and reduction in HDAC activity (−25% within 30 min). In addition, liposome-Givinostat formulations showed a 2.5-fold increase in the drug half-life in the bloodstream and a 6-fold increase in the amount of drug entering the brain in healthy mice, without any signs of overt toxicity. These features make liposomes loaded with Givinostat valuable as potential candidates for glioblastoma therapy

Dodecylated and non-dodecylated poly(succinimide)-based polyplexes with pEGFP-N3 plasmid: polymer synthesis, plasmid transfection and GFP expression.

O uso de genes em terapias é um conceito originado em 1970 em consequência do crescimento exponencial de novas tecnologias para liberação de DNA, também pela capacidade de expressão de genes exógenos em células de mamíferos. Propomos, então, a síntese de polímeros catiônicos, em dois grupos, por meio da aminólise da poli(succinimida) (PSI): grupo 1An, polímeros catiônicos com arcabouço poli (ácido aspártico) com cadeias laterais contendo aminas protonáveis; grupo 2An, polímeros catiônicos anfifílicos, contenho o poli (ácido aspártico) como arcabouço, com aminas protonáveis e cadeias dodecilamina. Estudos de SEC mostraram que derivados dodecilados 2An tiveram tamanho menor que os polímeros do grupo 1An, não dodecilados. A capacidade tamponante para todos os polímeros sintetizados foi maior que o bPEI 25, e o grupo 2An apresentou as maiores capacidades tamponantes. Derivados 2An com as aminas A1 a A4 apresentaram menor CMC do que o grupo 1An. Citotoxicidade dos policátions foi dependente das suas concentrações e, entre todos os polímeros, aqueles com aminas A5 e A6 não foram citotóxicos. A presença da cadeia dodecilamina na PSI não diminuiu a viabilidade celular até 250 ?L-1, sugerindo que a porção hidrofóbica não é citotóxica na faixa de concentrações testada. A complexação do pEGFP-N3 com os derivados de PSI foi realizada, bem como a transfecção dos poliplexos em células HeLa. A expressão de GFP dos complexos obtidos com bPEI 25 foi quantificada e comparada com os poliplexos preparados com os derivados da PSI. Ensaios de transfecção mostraram que os derivados dodecilados da PSI apresentaram expressão negligenciável de GFP em células HeLa, sugerindo uma ligação forte entre plasmídeo e os derivados sintetizados e não-liberação do material genético nas células, ou dano celular causado pela cadeia hidrofóbica nas células. Os maiores valores de GFP quantificados foram encontrados nos poliplexos contendo polímeros não-dodecilados e com as aminas A3 e A4, nas razoes N:P 5 a 20 para A3 e N:P 5 para A4. Ambas as estruturas A3 e A4 fazem parte do core do bPEI 25.Genes as drugs for human therapy is a concept originally conceived around 1970, a consequence of the exponential growth in knowledge of human gene function, the more effective technologies for DNA delivery, and the ability to transfer and express exogenous genes in mammalian cells. Here we propose synthesizing two small library groups of cationic polymers via aminolysis of poly(succinimide) (PSI) backbone: group 1An, polycationic polymers with a degradable amide of poly(aspartic) acid backbone, protonable oligoamine side chains into the main polymer structure, and group 2An, amphiphilic cationic polymers with a degradable amide of poly(aspartic) acid backbone, protonable oligoamine side chains into the main polymer structure and dodecyl side chain moieties. SEC showed that dodecylated derivatives 2An had lower size than 1An group, non-dodecylated polyelectrolytes. Buffering capacity of all synthesized polymers was higher than the standard bPEI 25, and the dodecylated 2An group had the highest buffering capacities values. 2An derivatives with amines A1 to A4 showed lower CMC than their non-dodecylated pairs. Cytotoxicity of all polycations was dependent on the concentrations, and among all polymers, those with amines A5 and A6 had lower cytotoxicity than bPEI 25. Moreover, the presence of the hydrophobic dodecyl side chain in the PSI backbone did not decrease the cell viability until 250 ?g mL-1 polymer concentration, thus suggesting the hydrophobic moiety is not cytotoxic in this range. Complexation of pEGFP-N3 plasmid with PSI derivatives grafted with amines A1 to A4 was performed, as well as the transfection of polyplexes into HeLa cells. GFP expression of bPEI25 polyplexes in different complex volumes was quantified and compared with PSI derivatives/pEGFP-N3 polyplexes. Transfection assays showed that dodecylated PSI derivatives had negligible or no GFP expression in HeLa cells, thus suggesting a strong interaction between polycations and pDNA or a cellular damage caused by the hydrophobic moiety, although cytotoxicity assay of polyplexes showed low cytotoxicity of polyplexes. The highest GFP expression values were found for polycations 1A3 and 1A4, both without the dodecylamine side chain, in the N:P ratios 5 to 20 for 1A3, and N:P ratio 5 for 1A4. Both amines A3 and A4 used for the PSI grafting are core structures of bPEI 25

Preparation and characterization of membranes obtained by silk fibroin and poly(vinyl alcohol)

A fibroína da seda (SF) é uma proteína fibrosa, com caráter hidrofóbico, produzida pelo bicho-da-seda (Bombyx mori L.), cuja produção e armazenamento ocorre em glândulas especializadas antes do processo de fiação em fibras. Recentemente, soluções de fibroína de seda regenerada (RSF) têm sido utilizadas para formar diferentes materiais tais como géis, membranas, filmes e esponjas, para aplicações médicas (Medicina Regenerativa) e em sistemas de liberação de fármacos. Neste trabalho, procuramos estudar o comportamento da solução RSF 2% com adição de 0,25, 0,5 e 1% de PVA (polímero sintético e hidrofílico) por meio de ensaios de reologia dos géis obtidos (SF:PVA), e caracterização das membranas obtidas por meio da secagem em moldes dos géis. Os ensaios de reologia mostraram uma inversão de módulos, com transição de caráter elástico (G\') para viscoso (G\") para SF1 a 3%, entre 230 e 900% de deformação (\'gama\'); transição de caráter viscoso para elástico para as blendas SF:PVA 0,5 e 1% em ensaio de frequência (\'ômega\'). Com o aumento de temperatura, todas as blendas mantiveram seus comportamentos elástico (SF:PVA 0,25%) e viscoso (SF:PVA 0,5 e 1%) até 49 - 51°C, com transição líquido-gel; o aumento dos módulos G\' e G\"com o resfriamento das amostras ocorreu em todas as blendas. As membranas obtidas das blendas SF:PVA tiveram maior absorção de tampão fosfato salino (PBS) após 5 min de ensaio, no qual a blenda SF:PVA apresentou maiores valores de absorção. A caracterização das membranas por FT-IR ATR e DRX mostrou que ocorreu uma transição de conformação aleatória e hélice \'alfa\' para folha \'beta\', para todas as membranas, indicando que a adição do PVA nas blendas promoveu transições silk I para silk II. Deslocamentos de modo vibracional de 1.637/cm (amida I) para 1.616/cm (amida I) com modo centrado em 1.512/cm (amida II) foram vistos em todas as blendas no FT-IR ATR, e difratogramas apresentaram picos característicos às estruturas silk I (2\'teta\' = 10,12º, 2\'teta\' = 12,2° e 2\'teta\' = 28,2º) e silk II (2\'teta\' = 20 - 21 °1). TGA e DSC mostraram uma interação entre as cadeias de RSF c PVA, pela presença de uma temperatura única ele transição vítrea (Tg) entre RSF e PVA. Imagens AFM das blendas mostraram a presença de estruturas nanofibrilares, em formato de ilhas compactas e ramos, confirmando a transição da fase amorfa de SF 2% para hélice \'alfa\' e folha \'beta\', com a adição do PVA.Silk fibroin (SF) is a fibrous hydrophobic protein produced by silkworms (Bombyx mori L.), which production and storage occur into specialized glands previously fiber formation. Lately, regenerated silk fibroin (RSF) solutions have been used to produce different materials such as gels, membranes, films and sponges, for medical applications and drug delivery systems. In this study, the RSF with 0.25, 0.5 anel 1% PVA (synthetic and hydrophilic polymer) blends were characterized by rheological tests of the gels (SF:PVA), also membranes produced by casting process were characterized as well. Rheological tests showed moduli inversion with elastic to viscous behavior transition for SF 1 to 3%, between 230 anel 900% of strain (\'gama\'); a transition fram viscous to elastic behavior to SF:PVA 0.5 to 1% blends into frequency sweep tests was observed. With the temperature increment, all blends have kept their viscous anel elastic behavior until 49 - 51°C, and a liquid-gel transition occurred in the SF:PVA 0.5 and 1% blends, as well as all moduli have increased with the cooling stage of the samples. All membranes had the highest buffer absorption after 5 min of test, in which SF:PVA 0.5% blend presented high absorption values. FT-IR spectra and XRD diffractograms showed a transition from random and \'alfa\'-helix to \'beta\'-sheet, for all blends, indicating that PVA addition promotes silk I to silk II transition. Modal shifts were observed from 1.637/cm (amide I) to 1.616/cm (amide I) with a central mode in 1.512/cm (amide II) in all blends in the FT-IR ATR spectra. XRD diffractograms showed characteristic peaks of silk I structures (2\'teta\' = 10,12°, 2\'teta\' = 12,2° e 2\'teta\' = 28,2°) and silk II structures (2\'teta\' = 20 - 21 °1). TGA and DSC studies showed the possibility of interaction between SF and PVA chains by acquirement of mobility at once, at an intermediate temperature between SF anel PVA glass transition (Tg). AFM images exhibited different phases for all membranes, with the presence of nanofibers, wires, rods and branch islands, suggesting the formation of more organized structures, such as and \'alfa\'-helix and \'beta\'-sheet, with PVA addition

Influence of Alkyl Chains of Modified Polysuccinimide‐Based Polycationic Polymers on Polyplex Formation and Transfection

The development of polymers with low toxicity and efficient gene delivery remains a significant barrier of nonviral gene therapy. Modification and tuning of chemical structures of carriers is an attractive strategy for efficient nucleic acid delivery. Here, polyplexes consisting of plasmid DNA (pDNA) and dodecylated or non-dodecylated polysuccinimide (PSI)-based polycations are designed, and their transfection ability into HeLa cells is investigated by green fluorescent protein (GFP) expressing cells quantification. All cationic polymers show lower cytotoxicity than those of branched polyethyleneimine (bPEI). PSI and bPEI-based polyplexes have comparable physicochemical properties such as size and charge. Interestingly, a strong interaction between dodecylated polycations and pDNA caused by the hydrophobic moiety is observed in dodecylated PSI derivatives. Moreover, the decrease of GFP expression is associated with lower dissociation of pDNA from polyplexes according to the heparin displacement assay. Besides, a hydrophobization of PSI cationic derivatives with dodecyl side chains can modulate the integrity of polyplexes by hydrophobic interactions, increasing the binding between the polymer and the DNA. These results provide useful information for designing polyplexes with lower toxicity and greater stability and transfection performance.This work was developed within the framework of National Institute of Science and Technology of Pharmaceutical Nanotechnology (INCT-Nanofarma), which is supported by "Fundacao de Amparo a Pesquisa do Estado de Sao Paulo" (FAPESP, Brazil, Grant #14/14/50928-2) and "Conselho Nacional de Pesquisa" (CNPQ, Brazil, Grant #465687/2014-8). M.H.K. was the recipient of a CAPES and DAAD scholarship. Technical support by University of Sao Paulo and Freie Universitat Berlin is acknowledged

Reduced Levels of ABCA1 Transporter Are Responsible for the Cholesterol Efflux Impairment in β-Amyloid-Induced Reactive Astrocytes: Potential Rescue from Biomimetic HDLs

The cerebral synthesis of cholesterol is mainly handled by astrocytes, which are also responsible for apoproteins’ synthesis and lipoproteins’ assembly required for the cholesterol transport in the brain parenchyma. In Alzheimer disease (AD), these processes are impaired, likely because of the astrogliosis, a process characterized by morphological and functional changes in astrocytes. Several ATP-binding cassette transporters expressed by brain cells are involved in the formation of nascent discoidal lipoproteins, but the effect of beta-amyloid (Aβ) assemblies on this process is not fully understood. In this study, we investigated how of Aβ1-42-induced astrogliosis affects the metabolism of cholesterol in vitro. We detected an impairment in the cholesterol efflux of reactive astrocytes attributable to reduced levels of ABCA1 transporters that could explain the decreased lipoproteins’ levels detected in AD patients. To approach this issue, we designed biomimetic HDLs and evaluated their performance as cholesterol acceptors. The results demonstrated the ability of apoA-I nanodiscs to cross the blood–brain barrier in vitro and to promote the cholesterol efflux from astrocytes, making them suitable as a potential supportive treatment for AD to compensate the depletion of cerebral HDLs

<i>In Vitro</i> Biocompatibility and Endothelial Permeability of Branched Polyglycidols Generated by Ring-Opening Polymerization of Glycidol with B(C₆F₅)₃ under Dry and Wet Conditions

Polyglycidol or polyglycerol (PG), a polyether widely used in biomedical applications, has not been extensively studied in its branched cyclic form (bcPG), despite extensive research on hyperbranched PG (HPG). This study explores the biomedical promise of bcPG, particularly its ability to cross the blood–brain barrier (BBB). We evaluate in vitro biocompatibility, endothelial permeability, and formation of branched linear PG (blPG) as topological impurities in the presence of water. Small angle X-ray scattering in solution revealed a fractal dimension of approximately two for bcPG and the mixture bc+blPG, suggesting random branching. Comparisons of cytotoxicity and endothelial permeability between bcPG, bc+blPG, and HPG in a BBB model using hCMEC/D3 cells showed different biocompatibility profiles and higher endothelial permeability for HPG. bcPG showed a tendency to accumulate around cell nuclei, in contrast to the behavior of HPG. This study contributes to the understanding of the influence of polymer topology on biological behavior