Mannosylated Polycations Target CD206+ Antigen-Presenting Cells and Mediate T-Cell-Specific Activation in Cancer Vaccination.

Immunotherapy is deemed one of the most powerful therapeutic approaches to treat cancer. However, limited response and tumor specificity are still major challenges to address. Herein, mannosylated polycations targeting mannose receptor- are developed as vectors for plasmid DNA (pDNA)-based vaccines to improve selective delivery of genetic material to antigen-presenting cells and enhance immune cell activation. Three diblock glycopolycations (M15A12, M29A25, and M58A45) and two triblock copolymers (M29A29B9 and M62A52B32) are generated by using mannose (M), agmatine (A), and butyl (B) derivatives to target CD206, complex nucleic acids, and favor the endosomal escape, respectively. All glycopolycations efficiently complex pDNA at N/P ratios <5, protecting the pDNA from degradation in a physiological milieu. M58A45 and M62A52B32 complexed with plasmid encoding for antigenic ovalbumin (pOVA) trigger the immune activation of cultured dendritic cells, which present the SIINFEKL antigenic peptide via specific major histocompatibility complex-I. Importantly, administration of M58A45/pOVA elicits SIINFEKL-specific T-cell response in C56BL/6 mice bearing the melanoma tumor model B16-OVA, well in line with a reduction in tumor growth. These results qualify mannosylation as an efficient strategy to target immune cells in cancer vaccination and emphasize the potential of these glycopolycations as effective delivery vehicles for nucleic acids.

Characterization of a Nanovaccine Platform Based on an α1,2-Mannobiose Derivative Shows Species-non-specific Targeting to Human, Bovine, Mouse, and Teleost Fish Dendritic Cells.

Dendritic cells serve as the main immune cells that trigger the immune response. We developed a simple and cost-effective nanovaccine platform based on the α1',2-mannobiose derivative for dendritic cell targeting. In previous work, we have formulated the α1,2-mannobiose-based nanovaccine platform with plasmid DNA and tested it in cattle against BoHV-1 infection. There, we have shown that the dendritic cell targeting using this nanovaccine platform in vivo can boost the immunogenicity, resulting in a long-lasting immunity. In this work, we aim to characterize the α1',2-mannobiose derivative, which is key in the nanovaccine platform. This DC-targeting strategy takes advantage of the specific receptor known as DC-SIGN and exploits its capacity to bind α1,2-mannobiose that is present at terminal ends of oligosaccharides in certain viruses, bacteria, and other pathogens. The oxidative conjugation of α1',2-mannobiose to NH2-PEG2kDa-DSPE allowed us to preserve the chemical structure of the non-reducing mannose of the disaccharide and the OH groups and the stereochemistry of all carbons of the reducing mannose involved in the binding to DC-SIGN. Here, we show specific targeting to DC-SIGN of decorated micelles incubated with the Raji/DC-SIGN cell line and uptake of targeted liposomes that took place in human, bovine, mouse, and teleost fish DCs in vitro, by flow cytometry. Specific targeting was found in all cultures, demonstrating a species-non-specific avidity for this ligand, which opens up the possibility of using this nanoplatform to develop new vaccines for various species, including humans.

Chronic Systemic Curcumin Administration Antagonizes Murine Sarcopenia and Presarcopenia.

Curcumin administration attenuates muscle disuse atrophy, but its effectiveness against aging-induced, selective loss of mass or force (presarcopenia or asthenia/dynopenia), or combined loss (sarcopenia), remains controversial. A new systemic curcumin treatment was developed and tested in 18-month-old C57BL6J and C57BL10ScSn male mice. The effects on survival, liver toxicity, loss of muscle mass and force, and satellite cell responsivity and commitment were evaluated after 6-month treatment. Although only 24-month-old C57BL10ScSn mice displayed age-related muscle impairment, curcumin significantly increased survival of both strains (+20-35%), without signs of liver toxicity. Treatment prevented sarcopenia in soleus and presarcopenia in EDL of C57BL10ScSn mice, whereas it did not affect healthy-aged muscles of C57BL6J. Curcumin-treated old C57BL10ScSn soleus preserved type-1 myofiber size and increased type-2A one, whereas EDL maintained adult values of total myofiber number and fiber-type composition. Mechanistically, curcumin only partially prevented the age-related changes in protein level and subcellular distribution of major costamere components and regulators. Conversely, it affected satellite cells, by maintaining adult levels of myofiber maturation in old regenerating soleus and increasing percentage of isolated, MyoD-positive satellite cells from old hindlimb muscles. Therefore, curcumin treatment successfully prevents presarcopenia and sarcopenia development by improving satellite cell commitment and recruitment.

In Vitro and in Vivo Behavior of Liposomes Decorated with PEGs with Different Chemical Features.

The colloidal stability, in vitro toxicity, cell association, and in vivo pharmacokinetic behavior of liposomes decorated with monomethoxy-poly(ethylene glycol)-lipids (mPEG-lipids) with different chemical features were comparatively investigated. Structural differences of the mPEG-lipids used in the study included: (a) surface-anchoring moiety [1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE), cholesterol (Chol), and cholane (Chln)]; (b) mPEG molecular weight (2 kDa mPEG45 and 5 kDa mPEG114); and (c) mPEG shape (linear and branched PEG). In vitro results demonstrated that branched (mPEG114)2-DSPE confers the highest stealth properties to liposomes (∼31-fold lower cell association than naked liposomes) with respect to all PEGylating agents tested. However, the pharmacokinetic studies showed that the use of cholesterol as anchoring group yields PEGylated liposomes with longer permeance in the circulation and higher systemic bioavailability among the tested formulations. Liposomes decorated with mPEG114-Chol had 3.2- and ∼2.1-fold higher area under curve (AUC) than naked liposomes and branched (mPEG114)2-DSPE-coated liposomes, respectively, which reflects the high stability of this coating agent. By comparing the PEGylating agents with same size, namely, linear 5 kDa PEG derivatives, linear mPEG114-DSPE yielded coated liposomes with the best in vitro stealth performance. Nevertheless, the in vivo AUC of liposomes decorated with linear mPEG114-DSPE was lower than that obtained with liposomes decorated with linear mPEG114-Chol. Computational molecular dynamics modeling provided additional insights that complement the experimental results.

Dexamethasone Loaded Liposomes by Thin-Film Hydration and Microfluidic Procedures: Formulation Challenges.

Liposomes have been one of the most exploited drug delivery systems in recent decades. However, their large-scale production with low batch-to-batch differences is a challenge for industry, which ultimately delays the clinical translation of new products. We have investigated the effects of formulation parameters on the colloidal and biopharmaceutical properties of liposomes generated with a thin-film hydration approach and microfluidic procedure. Dexamethasone hemisuccinate was remotely loaded into liposomes using a calcium acetate gradient. The liposomes produced by microfluidic techniques showed a unilamellar structure, while the liposomes produced by thin-film hydration were multilamellar. Under the same remote loading conditions, a higher loading capacity and efficiency were observed for the liposomes obtained by microfluidics, with low batch-to-batch differences. Both formulations released the drug for almost one month with the liposomes prepared by microfluidics showing a slightly higher drug release in the first two days. This behavior was ascribed to the different structure of the two liposome formulations. In vitro studies showed that both formulations are non-toxic, associate to human Adult Retinal Pigment Epithelial cell line-19 (ARPE-19) cells, and efficiently reduce inflammation, with the liposomes obtained by the microfluidic technique slightly outperforming. The results demonstrated that the microfluidic technique offers advantages to generate liposomal formulations for drug-controlled release with an enhanced biopharmaceutical profile and with scalability.

1H-NMR metabolomics reveals the Glabrescione B exacerbation of glycolytic metabolism beside the cell growth inhibitory effect in glioma.

BACKGROUND: Glioma is the most common and primary brain tumors in adults. Despite the available multimodal therapies, glioma patients appear to have a poor prognosis. The Hedgehog (Hh) signaling is involved in tumorigenesis and emerged as a promising target for brain tumors. Glabrescione B (GlaB) has been recently identified as the first direct inhibitor of Gli1, the downstream effector of the pathway. METHODS: We established the overexpression of Gli1 in murine glioma cells (GL261) and GlaB effect on cell viability. We used 1H-nuclear magnetic resonance (NMR) metabolomic approach to obtain informative metabolic snapshots of GL261 cells acquired at different time points during GlaB treatment. The activation of AMP activated protein Kinase (AMPK) induced by GlaB was established by western blot. After the orthotopic GL261 cells injection in the right striatum of C57BL6 mice and the intranasal (IN) GlaB/mPEG5kDa-Cholane treatment, the tumor growth was evaluated. The High Performance Liquid Chromatography (HPLC) combined with Mass Spectrometry (MS) was used to quantify GlaB in brain extracts of treated mice. RESULTS: We found that GlaB affected the growth of murine glioma cells both in vitro and in vivo animal model. Using an untargeted 1H-NMR metabolomic approach, we found that GlaB stimulated the glycolytic metabolism in glioma, increasing lactate production. The high glycolytic rate could in part support the cytotoxic effects of GlaB, since the simultaneous blockade of lactate efflux with α-cyano-4-hydroxycinnamic acid (ACCA) affected glioma cell growth. According to the metabolomic data, we found that GlaB increased the phosphorylation of AMPK, a cellular energy sensor involved in the anabolic-to-catabolic transition. CONCLUSIONS: Our results indicate that GlaB inhibits glioma cell growth and exacerbates Warburg effect, increasing lactate production. In addition, the simultaneous blockade of Gli1 and lactate efflux amplifies the anti-tumor effect in vivo, providing new potential therapeutic strategy for this brain tumor.

Novel Oligo-Guanidyl-PEG Carrier Forming Rod-Shaped Polyplexes.

A novel unconventional supramolecular oligo-cationic structure (Agm6-M-PEG-OCH3) has been synthesized to yield high efficiency therapeutic oligonucleotide (ON) delivery. Agm6-M-PEG-OCH3 was obtained by a multistep protocol that included the conjugation of agmatine (Agm) moieties to maltotriose (M), which was further derivatized with one poly(ethylene glycol) (PEG) chain. Gel electrophoresis analysis showed that the 19 base pairs dsDNA model ON completely associates with Agm6-M-PEG-OCH3 at 3 N/P molar ratio, which is in agreement with the in silico molecular predictions. Isothermal titration calorimetry (ITC) analyses showed that the Agm6-M-PEG-OCH3/ON association occurs through a combination of mechanisms depending on the N/P ratios resulting in different nanostructures. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed that the Agm6-M-PEG-OCH3/ON polyplexes have rod-shape structure with a mean diameter of 50-75 nm and aspect ratio depending on the N/P ratio. The polyplexes were stable over time in buffer, while a slight size increase was observed in the presence of serum proteins. Cell culture studies showed that neither Agm6-M-PEG-OCH3 nor polyplexes displayed cytotoxic effects. Cellular uptake depended on the cell line and polyplex composition: cellular internalization was higher in the case of MCF-7 and KB cells compared to MC3T3-E1 cells and polyplexes with smaller aspect ratio were taken-up by cells more efficiently than polyplexes with higher aspect ratio. Finally, preliminary studies showed that our novel carrier efficiently delivered ONs into cells providing gene silencing.

Switching of Macromolecular Ligand Display by Thermoresponsive Polymers Mediates Endocytosis of Multiconjugate Nanoparticles.

Ligand-mediated targeting and internalization of plasma membrane receptors is central to cellular function. These types of receptors have accordingly been investigated as targets to facilitate entry of diagnostic and therapeutic constructs into cells. However, there remains a need to characterize how receptor targeting agents on nanoparticles interact at surface receptors and whether it is possible to control these interactions via exogenous stimuli. Here, we describe the switchable display of the iron-transporting protein, transferrin (Tf), at the surface of thermoresponsive polymer-coated gold nanoparticles and show that internalization of the coated nanoparticles into target cells changes across temperature ranges over which transferrin is expected to be sterically "hidden" by an extended polymer chain and then "revealed" by polymer chain collapse. The switching process is dependent on the numbers of transferrin molecules and thermoresponsive polymer chains attached and whether the assay temperature is above or below the transition temperatures of the responsive polymers at the nanoparticle surfaces. Significantly, however, the control of internalization is critically reliant on overall nanoparticle colloidal stability while the thermoresponsive component of the surface undergoes conformational change. The data show that the cell entry function of complex and large biomolecule ligands can be modulated by polymer-induced accessibility change but that a simple "hide and reveal" mechanism for ligand display following polymer chain collapse is insufficient to account for nanoparticle uptake and subsequent intracellular trafficking.

Control of Peptide Aggregation and Fibrillation by Physical PEGylation.

Peptide therapeutics have the potential to self-associate, leading to aggregation and fibrillation. Noncovalent PEGylation offers a strategy to improve their physical stability; an understanding of the behavior of the resulting polymer/peptide complexes is, however, required. In this study, we have performed a set of experiments with additional mechanistic insight provided by in silico simulations to characterize the molecular organization of these complexes. We used palmitoylated vasoactive intestinal peptide (VIP-palm) stabilized by methoxy-poly(ethylene glycol)5kDa-cholane (PEG-cholane) as our model system. Homogeneous supramolecular assemblies were found only when complexes of PEG-cholane/VIP-palm exceeded a molar ratio of 2:1; at and above this ratio, the simulations showed minimal exposure of VIP-palm to the solvent. Supramolecular assemblies formed, composed of, on average, 9-11 PEG-cholane/VIP-palm complexes with 2:1 stoichiometry. Our in silico results showed the structural content of the helical conformation in VIP-palm increases when it is complexed with the PEG-cholane molecule; this behavior becomes yet more pronounced when these complexes assemble into larger supramolecular assemblies. Our experimental results support this: the extent to which VIP-palm loses helical structure as a result of thermal denaturation was inversely related to the PEG-cholane:VIP-palm molar ratio. The addition of divalent buffer species and increasing the ionic strength of the solution both accelerate the formation of VIP-palm fibrils, which was partially and fully suppressed by 2 and >4 mol equivalents of PEG-cholane, respectively. We conclude that the relative freedom of the VIP-palm backbone to adopt nonhelical conformations is a key step in the aggregation pathway.

CNA-loaded PLGA nanoparticles improve humoral response againstS. aureus-mediated infections in a mouse model: subcutaneous vs. nasal administration strategy.

The aim of this work was the assessment of the "in vivo" immune response of a poly(lactide-co-glycolide)-based nanoparticulate adjuvant for a sub-unit vaccine, namely, a purified recombinant collagen-binding bacterial adhesion fragment (CNA19), against Staphylococcus aureus-mediated infections. "In vivo" immunogenicity studies were performed on mice: immunisation protocols encompassed subcutaneous and intranasal administration of CNA19 formulated as nanoparticles (NPs) and furthermore, CNA19-loaded NPs formulated in a set-up thermosetting chitosan-ß-glycerolphosphate (chitosan-ß-GP) solution for intranasal route in order to extend antigen exposure to nasal mucosa. CNA19 loaded NPs (mean size of about 195 nm, 9.04 ± 0.37µg/mg as CNA19 loading capacity) confirmed as suitable vaccine for subcutaneous administration with a more pronounced adjuvant effect (about 3-fold higher) with respect to aluminium, recognised as "reference" adjuvant. CNA19 loaded NPs formulated in an optimised thermogelling chitosan-ß-GP solution showed promising results for eliciting an effective humoral response and a good chance as intranasal boosting dose.

Novel pullulan bioconjugate for selective breast cancer bone metastases treatment.

A novel polysaccharide bioconjugate was designed to selectively target breast cancer bone metastases using a bisphosphonate moiety (alendronate, ALN). Paclitaxel (PTX) was first covalently conjugated to pullulan (Pull) through a Cathepsin K-sensitive tetrapeptide spacer followed by a self-immolative aminobenzyl alcohol spacer to obtain Pull-(GGPNle-φ-PTX). ALN was then conjugated to the polymeric backbone of Pull-(GGPNle-φ-PTX) via a PEG spacer. The final bioconjugate Pull-(GGPNle-φ-PTX)-(PEG-ALN) was found to assemble into colloidal spherical structures, which were physically and chemically stable under physiological conditions. In vitro studies showed that Pull-(GGPNle-φ-PTX)-(PEG-ALN) had strong affinity for hydroxyapatite, which simulates the bone tissue. Paclitaxel was rapidly released from the bioconjugate by Cathepsin K cleavage under pathological conditions. All studies performed using human MDA-MB-231-BM (bone metastases-originated clone), murine 4T1 breast cancer cells, murine K7M2, and human SAOS-2 osteosarcoma cells showed that the bioconjugate exerted an enhanced antiproliferative activity compared to the conjugate without the ALN. Furthermore, the nanoconjugate inhibited the migration of cancer cells and further displayed potent anti-angiogenic activity. In conclusion, the results showed that this conjugate has an excellent potential for selective treatment of bone neoplasms such as breast cancer bone metastases and osteosarcoma.

Triblock Copolymer Nanovesicles for pH-Responsive Targeted Delivery and Controlled Release of siRNA to Cancer Cells.

New pH-responsive polymersomes for active anticancer oligonucleotide delivery were prepared from triblock copolymers. The delivery systems were formed by two terminal hydrophilic blocks, PEG and polyglycerolmethacrylate (poly-GMA), and a central weakly basic block, polyimidazole-hexyl methacrylate (poly-ImHeMA), which can complex with oligonucleotides and control vesicle formation/disassembly via pH variations. Targeted polymersomes were prepared by mixing folate-derivatized and underivatized copolymers. At pH 5, ds-DNA was found to complex with the pH-responsive copolymers at a N/P molar ratio above ∼2:1, which assisted the encapsulation of ds-DNA in the polymersomes, while low association was observed at pH 7.4. Cytotoxicity studies performed on folate receptor overexpressing KB and B16-F10 cells and low folate receptor expressing MCF-7 cells showed high tolerance of the polymersomes at up to 3 mg/mL concentration. Studies performed with red blood cells showed that at pH 5.0 the polymersomes have endosomolytic properties. Cytofluorimetric studies showed a 5.5-fold higher uptake of ds-DNA loaded folate-functional polymersomes in KB cells compared to nontargeted polymersomes. In addition, ds-DNA was found to be localized both in the nucleus and in the cytosol. The incubation of luciferase transfected B16-F10 cells with targeted polymersomes loaded with luciferase and Hsp90 expression silencing siRNAs yielded 31 and 23% knockdown in target protein expression, respectively.

Priming with oncolytic adenovirus followed by anti-PD-1 and paclitaxel treatment leads to improved anti-cancer efficacy in the 3D TNBC model.

Triple-negative breast cancer (TNBC) is considered one of the most incurable malignancies due to its clinical characteristics, including high invasiveness, high metastatic potential, proneness to relapse, and poor prognosis. Therefore, it remains a critical unmet medical need. On the other hand, poor delivery efficiency continues to reduce the efficacy of anti-cancer therapeutics developed against solid tumours using various strategies, such as genetically engineered oncolytic vectors used as nanocarriers. The study was designed to evaluate the anti-tumour efficacy of a novel combinatorial therapy based on oncolytic adenovirus AdV5/3-D24-ICOSL-CD40L with an anti-PD-1 (pembrolizumab) and paclitaxel (PTX). Here, we first tested the antineoplastic effect in two-dimensional (2D) and three-dimensional (3D) breast cancer models in MDA-MB-231, MDA-MB-468 and MCF-7 cells. Then, to further evaluate the efficacy of combinatorial therapy, including immunological aspects, we established a three-dimensional (3D) co-culture model based on MDA-MB-231 cells with peripheral blood mononuclear cells (PBMCs) to create an integrated system that more closely mimics the complexity of the tumour microenvironment and interacts with the immune system. Treatment with OV as a priming agent, followed by pembrolizumab and then paclitaxel, was the most effective in reducing the tumour volume in TNBC co-cultured spheroids. Further, T-cell phenotyping analyses revealed significantly increased infiltration of CD8+, CD4+ T and Tregs cells. Moreover, the observed anti-tumour effects positively correlated with the level of CD4+ T cell infiltrates, suggesting the development of anti-cancer immunity. Our study demonstrated that combining different immunotherapeutic agents (virus, pembrolizumab) with PTX reduced the tumour volume of the TNBC co-cultured spheroids compared to relevant controls. Importantly, sequential administration of the investigational agents (priming with the vector) further enhanced the anti-cancer efficacy in 3D culture over other groups tested. Taken together, these results support further evaluation of the virus in combination with anti-PD-1 and PTX for the treatment of triple-negative breast cancer patients. Importantly, further studies with in vivo models should be conducted to better understand the translational aspects of tested therapy.

Influence of Folate-Targeted Gold Nanoparticles on Subcellular Localization and Distribution into Lysosomes.

The cell interaction, mechanism of cell entry and intracellular fate of surface decorated nanoparticles are known to be affected by the surface density of targeting agents. However, the correlation between nanoparticles multivalency and kinetics of the cell uptake process and disposition of intracellular compartments is complicated and dependent on a number of physicochemical and biological parameters, including the ligand, nanoparticle composition and colloidal properties, features of targeted cells, etc. Here, we have carried out an in-depth investigation on the impact of increasing folic acid density on the kinetic uptake process and endocytic route of folate (FA)-targeted fluorescently labelled gold nanoparticles (AuNPs). A set of AuNPs (15 nm mean size) produced by the Turkevich method was decorated with 0-100 FA-PEG3.5kDa-SH molecules/particle, and the surface was saturated with about 500 rhodamine-PEG2kDa-SH fluorescent probes. In vitro studies carried out using folate receptor overexpressing KB cells (KBFR-high) showed that the cell internalization progressively increased with the ligand surface density, reaching a plateau at 50:1 FA-PEG3.5kDa-SH/particle ratio. Pulse-chase experiments showed that higher FA density (50 FA-PEG3.5kDa-SH molecules/particle) induces more efficient particle internalization and trafficking to lysosomes, reaching the maximum concentration in lysosomes at 2 h, than the lower FA density of 10 FA-PEG3.5kDa-SH molecules/particle. Pharmacological inhibition of endocytic pathways and TEM analysis showed that particles with high folate density are internalized predominantly by a clathrin-independent process.

Control of cell penetration enhancer shielding and endosomal escape-kinetics crucial for efficient and biocompatible siRNA delivery.

Although cationic liposomes are efficient carriers for nucleic acid delivery, their toxicity often hampers the clinical translation. Polyethylene glycol (PEG) coating has been largely used to improve their stability and reduce toxicity. Nevertheless, it has been found to decrease the transfection process. In order to exploit the advantages of cationic liposomes and PEG decoration for nucleic acid delivery, liposomes decorated with tetraArg-[G-1]-distearoyl glycerol (Arg4-DAG) dendronic oligo-cationic lipid enhancer (OCE) and PEG-lipid have been investigated. Non decorated or OCE-decorated lipoplexes (OCEfree-LPX and OCE-LPX, respectively) were obtained by lipid film hydration using oligonucleotide (ON) solutions. PEG and OCE/PEG decorated lipoplexes (PEG-OCEfree-LPX and PEG-OCE-LPX, respectively) were obtained by post-insertion of 2 or 5 kDa PEG-DSPE on preformed lipoplexes. The OCE decoration yielded lipoplexes with size of about 240 nm, 84% loading efficiency at 10 N/P ratio, ten times higher than OCEfree-LPX, and prevented the ON release when incubated with physiological heparin concentration or with plasma. The PEG decoration reduced the zeta potential, enhanced the lipoplex stability in serum and decreased both hemolysis and cytotoxicity, while it did not affect the lipoplex size and ON loading. With respect to OCEfree-LPX, the OCE-LPX remarkably associated with cells and were taken up by different cancer cell lines (HeLa and MDA-MB-231). Interestingly, 2 or 5 kDa PEG decoration did not reduce either the cell interaction or the cell up-take of the cationic lipoplexes. With siRNA as a payload, OCE enabled efficient internalization, but endosomal release was hampered. Post-transfection treatment with the lysosomotropic drug chloroquine allowed to identify the optimal time point for endosomal escape. Chloroquine treatment after 12 to 20 h of LPX pre-incubation enabled siRNA mediated target knockdown indicating that this is the time window of endo-lysosomal processing. This indicates that OCE can protect siRNA from lysosomal degradation for up to 20 h, as shown by these rescue experiments.

Tailoring surface properties of liposomes for dexamethasone intraocular administration.

Diseases of the posterior eye segment are often characterized by intraocular inflammation, which causes, in the long term, severe impairment of eye functions and, ultimately, vision loss. Aimed at enhancing the delivery of anti-inflammatory drugs to the posterior eye segment upon intravitreal administration, we developed liposomes with an engineered surface to control their diffusivity in the vitreous and retina association. Hydrogenated soybean phosphatidylcholine (HSPC)/cholesterol liposomes were coated with (agmatinyl)6-maltotriosyl-acetamido-N-(octadec-9-en-1-yl)hexanamide (Agm6-M-Oleate), a synthetic non-peptidic cell penetration enhancer (CPE), and/or 5% of mPEG2kDa-DSPE. The zeta potential of liposomes increased, and the mobility in bovine vitreous and colloidal stability decreased with the Agm6-M-Oleate coating concentration. Oppositely, mPEG2kDa-DSPE decreased the zeta potential of liposomes and restored both the diffusivity and the stability in vitreous. Liposomes with 5 mol% Agm6-M-Oleate coating were well tolerated by ARPE-19 retina cells either with or without mPEG2kDa-DSPE, while 10 mol% Agm6-M-Oleate showed cytotoxicity. Agm6-M-Oleate promoted the association of liposomes to ARPE-19 cells with respect to plain liposomes, while mPEG2kDa-DSPE slightly reduced the cell interaction. Dexamethasone hemisuccinate (DH) was remotely loaded into liposomes with a loading capacity of ∼10 wt/wt%. Interestingly, mPEG2kDa-DSPE coating reduced the rate of DH release and enhanced the disposition of Agm6-M-Oleate coated liposomes in the ARPE-19 cell cytosol resulting in a more efficient anti-inflammatory effect. Finally, mPEG2kDa-DSPE enhanced the association of DH-loaded Agm6-M-Oleate coated liposomes to explanted rat retina, which reflected in higher viability of inner and outer nuclear layer cells.

Novel combinatorial therapy of oncolytic adenovirus AdV5/3-D24-ICOSL-CD40L with anti PD-1 exhibits enhanced anti-cancer efficacy through promotion of intratumoral T-cell infiltration and modulation of tumour microenvironment in mesothelioma mouse model.

Introduction: Malignant mesothelioma is a rare and aggressive form of cancer. Despite improvements in cancer treatment, there are still no curative treatment modalities for advanced stage of the malignancy. The aim of this study was to evaluate the anti-tumor efficacy of a novel combinatorial therapy combining AdV5/3-D24-ICOSL-CD40L, an oncolytic vector, with an anti-PD-1 monoclonal antibody. Methods: The efficacy of the vector was confirmed in vitro in three mesothelioma cell lines - H226, Mero-82, and MSTO-211H, and subsequently the antineoplastic properties in combination with anti-PD-1 was evaluated in xenograft H226 mesothelioma BALB/c and humanized NSG mouse models. Results and discussion: Anticancer efficacy was attributed to reduced tumour volume and increased infiltration of tumour infiltrating lymphocytes, including activated cytotoxic T-cells (GrB+CD8+). Additionally, a correlation between tumour volume and activated CD8+ tumour infiltrating lymphocytes was observed. These findings were confirmed by transcriptomic analysis carried out on resected human tumour tissue, which also revealed upregulation of CD83 and CRTAM, as well as several chemokines (CXCL3, CXCL9, CXCL11) in the tumour microenvironment. Furthermore, according to observations, the combinatorial therapy had the strongest effect on reducing mesothelin and MUC16 levels. Gene set enrichment analysis suggested that the combinatorial therapy induced changes to the expression of genes belonging to the "adaptive immune response" gene ontology category. Combinatorial therapy with oncolytic adenovirus with checkpoint inhibitors may improve anticancer efficacy and survival by targeted cancer cell destruction and triggering of immunogenic cell death. Obtained results support further assessment of the AdV5/3-D24-ICOSL-CD40L in combination with checkpoint inhibitors as a novel therapeutic perspective for mesothelioma treatment.

Star-like oligo-arginyl-maltotriosyl derivatives as novel cell-penetrating enhancers for the intracellular delivery of colloidal therapeutic systems.

A novel nonpeptide, multiarmed oligo-arginyl derivative was engineered as a cell-penetration enhancer for the delivery of bioactive macromolecules and colloidal drug systems. Hepta-arginyl-maltotriosylamido-N-acetyl-dodecanoyl acid (Arg(7)-Malt-NAcC(12) acid) was synthesized through a carefully designed multistep chemical protocol, as follows: (1) maltotriose derivatization with 12-amino-dodecanoic acid and acetylation of the free amino group; (2) esterification of the maltotriosyl hydroxyl groups with 2-bromo-isobutyryl bromide; and (3) synthesis of star-like oligomer bearing multiple copies of arginine moieties under atom transfer radical polymerization (ATRP) conditions. The intermediates and final product were characterized by (1)H NMR, IR, mass spectrometry, colorimetric assays, and elemental analysis. Cytotoxicity studies on the final polymeric material showed that this novel cell-penetrating enhancer does not have significant toxic effects on MCF-7 and MC3T3-E1 cell lines. The IC(50) was greater than 100 µM with both cell lines, while the polyethylenimine with similar average molecular mass (M(n)) that was used as a reference showed an IC(50) of 30 and 40 µM, for MCF-7 and MC3T3-E1, respectively. The biological properties of the novel bioconjugate were investigated using a fluorescein-labeled bovine serum albumin (FITC-BSA) as a hydrophilic cargo model. MCF-7 and MC3T3-E1 cells were incubated for 60 min with the Arg(7)-Malt-NAcC(12)-conjugated FITC-BSA [(Arg(7)-Malt-NAcC(12))(2)-FITC-BSA] or FITC-BSA, and the intracellular fluorescence level was analyzed by spectrofluorimetric analysis of cell lysate, cytofluorimetry, and confocal microscopy. The fluorescence of the lysate of MCF-7 and MC3T3-E1 cells that were incubated with (Arg(7)-Malt-NAcC(12))(2)-FITC-BSA at 37 °C was approximately 4.5 times higher than the fluorescence obtained with cells incubated with FITC-BSA. At 4 °C, the cell uptake of (Arg(7)-Malt-NAcC(12))(2)-FITC-BSA was only 2 times higher than that of FITC-BSA. Cytofluorimetric studies showed that, after (Arg(7)-Malt-NAcC(12))(2)-FITC-BSA treatment, over 80% of MCF-7 cells and over 95% of MC3T3-E1 cells displayed enhanced fluorescence. Confocal investigations showed punctuated fluorescence within the cytosol in both cell lines, indicating that (Arg(7)-Malt-NAcC(12))(2)-FITC-BSA was confined to endosomes, with no fluorescence observed in the nucleus.

From Immunosuppression to Immunomodulation - Turning Cold Tumours into Hot.

Cancer cells employ various mechanisms to evade and suppress anti-cancer immune responses generating a "cold" immunosuppressive tumour microenvironment. Oncolytic viruses are a promising tool to convert tumour immunosuppression to immunomodulation and improve the efficacy of cancer treatment. Emerging preclinical and clinical findings confirm that oncolytic viruses act in a multimodal scheme, triggering lyses, immunogenic cell death and finally inducing anti-cancer immune responses. In this paper, we tested the local administration of a novel oncolytic adenovirus AdV-D24-ICOSL-CD40L expressing co-stimulatory molecules ICOSL and CD40L to induce the production of tumour infiltrating lymphocytes to the site of injection. Subsequently, in immunocompetent mouse models, we studied possible correlation between tumour infiltrates and anti-cancer efficacy. Described results showed that the delivery of oncolytic viruses encoding immunomodulatory transgenes in combination with anti-PD1 resulted in synergistic inhibition of both melanoma and mesothelioma tumours. Importantly anti-cancer effect positively correlated with cytotoxic CD8+ tumour-infiltrating lymphocytes exerting a central role in the tumour volume control thus generating beneficial outcomes that will undoubtedly provide new insights into possible future treatment strategies to combat cancer. Altogether our findings highlight the importance of oncolytic vectors able to modulate anti-cancer immune responses that can correlate with efficacy in solid malignancies.