Influence of Endosomal Escape and Degradation of α-Galactosylceramide Loaded Liposomes on CD1d Antigen Presentation

One-pot, degradable, silica nanocarriers with encapsulated oligonucleotides for mitochondrial specific targeting

Mutations in nuclear and mitochondrial genes are responsible for severe chronic disorders such as mitochondrial myopathies. Gene therapy using antisense oligonucleotides is a promising strategy to treat mitochondrial DNA (mtDNA) diseases by blocking the replication of the mutated mtDNA. However, transport vehicles are needed for intracellular, mitochondria-specific transport of oligonucleotides. Nanoparticle (NP) based vectors such as large pore mesoporous silica nanoparticles (LP) often rely on surface complexation of oligonucleotides exposing them to nucleases and limiting mitochondria targeting and controlled release ability. In this work, stable, fluorescent, hollow silica nanoparticles (HSN) that encapsulate and protect oligonucleotides in the hollow core were synthesized by a facile one-pot procedure. Both rhodamine B isothiocyanate and bis[3-(triethoxysilyl)propyl]tetrasulfide were incorporated in the HSN matrix by co-condensation to enable cell tracing, intracellular-specific degradation and controlled oligonucleotide release. We also synthesized LP as a benchmark to compare the oligonucleotide loading and release efficacy of our HSN. Mitochondria targeting was enabled by NP functionalization with cationic, lipophilic Triphenylphosphine (TPP) and, for the first time a fusogenic liposome based carrier, previously reported under the name MITO-Porter. HSN exhibited high oligonucleotide incorporation ratios and release dependent on intracellular degradation. Further, MITO-Porter capping of our NP enabled delayed, glutathione (GSH) responsive oligonucleotide release and mitochondria targeting at the same efficiency as TPP functionalized NP. Overall, our NP are promising vectors for anti-gene therapy of mtDNA disease as well as many other monogenic disorders worldwide.

Thermotropic Behavior and Structural Organization of C24:1 Sulfatide Dispersions and Its Mixtures with Cationic Bilayers

C24:1 sulfatide (SF) is an endogenous activator of type II NKT cells. The thermotropic behavior and structure of SF dispersions and its mixtures (4.8-16.6 mol %) with cationic dioctadecyldimethylammonium bromide (DODAB) bilayers were investigated by differential scanning calorimetry and electron paramagnetic resonance spectroscopy. The non-interdigitated lamellar structures formed by pure SF display broad thermal events around 27.5 °C when heated and cooled. These events disappear upon mixing with DODAB, showing complete lipid miscibility. SF decreases the DODAB gel-phase packing, with a consequent decrease in phase-transition temperatures and cooperativity upon heating. In contrast, SF increases the rigidity of the DODAB fluid phase, resulting in a smaller decrease in transition temperatures upon cooling. The hysteresis between heating and cooling decreased as the SF molar fraction increased. These effects on DODAB are similar to the ones described for other glycolipids, such as αGalCer and βGlcCer. This might be due to the orientation of the rigid and planar amide bond that connects their sphingoid bases and acyl chains, which result in a V-shaped conformation of the glycolipid molecules. The current results may be important to plan and develop new immunotherapeutic tools based on SF.

Retrograde Axonal Transport of Liposomes from Peripheral Tissue to Spinal Cord and DRGs by Optimized Phospholipid and CTB Modification

Despite recent advancements in therapeutic options for disorders of the central nervous system (CNS), the lack of an efficient drug-delivery system (DDS) hampers their clinical application. We hypothesized that liposomes could be optimized for retrograde transport in axons as a DDS from peripheral tissues to the spinal cord and dorsal root ganglia (DRGs). Three types of liposomes consisting of DSPC, DSPC/POPC, or POPC in combination with cholesterol (Chol) and polyethylene glycol (PEG) lipid were administered to sciatic nerves or the tibialis anterior muscle of mature rats. Liposomes in cell bodies were detected with infrared fluorescence of DiD conjugated to liposomes. Three days later, all nerve-administered liposomes were retrogradely transported to the spinal cord and DRGs, whereas only muscle-administered liposomes consisting of DSPC reached the spinal cord and DRGs. Modification with Cholera toxin B subunit improved the transport efficiency of liposomes to the spinal cord and DRGs from 4.5% to 17.3% and from 3.9% to 14.3% via nerve administration, and from 2.6% to 4.8% and from 2.3% to 4.1% via muscle administration, respectively. Modification with octa-arginine (R8) improved the transport efficiency via nerve administration but abolished the transport capability via muscle administration. These findings provide the initial data for the development of a novel DDS targeting the spinal cord and DRGs via peripheral administration.

Innovative cancer nanomedicine based on immunology, gene editing, intracellular trafficking control

The recent rapid progress in the area of drug delivery systems (DDS) has opened a new era in medicine with a strong linkage to understanding the molecular mechanisms associated with cancer survival. In this review, we summarize new cancer strategies that have recently been developed based on our DDS technology. Cancer immunotherapy will be improved based on the concept of the cancer immunity cycle, which focuses on dynamic interactions between various types of cancer and immune cells in our body. The new technology of genome editing will also be discussed with reference to how these new DDS technologies can be used to introduce therapeutic cargoes into our body. Lastly, a new organelle, mitochondria will be the focus of creating a new cancer treatment strategy by a MITO-Porter which can deliver macromolecules directly to mitochondria of cancer cells via a membrane fusion approach and the impact of controlled intracellular trafficking will be discussed.

Glucosylceramide in T cells regulates the pathology of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease in the colon characterized by excessive activation of T cells. Glycosphingolipids (GSLs) are composed of lipid rafts in cellular membranes, and their content is linked to immune cell function. In the present study, we investigated the involvement of GSLs in IBD. Microarray data showed that in IBD patients, the expression of only UDP-glucose ceramide glucosyltransferase (UGCG) decreased among the GSLs synthases. Ad libitum access to dextran sulfate sodium (DSS) resulted in decreased UGCG and glucosylceramide (GlcCer) content in mesenteric lymph nodes and T cells from the spleen. Furthermore, the knockdown of Ugcg in T cells exacerbated the pathogenesis of colitis, which was accompanied by a decrease in Treg levels. Treatment with GlcCer nanoparticles prevented DSS-induced colitis. These results suggested that GlcCer in T cells is involved in the pathogenesis of IBD. Furthermore, GlcCer nanoparticles are a potential efficacious therapeutic target for IBD patients.

MUC1 Specific Immune Responses Enhanced by Coadministration of Liposomal DDA/MPLA and Lipoglycopeptide

Mucin 1 (MUC1), a well-known tumor-associated antigen and attractive target for tumor immunotherapy, is overexpressed in most human epithelial adenomas with aberrant glycosylation. However, its low immunogenicity impedes the development of MUC1-targeted antitumor vaccines. In this study, we investigated three liposomal adjuvant systems containing toll-like receptor 4 (TLR4) agonist monophosphoryl lipid A (MPLA) and auxiliary lipids of different charges: cationic lipid dimethyldioctadecylammonium (DDA), neutral lipid distearoylglycerophosphocholine (DSPC) or anionic lipid dioleoylphosphatidylglycerol (DOPG), respectively. ELISA assay evidenced that the positively charged DDA/MPLA liposomes are potent immune activators, which induced remarkable levels of anti-MUC1 antibodies and exhibited robust Th1-biased immune responses. Importantly, the antibodies induced by DDA/MPLA liposomes efficiently recognized and killed MUC1-positive tumor cells through complement-mediated cytotoxicity. In addition, antibody titers in mice immunized with P2-MUC1 vaccine were significantly higher than those from mice immunized with P1-MUC1 or MUC1 vaccine, which indicated that the lipid conjugated on MUC1 antigen also played important role for immunomodulation. This study suggested that the liposomal DDA/MPLA with lipid-MUC1 is a promising antitumor vaccine, which can be used for the immunotherapy of various epithelial carcinomas represented by breast cancer.

Recent Advancements in Liposome-Targeting Strategies for the Treatment of Gliomas: A Systematic Review

Malignant tumors represent some of the most intractable diseases that endanger human health. A glioma is a tumor of the central nervous system that is characterized by severe invasiveness, blurred boundaries between the tumor and surrounding normal tissue, difficult surgical removal, and high recurrence. Moreover, the blood-brain barrier (BBB) and multidrug resistance (MDR) are important factors that contribute to the lack of efficacy of chemotherapy in treating gliomas. A liposome is a biofilm-like drug delivery system with a unique phospholipid bilayer that exhibits high affinities with human tissues/organs (e.g., BBB). After more than five decades of development, classical and engineered liposomes consist of four distinct generations, each with different characteristics: (i) traditional liposomes, (ii) stealth liposomes, (iii) targeting liposomes, and (iv) biomimetic liposomes, which offer a promising approach to promote drugs across the BBB and to reverse MDR. Here, we review the history, preparatory methods, and physicochemical properties of liposomes. Furthermore, we discuss the mechanisms by which liposomes have assisted in the diagnosis and treatment of gliomas, including drug transport across the BBB, inhibition of efflux transporters, reversal of MDR, and induction of immune responses. Finally, we highlight ongoing and future clinical trials and applications toward further developing and testing the efficacies of liposomes in treating gliomas.

Supramolecular organization of α-galactosylceramide in pure dispersions and in cationic DODAB bilayers

α-galactosylceramide (α-GalCer; KRN7000) strongly stimulates NKT cells. The structures of α-GalCer assemblies and of cationic DODAB bilayers containing α-GalCer were investigated by differential scanning calorimetry (DSC) and electron spin resonance (ESR) spectroscopy. Assemblies of α-GalCer have a very tightly packed gel phase, causing spin labels to cluster and display spin exchange interactions. An endothermic phase transition is observed by DSC, leading to a fluid phase. This phase transition peak disappears upon mixing with DODAB, showing that up to 9 mol% α-GalCer is miscible with the cationic lipid. ESR spectra show that α-GalCer decreases DODAB gel phase packing, resulting in a decrease of gel-fluid transition temperature and cooperativity in DSC thermograms of mixed bilayers. In contrast, α-GalCer increases the rigidity of the fluid phase. These effects are probably due to the conformation of the rigid amide bond that connects the phytosphingosine base of α-GalCer to its long and saturated acyl chain. Possibly, α-GalCer adopts a V-shaped conformation because of the perpendicular orientation of the amide bond towards the axes of the hydrocarbon chains. Apparently, the effect of the amide bond configuration is a key structural feature for the interaction between ceramide-based glycolipids and DODAB molecules, since we have previously reported a similar decrease of gel phase packing and increase in fluid phase rigidity for DODAB bilayers containing C24:1β-glucosylceramide. Since the structure of delivery systems is critical to the biological activity of α-GalCer, this work certainly contributes to the planning and development of novel immunotherapeutic tools.

Designing Aptamer-Gold Nanoparticle-Loaded pH-Sensitive Liposomes Encapsulate Morin for Treating Cancer

This study proposes the synthesis of a type of anticancer nanoparticle, aptamers and Au nanoparticle (Apt-Au)-modified Morin pH-sensitive liposome (MSL), which exhibits targeting properties. Tumors are difficult to cure because their microenvironment varies from that of normal tissue; its pH is lower than that of normal tissue, which generally impedes the effectiveness of drugs. Thus, pH-responsive drugs have attracted extensive attention. Gold nanoparticles (AuNPs) show potential as drug carriers because of their small size, good biocompatibility, easy surface modification, and strong cell penetration. Apt-Au@MSL exhibits excellent monodispersity and tumor-targeting properties and can be released in partly acidic environment via dialysis. We screened our model cancer cell by MTT assay and found that SGC-7901 cells can effectively suppress proliferation. In vivo results demonstrate that the administration of Apt-Au@MSL could inhibit tumor growth in xenograft mouse models. H&E staining and TUNEL assay further confirmed that Apt-Au@MSL can promote tumor apoptosis. Apt-Au@MSL may induce apoptosis by triggering overproduction of reactive oxygen species (ROS) and regulating multiple signal crosstalk. Both blood biochemistry tests and H&E staining suggested that these materials exhibit negligible acute toxicity and good biocompatibility in vivo. With its powerful function, Apt-Au@MSL can be used as a target-based anticancer material for future clinical cancer treatment.

Establishment of a hTfR mAb-functionalized HPPS theranostic nanoplatform

Rational: Many efforts have been made to develop ligand-directed nanotheranostics in cancer management which could afford both therapeutic and diagnostic functions as well as tumor-tailored targeting. Theranostic nanoplatform targeting transferrin receptor (TfR) is an effective system for favorable delivery of diagnostic and therapeutic agents to malignancy site. Methods: To enable amalgamation of therapy and diagnosis to many TfR+ tumor, hTfR (human TfR) monoclonal antibody (mAb)-functionalized HPPS nanoparticle (HPPS-mAb) was prepared with hTfR mAb on the shell and with fluorophore DiR-BOA in the core. The targeting specificity was investigated in vitro by immunostaining and in vivo using a double-tumor-engrafted mouse model. HPPS-mAb/siRNA effect on HepG2 cells was determined by RT-PCR and western blot. Results: HPPS-mAb could specifically target cancer cells through TfR and achieve tumor accumulation at an early valuable time node, thus efficiently delivering therapeutic survivin siRNA into TfR+ HepG2 cells and mediating cell apoptosis. DiR-BOA can act as an imaging tool to diagnose cancer. Conclusions: Our studies provide a promising TfR mAb-directed theranostic nanoplatform candidate in tumor molecular imaging and in TfR targeted tumor therapy.

Distribution of BCG-CWS-Loaded Nanoparticles in the Spleen After Intravenous Injection Affects Cytotoxic T Lymphocyte Activity

Interest has developed in the bacillus Calmette-Guerin (BCG) cell wall skeleton (BCG-CWS) as a noninfectious adjuvant. Although BCG-CWS readily undergoes aggregation, in a previous study, we applied it to cancer immunotherapy via intravenous administration by encapsulating the BCG-CWS into nanoparticles (CWS-NPs). The CWS-NPs were taken up by major histocompatibility complex (MHC) class II⁺ (MHC-II⁺) cells and induced antigen-specific cytotoxic T lymphocyte (CTL) activity. However, the nature of the contribution of MHC-II⁺ cells to the CTL response continues to be unclear. In this study, we investigated the relationship between the distribution of CWS-NPs in the spleen and CTL activity. The main MHC-II⁺ cells that internalized the CWS-NPs were B cells. Decreasing the level of polyethylene glycol modification increased the uptake of CWS-NPs by B cells, leading to an increased CTL activity. A comparison of CWS-NPs with different uptake efficiencies into dendritic cells and B cells suggested that the DCs with internalized CWS-NPs may contribute to CTL activation compared with B cells. We succeeded in enhancing CTL activity by the CWS-NPs, and the findings reported herein should provide important information regarding target cells for the development of CWS-NP.

[Development of a Nano DDS for Cancer Immunotherapy Based on Llipid Nanoparticles]

The appearance of immune checkpoint inhibitors has been a major turning point in cancer therapy. The success of immune checkpoint therapy has revolutionized the field of cancer therapy, and immunotherapy has joined the cancer treatment ranks as a pillar. To induce effective anti-tumor immune responses, it is necessary both to enhance the activity of immune cells and to block immune suppression by tumor cells. Carrier type drug delivery systems based on nanobiotechnology (nano DDS) represent a potentially useful technology for efficiently achieving both: enhancement of the activity of immune cells and blocking immune suppression. It has become clear that nano DDS can improve the practical utility of a wide variety of immune functional molecules and thus regulate drug kinetics and intracellular dynamics to improve drug efficacy and reduce side effects. We have been in the process of developing a nano DDS for the enhancement of cancer immunotherapy. A nano DDS encapsulating an agonist of a simulated interferon gene pathway greatly enhanced the activity of the agent's antitumor immune response. To block immune suppression, we successfully developed a small interfering RNA loaded into a nano DDS which regulates gene expression in immune cells. In this review, we summarize our recent efforts regarding cancer immunotherapy using nano DDS.

Barata T, Gaspar M, Brocchini S, Zloh M, Peppas NA, Satchi-Fainaro R, F. Florindo H. α-Galactosylceramide and peptide-based nano-vaccine synergistically induced a strong tumor suppressive effect in melanoma

α-Galactosylceramide (GalCer) is a glycolipid widely known as an activator of Natural killer T (NKT) cells, constituting a promising adjuvant against cancer, including melanoma. However, limited clinical outcomes have been obtained so far. This study evaluated the synergy between GalCer and major histocompatibility complex (MHC) class I and MHC class II melanoma-associated peptide antigens and the Toll-Like Receptor (TLR) ligands CpG and monophosphoryl lipid A (MPLA), which we intended to maximize following their co-delivery by a nanoparticle (NP). This is expected to improve GalCer capture by dendritic cells (DCs) and subsequent presentation to NKT cells, simultaneously inducing an anti-tumor specific T-cell mediated immunity. The combination of GalCer with melanoma peptides and TLR ligands successfully restrained tumor growth. The tumor volume in these animals was 5-fold lower than the ones presented by mice immunized with NPs not containing GalCer. However, tumor growth was controlled at similar levels by GalCer entrapped or in its soluble form, when mixed with antigens and TLR ligands. Those two groups showed an improved infiltration of T lymphocytes into the tumor, but only GalCer-loaded nano-vaccine induced a prominent and enhanced infiltration of NKT and NK cells. In addition, splenocytes of these animals secreted levels of IFN-γ and IL-4 at least 1.5-fold and 2-fold higher, respectively, than those treated with the mixture of antigens and adjuvants in solution. Overall, the combined delivery of the NKT agonist with TLR ligands and melanoma antigens via this multivalent nano-vaccine displayed a synergistic anti-tumor immune-mediated efficacy in B16F10 melanoma mouse model.

STATEMENT OF SIGNIFICANCE

Combination of α-galactosylceramide (GalCer), a Natural Killer T (NKT) cell agonist, with melanoma-associated antigens presented by MHC class I (Melan-A:26) and MHC class II (gp100:44) molecules, and Toll-like Receptor (TLR) ligands (MPLA and CpG), within nanoparticle matrix induced a prominent anti-tumor immune response able to restrict melanoma growth. An enhanced infiltration of NKT and NK cells into tumor site was only achieved when the combination GalCer, antigens and TLR ligands were co-delivered by the nanovaccine.

Development of a Drug Delivery System for Cancer Immunotherapy

Delivery systems are a powerful technology for enhancing the effect of cancer immunotherapy. We have been in the process of developing lipid-based delivery systems for controlling the physical properties and dynamics of immunofunctional molecules such as antigens and adjuvants. The lipid nanoparticulation of these molecules improves their physical properties, resulting in a good water dispensability, greater stability, and small size. The cell wall skeleton of bacille Calmette-Guerin (BCG-CWS) could be used to replace live BCG as a drug for treating bladder cancer, but problems associated with the physical properties of BCG-CWS have prevented its use. To overcome such problems, we developed a novel packaging method that permits BCG-CWS to be encapsulated into lipid nanoparticles, which induce antitumor responses against bladder cancer. Lipid nanoparticulation also improves the intracellular trafficking and biodistribution of immunofunctional molecules. Cyclic di-GMP (c-di-GMP) is an adjuvant that is recognized by the cytosolic sensor. However, c-di-GMP cannot pass through the cell membrane. We encapsulated c-di-GMP into lipid nanoparticles containing a pH-responsive lipid that was developed in our laboratory and achieved efficient cytosolic delivery and the induction of antitumor immunity. Furthermore, we are attempting to control the functions of immune cells by RNA interference. We have recently succeeded in the efficient delivery of small interfering RNA into mouse dendritic cells (DCs), which led to the enhancement of antitumor activity of DCs. In this review, our recent efforts regarding cancer immunotherapy using lipid-based nanoparticles are reviewed.

TWEAK Negatively Regulates Human Dicer

The ribonuclease Dicer plays a central role in the microRNA pathway by processing microRNA precursors (pre-microRNAs) into microRNAs, a class of 19- to 24-nucleotide non-coding RNAs that regulate expression of ≈60% of the genes in humans. To gain further insights into the function and regulation of Dicer in human cells, we performed a yeast two-hybrid (Y2HB) screen using human Dicer double-stranded RNA-binding domain (dsRBD) as bait. This approach identified tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) as a Dicer-interacting protein candidate. Confocal immunofluorescence microscopy revealed the colocalization of Dicer and TWEAK proteins at the perinuclear region of HeLa cells. The Dicer-TWEAK protein interaction was confirmed by coimmunoprecipitation and found not likely to be mediated by RNA. TWEAK dose-dependently reduced pre-microRNA conversion into mature microRNA in Dicer activity assays using extracts of transfected human HEK 293 cells. TWEAK expression also impaired microRNA-guided RNA silencing of a reporter gene induced by a pre-microRNA. These findings suggest a role for TWEAK—a pro-inflammatory cytokine—in regulating Dicer function and microRNA biogenesis, and its possible involvement in regulating gene expression during inflammatory processes and diseases.

Development of a multifunctional envelope-type nano device and its application to nanomedicine

Successful nanomedicines should be based on sound drug delivery systems (DDS) the permit intracellular trafficking as well as the biodistribution of cargos to be controlled. We have been developing new types of DDS that are multifunctional envelope-type nano devices referred to as MENDs. First, we will focus the in vivo delivery of siRNA to hepatocytes using a YSK-MEND which is composed of pH-responsive cationic lipids. The YSK-MEND is capable of inducing efficient silencing activity in hepatocytes and can be used to cure mice that are infected with hepatitis C or B. The YSK-MEND can also be applied to cancer immunotherapy through the activation of immune cells by delivering different compounds such as cyclic-di-GMP, siRNA or alpha-galactosylceramide as a lipid antigen. The findings indicate that, as predicted, these compounds, when encapsulated in the YSK-MEND, can be delivered to the site of action and induced immune activation through different mechanisms. Finally, a MITO-Porter, a membrane fusion-based delivery system to mitochondria, is introduced as an organelle targeting DDS and a new strategy for cancer therapy is proposed by delivering gentamicin to mitochondria of cancer cells. These new technologies are expected to extend the therapeutic area of Nanomedicine by increasing the power of DDS, especially from the view point of controlled intracellular trafficking.