Uptake Of Liposomes Research Articles

Enhanced uptake and anti-maturation effect of celastrol-loaded mannosylated liposomes on dendritic cells for psoriasis treatment

Psoriasis is an autoimmune skin disease in which dendritic cells (DCs) trigger the progression of psoriasis by complex interactions with keratinocytes and other immune cells. In the present study, we aimed to load celastrol, an anti-inflammatory ingredient isolated from Chinese herbs, on mannosylated liposomes to enhance DC uptake as well as to induce DC tolerance in an imiquimod-induced psoriasis-like mouse model. Mannose was grafted onto liposomes to target mannose receptors on DCs. The results demonstrated that compared with unmodified liposomes, DCs preferred to take up more fluorescence-labeled mannosylated liposomes. After loading celastrol into mannose-modified liposomes, they effectively inhibited the expression of maturation markers, including CD80, CD86 and MHC-II, on DCs both in vitro and in vivo. Additionally, after intradermal injection with a microneedle, celastrol-loaded mannose-modified liposomes (CEL-MAN-LPs) achieved a superior therapeutic effect compared with free drug and celastrol-loaded unmodified liposomes in the psoriasis mouse model in terms of the psoriasis area and severity index, histology evaluation, spleen weight, and expression of inflammatory cytokines. In conclusion, our results clearly revealed that CEL-MAN-LPs was an effective formulation for psoriasis treatment and suggested that this treatment has the potential to be applied to other inflammatory diseases triggered by activated DCs.

Biomimetic Recognition-Based Bioorthogonal Host–Guest Pairs for Cell Targeting and Tissue Imaging in Living Animals

Biomimetic Recognition-Based Bioorthogonal Host–Guest Pairs for Cell Targeting and Tissue Imaging in Living Animals

Fabrication of aptamer-guided siRNA loaded lipopolyplexes for gene silencing of notch 1 in MDA-mb-231 triple negative breast cancer cell line

Triple negative breast cancer is an aggressive type of cancer with limited therapeutic options. Aptamer-functionalized liposomes to deliver short interference RNAs (siRNAs) offer a promising therapeutic option. The current study aimed at preparing an aptamer functionalized liposome loaded with siRNA-protamine polyplexes for selective delivery of Notch 1 siRNA into cancer cells. The aptamer functionalized liposomes were characterized by Dynamic Light Scattering (DLS) and electron microscopy. In vitro silencing and antiproliferative efficiency were conducted using the triple negative breast cancer cell line MDA-MB-231. The unfunctionalized loaded liposomes had a Z-average size of 153.1 ± 6.481 nm and a charge of −17.5 ± 0.265 mV, while the functionalized liposomes had a higher Z-average size of 285 ± 12.33 nm and a charge of −23.8 ± 0.924 mV with an encapsulation efficiency (EE%) of 60%. The presence of the nucleolin aptamer on the surface of the liposomes increased the cellular uptake of liposomes by almost 2 folds. Confocal images showed the co-localization of liposomes and aptamer in the cytoplasm where the siRNA must be released. The functionalized loaded liposomes produced a higher antiproliferative and silencing effect compared to the unfunctionalized liposomes. In conclusion, this formulation represents a novel promising vehicle to deliver siRNA effectively to the MDA-MB-231 cell line.

Abstract 306: Cationic cholesterol liposomes for combination therapy to treat drug-resistant ovarian cancer

Abstract Introduction: Ovarian cancer is the fifth leading cause of cancer mortality in women, with nearly 75% of women who respond to initial platinum-based chemotherapy experiencing relapse due to drug resistance [1,2]. Liposomes are a promising solution to overcoming drug resistance due to their biocompatibility and capacity to encapsulate hydrophilic and hydrophobic drugs as well as complex small interfering RNA (siRNA), which have the potential to downregulate the expression of genes related to drug resistance [3]. We aim to synthesize and characterize a cationic liposomal system to deliver siRNA and paclitaxel (PTX) to ovarian cancer cells. Methods: Cholesterol (CHOL) liposomes were synthesized by the thin-film hydration method. Dynamic light scattering (DLS) was used to determine the size, polydispersity index (PDI), and zeta potential of the liposomes. Uptake of liposomes into OVCAR3 and OVCAR3-T40, a wild-type and a paclitaxel-resistant human adenocarcinoma cell line, was examined using fluorescence microscopy. The cytotoxicity of unloaded CHOL liposomes was evaluated through MTS assay on OVCAR3 and OVCAR3-T40 cells. Results: PTX- and siRNA-loaded CHOL liposomes had an average diameter of 114.9 ± 10.35 nm and a zeta potential of 27.6 ± 1.79 mV. Blank CHOL liposomes had an average diameter of 123.0 ± 2.49 nm and zeta potential of 32.3 ± 2.16 mV. All formulations of liposomes were cationic and formed monodisperse nanoparticles. The encapsulation efficiency of siRNA and PTX was 99.8% and 80.4% respectively. Coumarin 6, a hydrophobic model drug, was loaded into liposomes to verify cellular uptake through fluorescent imaging. Results demonstrated that the liposomal system was efficiently delivered intracellularly. Blank liposomes were used to determine the toxicity of the delivery system. The unloaded liposomes were not cytotoxic to both the wild-type and drug-resistant cell lines at concentrations up to 75 µg/mL, and therefore, cytotoxicity of drug-loaded liposomes can be attributed to paclitaxel, siRNA, or combination treatment. Conclusions: Liposomes were successfully formed with a monodisperse size, exhibited effective drug and siRNA loading, and were internalized into OVCAR3 and OVCAR3-T40 cells. Future work includes investigating the efficacy of the liposomal system in mediating gene silencing. Acknowledgements: This work was supported in part by the National Science Foundation EPSCoR Program under NSF Award # OIA-1655740 and Clemson Creative Inquiry.

Abstract 1322: Evaluating intracellular accumulation profiles of chemotherapeutic agents using CLENs for the treatment of Y79 retinoblastoma

Abstract Retinoblastoma is the most common intraocular malignancy in children, with approximately 200-300 new cases in the United States each year. Currently, conventional chemotherapy agents (carboplatin, cisplatin, doxorubicin, vincristine, and cyclophosphamide) used to treat retinoblastoma, are rapidly eliminated from circulation. Novel lipid nanoparticles (LNP) have been shown to improve delivery of encapsulated chemotherapeutic agents to Y79 retinoblastoma cells, and therefore the agents are less toxic to healthy cells. Past studies have supported the use of LNP delivery systems to enhance chemotherapeutic drug action against Y79 retinoblastoma cells as well. The experimental plan will now evaluate the use of cellular membrane lipid-extracted nanoliposomes (CLENs) to examine targeting using cellular models of retinoblastoma. Y79 cells were cultured in RPMI growth medium supplemented by 20% FBS. CLENs and lipid extracts (LE) were prepared according to previously published protocols. Following the development of Y79-LE nano-preparations consisting of DOPC, Y79-LE, and cholesterol at different ratios, preparations were evaluated in terms of physicochemical properties and uptake by Y79 cells. The additional inclusion of cationic lipid DOTAP in Y79-LE preparations was evaluated for select preparations. Particle sizes and zeta potential values were determined for each preparation type by ZetaPALS. CLENs exhibited an average particle size between 400 to 600 nm. Experiments with Y79-CLENs prepared in the absence and presence of DOTAP, showed they were taken up by the target cell population. In general, the inclusion of Y79-LE increased cellular uptake. The inclusion of cholesterol in combination with DOTAP showed enhanced liposomal uptake in Y79 retinoblastoma cells. Evidence from previous studies suggest a benefit of using lipid nanoparticles compared to more conventional treatment options. Preliminary findings suggest a positive correlation between the particle size and degree of cellular uptake. Additional optimization studies are currently underway. Citation Format: Nan Luo, Virali Patel, Minesh Patel, Eric Conte, Robert Campbell. Evaluating intracellular accumulation profiles of chemotherapeutic agents using CLENs for the treatment of Y79 retinoblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1322.

A focus on critical aspects of uptake and transport of milk-derived extracellular vesicles across the Caco-2 intestinal barrier model

Bovine milk-derived extracellular vesicles (EVs) hold promises as oral drug delivery systems. Since EV bioavailability studies are difficult to compare, key factors regarding EV uptake and intestinal permeability remain little understood. This work aims to critically study uptake and transport properties of milk-derived EVs across the intestinal barrier in vitro by standardization approaches.Therefore, uptake properties were directly compared to liposomes in intestinal Caco-2 cells. Reliable staining results were obtained by the choice of three distinct EV labeling sites, while non-specific dye transfer and excess dye removal were carefully controlled. A novel fluorescence correction factor was implemented to account for different labeling efficiencies. Both EV and liposome uptake occurred mainly energy dependent with the neonatal Fc receptor (FcRn) providing an exclusive active pathway for EVs. Confocal microscopy revealed higher internalization of EVs whereas liposomes rather remained attached to the cell surface. Internalization could be improved when changing the liposomal formulation to resemble the EV lipid composition. In a Caco–2/HT29–MTX co-culture liposomes and EVs showed partial mucus penetration.For transport studies across Caco–2 monolayers we further established a standardized protocol considering the distinct requirements for EVs. Especially insert pore sizes were systematically compared with 3 µm inserts found obligatory. Obtained apparent permeability coefficients (Papp) reflecting the transport rate will allow for better comparison of future bioavailability testing.

Effects of Protein Source on Liposome Uptake by Cells: Corona Composition and Impact of the Excess Free Proteins.

Corona formation in biological fluids strongly affects nanomedicine interactions with cells. However, relatively less is known on additional effects from the free proteins in solution. Within this context, this study aims to gain a better understanding of nanomaterial-cell interactions in different biological fluids and, more specifically, to disentangle effects due to corona composition and those from the free proteins in solution. To this aim, the uptake of liposomes in medium with bovine and human serum are compared. Uptake efficiency in the two media differs strongly, as also corona composition. However, in contrast with similar studies on other nanomaterials, despite the very different corona, when the two corona-coated liposomes are exposed to cells in serum free medium, their uptake is comparable. Thus, in this case, the observed differences in uptake depend primarily on the presence and source of the free proteins. Similar results are obtained when testing the liposomes on different human cells, as well as in murine cells and in the presence of murine serum. Overall, these results show that the protein source affects nanomedicine uptake not only due to effects on corona composition, but also due to the presence and composition of the free proteins in solution.

HBV Pre-S1-Derived Myristoylated Peptide (Myr47): Identification of the Inhibitory Activity on the Cellular Uptake of Lipid Nanoparticles.

The Myr47 lipopeptide, consisting of hepatitis B virus (HBV) pre-S1 domain (myristoylated 2–48 peptide), is an effective commercialized anti-HBV drug that prevents the interaction of HBV with sodium taurocholate cotransporting polypeptide (NTCP) on human hepatocytes, an activity which requires both N-myristoylation residue and specific amino acid sequences. We recently reported that Myr47 reduces the cellular uptake of HBV surface antigen (HBsAg, subviral particle of HBV) in the absence of NTCP expression. In this study, we analyzed how Myr47 reduces the cellular uptake of lipid nanoparticles (including liposomes (LPs) and HBsAg) without NTCP expression. By using Myr47 mutants lacking the HBV infection inhibitory activity, they could reduce the cellular uptake of LPs in an N-myristoylation-dependent manner and an amino acid sequence-independent manner, not only in human liver-derived cells but also in human non-liver-derived cells. Moreover, Myr47 and its mutants could reduce the interaction of LPs with apolipoprotein E3 (ApoE3) in an N-myristoylation-dependent manner regardless of their amino acid sequences. From these results, lipopeptides are generally anchored by inserting their myristoyl residue into the lipid bilayer and can inhibit the interaction of LPs/HBsAg with apolipoprotein, thereby reducing the cellular uptake of LPs/HBsAg. Similarly, Myr47 would interact with HBV, inhibiting the uptake of HBV into human hepatic cells, while the inhibitory effect of Myr47 may be secondary to its ability to protect against HBV infection.

Molecular docking and dynamic studies of a potential therapeutic target inhibiting glyoxalase system: Metabolic action of the 3, 3 '- [3- (5-chloro-2-hydroxyphenyl) -3-oxopropane-1, 1-diyl] - Bis-4-hydroxycoumarin leads overexpression of the intracellular level of methylglyoxal and induction of a pro-apoptotic phenomenon in a hepatocellular carcinoma model

Methylglyoxal is a dicarbonyl compound recruited as a potential cytotoxic marker, initially presents in cells and considered as a metabolite of the glycolytic pathway. Our aim is to demonstrate the inhibitory effect of 3, 3'-[3-(5-chloro-2-hydroxyphenyl)-3-oxopropane-1, 1-diyl] Bis (4-hydroxycoumarin) on the glyoxalase system, and indirectly its anticancer activity. The docking of OT-55 was conducted by using Flexible docking protocol, ChiFlex and libdock tools inside the active site of Glo-I indicated that both hydrogen bonding and hydrophobic interactions contributed significantly in establishing potent binding with the active site which is selected as a strong inhibitor with high scoring values and maximum Gibbs free energy. Coumarin-liposome formulation was characterized and evaluated in vivo against chemically induced hepatocarcinoma in Wistar rats. After Diethylnitrosamine (DEN) induction, microscopic assessment was realized; precancerous lesions were developed showing an increase of both tumor-associated lymphocyte and multiple tumor acini supported by the blood investigation. Our finding also suggested a preferential uptake of liposomes respectively in liver, kidney, lung, brain and spleen in the DEN-treated animals. OT-55 has also been shown to inhibit the activity of Glo-I in vitro as well as in DEN-treated rats. An abnormal high level of MGO of up to 50% was recorded followed by a reduction in glucose consumption and lactate dehydrogenase production validated in the positive control. MGO generates apoptosis as depicted by focal hepatic lesions. Also, no deleterious effects in the control group were observed after testing our coumarin but rather a vascular reorganization leading to nodular regenerative hyperplasia. Involved in the detoxification process, liver GSH is restored in intoxicated rats, while no changes are seen between controls. At the endothelial cell, OT-55 appears to modulate the release of NO only in the DEN-treated group. OT-55 would behave both as an anticancer agent but also as an angiogenic factor regarding results obtained.

A Dual pH-Responsive DOX-Encapsulated Liposome Combined with Glucose Administration Enhanced Therapeutic Efficacy of Chemotherapy for Cancer.

BackgroundThe acidic microenvironment of cancer can promote tumor metastasis and drug resistance. Acidic tumor microenvironment-targeted therapy is currently an important means for treating tumors, inhibiting metastasis, and overcoming drug resistance. In this study, a dual pH-responsive DOX-encapsulated liposome (DOPE-DVar7-lip@DOX) was designed and fabricated for targeting the acidic tumor microenvironment. On the one hand, the response of acid-sensitive peptide (DVar7) to the acidic tumor microenvironment increased the uptake of liposomes in tumors and prolonged the retention time; on the other hand, the response of acid-sensitive phospholipid (DOPE) to the acidic tumor microenvironment improved the controlled release of DOX in tumors.MethodsThe acid-sensitive peptide DVar7 modified liposomes can be obtained by simple incubation of DSPE-DVar7 with DOX-loaded DOPE liposomes (DOPE-lip@DOX). The tumor targeting of the dual pH-responsive liposome was investigated in vitro and in vivo by near-infrared fluorescence imaging. The tumor therapeutic efficacy of DOPE-DVar7-lip@DOX was evaluated in breast cancer mouse model using the traditional liposome as a control. Moreover, we regulated the tumor microenvironment acidity by injecting glucose to further enhance the therapeutic efficacy of cancer.ResultsDVar7 can allosterically insert into the tumor cell membrane in the acidic tumor microenvironment to enhance the tumor uptake of liposomes and prolong the retention time of liposomes in tumor. In addition, the therapeutic efficacy of pH-responsive liposomes can be further enhanced by glucose injection regulating the acidity of tumor microenvironment.DiscussionDVar7 modified acid-sensitive nanocarriers combined with acidity regulation have great potential to improve drug resistance in clinical practice, thus improving the response rate and therapeutic effect of chemotherapy.

Macrophage membrane-mediated targeted drug delivery for treatment of spinal cord injury regardless of the macrophage polarization states

Targeted delivery of therapeutics for spinal cord injury (SCI) has been a long-term challenge due to the complexity of the pathological procession. Macrophage, as an immune cell, can selectively accumulate at the trauma site after SCI. This intrinsic targeting, coupled with good immune-escaping capacity makes macrophages an ideal source of biomimetic delivery carrier for SCI. Worth mentioning, macrophages have multiple polarization states, which may not be ignored when designing macrophage-based delivery systems. Herein, we fabricated macrophage membrane-camouflaged liposomes (RM-LIPs) and evaluated their abilities to extend drug circulation time and target the injured spinal cord. Specially, we detected the expression levels of the two main targeted receptors Mac-1 and integrin α4 in three macrophage subtypes, including unactivated (M0) macrophages, classically activated (M1) macrophages and alternatively activated (M2) macrophages, and compared targeting of these macrophage membrane-coated nanoparticles for SCI. The macrophage membrane camouflage decreased cellular uptake of liposomes in RAW264.7 immune cells and strengthened binding of the nanoparticle to the damaged endothelial cells in vitro. RM-LIPs can prolong drug circulation time and actively accumulate at the trauma site of the spinal cord in vivo. Besides, RM-LIPs loaded with minocycline (RM-LIP/MC) showed a comprehensive therapeutic effect on SCI mice, and the anti-pyroptosis was found to be a novel mechanism of RM-LIP/MC treatment of SCI. Moreover, the levels of Mac-1 and integrin α4 in macrophages and the targeting of RM-LIP for SCI were found to be independent of macrophage polarization states. Our study provided a biomimetic strategy via the biological properties of macrophages for SCI targeting and treatment.

Transdermal Penetrating Peptide Conjugated Liposomes as Drug Delivery Carrier Comprising Macromolecules

: The aim of the study was to investigate a system using liposomes and cell penetrating peptides (CPP) for optimal transdermal delivery of macromolecules. Typical DOPE liposomes were prepared with lipid mixture (DOPE:PC:Chol = 1.5:1.5:2.0, molar ratio) and active materials (Rhodamine B; MW ~480 and Dextran-RITC; MW ~10,000). CPP-conjugated DOPE liposomescontaining active materials were prepared by conjugating the peptide to DOPE liposomes (DOPE:PC:Chol:DSPE-PEG-Mal = 1.5:1.1:2.0:0.2 or 0.4, molar ratio). Physical properties of both liposomes were evaluated, including particle size and zeta potential. The particle sizes of typical liposome and CPP-DOPE liposome were approximately 100 nm, and the zeta potential values of both liposomes were approximately -25mV and over +11mV respectively. Moreover, cellular uptake efficiency was assessed by flow cytometry (FACS). CPP-conjugated liposomes resulted higher cellular uptake efficiency compared to typical DOPE liposomes, showing higher fluorescent intensity in CPP-DOPE liposomes. In confocal laser scanning microscope (CLSM) studies, both cellular uptake and skin permeation were visually estimated. In the case of Rhodamine B, having a relatively small molecular weight,absorption into the cell was successful, and showed the highest rate of cellular uptake with CPP-DOPE liposomes. Dextran-RITC, a macromolecule with a relatively bigger molecular weight, showed similar results to Rhodamine B. In terms of skin permeation, CPP-DOPE liposomes containing Rhodamine B showed noticeable skin absorption after 4 and 18 hours, and the permeation range was wider and thicker than that with typical liposomes. For Dextran-RITC, with typical DOPE liposome, it was hardly permeable through the skin, but with CPP-DOPE liposomes, on the other hand, the skin permeations after 4 and 18 hours were remarkable. The improved cellular uptake and skin permeation of the CPP-conjugated liposomes are due to the cationic arginine-rich peptide. In vivo studies also proved that the CPP-conjugated liposomes are superior in depigmentation and anti-wrinkle studies than typical liposomes. These results demonstrate that the CPP-conjugated liposomes could also be effective for transdermal drug delivery of antioxidant and anti-aging therapeutics.

In vitro anticancer activity of Nε-acyl lysine methyl ester through folate receptor targeted liposomes

Delivering anticancer drugs to tumor tissues with high specificity to realize minimal adverse effects is currently the main research focus of cancer treatment. Nε-acyl lysine methyl esters (Nε-lys) have the potential to serve as novel and safe anticancer agents owing to their pH-responsive membrane-disruptive activity and non-toxic metabolic products. In this study, we synthesized three Nε-lys with different hydrophobic chain lengths and evaluated their cytotoxicity to cancer and normal cells. One of the compounds with an acyl chain of 14 carbon atoms (MKM) showed moderate cytotoxicity and was delivered to cancer cells encapsulated in liposomes (MKM-LP). We additionally modified the liposomes with folate and PEG as a cancer-targeting drug delivery system (FA-PEG-MKM-LP) to enhance the cell selectivity. We tested the difference in the cellular uptake of liposomes between a folate receptor-positive human ovarian cancer cell line (SKOV3) and a healthy human ovary epithelial cell line (IOSE). The experimental results showed that FA-PEG-MKM-LP had low cytotoxicity to IOSE and higher cancer-targeting ability than other tested liposomes. Fluorescence imaging of dead cells and a LDH release assay further demonstrated that the cytotoxicity of FA-PEG-MKM-LP possessed time- and dose-dependent activity and specificity to cancer cells. These results lay a foundation for the development of Nε-lys as a promising anticancer drug.

99mTc Stearyl 6-(benzylidenehydrazinyl) nicotinamide Liposomes as Tumor Permeability Evaluation Tracer.

Nanomedicine is a highly demanded discipline. Liposomes have seen an increased attention due to their physicochemical properties that allow them to act as nanocarriers of drugs and also of radioisotopes that can be used to diagnose and treat cancer. In order to obtain a novel permeability cancer imaging agent based on 99mTc-labeled liposomes, we describe microwave-assisted synthesis of stearyl 6-(benzylidenehydrazinyl) nicotinamide lipid, which was included in two formulations: nanometric hydrazinonicotinic acid (HYNIC) liposome and its PEGylated coated analogue, HYNIC-PEG liposome. Radiolabeling with 99mTc via stearyl 6-(benzylidenehydrazinyl) nicotinamide was found to be easy, reproducible, and stable, revealing high radiochemical purity (94 ± 1.7%) for both liposomal formulations. Biodistribution at 4 h and 24 h and scintigraphic images at 4 h were performed in normal and melanoma-bearing C57BL/6 mice. Biodistribution studies at 4 h showed tumor uptake of 99mTc-HYNIC liposome and 99mTc-HYNIC-PEG liposome (1.1 ± 0.6 and 2.5 ± 0.4, respectively) and also at 24 h p.i. (1.8 ± 0.5 and 3.0 ± 1.1, respectively). Scintigraphic images showed appreciable tumor uptake in melanoma tumor-bearing mice with both liposomal formulations. Our results show that 99mTc stearyl 6-(benzylidenehydrazinyl) nicotinamide liposomes can be used as diagnostic noninvasive in vivo tumor-targeting agents capable of evaluating tumor permeability and development who can be used in personalized chemotherapy planning.

An in vitro evaluation of antitumor activity of sirolimus-encapsulated liposomes in breast cancer cells.

Design and examine the effect of sirolimus-PEGylated (Stealth) liposomes for breast cancer treatment. In this study, we developed conventional and Stealth liposome nanoparticles comprising of distearoylphosphatidylcholine (DSPC) or dipalmitoyl-phosphatidylcholine (DPPC) and DSPE-MPEG-2000 lipids loaded with sirolimus as an anticancer agent. The effect of lipid grade, drug loading and incubation times were evaluated. Particle size distribution, encapsulation efficiency of conventional and Stealth liposomes were studied followed by cytotoxicity evaluation. The cellular uptake and internal localisation of liposome formulations were investigated using confocal microscopy. The designed Stealth liposome formulations loaded with sirolimus demonstrated an effective in vitro anticancer therapy compared with conventional liposomes while the length of the acyl chain affected the cell viability. Anticancer activity was found to be related on the drug loading amounts and incubation times. Cell internalization was observed after 5 h while significant cellular uptake of liposome was detected after 24 h with liposome particles been located in the cytoplasm round the cell nucleus. Sirolimus Stealth liposomes induced cell apoptosis. The design and evaluation of sirolimus-loaded PEGylated liposome nanoparticles demonstrated their capacity as drug delivery carrier for the treatment of breast cancer tumours.

Liposome induction of CD8+ T cell responses depends on CD169+ macrophages and Batf3-dependent dendritic cells and is enhanced by GM3 inclusion

Cancer vaccines aim to efficiently prime cytotoxic CD8+ T cell responses which can be achieved by vaccine targeting to dendritic cells. CD169+ macrophages have been shown to transfer antigen to dendritic cells and could act as an alternative target for cancer vaccines. Here, we evaluated liposomes containing the CD169/Siglec-1 binding ligand, ganglioside GM3, and the non-binding ligand, ganglioside GM1, for their capacity to target antigens to CD169+ macrophages and to induce immune responses. CD169+ macrophages demonstrated specific uptake of GM3 liposomes in vitro and in vivo that was dependent on a functional CD169 receptor. Robust antigen-specific CD8+ and CD4+ T and B cell responses were observed upon intravenous administration of GM3 liposomes containing the model antigen ovalbumin in the presence of adjuvant. Immunization of B16-OVA tumor bearing mice with all liposomes resulted in delayed tumor growth and improved survival. The absence of CD169+ macrophages, functional CD169 molecules, and cross-presenting Batf3-dependent dendritic cells (cDC1s) significantly impaired CD8+ T cell responses, while B cell responses were less affected. In conclusion, we demonstrate that inclusion of GM3 in liposomes enhance immune responses and that splenic CD169+ macrophages and cDC1s are required for induction of CD8+ T cell immunity after liposomal vaccination.

Delivery of the Radionuclide 131I Using Cationic Fusogenic Liposomes as Nanocarriers.

Liposomes are highly biocompatible and versatile drug carriers with an increasing number of applications in the field of nuclear medicine and diagnostics. So far, only negatively charged liposomes with intercalated radiometals, e.g., 64Cu, 99mTc, have been reported. However, the process of cellular uptake of liposomes by endocytosis is rather slow. Cellular uptake can be accelerated by recently developed cationic liposomes, which exhibit extraordinarily high membrane fusion ability. The aim of the present study was the development of the formulation and the characterization of such cationic fusogenic liposomes with intercalated radioactive [131I]I− for potential use in therapeutic applications. The epithelial human breast cancer cell line MDA-MB-231 was used as a model for invasive cancer cells and cellular uptake of [131I]I− was monitored in vitro. Delivery efficiencies of cationic and neutral liposomes were compared with uptake of free iodide. The best cargo delivery efficiency (~10%) was achieved using cationic fusogenic liposomes due to their special delivery pathway of membrane fusion. Additionally, human blood cells were also incubated with cationic control liposomes and free [131I]I−. In these cases, iodide delivery efficiencies remained below 3%.

Delivery of Rapamycin by Liposomes Synergistically Enhances the Chemotherapy Effect of 5-Fluorouracil on Colorectal Cancer.

BackgroundRapamycin is a promising agent for treating tumors, but clinical applications of rapamycin are limited due to its poor water solubility and low bioavailability. This paper constructs a liposome delivery system for rapamycin to improve the effect in treating colorectal cancer.MethodsWe prepared the rapamycin liposomes using the ethanol injection method. The cellular uptake and biodistribution were detected by LC-MS and in vivo imaging system. MTT assay, transwell migration experiment, flow cytometry, and Western blot analysis evaluated the antitumor effect of rapamycin liposomes in vitro. Furthermore, HCT-116 tumor-bearing mice were used to assess the therapeutic efficacy of rapamycin liposomes in vivo.ResultsThe prepared rapamycin liposomes had a particle size of 100±5.5 nm and with a narrow size distribution. In vitro cellular uptake experiments showed that the uptake of rapamycin liposomes by colorectal cells was higher than that of free rapamycin. Subsequently, in vivo imaging experiments also demonstrated that rapamycin liposomes exhibited higher tumor accumulation. Therefore, the ability of rapamycin liposomes to inhibit tumor proliferation, migration and to induce tumor apoptosis is superior to that of free rapamycin. We also demonstrated in vivo good antitumor efficacy of the rapamycin liposomes in HCT-116 xenograft mice. In addition, rapamycin liposomes and 5-FU can synergistically improve the efficacy of colorectal cancer via the Akt/mTOR and P53 pathways.ConclusionCollectively, rapamycin liposomes are a potential treatment for colorectal cancer, as it not only improves rapamycin’s antitumor effect but also synergistically enhances 5-FU’s chemotherapy effect.

Enhanced cellular uptake and cytotoxicity of vorinostat through encapsulation in TPGS-modified liposomes

Vorinostat (VOR) is known as one of the histone deacetylase inhibitors (HDACi) for cancer treatment, and the FDA approves it for cutaneous T cell lymphoma therapy. Poor solubility, permeability, and less anti-cancer activity are the main challenges for the effective delivery of VOR against various cancers. So, our team assumed that the surface-coated liposomes might improve the physicochemical properties of biopharmaceutics classification system class IV drugs such as VOR. The present study aimed to enhance the cytotoxicity and improve cellular uptake using TPGS-coated liposomes in breast cancer cells. Liposomes were fabricated by the film hydration following the probe ultra-sonication method. OR-LIPO and TPGS-VOR-LIPO showed an average particle size of 211.97 ± 3.42 nm with PDI 0.2168 ± 0.006 and 176.99 ± 2.06 nm with PDI 0.175 ± 0.018, respectively. TPGS-coated liposomes had better stability and revealed more than 80 % encapsulation efficiency than conventional liposomes. Transmission electron microscopy confirmed the TPGS coating around liposomes. Moreover, TPGS-coated liposomes enhanced the solubility and showed sustained release of VOR over 48 h. DSC and PXRD analysis also reveal an amorphous state of VOR within the liposomal formulation. MTT assay result indicates that the superior cytotoxic effect of surface-modified liposomes contrasts with the conventional and free VOR solution, respectively. Fluorescence microscopy and flow cytometry results also presented an enhanced cellular uptake of TPGS-coated liposomes against breast cancer cells, respectively. The current investigation's final results declared that TPGS-coated liposomes are promising drug carriers for the effective delivery of hydrophobic drugs for cancer therapy.

Sulfatide-Rich Liposome Uptake by a Human-Derived Neuroblastoma Cell Line

Liposomes are bilayer membrane vesicles that can serve as vehicles for drug delivery. They are a good alternative to free drug administration that provides cell-targeted delivery into tumors, limiting the systemic toxicity of chemotherapeutic agents. Previous results from our group showed that an astrocytoma cell line exhibits selective uptake of sulfatide-rich (SCB) liposomes, mediated by the low-density lipoprotein receptor (LDL-R). The goal of this study was to assess the uptake of liposomes in a neuroblastoma cell line. For this purpose, we used two types of liposomes, one representing a regular cell membrane (DOPC) and another rich in myelin components (SCB). An astrocytoma cell line was used as a control. Characterization of liposome uptake and distribution was conducted by flow cytometry and fluorescence microscopy. Similar levels of LDL-R expression were found in both cell lines. The uptake of SCB liposomes was higher than that of DOPC liposomes. No alterations in cell viability were found. SCB liposomes were located near the cell membrane and did not colocalize within the acidic cellular compartments. Two endocytic pathway inhibitors did not affect the liposome uptake. Neuroblastoma cells exhibited a similar uptake of SCB liposomes as astrocytoma cells; however, the pathway involved appeared to be different than the hypothesized pathway of LDL-R clathrin-mediated endocytosis.