In vitro investigation of RGD-modified stabilized cationic liposomes as non-viral vehicle for siRNA delivery

In this study, the novel RGD-modified stabilized cationic liposomes were developed as the delivery vehicle for siRNA targeting human MDR1 gene. The complex of cationic liposomes and siRNA, RGD-Lipo-siRNA, was prepared with a narrow size distribution below 200 nm. It was shown that the encapsulated siRNA in the liposomes could be effectively protected from serum degradation. Also, enhanced cell binding and intracellular uptake of siRNA in the doxorubicin-resistant human ova- rian cancer cell lines SKOV3/A were found in RGD-Lipo-siRNA preparation as compared to that of unmodified cationic lipsomes （Lipo-siRNA）. Using the post-insertion method for RGD modification, lysosome release of siRNA in pRGD-Lipo-siRNA was improved. From flow cytometry, significant increase of doxorubicin accumulation was observed in the SKOV3/A cells treated with pRGD-Lipo-siRNA targeting human MDR1 gene. In vitro cytotoxicity assay showed that the significant cell growth inhibition was achieved in the SKOV3/A cells after treating with the combined use of siRNA and doxorubicin. In conclusions, postinserted RGD modified lipoplex, pRGD-Lipo-siRNA, was successfully used for siRNA transfection and achieved drug resistance reversal in human ovarian cancer SKOV3/A （doxorubicin-resistant） cells. It suggested that this liposomes might be a potential vehicle for siRNA delivery in vivo.

Hepatocytes targeting of cationic liposomes modified with soybean sterylglucoside and polyethylene glycol

AIM： In this study, a hepatocyte-specific targeting technology was developed by modifying cationic liposomes with soybean sterylglucoside （SG） and polyethylene glycol （PEG） （C/SG/ PEG-liposomes）. METHODS： The liposomal transfection efficiencies in HepG2 2.2.15 cells were estimated with the use of fluorescein sodium （FS） as a model drug, by flow cytometry. The antisense activity of C/SG/PEG-liposomes entrapped antisense oligonucleotides （ODN） was determined as HBsAg and HBeAg in HepG2 2.2.15 cells by ELISA. The liposome uptake by liver and liver cells in mice was carried out after intravenous injection of 3H-labeled liposomes. RESULTS： C/SG-liposomes entrapped FS were effectively transfected into HepG2 2.2.15 cells in vitro. C/SG/PEG-Iiposomes entrapped ODN, reduced the secretion of both HBsAg and HBeAg in HepG2 2.2.15 cells when compared to free ODN. After in vivo injection of ^3H-labeled C/SG/PEG-liposomes, higher radiation accumulation was observed in the hepatocytes than non-parenchymal cells of the liver. CONCLUSION： C/SG/PEG-liposomes mediated gene transfer to the liver is an effective gene-delivery method for hepatocytes-specific targeting, which appears to have a potential for gene therapy of HBV infections.

Effects of pegylated cationic liposomes on siRNA transfection

This study aimed to investigate the effects of cationic liposomes containing different cationic lipids （DC-Chol and DOTAP） and different pegylation ratios on siRNA transfection in human U251 glioma cells. The data showed that the transfection efficiency of DOTAP was much higher than that of DC-Chol and PEG at 2 mol% enhanced cellular uptake of siRNA. Cationic liposome-siRNA complexes with particle size around 100 nm were prepared. PEG modification could efficiently stabilize the liposome in the presence of serum, which might protect the siRNA from serum degradation and prolong the circulation time in vivo. Efficient intracellular uptake and lysosome release of siRNA in human U251 glioma cells were observed for pegylated DOTAP-based lipososomes compared with the control transfection reagent lipofectamine 2000. The results demonstrated that this cationic liposome might be a potential vehicle for the in vivo delivery of siRNA.

Controlled release and antibacterial activity of nanofibers loaded with basil essential oil-encapsulated cationic liposomes against Listeria monocytogenes

In recent years,the development of functional packaging from natural active compounds has been a promising strategy for microbial control in foods.In this study,the basil essential oil(BEO)was applied as the principal antibacterial agent,and a controlled-release nanofibrous system was engineered with responsiveness to bacterial phospholipase.It indicated that encapsulation by cationic liposome significantly improved the dispersity and stability of BEO during the electrospinning process,and the prepared BEO-loaded cationic liposomes(BCLs)could maintain structural integrity in polymer nanofibers.The resulting BCLs-loaded nanofibers showed an effective antibacterial activity against L.monocytogenes.Additionally,it is worth noting that incorporation of soybean lecithin in nanofiber substrate could accelerate the release of loaded antibacterial agents when exposed to L.monocytogenes,thus obtaining an enhanced antibacterial activity.This could be attributed to the increased sensitivity of nanofibers to the degradation by bacterial phospholipases after incorporation with soybean lecithin.Finally,the application test showed that the prepared antibacterial nanofibrous mats could help maintain the quality of chilled pork during 4-days storage,which indicated their promising potential as active packaging.Given the serious threat of L.monocytogenes to food safety,the present antibacterial nanofibers have wide application prospect for improving microbial safety of chilled meat.

Optimization of preparation process of cationic liposome nanoparticles containing Survivin-siRNA and osthol

Objective:To prepare cationic liposome nanoparticles loaded with survivin-siRNA and Cnidium monnieri based on the ability of liposomes to contain both water-soluble and lipid soluble components.Methods:The preparation technology of Osthol cationic liposomes was optimized by orthogonal test with membrane material ratio,drug lipid ratio,ultrasonic time and steaming temperature as factors.The volume ratio of HA-siRNA to protamine and the ratio of HA-siRNA protamine complex to liposome were investigated by control variable method with potential and particle size as indexes.The particle size and zeta potential were measured by potentiometric particle size analyzer,and the shape was observed by transmission electron microscope;The absorbance of different concentrations of FAM-Survivin-siRNA standard solution was measured by microplate analyzer,and the entrapment efficiency of cationic liposomes loaded with FAM-Survivin-siRNA and osthole was calculated.Results:The optimum preparation conditions of osthole loaded cationic liposomes were as follows:the ratio of membrane to material was 3:1,the ratio of drug to lipid was 1:5,the steaming temperature was 30℃,the ultrasonic time was 70 min,and the encapsulation efficiency was 78.34%.The optimum preparation conditions of osthole loaded cationic liposomes loaded FAM-Survivin-siRNA were as follows:the volume ratio of Survivin-siRNA to protamine was 1:1,Protamine complex 25μg.Add 50μL cationic liposomes.The particle size is 132.3±0.2nm,zeta potential is 43.15±0.05mv,and its shape is irregular round;According to the standard curve,the entrapment efficiency of cationic liposome nanoparticles co loaded with Survivin-siRNA and osthole was 81.34±0.041%.Conclusion:The prepared cationic liposome nanoparticles loaded with Survivin-siRNA and osthole have good encapsulation efficiency,particle size and zeta potential.

Cationic Liposome-mediated bcl-xl Gene Transfection into Human Keratocytes

The efficiency and safe range of LipofectamineTM2000 (LF2000)/bcl-xl applied in human keratocytes, the optimal ratio of LF2000/bcl-xl and the bcl-xl gene expression in human keratocytes were investiaged. By using trypan-blue staining, the effects of LF2000 and bcl-xl on the survival rate of the cultured human keratocytes were measured respectively. By using semi-quantitative RT-PCR, the efficiency and the expression of LF2000-mediated bcl-xl transfection into keratocytes were examined. The results showed that the survival rate of human keratocytes had no signficant change in the presence of LF2000 (20 μg/ml) or bcl-xl (10 μg/ml) for 24 h. LF2000 could effectively mediate the transfection of exogenous gene bcl-x1 into human keratocytes. The best transfection efficiency could be obtained when the ratio of bcl-xl/LF2000 was 1:8. One day after transfection, the positive cells for bcl-x1 could be detectable, and the positive rate reached the peak on the post-transfection day 3 (48.3 %), then gradually decreased. Fifteen days after transfection, there were few positive cells. It was suggested that LF2000 could effectively transfer the exogenous gene bcl-xl into human keratocytes without obvious toxicity during a concentration range. LF2000/bcl-xl may be likely to play an important role in gene therapy of human keratocytes.

Delivery of Plasmid DNA into Tumors by Intravenous Injection of PEGylated Cationic Lipoplexes into Tumor-Bearing Mice

For systemic injection of cationic liposome/plasmid DNA (pDNA) complexes (cationic lipoplexes), polyethylene glycol (PEG)-modification (PEGylation) of lipoplexes can enhance their systemic stability. In this study, we examined whether intravenous injection of PEGylated cationic lipoplexes into tumor-bearing mice could deliver pDNA into tumor tissues and induce transgene expression. PEGylation of cationic liposomes could prevent their agglutination with erythrocytes. However, when PEGylated cationic lipoplexes were injected intravenously into tumor-bearing mice, they accumulated in tumor vascular vessels and did not exhibit transgene expression in tumors with both poor and well-developed vascularization. Furthermore, PEGylated cationic lipoplexes of CpG- free pDNA could not increase transgene expression in tumors after intravenous injection. These results suggested that PEGylation could not extravasate cationic lipoplexes from vascular vessels in tumors and abolished transgene expression although it enhanced the systemic stability of cationic lipoplexes by avoiding interactions with blood components such as erythrocytes. Successful delivery of pDNA to tumors by PEGylated cationic liposomes will require a rational strategy and the design of liposomal delivery systems to overcome the issue associated with the use of PEG.

Simultaneous enhancement of cellular and humoral immunity by the lymph node-targeted cholesterolized TLR7 agonist liposomes

Toll-like receptor(TLR)agonists,as promising adjuvants and immunotherapeutic agents,have the potential to enhance immune responses and modulate antigen-dependent T-cell immune memory through activation of distinct signaling pathways.However,their clinical application is hindered by uncontrolled systemic inflammatory reactions.Therefore,it is imperative to create a vaccine adjuvant for TLR receptors that ensures both safety and efficacy.In this study,we designed lymph node-targeted cholesterolized TLR7 agonist cationic liposomes(1V209-Cho-Lip^(+))to mitigate undesired side effects.Co-delivery of the model antigen OVA and cholesterolized TLR7 agonist facilitated DC maturation through TLR activation while ensuring optimal presentation of the antigen to CD8^(+)T cells.The main aim of the present study is to evaluate the adjuvant effectiveness of 1V209-Cho-Lip^(+)in tumor vaccines.Following immunization with 1V209-Cho-Lip^(+)+OVA,we observed a pronounced"depot effect"and enhanced trafficking to secondary lymphoid organs.Prophylactic vaccination with 1V209-Cho-Lip^(+)^(+)OVA significantly delays tumor development,prolongs mouse survival,and establishes durable immunity against tumor recurrence.Additionally,1V209-Cho-Lip^(+)+OVA,while used therapeutic tumor vaccine,has demonstrated its efficacy in inhibiting tumor progression,and when combined with anti-PD-1,it further enhances antitumor effects.Therefore,the co-delivery of antigen and lymph node-targeted cholesterolized TLR7 agonist shows great promise as a cancer vaccine.

Sodium alginate coating simultaneously increases the biosafety and immunotherapeutic activity of the cationic mRNA nanovaccine

The extraordinary advantages associated with mRNA vaccines,including their high efficiency,relatively low severity of side effects,and ease of manufacture,have enabled them to be a promising immunotherapy approach against various infectious diseases and cancers.Nevertheless,most mRNA delivery carriers have many disadvantages,such as high toxicity,poor biocompatibility,and low efficiency in vivo,which have hindered the widespread use of mRNA vaccines.To further characterize and solve these problems and develop a new type of safe and efficient mRNA delivery carrier,a negatively charged SA@DOTAP-mRNA nanovaccine was prepared in this study by coating DOTAP-mRNA with the natural anionic polymer sodium alginate(SA).Intriguingly,the transfection efficiency of SA@DOTAP-mRNA was significantly higher than that of DOTAP-mRNA,which was not due to the increase in cellular uptake but was associated with changes in the endocytosis pathway and the strong lysosome escape ability of SA@DOTAP-mRNA.In addition,we found that SA significantly increased the expression of LUC-mRNA in mice and achieved certain spleen targeting.Finally,we confirmed that SA@DOTAP-mRNA had a stronger antigen-presenting ability in E.G7-OVA tumor-bearing mice,dramatically inducing the proliferation of OVA-specific CLTs and ameliorating the antitumor effect.Therefore,we firmly believe that the coating strategy applied to cationic liposome/mRNA complexes is of potential research value in the field of mRNA delivery and has promising clinical application prospects.

Cationic liposome-mediated transfection of CD40 ligand gene inhibits hepatic tumor growth of hepatocellular carcinoma in mice

Objective: To evaluate the efficacy of cationic liposome-mediated CD40 ligand (CD40L) gene therapy for hepato- cellular carcinoma. Methods: 1×106 of parental H22 cells or H22 cells transfected with the expression vector containing murine CD40L cDNA encoding the entire coding region (pcDNA3.1+-mCD40L) were inoculated subcutaneously into the left flanks of syngenic BALB/C mice. The tumor-bearing mice (tumor nodules 10 mm in maximal diameter) received the treatment of the intratumoral injection of pcDNA3.1+-mCD40L/Transfectam, pcDNA3.1+, or phosphate-buffered saline (PBS), or no treatment. The mice were monitored for tumor growth weekly. We examined mCD40L messenger ribonucleic acid (mRNA) expression by reverse transcription polymerase chain reaction (RT-PCR) and the histologic changes in tumors at two weeks after intratumoral injection using immunohistochemical staining of tumor tissues. Results: All mice inoculated with parental H22 cells developed a tumor subcutaneously, and the tumor size increased progressively within three weeks. However, the mice receiving H22-CD40L cells exhibited complete regression of the tumor two weeks after tumor cell inoculation. The tumor-bearing animals with the treatment of pcDNA3.1+ or PBS, or without treatment had progressive tumor growth, while those mice treated with pcDNA3.1+-mCD40L exhibited a significant inhibition of tumor growth. RT-PCR analysis showed that 783-bp fragments cor- responding to the mCD40L mRNA were amplified only from pcDNA3.1+-mCD40L treated tumors. The tumor samples from pcDNA3.1+-mCD40L-treated mice showed significant lymphocyte infiltration, apoptotic bodies, and confluent necrosis in the tumor tissues. Conclusion: The tumorigenicity of CD40L-expressing cells was abrogated when the cells were implanted subcu- taneously. In vivo gene therapy of established liver tumor nodules in mice by the intratumoral injection of pcDNA3.1+-mCD40L led to significant tumor inhibition. There was mCD40L mRNA expression in the tissues from pcDNA3.1+-mCD40L-treated tumors. The intratumoral injection of pcDNA3.1+-mCD40L induced a strong inflammatory, mainly lymphocytic infiltration of the tumor, and increased the necrotic rate of the neoplastic cells.

Enhanced Survivin siRNA Delivery Using Cationic Liposome Incorporating Fatty Acid-modified Polyethylenimine

We described a novel approach for survivin fatty acid-modified polyethylenimine. A linoleic acid siRNA cellular delivery via a cationic liposome incorporating derivative of branched polyethylenimine（PEI, Mw=25 kDa）, PEI-LA, was synthesized and incorporated into the liposome. The properties of the liposome, cytotoxicity, cellular uptake of cancer cells for survivin siRNA, survivin protein downregulation levels were investigated. PEl-modified liposome showed a lower cytotoxicity and delivered survivin siRNA into HeLa cells and A549 cells efficiently com- pared with PEI-25kDa.