Liposome is an ideal drug carrier with many advantages such as excellent biocompatibility, non-immunogenicity, and easy functionalization, and has been used for the clinical treatment of many diseases including tumors. For the treatment of tumors, liposome has some passive targeting capability, but the passive targeting effect alone is very limited in improving the drug enrichment in tumor tissues, and active targeting is an effective strategy to improve the drug enrichment. Therefore, active targeting liposome drug-carriers have been extensively studied for decades. In this paper, we review the research progresses on active targeting liposome drug-carriers based on the specific binding of the carriers to the surface of tumor cells, and summarize the opportunities, challenges and future prospects in this field.
Objective To investigate the influence of cationic liposomemediated endostatin gene on colorectal cancer liver metastasis. Methods Animal model for colorectal carcinoma liver metastasis were established. The plasmid expressing endostatin genelipofectAMINE were injected in vein. Results After cationic liposomemediated endostatin gene were injected in vein, the incidence of liver metastasis and mean numbers of liver tumors were decreased, survival time of animal was significantly longer. Conclusion Intravenous injection of cationic liposomemediated endostatin gene can control the development of colorectal cancer liver metastasis effectively.
ObjectiveTo evaluate the therapeutic effect and adverse reaction of paclitaxel liposome combined with continuous infusion of large-dose 5-fluorouracil(5-fu) in treatment for advance gastric cancer(AGC). MethodsFrom May 2009 to August 2012, 63 consecutive patients with AGC in this hospital were enrolled in this study. All the patients were given chemotherapy including paclitaxel liposome and continuous infusion of large-dose(2.5 g/m2) 5-fu. The efficacy and toxicity of this regimen were observed. ResultsThere was no patient who could not tolerate adverse reaction related to such regimen. Five cases achieved complete response and 31 cases achieved partial response, the overall response rate was 57.1%(36/63). Hematologic toxicity included gradeⅢ/Ⅳleucopenia 8 cases(12.7%) and neutropenia 10 cases(15.9%), while there was no occurrence of gradeⅢ/Ⅳanemia or thrombopenia. Non-hematologic toxicity was fairly mild. ConclusionsPaclitaxel liposome is safe, well tolerated, highly targeted, and has long duration of effect. Paclitaxel liposome combined with continuous infusion of large-dose 5-fu is safe and effective in treatment for patients with AGC.
Objective To compare the transfection effects on soluble fms-like tyrosine kinase receptor-1 (sFlt-1) gene (2-4 transcellular region) mediated by carboxymethylated dextran coated nanoparticle and lipofectamineTM2000.Methods The plasmid pcDNA3.1-EGFP/sFlt-1(2-4) was constructed and assessed by enzyme cut, electrophoresis, and genetic sequencing. Three groups were divided: nanoparticle group, lipofectamine group, and non-transfected group. Twenty-four and 48 hours after the transfection, the distribution of cellular green fluorescence was oberved under the inverted phase contrast fluorescence microscope; the expression rate of green fluorescence was measured by flow cytometry; the expression of sFlt-1(2-4)mRNA and the protein was detected by reverse transcriptionpolymerase chain reaction (RT-PCR) and Western blot; the growth of the cells was observed by methyl thiazolyl tetrazolium (MTT) colorimetry and the relative growth rate (RGR) of the cells in each group was calculated; the cellular apoptosis in each group was detected by Hoechst staining.Results The sequence of sFlt-1(2-4) gene was equal to 915 base pair (bp).The transfection rate was 45% in nanoparticle group and 21% in lipofectamine group; the difference between the two groups was significant (t=2.541，Plt;0.05). Forty-eight hours after the transfection, the expression of sFlt-1（2-4）mRNA and protein was obviously higher in nanoparticle group than that in lipofectamine group (t=2.454，2.398；Plt;0.05) . Twenty-four and 48 hours after the transfection,the difference of RGR of the cells between nanoparticle and non-transfected group was not significant（t=1.436，Pgt;0.05）; the RGR in lipofectamine group differed much from that in non-transfected and nanoparticle group (t=2.412，2.545; Plt;0.05) ; the difference of cellular apoptosis was not significant between nanoparticle and nontransfected group (t=1.436，Pgt;0.05), but significant between nanoparticle and lipofectamine group (t=2.236，Plt;0.05). Conclusion The transfection rate of sFlt-1(2-4) mediated by carboxymethylated dextran coated nanoparticle was higher than that mediated by lipofectamineTM2000.
Objective To investigate the inhibitory effect of proliferation cell nuclear antigen (PCNA) antisense oligonucleotides mediated by liposome transfection on hepatocellular carcinoma cell proliferation. MethodsThe antisense oligonucleotides were complementary to 18mer sequences next to the start codon of PCNA mRNA sequences. The human hepatocellular carcinoma cell line Bel7404 was treated with antisense oligonucleotides. The inhibition of proliferation was estimated by MTT method. We compared the deference between the liposome mediated transfection technique and direct transfection technique. ResultsThe cell proliferation was inhibited effectively by antisense oligonucleotides. A sense sequence oligomer showed no effect.Liposome mediated transfection could enhance the inhibitory effect. Conclusion Liposome mediated transfection could enhance the inhibitory effect of PCNA antisense oligonucleotides on hepatocellular carcinoma cell proliferation.
Objective To reviewe the research progress of liposomes as antibiotic carriers. Methods Domestic and abroad literature concerning liposomes as antibiotic carriers was reviewed and analyzed thoroughly. Results Liposomes as antibiotic carriers can significantly improve drug distribution, enhance antibacterial activity, and reduce the side effects of antibiotics during treatment. But it also has some problems, such as poor physical and chemical stabilities and low encapsulation efficiency. Conclusion Liposomes as antibiotic carriers can reduce the drug toxicity, improve drug biodistribution, and pharmacokinetics, and bring the dawn to completely curing infections disease.
Liposomes with precisely controlled composition are usually used as membrane model systems to investigate the fundamental interactions of membrane components under well-defined conditions. Hydration method is the most common method for liposome formation which is found to be influenced by composition of the medium. In this paper, the effects of small alcohol (ethanol) on the hydration of lipid molecules and the formation of liposomes were investigated, as well as its coexistence with sodium chloride. It was found that ethanol showed the opposite effect to that of sodium chloride on the hydration of lipid molecules and the formation of liposomes. The presence of ethanol promoted the formation of liposomes within a certain range of ethanol content, but that of sodium chloride suppressed the liposome formation. By investigating the fluorescence intensity and continuity of the swelled membranes as a function of contents of ethanol and sodium chloride, it was found that sodium chloride and ethanol showed the additive effect on the hydration of lipid molecules when they coexisted in the medium. The results may provide some reference for the efficient preparation of liposomes.
【Abstract】ObjectiveTo construct a recombinant eukaryotic expression vector for human endostatin in order to study the inhibitory effect of liposome-mediated endostatin gene on the growth of human liver carcinoma in nude mice. MethodsHuman endostatin cDNA including IL-2 secreting peptide was cloned into eukaryotic expression plasmid pcDNA3.0 to construct recombinant plasmid pCD-sEndo. pCD-sEndo plasmid was transferred into hepatocarcinoma cell line SMMC-7721 mediated by liposome Dosper, the expression and secretion of endostatin gene was detected by RTPCR and Western blot analysis. The suspension of SMMC-7721 cells was injected subcutaneously at the back of 32 nude mice to establish the model of human liver carcinoma. The mice were divided into 4 groups randomly, and injected with Dosper+pCD-sEndo, Dosper+pcDNA3.0, Dosper and physiological brine separately. Tumor volume was measured by stages. The mice were executed after the drug had been given for 1 week, then the microvessel density (MVD) of the tumor tissue was detected with immunohistochemical method and apoptotic index of tumor cells was measured by TUNEL-stain. ResultsThe eukaryotic expression vector pCD-sEndo was successfully constructed and was confirmed by enzyme digestion and sequence analysis. Expression of endostatin gene was detected in transfected SMMS-7721 cells by RTPCR in vitro, and endostatin protein was also detected in the supernatant of transfected SMMS-7721 cells by Western blot. In vivo study, the growth of human liver carcinoma was inhibited in the group injected with endostatin gene: the average volume of tumor in this group was significantly smaller than that in other groups （P＜0.05）; the average MVD in this group was 6.2±2.5, significantly less than that in the group injected with physiological brine (32.8±6.4), Dosper （27.8±6.4）, or Dosper+pcDNA3.0 (25.5±5.5), P＜0.05. The average apoptotic index of tumor cells in treatment group, brine group, Dosper group and Desper+pcDNA3.0 group was 24.5±7.3, 7.6±2.5, 9.5±3.0 and 11.2±3.6 respectively, it was evidently higher in the treatment group than in the latter three groups. ConclusionHuman endostatin mediated by cation liposome could decrease the microvessel number of implanted human hepatocarcinoma in nude mice. It could also accelerate apoptosis of tumor cells and inhibit growth of tumor.
Objective To investigate the possibility of constructing eukaryotic expression vector for human glial derived neurotrophic factor （hGDNF）, transfecting it to spinal cord tissue of rats so as to treat acute spinal cord injury. Methods The eukaryotic expression vector pcDNA3-hGDNF was constructed by recombinant DNA technique, transfected into glial cell and neuron of spinal cord by liposome DOTAP as experimental group. In control group, mixture of empty vector and liposome was injected. The mRNA and protein expressions of hGNDF were detected by RT-PCR and Western blot. Results After the recombinant eukaryotic expression vector for hGDNF was digested with Hind III and XbaⅠ, electrophoresis revealed 400 bp fragment for hGDNF gene and 5 400 bp fragment for pcDNA3 vector. In the transfected spinal cord tissue, the mRNA and protein expressions of hGDNF gene were detected with RT-PCR and Western blot. Conclusion The constructed eukaryotic expression vector pcDNA3hGDNF could be expressed in the transfected spinal cord tissue of rat, so it provide basis for gene therapy of acute spinal cord injury.
ObjectiveTo study the effect of Triton X-100 promoting liposome-mediated bone morphogenetic protein 2 (BMP-2) gene transfection of rat bone marrow mesenchymal stem cells (BMSCs). MethodsBMSCs were separated and cultured from the femur and tibia of healthy Wistar rats (8-week-old, male). The 3rd passage BMSCs identified by detecting the surface antigen were used to transfect. The optimum concentration of Triton X-100 for liposome mediated gene transfection was determined with ELISA meter by the way of MTT. In optimum concentration of Triton X-100, liposome mediated BMP-2 gene was transfected to BMSCs. The experiment was divided into 3 groups according to types of trasfection agents:BMSCs were transfected with Triton X-100+liposome+BMP-2 (experimental group), with liposome+ BMP-2 (conventional transfection group), and untransfected BMSCs served as blank control group. After 48 hours of transfecting, the green fluorescent protein (GFP) in cells was detected through inverted fluorescence microscope. After 72 hours of transfection, real-time fluorescence quantitative PCR was applied to measure the mRNA expression of BMP-2. Results0.01% Triton X-100 was determined to be the optimum concentration for not only making the BMSCs maintain vitality, but also achieving a certain effect on BMSCs. After trasfecting for 48 hours, GFP was observed through inverted fluorescence microscope in the experimental group and conventional transfection group, but was not observed in the blank control group. After trasfecting for 72 hours, the relative BMP-2 mRNA expression level was 5.94±0.12 in the experimental group, and was 4.99±0.08 in the conventional transfection group, showing significant difference (t=360.28, P=0.02). The transfection efficiency was increased by 19% in the experimental group. Conclusion0.010%Triton X-100 can promote the liposome mediated BMP-2 gene transfection of rat BMSCs, and can improve the transfection efficiency.