Preparation and evaluation of doxorubicin-luminespib co-loaded multivesicular liposomes

A combinational therapeutic system that simultaneously administrates various pathways is preferred for anti-cancer treatment. In the present study, we successfully constructed a co-delivery system, multivesicular liposomes (MVLs) co-encapsulating doxorubicin (DOX) and luminespib (AUY922). A simple and accurate dual-wavelength spectrophotometric method was established for the determination of DOX and AUY922 in liposomal formulation. MVL-loading drugs were prepared by a multi-emulsion solvent evaporation method, which exhibited excellent physicochemical properties, such as particle size of 3–8 μm and high entrapment efficiency above 95% for DOX and 73% for AUY922. The synergetic cytotoxic effect for these two drugs was evaluated in MDA-MB-231 cells. The in vitro antitumor studies demonstrated the superior anti-proliferation activity of DOX and AUY922 with a combination index of 0.43, indicating a great synergistic effect. The experimental data suggested that combinational use of DOX and AUY922 within liposomes could be an effective way to develop efficient treatments of cancers.     

Preparation,characterization and evaluation of multi-component-loaded liposomes containing Tat-TOS,phospholipase D inhibitor and doxorubicin

In the present study, we aimed to co-load the α-TOS conjugate Tat-TOS with the phospholipase D inhibitor FIPI and the antitumor drug doxorubicin (DOX) in a liposome delivery system for antitumor metastasis. Firstly, Tat-TOS was synthesized by solid-phase synthesis, and its structure was confirmed. The ability of free and liposomal Tat-TOS to induce apoptosis in vitro was evaluated by flow cytometry. Biodistribution of Tat-TOS-loaded liposomes was investigated by a molecular imaging system. Multi-component-loaded liposomes modified with Tat-TOS containing FIPI and DOX was prepared by thin film dispersion method in combination with pH gradient method and post-insertion method. Physicochemical properties were determined, and the in vitro uptake ability of the formulations was evaluated. The results showed that the prepared liposomes were characterized by a uniform particle size distribution and small particle size. The encapsulation efficiency of FIPI and DOX exceeded 85%. Both free and liposomal Tat-TOS significantly improved the activity of inducing apoptosis of tumor cells. The liposomes modified with Tat-TOS were apparently accumulated in normal lung tissue and tumor metastasized lung. Multi-component-loaded liposomes exhibited the strongest cell uptake capacity, suggesting a stronger anti-metastatic effect and anti-tumor activity in vivo.     

漆树酸和阿霉素联合应用抗肝癌的协同作用

目的评价漆树酸与阿霉素联合应用对人肝癌HepG2细胞是否具有协同作用。方法人月十癌HepG2细胞经漆树酸和（或）阿霉素处理后,MTS法检测细胞的增殖情况,Westernblot方法检测Caspase-3,8,9和PARP凋亡相关蛋白的变化。结果漆树酸和阿霉素联合应用能够明显增强抑制HepG2细胞增殖,与单药组相比具有明显的协同作用。漆树酸和阿霉素联合应用可以活化Caspase-3、Caspase-8、Caspase-9,引起PARP的切割。结论漆树酸和阿霉素联合应用具有明显的协同作用,能够增强抑制HepG2细胞的增殖,两药联合作用的机制可能与诱导Caspase系统活化相关。     

Preparation and characterization of liposomal formulations of neurotensin-degrading enzyme inhibitors

Neurotensin-degrading enzyme (NTDE) inhibitors hold great potential for treating psychotic disorders. However, brain uptake of such compounds in vivo is generally low due to the presence of the blood-brain barrier. In this study, liposomal formulations of two NTDE inhibitors, named compound 1 (C1) and compound 2 (C2) were prepared. Association of these compounds with the liposomal bilayer, subsequent liposomal stability, and compound release in the presence of albumin was studied. Entrapment of the compounds in the liposomal bilayer showed the solubilizing properties of the liposomes. Size and polydispersity index of the compound-entrapped liposomes did not change over 1 month, showing colloidal stability of the liposomal drug formulations. The amount of compounds associated with the liposomes decreased within one day. After this, the association remained stable at 4 °C. For C1, association remained stable at 37 °C in HEPES buffered saline, and the compound was gradually released in the presence of bovine serum albumin. For C2, the release was rapid in both HBS and BSA at 37 °C. In conclusion, the formulation of NTDE inhibitors C1 and C2 in liposomes has been demonstrated and holds promise to deliver NTDE inhibitors in vivo.     

肿瘤转移靶向肽修饰的阿霉素脂质体对高转移性乳腺癌细胞的靶向特异性研究

肿瘤转移日渐成为肿瘤治疗的重要靶标。本研究采用肿瘤转移靶向肽（TMT）与脂质材料（PEG-DSPE）偶联获得靶向化合物（TMT-PEG-DSPE）,用以构建靶向阿霉素脂质体（TMT-LS-DOX）。结果表明,TMT-LS-DOX呈现出良好的药剂学性质。选用高转移性乳腺癌细胞（MDA-MB-435S和MDA-MB-231）对该转移特异性递送系统进行评价,采用非转移性乳腺癌细胞（MCF-7）作为对照。游离TMT多肽浓度达100μg/mL时仍未显示出细胞毒性。与MCF-7相比,MDA-MB-435S及MDA-MB-231细胞对TMT-LS-DOX摄取增加,并经受体竞争性实验证明该促进作用由TMT介导。因此,TMT修饰的纳米载体可能成为增加化疗药物对高转移性乳腺癌特异性的一种新策略。     

Preparation and evaluation of liposomal clarithromycin with antimicrobial effect

In this study, we developed a novel liposomal delivery system modified by Tat peptide and wheat germ agglutinin (WGA) with antimicrobial effect. Physicochemical parameters, in vitro antimicrobial, time-kill study, cellular uptake, biofilm formation inhibition and in vivo antibacterial efficacy against Methicillin-resistant Staphylococcus aureus (MRSA) were investigated. Minimum inhibitory concentrations (MICs) and colony-forming units (CFUs) in the time-kill study for Tat-WGA-modified liposomal clarithromycin (CLA-TatWGALip) were lower than those of free and other modified liposomal CLA. Flow cytometry analysis disclosed that TatWGALip delivered more coumarin 6 into bacteria. Furthermore, Tat-WGA-modified liposomal CLA efficiently inhibited the formation of MRSA biofiom. CFU of MRSA in the abscess of mice treated with CLA-TatWGALip was significantly lower than that of any others (P<0.01). Collectively, liposomal delivery system modified by Tat and WGA could be a promising anti-resistant infection strategy.     

Kinetic analysis of tissue distribution of doxorubicin incorporated in liposomes in rats: I.

The purpose of this study was to perform a kinetic analysis of the tissue distribution of doxorubicin (DXR) and liposomes separately after intravenous administration of DXR entrapped in liposomes in rats. Liposomes were double labeled with 14C-DXR (L-DXR) and 3H-inulin (L-INU). Blood and tissues were sampled at specified times until 120 min. Blood clearance of L-DXR was similar to that of L-INU. Distribution of both L-DXR and L-INU into the liver was parallel and extensive, while in the heart, the pattern of distribution differed between L-DXR and L-INU after peak concentration. Time courses of tissue concentration were explained well by dividing tissue into a shallow compartment with efflux and a deep compartment without efflux. In the liver, pharmacokinetic parameters of L-DXR and L-INU were similar, and the two kinetically different compartments may correspond to different uptake processes in hepatic endocytosis. In the heart, the shallow compartment was considered to correspond to the cardiac vascular space, and the intercompartmental rate constant (k3) for L-DXR was much larger than that for L-INU. The estimated half-life for this process was 20 min. The half-life for the degradation of liposomes in blood circulation was also estimated at 20 min from data on the urinary excretion of released 3H-inulin. These results suggest that the release of DXR from liposomes may be the rate-limiting process in the tissue distribution of DXR to the heart.     

Effect of harmine and brain lesions on apomorphine induced motor activity.

Application of harmine (10 mg/kg IP) 30 min before apomorphine decreased the motoric effects of the latter. Following harmine an increase in 5-HT and a decrease in 5-HIAA in different brain regions have been found. Injection of 5,6-DHT into nucleus medianus raphe 7 days before the experiment caused a significant increase of the apomorphine effect. Harmine pretreatment reduced this escessive motility as well as additional lesion of the substantia nigra with 6-OH-DA. Lesion induced by 6-OH-DA alone was without significant effect on the hypermotility following apomorphine. Application of PCPA 3 days before testing elicited an increase of apomorphine-induced hypermotolity which could be abolished by preceding harmine application. The experiments demonstrate the inhibitory effect of the central serotoninergic system on the apomorphine syndrome as well as the serotoninergic-dopaminergic interaction in hypermotility.     

Preparation and characterization of liposomal systems entrapping the boronated compound o-carboranylpropylamine

Boron neutron capture therapy (BNCT) is based on the nuclear reaction that occurs when the stable isotope, Boron-10, is irradiated with low-energy thermal neutrons to yield ionizing Helium and Lithium ions that are highly damaging and usually lethal to cells. The successful treatment of cancer by BNCT requires the selective concentration of Boron-10 within malignant tumours. Liposomes have been used as therapeutic compound delivery vehicles for in vivo application, including several anticancer agents. The ability of the boroncontaining compound, o-carboranylpropylamine chloride, to accumulate within unilamellar liposomes in response to a transmembrane pH gradient is evaluated. Characterization of the systems obtained is performed for conventional and polyethylene glycol (PEG)-modified (stealth) liposomes, in terms of lipid and CPA contents, vesicle size and stability in detergent solutions. Results demonstrate that CPA loading and vesicle stability can be controlled by the experimental procedure. The loading of CPA into liposomes with average diameters of 100nm is estimated at 13000 molecules per vesicle for the most stable systems. CPA toxicity to normal human peripheral blood lymphocytes and to adherent glioblastoma multiforme SK-MG-1 cells in vitro is observed to decrease as a result of the entrapment of CPA in liposomes.     

Ultrasound enhanced antitumor activity of liposomal doxorubicin in mice

Liposomal encapsulation of doxorubicin (DXR) improves tumor accumulation and reduces adverse effects. One possible strategy for further optimization of this delivery technology would be to design the liposome carrier to release its content within the tumor tissue in response to specific stimuli such as ultrasound (US). In this study, the tumor uptake properties and therapeutic efficacy of 1,2 distearoyl-sn-glycero-3-phosphatidylethanolamine-based liposomes containing DXR were investigated in nude mice bearing tumor xenografts. The liposomal DXR formulation alone showed no inhibitory effect on tumor growth. However, upon exposure to low frequency US in situ inhibition of tumor growth was demonstrated.     

新型阿霉素隐形阳离子脂质体的制备及体外细胞实验

目的制备阿霉素隐形阳离子脂质体(DOX-SCL),并与中性脂质体(DOX-SNL)比较在体外小鼠乳腺癌4T1细胞实验上的差异。方法采用薄膜超声法制备空白脂质体,硫酸铵梯度法包载盐酸阿霉素(DOX);引入赖氨酸-胆固醇酯(Chol-lys)制成阳离子脂质体(CL),同时引入聚乙二醇-胆固醇琥珀酸酯(CHEMS-PEG)制成隐形阳离子脂质体(SCL);采用凝胶柱-UV法测定包封率;采用MTT法测定细胞毒性及体外抗肿瘤活性;通过流式细胞试验考察4T1细胞对脂质体的摄取情况。结果 SCL粒径约为100 nm,Zeta电位约为15.2 mV,对DOX的包封率大于95%;CHEMS-PEG的引入可以有效地降低CL的细胞毒性;与DOX-SNL相比,4T1细胞对DOX-SCL的摄取有所增加,DOX-SCL对4T1细胞的抑制率也更高。结论 SCL作为新型药物载体,可有效地促进DOX在肿瘤细胞中的传递。     

Simultaneous analysis of liposomal doxorubicin and doxorubicin using capillary electrophoresis and laser induced fluorescence

A method based on a capillary electrophoresis with laser induced fluorescence detection was developed and validated for simultaneous separation of doxorubicin (DOX) and liposomal encapsulated DOX. The separation was accomplished using a fused silica capillary (60 cm in total length, 75 μm I.D.) and potassium phosphate buffer [12.5 mM, pH 7.4] as the running buffer. The effect of sample preparation conditions on maintaining liposomal integrity was also investigated. The limit of detection for DOX was 0.1 μg/ml and the precision and accuracy of CE/LIF method was within the ranges of FDA guidelines. The validated method was successfully used to quantify DOX in human plasma using a direct injection of a 4-fold dilution of spiked liposomal DOX in human plasma.     

阿霉素修饰纳米银的制备及其体外抗肿瘤活性研究

摘要： 目的 设计合成一类新型的具有pH响应性的阿霉素-纳米银 （DOX-Ag NPs） 联合抗肿瘤药物, 对其理化性质进行表征, 并研究其体外响应性释药行为和抗肿瘤活性。方法 通过硫辛酰肼 （LA-NHNH2 ） 连接纳米银 （Ag NPs） 和阿霉素 （DOX）, 得到DOX-Ag NPs。利用核磁氢谱 （1 H NMR） 和高分辨质谱 （HRMS） 对硫辛酰肼-阿霉素 （LA- NHN=DOX） 进行结构确证; 通过动态光散射 （DLS） 和透射电镜 （TEM） 分析纳米粒的粒径和形貌; 通过紫外-可见吸收光谱和荧光光谱表征纳米粒的光学性质; 通过透析法结合荧光光谱检测DOX-Ag NPs在不同pH下的DOX释放行为; 采用噻唑蓝比色法研究DOX-Ag NPs对HepG2肿瘤细胞的增殖抑制效果。结果 LA-NHN=DOX的1 H NMR数据及HRMS检测到746.275 6处的分子离子峰均证明LA-NHN=DOX成功合成。DOX-Ag NPs为粒径 （40.4±3.8） nm的球形纳米粒; 在弱酸性条件下DOX-Ag NPs能够快速响应性释放DOX; DOX-Ag NPs对HepG2肿瘤细胞增殖抑制呈现浓度依赖性, 当DOX浓度为0.5~20 mg/L （Ag浓度为0.45~18 mg/L） 时, DOX-Ag NPs组细胞生存率均明显低于DOX 组和Ag NPs组 （均P＜0.05）。结论 DOX-Ag NPs是一种具有pH响应性的联合抗肿瘤纳米制剂, 能在肿瘤组织快速释放DOX, 并通过与Ag NPs的协同治疗, 发挥良好的体外抗肿瘤作用。     

镓离子的协同抗菌研究进展

摘要：抗生素的耐药性问题迫切需要研究者开发新的抗菌药物,镓离子因其独特的抗菌方式受到研究者的广泛关注,近年来无论在纳米尺度上的研究还是和其他抗菌材料的结合,镓都表现出优异的抗菌效果。本文综述了近年来镓离子与其他抗菌材料协同抗菌的相关研究进展,其中镓离子与卟啉物质的结合已经受到国外众多学者的广泛研究。目前国内对此类的研究还较少,且国内外的大多数研究还停留在体外研究阶段,临床研究上还有更多的工作要做,未来的研究将会进一步扩大其在体内抗菌的应用和潜力。     

Bone targeting potential of bisphosphonate-targeted liposomes. Preparation, characterization and hydroxyapatite binding in vitro

The main constituent of bone is hydroxyapatite (HAP). Since HAP is only present in 'hard' tissues like bone and teeth, it represents a promising target for the selective drug delivery to bone. Due to the exceptional affinity of bisphosphonates (BP) for HAP, cholesteryl-trisoxyethylene-bisphosphonic acid (CHOL-TOE-BP), a new tailor-made BP derivative, was used as bone targeting moiety for liposomes. CHOL-TOE-BP-targeted liposomes were designed for the treatment of bone-related diseases to achieve prolonged local exposure to high concentrations of the bioactive compounds, thereby enhancing therapeutic efficacy and minimizing systemic side effects. The CHOL-TOE-BP-targeted liposomes were characterized regarding particle size and zeta potential. To study the bone targeting potential of these conjugates, an in vitro HAP binding assay was established. The obtained binding data indicate that CHOL-TOE-BP is useful as targeting device for liposomal drug delivery to bone.     

Disaccharide-modified liposomes and their in vitro intracellular uptake

Sterically stabilized liposomes (SSL) were known to be accumulated passively in cancer due to the effect of enhanced permeability and retention (EPR). However, drug delivery via SSL to cancer seemed to show an insufficient improvement of chemotherapeutic efficacy. Herein, carbohydrate-binding proteins (lectins) of cell surface, which express on the plasmic membrane of many malignant cells, can be a good model of surface-modified liposomes. In this study, we investigated the in vitro characteristics of liposomes of which the surface was modified with a disaccharide molecule, sucrose or maltose. The disaccharide-modified lipids such as sucrose-modified lipid and maltose-modified lipid, in which the disaccharide was conjugated to the one end of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-(polyethylene glycol)-2000 (DSPE-PEG2000), was synthesized. The disaccharide-modified liposomes were prepared by thin film-hydration method and then doxorubicin (DOX), an anticancer drug, was loaded to the prepared liposomes by the remote loading method with ammonium ion gradient. Flow cytometry and confocal microscopy analyses showed that the disaccharide-modified liposomes enhanced the intracellular uptake of liposomes into various cancer cell lines via lectin-mediated endocytosis. The disaccharide-modified liposomes in which DOX was loaded inside of liposomes exhibited higher cytotoxicity against various cancer cells than DOX-loaded SSL did. These results suggest that disaccharide-modified liposomes may be promising cancer targeting carriers which can enhance intracellular uptake and cytotoxicity of the drug-loaded liposomes via lectin-mediated endocytosis.     

Effect simultaneous delivery with P-glycoprotein inhibitor and nanoparticle administration of doxorubicin on cellular uptake and in vitro anticancer activity

Multidrug resistance (MDR) is the most common problem of inadequate therapeutic response in tumor cells. Many trials has been developed to overcome drug efflux by P-glycoprotein (P-gp). For instance, co-administration of a number of drugs called chemosensitizers or MDR modulators with a chemotherapeutic agent to inhibit drug efflux. But for optimal synergy, the drug and inhibitor combination may need to be temporally colocalized in the tumor cells. In this study, we encapsulated the Ver and Dox in PLGA nanoparticles to inhibit the P-gp drug efflux in breast cancer. Moreover, the effect of either Dox solution (Dox_S), Dox nanoparticles (Dox_NP), Dox_S + Ver_S, Dox_NP + Ver_S, Dox_NP + Ver_NP or Dox-Ver_NP was evaluated. It was found that co administration of Dox_NP with Ver_NP (70.76%) showed similar cellular uptake of Dox to Dox/Ver combination solution (70.62%). However it is observed that Dox_NP + Ver_NP has the highest apoptotic activity (early apoptotic 13.52 ± 0.06%, late apoptotic 53.94 ± 0.15%) on human breast adenocarcinoma (MCF 7) cells. Hence, it is suggested that Dox_NP + Ver_NP is a promising administration for tumor therapy.     

Antiproliferative effect of pheophorbide a–mediated photodynamic therapy and its synergistic effect with doxorubicin on multiple drug-resistant uterine sarcoma cell MES-SA/Dx5

Abstract

Prolonged cancer chemotherapy is associated with the development of multidrug resistance (MDR), which is a major cause of treatment failure. Photodynamic therapy (PDT) has been applied as anticancer therapy and a means of circumventing MDR. The antiproliferative effect of pheophorbide a–mediated photodynamic therapy (Pa-PDT) has been demonstrated in several human cancer cell lines, including the uterine sarcoma cell line, MES-SA. This study set out to evaluate, first, the therapeutic potential of Pa-PDT on MES-SA/Dx5 uterine sarcoma cells and, subsequently, the effectiveness of combination therapy using Pa-PDT with doxorubicin (Dox). Our results showed that Pa-PDT was able to circumvent MDR in the P-glycoprotein (P-gp) overexpressing human uterine sarcoma cell line, MES-SA/Dx5. Intracellular accumulation of Pa and Pa-PDT-induced cell death was not abrogated by MDR phenotype, when compared to the parental cell line, MES-SA. Combined therapy using Pa-PDT and Dox, a common chemotherapeutic drug, was found to be synergistic in the cell line, MES-SA/Dx5. Both activity and expression of MDR1 and P-gp were reduced by Pa-PDT treatment and such reductions were attenuated by α-tocopherol, the scavenger of reactive oxygen species (ROS), suggesting that the effect of Pa-PDT was mediated by the generation of intracellular ROS. In conclusion, our findings demonstrated the therapeutic potential of Pa-PDT alone or in combination with Dox in combating multidrug-resistant malignancies.