透明质酸修饰载紫杉醇靶向脂质体抑制脑肿瘤干细胞的初步评价

目的:制备透明质酸修饰载紫杉醇(paclitaxel,PTX)靶向脂质体(HALP-PTX),考察其对脑胶质瘤肿瘤干细胞的亲和力和抑制效果。方法:采用薄膜分散法制备HALP-PTX,细胞摄取实验研究胶质瘤干细胞对脂质体的摄取。MTT实验研究不同紫杉醇药物对肿瘤干细胞的增殖抑制率。构建原位移植瘤动物模型,考查不同脂质体对荷瘤裸鼠的生存期的影响。结果:肿瘤干细胞对HALP的摄取能力显著大于普通脂质体(LP),脑肿瘤干细胞对经透明质酸修饰的脂质体的摄取效率是普通脂质体的2.8倍,差异有统计学意义(P<0.01);HALP-PTX对肿瘤干细胞的生长的抑制作用显著强于LP-PTX,HALP-PTX能够显著延长荷瘤裸鼠的中位生存期,生理盐水组、PTX组、LP-PTX组和HALP-PTX组的中位生存期分别为19,23,29,41 d。结论:与PTX以及LP-PTX相比,HALP-PTX能够更加有效的被脑肿瘤干细胞识别和摄取,抑制肿瘤细胞的增殖,具有更强的抗肿瘤作用。     

RGD肽修饰重组高密度脂蛋白载药纳米粒的制备和表征以及肿瘤细胞对其摄取作用

目的：制备和表征RGD肽修饰的重组高密度脂蛋白（RGD—rHDL）载药纳米粒,考察肿瘤细胞对其摄取作用。方法：合成RGD与载脂蛋白AI（ApoAI）的偶联物（RGD—ApoAI）,并以藤黄酸（GA）作为模型药物,采用薄膜分散法制得GA脂质体（LP—GA）,再将RGD—ApoAI与LP—GA共孵育,制备载有GA的RGD—rHDL纳米粒（RGD—rHDL—GA）;随后,对RGD—rHDL—GA进行表征,且采用荧光标记示踪法,通过RGD—rHDL-香豆素-6来考察人肝癌细胞HepG2对载药RGD—rHDL纳米粒的摄取作用。结果：制备的RGD—rHDL—GA呈现规则圆整的类球形,粒径分布均一[（110,70±3．25）nm],Zeta电位为（-39．21±0．10）mV,包封率为（92．20±0．28）％,载药量为（9．03±0．75）％,且其体外释药缓慢,稳定性良好;RGD—rHDL-香豆素-6的肿瘤细胞摄取率明显高于rHDL-香豆素-6。结论：rHDL经RGD修饰后可有效促进所载药物进入肿瘤细胞,提高其肿瘤靶向性。     

RGD肽修饰的异长春花碱-粉防己碱脂质体的制备及体外抑瘤作用研究

目的:制备RGD肽修饰的异长春花碱(VRB)-粉防己碱(TET)脂质体,研究其对脑胶质瘤C6细胞的抑制作用。方法:采用薄膜分散法和硫酸铵梯度法制备RGD肽修饰的VRB-TET脂质体,观察其形态和粒径分布,测定其中VRB的含量;以磺酰罗丹明B法分别测定空白靶向脂质体、VRB普通脂质体和RGD肽修饰的VRB-TET脂质体对C6细胞的抑制作用。结果:所制RGD肽修饰的VRB-TET脂质体呈圆球状或类圆球状,表面光滑,粒径为120 nm左右,其中VRB的平均含量为28.27μg/m L(RSD=0.38%,n=3)。空白靶向脂质体对C6细胞生长无显著影响;RGD肽修饰的VRB-TET脂质体能明显抑制C6细胞生长,其作用后细胞存活率明显低于VRB普通脂质体(P<0.05)。结论:成功制得RGD肽修饰的VRB-TET脂质体,其具有明显的抑制C6细胞生长的作用。     

脑靶向性紫杉醇脂质体的制备与靶向性研究

目的:为达到靶向治疗脑胶质瘤的目的,制备具有脑靶向功能的紫杉醇脂质体。方法:以卵磷脂和两亲性材料PL-GA-PEG为脂质体材料,同时在其表面引入靶向基团(angiopep),利用纳米沉淀的方法制备紫杉醇脂质体,借用尼罗红荧光探针分子检测紫杉醇脂质体被脑胶质瘤细胞U87MG的摄取情况,而后应用MTT检测法测定其对U87MG细胞增殖的影响。结果:所制备的紫杉醇脂质体的具有纳米级结构,纳米颗粒的大小为100nm左右,经荧光成像发现,靶向性的紫杉醇脂质体比非靶向性紫杉醇脂质体更容易被U87MG细胞摄取,相比于其他的紫杉醇药物形式,靶向性紫杉醇脂质体对U87MG细胞的IC50值明显降低(相对于PTX降低3.4倍,相对于NP-PTX降低3.8倍)。结论:紫杉醇脂质体适合作为体内运输的药物载体材料,其对脑胶质瘤细胞U87MG具有一定的靶向性,且靶向性的紫杉醇脂质体对U87 MG细胞的增殖具有强的抑制作用,有望用于脑部疾病的靶向性治疗。     

RVG29修饰脂质体对脑胶质瘤靶向性的初步研究

目的 研究一种新型配体RVG29修饰脂质体后,对体外脑胶质瘤的靶向性.方法 采用有机相合成法制备DSPE-PEG2000-RVG29 PPP(D-RVG29)材料,按照薄膜分散法制备脂质体,通过C6细胞和Hela细胞的细胞摄取考察D-RVG29修饰脂质体后,对体外脑胶质瘤的靶向性.结果 在脂质体处方中加入DSPE-PEG2000-OME(D-OME)可使D-RVG29修饰脂质体具有更好的粒径和分布范围,C6细胞对D-RVG29修饰脂质体的摄取强于未修饰D-RVG29的脂质体,Hela细胞对两种脂质体的摄取强度无明显区别.结论 D-OME可以提高D-RVG29修饰脂质体的稳定性,D-RVG29修饰脂质体具有体外脑胶质瘤细胞的靶向性.     

双配体修饰的阿霉素脂质体靶向于脑胶质瘤的体外研究

目的筛选和优化转铁蛋白、叶酸共同修饰的阿霉素脂质体的处方及制备工艺,以期得到具有良好的脑胶质瘤靶向治疗作用的给药系统。方法采用薄膜分散和硫酸铵梯度法制备阿霉素脂质体。将叶酸连接至二硬脂酸磷脂酰乙醇胺-聚乙二醇2000(DSPE-PEG2000-NH2)得到DSPE-PEG2000-Folic,考察不同磷脂种类、药脂比、水化介质和载药时间,对脂质体粒径、包封率和稳定性的影响,确定脂质体的处方工艺。以大鼠的脑毛细血管内皮细胞(bEnd3)和星形胶质细胞组成体外血脑屏障(blood-brain barrier,BBB),并结合大鼠胶质瘤C6细胞,构建体外模拟胶质瘤靶向治疗的复合BBB模型。考察阿霉素脂质体在bEnd3细胞中的摄取机制和透过BBB的转运速率及对C6细胞的毒性。结果确定了DSPC作为主要磷脂组分,并以120 mmol.L 1的硫酸铵作为水化介质,药脂比为1∶1 5,载药时间选择60 min,成功制备了高包封率和稳定性的双配体脂质体。其在bEnd3细胞中摄取远大于普通脂质体(P<0.05),摄取过程受网格蛋白和小窝内陷介导的细胞内吞作用,并受转铁蛋白和叶酸的影响;同时其在BBB模型中的药物透过速率、及其进一步透过BBB后对下层C6细胞的毒性,均显著高于其他脂质体组。结论转铁蛋白和叶酸共同修饰的阿霉素脂质体具有较好的体外脑胶质瘤靶向治疗作用。     

RGD修饰紫杉醇脂质体的制备及其肺癌靶向治疗研究

目的:制备RGD修饰载紫杉醇(paclitaxel,PTX)脂质体(RGDLP-PTX),研究其理化性质,并探究其肺癌靶向治疗作用。方法:采用薄膜分散法制备RGDLP-PTX。荧光分光光度法研究A549细胞和NCI-H446细胞对普通脂质体(LP)和RGD修饰脂质体(RGDLP)的摄取效率。噻唑蓝实验研究不同紫杉醇浓度对A549细胞和NCI-H446细胞的细胞毒性;流式细胞仪检测RGDLP-PTX对A549细胞和NCI-H446细胞的凋亡诱导作用。用A549细胞构建肺癌裸鼠异位肿瘤模型,研究RGDLP-PTX的体内抗肿瘤作用。结果:RGDLP-PTX的粒径为(106.3±15.2)nm,电位为(6.23±2.2)mV;A549细胞对RGDLP-PTX的摄取效率是LP-PTX的4.4倍,差异有统计学意义(P<0.01);NCI-H446细胞对RGDLP-PTX的摄取效率是LP-PTX的3.8倍,差异有统计学意义(P<0.01);RGDLP-PTX对A549细胞和NCI-H446细胞的增殖抑制率具有浓度依赖性;在相同紫杉醇浓度下,RGDLP-PTX对A549细胞和NCI-H446细胞的增殖抑制率显著强于LP-PTX和游离紫杉醇,差异有统计学意义(P<0.01);RGDLP-PTX,LP-PTX和游离紫杉醇诱导肺癌A549细胞的凋亡率分别为48.3%,27.4%和35.5%,与生理盐水组比较,差异有统计学意义(P<0.01);NCI-H446细胞凋亡率分别为41.3%,22.8%和34.1%,与生理盐水组比较,差异有统计学意义(P<0.01)。RGDLP-PTX,LP-PTX和游离紫杉醇对肺癌肿瘤的抑制率分别为69.3%,47.5%和24.4%,差异有统计学意义(P<0.01)。结论:RGD修饰载紫杉醇脂质体能够高效抑制肺癌细胞的增殖和肿瘤的生长,是一种有效的肺癌靶向给药系统。     

pH敏感多肽修饰载紫杉醇脂质体的制备及评价

目的制备p H敏感多肽修饰载紫杉醇脂质体(p HS-LP-PTX),并评价其体外性质。方法采用薄膜分散法制备PHS-LP-PTX,MTT实验考察脂质体对MCF-7细胞和Hep G2细胞的毒性,通过细胞摄取实验考察脂质体与肿瘤细胞的结合能力。结果所制备的p HS-LP-PTX在p H6.4时平均粒径为125.5±13.4 nm,Zeta电位为10.47±2.53 m V,24 h内具有良好的血清稳定性。MTT结果显示:p H6.4时,p HS-LP-PTX的细胞毒性优于各对照组。体外细胞摄取实验表明:p H6.4时,MCF-7细胞和Hep G2细胞对p HS-LP-PTX的摄取效率优于p H7.4时和普通脂质体。结论紫杉醇脂质体经过p H敏感多肽修饰后,能增强脂质体在酸性环境下的细胞穿透能力,是一种良好的p H敏感型肿瘤靶向给药系统。     

穿膜肽TAT和脑肿瘤靶向肽T7双修饰脂质体的制备和体外靶向性评价

本文旨在制备T7肽和穿膜肽TAT双修饰的脂质体(T7 and TAT dual modified liposomes,T7-TAT-LIP)用于血脑屏障和脑肿瘤细胞双级靶向药物递送。研究以CFPE为荧光探针,T7修饰的PEG-DSPE、TAT修饰的PEG-DSPE、卵磷脂、PEG-DSPE和胆固醇为材料,采用成膜水化法制备脂质体,对T7浓度、TAT浓度、连接T7和TAT的PEG长度进行优化,表征其粒径、zeta电位、形态和稳定性。以b End.3细胞和C6细胞为模型,考察T7-TAT-LIP的细胞摄取能力,表征其穿过血脑屏障和脑肿瘤细胞靶向能力。结果表明,T7用量为脂质的6%、修饰T7所用PEG链长为2000、TAT用量为脂质的0.5%、修饰TAT所用PEG链长为1000时所得到的双修饰脂质体被C6细胞摄取能力最强。优化后T7-TAT-LIP粒径为118 nm,zeta电位为-6.32 m V,透射电镜下形态圆整。脂质体在PBS中较为稳定,37℃放置24 h,浊度和粒径无明显变化;4~8℃放置1个月,粒径和PDI无明显变化。在不同时间点,b End.3和C6细胞摄取T7-TAT-LIP的强度均高于单配体修饰脂质体,且随着孵育时间提高,摄取浓度逐渐提高。这些结果说明,双修饰脂质体具有血脑屏障和脑肿瘤细胞双级靶向能力,且效果优于单配体修饰脂质体。     

RGD修饰的多柔比星脂质体的制备及荷瘤动物活体成像研究

目的制备精氨酸-甘氨酸-天冬氨酸环状三肽(arginine-glycin-aspartic acid,RGD)序列修饰的多柔比星(doxorubicin,DOX)脂质体(RGD-DOX-LP),考察其粒径、zeta电位、包封率,并探究其肿瘤细胞摄取率及在荷瘤裸鼠中的靶向分布情况。方法采用薄膜分散法制备RGD-DOX-LP及多柔比星脂质体(DOX-LP)。荧光分光光度法研究SUP-M2细胞对RGD-DOX-LP,DOX-LP及DOX溶液的摄取效率。以Cyp790为染料,采用近红外小动物活体成像仪研究比较Cyp靶向脂质体(Cyp-RGDDOXLP)与Cyp常规脂质体(Cyp-DOX-LP)在荷瘤裸鼠体内的分布情况。结果 RGD-DOX-LP粒径为(117±1.8)nm,zeta电位为(-12.46±0.86)mv。细胞摄取实验结果显示,SUP-M2细胞对RGDDOXLP的摄取率是DOX-LP的2.8倍,差异有统计学意义(P<0.05)。在荷瘤裸鼠中,Cyp-RGDDOXLP组在肿瘤部位的荧光强度显著高于Cyp-DOX-LP组,荧光持续时间也显著延长。结论 RGD修饰载多柔比星的脂质体能够高效、靶向性地富集于肿瘤组织,是一种有效的抗肿瘤给药系统。     

Liposome formulated with TAT-modified cholesterol for improving brain delivery and therapeutic efficacy on brain glioma in animals

The treatment of central nervous system diseases such as brain glioma is a major challenge due to the presence of the blood-brain barrier (BBB). A cell-penetrating peptide TAT (AYGRKKRRQRRR), which appears to enter cells with alacrity, was employed to enhance the delivery efficiency of normal drug formulation to the brain. Targeting liposomal formulations often apply modified phospholipids as anchors. However, cholesterol, another liposomal component more stable and cheaper, has not been fully investigated as an alternative anchor. In our study, TAT was covalently conjugated with cholesterol for preparing doxorubicin-loaded liposome for brain glioma therapy. Cellular uptake by brain capillary endothelial cells (BCECs) and C6 glioma cells was explored. The anti-proliferative activity against C6s confirmed strong inhibitory effect of the liposomes modified with doxorubicin-loaded TAT. The bio-distribution findings in brains and hearts were evident of higher efficiency of brain delivery and lower cardiotoxic risk. The results on survival of the brain glioma-bearing animals indicate that survival time of the glioma-bearing rats treated with TAT-modified liposome was much longer than in the other groups. In conclusion, the potency of the TAT-modified liposome to enter the BBB appears to be related with the TAT on the liposome's surface. The TAT-modified liposome may improve the therapeutic efficacy on brain glioma in vitro and in vivo.     

CLA-PTX对黑色素瘤B16-F10的体内外抗肿瘤作用

本研究旨在探索CLA-PTX对黑色素瘤B16-F10细胞的体内外抗肿瘤作用。选择鼠源B16-F10细胞系作为研究模型。研究CLA-PTX体外细胞毒,细胞凋亡,细胞周期作用,以及CLA-PTX体外细胞摄取作用。用荷瘤C57BL6/N小鼠研究CLA-PTX的体内抗肿瘤作用。体外细胞毒研究结果表明：CLA-PTX的IC50为（4.25±0.43）μM,优于紫杉醇（6.70±0.80）μM（P〈0.01）。与空白组和紫杉醇组相比,CLA-PTX可使细胞总凋亡比例增加（P〈0.01）。与空白对照组相比,CLA-PTX将细胞周期阻滞于S期,而紫杉醇则使细胞在G2‐M期蓄积。CLA-PTX的细胞摄取量显著高于紫杉醇（P〈0.01）。体内抗肿瘤药效显示,CLA-PTX抗肿瘤活性显著高于空白对照组和紫杉醇组（P〈0.01或P〈0.05）。上述结果表明,CLA-PTX对B16-F10细胞有显著体内外抗肿瘤作用。     

他莫昔芬介导脂质体细胞内化的机制研究

文献报道他莫昔芬能够增强载药脂质体的细胞摄取,其具体机制仍有待研究,有研究者推测此现象是由他莫昔芬抑制P-糖蛋白对药物的外排作用而造成的。本研究为进一步阐明该作用的机理,制备了PEG修饰、共包载他莫昔芬的P-糖蛋白底物阿霉素脂质体及非底物香豆素-6脂质体,研究了不同P-糖蛋白表达水平的细胞对载药脂质体的摄取情况,及包载他莫昔芬后脂质体与脂膜的相互作用。结果表明,共包载他莫昔芬能显著提高所选三种细胞对阿霉素脂质体的摄取,且摄取增加水平与P-糖蛋白表达水平相关。同时,共包载他莫昔芬能显著增加非P-糖蛋白底物香豆素-6脂质体的摄取,对阿霉素脂质体在P-糖蛋白表达阴性的Hela细胞中的摄取也有显著促进作用。表面等离子共振技术证明他莫昔芬脂质体与模型生物膜的亲和力强于不载药的空白脂质体,等温滴定量热技术证明游离他莫昔芬与模型生物膜有明显亲和作用。综上,他莫昔芬能够增强脂质体和生物膜的亲和力,通过抑制P-糖蛋白对药物的外排、提高脂质体和细胞膜的结合两方面的共同作用提高细胞对脂质体的摄取。     

Lipid-albumin nanoassemblies co-loaded with borneol and paclitaxel for intracellular drug delivery to C6 glioma cells with P-gp inhibition and its tumor targeting

Successful chemotherapy with paclitaxel (PTX) is impeded by multidrug resistance (MDR) in tumor cells. In this study, lipid-albumin nanoassemblies co-loaded with borneol and paclitaxel (BOR/PTX LANs) were prepared to circumvent MDR in C6 glioma cells. The physiochemical properties including particle size, encapsulation efficiency and morphology were evaluated in vitro. Quantitative and qualitative investigations of cellular uptake were carried out in C6 glioma cells. The cytotoxicity of the BOR/PTX LANs was determined by MTT assay. After that, the tumor targeting was also evaluated in C6 glioma bearing mice by in vivo imaging analysis. BOR/PTX LANs have a higher entrapment efficiency (90.4 ± 1.2%), small particle size (107.5 ± 3.2 nm), narrow distribution (P.I. = 0.171 ± 0.02). The cellular uptake of PTX was significantly increased by BOR/PTX LANs compared with paclitaxel loaded lipid-albumin nanoassemblies (PTX LANs) in quantitative research. The result was further confirmed by confocal laser scanning microscopy qualitatively. The cellular uptake was energy-, time- and concentration-dependent, and clathrin- and endosome/lysosome-associated pathways were involved. The BOR/PTX LANs displayed a higher cytotoxicity agaist C6 glioma cells in comparion with PTX LANs and Taxol. Moreover, the encapsulation of BOR in LANs obviously increased the accumulation of the drug in tumor tissues, demonstrating the tumor targeted ability of BOR/PTX LANs. These results indicated that BOR/PTX LANs could overcome MDR by combination of drug delivery systems and P-gp inhibition, and shown the potential for treatment of gliomas.     

MPP+和6-羟基多巴胺对C6胶质瘤细胞摄取谷氨酸的影响

目的：研究1-甲基4-苯基-吡啶离子(MPP^ )和6-羟基多巴胺(6-OHDA)对C6胶质瘤细胞摄取谷氨酸(Glu)的影响。方法：应用放射免疫法测定C6胶质瘤细胞对培养液中[^3H]-D，L-谷氨酸的摄取；应用四氮唑(MTY)比色法检测胶质瘤细胞的活性。结果：6-OHDA和MPP^ 均不同程度地抑制C6胶质瘤细胞摄取Glu；6-OHDA显抑制C6胶质瘤细胞活性，而MPP^ 却不影响细胞活性；蛋白激酶C(PKC)激动剂TPA显增强C6细胞对Glu的摄取，并拮抗：MPP^ 对C6细胞摄取Glu的抑制。结论：6-OHDA抑制C6胶质瘤细胞对Glu的摄取，可能与其抑制细胞活性有关，而MPP^ 的抑制作用可能与直接影响转运体的摄取功能有关，并可能由PKC途径介导。     

Inhibitory effects of 1-methyl-4-phenylpyridinium on glutamate uptake into cultured C6 glioma cells

INTRODUCTION Glutamate is a predominant excitatory neurotrans-mitter in the mammalian central neuron system[1]. En-hanced glutamatergic activity is implicated in the pa-thology of neurological diseases, such as Parkinson dis-ease (PD)[1]. PDis characterized by a progressive andselective loss of dopaminergic neurons in substantianigra pars compacta (SNpc) which is the site of a glialactivation in PD. Regulation of glutamate level in thesynaptic cleft by glutamate transporters loca…     

RGD-modified PEG–PAMAM–DOX conjugates: In vitro and in vivo studies for glioma

This work was based on our recent studies that a promising conjugate, RGD-modified PEGylated polyamidoamine (PAMAM) dendrimer with doxorubicin (DOX) conjugated by acid-sensitive cis-aconityl linkage (RGD-PPCD), could increase tumor targeting by binding with the integrin receptors overexpressed on tumor cells and control release of free DOX in weakly acidic lysosomes. To explore the application of RGD-PPCD to glioma therapy, the effects of the conjugate were further evaluated in glioma model. For comparative studies, DOX was also conjugated to PEG–PAMAM by acid-insensitive succinic linkage to produce the PPSD conjugates, which was further modified by RGD to form RGD-PPSD. In vitro cytotoxicity of the acid-sensitive conjugates against C6 cells was higher than that of the acid-insensitive ones, and further the modification of RGD enhanced the cytotoxicity of the DOX-polymer conjugates as a result of the increased cellular uptake of the RGD-modified conjugates by C6 cells. In vivo pharmacokinetics, biodistribution and antitumor activity were investigated in an orthotopic murine model of C6 glioma by i.v. administration of DOX-polymer conjugates. In comparison with DOX solution, all the conjugates showed significantly prolonged half-life and increased AUC and exhibited higher accumulation in brain tumor than normal brain tissue. Although RGD-PPCD was more than 2-fold lower tumor accumulation than RGD-PPSD, it exhibited the longest survival times among all treatment groups, and therefore, RGD-PPCD conjugate provide a desirable candidate for targeted therapy of glioma.