载5-氟尿嘧啶两亲多糖纳米粒的制备及其对肝癌细胞HepG2的杀伤作用

背景与目的:生物可降解载药纳米微粒作为新型药物靶向传输和缓释/控释载体,可延长药物的生物半衰期,减轻药物的毒副作用,而且具有良好的生物相容性。本实验制备可生物降解的载5-氟尿嘧啶(5-fluorouracil,5-FU)葡聚糖接枝聚乳酸共聚物(5-FU/DEX-g-PLA),探讨其对人肝癌细胞HepG2的体内外杀伤作用。方法:利用分子自组装技术制备5-FU/DEX-g-PLA载药纳米微粒,透射电镜观察纳米粒形态,分光光度法计算载药率,MTT法观察对HepG2细胞的体外杀伤作用,动物实验观察其体内抑瘤效应。结果:5-FU/DEX-g-PLA纳米微粒呈球形,粒径约50nm,药物包封率约9.3%。体内药物代谢动力学数据显示,5-FU纳米制剂在血液中维持时间长于5-FU裸药;MTT结果显示,5-FU纳米组细胞生长抑制率(58.8%)与5-FU裸药组(58.0%)差异无显著性(P>0.05);体内抑瘤实验显示,5-FU纳米组肿瘤抑制率(73.1%)显著高于5-FU裸药组(57.5%)。结论:5-FU/DEX-g-PLA纳米微粒可有效抑制肝癌细胞的生长。     

去甲斑蝥素纳米控释制剂抗肿瘤的实验研究

目的 研究不溶于水的抗癌药物去甲斑螯素纳米控释静脉注射制剂的制备工艺及其体内抗肿瘤作用。方法 以聚乳酸－聚乙醇共聚物（PLGA）作为基质材料,采用超声乳化／溶剂挥发法制备PLGA包载去甲斑蝥的纳米级微粒（NP）,对PLGA－去甲斑螯素－NP进行表征,借助扫描电镜观察微粒形态,通过激光光散射实验测定纳米微粒的粒径分布;利用高效液相色谱（HPLC）测定纳米微粒制剂的载药率及体外释放曲线;以MTT方法做体外杀伤癌细胞实验;进行两种肿瘤瘤谱在不同剂量、给药频度及制剂工艺条件下体内抑瘤实验;委托完成动物急性生试验。结果 经电镜观察PLCA－去甲斑螯素－NP为表面光滑的球形微粒,粒径分布平均值是126．4nm, 呈正态分布,PLGA－去甲斑螯素－NP载药率为36．3％;体外释放实验提示,7天可释放出所载60％左右的药物,12天基本释放完全,没有显著的爆破释放;体内抑瘤实验表明：控释制剂间隔给药 疗效已优于未包载药物每日给药的疗效,量－效关系明显,且毒性低,经静脉途径试用无任何不良反应。结论：PLGA纳米粒子可以作为抗肿瘤药物去甲斑螯素的有效载体,并可成功制备其静脉注射剂型,发挥药物更佳的抗肿瘤作用。     

聚乳酸载药纳米微粒制备及其释药效能

背景与目的:医用纳米微粒作为药物传递和控释的载体,是一种新型的控释体系。它与微米粒子的主要区别是超微小体积,能穿过组织间隙并被细胞摄取,可通过毛细血管壁和血脑屏障,因而作为一种新的控释体系而被广泛研究。本研究拟制备聚乳酸纳米微粒,并对其表面形貌、粒径分布、微粒结构、表面元素、体外释放等微粒性能进行应用评估。方法:以可溶性聚乳酸为载体,5鄄氟尿嘧啶(5鄄fluorouracil,5鄄FU)为模型药物,采用超声乳化法制备聚乳酸载纳米微粒,通过电子显微镜观察纳米粒外形结构,用X射线光电能谱仪(X鄄rayphotoelectronspectroscopy,XPS)测定纳米微粒表面元素,用紫外分光光度计测纳米粒载药量和包封率,并测定体外释放量。结果:聚乳酸载纳米微粒呈规则球形,平均粒径(191±17)nm,载药量为15.2%,包封率为45.6%。体外释放实验表明纳米微粒具有缓释特性,在模拟体液中,10天的累积释药达94.27%。结论:以聚乳酸纳米微粒作为5鄄FU载体,可改变5鄄FU在体内的药代动力学行为,具有缓释作用,可制备为静脉用药,延长药物在体内的循环时间,发挥更好的抗肿瘤效应。     

MAGE-3多肽纳米疫苗对小鼠胃癌种植瘤抑瘤效应研究

背景与目的:纳米颗粒作为疫苗载体可保护抗原免受酶解,增强免疫原性,是一类极具开发潜力的新型疫苗载体。本实验制备负载CD4+CD8+T细胞表位MAGE-3多肽抗原的纳米疫苗,探讨其相关特性及抗肿瘤免疫。方法:利用自组装技术制备多肽/Chit-DC(壳聚糖-脱氧胆酸)载药纳米胶束,透射电镜观察纳米微观形态,荧光分光光度法计算负载率、载药量,并测定药物释放规律。流式细胞仪检测DC(树突状细胞)对药物的吞噬率,酶联免疫斑点实验(ELISPOT)和细胞毒性实验检测MAGE-3多肽纳米疫苗激活机体细胞免疫反应的状况。动物实验观察其体内抑瘤效应。结果:成功制备多肽/Chit-DC纳米胶束,药物包封率约为37%,载药量为17%。载药纳米颗粒中的多肽在pH7.4的PBS中释放缓慢,于48h达释放平台;在2mg/mL溶菌酶溶液中,药物有一定的突释现象,于24h达释放平台。ELISPOT和细胞毒性实验显示MAGE-3多肽纳米疫苗可以激活体内免疫反应而产生针对MAGE-3的CTL,特异性杀伤表达MAGE-3的肿瘤细胞。体内抑瘤实验显示,多肽纳米疫苗组相对肿瘤抑制率为37.81%。结论:MAGE-3多肽/Chit-DC纳米疫苗能有效激活体内的抗肿瘤免疫效应,抑制MFC小鼠前胃癌细胞的生长。     

乳糖酸修饰的介孔二氧化硅纳米粒子靶向肝癌研究

目的:合成一种具有肝癌特异性的纳米药物载体,实现对肝癌细胞靶向释放化疗药物阿霉素（doxorubicin,DOX）。方法:本研究将具有肝癌特异性的配体乳糖酸（lactobionic acid,LA）修饰到介孔二氧化硅（mesoporous silica nanoparticles,MSN）表面,合成具有肝癌靶向作用的纳米载体LA-MSN,然后用LA-MSN负载化疗药物阿霉素,形成具有肝癌特异性靶向杀伤作用的纳米药物DOX/LA-MSN。结果:细胞荧光成像以及细胞电子显微镜实验显示乳糖酸具有良好的肝癌细胞靶向作用并能有效转运DOX/LA-MSN纳米药物进入肝癌细胞。 体外杀伤实验显示DOX/LA-MSN纳米药物在体外能够有效杀伤HepG2肝癌细胞,小动物活体成像实验表明LA-MSN纳米药物具有在体内靶向实体肝癌的能力。结论:DOX/LA-MSN纳米药物能够有效避免阿霉素药物非特异性的缺点,实现对肝癌靶向治疗,是一种具有良好应用前景的纳米药物载体。     

磷酸钙/磷脂-MPEG组装复合纳米粒促进耐药细胞MCF-7/MIT的药物摄取研究

背景与目的:乳腺癌耐药是导致临床上化疗失败的一个重要原因,逆转乳腺癌耐药已经成为急待解决的问题.纳米递送系统作为药物载体有很多优点,将其作为抗癌药物载体是逆转肿瘤耐药的有效策略之一.本文研究一种新型的纳米递送系统:磷酸钙/磷脂-MPEG组装复合纳米粒对乳腺癌耐药相关蛋白(breast cancer resistance protein,BCRP)高表达的乳腺癌盐酸米托蒽醌(mitoxantrone,MIT)耐药细胞MCF-7/MIT药物摄取的影响,从而探讨该纳米递送系统对MCF-7/MIT细胞耐药性的逆转作用.方法:设计并制备了磷酸钙/磷脂组装复合纳米粒,考察了载盐酸米托葸醌纳米粒的包封率和体外药物释放规律,定量比较了MCF-7和MCF-7/MIT细胞对载药纳米粒和游离药物的摄取,并采用激光共聚焦显微镜观察方法比较细胞摄取载药纳米粒和游离药物后药物在细胞内分布情况.结果:磷酸钙/磷脂组装复合纳米粒呈均匀的多孔球形,粒径＜100 nm,包载药物盐酸米托蒽醌的包封率为(89.45±0.05)%,药物释放呈初期突释和后期缓释两相.载药纳米粒与游离药物作用于细胞1 h后,在MCF-7/MIT细胞内的药物摄取量前者是后者的1.89倍,在MCF-7细胞内的药物摄取量前者是后者的2.33倍,载药纳米粒可以携带药物进入细胞核,而游离药物未见明显的核内分布.结论:磷酸钙/磷脂-MPEG组装复合纳米粒可以促进乳腺癌细胞MCF-7和MCF-7/MIT细胞对抗癌药物盐酸米托蒽醌的摄取,并能携带药物进入细胞核,是一种有潜力的逆转肿瘤耐药纳米药物载体.     

载5-FU免疫纳米微粒的体外释药及其抗癌效应研究

目的：研究生物可降解抗癌药载5-FU免疫纳米微粒的释药特点，鉴定其体外杀伤肿瘤细胞的活性、方法：采用恒温振荡透析法和一阶导数紫外分光光度法测定了载5-FU免疫纳米微粒的药物释放特性；MTT法测定了不同时相载5-Fu免疫纳米微粒对5种肿瘤细胞株的杀伤活性结果：载5-FU免疫纳米微粒具有良好的缓释功能，半量释放期t1/2为10．4天，载5-FU免疫纳米微粒对5种肿瘤细胞株均有较强的杀伤活性，且杀伤活性与作用时间和释药量呈正相关关系，结论：载5-FU免疫纳米微粒中药物分布均匀；载5-FU免疫纳米微粒制备和溶蚀过程对5Fu的药效无影响载5-FU免疫纳米微粒具有良好的缓释功能能在较长时间内维持有效的杀伤活性。     

多巴胺包裹的载药纳米金粒子在骨肉瘤光热治疗和化疗协同治疗中应用的实验研究

目的:探究负载化疗药物阿霉素（doxorubicin,DOX）的聚多巴胺包裹纳米金粒子用于化疗与光热协同治疗在骨肉瘤中的应用效果。方法:分别合成纳米金粒子（Au）、聚多巴胺包裹的纳米金粒子（Au@PDA）及载药后的纳米粒子（Au@PDA@DOX）。利用高倍透射电镜表征其形貌;利用动态光散射仪检测其粒径;利用近红外热成像仪表征其光热转换效能;考察药物的载药率及体外释放情况。体外的抗肿瘤实验中,将骨肉瘤MG-63细胞分为5组:PBS对照组、游离DOX组、Au@PDA+激光组、Au@PDA@DOX组和Au@PDA@DOX+激光组。采用CCK-8法及活死细胞染色检测各实验组对骨肉瘤MG-63细胞的杀伤效果,使用电感耦合等离子体质谱（ICP-MS）去检测骨肉瘤对Au@PDA@DOX和Au@PDA的摄取情况,使用荧光倒置显微镜观察各组细胞凋亡情况。结果:成功制备出粒径为（13.3±0.8）nm的纳米金粒子,使用聚多巴胺包裹的纳米金粒子粒径为（185.6±6.0）nm,负载DOX后粒径增大到了（288.0±6.2）nm,载药量为（12.8±0.8）%,在酸性条件下,DOX的释放速度加快;细胞吞噬实验表明MG-63细胞对Au@PDA@DOX纳米粒子的吞噬量高于Au@PDA纳米粒子;单一治疗及光热治疗与化疗协同杀伤MG-63细胞的能力评估结果表明,联合作用的效果大于单一治疗。结论:负载DOX的Au@PDA纳米系统表现出良好的光热效应,能够抑制MG-63细胞的生长。该纳米系统实现了化疗与光热协同作用,可用于骨肉瘤的治疗。     

磁性阿霉素纳米药物研制及其靶向性的实验研究

目的制备磁性阿霉素聚氰基丙烯酸正丁酯纳米粒（ADM-PBCA-MNPS），观察其在正常小鼠体内的靶向分布，为肿瘤的靶向治疗提供一种可能具有临床应用前景的新药。方法采用乳化聚合法制备ADM-PBCA-MNPS。24只昆明小鼠随机分为4组，作相应处理后，尾静脉注射不同药物，观察小鼠体内的靶向分布差异。结果本实验制得了稳定的纳米胶体溶液，平均粒径13．13nm，包封率90．73％，载药量10．68％。ADM-PBCA-MNPS在体外具有良好的磁场响应性，饱和磁化强度为0．558emu／g，且在磁场作用下体内靶向性显著，靶器官靶向指数是非靶器官的3．9倍。结论成功制备ADM-PBCA-MNPS，制备的纳米粒在正常小鼠体内呈靶向聚集分布。     

负载奥沙利铂纳米粒子的制备及抗肿瘤效果研究

目的:采用聚乙二醇-聚乳酸羟基乙酸(mPEG-PLGA)二亲嵌段共聚物为载体,制备负载奥沙利铂的纳米粒子(nanoparticle,NP),全面考察其性质及体内抗肿瘤效果.方法:通过双乳化挥发法,制备奥沙利铂载药纳米粒子,考察纳米粒子的形态、粒径分布、稳定性、体外释放特性及体内抗肿瘤效果等性质.结果:所制得奥沙利铂纳米粒子为较规则的圆球形,平均粒径200.6-242.1 nm,稳定性实验提示其稳定性良好;平均包封率和载药量分别为(65.62±1.27)％和(3.21±0.02)％,体外释放曲线显示了奥沙利铂纳米粒子良好的缓释特性.体内实验中,相比对照组和空白组,纳米粒子组能明显抑制肿瘤的生长,相对裸药组能明显降低药物的毒副反应,且能够延长小鼠的平均生存期.结论:实验结果为肿瘤“带瘤生存”的治疗理念提供了新的思路和科学依据.     

透明质酸修饰的pH响应型阿霉素纳米递送系统靶向多发性骨髓瘤的体外研究

目的:构建一种特异性靶向多发性骨髓瘤的pH响应型纳米递送系统,实现对多发性骨髓瘤细胞靶向释放化疗药物阿霉素。方法:采用酸敏感的DSPE-PEOz和阳离子类脂DOTAP包封模型药物阿霉素（doxorubicin,DOX）,得到阿霉素纳米递送系统（DOX-NDS）,并经HA-PEG2000-DSPE（HA）靶向长循环修饰,最终制得阿霉素靶向纳米递送系统（DOX-HA-NDS）;纳米粒度电位仪分析DOX-HA-NDS的粒径和Zeta电位;多功能酶标仪检测DOX-HA-NDS的包封率（encapsulation efficiency,EE）和载药量（drug loading,DL）;透析法研究DOX-HA-NDS在pH 5.0和pH 7.4条件下的体外释药行为;流式细胞仪检测其细胞摄入;CCK-8法评价空白靶向纳米递送系统（Blank-HA-NDS）的毒性和DOX-HA-NDS的细胞增殖抑制作用。结果:构建的DOX-HA-NDS粒径为（193.1±5.0）nm,Zeta电位为（-41.1±2.0）mV,离心法和透析法测得包封率分别高达93%和90%,载药量为32.76%和32%,4 ℃存储能稳定6个月以上。在pH 7.4条件下,DOX-HA-NDS的释药缓慢,且6 h累积释放率仅为30%,而在pH 5.0条件下,DOX-HA-NDS的释药明显加快,6 h累积释放率高达97%,表明构建的阿霉素靶向纳米递送系统具有pH响应控释性能。细胞摄入实验结果表明,经HA修饰后的阿霉素纳米递送系统可以更有效靶向肿瘤细胞;体外抗肿瘤活性结果表明,Blank-HA-NDS基本无细胞毒性,DOX-HA-NDS对人多发性骨髓瘤细胞（ARH-77）的增殖抑制作用最强。结论:构建的阿霉素靶向纳米递送系统不仅包封率高,而且兼具主动靶向和pH响应控释性能,提高对DOX的输送效率,从而增强了其对ARH-77的细胞增殖抑制作用。     

Nuclear delivery of doxorubicin via folate-targeted liposomes with bypass of multidrug-resistance efflux pump.

Folic acid, attached to polyethyleneglycol-derivatized, distearoyl-phosphatidylethanolamine, was used to target in vitro liposomes to folate receptor (FR)-overexpressing tumor cells. Confocal fluorescence microscopic observations demonstrated binding and subsequent internalization of rhodamine-labeled liposomes by a high FR-expressing, murine lung carcinoma line (M109-HiFR cells), with inhibition by free folic acid. Additional experiments tracking doxorubicin (DOX) fluorescence with DOX-loaded, folate-targeted liposomes (FTLs) indicate that liposomal DOX is rapidly internalized, released in the cytoplasmic compartment, and, shortly thereafter, detected in the nucleus, the entire process lasting 1-2 h. FR-mediated cell uptake of targeted liposomal DOX into a multidrug-resistant subline of M109-HiFR cells (M109R-HiFR) was unaffected by P-glycoprotein-mediated drug efflux, in sharp contrast to uptake of free DOX, based on verapamil-blockade experiments with quantitation of cell-associated DOX and flow cytometry analysis. Delivery of DOX by FTLs to M109R-HiFR cells increased continuously with time of exposure, reaching higher drug concentrations in whole cells and nuclei compared with exposure to free DOX. The in vitro cytotoxic activity obtained with DOX-loaded FTLs was 10-fold greater than that of the nontargeted liposome formulation, but was not improved over that of free DOX despite the higher cellular drug levels obtained with the targeted liposomes in M109R-HiFR cells. However, if M109R-HiFR cells were exposed to drugs in vitro and tested in an in vivo adoptive assay for tumor growth in syngeneic mice along a 5-week time span, FTL DOX was significantly more tumor inhibitory than free DOX. It is suggested that the biological activity of liposomal DOX released inside the cellular compartment is reduced in vitro due to the aggregated state of DOX, resulting from the liposome drug-loading process, and requires a long period of time and/or an in vivo environment for full expression.     

Folate-mediated mitochondrial targeting with doxorubicin-polyrotaxane nanoparticles overcomes multidrug resistance

Resistance to treatment with anticancer drugs is a significant obstacle and a fundamental cause of therapeutic failure in cancer therapy. Functional doxorubicin (DOX) nanoparticles for targeted delivery of the classical cytotoxic anticancer drug DOX to tumor cells, using folate-terminated polyrotaxanes along with dequalinium, have been developed and proven to overcome this resistance due to specific molecular features, including a size of approximately 101 nm, a zeta potential of 3.25 mV and drug-loading content of 18%. Compared with free DOX, DOX hydrochloride, DOX nanoparticles, and targeted DOX nanoparticles, the functional DOX nanoparticles exhibited the strongest anticancer efficacy in vitro and in the drug-resistant MCF-7/ Adr (DOX) xenograft tumor model. More specifically, the nanoparticles significantly increased the intracellular uptake of DOX, selectively accumulating in mitochondria and the endoplasmic reticulum after treatment, with release of cytochrome C as a result. Furthermore, the caspase-9 and caspase-3 cascade was activated by the functional DOX nanoparticles through upregulation of the pro-apoptotic proteins Bax and Bid and suppression of the antiapoptotic protein Bcl-2, thereby enhancing apoptosis by acting on the mitochondrial signaling pathways. In conclusion, functional DOX nanoparticles may provide a strategy for increasing the solubility of DOX and overcoming multidrug-resistant cancers.     

Combination of ultrasound and bubble liposome enhance the effect of doxorubicin and inhibit murine osteosarcoma growth

If ultrasound (US) is applied to cells, permeability across the cell membrane temporarily increases, making it easier for drugs to be taken into the cells from around the cell membrane. Moreover, when used in combination with Bubble liposome (BL: liposomes which entrap an ultrasound imaging gas), even low-power ultrasound can facilitate drug delivery into cells. In the present study, we constructed a new drug delivery system (DDS) involving concomitant use of US and BL with doxorubicin (DOX), a key drug in the chemotherapy of osteosarcoma, and demonstrated both in vitro and in vivo that it markedly inhibited the proliferation of osteosarcoma cells. Furthermore, this system achieved an equivalent antitumor effect at about 1/5 the dose of antitumor agent employed in monotherapy with DOX. These findings suggest the possibility of reduction of adverse events. In this experiment, US and liposomes were tested, both of which are already in use in clinical practice. US and liposomes are both very safe in the body. The DDS composed of these elements we designed can be applied in simple and site-specific fashion and is therefore promising as a new, clinically feasible method of treatment.     

Characterization and anti-tumor activity of chemical conjugation of doxorubicin in polymeric micelles (DOX-P) in vitro

Characterization and anti-tumor activity of chemical conjugation of doxorubicin (DOX) in polymeric micelles were investigated. Polymeric micelles with chemical conjugation of doxorubicin (DOX-P) were prepared. Succinic anhydride activated pluronic F68 was first synthesized and the primary amine group in doxorubicin was conjugated to the terminal carboxyl of pluronic F68 via a amide. The resulting polymeric micelles in aqueous solution were characterized by measurement of size, ξ-potential, drug loading and critical micelle concentration. From characterization results, DOX-P micelles had superiorities over physically-loaded DOX micelles in loading efficiency, diameter and CMC value. From drug release experiment in vitro, DOX-P micelles reached a sustained release profile for DOX. The cytotoxic activity of the micelles against A549/DOX cells was greater than free DOX. Fluorescence microscope observation and flow cytometry analysis supported the enhanced cellular uptake of the micelles. From A549/DOX cells experiments, DOX-P micelles could enhance DOX anti-tumor activity and circumvent the multi-drug resistance (MDR) of A549/DOX cells. With low CMC value, high loading efficiency, nanometer diameter, good penetration ability and controlled release behaviour, DOX-P micelles might be developed as a new cancer targeted delivery system.     

Mechanisms of the in vivo resistance to adriamycin and modulation by calcium channel blockers in mice

A sensitive fluorometric assay using Hoechst 33258 and a modified alkaline elution procedure were used to quantitate DNA single-strand breaks following an in vivo drug treatment of mice bearing P-388/S and P-388/R cells. After an i.p. treatment of mice with 1 to 20 mg/kg Adriamycin (DOX), the following differences between sensitive and resistant P-388 cells were observed: (a) at 2 h following drug treatment the net intracellular accumulation of Adriamycin in sensitive cells was 2- to 3-fold higher than resistant cells at all doses tested; (b) utilizing a therapeutic dose of DOX (10 mg/kg), the amount of single-strand breaks of DNA in sensitive and resistant cells was significantly different, K x 10(2) = 13.6 +/- 1.1 (SD) versus 3.6 +/- 0.9, respectively; (c) the 10 and 50% lethal doses for verapamil (VEP) were 10 and 23 mg/kg and for a tiapamil analogue, N-(3,4-dimethoxyphenethyl)-N-methyl-2-(2-naphthyl)-m-dithiane-2-propylam ine hydrochloride (DMDP), were 107 and 126 mg/kg, respectively; (d) while the in vivo intracellular accumulation and retention of DOX in sensitive cells were not affected by DMDP or VEP treatment, complete restoration of DOX accumulation and retention was achieved in resistant cells treated with well-tolerated doses of DMDP of 30 and 60 mg/kg. In contrast, utilizing the optimally tolerated dose of VEP (5 mg/kg), only partial restoration of DOX accumulation and retention in resistant cells was achieved; (e) DMDP or VEP did not alter the high level of DNA single-strand breaks induced by DOX in sensitive cells; in resistant cells, however, an increase in single-strand breaks of DNA was observed following treatment with DOX in combination with DMDP and to a lesser extent with VEP; and (f) the rapid DNA repair in resistant cells was inhibited by DMDP but not by VEP. These data demonstrate that DMDP but not VEP can effectively restore the in vivo intracellular accumulation of DOX in resistant cells at achievable nontoxic plasma concentrations. Previous studies have demonstrated that the in vitro intracellular concentrations and retention of DOX by resistant cells can be restored by VEP. The results reported herein demonstrated that similar effects can be achieved, however, in vivo by using a new calcium channel blocker, DMDP, with less in vivo toxicity and more efficacy than VEP in restoring cellular drug concentration, retention, and repair of DNA damage in the resistant cells.     

Inhibition of C6 glioma in vivo by combination chemotherapy of implantation of polymer wafer and intracarotid perfusion of transferrin-decorated nanoparticles

The objective of this study was to develop a combination chemotherapy of implantation of a 3-bis(2-chloroethyl)-1-nitrosourea (BCNU)-loaded wafer and intracarotid perfusion of BCNU-loaded nanoparticles for glioma treatment in?vivo. BCNU-loaded poly(D,L-lactic acid) (PLA) nanoparticles coated with transferrin (Tf) were prepared by a solvent evaporation/diffusion method using Tf as the emulsifier. X-ray photoelectron spectroscopy, Bratton-Marshall colorimetric assay and zeta-potential analysis confirmed the existence of Tf on the nanoparticles and their functional activities. BCNU-loaded PLA wafers were made of BCNU-loaded PLA microspheres. In?vitro drug release behavior demonstrated that BCNU was released from the Tf-PLA nanoparticles and wafers in two distinct phases. The biodistribution of Tf-coated nanoparticles investigated by 99mTc-labeled single-photon emission computed tomography (SPECT) showed that the surface-containing Tf-PLA nanoparticles were concentrated in the brain. Inhibition of tumor growth in the C6 glioma-bearing animal model showed that combinational chemotherapy of BCNU-loaded wafer and BCNU-loaded PLA nanoparticles had a stronger inhibitory effect and prolonged the average survival time of rats (164%) compared with that of the control group. Furthermore, the tumors of this treatment group were not visible by examination at 4 weeks. The results of this study demonstrate for the first time that combination therapy of implantation of a BCNU-loaded wafer and intracarotid perfusion of BCNU-loaded nanoparticles may be a new strategy for glioma gene therapy.     

The influence of glucocorticoids on the growth of a human leiomyosarcoma cell line SK-LMS-1

A cell line derived from a human leiomyosarcoma, SK-LMS-I, has cystolic [Bmax 201.6 +/- 39.7, means +/- SD, fm/mg cytosol protein KD 14.6 +/- 7.8 nM (n = 8)] and nuclear [Bmax 189.2 +/- 87.3 fM/mg DNA, KD 4.8 +/- 0.26 nM (n = 5)] glucocorticoid receptor, by Scatchard analysis of tumors grown in male athymic mice. Tumor growth of SK-LMS-I cells in male athymic mice is inhibited by daily s.c. injection of DEX 5 micrograms, DEX 25 micrograms, DEX 5 micrograms with 5 mu RU-486 and 5 micrograms RU-486. In sharp contrast, in vitro, glucocorticoid markedly stimulates the growth (as determined by cell number) of SK-LMS-I cells, principally at higher cell densities (days 10-21 of growth carried on over a 21- to 23-day period), the greatest stimulation being seen with DEX 10(-6) to 10(-8) M, and no stimulation being seen with DEX 10(-9) and 10(-10) M. In vitro, glucocorticoids with higher affinity for the GR stimulate growth, steroids with lower affinity inhibit growth. No alterations in cell-cycle distribution (percent G0/G1, S, or G2/m) could be found by flow cytometric analysis of glucocorticoid-stimulated asynchronously growing cultures. Single, isolated, untreated SK-LMS-I cells form colonies in soft agar with an efficiency of 1.78 +/- 0.10%. Pre-treatment of cells with DEX 10(-7) M increases this to 3.24 +/- 0.17%, while cells pre-treated with both DEX 10(-7) M RU-486 10(7) M form colonies with the same efficiency as untreated cells. Glucocorticoids have inhibitory effects on in vivo growth and stimulatory effects on in vitro growth of a GR-positive human leiomyosarcoma cell line.     

In vitro and in vivo antitumor effects of doxorubicin loaded with bacterial magnetosomes (DBMs) on H22 cells: the magnetic bio-nanoparticles as drug carriers

Hepatocellular carcinoma (HCC) is the most common form of cancer although effective therapeutic strategy especially targeted therapy is lacking. We recently employed bacterial magnetosomes (BMs) as the magnetic-targeted drug carrier and found an antitumor effect of doxorubicin (DOX)-loaded BMs (DBMs) in EMT-6 and HL60 cell lines. The aim of this study was to evaluate the in vitro and in vivo anti-neoplastic effects of DBMs on hepatic cancer. DBMs, DOX and BMs displayed tumor suppression rates of 86.8%, 78.6% and 4.3%, respectively, in H22 cell-bearing mice. The mortality rates following administration of DBMs, DOX and BMs were 20%, 80% and 0%, respectively. Pathological examination of hearts and tumors revealed that both DBMs and DOX effectively inhibited tumor growth although DBMs displayed a much lower cardiac toxicity compared with DOX. The DBMs were cytotoxic to H22 cells manifested as inhibition of cell proliferation and c-myc expression, consistent with DOX. The IC(50) of DOX, DBMs and BMs in target cells were 5.309 +/- 0.010, 4.652 +/- 0.256 and 22.106 +/- 3.330 microg/ml, respectively. Our data revealed both in vitro and in vivo antitumor property of DBMs similar to that of DOX. More importantly, the adverse cardiac toxicity was significantly reduced in DBMs compared with DOX. Collectively, our study suggests the therapeutic potential of DBMs in target-therapy against liver cancer.