载奥沙利铂的还原敏感型四氧化三铁纳米粒的体内外靶向性评价

化疗药物的非特异性蓄积和释放是影响其治疗效果以及引起不良反应的主要原因。现阶段,将药物纳米制剂化并且进行响应性释药设计是提高药物肿瘤特异性蓄积量和降低其不良反应的重要策略。本研究首先合成了一种α-烯醇化酶靶向肽修饰的共价荷载奥沙利铂前药的聚乙二醇聚赖氨酸嵌段共聚物,通过相转透析法制备了载药聚合物包覆的四氧化三铁纳米粒,以提高奥沙利铂的循环稳定性及肿瘤靶向性。在体外和活体水平对靶向修饰的载药四氧化三铁纳米粒的物理化学性质、还原响应药物释放、细胞摄取和肿瘤靶向等生物学功能进行了相关研究。体外的还原响应释药、肿瘤靶向摄取及摄取抑制考察结果显示,在模拟肿瘤细胞浆微环境的还原条件中,载药纳米粒可实现3 h内超80%的奥沙利铂原型药物的快速释放;流式细胞术的结果显示,靶向多肽的修饰能够增加肿瘤细胞对载药纳米粒的摄取量,并且靶向载药纳米粒主要是通过受体蛋白和小窝蛋白介导的能量依赖的内吞途径被肿瘤细胞所摄取的。所有动物实验操作均通过复旦大学药学院实验动物伦理委员会批准并遵循相关管理规定。药物动力学实验结果显示,纳米制剂化能显著增加奥沙利铂的平均药时曲线下面积(AUC_0-∞),约为...     

胞内酶敏感肿瘤靶向递药体系的合成及应用

目的利用对乳腺癌肿瘤细胞MDA-MB-435内特有酶豆蛋白酶(legumain)敏感的多肽(AANL)连接阿霉素(DOX)构建具有胞内特异性释药功能的纳米递药系统,并对AANL在含有legumain环境下的断裂效率进行研究。方法将DOX用AANL修饰得到AANL-DOX(AD),再将AD连接至4-arm PEG上,最后将细胞穿膜肽(TAT)连接至4-arm PEG-AD上,制备出TAT-PEG-AD并自组装形成纳米粒(TPAD)。核磁表征TAT-PEG-AANL-DOX;粒度分析仪和透射电镜测定纳米粒的粒径及外观形貌;模拟体内、肿瘤微环境和胞内环境通过动态透析法研究legumain对AANL的断裂效率并模拟DOX的药物控释效率;细胞毒性研究TPAD对MDA-MB-435细胞的毒性作用。结果核磁共振氢谱证实TAT-PEG-AANL-DOX合成成功;测定TPAD的粒径为126.3 nm;透射电镜(TEM)观察纳米粒结构圆整,粒径为80 nm;24 h的累积释药量为82.2%;体外细胞毒性研究表明,TPAD对MDA-MB-435细胞有较好的杀伤作用,其效果接近游离DOX的细胞毒性。结论利用legumain敏感多肽连接DOX制备具有胞内特异性释药功能的纳米粒,能够有效实现肿瘤细胞内晚期内涵体和溶酶体精准释药,提高抗肿瘤药物的生物利用度,值得进一步研究。     

氧化还原敏感型靶向纳米给药系统的研究进展

理想的肿瘤靶向给药系统应在肿瘤部位高度累积且快速释放药物,而在血液循环中无泄漏,利用肿瘤环境改变的氧化还原状态及细胞内外的谷胱甘肽差异,结合纳米给药系统,可实现精准肿瘤靶向.本文对氧化还原敏感型靶向纳米给药系统的原理、氧化还原敏感键及其构建方法进行了介绍,并对基于脂质体、纳米粒、纳米胶束、纳米凝胶4种载体的不同氧化还原...     

pH响应性地塞米松前药纳米粒的相关研究

目的 制备一种具有pH响应性的地塞米松前药纳米粒给药系统.方法 通过席夫碱反应,将地塞米松与低分子量的支化聚乙烯亚胺相连,得到DXM-PEI(DP)前药,对前药的结构与载药量进行定性与定量分析.采用交联法将前药制备成纳米粒,并研究纳米粒的粒径、PDI、Zeta电位等理化性质及生物相容性.结果 交联法制得DP前药纳米粒的...     

凝集素修饰的纳米粒给药系统研究进展

通过检索和总结国内外相关文献,阐述了近年来凝集素修饰的纳米粒给药系统的研究进展,包括凝集素对黏膜及癌细胞特异作用机制,对纳米粒修饰的研究现状和应用,及对纳米粒的键合方法,展望了凝集素修饰的纳米粒在黏膜给药系统中的应用前景,旨在为靶向给药研究提供新思路。     

阿霉素纳米粒对MRP介导的膀胱肿瘤多药耐药细胞株EJ/MRP多药耐药性的逆转作用

目的 研究阿霉素纳米粒对多药耐药相关蛋白(MRP)介导的膀胱肿瘤多药耐药的逆转作用.方法 采用四甲基偶氮唑盐(MTT)法测定药物的体外杀伤作用,应用流式细胞术测定细胞内药物浓度.结果 阿霉素纳米粒对EJ细胞的细胞毒作用与阿霉素相似,EJ/MRP 细胞对阿霉素纳米粒较阿霉素敏感4.00倍.结论 阿霉素纳米粒通过增加耐药细胞内阿霉素浓度而有效逆转多药耐药.     

神经病理性疼痛互联体前药的设计和合成（II）*

目的：合成具有抗神经病理性疼痛的加巴喷丁、普瑞巴林、美金刚胺以及万拉法新的新互联体前药化合物。方法：四种药物通过酯化、酰胺反应由不同的连接子合成酰胺类和混合键类互联体前药。结果：共合成8个新的互联体前药化合物。结论：具有活泼基团的小分子药物能够通过体内容易酶解的化学键（酯键、酰胺键）合成相对分子质量适中的互联体前药。     

神经病理性疼痛互联体前药的设计和合成(Ⅰ)

目的:合成具有抗神经病理性疼痛的加巴喷丁和普瑞巴林的互联体前药化合物.方法:通过酯化、酰胺反应由不同的二醇或二酸连接加巴喷丁和普瑞巴林合成二酯、酰胺、拟肽类等化合物.结果:共合成26个新的互联体前药化合物.结论:具有活泼基团的小分子药物能够通过体内容易酶解的化学键(酯键、酰胺键)合成分子量适中的互联体前药.     

杯状细胞靶向壳聚糖纳米粒的制备及吸收

目的将多肽CSKSSDYQC(CSK)化学结合到三甲基壳聚糖(trimethyl chitosan chloride,TMC)上,构建杯状细胞靶向口服给药系统,以期获得口服生物利用度较高的给药系统。方法通过化学合成的方法将CSK连接到TMC上,并用异硫氰酸荧光素(fluorescein isothiocyanate,FITC)进行荧光标记。以粒径和成球率为指标,采用单因素实验得到纳米粒的制备处方。用乳酸脱氢酶细胞毒性测试(lactate dehydrogenase,LDH)法分别考察载体材料和纳米粒对Caco-2和HT29-MTX细胞存活率的影响。建立Caco-2/HT29-MTX共培养细胞单分子层,进行纳米粒的跨膜转运实验。利用免疫荧光法考察纳米粒在体内吸收情况。结果按照最优处方制得的FITC-TMC纳米粒和FITC-TMC-CSK纳米粒的粒径分别为214.5 nm和234.3 nm;电位分别为15.81 mV和8.96 mV;成球率分别为98.14%和91.58%。FITC-TMC-CSK的细胞毒性低于FITC-TMC,纳米粒的细胞毒性低于载体材料。FITC-TMC-CSK纳米粒的累积透过量高于FITC-TMC纳米粒,其表观渗透系数(P_(app))值是后者的2.17倍。FITC-TMC-CSK纳米粒在正常大鼠不同肠段吸收顺序为回肠>空肠>十二指肠。结论将CSK键合到TMC上构建杯状细胞靶向纳米粒,能有效提高纳米粒的吸收,在药物口服吸收的研究中具有广阔的应用前景。     

Folate-targeted enzyme prodrug cancer therapy utilizing penicillin-V amidase and a doxorubicin prodrug

In antibody-targeted enzyme prodrug therapy, a monoclonal antibody (mAb) covalently linked to an enzyme is commonly exploited to concentrate the enzyme on the tumor cell surface prior to administration of a relatively nontoxic prodrug. The tumor-localized enzyme then converts the prodrug into a cytotoxic agent, which in turn diffuses into the tumor causing localized cell death. In this paper, we have substituted folic acid for the mAb as a mean of delivering an attached enzyme, penicillin-V amidase (PVA), to folate receptor (FR)-positive tumor cells. The enzyme PVA is capable of converting a doxorubicin-N-p-hydroxyphenoxyacetamide prodrug (DPO) into its potent parent drug, doxorubicin. For PVA targeting, each PVA molecule was covalently labeled with three molecules of folic acid via the formation of amide bonds. In vitro binding assays showed that folate-PVA-125I conjugates bind specifically to KB cells (FR-positive tumor cells) but not to A549 cells (FR-negative tumor cells). Moreover, in a series of in vitro cytotoxicity tests, folate-PVA conjugates were found to kill folate receptor positive but not receptor negative cells, and when bound to FR-positive cells, folate-PVA conjugates rendered the DPO prodrug as toxic as free doxorubicin (IC50, approximately 0.6 microM). Finally, preliminary in vivo plasma clearance studies in normal mice revealed that i.v. administered folate-PVA-125I and PVA-125I are both cleared from the blood within a 24 h time period, removing concern that nonspecifically trapped folate-PVA might activate prodrug in nontargeted tissues. In view of the fact that only a small number of folate-PVA molecules are required to mediate killing of target cells in vitro, these data argue that folate-targeted enzyme prodrug therapy should be considered for tumor eradication in vivo.     

Dual-responsive nanoparticles with transformable shape and reversible charge for amplified chemo-photodynamic therapy of breast cancer

Herein, we designed a dual-response shape transformation and charge reversal strategy with chemo-photodynamic therapy to improve the blood circulation time, tumor penetration and retention, which finally enhanced the anti-tumor effect. In the system, hydrophobic photosensitizer chlorin e6 (Ce6), hydrophilic chemotherapeutic drug berberrubine (BBR) and matrix metalloproteinase-2 (MMP-2) response peptide (PLGVRKLVFF) were coupled by linkers to form a linear triblock molecule BBR-PLGVRKLVFF-Ce6 (BPC), which can self-assemble into nanoparticles. Then, positively charged BPC and polyethylene glycol-histidine (PEG-His) were mixed to form PEG-His@BPC with negative surface charge and long blood circulation time. Due to the acidic tumor microenvironment, the PEG shell was detached from PEG-His@BPC attributing to protonation of the histidine, which achieved charge reversal, size reduction and enhanced tumor penetration. At the same time, enzyme cutting site was exposed, and the spherical nanoparticles could transform into nanofibers following the enzymolysis by MMP-2, while BBR was released to kill tumors by inducing apoptosis. Compared with original nanoparticles, the nanofibers with photosensitizer Ce6 retained within tumor site for a longer time. Collectively, we provided a good example to fully use the intrinsic properties of different drugs and linkers to construct tumor microenvironment-responsive charge reversal and shape transformable nanoparticles with synergistic antitumor effect.     

Small changes in the length of diselenide bond-containing linkages exert great influences on the antitumor activity of docetaxel homodimeric prodrug nanoassemblies

Homodimeric prodrug-based self-assembled nanoparticles, with carrier-free structure and ultrahigh drug loading, is drawing more and more attentions. Homodimeric prodrugs are composed of two drug molecules and a pivotal linkage. The influence of the linkages on the self-assembly, in vivo fate and antitumor activity of homodimeric prodrugs is the focus of research. Herein, three docetaxel (DTX) homodimeric prodrugs are developed using different lengths of diselenide bond-containing linkages. Interestingly, compared with the other two linkages, the longest diselenide bond-containing linkage could facilitate the self-delivery of DTX prodrugs, thus improving the stability, circulation time and tumor targeting of prodrug nanoassemblies. Besides, the extension of linkages reduces the redox-triggered drug release and cytotoxicity of prodrug nanoassemblies in tumor cells. Although the longest diselenide bond-containing prodrug nanoassemblies possessed the lowest cytotoxicity to 4T1 cells, their stable nanostructure maintained intact during circulation and achieve the maximum accumulation of DTX in tumor cells, which finally “turned the table”. Our study illustrates the crucial role of linkages in homodimeric prodrugs, and gives valuable proposal for the development of advanced nano-DDS for cancer treatment.     

肿瘤代谢重排与肿瘤耐药相关性的研究进展

肿瘤细胞的代谢重编程被认为是肿瘤的十大特征之一。肿瘤组织通过代谢重编程以满足肿瘤快速生长对生物能量、生物合成和氧化还原的需求。伴随着肿瘤代谢重编程,细胞内外的一些代谢产物对基因表达、细胞分化和肿瘤微环境均具有深远的影响。其中最显著的变化包括糖酵解的激活、脂质代谢的增加、线粒体生物合成增强以及磷酸戊糖通路的激活。代谢重编程不仅发生在正常细胞向肿瘤细胞转化的过程中,也发生在晚期肿瘤细胞的发育过程中,与抗癌药物的敏感性有很密切的关系。因此,化疗药物联合细胞代谢抑制剂可能是一种有望克服肿瘤耐药的策略。从这个角度讨论肿瘤细胞代谢与肿瘤耐药的关系,并总结出失调的代谢通路可以作为潜在的肿瘤治疗靶点,来抑制对常规治疗耐药的肿瘤。     

Kinetics of the tissue distributions of sulindac and metabolites. Relevance to sites and rates of bioactivation

Sulindac (sulfoxide) is a prodrug in reversible metabolic equilibrium with its pharmacologically active metabolite, the corresponding sulfide. Following simultaneous parenteral injection of sulfoxide-14C and sulfide-3H at equivalent dosage, all labeled species in the plasma of rats and guinea pigs and in representative tissues were determined at various times. Rate constants for sulfoxide in equilibrium or formed from sulfide, calculated from the rates of interchange of the two labels in plasma, are still higher than those approximated from earlier, single-label studies, and indicate turnovers of total body pools every 45 and 8.5 min in rat and guinea pig, respectively. From the time-course of tissue/plasma ratios of endogenous labeled species, it can be concluded that kidney and liver are major sites of bioactivation of the prodrug, with significant sulfoxide leads to sulfide activity present in all tissues examined. At steady state, tissue concentrations of each redox form are determined by the ratio of the metabolic rate constants for the two opposing biotransformations and by unique tissue/plasma distributive constants for each redox form, resulting in all tissues, except lung, and at all times examined, in a sulfide/sulfoxide ratio greater than one.     

Preparation and characterization of polymeric pH-sensitive STEALTH® nanoparticles for tumor delivery of a lipophilic prodrug of paclitaxel

Paclitaxel is an effective and widely used anti-cancer agent. However, the drug is difficult to formulate for parenteral administration because of its low water solubility and Cremophor EL, the expient used for its formulation, has been shown to cause serious side effects. The present study reports an alternative administration vehicle involving a lipophilic paclitaxel prodrug, paclitaxel oleate, incorporated in the core of a nanoparticle-based dosage form. A hydrophobic poly (β-amino ester) (PbAE) was used to formulate the nanoparticles, which were stabilized with a mixture of phosphatidylcholine, Synperonic? F 108, and poly(ethylene glycol)-dipalmitoyl phosphatidyl ethanolamine. PbAE undergoes rapid dissolution when the pH of the medium is less than 6.5 and is expected to rapidly release its content within the acidic tumor microenvironment and endo/lysosome compartments of cancer cells. PbAE nanoparticles were prepared by an ultrasonication method and characterized for particle size and physical stability. The nanoparticles obtained had a diameter of about 70 nm and a good physical stability when stored at 4 °C. In vitro cellular uptake and release of paclitaxel oleate PbAE nanoparticles were studied in Jurkat acute lymphoblastic leukemia cells. The results were compared with pclitaxel oleate in poly(?-caprolactone) (PCL) particles, that do not display pH-sensitive release behavior, and paclitaxel in PbAE particles. Both uptake and release of the prodrug were faster when administered in PbAE than in PCL, but much slower than those of the free drug in PbAE. Cytotoxicity assay was performed on the formulations at different doses. Paclitaxel and paclitaxel oleate showed almost identical activity, IC50 123 and 128 nM, respectively, while that of the prodrug in PCL was much lower with IC50 at 2.5 μM. Thus, PbAE nanoparticles with the incorporated paclitaxel prodrug paclitaxel oleate may prove useful for replacement of the toxic Cremophor EL and also by improving the distribution of the drug to the tumor.     

Oxidation-strengthened disulfide-bridged prodrug nanoplatforms with cascade facilitated drug release for synergetic photochemotherapy

One of the major barriers in utilizing prodrug nanocarriers for cancer therapy is the slow release of parent drug in tumors. Tumor cells generally display the higher oxidative level than normal cells, and also displayed the heterogeneity in terms of redox homeostasis level. We previously found that the disulfide bond-linkage demonstrates surprising oxidation-sensitivity to form the hydrophilic sulfoxide and sulphone groups. Herein, we develop oxidation-strengthened prodrug nanosystem loaded with pyropheophorbide a (PPa) to achieve light-activatable cascade drug release and enhance therapeutic efficacy. The disulfide bond-driven prodrug nanosystems not only respond to the redox-heterogeneity in tumor, but also respond to the exogenous oxidant (singlet oxygen) elicited by photosensitizers. Once the prodrug nanoparticles (NPs) are activated under irradiation, they would undergo an oxidative self-strengthened process, resulting in a facilitated drug cascade release. The IC₅₀ value of the PPa@PTX-S-S NPs without irradiation was 2-fold higher than those of NPs plus irradiation. In vivo, the PPa@PTX prodrug NPs display prolonged systemic circulation and increased accumulation in tumor site. The PPa@PTX-S-S NPs showed much higher efficiency than free PTX or the PPa@PTX-C-C NPs to suppress the growth of 4T1 tumors. Therefore, this novel oxidation-strengthened disulfide-bridged prodrug-nanosystem has a great potential in the enhanced efficacy of cancer synergetic photochemotherapy.     

Pure redox-sensitive paclitaxel–maleimide prodrug nanoparticles: Endogenous albumin-induced size switching and improved antitumor efficiency

A commercial albumin-bound paclitaxel nano-formulation has been considered a gold standard against breast cancer. However, its application still restricted unfavorable pharmacokinetics and the immunogenicity of exogenous albumin carrier. Herein, we report an albumin-bound tumor redox-responsive paclitaxel prodrugs nano-delivery strategy. Using diverse linkages (thioether bond and disulfide bond), paclitaxel (PTX) was conjugated with an albumin-binding maleimide (MAL) functional group. These pure PTX prodrugs could self-assemble to form uniform and spherical nanoparticles (NPs) in aqueous solution without any excipients. By immediately binding to blood circulating albumin after intravenous administration, NPs are rapidly disintegrated into small prodrug/albumin nanoaggregates in vivo, facilitating PTX prodrugs accumulation in the tumor region via albumin receptor-mediated active targeting. The tumor redox dual-responsive drug release property of prodrugs improves the selectivity of cytotoxicity between normal and cancer cells. Moreover, disulfide bond-containing prodrug/albumin nanoaggregates exhibit long circulation time and superior antitumor efficacy in vivo. This simple and facile strategy integrates the biomimetic characteristic of albumin, tumor redox-responsive on-demand drug release, and provides new opportunities for the development of the high-efficiency antitumor nanomedicines.KEY WORDS: Paclitaxel, Abraxane, Redox-sensitive, Disulfide bond, Maleimide, Prodrug-based nano-drug delivery systems, Prodrug/albumin nanoaggregates, Breast cancer treatment     

Selective activation of anthracycline prodrugs for use in conjunction with ADEPT

A major limitation in the chemotherapy of cancer results from the lack of tumor specificity displayed by most anticancer drugs. In this regard, a great deal of research has been focused on the development of new chemotherapeutic agents that are able to effectively exploit the differences between neoplastic and normal tissues. Several cancerous tissues and tumors are rich in certain lysosomal enzymes as compared with those found in the normal tissues. Thus, a prodrug can be designed to selectively target such tumor cells where it can be activated to antineoplastic agent by tumor-associated antigen-targeted monoclonal antibody-enzyme conjugate (antibody directed enzyme prodrug therapy strategy) or by the action of an enzyme present at high levels in tumor tissues (prodrug monotherapy strategy). This approach protects the normal cells from the cytotoxic effects of the drug. In the last few years, a number of new MAb-based reagents has been clinically approved (Rituxan, Herceptin and Panorex), and several others are now in advanced clinical trials. This review focuses on the design of several different enzyme/prodrug combinations with an emphasis on mechanistic insight and clinical activity.