叶酸靶向双重载药聚合物囊泡制备及其抗肿瘤研究

发布时间：2018-08-03 17:21

【摘要】：癌症是一类对人类健康构成严重威胁的高发、高致死率疾病,化学治疗是非手术治疗癌症的重要方法。近年来,多项临床研究结果表明:单一药物化疗往往已经难以有效控制癌症病情,在治疗的后期还可能出现多药耐药性,而不同抗癌机制化疗药物的联合使用可以达到提高治疗效果、降低药物毒副作用的目的。其中阿霉素与紫杉醇联合用药(即“鸡尾酒疗法”)在临床治疗中已广泛应用。但紫杉醇注射液中使用聚氧乙烯蓖麻油助溶,具有很强的神经毒性和肾脏毒性,盐酸阿霉素在抑制肿瘤增殖的同时也会抑制骨髓的造血能力,并导致严重的心脏毒性和肝脏损伤,而且两种药物游离给药后在体内的代谢途径不同,实际进入肿瘤细胞内的药量难以控制。聚合物囊泡作为药物递送载体,可以将不同溶解性、不同抗癌机制的化疗药物分别载入疏水性膜层内和亲水性内腔中,以提升化疗药物的稳定性,延缓药物代谢,并可凭借囊泡的主动和被动靶向能力,改变药物在生物体内的分布,使药物富集于病变部位,降低全身毒副作用,延缓癌细胞耐药性的产生,起到协同化疗作用。本课题以PEG作为引发物,引发ε-CL开环聚合,聚合成具有良好生物相容性和可生物降解性的聚己内酯-聚乙二醇-聚己内酯(PCL-PEG-PCL,PCEC)两亲性三嵌段共聚物作为载体材料,并以临床广泛使用的化学治疗药物——盐酸阿霉素和紫杉醇作为模型药物,叶酸作为靶向配体,构建叶酸靶向、双重包载药物的聚合物靶向纳米囊泡。在该囊泡中,紫杉醇分布于疏水膜层,盐酸阿霉素包裹于亲水内腔。对所构建的聚合物囊泡进行结构表征、体外细胞实验、动物体内实验等研究,评价其主动靶向和被动靶向能力、体内外抑瘤效果、协同化疗作用以及克服全身毒副作用的效果。透射电镜观察结果显示,两亲性三嵌段共聚物PCL-PEG-PCL中亲水性PEG链段的质量分数约占33%时,能够形成具有较厚膜层和较大空腔结构的聚合物囊泡。细胞摄取研究表明,在叶酸受体过表达的BEL-7404细胞中叶酸靶向修饰的双载药聚合物囊泡(FA-PTX-DOX-PS)内吞效率明显高于无叶酸靶向的双载药聚合物囊泡(PTX-DOX-PS)。体外细胞毒性实验表明,FA-PTX-DOX-PS有效降低游离紫杉醇与阿霉素混合给药的毒性,且相比PTX-DOX-PS能更有效地抑制肿瘤的生长。体内荧光成像实验结果显示,FA-PTX-DOX-PS表现出高效的靶向性,可在肿瘤内累积。此外,体内抗肿瘤研究表明,与临床“鸡尾酒疗法”游离给药相比,所构建的FA-PTX-DOX-PS具有显著的肿瘤靶向性,抑瘤效果更强,同时有效克服临床上“鸡尾酒疗法”产生的全身毒副作用。因此,叶酸靶向双重载药聚合物纳米囊泡是一种具有潜力的可同时递送多种化疗药物用于肿瘤高效、靶向、协同治疗的纳米制剂。
[Abstract]:Cancer is a kind of high incidence of serious threat to human health, high mortality rate, and chemical therapy is an important method for non-surgical treatment of cancer. In recent years, a number of clinical research results show that single drug chemotherapy is often difficult to effectively control the cancer condition, and there may be multidrug resistance in the later period of the treatment, and different anticancer machines. The combined use of chemical and chemotherapeutic drugs can improve the therapeutic effect and reduce the side effects of drug. The combination of doxorubicin and paclitaxel ("cocktail therapy") has been widely used in clinical treatment. However, the use of polyoxyethylene castor oil in Paclitarel Injection has strong neurotoxicity and nephrotoxicity. Acid adriamycin can inhibit the proliferation of tumor and inhibit the hematopoiesis of bone marrow, and lead to severe cardiac toxicity and liver damage, and the metabolic pathways in the body are different after the two drugs are free, and the amount of drugs that actually enter the tumor cells is difficult to control. As a delivery carrier, polymer vesicles can dissolve different solubility The chemotherapeutic drugs of different anticancer mechanisms are loaded into the hydrophobic membrane and the hydrophilic inner cavity respectively to improve the stability of the chemotherapeutic drugs, delay the drug metabolism, and by virtue of the active and passive targeting ability of the vesicles, change the distribution of drugs in the organism, make the drug rich in the lesion, reduce the side effect of the whole body and delay the tolerance of cancer cells. This subject takes PEG as an initiator, triggers the epsilon -CL open ring polymerization, polymerized into a good biocompatibility and biodegradable polyhexyl polyhexyl polyhexyl polyhexyl (PCL-PEG-PCL, PCEC) two Pro three block copolymers as the carrier material, and the chemical treatment widely used in clinical treatment. Drugs - doxorubicin and taxol hydrochloric acid as a model drug, folic acid as a target ligand to construct a polymer targeted nano vesicle with a target of folic acid and double loaded drugs. In this vesicle, paclitaxel is distributed in the hydrophobic membrane and adriamycin hydrochloric acid is wrapped in the hydrophilic cavity. The results show that the mass fraction of the hydrophilic PEG segment of the two amphiphilic three block copolymer PCL-PEG-PCL can be formed when the mass fraction of the hydrophilic PEG segment is about 33%. The cell uptake studies showed that the endocytosis of the folic acid targeted double loaded polymer vesicles (FA-PTX-DOX-PS) in BEL-7404 cells expressed by folic acid receptor was significantly higher than that of the double loaded polymer vesicles (PTX-DOX-PS) without folic acid targeting. Cytotoxicity test in vitro showed that FA-PTX-DOX-PS The toxicity of free paclitaxel and doxorubicin was effectively reduced and the tumor growth was inhibited more effectively than PTX-DOX-PS. In vivo fluorescence imaging results showed that FA-PTX-DOX-PS showed highly effective targeting and could accumulate in the tumor. In addition, in vivo antitumor studies showed that the clinical "cocktail therapy" was free to the drug. FA-PTX-DOX-PS has significant tumor targeting, stronger tumor suppressor effect and effective overcoming the systemic toxic side effects of "cocktail therapy" in clinical. Therefore, folic acid targeted double drug loaded polymer nanoscale is a potential delivery of multiple chemotherapeutic drugs for tumor efficiency, targeting and synergistic treatment. Nanoscale preparation.
【学位授予单位】：北京协和医学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R943;R96

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