功能化介孔二氧化硅纳米载药体系在肿瘤诊疗中的应用与机制研究

发布时间：2018-03-31 16:37

  本文选题：介孔二氧化硅　切入点：金属配合物　出处：《暨南大学》2016年博士论文

【摘要】：恶性肿瘤严重危害人类健康,肿瘤治疗已经成为当前医学研究领域所面临的一个重大挑战。在目前的治疗中,化疗在肿瘤的综合治疗中占主导地位,但是化疗药物在肿瘤治疗过程中所引起的全身性毒副作用严重限制了其临床使用。近年来,纳米技术的出现为抗肿瘤药物设计提供了新思路。纳米技术融合生物学和纳米工程学,在肿瘤成像、肿瘤诊断和肿瘤靶向治疗等方面展现出了广阔的应用前景。纳米体系通过靶向性修饰,能将药物有针对性地递送到病变组织,提高治疗效果并减少对正常组织的毒副作用。目前,已有大量的纳米材料作为纳米载药体系而被广泛关注。其中,介孔二氧化硅纳米材料由于其具有明显的优势而被作为一种理想的载药体系。在本课题中,我们通过对该纳米材料进行功能化修饰,并作为化疗药物的传递系统,实现其在肿瘤治疗中的应用。具体研究结果如下:1、尽管金属配合物表现出潜在的抗肿瘤活性,并表现出巨大的前景,但是它们仍然存在不可避免的细胞毒性、细胞摄取率低以及不具有选择性等缺点。为了解决金属配合物的这一难题,在本课题中,我们设计合成出一种RGD多肽修饰的靶向二氧化硅纳米体系作为该类金属配合物的传递系统,实现了药物对肿瘤细胞和正常细胞之间的选择性,从而提高了药物抗肿瘤活性,并降低其毒副作用。RGD的修饰能大大提高该纳米体系通过整合素介导细胞吸收,从而实现药物对肿瘤细胞的靶向性。此外,该靶向纳米载药体系主要是激活了肿瘤细胞的死亡受体通路,进一步诱导ROS在细胞内的累积,从而引起DNA损伤,激活了p53、AKT以及MAPKs信号通路而诱导细胞凋亡,阐明了该纳米体系的抗肿瘤分子机制。2、肿瘤血管为肿瘤微环境提供必要的养料和氧气,对肿瘤的发生、发展和代谢起了至关重要的作用。因此针对血管形成的某些因子及其关键步骤进行干预可有望切断肿瘤血供及其转移途径,对肿瘤的治疗和防止肿瘤向远处转移有重要意义。因此,在该部分实验中,我们基于肿瘤细胞与血管内皮细胞的生物化学相似性,设计了双重靶向肿瘤与血管细胞的纳米体系,通过抑制血管细胞的生长来切断肿瘤细胞增殖所需营养,同时直接诱导肿瘤细胞凋亡,最终实现抑制肿瘤与血管生成。实验结果发现,该双靶向纳米体系在体内外双肿瘤模型和细胞共培养中,对肿瘤组织和肿瘤细胞表现出很高的选择性,并能有效的诱导肿瘤细胞凋亡,而减少对正常细胞的毒性。此外该纳米体系能通过激活p53信号通路诱导肿瘤细胞凋亡,从而抑制肿瘤生长和血管生成。3、目前,肿瘤的治疗手段仍然以手术切除、放射性治疗以及化学药物治疗为主。放射线虽然对肿瘤细胞具有较直接的杀死和抑制效果,但是由于肿瘤处于低氧环境中,使得单独的放疗无法彻底根除肿瘤细胞,反而使肿瘤对x射线产生耐受而不敏感。因此,设计合成一种高效低毒的放疗增敏剂并发挥其与放疗的协同作用具有重要意义。在该部分研究中,我们将二氧化硅纳米材料负载一种含硒氨基酸,同时将细胞穿膜肽和转铁蛋白共价连接到高分子聚合物plga上,并将其对二氧化硅纳米载药体系进行包裹,得到一种多功能纳米载药体系,实现对放疗的增敏效果。实验结果发现,该纳米体系能有效的协同放疗增强x射线诱导的肿瘤细胞凋亡,并且主要是激活细胞内死亡受体介导的信号通路。此外,在x射线的照射下,sec@msns-tf/tat能促进细胞内ros的大量累积,从而激活下游akt和mapks信号通路,并引起细胞内dna损伤介导的p53信号通路的激活,同时能抑制细胞的自我损伤修复功能,最终诱导细胞凋亡。sec@msns-tf/tat同能有效的通过激活体内肿瘤组织中p53介导的细胞凋亡,从而抑制小鼠体内荷瘤生长,且在有效抗肿瘤浓度下对小鼠无明显毒性,说明所设计合成的多功能纳米体系sec@msns-tf/tat能作为一种高效低毒的放疗增敏剂实现体内外肿瘤同步放化疗的应用。4、由于纳米材料特殊的尺寸和形貌,使得它相比于宏观尺度的材料具有很多特殊的效应(小尺寸效应、表面效应、宏观量子隧道效应等),并赋予了纳米材料广泛的应用前景。因此,在本课题研究中,我们通过对碱性催化剂类型和浓度的改变合成出不同尺寸大小的介孔二氧化硅纳米粒子,并研究了三种不同尺寸(20nm、40nm和80nm)纳米载药体系对脑胶质瘤细胞的吸收、停留以及渗透进入血脑屏障能力的影响。实验结果发现,这三种不同尺寸的靶向纳米体系dox@msns能显著提高单独dox诱导脑胶质瘤细胞产生过量的ros,从而增强其诱导肿瘤细胞凋亡的程度,提高了dox的抗肿瘤效果,同时尺寸为40nm的纳米体系表现出更优的效果。此外,这三种不同尺寸靶向纳米药物能有效地穿透血脑屏障,并被脑胶质瘤细胞吸收,提高单独dox的抗肿瘤效果。同时能有效地摧毁脑胶质瘤细胞的血管拟态生成,从而增强其抗肿瘤效果。该纳米药物对肿瘤球生长是尺寸依赖性的,DOX@MSNs纳米体系对肿瘤球的渗透作用明显强于单独DOX,从而增强其对肿瘤球生长的抑制作用。综上所述,介孔二氧化硅纳米材料作为一种理想的化学药物载体,通过靶向修饰能有效的提高化疗药物的抗肿瘤活性以及对肿瘤细胞和正常细胞的选择性,进而减少药物的毒副作用。这种多功能纳米体系能同时实现对抗体内外肿瘤生长和血管生成,并能作为一种高效低毒的放疗增敏剂协同X射线提高抗肿瘤效果。并且,在本课题的研究中,我们也对这类靶向纳米体系的体内外抗肿瘤作用机制进行了清楚的阐述。因此,我们认为:本课题的工作为进一步开发靶点清楚、作用机制明确的新型靶向纳米药物或先导物在肿瘤诊疗中的应用提供科学依据。
[Abstract]:Malignant tumor serious harm to human health, cancer treatment has become a major challenge in the field of Medical Research Institute. In the present treatment, chemotherapy is dominant in tumor therapy, but the side-effect of chemotherapy caused by tumor in the treatment of severe systemic limiting the clinical use of in recent years. Here, the emergence of Nanotechnology provides new ideas for anticancer drug design. Nano biology and engineering integration of nanotechnology, in tumor imaging, tumor diagnosis and tumor targeting therapy has shown a broad application prospect. Nanoparticles modified by target, can be targeted drug delivery to disease the organization, improve the therapeutic effect and reduce the side effects on normal tissues. At present, there are a large number of nano materials as nano drug delivery system has been widely concerned. Among them, Kong Eryang referred to silicon Nano materials because of its obvious advantages have been used as an ideal drug loading system. In this paper, we through functionalization of the nano materials, and as a drug delivery system for its application in the treatment of tumor. The results are as follows: 1, although the performance of metal complexes the potential antitumor activity, and shows great prospect, but they still have the inevitable cytotoxicity, cellular uptake rate is low and is not selective and other shortcomings. In order to solve this problem with metal objects, in this article, we designed and synthesized a RGD polypeptide modified silica nanoparticles targeting transfer system as a system of this kind of metal complexes, the selective drugs between tumor cells and normal cells, thus improving the drug antitumor activity, and reduce the side effects of.RGD Modification can greatly improve the nano system through integrin mediated cell absorption, so as to realize the drug targeting of tumor cells. In addition, the targeted nano drug delivery system is the activation of the death receptor pathway of tumor cells and further induce ROS accumulation in cells, the damage caused by DNA, the activation of p53. AKT and MAPKs signaling pathway and induce cell apoptosis, and discusses the system of anti nano molecular mechanism of tumor.2, tumor vascular tumor microenvironment provide the necessary nutrients and oxygen, and the occurrence of cancer, development and metabolism played a crucial role. Therefore some angiogenic factor and key steps of intervention is expected to cut off the blood supply of the tumor and its metastasis pathway, the treatment of tumors and to prevent tumor metastasis has important significance. Therefore, in this part of the experiment, we based on tumor cells and endothelial cells Biochemistry cell similarity design double targeting tumor cells and blood vessels in the nano system, by inhibiting the growth of vascular cell proliferation of tumor cells to cut off the needed nutrients, and directly induce apoptosis of tumor cell, and ultimately inhibit tumor and angiogenesis. The experimental results showed that the dual targeting nanoparticles in vivo double tumor model and cell culture, high selectivity of tumor tissues and cells from the tumor, and can effectively induce the apoptosis of tumor cells, and reduce the toxicity to normal cells. In addition the nano system can induce the apoptosis of tumor cells to activate the p53 pathway to inhibit tumor growth and angiogenesis of.3, at present the treatment of tumor, still with surgical resection, radiotherapy and chemotherapy. Although radiation has a direct effect on killing and inhibiting tumor cells, but Is due to the tumor in the hypoxic environment, so that the separate radiotherapy is unable to completely eradicate tumor cells, but the tumor of X ray resistant and not sensitive. Therefore, has important significance to design and synthesis of a synergistic effect of radiotherapy with high efficiency and low toxicity sensitizer and play with radiotherapy. In this study, we will silica nano material load for selenium containing amino acid, while the cell penetrating peptide and transferrin covalently attached to the polymer PLGA, the silica nanoparticles delivery system package system of a multifunctional nano drug carrier, to achieve the effect of increasing sensitivity to radiotherapy. The experimental results showed that the nano system can effectively the synergistic enhancement of tumor cell apoptosis radiotherapy induced by X irradiation, and mainly activate intracellular signaling pathway mediated by death receptor. In addition, the X - ray irradiation, sec@ msns-tf/tat To promote the accumulation of intracellular ROS, Akt and MAPKs to activate downstream signaling pathways, and activate intracellular p53 signaling mediated DNA damage, and can inhibit the cell self repair function, ultimately inducing apoptosis of.Sec@msns-tf/tat apoptosis and effectively through activation of in vivo tumor tissues mediated by p53. In order to inhibit tumor growth in mice, and the effective anti-tumor concentration in mice without obvious toxicity. The design of multifunctional nano system sec@msns-tf/tat synthesis can be used as a.4 synchronous radiation sensitizer to achieve high efficiency and low toxicity in vivo tumor chemotherapy, due to the size and morphology of nano materials, making it compared to the macro scale material has many special effects (small size effect, surface effect, quantum tunneling effect and so on), and given the nano materials should be widely With prospects. Therefore, in this research, we based on the alkaline catalyst type and the change of the concentration of the synthesis of mesoporous silica nanoparticles of different sizes, and studied three different sizes (20nm, 40nm and 80nm) nanoparticles delivery system on glioma cell absorption, and penetrate into the blood effect of residence brain barrier ability. The experimental results showed that the three different sizes of targeted nano dox@msns system can significantly improve the DOX overproduction of ROS glioma cells induced by, so as to enhance the induction of tumor cell apoptosis degree, improve the antitumor effect of DOX, while the size of 40nm nanoparticles showed better the effect. In addition, the three different sizes of targeted nano drug can effectively penetrate the blood-brain barrier and absorbed glioma cells, enhance the antitumor effect of DOX alone and can effectively destroy the brain. Vasculogenic glioma cells, thereby enhancing the anti-tumor effect. The nano drugs on the growth of tumor sphere is size dependent. The penetration effect of nano DOX@MSNs system on tumor sphere was stronger than DOX alone, thereby enhancing its inhibitory effect on tumor growth of the ball. To sum up, mesoporous silica nanoparticles as an ideal chemical drug carrier, can enhance the antitumor activity of chemotherapeutic drugs is effective and selective for tumor cells and normal cells to modified by target, thereby reducing the side effects of drugs. The multifunctional nano system can be generated at the same time on the growth and vascular tumors and antibody, as an efficient radiotherapy low toxicity sensitizing agents improve the anti-tumor effect of collaborative X ray. Also, in this research, we also carry on this kind of targeting nanoparticles in vitro and in vivo antitumor mechanism Therefore, we believe that our work will provide a scientific basis for further development of new targeted nano drugs or precursors with clear targets and mechanisms in the diagnosis and treatment of tumors.

【学位授予单位】：暨南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R730
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本文编号：1691556