製備多功能奈米微胞載體應用於K-RAS基因突變之大腸癌細胞結合EGFR標靶性並進行合併基因與化學治療之毒殺與評估

Synthesis of Brush-like p(DMAEMA-co-PEGMEA)-b-PCL as K-RAS siRNA and SN-38 Carrier for Dual Genetic and Chemo- therapies with EGFR Targeting in K-RAS Mutation HCT-116 Colon Cancer Model

林塘閔(Tang-Min Lin)

指導教授 ： 謝銘鈞

國立臺灣大學/工學院/醫學工程學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.10434

摘要

近年來，惡性腫瘤已為國人十大死因之首，然而,大腸癌位居惡性腫瘤耗發率之前三名，可見對於大腸癌之診斷與治療之重要性，為了實現更良好的大腸癌治療，高分子奈米藥物載體被廣泛運用在藥物傳輸系統來治療癌症，利用雙親性高分子包覆化療藥物或光感藥物,進行癌細胞毒殺並減緩單純施予藥物對正常細胞之毒性與副作用產生，然而現今之藥物載體並非僅限於藥物傳輸，基因治療與標靶治療也於近年來蓬勃發展。奈米藥物載體之優點為，可利用藥物包覆減低非作用目標之細胞攝取，再者，奈米級載體可藉由其粒徑極小之特性產生增強通透性與延遲效應(EPR effects)進而達成在腫瘤組織之被動標靶(passive targeting)的特性，增強藥物累積量與減少藥物之使用量，除此之外，利用核糖核酸干擾技術(RNAi)抑制特定基因之表現，對於某些疾病有良好的治癒能力，合併基因治療與化學治療於癌症治癒上可以達到加成效應也為現今熱門研究的方向，特別的是，標靶治療為現今癌症治療之方法之一，對於惡性腫瘤有顯著抑制增長的成果，將標靶藥物修飾於奈米藥物載體外圍並整合基因與化學治療之奈米藥物載體，可以相對增加癌症細胞攝取藥物之專一性，並增強毒殺腫瘤之能力，形成多功能之藥物載體。
在人類大腸癌細胞(HCT-116)中,其K-ras基因為突變型，導致其長期處於活性狀態，不受上游上皮生長因子受體(EGFR)之控制使其下游蛋白持續磷酸化，進而造成癌細胞增生與轉移，因此，本篇碩士論文將利用帶正電之高分子p(DMAEMA-co-PEGMEA)-b-PCL與mal-PEG-b-PCL以特定比例形成混和型奈米微胞載體，並利用靜電作用吸附帶負電之K-ras siRNA，以及利用疏水端性質包覆化療藥物SN-38，再者，將奈米微胞表面共價鍵結標靶藥物Erbitux®以達成具有標靶能力同時合併基因與化學治療之多功能型奈米藥物微胞載體，在物理性質方面，粒徑大小位於200-300nm左右，藥物包覆率也可達成60%以上，在臨界微胞濃度值方面,表現此奈米微胞在大量稀釋環境中很穩定並且在於含有血球與蛋白之環境中，安全無虞，除此之外，在細胞攝取量、細胞毒性與轉染效率等觀察，可發現多功能性微胞皆有較佳之治療能力，即為一高潛力之奈米藥物載體，對於癌症治癒之療程與方法有所增進，並希望對於生物醫學領域有些許貢獻。

關鍵字

基因治療 ； 化療藥物 ； 標靶治療 ； 癌症 ； 奈米藥物載體

並列摘要

Recently, cancer has been the top reasons of people’s death and colorectal cancer would be the most common diseases of all human cancers, so that the examinations and therapies of colon cancers would be an important thing. For better ways of curing cancers, polymeric nanoparticles were widely used in the field of drug delivery systems. For example, amphiphilic micelles were carried out to encapsulate hydrophobic anticancer drugs or photosensitizers to reduce the cytotoxicity and side effects to normal cells when anticancer drugs were administered directly. The advantages of nano-carriers could be generalized in the following reasons. Nano-sized vectors could reach enhanced permeability and retention (EPR) effects in tumor cells. The passive target causes of accumulations of drugs at tumor sites and could reduce the amount of anticancer drugs used. However, drug delivery systems not only includes drug delivery but gene therapy which is one of the popular methods and well developed in the decades. According to the reasons, if combine chemotherapy with gene therapy, maybe the abilities of killing cancers would be additive. Another, targeting therapy is one widely used way of curing cancers recently and was found to be an efficient method. Hence, we could integrate targeting molecules by surface modifications of micelles and mult-functional nano-medicine was made to reach specific killing of cancers.
In human colorectal cancer cells, HCT-116 cells, K-ras gene was observed mutant, leading to its staying in an activated state all the time. They become uncontrollable to its up-streams such as EGFR and make down-stream proteins continuously phosphorylated. Cells will keep migrating, surviving, and proliferating. Hence, in this study, positively charged polymers p(DMAEMA-co-PEGMEA)-b-PCL were synthesized and its mixture with mal-PEG-b-PCL were formed. Moreover, K-ras siRNA was attached on micelles by electrostatic interactions. Hydrophobic anticancer drug, SN-38, was loaded in the core of micelles, and furthermore, the antibody, C225 was conjugated onto the maleimide group of micelles by covalent bonds to reach genetic and chemo-therapies with targeting at the same time. In physical and chemical properties, the sizes were about 200 nm to 300 nm, and the drug encapsulated efficiency would approximately over 60 %. Nevertheless, the critical micelles concentrations (CMC) were all small enough to be stable in mass dilutions. Particularly, the micelles are safe especially in the environments filled with blood cells and proteins. Moreover, the cell viabilities, cell uptake, and even gene transfection efficiencies were all in good results, which make the vectors to be a potential nano-carrier in curing cancers. Hope that the research would reach little progress in the field of bio-medical engineering.

並列關鍵字

SN-38 ； Cetuximab ； K-ras gene ； micelle ； colon cancer

參考文獻

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