奈米技術應用於癌症醫學檢測暨治療之探討

Abstract

近年來，隨著科技不斷的發現與技術上的突破，奈米科技的發展日益蓬勃，而相關之應用也更加多元與精細，然而在現代社會中，對於健康保健及癌症醫療投入更多的重視與關切之際，奈米技術應用於癌症之預防檢測或及其醫療，更加的顯示出其重要性與急迫性。為了進一步研究奈米技術應用於癌症醫學之檢測暨治療，本研究將分成兩章節進行探討。 第一章節主要為在眾多的血液細胞下存在的微量T細胞提出了一種快速，靈敏的檢測方法，該方法涉及同時檢測2種原生於輔助性T細胞之生物標記物。將其一之生物標誌物與本研究開發之具免疫功能性磁性奈米粒子進行免疫辨識結合，從而使特定的輔助T細胞得以由眾多的血液混合細胞群中分離，再應用酵素結合免疫吸附分析(ELISA)方法，加以分析檢測該特定之輔助T細胞。本研究結果顯示出了，具有免疫功能性之磁性奈米粒子不但具有著高特異性，可將單獨特異的T輔助細胞於眾多的血液混合細胞群中辨識暨分離，再輔以酵素結合免疫吸附分析方法，使此應用得以高效能同時檢測出特定之稀有細胞。即便甚至在相對極低量之特定稀有細胞時，依然仍可偵查檢測出該細胞，因此本研究所提出的應用優點包括，可檢測於極低量的特定之稀有細胞、檢測方式易於製備，成本相對低廉，檢測迅速和高靈敏度等等。爾後當技術成熟時，期望未來將可推及應用於腫瘤細胞在腫瘤早期階段的診斷或預後的評估，進而掌握往後醫學治療之先機。

第二章節為研究慢性骨隨性白血病(CML)癌症醫學治療之探討，CML是多能造血性骨隨幹細胞的惡性腫瘤病變，其特徵在於不受控制的增殖與過度的侵犯骨髓而嚴重的影響了人體造血功能之機制與喪失，然而就其癌化的分子機制角度而言，是由於這些病變幹細胞具有Ph1染色體，造成了致癌基因bcr-abl的產生，進一步生成了BCR-ABL這種具有酪胺酸脢過度異常活性的融合蛋白。在此類惡性腫瘤的細胞內，有很多證據顯示出了BCR-ABL會過度的刺激活化細胞訊息並且防止細胞進行細胞程式性凋亡，進一步的使得有些抗腫瘤治療劑，例如紫杉醇(paclitaxel)，面臨著效果不良或無效的窘境，因此在開發治療CML的化學療法上，合併處理酪胺酸脢抑制劑就扮演著相當重要的角色。在這章節研究中我們利用了新穎的小分子酪胺酸脢抑制劑tyrphostin AG1024研究探討是否可降低CML細胞株K562對於抗癌藥物paclitaxel的抗性，並且增強細胞程式性凋亡的能力。結果我們發現在合併paclitaxel輔以處理不同濃度的tyrphostin AG1024經過24小時之後，細胞的增生受到了抑制且有顯著的下降，並且BCR-ABL的表現量降低了，同時其抗凋亡因子如Bcl- 2和Bcl-xL等等抗凋亡蛋白也隨之下降，更進一步的觀察到了在合併paclitaxel處理之早期24小時的時候，即可有效的誘發細胞的程式性凋亡能力。因此本研究顯示，在tyrphostin AG1024與paclitaxel兩者合併的組合治療模式下，可明顯的顯示出paclitaxel抑制癌細胞增殖暨抗癌的效果，為將來奠定了paclitaxel應用於CML癌症化學治療之基石。

In the first chapter presents a rapid and sensitive method for detecting cancer cells occurring at low concentration. The method involves the simultaneous detection of 2 biomarkers of T helper cancer cells. One biomarker conjugates with immunofunctionalized magnetic nanoparticles (MNPs), enabling the separation of the T helper cells from a mixed population of cells. The other biomarker is used for detection during ELISA analysis. The specific T helper cells can be quantified according to their ELISA absorbance values following magnetic separation. The experimental results demonstrate that immunofunctionalized MNPs can function as magnetic sensors and separate specific T helper cells from a mixed population with high efficiency and high specificity. Coupled with the ELISA technique, the immunofunctionalized MNPs can simultaneously detect rare cells. Results indicated increasing absorbance with increasing T cell number (from 10 to 106). The total detection time was less than 15 minutes, even at a low T cell count. The advantages of the proposed method for detecting specific cells at low concentration include ease of preparation, low cost, rapid detection, and high sensitivity. The proposed system can be adopted to detect circulating tumor cells in early tumor stages for diagnostic or prognostic purposes.

In the second chapter illustration that chronic myelogenous leukemia is a clonal malignancy of the pluripotent hematopoietic stem cells that is characterized by the uncontrolled proliferation and expansion of myeloid progenitors. Myeloid progenitors express the fusion oncogene BCR-ABL, which has uncontrollable activity in malignant cells and prevents the cell apoptosis caused by some antineoplastic agents, such as paclitaxel. Targeting these abnormalities by blocking the tyrosine kinase enzymes of BCR-ABL is a promising approach for chronic myelogenous leukemia therapy. The effects of the tyrosine kinase inhibitor AG1024 were evaluated with regard to the regulation of BCR-ABL expression, inhibition of cell proliferation, and enhanced paclitaxel-induced apoptosis in BCR-ABL-expressing K562 cell lines. AG1024 downregulated the expression of BCR-ABL and anti-apoptosis factors, such as Bcl-2 and Bcl-xL, which were present in K562 cells. Moreover, the combination of AG1024 with paclitaxel inhibited cell proliferation and enhanced paclitaxel-induced apoptosis within 24 h. In summary, the present study shows that the combination of AG1024 with paclitaxel inhibited model cancer cell proliferation, suggesting a new use of paclitaxel-based chemotherapy for cancer control.