測試自動化微流體系統篩選獲得之適體辨識細胞之專一性

癌症是台灣十大死因之首，許多癌症仍缺乏方便、快速的早期篩檢方式。本研究探討近年發展出具有高專一性的新興臨床檢測用材料適體（Aptamer）進行十大癌症中之大腸癌與卵巢癌的辨識。適體為單股核酸，經由指數增幅型系統性配子演化法（Systematic evolution of ligands by exponential enrichment, SELEX）可篩選出具有特殊立體結構能與標的物具專一鍵結能力之適體。本研究與動力機械工程學系李國賓老師實驗室合作，利用其所開發之自動化微流體適體篩選系統篩選出大腸癌適體（HCT-8-17、HCT-8-34）與卵巢癌適體（Tx-Ov-02rc）。利用大腸癌細胞HCT-8與卵巢癌細胞OVCAR3、OVCAR4與小鼠纖維母細胞Balb/c 3T3進行適體鍵結試驗，驗證適體鍵結標的物之能力與專一性。本研究並誘導免疫缺損小鼠生成腫瘤，將Cy5螢光標定適體以尾靜脈注射方式注入小鼠體內，觀察適體於動物體內代謝途徑與腫瘤鍵結能力。結果顯示Tx-Ov-02rc對於卵巢癌細胞OVCAR3有較高的專一性，也可觀察到其鍵結於活體腫瘤。其餘適體則較不具專一性。另外，李國賓老師實驗室也開發出胜肽自動化微流體篩選系統並利用此系統篩選出大腸癌胜肽（HOLC-1、HOLC-2）與卵巢癌胜肽（Tp-Ov-3-1）。我們同樣以鍵結試驗確認經自動化系統篩選出之胜肽對標的物的專一性。試驗結果發現HOLC-1對大腸癌細胞HCT-8有較高的專一性；HOLC-2與Tp-Ov-3-1胜肽對細胞之專一性較低。同時，我們將胜肽Tp-Ov-3-1共軛紅螢光蛋白mCherry，觀察攜帶大分子之胜肽是否會影響其鍵結細胞之能力。由胜肽鍵結試驗結果發現攜帶mCherry之胜肽並不影響其鍵結細胞能力，未來，可將mCherry更換為具毒殺細胞能力之蛋白生成抗癌胜肽。綜合上述，適體與胜肽具有成為新興癌症篩檢試劑與抗癌藥物之潛力。

關鍵字

適體；大腸癌；卵巢癌；自動化微流體系統；指數增幅型系統性配子演化法；癌症篩檢

並列摘要

Cancer is the number one cause of death in Taiwan. Most of cancers have no convenient, rapid screening method. In this study, we evaluated the specificity of novel clinical cancer screening material, aptamer, in detecting colon cancer and ovarian cancer, which are among top ten cancers. Aptamers are single-stranded nucleic acids that specifically bind to target molecules by their 3-dimentional structure and can be selected through systematic evolution of ligands by exponential enrichment (SELEX) procedure. This study is a collaboration with Prof. Lee, Gwo-Bin who developed an automatically microfluidic aptamer system for screening several aptamers to detect colon cancer (HCT-8-17 and HCT-8-34) and ovarian cancer (Tx-Ov-02rc). First, we verified the specific binding between aptamers and HCT-8 colon cancer, OVCAR3 ovarian cancer and Balb/c 3T3 fibroblasts by aptamer binding assay. We found that ovarian cancer aptamer Tx-Ov-02rc can bind to OVCAR3. Furthermore, we induced tumor on an immunodeficient mouse and injected Cy5-labelled aptamers into the mouse via tail vein. The result shows that Tx-Ov-02rc can specifically bind to OVCAR3 in vitro and in vivo. Prof. Lee’s lab also developed an automatically microfluidic peptide screening system to screen several peptides including colon cancer-targeting peptides (HOLC-1 and HOLC-2), an ovarian cancer-targeting peptide (Tp-Ov-3-1). We evaluated these peptides’ specificity by peptide binding assay and found that HOLC-1 can bind to HCT-8. Finally, we conjugated red fluorescent protein mCherry to the peptide, Tx-Op-3-1. In order to investigate whether macromolecule will influence the binding ability of peptides. The result showed that mCherry-conjugated peptides possessed specific binding ability to ovarian cancer cells. In the future, we can replace mCherry protein into a protein with cell-killing ability to generate a cancer-specific drug. To sum up, aptamer and peptide can be a potential cancer diagnostic reagent and anti-cancer drug.

並列關鍵字

Aptamer ； Colon cancer ； Ovarian cancer ； Automatically microfluidic system ； SELEX ； Cancer screening

參考文獻

1 Chiang, C. J., Chen, Y. C., Chen, C. J., You, S. L. & Lai, M. S. Cancer trends in Taiwan. Jpn. J. Clin. Oncol. 40, 897-904 (2010).

2 Mandel, J. S., Bond, J. H., Church, T. R., Snover, D. C., Bradley, G. M., Schuman, L. M. & Ederer, F. Reducing mortality from colorectal cancer by screening for fecal occult blood. New Engl. J. Med. 328, 1365-1371 (1993).

3 Arbyn, M., Buntinx, F., Ranst, M. V., Paraskevaidis, E., Martin-Hirsch, P. & Dillner, J. Virologic versus cytologic triage of women with equivocal Pap Smears: a meta-analysis of the accuracy To detect high-grade intraepithelial neoplasia. JNCI-J. Natl. Cancer I. 96, 280-293 (2004).

4 Lauterbur, P. C. All science is interdisciplinary—from magnetic moments to molecules to men (Nobel Lecture). Angew. Chem. Int. Edit. 44, 1004-1011 (2005).

5 Gambhir, S. S. Molecular imaging of cancer with positron emission tomography. Nat. Rev. Cancer 2, 683-693 (2002).

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測試自動化微流體系統篩選獲得之適體辨識細胞之專一性

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