Evaluation of cell-recognizing specificity of aptamers selected by a microfluidic SELEX platform

• Main Authors: Wang, Kuan-Chieh, 王冠傑
• Other Authors: Chang, Hwan-You
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/tansy2

碩士 === 國立清華大學 === 分子醫學研究所 === 105 === 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.