Title: Novel tumor marker discovery based on automated Aptamer screening

Abstract

Aptamer is a new type of nanomaterial that plays an important role in tumor diagnosis and treatment. It can bind to proteins on the cell surface with specific recognition ability. Aptamers have three major advantages over antibodies. First, they are smaller and less likely to cause immune clearance; Second, the aptamer has a relatively simple structure, so it has a shorter synthesis cycle and lower synthesis cost; Third, aptamers can be modified by simple reactions, so as to adapt to various applications such as in vivo imaging and targeted drug delivery. Since nucleic acid aptamers can specifically bind to unknown targets when the specific context of tumor cell surface proteins is unclear, they can be used to discover novel tumor surface markers. In this experiment, we obtained the nucleic acid aptamers of nasopharyngeal carcinoma cells (5-8F cells) through an automated screening flow from an autonomously built nucleic acid aptamer screening instrument. We then performed biotin modification on the nucleic acid aptamer, incubated it with 5-8F cells, and used streptavidin magnetic beads to grasp the nucleic acid aptamer bound to specific membrane proteins from the lysed cell fluid. Preliminary membrane protein information was next obtained by sorting out specific proteins by electrophoresis, contrasting with total protein electrophoresis results, and identifying proteins. Then we analyzed several selected membrane proteins from their spatial distribution, property analysis, and changes in binding capacity after siRNA silencing. Through this experiment, we identified a tumor marker for 5-8F cells and provided a new idea for novel tumor marker discovery.