Screening and Study of Aptamer Based on Gastric Cancer Cell Culture Medium

Gastric Cancer (GC) is one of the fifth most malignant tumors in the world and the third leading cause of cancer-related deaths. At present, one of the methods to diagnose gastric cancer patients is screening for gastric cancer tumor markers. However, the specificity and detection rate of existing tumor markers are low. Aptamer, also known as chemical antibody, is a kind of single-stranded oligonucleotide (DNA or RNA) obtained by SELEX. It is widely used in the diagnosis of new diseases and as a molecular probe for treatment. This study used Med-SELEX technology, using agarose magnetic beads as the carrier, and cancer culture medium as the screening target. APT-1 specific to gastric cancer cell culture medium was screened out from random library through q-PCR real-time monitoring and screening process, and its affinity and specificity for gastric cancer serum were verified by subsequent q-PCR and quantum dot methods. Serum stability test and cytotoxicity test proved its practicability. APT-1 is not only of great significance for the early diagnosis of gastric cancer and the construction of targeted drug delivery system for gastric cancer, but also may be used as a probe to discover new tumor markers for gastric cancer.