Diagnostic applications of gastric carcinoma cell aptamers in vitro and in vivo

• We select four new aptamers targeting human gastric tumor cells using “Cell-SELEX”.
• Aptamers can distinguish human gastric tumor tissues from the normal tissues.
• Aptamer-functionalized fluorescent magnetic nanospheres capture 93% cancerous cell.
• Aptamer-functionalized fluorescent magnetic nanospheres release 70% cancerous cell.
• Aptamer probe can specific detect target gastric tumor cells in vitro and in vivo.

Gastric carcinoma is the most malignant tumor. Due to lacking of efficient means to diagnose the cancer at the early stage, it is necessary to develop effective molecular probes for early diagnosis and treatment. We have selected aptamers with high specificity and affinity against SGC7901 cells by cell-SELEX (Systematic Evolution of Ligands by Exponential Enrichment) method, which shown important clinical applications: (1) Specific recognize human gastric tumor tissues compared to the normal tissues. (2)When used to capture cancerous cells, the aptamer-functionalized fluorescent-magnetic nanospheres (FMNS) could specifically capture 93% target cancer cells and about70% target cells can be released. (3) The aptamer probe displayed a quenched fluorescence in the absence of target cancer cells and went through a conformational transformation upon binding to target cancer cells that induced fluorescence. (4) The aptamer probe could target gastric tumors transplanted into mice with obvious fluorescence. The newly generated aptamers hold great potential in early cancer diagnosis.

We demonstrated that using cell-SELEX strategy, the selected aptamers could specifically recognize human gastric tumor tissues compared to the normal tissues. When the selected aptamers were conjugated with fluorescent-magnetic nanospheres (FMNS) to capture cancer cells, they showed high captured and release efficiency. The newly designed aptamer probe underwent a conformational change upon binding to the target cancer cell, which resulted in the activation of a fluorescence signal. Flow cytometry assays revealed that the aptamer probe was specifically activated by the target cancer cells and showed high sensitivity for SGC7901 cells. Furthermore, the aptamer probe was able to specifically target the SGC7901 tumor site and exhibited a very bright fluorescence signal within 15 min after injection. The aptamer probe strategy hold a great potential to design molecular probes for in vivo cancer imaging with high sensitivity and specificity.Figure optionsDownload as PowerPoint slide