The Screening and Application of Aptamers against SCUBE3

Abstract

Signal peptide-CUB-EGF-like domain-containing protein 3 (SCUBE3) a secreted glycoprotein has been found to be overexpressed in lung cancer tumor tissues and correlated with the invasive ability of lung cancer cells Previous study has showed that SCUBE3 may have a critical role with TGF-β and control tumorigenesis via the TGF-β receptors-Smad2/3 pathway Here our hypothesis is SCUBE3-specific inhibitors may have potential therapeutic applications for lung cancer Aptamers are short DNA or RNA fragments that can form complex secondary structures to have specific ability for its target molecule In this study we used recombinant SCUBE3 proteins to screen single-stranded DNA aptamers by systematic evolution of ligands by exponential enrichment SELEX and identified a SCUBE3-specific aptamer S3-A1 We found that biotinylated S3-A1 specifically binds to SCUBE3 proteins with an around 18nM dissociation constant S3-A1 also preferentially binds to SCUBE3-overexpred cells compared with control cells Treatment of S3-A1 on lung cancer cells seemed to increase phosphorylation of Smad2 implying that S3-A1 might promote SCUBE in TGF-β receptors-Smad2/3 pathway activation By wound-healing assay we found that S3-A1 promoted SCUBE3-induced cancer cells migration Next we will further investigate the influences of S3-A1 on SCUBE3-mediated biological functions of cancer cells and vascular endothelial cells In conclusion S3-A1 may affect SCUBE3/TGFβR/Smad2 signaling by directly binding SCUBE3 and regulate cancer progression and it also inhibits in vitro tube formation of vascular endothelial cells

Date of Award	2014 Sept 2
Original language	English
Supervisor	Yuh-Ling Chen (Supervisor)