Analytical Sciences

A Catalytic DNA Probe with Stem-loop Motif for Human T47D Breast Cancer Cells

Fei GAO,*1,*2 Feng LIU,*2 Jing ZHENG,*2 MeiYun ZENG,*4 and Yuyang JIANG*1,*2,*3

*1 Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China
*2 The Ministry-Province Jointly Constructed Base for State Key Lab-Shenzhen Key Laboratory of Chemical Biology, the Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong, 518055, P. R. China
*3 Department of Pharmacology and Pharmaceutical Sciences, School of Medicine, Tsinghua University, Beijing 100084, P. R. China
*4 Shenzhen Kivita Innovative Drug Discovery Institute, Shenzhen, Guangdong 518055, P. R. China

In vitro selection methods allow for isolation of DNAzymes (catalytic DNAs) from random DNA pools. Here we describe a fluorogenic DNAzyme, LYF5, isolated using a double-random selection approach: a random DNA pool was selected against a complex molecular mixture derived from a breast cancer cell line, T47D. LYF5 specifically indicates the T47D breast cancer cell line with high sensitivity. After sequence optimization, the second-generation DNAzyme, 2G-LYF5, exhibited an approximately 2-fold higher cleavage percentage. Finally, we have determined that the intramolecular stem-loop motif plays a crucial role in 2G-LYF5 activity. Our findings underscore the capability of single-stranded DNA molecules to perform highly sophisticated functions that are amenable to the development of diagnostic tests for early identification of breast cancer.

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