Generating Aptamers for Recognition of Virus-Infected Cells

Abstract

Background The development of molecular probes capable of recognizing virus-infected cells is essential to meet the serious clinical, therapeutic, and national-security challenges confronting virology today. We report the development of DNA aptamers as probes for the selective targeting of virus-infected living cells. Methods To create aptamer probes capable of recognizing virus-infected cells, we used cell-SELEX (systematic evolution of ligands via exponential enrichment), which uses intact infected live cells as targets for aptamer selection. In this study, vaccinia virus– infected and –uninfected lung cancer A549 cells were chosen to develop our model probes. Results A panel of aptamers has been evolved by means of the infected cell–SELEX procedure. The results demonstrate that the aptamers bind selectively to vaccinia virus–infected A549 cells with apparent equilibrium dissociation constants in the nanomolar range. In addition, these aptamers can specifically recognize a variety of target infected cell lines. The aptamers' target is most likely a viral protein located on the cell surface. Conclusions The success of developing a panel of DNA-aptamer probes capable of recognizing virus-infected cells via a whole living cell–SELEX selection strategy may increase our understanding of the molecular signatures of infected cells. Our findings suggest that aptamers can be developed as molecular probes for use as diagnostic and therapeutic reagents and for facilitating drug delivery against infected cells.

Screening and Characterization of a Novel RNA Aptamer That Specifically Binds to Human Prostatic Acid Phosphatase and Human Prostate Cancer Cells

“…In 1990, Szostak's group (Ellington and Szostak, 1990) and Gold's group (Tuerk and Gold, 1990) developed an in vitro aptamer selection process from random sequence pool. Aptamers bind to a wide range of targets, including metal ions (Kawakami et al, 2000), metabolites (Bruno et al, 2008), proteins (Ruckman et al, 1998;Savla et al, 2011), and whole organisms, such as viruses (Tang et al, 2009), bacteria (Hamula et al, 2011) and mammalian cells (Chen et al, 2009). Aptamers have advantages as recognition molecules.…”

Selection and characterization of novel DNA aptamers specifically recognized by Singapore grouper iridovirus-infected fish cells

“…The binding affinity of aptamers was assessed using a protocol described by Tang et al (2009), with some modifications. FITC-labelled aptamers at various concentrations (0-2000 nM) were incubated with SGIV-infected GS cells in the dark for 40 min on ice.…”

Clinical applications of nucleic acid aptamers in cancer

“…The term 'aptamer' means 'to fit' (aptus) in Latin (6), which indicates two important properties of aptamers: i) their ability to fold into complex tertiary structures and recognize their targets with high affinity (low nM to high pM equilibrium dissociation constants); and ii) their specificity, somewhat analogous to antigen-antibody interactions. Using this technique, a number of aptamers that specifically recognize targets, such as metal ions (11)(12)(13), organic dyes and amino acids (14)(15)(16)(17), antibiotics (18,19) and peptides (20,21), as well as proteins of various sizes and functions (6,22,23), whole cells (24)(25)(26)(27), whole organisms (28), viruses (29) and bacteria (30), have been obtained (31)(32)(33). The SELEX process is based on the ability of these small oligonucleotides to fold into unique 3D structures that interact with a target with high specificity and affinity through such interactions as van der Waals surface contacts, hydrogen bonding and base stacking.…”