Characterisation of aptamers for therapeutic studies

Abstract

Nucleic acid aptamers, like monoclonal antibodies, bind to their target molecule with high affinity and specificity. Owing to their molecular recognition properties that are based on their three-dimensional structure, aptamers have been used as powerful tools in various fields, such as detection, separation or purification of target molecules. In addition, their intrinsic characteristics make aptamers excellent candidates for therapeutic applications. Due to their high specificity, stability, low toxicity and apparent non-immunogenicity, they provide viable alternatives to antibody- and small molecule-based therapeutics. Unlike antibodies, they can be generated against toxic, unstable or difficult to purify proteins. Furthermore, they can be chemically derivatised to extend their bioavailability and lifetimes in biological fluids, and they even offer the possibility for fast and efficient regulation. Similar to other therapeutic nucleic acids, such as antisense oligonucleotides, ribozymes or siRNA, problems with cellular uptake and susceptibility to nucleolytic attack have to be overcome for their successful application. With the first aptamer-based drug having entered the market and a few in Phase II trials, the road has been paved for more to follow. In this review, the requirements and properties of therapeutic aptamers are discussed and the recent progress in aptamer research towards drug development is highlighted.

RNA aptamer against a cancer stem cell marker epithelial cell adhesion molecule

“…The K’d of all three versions of our aptamer (55–211 nM) are in good agreement with previously reported aptamers against other targets, such as the RNA aptamers to tenascin‐C (5 nM), Trypanosoma cruzi (172 nM), and prostate‐specific membrane antigen aptamer (2–11 nM). ( 38 )…”

“…The K'd of all three versions of our aptamer (55-211 nM) are in good agreement with previously reported aptamers against other targets, such as the RNA aptamers to tenascin-C (5 nM), Trypanosoma cruzi (172 nM), and prostatespecific membrane antigen aptamer (2-11 nM). (38) One of the interesting features of our aptamer is that it is able to bind to human cancer cells expressing a high level as well as a low-medium level of EpCAM. For example, DY647-EpDT3 binds to both gastric carcinoma Kato III cells, which have 893 100 EpCAM protein molecules per cell, and breast carcinoma MDA-MB-231 cells, which have 1700 EpCAM protein molecules per cell (30) (Fig.…”

Thermophoresis in Nanoliter Droplets to Quantify Aptamer Binding

“…[9,10] Just like antibodies, aptamers show high specificity and affinity. At the same time, these nucleic acid based ligands are superior to protein based ligands in production costs, storage conditions, and chemical modifiability.…”

“…At the same time, these nucleic acid based ligands are superior to protein based ligands in production costs, storage conditions, and chemical modifiability. [10] In vivo, their small size facilitates good delivery to the target tissue, Figure 1. A) Droplet production.…”

“…[10,11] These benefits and the first marketed aptamer drug demonstrate the high potential of aptamers. [12] Aptamer binding studies were miniaturized employing a non-contact liquid handling system available commercially (Labcyte).…”