Scientists improve DNA technology for detecting, treating disease

one of the drawbacks of DNA aptamers - synthetic small molecules that show promise for detecting and treating cancer and other diseases - is they do not bind readily to their targets and are easily digested by enzymes in the body. Now, scientists have found a way to produce DNA aptamers without these disadvantages.

The team - from the Institute of Bioengineering and Nanotechnology (IBN) at Agency for Science, Technology and Research (A*STAR) in Singapore - describes how they developed and tested the improved DNA technology in the journal Scientific Reports.

IBN Executive Director Prof. Jackie Y. Ying says the team created "a DNA aptamer with strong binding ability and stability with superior efficacy," and:

"We hope to use our DNA aptamers as the platform technology for diagnostics and new drug development."

Aptamers are a special class of synthetic ribonucleic acid (RNA) or deoxyribonucleic acid (DNA) molecules that are showing promise for clinical use.

These small molecules could be ideal for drug applications because they can be made for highly specific targets - such as proteins, viruses, bacteria and cells.

Drawbacks of current DNA aptamers

Once aptamers are engineered for a specific target, they bind to it and block its activity.

They are the chemical equivalent of antibodies, except, unlike the antibodies currently used in drug development, they do not cause undesirable immune responses and could be easier to mass produce at high quality.

The first aptamer-based drug - an RNA aptamer for the treatment of age-related macular degeneration (AMD) - was approved in the US in 2004, and several other aptamers are currently being evaluated in clinical trials.

However, no DNA aptamer has yet been approved for clinical use because the ones currently developed do not bind well to molecular targets and are easily digested in the bloodstream by enzymes called nucleases.

In their paper, lead author Dr. Ichiro Hirao, a principal research scientist at IBN, and colleagues describe how they overcame these two problems.