Magnetic resonance imaging (MRI) is primarily a medical imaging technique that is used to visualize different soft tissues within the body. In the field of cancer therapy, a contrast agent is often used to help identify the exact location of tumor cells.
As reported in the European Journal of Organic Chemistry, a team led by Carlos Platas-Iglesias and Teresa Rodríguez-Blas from the Universidade da Coruña has recently designed a new set of receptors that may be useful in the design of specific MRI contrast agents for the recognition of certain compounds on the surfaces of tumor cells.
Specific contrast agents that are able to report on their biological environments through molecular recognition processes are highly desired. A specific MRI contrast agent could take advantage of these processes to respond to certain functional groups that can be found in abundance in the diseased tissue. Sialic acid, for instance, is considered to be a tumor marker, because it is known to be over-expressed on the surfaces of tumor cells. An MRI contrast agent specific for sialic acid should bind selectively with the acid in preference to other sugar residues and to saccharides such as glucose and fructose, which occur in relatively high concentrations in the blood.
Platas-Iglesias and Rodríguez-Blas reasoned that a suitable receptor for sialic acid recognition might be based on (thio)urea units containing boronic acid functions, as both of these functionalities show promise as recognition moieties. (Thio)Urea-based receptors can establish strong interactions with anions such as carboxylates, which are present in sialic acids, and boronic acids are able to form reversible complexes with 1,2- and 1,3-diol units present in saccharides.
To test their receptors, the authors monitored their binding to Neu5Ac, which is the most common member of the sialic acid family; it also plays an important role in cellular recognition processes. The receptors were found to bind to Neu5Ac, and importantly, much weaker interaction between the receptors and other saccharides studied was observed. The selectivity was found to occur by cooperative two-site binding of Neu5Ac through (1) interaction at the boronic acid function of the receptor and (2) interaction between the thiourea moiety and the carboxylate group of Neu5Ac. The set of receptors have thus been shown to interact selectively with targets over-expressed on the surface of cancer cells, which makes them promising synthons for the design of specific contrast agents for MRI of tumors.
Author: Carlos Platas-Iglesias, Universidade da Coruña (Spain), mailto:firstname.lastname@example.org
Title: Towards Selective Recognition of Sialic Acid Through Simultaneous Binding to Its cis-Diol and Carboxylate Functions
European Journal of Organic Chemistry, Permalink to the article: http://dx.doi.org/10.1002/ejoc.201000186
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy