Reported this month in the online edition of the Journal of Proteome Research, the advance could one day lead to earlier detection and improved treatment of some types of cancer as well as other diseases.
“With many diseases, the problem has been that we really don’t know what to look for,” said Weihong Tan, a professor of chemistry and the lead author of the paper. “What we’ve done is create a technique to identify the biomarkers despite that limitation.”
Doctors often diagnose cancer and other diseases based on the appearance of a tumor or a patient’s symptoms. While such traditional methods can be effective, they sometimes identify a disease only after it is established. For example, clinicians may get tipped off to the presence of lung cancer – which kills more people than any other type of cancer – based on visible images of a tumor that appear on radiological exams of a patient’s lungs.
Because earlier detection typically improves outcomes, doctors would like to spot disease at the molecular level, before it grows or spreads and manifests itself in more obvious and harmful ways. Given that diseased cells’ molecular structures differ from those of healthy ones, that approach should be possible, and researchers have had some success finding such “biomarkers” using antibodies, Tan said. But despite years of research, biomarkers for most diseases remain elusive or unreliable, he said.
His group turned to “aptamers,” single-strand chains of DNA or RNA that recognize and bind to target protein molecules, as a new tool. His paper reports the first-ever successful use of the aptamers to discover a molecular biomarker – in this case, one for leukemia.
Tan said his group used cell-SELEX, a process his group developed and patented.
Researchers create trillions of different varieties of aptamers in a solution. They then immerse cells known to carry the sought-after disease in the solution. After an incubation period, they rinse the cells.
The vast majority of the aptamers wash away, but those with stronger molecular affinity for the diseased cells remain. The researchers repeat the process several times, eventually shrinking the pool of aptamers to as few as 10 to 25 very strongly attached aptamers – those most closely associated with the diseased cells. Analysis then reveals these aptamers’ molecular structure, as well as the molecular structure of the cells’ biomarkers they bind to.
“As long as the molecules in question are expressed in a substantially different way on diseased and normal cells, they can be identified,” Tan said.
Rebecca Sutphen, associate professor and director of the Genetic Counseling & Testing Service at the H. Lee Moffitt Cancer Center & Research Institute in Tampa, said improved diagnosis may not be the only application of the research.
“The opportunity to identify cancer cell-specific biomarkers and potentially detect small numbers of cancer cells has many potential clinical applications, including disease detection, better imaging of tumors and even potential application for stem cells,” she said.
Other biomarkers have been found for leukemia, but none is particularly reliable, Tan said. Tan and his colleagues reported using aptamers to recognize cancer cells in a 2006 paper in the Proceedings of the National Academy of Sciences. Tan said the latest paper advances that work by revealing the target biomarkers the selected aptamers recognize, Tan said. These targets will form a molecular foundation in understanding diseases, he said.
“In 2006, we did not know what the aptamer recognized on the cancer cell surface,” he said. “In this current work, we report discovering these biomarkers, which then form the molecular foundation for us to understand the cancer and to prepare different molecular tools for molecular medicine.”
Tan said the research is particularly promising because aptamers are relatively easy and inexpensive to manufacture compared with antibodies. “This offers the potential for wider application,” he said, adding that aptamers could one day be used not only to detect disease, but also to ferry therapeutic agents to diseased cells.
Weihong Tan | EurekAlert!
Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine
New insight into a central biological dogma on ion transport
26.06.2017 | Aarhus University
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
26.06.2017 | Life Sciences
26.06.2017 | Physics and Astronomy
26.06.2017 | Information Technology