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!
Mass spectrometry sheds new light on thallium poisoning cold case
14.12.2018 | University of Maryland
Protein involved in nematode stress response identified
14.12.2018 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
14.12.2018 | Power and Electrical Engineering
14.12.2018 | Physics and Astronomy
14.12.2018 | Physics and Astronomy