An anti-cancer drug used extensively in chemotherapy binds pervasively to RNA -- up to 20-fold more than it does to DNA, a surprise finding that suggests new targeting approaches might be useful, according to University of Oregon researchers.
Medical researchers have long known that cisplatin, a platinum compound used to fight tumors in nearly 70 percent of all human cancers, attaches to DNA. Its attachment to RNA had been assumed to be a fleeting thing, says UO chemist Victoria J. DeRose, who decided to take a closer look due to recent discoveries of critical RNA-based cell processes.
"We're looking at RNA as a new drug target," she said. "We think this is an important discovery because we know that RNA is very different in tumors than it is in regular healthy cells. We thought that the platinum would bind to RNA, but that the RNA would just degrade and the platinum would be shunted out of the cell. In fact, we found that the platinum was retained on the RNA and also bound quickly, being found on the RNA as fast as one hour after treatment."
The National Institutes of Health-supported research is detailed in a paper placed online ahead of regular publication in ACS Chemical Biology, a journal of the American Chemical Society. Co-authors with DeRose, a member of the UO chemistry department and Institute of Molecular Biology, were UO doctoral students Alethia A. Hostetter and Maire F. Osborn.
The researchers applied cisplatin to rapidly dividing and RNA-rich yeast cells (Saccharomyces cerevisiae, a much-used eukaryotic model organism in biology). They then extracted the DNA and RNA from the treated cells and studied the density of platinum per nucleotide with mass spectrometry. Specific locations of the metal ions were further hunted down with detailed sequencing methods. They found that the platinum was two to three times denser on DNA but that there was a much higher whole-cell concentration on RNA. Moreover, the drug bound like glue to specific sections of RNA.
DeRose is now pursuing the ramifications of the findings. "Can this drug be made to be more or less reactive to specific RNAs?" she said. "Might we be able to go after these new targets and thereby reduce the drug's toxicity?"
While cisplatin is effective in reducing tumor size, its use often is halted because of toxicity issues, including renal insufficiency, tinnitus, anemia, gastrointestinal problems and nerve damage.
The extensive roles of RNA have come under intense scrutiny since completion of the human genome opened new windows on DNA, life's building blocks. It had been assumed that RNA was simply a messenger that coded for protein activity. New technologies, DeRose said, have shown that a vast amount of RNA performs an amazing level of different functions in gene expression, controlling it in specific ways during development or disease, particularly in cancer cells.
In this project, DeRose's team only explored cisplatin's binding on two forms of RNA: ribosomes, where the highest concentration of the drug was found; and messenger RNA. There are more areas to be looked at, said DeRose, whose group initially developed experience using and mapping platinum's activity as a mimic for other metals in her research on RNA enzymes.
DeRose is now planning work with UO colleague Hui Zong, a biologist studying how cancer emerges, to extend the research into mouse cells to see if the findings in yeast RNA hold up. An additional collaboration with UO chemist Michael Haley involves the creation of new platinum-based drugs with "reaction handles" that will allow researchers to easily pull the experimental drugs out of cells, while still attached to their biological targets. New developments in 'deep' RNA sequencing, available through the UO's Genomic Core Facilities, could then provide a much broader view of platinum's preferred resting sites in the cell.
About the University of Oregon
The University of Oregon is among the 108 institutions chosen from 4,633 U.S. universities for top-tier designation of "Very High Research Activity" in the 2010 Carnegie Classification of Institutions of Higher Education. The UO also is one of two Pacific Northwest members of the Association of American Universities.
Source: Victoria DeRose, professor of chemistry, 541-346-3568, firstname.lastname@example.org
Links:DeRose chemistry faculty page:
Jim Barlow | EurekAlert!
New application for acoustics helps estimate marine life populations
16.01.2018 | University of California - San Diego
Unexpected environmental source of methane discovered
16.01.2018 | University of Washington Health Sciences/UW Medicine
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
17.01.2018 | Ecology, The Environment and Conservation
17.01.2018 | Physics and Astronomy
17.01.2018 | Awards Funding