A team of researchers led by Fred Hutchinson Cancer Research Center has identified a new mechanism that explains why some recurrent ovarian tumors become resistant to treatment with commonly used platinum-based chemotherapy drugs such as cisplatin and carboplatin. They describe their research online Feb. 10 in the journal Nature.
While these findings are based on the study of ovarian-cancer cells from women with inherited mutations in the BRCA2 gene, they also may help explain the mechanics of cisplatin resistance in ovarian-cancer patients with BRCA1-gene mutations. Together such genetic mistakes are thought to cause about 10 percent of ovarian cancers, according to senior author Toshiyasu (Toshi) Taniguchi, M.D., Ph.D.
“Because BRCA1 and BRCA2 have similar functions in terms of DNA repair, we may be able to generalize these findings for women with either mutation,” said Taniguchi, an assistant member of the Hutchinson Center’s Human Biology and Public Health Sciences divisions.
BRCA2 works to repair damaged DNA; inherited mutations in this gene disrupt that ability, which increases the risk of ovarian and breast cancer. At the same time, such mutations also make cancer cells more vulnerable to DNA-damaging agents such as cisplatin and carboplatin. While ovarian tumors initially respond very well to platinum-based chemotherapy, eventually between 70 percent and 80 percent of advanced-stage ovarian-cancer patients develop a resistance to these drugs.
“The majority of advanced-stage ovarian-cancer patients die due to acquired resistance to platinum-based drugs. It is a serious problem,” he said.
Taniguchi and colleagues at the Hutchinson Center, University of Washington, Cedars-Sinai Medical Center and the Mayo Clinic have uncovered how such resistance occurs. They found that when exposed to cisplatin, some ovarian-cancer cells develop secondary mutations on their BRCA2 gene that restore the gene’s ability to repair DNA. This restoration of gene function then makes the cancer cells resistant to chemotherapy.
“This event is unlike any previous mechanism of resistance to chemotherapy identified in cancers,” said co-author Elizabeth Swisher, M.D., associate professor of medicine in the Department of Obstetrics and Gynecology and director of the Breast and Ovarian Cancer Prevention Program at the University of Washington. “By identifying the cause of chemotherapy resistance in these cancers, we may be able to better predict who will respond to different chemotherapy agents and find novel ways to re-sensitize tumors to chemotherapy that otherwise would not have had a good response to treatment.”
If women with recurrent ovarian cancer are found to have a secondary mutation on their BRCA2 gene, their cancer likely would be resistant not only to platinum-based compounds but also other drugs such as PARP inhibitors. “Testing whether relapsed tumors have a secondary mutation of BRCA2 may be important to predict clinical outcome,” Taniguchi said.
The researchers suspect they may be able to generalize their findings regarding secondary mutations in BRCA2 to other DNA-repair genes, such as BRCA1, which may help explain drug resistance to a variety of cancers, including those of the breast, prostate and pancreas.
Kristen Woodward | EurekAlert!
Researchers simplify tiny structures' construction drip by drip
12.11.2018 | Princeton University, Engineering School
Mandibular movement monitoring may help improve oral sleep apnea devices
06.11.2018 | Elsevier
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
19.11.2018 | Event News
09.11.2018 | Event News
06.11.2018 | Event News
20.11.2018 | Physics and Astronomy
20.11.2018 | Medical Engineering
20.11.2018 | Physics and Astronomy