cientists have discovered pieces of DNA which “behave like Bond villains” by helping cancers to spread.
Researchers based in a number of UK and US universities found that extrachromosomal DNA, known as ecDNA, can help tumours to develop resistance to anti-cancer drugs.
ecDNA is present in around a third of cancers, according to Queen Mary’s University.
Professor Paul Mischel, of Stanford University, told The Guardian that the discovery was a potential “game changer” for future cancer treatment.
“We believe they are responsible for a large number of the more advanced, most serious cancers affecting people today. If we can block their activities, we can block the spread of these cancers.”
ecDNA are small, circular pieces of genetic information that enable cancer cells to rapidly evolve to become resistant to treatment.
They can separate themselves from chromosomes and then begin to behave “in ways that circumvent the normal rules of genetics,” according to Stanford geneticist Howard Chang.
He told the newspaper: “They behave like villains in a Bond film. At first, in a film, you see different explosions, killings and disasters occurring and you don’t know why they are happening or who is responsible. Then, at some point, you finally meet the villain who is revealed to be the agent of all this mayhem.”
Pieces of ecDNA often contain oncogenes, which have the potential to cause cancer and are targeted by drugs and therapies.
Prof Mischel explained that, in the most aggressive forms of cancer, the oncogenes were “actually on extrachromosal DNA”.
“The vulnerable gene had quickly disappeared when threatened by cancer drugs and was hidden in ecDNA. Then it reappeared once it was safe for it to start causing damage again,” he said.
The breakthrough comes as part of Cancer Grand Challenges, a global funding platform that supports research teams with funding to develop new ways of tackling cancer. It is funded by Cancer Research UK and the National Cancer Institute in the US.
The ecDNA research involved a team of scientists based in California, London and other centres.
Prof Chang said he hoped that researchers would be able to “pinpoint the achilles heel” of ecDNA and that they had identified a protein that helps to hold it together.
