Bowel cancer cells can stimulate blood vessel growth
Scientists say they may be able to turn off a "system" that helps bowel tumours survive and grow bigger.
The University of Bristol team says it has found how a cancer detects the need for more blood vessels to supply it with the oxygen it needs to grow.
It may be possible to "switch off" this detection system and kill off tumours, the researchers say.
Their work, published in the journal Nature Cell Biology, could help improve drugs to fight these cancers.
Bowel cancer is the second biggest cancer killer in the UK, with approximately 17,000 people dying from the disease every year - about half of those diagnosed.
Experts need to find differences between the make-up of cancer cells and normal cells in order to discover ways to kill one, without harming the other.
One of the most important differences in bowel cancers are the tactics employed by the cell to survive past the point an ordinary cell would normally die.
Bowel cancer cells produce a chemical which bypasses this "cell suicide" and stimulates uncontrolled growth, eventually forming a cluster of cancer cells called a tumour.
This cell cluster eventually needs an improved blood supply in order to be able to carry on growing - if it cannot get extra blood, the cells will starve to death.
Sending for blood
The Bristol team found that the tumour can sense when this is about to happen, and at that point, the chemical that triggers its growth changes role, and helps form a chemical messenger which instructs the body to create new blood vessels around the tumour.
This process is called angiogenesis, and doctors have already created drugs - such as Avastin - designed to interfere with this.
However, the new research, which looks at the process in more detail, could help create more precisely targeted drugs, which can turn off angiogenesis without some of the side-effects risked by those taking the current generation of chemotherapy.
Professor Chris Paraskeva, who led the research, explained: "We believe it is essential to understand the survival strategies of cancers as they grow, and how they develop resistance to treatment therapies.
"These cancers are incredibly smart and constantly adapt to their environment in order to survive - we have just got to be smarter.
"We hope to use this new information to try and interfere with the tumour's survival tactics and thereby kill it off."
Dr Rob Glynne-Jones, a clinical oncologist at Mount Vernon Hospital in London, and a scientific adviser to the charity Bowel Cancer UK, said the project had produced "interesting" results.
He said: "This is another step forward towards more specific drug treatments which do not carry as high a risk of side-effects in some patients.
"I have no doubt that in the future drugs will be produced which will turn cancer into a long-term chronic illness, managed by the patient over far longer periods."
This research was funded by Cancer Research UK. Its medical director, Professor John Toy, said: "Bowel cancer is one of the most common cancers in Britain, so research aimed at reducing this toll is vitally important.
"This discovery adds to our understanding of how bowel cancer cells survive when their oxygen and food supplies become severely reduced, and could lead to new cancer treatments.
"We look forward to seeing the team's research progress in further laboratory studies and hope eventually to see it translate to clinical trials in patients."