Gene therapy boosts immune system against cancer
Transfusions of genetically engineered blood cells could give bowel cancer patients a powerful boost against their disease, scientists from Cancer Research UK report.
The technique involves engineering patients' white blood cells - the foot soldiers of the immune system - to recognise and destroy tumours. Scientists now intend to begin the UK's first trial of the treatment, which they hope will transform the prospects of many people with bowel cancer.
For the immune system to successfully fight off cancer, it first has to recognise cancer cells as alien invaders, just as it does with bacteria or viruses. But unlike infectious agents, cancer cells are rogue versions of the patient's own cells and carry a very similar set of genes, making them much harder to recognise and attack.
In the new study, researchers from the Cancer Research UK Department of Medical Oncology at the Paterson Institute for Cancer Research in Manchester aimed to give white blood cells an artificial boost to help them fight off the disease.
They took blood samples from 10 patients with advanced bowel cancer and isolated a type of white blood cell called T-lymphocytes, which are responsible for homing in on alien cells and attacking them. Researchers engineered the lymphocytes with an artificial gene. They created this by fusing a homing element, for recognising bowel cancer cells, and an activating element, causing lymphocytes to attack and kill their targets.
Researchers tested these engineered lymphocytes in the laboratory for their ability to kill bowel cancer cells. Engineered cells from all 10 patients in the study showed powerful anti-cancer activity; the fusion gene was directing them specifically and potently against cancer.
Professor Robert Hawkins of the Cancer Research UK Department of Medical Oncology at the Paterson Institute says: "In most situations, the immune system is powerful and highly effective, but when it comes to cancer it can get confused and may need a helping hand.
"What we've done in this new study is give our immune cells the equipment they need to recognise, home in on and destroy cells from tumours, allowing us to harness the power of the immune system to tackle the disease.
"We've shown that the technique works a hundred per cent of the time in the laboratory, but the real test will be whether it works in cancer patients, which we'll begin to look at in the clinical trial."
The trial of the technique will take place next year at Manchester's Christie Hospital.
News of the research comes at the beginning of bowel cancer awareness month (April), which will highlight the need for better treatment of the disease, the second biggest killer cancer.
Professor Robert Souhami, Cancer Research UK's Director of Clinical Research, says: "If detected early bowel cancer is usually treatable, but once it has started spreading round the body the chances of recovery become increasingly slim.
"There's still a long way to go in the development of this new technique, but it does seem to hold promise for the treatment of cases which are out of reach of conventional medicine."
- British Journal of Cancer88 (7)
Notes to Editor:
The homing element is part of a gene for an antibody specific for carcinoembryonic antigen - a molecule that commonly occurs in bowel cancer cells.
The activating element is a section of DNA coding for the TCR CD3 zeta chain. This gives the T-lymphocytes potent cell-killing activity.
Bowel cancer is the third most common cancer, with 35,550 cases each year. It is the second biggest killer, with over 16,000 deaths annually.