GM blood kills human cancer cells

18:29 01 April 03 NewScientist.com news service
Genetically modifying a patient's white blood cells turns them into potent
cancer killers, UK researchers have revealed.

The team modified T-cells - the immune system's first line of defence - enabling
them hunt out and destroy cancer cells in test tube experiments. Both the cell
types were taken from patients with advanced bowel cancer.

The technique had destroyed the cancer cells in every experiment so far, says
team member Robert Hawkins, a medical oncologist at Cancer Research UK's
Paterson Institute in Manchester Hawkins.

The effectiveness of the new treatment will next be assessed in about 30
advanced bowel cancer patients, starting next year. White blood cells will be
taken from the patients, genetically modified, and then transfused back into the
patients.

Bowel cancer is estimated to affect 300,000 people in Europe and the US each
year. It is the second biggest cancer killer in the UK with over 16,000 deaths a
year.


Rogue version


The body's immune system effectively fights off many diseases because it
recognises the bacteria or viruses that cause them as foreign. However, because
cancerous cells are rogue versions of a patient's own cells, the body fails to
recognise them as dangerous.

"What we've done 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," says Hawkins.

Robert Souhami, Cancer Research UK's director of clinical research, adds:
"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."


Punching holes





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Weblinks


Cancer Research UK

Colon Cancer Concern, UK

T-cells and lymphokines, ImmuneCentral

British Journal of Cancer



Hawkins and colleagues took blood samples from 10 patients with advanced bowel
cancer and isolated their T-lymphocyte cells. They then genetically modified
these cells to carry a gene that produces an antibody that recognises a specific
molecule on the surface of bowel cancer cells.

This antibody allows the T-cell to bind onto the cancer cell and trigger a chain
of events that turns the T-cells into "killer cells". The killer cells destroy
the cancer cells by releasing a molecule called perforin that punches holes in
the cancer cells' walls. They also release chemical messengers called cytokines,
which call in other immune cells to attack the cancer cells.

Hawkins said the technique also helped fight the cancer by multiplying the
patients' white blood cells. "We would take maybe 10 million cells, expand them
to 10 billion cells, and then return them to the patient," he told New
Scientist.

Journal reference: British Journal of Cancer (DOI: 10.1038/sj.bjc.6600857-02th)


Shaoni Bhattacharya


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