'CANNABIS' BRAIN TUMOUR DRUG HOPE

An ingredient in marijuana may be useful for treating brain cancers, say
Spanish researchers from Madrid.

Chemicals called cannabinoids could starve tumours to death by halting the
growth of blood vessels that feed it, the Complutense University team hope.

By studying mice, the team has shown for the first time how these chemicals
block vessel growth.

Their study, published in Cancer Research, also shows the treatment appears
to work in humans.

Glioblastoma multiforme is the most common brain cancer and is notoriously
difficult to treat.

It can evade destruction by radiotherapy, chemotherapy and surgery.

Dr Manuel Guzman and colleagues set out to determine whether they could
prevent the cancer from growing by destroying its blood supply.

Previous research has shown cannabinoids block the growth of blood vessels
in mice, but little is known about how these chemicals do this and whether
they might do the same in human tumours.

Starving tumours

The researchers first gave mice cancer resembling the human form of brain
cancer they wanted to study.

They then treated the mice with cannabinoid and examined the genes of the mice.

The activity of genes associated with blood vessel growth in tumours
through the production of a substance called vascular endothelial growth
factor (VEGF) was reduced.

Cannabinoids appeared to stifle VEGF production by increasing the activity
of a substance that controls cell death, called ceramide.

Lead researcher Dr Guzman said: "As far as we know, this is the first
report showing that ceramide depresses VEGF pathway by interfering with
VEGF production."

Their next challenge was to see if cannabinoids had the same effect in humans.

They took samples from two patients with glioblastoma multiforme who had
not responded to surgery, chemotherapy and radiotherapy treatment.

Treatment for humans

Samples were taken before and after the patients were treated with
cannabinoid solution infused directly into the tumour.

In both patients, VEGF levels in the tumour were reduced following
treatment with cannabinoids.

Although they only looked at two patients, the researchers hope their
findings could lead to new treatments.

"The present findings provide a novel pharmacological target for
cannabinoid-based therapies," said Dr Guzman.

Dr Richard Sullivan, Head of Clinical Programmes at Cancer Research UK,
said: "This research provides an important new lead compound for
anti-cancer drugs targeting cancer's blood supply.

"Although this work is at an early stage of development, other research has
already demonstrated that VEGF is an important drug target for a range of
cancers.

"The key now will be to show further activity in pre-clinical cancer
models, find out in which combinations cannabinoids show greatest activity
and formulate a product that can be tested in man.

"It is important to note that cannabinoids would need to generate very
strong data in the future as there are already a number of VEGF inhibitors
in clinical development," he said.