Scientists block brain tumour growth
Scientists in Geneva report that they have found a way of killing brain tumour cells that could eventually be applied to other types of incurable cancer.
The researchers at Geneva University Medical School say the results from tests on mice and in vitro are encouraging but caution that human trials have yet to start.
Speaking at a news conference in Geneva on Wednesday, team leader Ariel Ruiz i Altaba said he was "very confident" that a way had been found for stopping glioma, an aggressive form of brain tumour. Patients diagnosed with glioma typically survive for only a year.
Previously the team had established that by using a variety of methods - including use of a naturally occurring chemical called cyclopamine - they could block a molecular pathway that gives rise to a variety of cancers, including brain, skin, prostate, stomach and pancreatic.
What they have now discovered is that direct inhibition of the production of a protein, GLI1, or treatment with cyclopamine also destroys cancer stem cells – responsible for cancer growth and tumours growing back – that are not targeted by most cancer treatments.
"We now have proof of principle for a rational therapy that will attack both the bulk of the tumour as well as its rare cancer stem cells," Ruiz i Altaba, a professor of stem cells, told swissinfo.
"My feeling is this may very well work, with the caveat that nobody knows until it is tried in humans," he added.
Ruiz i Altaba believes the pre-clinical data – published in the latest edition of Current Biology – is both good enough and important enough for the discovery to go to clinical trials, especially as the treatment would be aimed at the terminally ill.
He said the hope was that cancerous stem cells in other tumours that use the same pathway, known as the Sonic Hedgehog-GLI1, could also be inhibited.
"It appears to be a very, very important pathway of cellular communication that is critical for the growth, the survival and probably recurrence of many types of tumour," he said.
"The majority of them are carcinomas [invasive cancers], which are really the main problem. So we're very hopeful that something can be done – at least something that could be used in addition to existing therapies."
According to the Geneva University team, more effective targeting of tumours could lead to lower drug doses and less chemotherapy.
The Swiss Cancer League, which is funding part of the research along with the Louis-Jeantet Foundation and other institutions, said it was encouraged by developments but cautioned that there was still a long way to go.
"It's too early to say whether this will become an efficient therapy in the future, but it's certainly something worth pursuing," said Joachim Lingner, a member of the league's scientific committee and professor at the Swiss Institute for Experimental Cancer Research.
Ruiz i Altaba said additional financial support was now needed to enable further research.
swissinfo, Adam Beaumont in Geneva
Professor Ruiz i Altaba's team is based at Geneva University Medical School's department of genetic medicine and development.
He has been studying the role of the Sonic Hedgehog-GLI1 pathway for over a decade.
In September 2004 in vitro tests proved that cyclopamine could block the pathway which gives rise to certain cancers.
The following year, similar positive results were achieved on mice bred with a form of human brain tumour.
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