Monday, 24 October 2011
Brain tumour culprit `identified`
Scientists have identified a new biochemical mechanism which they claim allows brain tumours to survive and grow, a finding that may pave the way for new and effective treatments for some of the most aggressive tumours.
An international team, led by the University Hospital of Heidelberg, says that they have identified the key role played by kynurenine, a by-product of metabolism of essential amino acid tryptophan, in favouring the brain tumour growth and at the same time suppressing anti-tumour immune response.
The discovery offers new therapeutic perspectives and gives hope for the treatment of gliomas, the most common and aggressive type of brain tumour in both adults and children, say the scientists.
The team, led by Prof Michael Platten, was also able to identify the receptor expressed by tumour cells that kynurenine acts through -- the aryl hydrocarbon receptor (AhR), the `Nature` journal reported.
While particularly relevant in the development and persistence of gliomas, the kynurenine pathway also has a role in other brain cancers, and is implicated in other neuro- degenerative diseases.
The scientists said the breakthrough could potentially lead to viable therapeutics for a range of conditions, including Alzheime`s disease, motor neuron diseases, multiple sclerosis and Parkinson`s disease.
"We are currently looking at all the molecules deriving from the tryptophan metabolism through the kynurenine pathway that can be linked to tumour persistence and immune suppression," team member Professor Gilles Guillemin said.
An oral drug able to block enzymes leading to kynurenine production has been developed and the drug could potentially be available for clinical trials within a few years, he added.
The survival time for patients with gliomas, particularly the more aggressive tumours such as glioblastoma multiforme, has not changed in decades despite changes in therapeutic approaches. The mechanism elucidated here offers an entirely novel approach to therapy.