Single protein holds key to stifling spread of cancers
A single protein holds out the promise of new treatments which could stifle the growth and spread of many cancers, say scientists.
The enzyme, known as PI-3 kinase gamma, is believed to play a key role in the process by which inflammation fuels tumours.
Blocking the protein in animal studies led to dramatic reductions in tumour growth, progression and spread.
Scientists believe that the molecule could provide a new therapeutic target for most, if not all, solid tumour cancers.
The discovery builds on increasing evidence that inflammatory action by the immune system can make cancers more aggressive.
US and Italian researchers identified a mechanism whereby myeloid immune cells enter tumours and accelerate their growth and ability to spread around the body.
The spread, or metastasis, of tumours to vital organs is the most common cause of death from cancer.
PI-3 kinase gamma operates like a "switch" that allows myeloid cells to invade tumours.
When its action was blocked, either genetically or through the use of a drug, cancer growth was held back. Scientists also saw a dramatic decrease in metastasis.
Enzyme
The research is being published today in the journal 'Cancer Cell'.
Study leader Professor Judith Varner, from the University of California at San Diego (UCSD), in the US, said: "Most strategies targeting the role of myeloid cells in cancer have focused on reducing their expression of inflammatory molecules.
"We've found a single convergent point -- the PI-3 kinase gamma enzyme -- that, when blocked, appears to result in significant suppression of tumour inflammation and growth regardless of the initiating event. It could be a very important therapeutic target for future cancer treatments and could impact most, if not all, types of solid cancer."
Professor Michael Karin, from UCSD's Laboratory of Gene Regulation and Signal Transduction, said: "I think that the inhibition of PI-3K activity represents a very interesting and promising approach for inhibition of tumour-associated inflammation. It seems to fully normalise the tumour microenvironment and provide a new addition to our armament of anti-cancer drugs."
A number of biotechnology companies are already developing drugs that inhibit PI-3 kinase proteins to treat cancer, heart disease and arthritis.
The PI-3 kinase gamma enzyme might be a particularly promising target because blocking it was not likely to produce many side-effects, said the scientists.
- John von Radowitz
Irish Independent
