Breast cancer cells release protective proteins that can actually suppress tumours, according to new research.
A study suggests one enzyme triggers the immune system to attack the disease, and experts say harnessing this could lead to new treatments.
It is hoped the breakthrough, which turns previous thinking on its head, will lead to drugs, or even diet advice, that can boost production of these ‘good' cells.
Scientists originally believed the production of the enzyme - MMP-8 (matrix metalloproteinase-8) - by breast cancer cells worked to promote tumour growth.
Breast cancer cells release protective proteins that can actually suppress tumours by encouraging the immune system to attack the disease
Biologist Professor Dylan Edwards, of the University of East Anglia, said: ‘MMPs are a family of enzymes that are released from cancer cells.
‘They were once thought to act like “molecular scissors” to snip away at the scaffolding structures outside cells and clear a path for the cancer cells to invade and spread to other organs.
‘Drugs that target this broad family of enzymes were trialled to treat cancer in the 1990s but largely failed. This led us to think not all of these enzymes were bad guys that promoted tumour growth and spread.’
He explained: ‘The problem with the original medications is they took out the “good guys” as well as the "bad guys".
‘Pharmaceutical companies are now working on second and third generation drugs that will be more selective. Another possibility is the development of drugs that boost MMPs, or finding foods that do.
‘There are a number of exciting avenues to explore, including screening breast cancer patients for the number of MMPs their tumours are producing.’
Research published five years ago first revealed MMP-8 holds tumours in check. And patients whose breast cancer has more of the enzyme appeared to have better outcomes.
The finding could lead to the development of a new generation of drugs that work by boosting the 'good' cells
So Professor Edwards’ PhD student Sally Thirkettle, and colleagues, decided to look in detail at the patterns of MMPs in patients’ breast tumours.
He said: ‘She has shown if she makes breast cancer cells produce MMP-8, it causes them to produce two other inflammatory factors that have previously been shown to promote cancer. However, breast tumour cells that over-produce MMP-8 do not survive long term. The enzyme stops them growing.
‘We now think in tumours, MMP-8 acts as a sort of “find me” signal to the immune system, which then becomes activated to attack the tumour, which may help to explain its protective function.’
Professor Edwards added: ‘The fact a protective enzyme such as MMP-8 was also blocked by the first generation anti MMP drugs used in the 1990s also partly explains why these drugs failed in the clinic.’
It is still unknown exactly how MMP-8 causes the inflammatory factors, known as IL-6 and IL-8, to be activated but the findings reported in the Journal of Biological Chemistry are an important step forward which will help direct further research.
Read more: http://www.dailymail.co.uk/health/article-2329686/Breast-cancer-cells-SUPPRESS-tumour-growth-releasing-protective-proteins.html#ixzz2UQ60fefo
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