A class of drug currently being used to treat leukaemia has the unexpected side-effect of boosting immune responses against many different cancers, reports a new BBSRC-funded study led by scientists at UCL and the Babraham Institute, Cambridge.
The drugs, called p110δ inhibitors, have shown such remarkable efficacy against certain leukaemias in recent clinical trials that patients on the placebo were switched to the real drug. Until now, however, they have not been tested in other types of cancer.
The new study, published in Nature, provides the first evidence that such drugs can significantly restrict tumour growth and spread and reduce the chances of relapse for a broad range of cancers. The researchers at UCL, the Babraham Institute, a BBSRC strategically-funded Institute, and Queen Mary University of London, together with scientists from Genentech, South San Francisco, showed that inhibition of the p110δ enzyme helps to boost the body's immune system to kill tumour cells. The research was funded by BBSRC, Cancer Research UK and the Wellcome Trust.
"Our study shows that p110δ inhibitors have the potential to offer effective immunity to many types of cancer by unleashing the body's own immune response," said study co-leader Professor Bart Vanhaesebroeck of the UCL Cancer Institute, who first discovered the p110δ enzyme in 1997. "p110δ is highly expressed and important in white blood cells, called 'leukocytes'. Given that leukaemias are the result of leukocytes becoming cancerous, they are a natural target for p110δ inhibitors. Now, we have shown that blocking p110δ also has the remarkable effect of boosting the body's immune response against leukaemias as well as other cancers."
The team showed that inhibiting p110δ in mice significantly increased cancer survival rates across a broad range of tumour types, both solid and haematological cancers. For example, mice in which p110δ was blocked survived breast cancer for almost twice as long as mice with active p110δ. Their cancers also spread significantly less, with far fewer and smaller tumours developing. Survival after surgical removal of primary breast cancer tumours was also vastly improved, which has important clinical implications for stopping breast cancer from returning following surgery. The team's data further show that following p110δ inhibition, the immune system could develop an effective memory response to completely fight off the cancer.
Lead author Dr Khaled Ali, who is now based at Amgen, San Francisco, said: "When we first introduced tumours in p110δ-deficient mice, we expected them to grow faster because p110δ is important for the immune system. Instead, some tumours started shrinking. When we investigated this unexpected effect, we found that p110δ is especially important in so-called regulatory T cells which are suppressive immune cells that the tumours engage to protect themselves against immune attack."
The p110δ enzyme is a member of the PI3-kinase family, and is sometimes called PI3Kδ. p110δ and the other PI3Ks are hot drug targets for the pharmaceutical industry as they are implicated in many cancers and are readily druggable.
"Our work shows that p110δ inhibitors can shift the balance from the cancer becoming immune to our body's defences towards the body becoming immune to the cancer, by disabling regulatory T cells," said study co-leader Dr Klaus Okkenhaug of the Babraham Institute. "This provides a rationale for using these drugs against both solid and blood cancers, possibly alongside cancer vaccines, cell therapies and other treatments that further promote tumour-specific immune responses."
Professor Nic Jones, Cancer Research UK's chief scientist and director of the Manchester Cancer Research Centre, said: "Treatments that train the immune system to recognise and kill cancer cells are showing huge promise in several types of cancer. This new finding, although only at an early stage, offers the potential to develop more treatments that can do this in many more cancers, including ones that have real need for more effective treatments such as pancreatic cancer.
"If the findings hold true in cancer patients this could make a big difference to many of them. The good news is that because the drugs used in this study are already being used in the clinic, we could see rapid translation of this research into patient benefit."
Notes to editors
For a copy of the paper, or to speak to Professor Vanhaesebroeck, please contact Harry Dayantis in the UCL press office, tel: +44 (0)20 3108 3844, email: firstname.lastname@example.org
To speak to Dr Okkenhaug, please contact Linden Smith, Knowledge Exchange Manager at the Babraham Institute, tel: +44 (0)1223 496260 email: email@example.com
Ali et al, 'Inactivation of the PI3K p110δ breaks regulatory T cell-mediated immune tolerance to cancer', was published in Nature,11 June 2014 6pm and is available at dx.doi.org/10.1038/nature13444.
About UCL (University College London)
Founded in 1826, UCL was the first English university established after Oxford and Cambridge, the first to admit students regardless of race, class, religion or gender and the first to provide systematic teaching of law, architecture and medicine.
Among the world's top universities, as reflected by performance in a range of international rankings and tables. According to the Thomson Scientific Citation Index, UCL is the second most highly cited European university and the fifteenth most highly cited in the world.
UCL has nearly 25,000 students from 150 countries and more than 9,000 employees, of whom one third are from outside the UK. The university is based in Bloomsbury in the heart of London, but also has two international campuses - UCL Australia and UCL Qatar. Annual income is more than £900M. For more information visit www.ucl.ac.uk.
About the Babraham Institute
The Babraham Institute, which receives strategic funding (￡23.1M from 2012-2013) from the Biotechnology and Biological Sciences Research Council (BBSRC), undertakes international quality life sciences research to generate new knowledge of biological mechanisms underpinning ageing, development and the maintenance of health. The Institute's research provides greater understanding of the biological events that underlie the normal functions of cells and the implication of failure or abnormalities in these processes. Research focuses on signalling and genome regulation, particularly the interplay between the two and how epigenetic signals can influence important physiological adaptations during the lifespan of an organism. By determining how the body reacts to dietary and environmental stimuli and manages microbial and viral interactions, we aim to improve wellbeing and healthier ageing. For more information visit www.babraham.ac.uk.
About Cancer Research UK
- Cancer Research UK is the world's leading cancer charity dedicated to saving lives through research
- Cancer Research UK's pioneering work into the prevention, diagnosis and treatment of cancer has helped save millions of lives
- Cancer Research UK receives no government funding for its life-saving research. Every step it makes towards beating cancer relies on every pound donated
- Cancer Research UK has been at the heart of the progress that has already seen survival rates in the UK double in the last forty years
- Cancer Research UK supports research into all aspects of cancer through the work of over 4,000 scientists, doctors and nurses
- Together with its partners and supporters, Cancer Research UK's vision is to bring forward the day when all cancers are cured
For further information about Cancer Research UK's work or to find out how to support the charity, please call 0300 123 1022 or visit www.cancerresearchuk.org.