Home | News | Diet will in fact complement cancer treatments, but basic research and clinical trials are still lacking

Speakers and audience at the ‘CNIO-CaixaResearch Frontier Meeting Metabolism and Cancer: Insights from Obesity and Beyond’. / Christian Esposito. Madmoviex. CNIO.

“You’re never going to be able to cure cancer with diet alone, that’s not going to happen,” stresses Turkish researcher Kivanç Birsoy of Rockefeller University (USA). Those attending a recent congress at the Spanish National Cancer Research Centre (CNIO), international leaders in this area, agree with him. So, no, there is no such thing as an ‘anti-cancer diet’.

But nutrition undoubtedly has a lot to do with cancer. In recent years, it has become clear that what we eat, and how much we eat, matters. Obesity is associated with an increased risk of developing 13 types of cancer, and with an increased likelihood of metastasis.

What is missing now is an understanding of the details in this hugely complex relationship. What molecular mechanisms do link cancer and obesity? How does each nutrient play a role? What about physical activity? Knowing the answers would allow us to use diet and habits not only to prevent, but also to help treat cancer.

Eileen White: “Giving power back to the patient

Diet could be a powerful add-on: specific nutrients could enhance a particular treatment or reduce its side effects. Or, if we understand why a certain hard-to-follow diet has benefits, a drug could be designed to copy its effect.

Eileen White, of the Rutgers Cancer Institute (USA), calls this “giving power back to the patient”. People with cancer would participate in their own treatment with medically ‘prescribed’ habits.

The good news is that genomics, proteomics and metabolomics – as well as computation and AI to extract the relevant information from the big data generated by all these technologies – make it possible to investigate the relationship between nutrition and cancer as never before.

Birsoy: “What diet for what cancer? We will know in 10 years”.

Birsoy says that early in his career, “I realised that if we figured out what nutrients cancer cells need, and how they get them, we might be able to cut off their supply.”

His group looks at the dependence of cancer on specific amino acids and lipids. They have recently discovered  that, under certain conditions, some antioxidants that act within cellular compartments may promote cancer. In particular, glutathione helps cancer cells to metastasise, because it allows them to survive in oxygen-poor conditions.

But this area of research is still in its infancy and has not yet reached patients, says Birsoy. We need “five to 10 years before diet can complement cancer treatment, but we’ll get there,” he states. “We already have the technology to learn how to connect the genetics of individual patients to specific nutrients and types of cancer. But we need more basic research, like the kind done at centres such as CNIO, and clinical trials.”

Metabolism: cancer talks to the rest of the body

Nutrients are only part of the story. Investigating the role of obesity, the immune system, nutrition and exercise in cancer involves investigating metabolism, the biochemical reactions that occur in cells to convert nutrients into energy.

Researchers have known for decades that metabolism is disrupted in a body affected by cancer. Tumour cells need more energy because they proliferate faster, which is why tumours are visualised by detecting tissues with high sugar consumption, as in the PET scan. Furthermore, cancer reprogrammes its metabolism to extract nutrients via unusual biochemical pathways, enabling it to survive even with limited resources.

But, once again, gaining a deeper understanding of metabolism was… a complex task without the right technology. More than 5,000 of the approximately 22,000 genes in the human genome are involved in metabolism; the metabolic pathway diagrams of an organism are a veritable jungle. Now, the 150 participants at the CNIO congress are celebrating that the time has come.

Efeyan: “Diet, exercise… these are now a focus of research, whereas they weren’t before.”

For Alejo Efeyan, CNIO researcher and co-organiser of this event, this is “changing the focus of research. We have realised that cancer cells are not isolated, they actively interact with the body. So there is now a lot of activity in areas that were not paid much attention before: diet, metabolism, exercise and basically all the points of connection between the cancer cell and the rest of the body.

Learning to control how the tumour talks to the body could expand the effectiveness of immunotherapy, for example: “The immunotherapy revolution is based on the cancer’s conversation with the immune system; there are other conversations going on and, if we explore them, we can find other ways to attack the cancer cell,” Efeyan adds.

Djouder: “Obesity increases risk, but there are healthy obese people, we need to understand why.”

Nabil Djouder, CNIO researcher and co-organiser of this event, shone a spotlight on obesity, whose relationship with cancer and other diseases is increasingly clear but still misunderstood. To begin with, “not all people with obesity have a higher risk of cancer; there are people with a high body mass index who do not have the pathologies associated with obesity. We need to understand this properly,” says Djouder.

In a recent review on the use of diet in cancer treatments, Djouder explained that “diets can directly target cancer metabolism by depriving the tumour of the nutrients it needs (…)”. At the conference, he presented one of his latest findings on how a deficiency in a particular protein contributes to the development of liver fibrosis, a crucial step in the progression towards cirrhosis and liver cancer.

Sabio: “It’s not just the amount you eat, it’s also the quality”.

Body weight is not the only thing that counts; similarly, the key is not just the amount you eat. “Quality is very important, not all fats are the same,” says Guadalupe Sabio, also a CNIO researcher and co-organiser of this event. 

Sabio is coordinating a major European project to unravel how fat communicates with the rest of our body and thus influences health. She stresses that “not all fats have the same effect. We know from epidemiological studies that the impact of obesity on health is different in people of the same weight but on different diets.”

Her research has helped to clarify that adipose tissue – that ‘spare tyre’ – is not just a fat store; it is also an endocrine and inflammatory organ that influences the behaviour of tumour cells and the immune system,” explains Sabio. “Our studies could help identify risk biomarkers and preventive strategies in patients with obesity.”

More personalised clinical trials

More clinical trials are needed to bring discoveries in this area to oncology practices. Rigorously studying the effect of a diet is difficult, because of the many elements involved: many people have to be monitored in terms of eating the right foods, and little is known about the interaction of each nutrient with others and with the individual’s genetics.

This is why many studies seem to come to contradictory conclusions, warns Birsoy: “Some say this nutrient is good for that cancer, others say it’s not… It’s preliminary. The main problem is that we don’t know which tumours to tackle with which nutrients. And when trials are done, the right patient populations are still not selected. We still have so much to learn. That’s why we need basic science.”

Miguel Ángel Quintela, head of the CNIO Breast Cancer Clinical Research Unit and co-organiser of the conference, leads one of the pioneering trials in personalised research into the relationship between nutrients and cancer. It targets women with breast or gynaecological tumours who are being treated with a state-of-the-art therapy that administers small doses of concentrated chemotherapy. The LUMINOVA trial began recently at Hospital 12 de Octubre.

The CNIO-CaixaResearch Frontiers Meetings are highly prestigious international conferences on cutting-edge aspects of cancer research. At these events, twenty guest speakers from around the world present their most recent findings. A further hundred experts, selected for the significance of their contributions, also participate through poster presentations or short talks.

Organising Committee of the ‘CNIO-CaixaResearch Frontier Meeting Metabolism and Cancer: Insights from Obesity and Beyond’.

Representing CNIO: Nabil Djouder, from the Growth Factors, Nutrients and Cancer Group; Alejo Efeyan, from the Metabolism and Cell Signalling Group; Guadalupe Sabio, from the  Metabolic Interactions Group; and Miguel Quintela, director of the CNIO Clinical Research Programme.

As well as: Roger Davis, from UMass Chan Medical School in Massachusetts, USA; and Mª Carmen Fernández Agüera, Cell Metabolism, Cell Press, Seville.

Programme: https://apps.cnio.es/eventos/descargas/CFM/08052392_289,52_pdf3.pdf

About the National Cancer Research Centre (CNIO)

The National Cancer Research Centre (CNIO) is a public research centre under the Department of Science, Innovation and Universities. It is the largest cancer research centre in Spain and one of the most important in Europe. It includes around five hundred scientists, along with support staff, who are working to improve the prevention, diagnosis and treatment of cancer.

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