Dr Lee Parry

"There are many arguments about cancer stem cells and whether they truly exist and whether any cell can be a cancer stem cell. But for the purposes of my research, it's just a cell with properties which propagate the cancer."

Who are you?

I grew up in the Rhondda Valleys, so fairly local. I came to Cardiff to do my undergrad, and stayed to do my PhD in cancer genetics, specifically tuberous sclerosis which is a cancer syndrome. After that, I moved to Melbourne but returned to Cardiff nine years ago. I returned and took up a postdoc with Alan Clarke on bowel cancer. I learnt about cancer stem cells, intestinal stem cells and epigenetic regulation and from there I got interested in how you can regulate your stem cells and the influence your diet and gut bacteria play in how you can approach treating cancer.

What is your definition of cancer stem cells?

For the purposes of my research, it's a cell with properties that propagates and supports the cancer. So, much like a normal stem cell, they're the original cells. Rather than trying to prove or disprove them or even understand them, I work under the assumption that cancer stem cells exist.

What research are you carrying out at the Institute?

We all know that eating healthily is good for you, but we don't really know why. So, through funding from the World Cancer Research Fund, I'm looking at taking apart the different components of the diet and observing their effect on cancer.

For example, there's convincing evidence that a high fibre diet helps protect against colorectal cancer. We think this is because fibre acts as a food source for many of the bacteria in your gut; feeding them, causing their numbers to grow and increasing the number of metabolites they produce. One of these metabolites is butyrate, which is the main energy source for the intestinal epithelial cells. So a high fibre diet keeps your epithelial cells healthy and inflammation low, helping prevent cancer.

What we're doing is taking normal stem cells from a mouse and growing those in culture to make mini-guts as well as taking stem cells with cancerous mutations and growing those in culture to make a tumour. We're then co-culturing the mini-guts and the tumours individually with different dietary components, identifying the different metabolites that the bacteria produce and the effect the metabolites have on normal and cancer stem cells, whether it be to divide, grow or die.

Where do you see your research being applied?

On the one hand, you might find a therapeutic benefit; a dietary component that has a real effect on stem cells or cancer stem cells. On the other hand, it provides more evidence for the World Health Organisation for why we should eat healthily. 90% of upper GI cancers are attributable to environmental factors, so it would be great if we could tell someone, 'eat this, because if you eat this, this will happen, and that's why you don't get cancer'.

However it's not that simple. A lot of the diet will be good at preventing cancer but equally once you have cancer, may be a bad thing. For example butyrate will feed cancer cells and metabolites which would normally supress inflammation will then begin to encourage cancer growth. So maybe we need to look at different diets for pre and post cancer diagnosis, and see what environmental changes we can make.

What have you been up to today?

Today was the usual mix of lab work, attending seminars [at the Stem Cell Symposium], training students, organising the research and coffee drinking!

How do you see working within the Institute being an advantage to you?

I'm a local boy, working locally, supporting my own city and the University. And on top of that, the advantages are definitely the collaborators; being able to work with Alan [Clarke] again and having such great support.

(Interview and photograph: Sophie Hopkins, final year Biosciences undergraduate student)