Autophagy recycling centres inside a cell (blue dots)
This week is Nobel Prize week, the science world’s equivalent to the Oscars.
And the first of the awards to emerge from Stockholm today was the Nobel Prize for Physiology or Medicine. It was given to Japanese scientist Professor Yoshinori Ohsumi for his discovery of the way cells eat themselves, a process that plays a key role in cancer and other diseases.
Like most things in science, the process has a snappy name – autophagy, which literally means ‘self-eating’ (from the Greek words ‘auto’ (self) and ‘phagein’ (eating)).
But why would a cell want to eat itself? And why is this important in cancer?
— Cancer Research UK (@CR_UK) October 3, 2016
The concept of autophagy emerged in the 1960s. But it wasn’t until Ohsumi began studying it in the late 80s that real progress was made.
Ohsumi carried out a series of experiments in the lab using yeast cells to study autophagy. He aimed to find out how the process worked and the role it played inside cells.
His results were groundbreaking.
Not only did he show that the autophagy process does exist in yeast, Ohsumi also discovered how the process is controlled, how it works from start to finish, and the key genes and molecules involved.
On top of this, his work made it possible to study autophagy in human cells.
It’s vital to recycle
Cells are stuffed with lots of different types of molecules packed up in various structures and microscopic machines.
Over time, these molecules and smaller parts can become damaged or worn out by normal wear and tear processes, such as when a cell divides.
When this happens, cells need to get rid of these worn out molecules. And if they don’t, the damaged parts can build up in the cell, becoming toxic and eventually causing the cell to die.
By using this ‘self-eating’ process, cells can break down these worn out bits of themselves and recycle them into something new.
It’s a bit like playing with Lego.
Imagine you’re building a race car because you want to pretend you’re an F1 driver, but then your career aspirations change. If you switch to wanting to be a pilot, you can deconstruct your car and use the same parts to build a helicopter.
Autophagy allows a cell to dismantle its parts and rebuild them in the same way.
Adaption is the key to survival
Getting rid of potentially toxic old rubbish isn’t the only reason cells use autophagy.
The world around a cell can also can change quickly inside the body, and autophagy offers a way to adapt. For example, a cell may suddenly find itself without food or oxygen.
To survive, the cell needs to be able to adapt – and quickly.
This is another reason cells use autophagy.
By deconstructing old parts of themselves they don’t need, cells can turn these parts into something they do need to survive.
So a starving cell can use autophagy to eat bits of itself and get the energy it needs.
It’s like when you don’t eat enough food in the day. Your body isn’t getting the energy it needs, so it breaks down the fat in fat cells and converts it into energy.
Your body breaks down things it doesn’t need (fat) and converts it into something it does need (energy).
So how can this go wrong in cancer?
The link between ‘self-eating’ and disease
Since the pioneering work of Ohsumi, scientists have learned more and more about autophagy.
In particular, they’ve learned more about its role in disease.
Among others, faults in autophagy have been linked to diabetes, Parkinson’s disease and cancer.
Cancer cells are constantly adapting to survive and keep growing.
And in recent years it’s been shown that autophagy plays a key role in how cancer cells do this – and how they use it to resist treatment.
For example, by working with mice and human cells, researchers in Glasgow have shown that treating chronic myeloid leukaemia cells with a combination of a targeted drug and one that blocks autophagy kills more cancer cells than the targeted drug alone.
Dr Noor Gammoh, a Cancer Research UK scientist in Edinburgh, is studying the role of autophagy in glioblastoma, the most common type of brain tumour.
“We know that some types of cancer cells can use the autophagy ‘self-eating’ process to survive and thrive under harsh environments,” she says. “My team wants to know if this is also the case for glioblastoma cells.”
“If we do find that autophagy is important in glioblastoma, we hope to be able to develop new treatments that target the process.
And if this holds true, says Gammoh, it “could help improve survival for this type of brain tumour, where survival remains low”.
This research, and the work of hundreds of other cancer researchers around the world, would not be possible without the ground-breaking discovery of Professor Yoshinori Ohsumi.
So today, when he is receiving arguably the greatest accolade in science, we’d simply like to say congratulations.