The findings centre on mitochondria - tiny, specialised sub-units of cells that act as cell "generators" and help them grow and function. Photo / 123RF
The findings centre on mitochondria - tiny, specialised sub-units of cells that act as cell "generators" and help them grow and function. Photo / 123RF
A breakthrough study by Kiwi and Australian scientists has opened the door to a new way to attack cancer.
The findings centre on mitochondria - tiny, specialised sub-units of cells that act as cell "generators" and help them grow and function.
Measuring just a 1000th of a millimetre each, they pass down the maternal line and have their own small set of DNA.
When deprived of mitochondria, the scientists revealed, cancer cells couldn't form new strands of DNA – effectively stopping them from growing and forming tumours.
This suggested that blocking the access of cancer cells to mitochondria could lead to new targets for research, and potentially fresh treatments down the line.
The new findings, just published in the major journal Cell Metabolism, followed on from landmark research in 2015 that showed how cancer cells with damaged mitochondria were able to source replacement mitochondria from surrounding healthy cells to restore their function.
They since discovered that it wasn't just the mitochondria's energy-producing abilities that cancer cells sought out - but something much more unexpected.
"Previously, we thought of mitochondria solely as energy powerhouses," explained study co-author Professor Mike Berridge, the head of the cancer cell biology programme at the Wellington-based Malaghan Institute.
"When cancer cells are deprived of their mitochondrial energy-producing function, they acquire replacement mitochondria from their environment.
"While that's certainly important for keeping cells alive, we know cancer cells can generate small amounts of energy independently of their mitochondria – enough to grow and divide."
Quite unexpectedly, Berridge and his colleagues found that, in addition to generating energy, mitochondria were also essential for making precursors of nucleic acids – the building blocks of our DNA.
"This is game-changing," he said.
"If this property of mitochondria can be targeted effectively it opens the door for new types of combination cancer therapies," the Malaghan Institute's Professor Mike Berridge says. Photo / File
"While many cancer cells can survive without the energy from mitochondria, they simply cannot grow without the ability to form new strands of DNA, which we now know mitochondria play a vital role in."
While the ability to recover energy-production was an important coping mechanism in cancer's dogged resistance to drugs and treatments, being able to make new DNA was much more important in terms of a cell's ability to grow, divide and spread.
In a cancer setting, this meant the ability to form tumours.
The research, which was the collaborative efforts of nearly 50 researchers spread across eight countries including New Zealand, opened the door for a new class of therapies that more accurately target this Achille's heel of cancer.
"Not only does this work give us invaluable insight into the biology of cancer, it goes further and opens up a key target for cancer treatment," Berridge said.
"If this property of mitochondria can be targeted effectively it opens the door for new types of combination cancer therapies."
Such a drug was already used to treat arthritis, suggesting that refinement and repurposing may be possible.
"Without the ability to synthesise new DNA these cells would be much more sensitive to treatment and just won't be able to form tumours."
Despite billions of dollars worth of research by tens of thousands of leading scientists, cancer, in its many hundreds of forms, still remains one of the world's biggest killers.
In New Zealand, 60 people are diagnosed with it every day.
