Kiwis break ground with DNA finding

The image shows the observed transfer of mitochondria in a nanotube between breast cancer cells in a mouse. Photo / Malaghan Institute

Discovery offers new avenue for targeting debilitating brain and muscle diseases

A Kiwi-led research breakthrough could see defective genes replaced with custom-designed DNA - a move that would combat hundreds of different diseases.

The technology could ultimately help millions of people suffering from conditions ranging from hearing problems to brain function issues.

Although such advances are still emerging, the groundwork has been laid by Kiwi researchers who are the first in the world to demonstrate the movement of a key form of DNA between cells in an animal tumour.

The research centres on mitochondrial DNA. Unrelated to the nuclear DNA which creates our primary genetic profile, this DNA encodes key proteins in the mitochondrial machinery that converts energy from food into a form of chemical energy that is particularly important for brain and muscle function.

Up until now, scientists had believed these genes stayed within cells, except during reproduction: a fundamental concept in cell biology taught even in schools.

That has now been overturned by research published today in the journal Cell Metabolism and led by Professor Mike Berridge of the Wellington-based Malaghan Institute of Medical Research. In experiments, mitochondrial DNA was removed from mouse models of breast cancer and melanoma.

However, the scientists later observed this DNA being naturally transferred back from surrounding normal mouse tissue, before the cancer cells went on to form tumours that spread to other parts of the body.

Professor Berridge said the discovery could boost understanding of human diseases, since defective mitochondrial DNA is known to account for about 200 diseases and is implicated in many more. Many of the diseases - affecting hearing, eyesight, brain and muscle function - frequently occurred in young people and became more debilitative as the person matured.

The work could also usher in a new field where synthetic mitochondrial DNA is custom-designed to replace defective genes, he said.

"It's probably also relevant to cancer, but we really don't understand how yet."

Q & A

What was the discovery?
A Kiwi-led research team demonstrated the movement of mitochondrial DNA between cells in an animal tumour. After mitochondrial DNA was removed from breast cancers and melanomas in mice, replacement mitochondrial DNA naturally shifted from surrounding normal tissue. After adopting the new DNA, the cancer cells went on to form tumours that spread to other parts of the body.

Isn't that bad news?
In many ways, no. It's a leap in the science of cellular biology, and could boost the understanding of human diseases other than cancer, since defective mitochondrial DNA accounts for about 200 diseases and is implicated in many more.