DNA ends hold secrets to combating ageing and cancer

An enzyme that is billions of years old holds the promise of renewing ageing tissues and combating cancer.

Known as telomerase, the biological enzyme replenishes DNA at the tips of chromosomes " an area called the telomere. A telomere is like the little plastic tip at the end of a shoelace (an aglet) that protects it from fraying.

Professor Elizabeth Blackburn from the University of California said that telomerase levels control the fine balance between ageing and immortality.

Without telomerase, chromosome ends dwindle away as cells divide, and this shortening of chromosomes contributes to the wear and tear of age.

"Recent clinical and experimental observations suggest there is a link between telomerase and diseases of ageing such as heart disease," Blackburn said.

"If we could reactivate telomerase function in ageing cells, we may be able to slow down the ageing process by repairing damaged tissues and organs.

"But telomerase is the Dr Jekyll and Mr Hyde of cells. It can help us live longer, but too much of it in the wrong cells is associated with cancer."

Cancer cells often have high telomerase levels which contribute to making these cells immortal, ie, they divide indefinitely.

Blackburn said that this property of cancer cells could be exploited.

"Developing new drugs that interfere with telomerase in tumours may be an effective way of fighting cancer," she said.

Blackburn will discuss her research program at the 11th International Congress of Human Genetics in Brisbane, 6-10 August 2006.