Scientist develops poison pill to kill cancer cells


A SCIENTIST in Belfast has developed a way to pop a poison pill into breast cancer cells that causes them to self-destruct. The cancer cells are destroyed but healthy cells are left completely untouched.

The pill is a gene that produces poisonous nitric oxide. Once the gene is inserted in the cell’s own DNA it begins producing the substance and kills off the cell.

Dr Helen McCarthy, of the school of pharmacy at Queen’s University Belfast, has spent the last 10 years studying the powerful anti-cancer action of nitric oxide. “We have shown huge anti-tumour effects but hadn’t been able to get a targeting system,” she said yesterday.

She has now successfully merged her nitric oxide gene with a new delivery system, a “designer biomimetic vector” that readily carries the gene into breast cancer cells while leaving normal tissues alone. Details of her work – funded by the Breast Cancer Campaign – were published yesterday in the International Journal of Pharmaceutics.

The carrier is a man-made protein, built of the same building blocks used in the body’s own proteins. It can be changed as required to target any cell type or biochemical and can successfully install the nitric oxide gene in breast cancer or other cells, she said. Her method is known as gene therapy because it involves using a functioning gene to deliver a medical treatment. “In order to make gene therapy work you need to get the DNA into the cell,” she said.

The carrier does this by being able to find the cancer cells, open them up and then take the gene and plug it into the cell’s nucleus. Once there, it begins producing nitric oxide, either killing the cell outright or leaving it weakened and twice as susceptible to radiation treatment or chemotherapy, she said. The technique works well in cell cultures in the lab and looks like being particularly useful in patients where secondary cancers have formed.

She wants to develop it as a stable dry powder that can be reconstituted and injected into the patient. “The idea is this will be delivered systemically around the body and be delivered to the other tumours,” Dr McCarthy said.