Australian team spots gene linked to blood vessel growth in tumours

The discovery by Australian Scientists of a gene that appears to be linked to blood vessel growth in tumours in mice, may one day lead to better treatments for cancer in people.

The scientists from the Western Australian Institute for Medical Research in Perth, have identified a gene - RGS5 which makes a signalling molecule that can reverse angiogenesis - the growth of blood vessels inside a tumour.

It is the uncontrolled growth of blood vessels and the formation of abnormal blood vessels inside tumours that 'feed' them, allowing them to grow and stops the immune system from attacking them.

Many cancer therapies currently in use target the blood vessels in tumours, which are thought to feed the cancer cells.

Associate professor Dr. Ruth Ganss who led the research team says by modulating the blood vessels within the tumour, the whole tumour environment can be changed which makes it more susceptible to treatment.

Dr. Ganss says this offers an alternative to just killing the blood vessels with the cancer therapy.

For the research the scientists used genetically-altered mice which developed pancreatic cancer and half of them had the RGS5 gene missing.

Dr. Ganss says the tumours grew in both groups of mice, but the blood vessels looked very chaotic and abnormal in the mice which had the gene and looked normal when the gene was missing.

For the next step the researchers injected anti-cancer cells into both groups of mice and it was found that the mice without the gene were much more responsive to treatment and lived longer.

The researchers say the anti-cancer cells went directly into the tumour, the tumour shrank, there was less tumour burden and the mice survived longer.

In the group of mice with the gene the anti-cancer cells did not reach the tumour in sufficient numbers to have any impact on the tumour.

The result meant the mice without the gene lived at least 10 weeks longer and researchers found their tumours were half the size.

Dr. Ganss says the research shows that RGS5 is a master gene in angiogenesis and when it is removed, angiogenesis reverses and the blood vessels in tumours appear more normal.

The team say the protein, RGS5 could well be a target for anti-cancer therapy, however while the finding could help improve cancer therapy, it does not represent in any way a cure.

The research is published in the journal Nature.