Friday September 15, 2006

Compounds From Vegetables Attack Cancer Cells

One of the most complex medical challenges is to find the right mix of drugs to kill cancer tumour cells. A research team at the Christchurch School of Medicine and Health Sciences, University of Otago, has now discovered that compounds from cruciferous vegetables such a broccoli, brussels sprouts and watercress help to kill cancer cells which are resistant to other treatments.

The researchers led by Dr Mark Hampton from the Free Radical Research Group have recently had their ground-breaking study published in the American journal ‘Cancer Research’. Other members of the team that contributed to the research are Kristin Brown, Dr Susan Thomson and Dr Juliet Puller.

The University of Otago researchers have shown that naturally occurring chemical compounds known as isothiocyanates, found in cruciferous vegetables, cause cell-suicide in cancer cells, including cells that have high levels of the protein Bcl-2.

“The reason the Bcl-2 protein is dangerous is that it makes cells resistant to the normal cell-suicide or apoptosis process, that is vital for removing damaged cells from the body, “explains Dr Hampton. “A cancer cell with a lot of Bcl-2 has increased resistance to chemotherapy drugs that are used to destroy the tumour. We’ve found that Bcl-2 can’t protect cancer cells against certain isothiocyanates.”

The discovery by the University of Otago scientists opens up important avenues for new anti-cancer drugs that mimic cruciferous vegetable isothiocyanates. Such drugs would overcome the protection cancer cells get from Bcl-2 and make them more susceptible to other treatments.

The challenge now is to understand exactly how isothiocyanates work inside the cell. Dr Hampton and his colleagues have tested a variety of different isothiocyanates, and found that not all are effective in causing cell-suicide.

“This has provided us with a very valuable clue. Isothiocyanates alter many different proteins in a cell, but by focussing on proteins that are only modified by the isothiocyanates that kill the cancer cells, we have discovered a protein that could potentially control cell death.”

He says that this information could be valuable for designing and testing more refined chemotherapy drugs based on the naturally-occurring isothiocyanates. The ideal situation would be to have a new drug that effectively kills the tumour cells, but does not affect other healthy cells within the body. This type of research can be slow, but the information it yields is important in the fight against cancer.

Dr Hampton is a recipient of a Sir Charles Hercus Research Fellowship from the Health Research Council of New Zealand, and last year won a MacDiarmid Young Scientist of the Year Award for health research.

Previous funding has come from the Royal Society Marsden Fund, the Cancer Society, the Canterbury Medical Research Foundation, the Robert McClelland Trust and the University of Otago.

ENDS