Anti-psychotic drug gives clues to target cancer 'stem cells'

In collaboration with the Press Association

A key type of cancer cell that drives tumours' growth can be neutralised without damaging healthy cells, according to researchers in Canada.

Laboratory experiments by scientists at McMaster University in Ontario found that an anti-psychotic drug called thioridazine can transform so called 'cancer stem cells' into non-cancerous cells that no longer divide.

Many researchers believe that cancer stem cells are the source of new cancer cells within a tumour. They are thought to be resistant to current treatments, explaining why some cancers are so difficult to cure.

The scientists used pioneering robotics to test more than a dozen different compounds to identify the drug, which is already known to be relatively safe for humans at certain doses. The research is published in the journal Cell.

It is hoped that this method could be used in the future to find other potential cancer drugs.

"The unusual aspect of our finding is the way this human-ready drug actually kills cancer stem cells; by changing them into cells that are non-cancerous," said Dr Mick Bhatia, scientific director of McMaster's Stem Cell and Cancer Research Institute.

"Now we can test thousands of compounds, eventually defining a candidate drug that has little effect on normal stem cells but kills the cells that start the tumour," he added.

Researchers are already planning a clinical trial of thioridazine in combination with standard anti-cancer drugs for adults with acute myeloid leukaemia.

Dr Tim Somervaille, from Cancer Research UK's Paterson Institute for Cancer Research, said that the work represents one of a number of strategies researchers are using to identify how to target cancer stem cells and kill off tumours.

He added: "It's too early to say whether thioridazine could be used to treat cancer patients, but the research opens up some interesting questions for further investigation. Use of thioridazine at dose levels required to treat cancer may well result in significant side effects that limit or prohibit its use. Further research will be needed before we can be sure."

Copyright Press Association 2012

References

  • Sachlos, E. et al. & Bhatia, M. (2012). Identification of Drugs Including a Dopamine Receptor Antagonist that Selectively Target Cancer Stem Cells Cell DOI: 10.1016/j.cell.2012.03.049