Drugs used to treat other conditions may stop brain tumour growth

01 May 2007

Dr Peter Dirks Canadian Cancer Society researchers have found that a number of drugs currently in use for other brain conditions may stop the growth of the stem cells responsible for cancerous tumours in the brain.

Dr Peter Dirks led the team that tested a variety of chemical compounds that were known to affect brain cell chemical or electrical activity on the growth of normal neural (nervous system) stem cells. The active compounds affect pathways involved in neural signaling transmission and are already in use for a variety of human brain disorders.

The research team, which Dr Dirks led with Dr Mike Tyers from the Lunenfeld Research Institute at Mount Sinai Hospital in Toronto, found that 160 of the 1,300 chemical compounds tested interfered with growth of normal neural stem cells in a culture system, and that a number of these agents also worked to suppress the growth of brain tumor stem cells. The results of the study were published in May 2007 in Nature Chemical Biology.

“These early results are quite exciting because they show that these drugs may affect the growth of the stem cells that may be the source for initiation of brain tumors. These findings may lead to new drug therapies for brain cancer,” says Dr Dirks, a scientist and neurosurgeon at Toronto’s Hospital for Sick Children. Some of the agents showed significant selectivity for the brain tumor stem cells, compared to normal stem cells.

The research team will now test the most promising compounds to determine if they can stop the growth of human tumour cells grafted into the brains of mice. If those studies are successful, it may be possible to move quickly to human trials because these drugs are already being used to treat other disorders, Dr Dirks says.

Dr Dirks made international headlines in 2004 when he published findings identifying the brain cancer stem cells that are responsible for the growth of brain cancers. The findings suggested that developing treatments that target these stem cells could be more effective than current therapies, which show limited effects on the bulk of tumour cells but may not kill the rare numbers of more dangerous stem cells.

Brain cancer is the leading cause of cancer death in children and one of the most difficult adult cancers to treat. In 2007, an estimated 2,600 Canadians will be diagnosed with brain cancer and 1,700 will die of it.