Sick Kids scientists discover 'off-swith' for cancerous cell growth

TORONTO (May 1, 2001) - Scientists at The Hospital for Sick Children (HSC) have identified an 'off-switch' for cancerous cell growth, opening the door for new targets in the development of anti-cancer drugs. This research is reported in the May 1 issue of the European Molecular Biology Organization Journal (EMBO).

A number of complex cellular processes regulate the workings of the human body. For example, the enzyme ILK1 (a kinase) acts as an 'on-switch' for cellular growth. In 60 per cent of human tumours, such as breast, colon and prostate cancer, ILK1 is hyperactivated, causing cells to grow uncontrollably. The laboratory of HSC scientist Greg Hannigan has identified the natural 'off-switch' for this cellular growth pathway - an enzyme called ILKAP (a phosphatase).

"This is a significant scientific discovery because ILKAP and its function had not been identified before and it could act as a tumour suppressor," said Dr. Greg Hannigan, the study's principal investigator and an assistant professor of Laboratory Medicine and Pathobiology at the University of Toronto (U of T). "While the discovery doesn't currently have a direct impact on patients, it does identify a very significant target for pharmaceutical development."

The identification of ILKAP is an important clue in understanding the biology of tumour development. This research builds on Dr. Hannigan's discovery of ILK1 while a postdoctoral fellow at U of T.

"Knowing the structure of this enzyme provides information on how to design drugs that could target the 'off-switch' and stop tumour growth by inhibiting ILK1. The next stages of research will involve screening large numbers of natural and synthetic compounds that mimic the structure of ILKAP and that would be amenable to making drugs," added Dr. Hannigan.

This research is at the in vitro (cell culture) laboratory stage. The development of new drug interventions takes many years.

This research was supported by the Canadian Institutes of Health Research, the National Cancer Institute of Canada with funds from The Terry Fox Foundation, Kinetek Pharmaceuticals Inc., and US Army Breast Cancer Research Program.

The Hospital for Sick Children is a health care, teaching and research centre dedicated exclusively to children; affiliated with the University of Toronto. Its mission is to provide the best in family-centred, compassionate care, to lead in scientific and clinical advancement, and to prepare the next generation of leaders in child health. For more information, please visit www.sickkids.ca.