Researchers block cancer-linked enzyme

In collaboration with the Press Association

UK scientists have discovered a way to block the action of an enzyme that, when faulty, plays a crucial role in about ten per cent of cancers.

The enzyme, called phosphoinositide 3-kinase (PI3K), is already the subject of intense scrutiny because under normal circumstances, it plays a key role in regulating cell division and growth - two things that go wrong in cancer, and several studies have pointed to an involvement in cancer development.

A team led by Dr Roger Williams at the Medical Research Council's Laboratory of Molecular Biology and Jonathan Backer at the Albert Einstein College of Medicine has discovered a way to target the specific part of the faulty version of PI3K identified in cancer cells.

Dr Williams explained: "The PI3K enzyme plays a key role in controlling how human cells behave and its mutation can lead to numerous types of cancers.

"But before the enzyme is active, it has to release a partner protein that acts as a molecular brake."

Publishing their findings in Science, the team reveal that they developed a three-dimensional model for how this 'molecular brake' is applied, and then created a mutated partner protein which in turn acts as a brake for the cancer-causing enzyme.

"This intervention may be able to stop a cancerous cell from dividing uncontrollably," Dr Williams concluded.

Professor Julian Downward, head of signal transduction at Cancer Research UK's London Research Institute, said: "This is an exciting early scientific discovery that gives us an important insight into the structural make-up of an enzyme that is thought to be involved in a number of cancers.

"We hope this fundamental scientific research will one day lead to improved therapies for the ten per cent of cancers that are caused by this specific gene defect. "Drugs that target PI3K are shortly going to enter early phase clinical trials and we look forward to seeing how these new treatments perform in patients."