Scientists identify important new cancer drug target

Synthetic versions of a molecule vital for keeping cell division in check could be potent anti-cancer drugs of the future, a leading Cancer Research UK scientist announces.

High levels of the molecule – called geminin – can kill cancer cells while leaving their healthy counterparts unharmed, Prof Julian Blow reveals at the charity’s first annual conference in Kenilworth, Warwickshire.

His team are now developing drugs designed to selectively destroy cancer cells by mimicking geminin’s effects.

Geminin controls the crucial process of copying DNA, which has to happen whenever a cell divides in two. When geminin is present inside cells, the process is switched off. But removing the molecule switches gene copying back on and gives cells the all-clear to divide.

Prof Blow’s team investigated the effect of giving cancer cells large quantities of geminin. They infected human cancer cells with a modified virus carrying the gene for geminin and found that it caused them to commit suicide. When they delivered geminin into healthy cells, they stopped dividing but were left unharmed.

Scientists think that healthy cells have a safety mechanism, suspending their development temporarily in geminin’s presence. But cancer cells have a defect in this system and cannot cope with exposure to the molecule.

Prof Blow says: “We think that removal of geminin will release normal cells from their limbo state, giving them the green light to start growing again. But for cancer cells it will be too late, since they will already have begun the process of programmed cell death.”

He adds: “Geminin is very effective at killing cancer cells but it is too large to be delivered as an anti-cancer drug, so we are now hunting for smaller molecules that have a similar effect.”

Prof Blow’s team are studying the structure of geminin with a view to developing a version that can be easily absorbed and that will resist being broken down inside the cell. They are also screening huge numbers of similar molecules, searching for those with geminin-mimicking effects.

Sir Paul Nurse, Chief Executive of Cancer Research UK, says: “Prof Blow’s research is an excellent example of how knowledge about the basic biology of cells has led to the identification of an important target for anti-cancer drugs.

“Cancer Research UK is committed to following up the lead as thoroughly as possible, so that we can convert the scientific discovery into real benefits for patients.”

ENDS