New Cancer Therapy Breakthrough

Scientists have revealed the critical role a key enzyme plays in helping cells divide in what could prove an important development for new cancer therapies.

Cells divide to form two identical cells as part of the body's natural development and regenerative processes but when cells divide in an abnormal manner, tumors can develop. A new study has demonstrated that an enzyme called Polo kinase is involved in normal cell division and that it also goes into overdrive in cancer, helping cells to multiply in an uncontrolled manner. Clinical trials on drugs that block the actions of Polo kinase were initiated in the United States in 2005 but the complete determination of how the enzyme assisted the cell-division process has not been clarified until now.

In the study, published in the November 23, 2006, issue of the journal, Nature, a team of researchers from the Universities of Manchester (UK) and Newcastle-upon-Tyne (UK) have demonstrated a new way in which the enzyme works. "Enzymes are proteins that speed up or ‘catalyze' the body's chemical reactions such as those required for normal cell division,” explained Prof. Andrew Sharrocks, lead researcher in Manchester's faculty of life sciences. "As its name suggests, the enzyme we have studied is from a group known as kinase enzymes which use a particular chemical--a phosphate--to catalyze the reactions that lead to cell division. Our study has identified a new target protein that uses these phosphate groups to switch on genes and alter the properties of cells. When the actions of enzymes like Polo kinase go unchecked, cells divide in an uncontrolled manner to form tumors. However, if we block their activity using chemical inhibitors the cells can no longer divide and the cancer cannot grow and spread.”

The identification of a new major step in which Polo kinase functions has confirmed the choice of this enzyme as a target for anti-cancer drug development and will drive efforts in this direction. In fact, as scientists now have a much greater understanding of the mechanisms involved, it might enable them to either develop more effective drugs or propose different situations in which the drug can be used.

"Kinase inhibitors are proving to be very effective at killing off rogue cells, and trials on patients elsewhere have been promising with fewer toxic effects than current cancer treatments,” remarked Prof. Sharrocks. "Our research on Polo kinase will help with this line of drug development and hopefully produce more effective kinase-blocking chemicals that will one day treat patients with different types of cancer.”


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University of Manchester
University of Newcastle-upon-Tyne