Researchers isolate molecular mechanism that spurs cancer growth

January 1st, 2009 - 11:11 am ICT by IANS  

London, Jan 1 (IANS) Researchers have identified a molecular mechanism that spurs growth of cancer cells by protecting them from chemotherapy. Both the messenger substance nitrogen monoxide (NO) and the protein ’survivin’ play a role in this process.

The results are based on a study of patients with head-neck tumours. Every year, at least 10,000 people develop malignant cancer of the head-neck region.

In this study, researchers from Johannes Gutenberg University, Mainz, led by Roland Stauber, a professor in its ENT clinic, has identified the molecular mechanism by which the messenger substance nitrogen monoxide contributes towards the growth and the resistance to treatment of head-neck cancers.

Despite a positive outcome after surgery, radiotherapy, and/or chemotherapy, the majority of these patients suffer a relapse after initial treatment, which then spreads to other parts of the body.

Nitrogen monoxide plays a role in numerous physiological but also pathological processes: Thus, for example, most cancer cells produce increased amounts of the chemical and appear to gain a survival advantage.

Until recently, it was not clear how they do this. The researchers in Mainz have now managed to demonstrate that nitrogen monoxide or the protein that produces it - known as iNOS in medical jargon - induces the synthesis of another protein called ’survivin’.

The name survivin is derived from the verb “to survive”, which also offers a clue to its function: survivin was only recently identified by researchers as one of the central factors in head-neck cancers, as it prevents the programmed death (apoptosis) of cancerous cells.

The increased formation of iNOS - and therefore the messenger substance nitrogen monoxide - results in activation of certain signal pathways in the cancer cells, which ultimately leads to an increase in the production of survivin, said a university release.

Its properties as an inhibitor of programmed cell death are in turn exploited by the cancer cells to protect themselves against attack by chemo or radiotherapy so that cancer cells employ, as it were, the “iNOS/survivin” axis as a survival aid.

The study appeared in the International Journal of Cancer.

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