Rochester, Minn. -- Mayo Clinic researchers working with colleagues in Germany have devised a much-needed multilevel safety feature for viruses used to treat cancer. In the process of making cancer-killing viruses more specific to cancer tumor cells, they report having improved the therapeutic effectiveness of viruses. They did this by engineering a modified measles virus that turns on only in the presence of secretions specific to malignant cancer cells.

In effect, the Mayo Clinic virus makeover uses proteins secreted by cancer cells as the unique key to the virus' ignition. Their report on the topic appears in the Aug. 1 edition of Cancer Research (http://cancerres.aacrjournals.org).

The investigation was performed in laboratory mice that were transplanted with a human cancer. The process is still experimental -- and thus, years away from clinical use in humans. However, the Mayo results may be immediately useful in designing improved cancer treatments for humans. "Our work shows that oncolytic measles virus particle activation can be made dependent on substances secreted by cancer cells, and this enhances safety," explains Roberto Cattaneo, Ph.D., lead researcher on the Mayo team. "By doing this, our study broadens the safeguarding strategies possible to tightly restrict the targeted virus to cancer cells."

Significance of the Mayo Clinic Research
The Mayo researchers say their contribution is a key advance because it provides a method of designing a therapeutic virus that is safe, stable and that reliably targets and kills cancer cells. Importantly, it appears to greatly reduce the possibility that the virus would erroneously turn on and harm the patient by causing unintended infection.

As such, the Mayo innovation of the cancer-activated virus is a helpful safety advance for the promising experimental field of "oncolytic virotherapy." The phrase refers to t
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Contact: Bob Nellis
newsbureau@mayo.edu
507-284-5005
Mayo Clinic
1-Aug-2006