June 2005

Novel approach for eradicating prostate cancer wins award for young Hebrew University researcher




A new method to facilitate the destruction of prostate cancer cells by the immunological system has been developed by a Ph.D. student at the Hebrew University of Jerusalem.

For her work in this area, Tal. Arnon was chosen as one of the recipients of the Barenholz Prize in Drug Delivery Systems, which was awarded this month during the Hebrew University Board of Governors meeting.

Tal, born in Israel, began her academic studies in the Etgar program for outstanding students at the Hebrew University at the age of 20. She received her B.S. in medical science at the Hebrew University and is currently working on her Ph.D. under the tutelage of Dr. Ofer Mandelboim at the Lautenberg Center for General and Tumor Immunology at the Hebrew University Faculty of Medicine. .

A major problem in diagnosing and treating prostate cancer � the second leading cause of cancer deaths in Western countries � is the high resemblance between tumor and normal prostate cells. This makes it very difficult to identify markers that would allow targeted treatment of tumor cells alone.

Among the cells in the immune system that protect against the growth of tumorous growths are the natural killer (NK) cells, which are able to identify and kill different tumor cells. This ability largely depends on the expression of a small family of proteins (NCRs) which specifically bind to tumors, but not healthy cells.

By applying various molecular biology techniques, Tal produced NCR proteins combined with an immunoglobulin protein. The latter is a well known marker recognized by the immune system.

By thus combining NCRs with immunoglobulin, a clear marker is created that will not only make it more feasible to identify cancerous prostate cells at an earlier stage, but also opens the way to facilitate targeted, immunological destruction of those cells.

Using mice into which human prostate cancer cells were introduced, it was shown that treatment with the biologically-engineered NCR-immunoglobulin proteins had a dramatic effect. The NCR-treated mice showed a substantial reduction in tumor progression, while a control group revealed a rapid growth of such tumors. Indeed, 50% of the treated mice recovered completely, 25% showed partial cure, while another 25% did not respond.

The results thus demonstrate an encouraging clinical potential for prostate cancer analysis and treatment. Furthermore, the engineered NCRs are also capable of recognizing many other tumors, opening an avenue for further investigation of this approach for dealing with other types of cancers.