How do scientists develop a new treatment for prostate cancer? First, they need a safe way to test it before they even think about trying it in humans. "Unfortunately, the tools available to researchers make it difficult to develop and test targeted immunotherapy and treatments for bone metastases, two areas of great need in prostate cancer therapy," explains Brian Simons, D.V.M., Ph.D. "New drugs are currently tested primarily on xenografts -- human cells growing in mice without a functioning immune system." But if mice don't have an immune system, they can't very well serve as models for any treatment that requires the body's own ability to fight disease. Another problem: "Very few of these models develop metastatic tumors," which limits the development of treatments for bone metastasis.

Simons has developed a new laboratory model that has the potential to do a lot of good for men desperately in need of treatment for advanced prostate cancer. Working with Edward M. Schaeffer, M.D., Ph.D., the R. Christian B. Evensen Professor of Urology, and a team of investigators, he has come up with a mouse model of bone metastatic prostate cancer that has many features of very aggressive human prostate cancer. "When injected into mice, these cells frequently form bone metastases that initially respond to anti-androgen therapy, but then become castration-resistant tumors," he says. Already, this model is being used to test new immunotherapy treatment strategies and imaging systems to detect bone metastasis.