Salk researchers develop novel glioblastoma m...( LA JOLLA CAResearchers at the Salk I...)

LA JOLLA, CAResearchers at the Salk Institute for Biological Studies have developed a versatile mouse model of glioblastomathe most common and deadly brain cancer in humansthat closely resembles the development and progression of human brain tumors that arise naturally.

"Mouse models of human cancer have taught us a great deal about the basic principles of cancer biology," says Inder Verma, Ph.D., a professor in the Laboratory of Genetics. "By definition, however, they are just that: approximations that simulate a disease but never fully capture the molecular complexity underlying disease in humans."

Trying to mimic randomly occurring mutations that lie at the heart of all tumors, the Salk researchers used modified viruses to shuttle cancer-causing oncogenes into a handful of cells in adult mice. Their strategy, described in the Jan. 4, 2009 online issue of the journal Nature Medicine, could not only prove a very useful method to faithfully reproduce different types of tumors but also to elucidate the nature of elusive cancer stem cells.

The most frequently used mouse cancer model relies on xenografts: Human tumor tissue or cancer cell lines are transplanted in immuno-compromised mice, which quickly develop tumors. "These tumors are very reproducible, but this approach ignores the fact that the immune system can make or break cancer," says first author Tomotoshi Marumoto, Ph.D., a former postdoctoral researcher in the Verma lab and now an assistant professor at the Kobe Medical Center Hospital in Kobe, Japan. Other animal models either express oncogenes in a tissue-specific manner or shut down the expression of tumor suppressor genes in the whole tissue. "But we know that tumors generally develop from a single cell or a small number of cells of a specific cell type, which is one of the major determinants of the characteristics of tumor cells," explains postdoctoral researcher and co-author Dinorah Friedmann-Morvinski.