Brain tumor radiation resistance defeated

DURHAM, N.C., Dec. 10 (UPI) -- U.S. scientists say they discovered how stem cells in a type of malignant brain cancer resist radiation, and then used a drug to reduce that resistance.

Researchers from Duke University and the Cleveland Clinic said their work was based on research showing cancer stem cells can better resist the effects of radiation than other cancer cells. The earlier research identified a signaling pathway in normal cells called "Notch" that controls cell growth and differentiation.

The researchers then identified the Notch signaling pathway as the most likely reason for the radiation resistance of the cancer stem cells.

The lead author of the study, Jialiang Wang of Duke University, said the finding marked the first report that Notch signaling in tumor tissue is related to the failure of radiation treatments.

"This makes the Notch pathway an attractive drug target," Wang said. "The right drug may be able to stop the real bad guys, the glioma stem cells."

The Duke and Cleveland Clinic researchers say they targeted a key enzyme of the Notch pathway by using drugs called gamma-secretase inhibitors. Senior author Dr. Bruce Sullenger of Duke said use of such drugs, in combination with radiation, "caused massive cell death in the tumors and significantly reduced survival of glioma stem cells."

The research is detailed in the journal Stem Cells.