Radiation therapy genetic switch found

DAVIS, Calif., Nov 15, 2005 (UPI via COMTEX) -- Scientists reportedly have found a genetic switch that causes cancer cells to be more sensitive to a drug given to enhance radiation therapy effectiveness.

University of California-Davis Cancer Center researchers say their discovery may help design new anti-cancer agents that enhance the effectiveness of radiation therapy with less toxicity than currently available radiosensitizing drugs.

Allan Chen, assistant professor of radiation oncology, and colleagues found Ku86, a gene involved in DNA repair, acts as a switch that, when turned off, makes cells significantly more vulnerable to the radiosensitizing property of the anti-cancer drug camptothecin.

Ku86 had no effect on the radiosensitizing abilities of other anti-cancer agents tested -- etoposide, cisplatin and vinblastine. Ku86 also had no effect on camptothecin toxicity.

The team concluded that, like a switch that controls only a certain light bulb, Ku86 uniquely affects radiosensitization, but not cytotoxicity, induced by camptothecin.

The finding is reported in the Priority Reports section of the last issue of the journal Cancer Research.

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