Newswise — South Dakota State University scientists are investigating whether "stressing" cancer cells can make cancer radiation treatment and chemotherapy more effective.
Professor Xiangming Guan of SDSU's Department of Pharmaceutical Sciences explained that when cancer cells are tired out, they are easier to kill using free radicals, the basic mechanism behind radiation and some chemotherapy drugs. Free radicals are molecules with an unstable number of electrons. They pose a threat to cancer cells because the radicals steal electrons from the nearest stable molecule to regain their own stability. Excessive free radicals have been associated with potential destructive effects, such as aging, but these damaging effects can also be used against cancer cells. SDSU researchers have spent years developing a compound that will stress the cancer by blocking an enzyme called glutathione reductase. SDSU tested nine different compounds over the past six years before discovering the current compound in 2004, according to assistant professor Teresa Seefeldt, who has been working with Guan since 2002 on the project.
"We have identified a compound which can effectively block this enzyme and create stress in cancer," said Guan. "We have also demonstrated that the stressed cancer was more sensitive to radiation treatment in several different human cancer cells such as ovarian cancer, lung cancer, breast cancer and skin cancer."
The SDSU team hopes its method can be used in treatment for resistant cancers to combat cancer resistance by increasing its sensitivity. "Cancer cells don't always respond to treatment or they develop a resistance to radiation therapy or chemotherapy in the course of the treatment. This is a significant, clinically relevant problem," said Seefeldt. Current results show that the compound can also make cancer more sensitive to the widely used anticancer drug, doxorubicin. "Right now, we are working on expanding this method into different cancers," said Seefeldt.
Although in a very early stage, the compound SDSU is using to block the enzyme has shown potential for some unpredicted anticancer activity.
"This unexpected cancer inhibiting property could lead to a new class of anticancer drugs," said Guan.
Overall, Guan says the current results are promising. "I'm glad this approach has been recognized by the National Institutes of Health in terms of its significance. They have been funding this project for the past seven years."
SDSU professor Xiangming Guan, left, and assistant professor Teresa Seefeldt, shown here with graduate research assisant Wei Chen, right, are developing ways to improve cancer therapy through "stressing" cancer.
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