Turning to Nature to Improve Radiation Therapy

Donations help scientists to create more effective anticancer drugs

Radiation therapy is an essential but imperfect weapon in medicine’s arsenal against  cancer. Because it has the potential to damage healthy cells during treatment, Roswell Park scientists are working to develop new drugs to reduce or eliminate that side effect.

Radiation therapy also poses another challenge, and it’s now being addressed with
donor-funded research: how to overcome certain cancerous cells’ resistance to radiation’s impact.

“Radiation is a DNA-damaging treatment– it kills cancerous cells by acting like molecular scissors and, in a sense, snips the cell’s DNA strands so it cannot function properly and form new cells,” says Terry Beerman, PhD, of Roswell Park’s Department of Pharmacology and Therapeutics. “But if a cancerous cell survives initial radiation treatments, it can actually become more resistant to further radiation therapy, and your ‘scissors’ end up being too dull to make a difference.”

Beerman explains that radiation therapy is a chemical process inside the body.
Radiation waves require the presence of oxygen in the tumor cells in order to damage DNA. Each time radiation strikes the tumor, it also damages the tumor cells’ vascular system—reducing the supply of oxygen. Cancerous cells that survive radiation treatment then have less oxygen within them, and radiation can’t work its magic.

Fortunately, nature may have provided an answer.

“Last year we discovered that a class of naturally-occurring molecules from
a microbe family can mimic radiation’s effect. Under low oxygen conditions the
effect becomes even more potent,” said Beerman. He says the molecule doesn’t just mimic radiation’s ‘snipping’ quality when oxygen is present; it can also bind two DNA strands in a cancerous cell together when oxygen is not present. The binding acts like a glue or handcuff so the DNA can’t go out and create new cancer cells.

Beerman is now working with a chemist who is an expert in the art of genetically modifying microbes. Together, they are improving this gift from nature into a nextgeneration drug that is even more effective at killing radiation-resistant tumor cells, and that is less harmful to normal cells. “It could be used either alone, or in combination with radiation therapy,” added Beerman. “The result is that there may someday be far less chance for any radiation-resistant cell to beat the system.”