A surprising discovery by Queen’s University (Canada) researchers that happened when their work took an unexpected turn may help women with advanced breast cancer respond better to conventional drug treatments.

The Queen’s team’s findings, published in the journal Cancer Research, show that a newly discovered “peptide” molecule (a chain of amino acids smaller than a protein) increases the effectiveness by 350 percent of drugs used to kill breast cancer cells.

Drs. Zongchao Jia and Vinay Singh, of the Queen’s Department of Biochemistry, initially intended to study the structure of a protein called SNCG which is implicated in drug resistance in breast cancer. When unraveling the structure proved more difficult than expected, the research team looked to a similar protein associated with Alzheimer’s Disease.

They were looking for “binding partners” of the Alzheimr’s protein, hoping to learn how the structures of the Alzheimer protein and SNCG were held together. From this information, they were able to design a completely new peptide, which blocked SNCG’s interaction with another protein, counteracting the resistance to cancer drugs. “We were excited to find that it actually can reduce anti-cancer drug resistance by three-and-a-half times,” says Jia, Canada Research Chair in Structural Biology.

Noting that the peptide itself is not a drug, Jia likens it to an ingredient in the kind of “drug cocktails” used to treat HIV/AIDS. “It has to be used in combination with a drug to be effective,” he says. “In the same way that cream flavors coffee to make it taste better, the peptide enhances the effectiveness of the most widely-used breast cancer drugs today.”

“We greatly hope this will not only increase the positive response from patients but also will make the current drug more useful by extending its impact to a wider range of people, particularly those with a resistance problem,” says Jia.

Next, Jia hopes to team up with other researchers to advance the work to the point where they can transform the peptide, called ANK, into a suitable form for “drug cocktail” therapy.

SOURCES:
Cancer Research, online edition, January 17, 2006
Queens University (‘http://qnc.queensu.ca)