Fish toxin appears to kill tenacious cancer cells

[RandyW]

Fish toxin appears to kill tenacious cancer cells

By Kyung M. Song

Seattle Times health reporter

For years, Antimycin has been used as a fish poison, dumped into lakes and ponds to kill unwanted species.

Now it may turn out to have a more life-saving use: Scientists at the Fred Hutchinson Cancer Research Center say it could kill stubborn cancer cells that resist chemotherapy or radiation.

If the research were to bear fruit, scientists say, it could lead to new drugs to knock out the most tenacious cancer cells so that radiation or chemotherapy would work better.

Scientists have known about "survival proteins" in some cancer cells that make them resistant to therapy. But a chemically modified version of the fish toxin appears to hunt down the cells with particularly high levels of the proteins and kill them.

"The high-protein cells are the problem. They're the ones that survive" chemotherapy or radiation, said David Hockenbery, a Hutchinson Center researcher and the principal investigator of the research, which appears in the July issue of Molecular Cancer Therapeutics.

In addition to Hockenbery, six other researchers from the Hutchinson Center and the University of Washington conducted the study.

Targeted therapy is fertile ground for cancer research, in part because current therapies can be tough. For instance, chemotherapy kills healthy cells, as well as cancerous ones, and sometimes makes patients vulnerable to infection.

High levels of the survivor proteins, Bcl-2 and Bcl-xLwere first discovered in non-Hodgkin's lymphoma. But they also are present in varying degrees in many types of cancer, including liver, lung and breast cancers, Hockenbery said.

Finding ways to inhibit those proteins offers a chance to fight cancer on a molecular level, he said.

The fish toxin is sold commercially as Fintrol, by the company Aquabiotics, of Bainbridge Island. Hockenbery and his colleagues have modified it so it is chemically different from Fintrol — pouring it into ponds wouldn't kill fish.

Hockenbery stresses that the research is in early stages and is far from clinical trials on humans. Investigators need to learn more about the proteins' role in cancer-cell survival and whether other compounds might also work to eradicate them.

Hockenbery has founded a private company that has licensed patents that are held by the Hutchinson Center for new uses of the antimycin compound. The parties would share profits from any drugs that result from the research.

Kyung Song: 206-464-2423 or ksong@seattletimes.com

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