http://keysnews.com/node/28295
December 8th, 2010
BY ROBERT SILK Free Press Staff
rsilk@keysnews.comKEY LARGO — Most would agree that preserving the reefs of the Florida Keys are important for reasons ranging from the economic to the esoteric to the ecological.
But the discovery of a compound off Key Largo that could help cure colon cancer is illustrative of a less discussed imperative for preserving the reefs: the potential their genetic diversity holds for medical science.
“I think we’ve just skimmed the surface of what is out there,” says Kate Semon, a coral research scientist with the Florida Fish and Wildlife Conservation Commission, who has been involved with the emerging field of marine biotech.
Humans have used plants for medicinal purposes for thousands of years. In fact, plant compounds are the genesis of many modern pharmaceuticals. Quinine, used to treat malaria, for example, comes from the bark of a tree native to the South American rainforest. Aspirin comes from willow tree bark. Numbing agents, like Novocain and its more infamous cousin cocaine, come from the coca plant.
But it is only in the past few decades that scientists have turned toward the sea in search of new medications.
Part of that quest includes scouring the coral reefs, where species ranging from sponges to cyanobacteria, often called blue-green algae, are engaged in chemical warfare to fight off predators as well as competitors.
It was on Pickles Reef off of Key Largo in 2003 that Valerie Paul of the Smithsonian Marine Station in Fort Pierce gathered a sample of a seaweed called symploca, which uses its own witch’s brew of toxins to compete for space on the reef.
Her team took the puff-ball like plant back to the lab and extracted the active ingredients. Those ingredients were eventually sent off to the lab of Hendrik Luesch, an assistant medicinal chemistry professor at the University of Florida, who found that the extract was potent to cancer cells but far more benign for healthy ones.
In 2007 Luesch isolated the compound that was taking down the cancer cells. He called it “largazole” after Key Largo. Just months later, Duke University chemist Jiyong Hong was able to synthetically reproduce largazole, a crucial step that allows the drug to be manufactured in large quantities, and without constant trips to the reef.
Armed with enough of the synthetic compound to begin experimentation, Luesch tested largazole first in Petri dishes. Then he implanted it in tumor-bearing mice. In a study published last month in the peer-reviewed Journal of Pharmacology and Experimental Therapeutics, he and seven co-authors reported that screening the compound against the National Cancer Institute’s 60 cell lines “revealed that largazole is particularly active against several colon cancer cell types.”
The benefits could well be major, as colon cancer is the second largest cancer killer in the United States, according to the National Cancer Institute.
“It is potentially an additional weapon in the fight against cancer,” Luesch said, adding that he plans to do more research on how other cancers respond to largazole.
He’ll also eventually up the ante on his studies to include human cancer patients. And if all goes well he estimates largazole could be approved by the Food and Drug Administration in about a decade.
If so, it would join Yondelis and eribulin mesylate as FDA-approved cancer fighting medications that were derived from the marine environment. The active ingredient in Yondelis is modeled after the extract of a sea squirt while eribulin mesylate is a synthetic remake of a toxin found in a type of sea sponge.
Paul, from Smithsonian, says that with the oceans so vast, compounds like largazole, culled from an obscure type of seaweed on a coral reef in the Florida Keys National Marine Sanctuary, are most certainly just the tip of the iceberg.
“I think there is really tremendous potential,” she said.
For FKNMS Superintendent Sean Morton it is one more reason to preserve healthy ecosystems and coral reefs in the Keys.
“I think it is fantastic,” he said. “Biotech is certainly a growing field and I’m happy that preserving the coral reef can contribute to that.”