Re-Found Sponge Could Help Cure Cancer
Nov. 10, 2003 -- For nearly 20 years, divers searched in deep and shallow water. They scoured wide ocean swaths. But their prize — a gray, rocklike sponge — remained elusive. Until now.
In October a team from Harbor Branch Biomedical Marine Research, based in Fort Pierce, Fla., finally zeroed in on the sponge's hideout while on a research cruise in the Bahamas.
"We were really excited," recalled Amy Wright, director of the group. "I was just dancing around."
By carefully plotting out every feature of landscapes where bits of the sponge had been found before, Wright and her colleagues came up with a likely hideout. Sure enough, they found healthy populations of the sponge at a depth of 1,000 feet in an area known as the Dead Zone.
Why so much to-do about a little sponge? Researchers believe the yet-unnamed species holds medical potential and could, quite literally, save lives.
Endless Finds, Easy to Lose
When bits of the sponge were first found in 1984, preliminary tests showed a chemical within it was about 400 times more potent than the drug currently used to treat breast cancer, Taxol. The initial tests were so promising that lab workers went ahead to see if the chemical would work to kill cancer cells injected into mice.
Those results were also promising. Then they ran out of sponge.
Running out of supplies of a potential marine medicine is a common problem for those searching for cures in the ocean.
Since the ocean covers 70 percent of the Earth's surface and remains largely unexplored, scientists believe it may hold many more cures. Right now about 16 compounds derived from marine species are in clinical trials. Most of these drugs are for treating different forms of cancer since cancer foundations have funded ocean exploration for biomedical research.
But the vastness of the ocean is also its drawback — since species can quickly be lost in its waters. That's why Wright devised a hunt for the gray sponge.
"I got a pattern for a depth range and for the kinds of terrain when we found it before," she said.
Now that researchers have replenished their supply (their submersible vessel yanked 1,200 grams of the sponge from the rocky area of the ocean floor), Wright is hopeful a new, highly effective pancreatic cancer drug will emerge within 10 years or possibly only three or four.
"We already know it's going to work in animal models," she said. "So we know it should eventually work in people."
Long Haul
Others take a more cautious view.
"We are always optimistic that this type of early testing will lead to a new drug," said William Fenical, director of the Center for Marine Biotechnology and Biomedicine at Scripps Institution in La Jolla, Calif. "Unfortunately, it rarely does."
Still, Fenical points out, there are rare successes. In fact, his lab has produced at least two of them.
Fenical focuses mostly on microbes that live in the muck of ocean bottoms and on ship's sides. One such creature, a brown invertebrate with stringy tufts called Bugula, produces a chemical that is now in phase 2 clinical trials as a treatment for everything from leukemia to kidney cancer.
"The phase 2 clinical trial is when the rubber hits the road and patients who have no recourses try the drug," explained Fenical.
Even if the Bugula drug proves effective in the phase 2 trials, many hurdles remain before it can be approved by the Food and Drug Administration for general use. It took two decades, for example, before Taxol, which is derived from the western yew tree, hit pharmacy shelves.
Wright adds that laboratory teams will also need to pinpoint the exact source of the potent chemical within the newly re-found sponge. It could be contained within the creature's cells, but it may also be a product of microbes that live in the sponge.
That will require many more hours of peering into microsopes at tiny scraps of the precious sponge. But, as Fenical points out, the possibility of discovery is always worth the slog.
"The statistics are that about one in 100 actually leads to significant utility," he said. "But, be sure, without this important process, we wouldn't have the effective drugs currently in use."