An obscure Alaska sea sponge, unknown to science until about a decade ago, shows promise as a tool to help patients fight pancreatic cancer, a notoriously deadly and hard-to-treat disease, researchers say.
The sponge, first spotted in 2005 on the floor of the eastern Gulf of Alaska off Baranof Island, holds unusual molecules that target and kill pancreatic cancer cells in the laboratory.
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The Alaska sponge now shows more promise as pancreatic-cancer fighter than any of the other sea sponges or plants, marine creatures and bacteria that Mark Hamann of the Medical University of South Carolina and Fred Valeriote of the Henry Ford Cancer Institute in Detroit have examined over the past two decades.
"This is certainly, for us, the best and most exciting looking candidate for the control of pancreatic cancer that we've come across in that 20-year period," Hamann said in a teleconference with reporters Wednesday hosted by the National Oceanic and Atmospheric Association, which is collaborating in the research.
Pancreatic cancer is one of the most difficult cancers to control and spreads rapidly to nearby parts of the body, according to the Mayo Clinic in Rochester, Minnesota. The pancreas is a part of the digestive system, secreting hormones that enable the body to process sugars.
The Alaska sponge was discovered by Bob Stone, a NOAA Fisheries biologist conducting an ocean-floor survey of coral habitat that fishery managers were interested in protecting.
It immediately stood out for its green color, contrasting with the browns common to Southeast Alaska sea sponges, said Stone, who was in the submersible vessel doing the survey. It looked like a sponge from the faraway Aleutians, he said.
"The second I saw it, I thought I should collect it," he said.
The green, pitted, golf-ball-sized Gulf sponge turned out to be related to those Aleutian green sponges but was a separate species: Latrunculia austini. No common name has yet materialized, but some NOAA scientists have taken to calling it "moon crater sponge."
The sponge, which is now confirmed to exist in a few clusters in the eastern Gulf and in spots ranging south to waters off Washington state, grows at a depth of 230 feet to 720 feet, far from the sun's light and warmth.
Those conditions might be critical to the sponge's cancer-fighting qualities, said Doug DeMaster, science director for NOAA Fisheries' Alaska Fisheries Science Center.
"It's likely that this sponge has a unique chemical composition because it has adapted to this cold, dark habitat," he said at the news conference.
The moon crater sponge is part of a trove of cold-water corals and sponges newly discovered at the bottom of the Gulf and Bering Sea.
Some, like the moon crater sponge, have been found in regular research surveys that map out fish habitat. Many others were found during a special three-year NOAA project, conducted from 2013 to 2015, that resulted in documentation and mapping Alaska's abundant coral and sponge species.
A 2015 report by Stone and NOAA colleague Chris Rooper identified 137 coral species and 196 sponge species in Alaska waters, some not previously documented. Stone and another colleague last year reported on two new sponge species in the Gulf and the range extension of another two species, one of them previously known only in Japan.
Ocean exploration off Alaska, probably as active as that in any other U.S. marine region, will continue to produce surprises, Stone said.
"There's just so many animals out there that we're going to continue to find new discoveries for a very, very long time," he said at the news conference. "In fact, I'm sure that there's a lot of stuff we've collected that we don't even realize is new."
Hamann and Valeriote, who have worked for several years with NOAA, are among the biomedical researchers exploring natural sources for compounds that can treat cancer and other serious diseases.
Biomedical researchers have zeroed in on sea sponges in particular, and past research into cold-water sponges from Arctic and subarctic waters off Russia, Sweden, Norway and other areas has turned up some compounds that might be useful in fighting leukemia and infectious diseases.
Among the thousands of sea sponges that he and other biomedical researchers have examined, the green Alaska sponge stands out, said Valeriote, whose lab focuses on difficult-to-treat cancers like pancreatic and ovarian cancer.
The molecule in it that is shown to kill cancer cells in the laboratory is unlike anything that he has seen among all those sponges, except for one specimen collected in Indonesia, he said.
The next steps for researchers will include attempts to collect more of the special sponge compounds — a challenge, because the cancer-cell-killing molecules exist only in very low quantities.
Bringing the chemical compound from the depths of the Gulf to cancer patients' medicine cabinets promises to be a laborious process.
The molecule exists in only very low concentrations in each sponge, so collections could be a challenge. There is a possibility of replicating the chemical structure with other source material, Hamann said.
Preclinical trials and clinical trials, if they happen, would be years into the future. So far, no traditional pharmaceutical companies have been involved in the research, and for the past two decades those companies have shied away from this type of early research, leaving scientists to rely on biomedical companies with backing from venture capitalists or government, Valeriote said.
In Alaska, the cancer-fighting findings help show the value of continued marine exploration, DeMaster said.
"The discovery of this green sponge shows the promise of the untapped potential of the ocean, the possibility that a life-saving medical discovery is within our reach," he said.
Recent discoveries of new and rare species in Alaska marine waters extend beyond corals and sea sponges. An ultra-rare snailfish — one of only about a dozen specimens ever documented — was found in last year off the Aleutians.
Also in the nearshore waters off the Aleutians, a new species of sea star was found during past years' surveys and described in a 2015 study. And an entire new-to-science genus and family of sea anemone discovered off the Aleutian island of Adak was described in a study published in October.
More than tiny creatures are being discovered. Residents of St. George Island in the Pribilof Islands identified a new-to-science species of beaked whale that apparently spends most of its time swimming in the deepwater canyons; the rare whale, which locals found as a partial carcass that washed ashore in 2014, was described in a scientific paper published last year.
New knowledge about the green sponge's cancer-fighting qualities could add to an ongoing debate about protections for Alaska coral and sponge habitat.
Bottom trawling, with its nets that can scrape the seafloor, is a practice considered to be the most serious threat to those habitats, though sponges are also at risk of being pulled out of the sea as bycatch of commercial fish harvests.
Fishery managers have already closed several areas of Alaska coral and sponge habitat to bottom trawling. In 2005, the North Pacific Fishery Management Council, which regulates commercial fishing in federal waters off Alaska, closed most of the waters off the Aleutian Islands and some parts of the Gulf to bottom trawling to protect cold-water corals, sponges and other features of the seafloor.
The council has turned down proposals to prohibit trawling in the deep underwater canyons of the Bering.
Existing protections for corals and sponges are substantial, said Stone, who noted that the area where the first green sponge was found has been protected from trawling since 1996.
Whether those protections are adequate or more are needed is "obviously an ongoing discussion," he said. "Over the next couple of years, the next decade or two, we'll continue to work on that."