Coral Ecosystems May Hold Cancer Cures, but Face Threats

  • June 15, 2018
  • by Holly Binns

A marine biologist explores the importance of protecting coral habitats to safeguard potential medical discoveries.

See Pew's conservation work in the Gulf of Mexico.

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Sponges live from the shallows close to shore to thousands of feet below the surface. Together with corals, they make up unique communities that barely have been studied but, like some other organisms, are natural disease fighters. Scientists believe they hold important properties that already are producing treatments for some cancers.

Corals and sponges may appear primitive, but “they have genes, proteins, and metabolic pathways that are similar to ours,” says  Pomponi, who is research professor and executive director of the Cooperative Institute for Ocean Exploration, Research, and Technology at the Harbor Branch Oceanographic Institute of Florida Atlantic University.

The medical promise of sponges and corals is one of the driving forces behind efforts to conserve their valuable habitats, which are mainly threatened by damaging fishing gear, but also from oil and gas development as well as changing ocean conditions. In the Gulf of Mexico, fishery managers are considering a proposal to safeguard coral and sponge hot spots by restricting damaging fishing gear, such as trawls, anchors, and bottom longlines, in as many as 23 sites deemed a high priority for protection. (If you want to encourage managers to protect corals and sponges, sign our petition.)

Even with the deep sea’s promise for human health solutions, scientists don’t have plans to harvest corals and sponges for medical uses. Instead they would take samples they could use to try and replicate in a lab the promising properties sponges and corals produce in the wild.

“It would be economically and ecologically unrealistic to exploit these habitats, especially because corals and sponges provide habitat as well as feeding and breeding grounds for fish, crabs, shrimp, and many other species,” says Pomponi, who is an expert on the hundreds of different species of sponges throughout the Gulf of Mexico and beyond.

Scientists have discovered the potential for new medications underwater. This magnified photo shows a glass sponge (Aphrocallistes beatrix), which contains a potent anti-cancer compound.

Sponges and corals are natural disease fighters

Sponges have existed in the oceans for 600 million years, surviving through mass extinctions and severe environmental stresses.

They can’t move. To defend themselves sponges produce chemicals, some of which are shown to fight infection in humans. Sponges further protect their territory by stopping other organisms’ cells from dividing and taking over—similar to how drugs stop the spread of cancer.

In fact, in more than 45 years of studying sponges Pomponi has never seen one with a tumor. “Somehow they make sure cancer cell precursors either repair themselves or die,” she says. Pomponi thinks that could help us better understand how cancer develops in humans—and how we might even prevent it. “We can not only tap into their arsenal of chemicals, but also their metabolic pathways for human health applications,” she says.

Discoveries from sponges already have provided antibiotics and cancer drugs, and their skeletons are being studied to develop ways to grow bone for grafting and dental implants. Some species in the Gulf of Mexico are used in drugs to treat breast cancer. Scientists see similar potential in deep-sea corals, which also have existed for millions of years. Researchers have discovered that one type of gorgonian coral, known as sea fans, contains powerful anti-inflammatory chemicals. Some soft corals have potential anti-cancer and antiviral properties, and bamboo corals may also be useful in bone grafting. 

Shirley Pomponi carries a sponge she retrieved from deep underwater using a remotely operated vehicle.

Human activity threatens to erase potential cures 

Pomponi’s institute has been exploring the Gulf of Mexico and other parts of the world, and researching marine-derived chemicals, since 1984. Yet with much of the Gulf and seas in the rest of the world unexplored, the race is on between those seeking beneficial discoveries and human activities that could destroy a potential cancer cure before it’s detected.

The Gulf’s jewels have already been compromised, Pomponi says. In one case, promising research on melanoma was slowed when scientists, seeking more samples of a key sponge, returned to where they had found it to discover the sponges gone and the area heavily damaged by trawls. Scientists working on treatment for Alzheimer’s disease encountered a similar situation—nearly obliterated habitat. Those researchers eventually found one small sample, after combing through 30,000 photos from the area to locate a still-viable specimen.

“We want to avoid a situation where the environment is damaged and some unique animal that produces a chemical that could cure cancer or other dreaded diseases is destroyed,” Pomponi says. “Who knows what we’ll lose?”

In The Bahamas, Pomponi dives in shallow waters to explore sponges and octocorals, marine animals that form fragile ecosystems.