“All you see are various shades of white, blue, and black,” postdoctoral scholar Sam Afoullouss said of the Antarctic landscape. “Then you go under the water, and it’s a whole range of colors that you’ve never seen before.”
Afoullouss and Ben Meister, a University of South Florida research diving safety officer, went there in February to collect sea squirts, also called ascidians. A USF-led team from the Desert Research Institute and the Scripps Institution of Oceanography spent six weeks on the expedition, which the National Science Foundation funded. Divers went down as far as 130 feet for about half an hour at a time. Meister said the team made more than 160 dives.
The prize is a molecule called palmerolide. Bill Baker, a USF chemistry professor, said it is a metabolite of a sea squirt found only in Antarctic waters. It targets a particular enzyme in melanoma, he said, “and kills the melanoma without killing the patient. That’s a good thing.”
What the mice showed
Work already done by Baker’s team found that the compound killed melanoma cells in mice. “The good news is it didn’t kill the mice,” Baker told the Guardian. “It did kill their cancer, so we know it has the physiological properties to act like a drug.”
He called the result “sort of a career pinnacle.” Killing cancer cells in a petri dish is one thing, he said, and clearing the higher hurdles is much harder. “Now we’ve got to make the next hurdle.”
Supply is the next obstacle. Researchers need hundreds of milligrams to grams of the compound, and a basketball-size collection of sea squirts yields about one-thousandth of that, Baker said. Taking 1,000 basketballs’ worth from Antarctica would damage the ecology. The Joint Genome Institute in California is synthesizing the genes behind the substance, with the goal of growing more of it in a lab. A specialty lab at USF will study its ecology.
Baker has studied this sea squirt for 20 years. Any drug would still face a long path of strictly regulated, ever-larger trials. “We need grams of material to do a bigger study in mice, perhaps go into other animal models, and if we can prove the safety, we can actually start some human trials,” he said.
The cost of the dives
Meister listed what the divers faced: “We had ice, we had depth, we had cold, we had leopard seals, we had the dry suit.” The cold can bring on “this really intense, cold, like, external ice-cream headache.”
Alison Murray of the Desert Research Institute, the expedition’s chief scientist, said the team surveyed 200 miles of the Antarctic peninsula, far more area than before.
Dr. Rick Jacobson, a USF assistant professor and skin cancer surgeon at Tampa General Hospital, said he still sees high volumes of new patients every week even as screening rates rise. Florida ranks second in the country for new melanoma diagnoses, according to a 2018 AIM at Melanoma Foundation blog, and the Skin Cancer Foundation puts survival at 99% when the disease is caught early.
Sources
- Tiny Antarctic sea creature could be key to treating melanoma, researchers say
- USF researching Antarctic sea squirt that could be tool in skin cancer fight
