A team from the University of South Florida (USF) has returned from a six-week expedition to Antarctica, where they collected samples of ascidians, or sea squirts, whose bacterial toxins may offer a new treatment for melanoma, the deadliest form of skin cancer.
Expedition and Discovery
Led by Bill Baker, professor of chemistry at USF, the research focused on toxins produced by ascidians as a defense mechanism against predators. Previous studies by the team showed that these toxins killed melanoma cells in mice without harming the animals. “The good news is it didn’t kill the mice. It did kill their cancer, so we know it has the physiological properties to act like a drug,” Baker said.
The expedition, funded by the National Science Foundation, involved divers descending up to 130 feet for about half an hour at a time. Ben Meister, USF professor and diving safety officer, noted challenges such as ice, leopard seals, and limited visibility. “Every dive must be carefully planned to balance getting the work done while keeping everyone safe,” he said.
Pathway to Human Trials
Baker acknowledged that developing a safe and effective anti-melanoma drug is a long process requiring strictly regulated trials. However, the expedition’s findings could accelerate the timeline. “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 explained.
The research will now move to laboratories, with partnerships at the Desert Research Institute and Scripps Institution of Oceanography. The team aims to understand how the melanoma-killing bacterium lives inside the microorganism and their ecological relationship. “Things we learn from these field studies are going to help us advance this thing when we start doing those animal models and human models,” Baker said.
Synthetic Reproduction and Sustainability
To avoid overharvesting from Antarctica, the team plans to synthetically reproduce the toxin. “From a basketball size collection of ascidians we might get one-thousandth of that. Obviously we cannot collect 1,000 basketball quantities from the Antarctic, that would destroy the ecology,” Baker noted. “One of the things we have to do is figure out how to make this stuff in the lab.”
Baker, who began his career in marine biology and chemistry in 1990, emphasized that more than half of FDA-approved drugs originate from natural sources. He described the melanoma discovery as “sort of a career pinnacle.” “Killing cancer cells in a petri dish is one thing, but going beyond that is much harder, and the fact that we’ve cleared some of those higher hurdles is really exciting for me. Now we’ve got to make the next hurdle,” he said.
