Antarctic Sea Squirt Compound Shows Selective Melanoma-Killing Activity in USF-Led Expedition
核心洞察
A University of South Florida expedition to Antarctica studied a sea squirt whose bacterium produces a compound that selectively kills melanoma (搜索) cells without harming normal human cells.
The selectivity is considered critical for drug development, as researchers aim to treat the disease without harming the patient.
More than half of FDA-approved drugs originate from natural sources, and this discovery represents early-stage research that could eventually lead to new melanoma (搜索) therapies.
A compound produced by a bacterium living inside an Antarctic sea squirt has demonstrated the ability to selectively kill melanoma (搜索) cancer cells while leaving normal human cells unharmed, according to researchers at the University of South Florida (USF). The finding, first made 20 years ago by USF chemistry Professor Bill Baker, is now the focus of a renewed National Science Foundation-supported expedition aimed at understanding how the compound is produced and whether it could one day contribute to new therapies for one of the deadliest forms of skin cancer.
"That selectivity is critical in drug development because you want to treat the disease without harming the patient," said Baker, who co-led the research.
Melanoma (搜索) accounts for an estimated 57,000 deaths globally each year, a number that could rise to 96,000 by 2040. The highest incidence rates are found among fair-skinned populations in Australia, New Zealand, and Western Europe.
A Unique Evolutionary Laboratory
The sea squirt, or ascidian, is a sac-like marine invertebrate that lives on sloped or vertical seafloor surfaces at depths between 60 and 80 feet in the waters surrounding Antarctica. The continent's geographic and environmental isolation over millions of years has produced highly specialized organisms found nowhere else on Earth.
"The continent is unique because it has been geographically and environmentally isolated for millions of years," Baker said. "As a result, species in Antarctica have had time to evolve independently, leading to highly specialized organisms. The ascidians we study are adapted specifically to this environment and are not found anywhere else."
The ascidians, like many marine invertebrates, rely on chemical defenses to survive in harsh ocean conditions, producing compounds that can deter predators and disease. It is within this chemical arsenal that the melanoma (搜索)-killing bacterium resides.
Six Weeks Under the Ice
The USF team, joined by scientists from the Desert Research Institute and Scripps Institution of Oceanography, spent six weeks collecting specimens from beneath the Antarctic ice. Dives averaged 25 to 35 minutes, reaching maximum depths of 130 feet, with operations complicated by ice, leopard seals, changing seas, and sometimes very limited visibility.
"Every dive must be carefully planned to balance getting the work done while keeping everyone safe," said Ben Meister, USF diving safety officer who represented the university in Antarctica alongside postdoctoral researcher Sam Afoullouss from the Baker Lab.
The expedition also deployed two remotely operated vehicles to explore deeper waters, identify new collection sites, and map the distribution of ascidians across different depths and locations along the Antarctic Peninsula.
"Our expedition focused on determining where the ascidian's melanoma (搜索)-killing bacterium occurs and how widespread it is," Afoullouss said. "We also wanted to understand how it lives inside the organism and how that connects to the compounds linked to melanoma research."
From Ocean Floor to Laboratory Bench
Now back on land, the research enters its most critical phase. Specimens are divided among multiple teams focusing on DNA analysis, chemistry, and biological assessments—a process that could take months to years.
"This research is important both environmentally and medically," Baker said. "We are learning how organisms use symbiosis to survive in extreme conditions, which is still largely unknown in cold-water ecosystems like Antarctica. Understanding the source and function of this compound is critical if we hope to develop it into a drug."
The work builds on Baker's broader track record in marine natural products discovery. His previous marine discoveries have led to patented compounds with potential applications against drug-resistant malaria, cancer, and antibiotic-resistant infections, underscoring the pharmaceutical promise hidden within ocean organisms. More than half of FDA-approved drugs originate from natural sources.
The researchers caution that discoveries like this represent the early stages of a long process, but they could eventually help identify new ways to treat complex diseases.