This is one reason for conservation. Forget sentimentality: so many unknown organisms harbor defense mechanisms unknown to science that could be used for good purposes by humans.
In this case, the sea creature is something called a sea squirt and was discovered in 1990 off the coast of the Philippines.
Apparently, its toxin blocks uninhibited reproduction of human cancer cells while leaving healthy cells unaffected. In mice, it has shown none of the side effects of other cancer drugs:
"The animal, Diazona angulata, is a sea squirt a few inches wide that lives in colonies anchored to rocks. It was discovered offshore of the Philippines in 1990 as scientists were looking for species that might lead to useful drugs. From a few specimens, scientists extracted a tiny amount of a toxin, diazonamide A, which the animal probably uses to repel predators."
"Dr. Noelle Williams, assistant professor of biochemistry and internal medicine, led the second phase of the research, which tested the effect of a variant of diazonamide A, called AB-5, in mice with tumors."
"While all three drugs reduced tumors in the mice, the known drugs caused significant weight loss and loss of white blood cells while AB-5 caused neither side effect. "That the diazonamide toxin blocks mitosis selectively in cancer cells is almost too desirable an outcome to be true," said Dr. Steven McKnight, chairman of biochemistry and senior author of the second study."
"In a study appearing online this week in the Proceedings of the National Academy of Sciences, the UT Southwestern scientists detail how the toxin blocks uninhibited reproduction of cultured human cancer cells while leaving healthy cells unaffected.
An accompanying study in PNAS shows that, in pre-clinical trials, a synthetic form of the toxin reduced human tumors implanted in mice without the harmful side effects seen using other cancer drugs. "Diazonamide is a special molecule -- it's teaching us more than we imagined," said Dr. Patrick Harran, professor of biochemistry and a senior author on both studies."