Anticancer Drug Derived from Blue-Green Algae

A collaborative team of researchers has identified a potent new anti-cancer drug isolated from a toxic blue-green algae found in the South Pacific.

The properties of somocystinamide A (ScA) were recently described in an article published online in the journal Proceedings of the [U.S.] National Academy of Sciences (PNAS) the week of February 11-15, 2008. "We are excited because we have discovered a structurally unique and highly potent cancer-fighting compound,” said Dr. Dwayne G. Stupack, associate professor of pathology at the Moores University of California, San Diego (UCSD) Cancer Center (USA). "We envision it will be perfect for emerging technology, particularly nanotechnology, which is being developed to target cancerous tumors without toxic side effects.”

The ScA compound was found in the cyanobacteria Lyngbya majuscula, also known as "mermaid's hair,” collected off the coast of Fiji in the South Pacific by the laboratory of William Gerwick at Scripps Institution of Oceanography. A diverse team of researchers from UCSD's Cancer Center, and other institutions worked to identify, screen, and test marine compounds in vitro and in vivo. They found that ScA suppresses neovascularization, the formation of blood vessels that feed tumors, and had a direct impact on tumor cell proliferation.

"The compound isn't toxic to the cyanobacteria itself, but activates a ‘death pathway,' present in our cells,” said Dr. Stupack. "When the cells of the blood vessels that feed tumors become activated and proliferate, they become especially sensitive to this agent.” Dr. Gerwick noted that if a normal-sized swimming pool full of cancer cells were treated with ScA, it would take only 3 mg, about the weight of a grain of rice to kill all of the cancer cells.

Wolf Wrasidlo, Ph.D., senior project scientist at the Moores UCSD Cancer Center and first author of the study, added that the unique structure of this compound lends itself very well to nanotechnology, because it "incorporates spontaneously” into molecule-sized nanoparticles, important for the kind of highly targeted, combination therapy being developed to treat cancer. The structure is also simple enough that the scientists can reproduce it.

"ScA is the first, and most potent compound we've identified so far,” Dr. Stupack said, adding that it will not be the last, as the team has identified more than 250 unique compounds from L. majuscula alone. "But we don't yet know how abundant ScA is, or if it's feasible to harvest, so it is important that we have been able to produce this natural product in the lab.”


Related Links:
Rebecca and John Moores UCSD Cancer Center