Thursday, July 3, 2008 | A team of San Diego scientists are becoming increasingly convinced that the cure for cancer may be linked to a marine compound found within long strands of rosy-colored toxic bacteria that grow beneath mangroves in the South Pacific.
In a breakthrough discovery, researchers at the University of California, San Diego and the Scripps Institution of Oceanography identified a potent and stealthy compound in the bacteria, called “mermaid’s hair,” that can kill tumors and be delivered without harming healthy tissue — thereby avoiding a major drawback to traditional cancer therapies such as radiation treatments and chemotherapy drugs.
The findings were published early this year in an online industry journal and Dwayne Stupack, a pathology professor and one of the authors of the report, is presenting the research to international experts in France and Italy this week.
The compound, known as somocystinamide A or ScA, has the proven ability to target and destroy rogue cancer cells and stunt the growth of tumors by inhibiting the formation of the blood vessels that feed them. Just three milligrams of the compound — the size of a grain of rice — is strong enough to blast a swimming pool full of cancer cells.
“It’s very early still, but there is definitely reason to be optimistic,” said Bill Gerwick, a biochemist and researcher on the project.
Gerwick’s been looking to the sea for new cures for nearly 20 years, at least. He spent the early 1990s scuba diving throughout the South Pacific in search of marine compounds that could give rise to new therapies.
He said he was inspired by researchers at Yale University who, in the 1950s, discovered compounds in the membrane structures of sponges that eventually led to the creation of two new classes of drugs.
“It was like we had traveled to Mars,” Gerwick said of the idea of exploring the ocean for new compounds. “It was a very exciting time in the discovery of these exotic molecules. So much drug discovery is serendipitous.”
Gerwick’s laboratory team first gathered ScA from mermaid’s hair off the coast of Fiji. However, the compound is simple enough that scientists have been able to create a synthetic duplicate of it, making large-scale harvesting unnecessary and creating a ready supply of the compound that will be needed in clinical trials where toxicity levels are adjusted and appropriate dosages are determined, among other lab work.
So far, the compound has been tested on cancer cells in petri dishes and in live egg cultures. The next step is to test it in humans. The tricky part, Gerwick said, is delivering the intact compound directly to the cancer while avoiding healthy cells.
That’s where nanotechnology comes in.
Nanotechnology is a cutting-edge technology where inorganic and organic devices are constructed from tiny collections of molecules or atoms. This takes place on the scale of nanometers — billionths of a meter. The science gave rise to microchips, for example, but it’s only been used in the biotech field for about five years, according to Wolf Wrasidlo, the lead scientist for the research.
A nano-device is a smartly designed way of delivering a not-so-smart drug, he said. Because the ScA compound naturally clumps into molecule-sized bits, called nanoparticles, it can be customized through nanotechnology to target specific cancer cells and spare healthy ones.
The minute particles can act like guided missiles, ferrying injected anti-cancer drugs to a tumor. Unlike conventional therapies, the particles Wrasidlo is using are expected to carry a small molecule that can attach itself and the drug only to blood vessels that feed the tumors.
Without nanotechnology, the compound would be too risky and would “never make it to the drug market,” Wrasidlo said. “We now have the optimum way of getting the compound to the tumor and circulating it long-term throughout the body.”
Drug cargo delivered via a nano-device will be able to circulate and accumulate throughout the body while scoping out diseased cells in other areas.
“Many natural compounds aren’t too well suited to become drugs,” Wrasidlo said, but nano-enabled delivery systems can solve such problems and make it more likely that giant pharmaceutical companies will invest money in the drug.
Even so, the promise of the compound has to be tempered with the realities of the biotech industry. A revolutionary cancer-fighting drug won’t be available to the more than 10 million Americans who have some form of the disease until the research is tested in human clinical trials. Then, a new drug would have to be approved by the U.S Food and Drug Administration — a process that often takes more than a decade.
The daunting process of raising the hundreds of millions of dollars necessary to get through the critical clinical trials has been dubbed the “valley of death” among industry insiders, because so much budding research languishes after researchers fail to amass a sufficient amount of money.
“I always thought that if I discovered a new compound, if I made it and published it, someone else would pick it up” and commercialize it, Gerwick said. “I was sadly mistaken.”
Instead, science-minded academics like Gerwick and his colleagues have to focus on drumming up funds and pushing compounds through clinical trials.