DOHA—In shallow waters not far from the bustling dhow docks of Doha, Fahed Al-Jamali wades around looking for sponges to scoop out. They grow plentifully just south of the city, on the hard rock bed of the coral reef areas.
Many researchers across the globe, like Al-Jamali, are looking into sponges as a potential source of cancer drugs. Because sponges use chemical defenses and not shells or claws to survive, they are regarded as rich with pharmaceutical opportunity.
After collecting samples, Al-Jamali, an assistant professor at Qatar University’s College of Arts and Sciences, will head back to his lab. The prize isn’t actually the sponge tissue itself, but rather the microbes that dwell within it.
“Many species of bacteria live within sponges,” he says, “and then there are other species of fungi and micro-algae too.”
Sponges, though lacking brains and hearts, are actually animals. They’re considered the evolutionarily oldest multi-cellular animals that still exist today. Most of them are sedentary, clinging to hard rocks.
Their lack of movement makes sponges vulnerable to predators, but that’s where their microbes come in. Biologists now believe that the resident microorganisms, and not necessarily the sponges themselves, may produce poisons that help protect the sponges from predators.
Researchers have had some success in the past in using natural compounds to halt the growth of cancers. The drug Taxol is one of the most commonly cited examples. “It was derived from the Pacific yew tree,” says Christopher Twelves, professor of clinical cancer pharmacology and oncology at the University of Leeds. “That remains the single most important drug to treat cancer.”
As countries get wealthier, their people start to die from different diseases—moving away from infectious diseases toward noncommunicable ailments. The Arab world is no exception—especially given that smoking is common. More and more people in the region are living to an age at which they are more likely to get cancer. After hunting for anti-cancer compounds in land life, the scientific focus has now shifted toward the seas. “The majority of the earth is covered by water, and marine resources haven’t been so well explored,” explains Twelves.
Twelves helped conduct one of the first human trials for a cancer drug called Yondelis, which originally came from chemicals extracted from sea squirts, animals that live on the plankton and other detritus they filter out of the water.
Al-Jamali, along with colleagues, is also collecting samples from locations such as the Red Sea, hoping to find more of such cancer-fighting chemicals.
Back at the lab, the Al-Jamali’s sponge tissues are bathed in a solvent such as methanol or ethanol to help remove the chemical extracts. These are then tested against cancerous cell lines grown in the lab.
Some of the compounds are toxic to all types of cancer cells; others are more selective.
If any of these extracts show promise in slowing, halting or killing the cancer cells, the next stage is to identify the responsible compound within the extract and purify it.
For now, Al-Jamali is still testing compounds in cells, but eventually, if the compounds show strong potential, tests will move on to trials with animals and then humans. But this process, says Al-Jamali, could take more than a decade and rack up considerable costs—for which he would likely need a pharmaceutical industry partner.
The main challenge, says Twelves, is scaling up concentrations of the compound high enough to fight human cancers. “For some compounds you would need the whole global population of the sponge to get just one test tube,” he says.
There are a few options. The first is to try and farm the sponge, but that can also prove inefficient. The second is to culture the microbe that secretes the compound, but it can be a challenge to get the conditions just right for bacteria are used to growing in a sponge. The third option is to synthesize the drug.
But complex organic molecules can prove difficult to reproduce in the laboratory. “Even with modern chemistry, it can take a long time to synthesize,” says Twelves.
It may take many years of trial and error before patients reap the benefit of Al-Jamali’s wading in Qatar’s warm waters. But researchers say such marine exploration is worth the searching and could save many lives in the future.
AddThis Sharing ButtonsShare to FacebookShare to TwitterShare to Email