A toxic chemical produced by tiny marine microbes have been modified and successfully deployed against laboratory models of colon cancer, according to researchers at the University of Florida.
The UF medicinal chemists describe how they took a generally lethal by-product of marine cyanobacteria and made it more specifically toxic - to cancer cells.
When the scientists gave low doses of the compound to mice with a form of colon cancer, they found that it inhibited tumour growth without the overall poisonous effect of the natural product.
Even at relatively high doses, the agent was effective and safe.
"Sometimes nature needs a helping human hand to further optimise these products of evolution to treat human diseases," said Hendrik Luesch, Ph.D., an associate professor of medicinal chemistry at UF's College of Pharmacy.
The researchers synthesized several apratoxin compounds that were similar to the original except for slight differences in composition, designing one that proved to be extremely potent against the cancer cells in cultures and in mice, but without the overwhelming toxicity.
The compound acts as a single agent to reduce levels of two types of proteins that are targeted by cancer research labs around the world - growth factors, and enzymes called tyrosine kinases, which act as receptors for the growth factors.
Known as apratoxin S4, the compound strips colon cancer cells of their ability to both secrete and use naturally occurring factors that fuel growth - something that Luesch, postdoctoral chemist Oi-Yen Chen, Ph.D., and assistant scientist Yanxia Liu, Ph.D., say is a powerful "one-two punch" against mushrooming populations of cancer cells.
The scientists published their findings in ACS Medicinal Chemistry Letters.