The opium poppy is a fertile plant: not only is it the source of illicit heroin and the painkiller morphine, but its derivatives can also be used to make the antidote to overdoses of these drugs, naloxone. The fruitful flower, formally known as papaver somniferum, also gives rise to a drug called noscapine, a promising cancer-fighting agent already used in some countries as a cough-suppressant.
In 1998, researchers at Emory University in Atlanta first showed that noscapine could fight tumors. Since then, research on animals and human cancer cells has suggested that it can shrink breast and prostate cancers and possibly prevent metastasis, the spread of tumors throughout the body that tends to cause cancer death.
However, producing noscapine is laborious, requiring cutting open individual poppy seed capsules. Further, the poppy plants bred for the industrial manufacture of commercial opioids are high in the chemicals necessary to make those drugs, but low in noscapine. Indeed, some opium poppies don’t make any noscapine at all.
A new study, which was published online in Science, could make synthesizing noscapine much easier. By cross-breeding poppy plants that made noscapine and those that did not, researchers were able to locate a cluster of 10 genes inherited together, which is responsible for the production of the chemical.
“The fact that the genes are grouped in a cluster means that plant breeding becomes faster and easier. [We] are using this discovery to develop high-yielding commercial noscapine poppies in order to establish a reliable route of supply,” said Tim Bowser, a study co-author who leads research and development for GlaxoSmithKline’s Australian opiates division, in a statement.
Australia is the world’s leading producer of legal opioids, with Turkey coming in second. (Turkey used to be a major source of heroin until a switch to legalized poppy growing for medical use was negotiated with the U.S. in the late ’60s and early ’70s; as I’ve argued before, Afghanistan’s opium problem might be similarly resolved.)
Because noscapine is an approved drug in some countries and has a good safety record, some physicians are already using it off-label to treat cancer. Data suggests noscapine shows promise against some treatment-resistant ovarian cancers and for multiple myeloma, lung cancer, colon cancer and breast and prostate tumors. But while early clinical trials are ongoing, none have been published so far.
Although the doses of noscapine used to treat cancer are far higher than those used as cough medicine, side effects are reportedly fewer than with traditional chemotherapy.
In 2009, Johnson & Johnson bought a pharmaceutical company, Cougar Biotechnology, that has been developing noscapine. The new discovery for noscapine synthesis should boost pharmaceutical industry interest in the drug and, hopefully, spur faster development. Some support for the current research came from GlaxoSmithKline.