By Angus Dalton
British nobleman Lord Carnarvon was one of the first people to step into the rediscovered tomb of King Tutankhamun and behold its treasures: gold chariots, scarab pendants, a statue of Anubis and the pharaoh’s famed death mask with eyes of obsidian and quartz.
Carnarvon’s untimely death, five months later in April 1923, helped spawn the myth of the pharaoh’s curse – that anyone who disturbs a mummy’s tomb is doomed to misfortune.
King Tutankhamun’s stone sarcophagus was lifted in 2007 so the pharaoh’s remains could be moved to a climate-controlled glass box within his tomb in the Valley of the Kings, Egypt.Credit: AP
Some scientists suspect the real killer, however, was infection by a toxic fungus that lay dormant in the tomb like a booby trap: Aspergillus flavus. Now the fungus is again at the centre of intrigue after researchers in the US crafted the deadly spores into a compound that can kill cancer cells.
In the search for new drugs, scientists have been studying a group of natural molecules called RiPPs (ribosomally synthesised and post-translationally modified peptides).
Many of these tiny proteins have proved toxic to infectious microbes and cancer cells, which is why researchers are on the hunt for new types of RiPPs to test their medical potential.
‘We often think of fungi as causing disease or food spoilage, but this is an example of them holding the key to treating diseases.’
Dr Justin Beardsley, University of Sydney
Thousands of these molecules have been found in bacteria but only a few from fungi, which is why researchers from the University of Pennsylvania went looking in Aspergillus.
They found new types of RiPPs with a structure of interlocking rings and tested them against human leukemia cells. Some of the molecules blocked the growth of the cancerous cells.
Scientists then added a fat molecule present in the royal jelly that bees feed their larvae. The fat molecule, or “lipid”, helped the cancer-busting RiPPs to infiltrate leukaemia cells, and together the experimental combination performed as effectively as two existing leukaemia drugs.
“Cancer cells divide uncontrollably,” said the Nature Chemical Biology study’s senior author, Associate Professor Xue Gao. “These compounds block the formation of microtubules, which are essential for cell division.”
Aspergillus fungi can cause a deadly lung infection.Credit:
The molecules didn’t have an effect on breast, liver or lung cancer cells. A molecule that only interacts with a specific type of cell can make for a useful drug, however, because there’s often a smaller risk of side effects.
This is very early research in terms of the molecules’ potential to develop into a medicine that might one day work in people. (Many things can kill cancer cells in a dish, so the saying goes, including a handgun.)
The researchers said their “curse to cure” study underscores the broader potential in nature for the discovery of new treatments.
Of an estimated 10 million fungi species, only 150,000 have been officially described, said Associate Professor Justin Beardsley, an Aspergillus expert from the University of Sydney who wasn’t involved in the study.
“We often think of fungi as causing disease or food spoilage, but this is an example of them holding the key to treating diseases,” he said.
“This is why it’s vital that we protect biodiversity and ecological health, and keep studying the fungi of the world so we don’t miss out on undiscovered benefits in the future.”
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