Malaria remains among the world’s leading health problems and has retained that status for a very long time. The protozoa responsible for this disease have been found in the bodies of mosquitoes that were preserved in amber no fewer than 30 million years ago.
That lengthy track record represents a significant evolutionary head start for these ancient parasites, which have survived by finding new ways of continuing to infect victims even as those victims continued to evolve their own defence mechanisms for resisting such infection. Although the world continues its battle with the disease, researchers are now taking advantage of malaria’s biochemical sophistication to tackle another leading threat — cancer.
Mads Daugaard, a molecular biologist with the Vancouver Prostate Centre, noticed that malaria parasites possess a particular protein that targets sugar structures found in the human placenta. Those same structures characterize tumour cells, which would make this protein an ideal means of delivering medicine directly to those cells with minimal effects on the rest of a patient’s body. Daugaard and his colleagues have focused on a fragment of this protein, called VAR2CSA. “We can produce and work with this protein fragment in different settings,” he says.
The protein is now being developed into a broad specificity cancer drug by Copenhagen-based VAR2 Pharmaceuticals and Kairos Therapeutics, a Vancouver-based spin-off from the Centre for Drug Research and Development, one of Canada’s federally sponsored Centres of Excellence for Commercialization and Research. Kairos maintains a proprietary drug development platform based on a specific toxin and linker, which will accelerate the process of preparing this protein for use with approved pharmaceutical compounds.
In the meantime, Daugaard adds that the researchers have turned to the challenge of ramping up the volume production of this protein while also meeting the demands of Good Manufacturing Practice, a specific set of production requirements imposed by Health Canada on any medicinal product. “We need to transfer the protein synthesis system from shake flasks to fermentation,” he says.
As for pitting one biological bad guy — malaria — against another one — cancer — Daugaard finds that outcome to be eminently satisfying. “We can learn so much from what nature already made,” he says. “I’m very happy that we were able to transfer this and make it work as a delivery system. It’s also highly unlikely that we would be able to design a molecule or variant that would have a better affinity to the sugar molecule than what evolution has been able to produce over millions of years.”