Fungi may lead to cheaper cancer drug

Toronto: An anti-cancer substance which is already known to be found in yew trees can also be derived from a kind of microbial "bandage" that protects these trees from disease-causing fungi.

The findings may lead to a less expensive synthetic process for making more of the cancer-fighting substance called taxol which is currently harvested from yew bark.

This is the first study to show how fungi living naturally in yew trees serve as a combination bandage-immune system for the plant, said study co-author Manish Raizada from University of Guelph in Ontario, Canada.

Drug companies might one day harness beneficial fungi to pump out more taxol cheaply and easily to meet demand - what Raizada calls a "holy grail" for cancer drug makers.

The researchers found that naturally occurring fungi in the yew's vascular system act like an immune system to swarm a wound site and protect against invading pathogens.

The taxol fungicide is contained in "fatty bodies" that direct it only against pathogens and not the tree's sensitive tissues.

"The fatty bodies come together to form a wall and seal the wound site," Raizada said. 

Yews are ancient trees related to ginkgo and Wallemi pine, old species that have similar branch cracking and contain similar fungal species.

The researchers plan to study more about the genes and chemical pathways involved in making taxol in both trees and fungi.

The study appeared in the journal Current Biology.