Fungus produces cancer drug

From San Francisco, at a meeting of the American Association for the Advancement of Science

Several varieties of fungi that attack hazelnuts produce high quantities of the widely used cancer drug paclitaxel, researchers report. Companies currently extract the powerful but expensive drug from the bark of yew trees.

Since the early 1990s, doctors have been using paclitaxel, sold under the brand name Taxol, to fight cancers of the lung, ovary, and breast, and some other tissues. However, since paclitaxel comes from slow-growing trees, the drug is in limited supply.

In a chance discovery, Angela Hoffman of the University of Portland in Oregon and her colleagues found that several types of fungi that plague hazelnuts contain tiny amounts of the drug. While growing the fungus in a nutrient-rich broth, however, the researchers observed that the fungi produce an increasing amount of paclitaxel as sugar in the broth becomes depleted.

From the lab studies, Hoffman estimates that fungi growing in 10 liters of broth for 3 weeks could provide enough paclitaxel to treat one person’s cancer. Extracting a comparable amount from yews could take many trees and years of growing time, she says.

The researchers next plan to look for the paclitaxel-producing gene in the fungi, with the aim of ramping up production of the drug by fungi or other organisms.

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