BOZEMAN--Taxomyces andreanae may be the world's first fungus known to make the anti-cancer drug taxol, but the Montana microbe probably won't be the one tapped to make commercial amounts of the medicine.
Named after co-discoverers Andrea and Don Stierle of Montana Tech, the fungus was isolated from a yew tree near Glacier National Park five years ago. But since then, co-discoverer Gary Strobel at MSU-Bozeman has found several moldy medicine makers that far outdo T. andreanae in taxol production.
One of the front runners is a fungus from an Asian yew plant. It makes 1,000 times more taxol than the original Montana fungus, said Strobel.
He thinks this new fungus may be one for focus under the agreement signed yesterday between the New York-based drug maker Bristol-Myers Squibb and Cytoclonal Pharmaceutics Inc. of Dallas.
Cytoclonal has the original license to develop the MSU taxol makers and has significantly boosted production during the last four years, said company president Arthur P. Bollon. Now the sublicense adds Bristol-Myers Squibb's fermentation resources to potentially enhance development of microbial fermentation of taxol, said Bollon.
"Microbial fermentation is the mainstay for economic production of most antibiotics and other important drugs," he said.
If successful, it would be the first non-plant source of taxol, which now is extracted from the needles and bark of the endangered yew trees, said MSU intellectual property officer Becky Mahurin.
Strobel has sampled yew trees from Nepal, the Himalayas and across North America and found taxol-making fungi in every one of them.
"As a whole, yew is a microbial treasure trove of novel and interesting microbes interacting with each other and the plant," Strobel wrote in a 1996 paper published in the Journal of Industrial Microbiology.
Strobel thinks taxol-making microbes evolved to protect the trees from a group of root infecting fungi that thrive in moist environments. Taxol attacks these fungi the same way it attacks human cancer cells, he said.
He says the large number of endophytic organisms--microbes that live in association with higher life forms---makes a strong case for preserving biodiversity around the world. The microbes may make other compounds that could be useful to human medicine, he said.
"Given the large numbers and varieties of higher plants, the numbers and kinds of their associated microfungi must be enormous," Strobel wrote.