THE KINETICS OF TAXOID ACCUMULATION IN CELL SUSPENSION CULTURES OF TAXUS FOLLOWING ELICITATION WITH METHYL JASMONATE

Authors: KETCHUM, RAYMOND - CORNELL UNIVERSITY; Gibson, Donna; CROTEAU, RODNEY - WASHINGTON STATE UNIV; SHULER, MICHAEL - CORNELL UNIVERSITY

Submitted to: Biotechnology and Bioengineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Paclitaxel (Taxol) is a potent chemotherapeutic drug with potential against a range of cancers. The very limited supply of this drug from the original source, Pacific yew bark, however, prompted the development of alternative sources of production, including the use of plant cell cultures. In this report, we describe how taxane production can be greatly increased using the compound methyl jasmonate. By optimizing both the concentration of the elicitor, methyl jasmonate, and the timing of elicitation, we have achieved a rapid accumulation of taxanes. Using our methods and cultures, we have observed some of the greatest paclitaxel concentrations and the most rapid productivity rates reported to date. These improvements in taxane production in cell culture should prove useful to achieving commercial success with this technology.

Technical Abstract: Cell suspension cultures of Taxus canadensis and Taxus cuspidata rapidly produced paclitaxel (Taxol) and other taxoids in response to elicitation with methyl jasmonate. By optimizing the concentration of the elicitor, and the timing of elicitation, we have achieved the most rapid accumulation of paclitaxel in a plant cell culture, yet reported. The greatest accumulation of paclitaxel occurred when methyl jasmonate was added to cultures at a final concentration of 200 uM on day 7 of the culture cycle. The concentration of paclitaxel increased in the extracellular (cell-free) medium to 117 mgl-1 within 5 days following elicitation, equivalent to a rate of 23.4 mgl-1d-1. Paclitaxel was only one of many taxoids whose concentrations increased significantly in response to elicitation. Despite the rapid accumulation and high concentration of paclitaxel, its concentration never exceeded 20% of the total taxoids produced in the elicited culture. Two other taxoids, 13-acetyl-9-dihydrobaccatin III and baccatin VI, accounted for 39 to 62% of the total taxoids in elicited cultures. The accumulation of baccatin III did not parallel the pattern of accumulation for paclitaxel. Baccatin III continued to accumulate until the end of the culture cycle, at which point most of the cells in the culture were dead, implying a possible role as a degradation product of taxoid biosynthesis, rather than as a precursor.