(+)-Discodermolide is a recently discovered polyketide natural product found to be a potent inhibitor of tumor cell growth. The molecule's carbon skeleton is made up of eight polypropionate and four acetate units with 13 stereocenters.
History
Discodermolide was first isolated in
1990 from the Caribbean marine sponge
Discodermia dissoluta by chemist Dr. Sarath Gunasekera and biologist, Dr. Ross Longley, scientists at the
Harbor Branch Oceanographic Institution. The sponge contained 0.002% of discodermolide (7 mg/434 g of sponge). Since the compound is light-sensitive, the sponge must be harvested at a minimum depth of 33 meters. Discodermolide was initially found to have
immunosuppressive and
antifungal activities.
Mechanism of action
Discodermolide has been shown to inhibit the proliferation of human cells by arresting the
cell cycle in
G2- and
M-phase. It hyper-stabilizes
microtubules, especially prevalent during
cell division, and competes with
paclitaxel for microtubulin binding, but with higher affinity. Over a variety of cell lines, activity has been measured at IC
50 = 3-80 nM.
Hyper-stabilization of the mitotic spindle causes cell cycle arrest and cell death by apoptosis.
Discodermolide is effective in paclitaxel- and epothilone-resistant cancer cells.
Total syntheses
Several
total syntheses have been published to date by Schreiber, Smith, Paterson, Marshall, and Myles. A review of the various synthetic approaches has also been published.
Clinical development
As of 2005, the
Harbor Branch Oceanographic Institution has licensed (+)-discodermolide to
Novartis, which has begun a phase 1
clinical trial. The
Amos B. Smith's research group (in collaboration with
Kosan Biosciences) has a preclinical drug development program ongoing.
The compound supply necessary for complete clinical trials cannot be met by harvesting, isolation, and purfication. As of 2005, attempts at synthesis or semi-synthesis by fermentation have proven unsuccessful. As a result, all discodermolide used in preclinical studies and clinical trials has come from large-scale total synthesis.
References
- Gunasekera, S. P.; Gunasekera, M.; Longley, R. E.; Schulte, G. K. J. Org. Chem. 1990, 55, 4912-4915.
- Gunasekera, S. P.; Pomponi, S. A.; Longley, R. E.; U. S. Patent 5,840,750, November 24, 1998. (Patent text)
- Gunasekera, S. P.; Paul, G. K.; Longley, R. E.; Isbrucker, R. A.; Pomponi, S. A. J. Nat. Prod. 2002, 65, 1643.
- Hung, D. T.; Chen, J.; Schreiber, S. L. Chem Biol. 1996, 3, 287-293. (Abstract)
- Klein, L. E.; Freeze, B. S.; Smith, A. B.; Horwitz, S. B. Cell Cycle 2005, 4, 501-507. (Article)
- Jordan, M. A. Curr. Med. Chem.: Anti-Cancer Agents 2002, 2, 1.
- Nerenberg, J. B.; Hung, D. T.; Somers, P. K.; Schreiber, S. L. J. Am. Chem. Soc. 1993, 115, 12621-12622.
- Hung, D. T.; Nerenberg, J. B.; Schreiber, S. L. J. Am. Chem. Soc. 1996, 118, 11054.
- Smith, A. B. III. et al. J. Am. Chem. Soc. 1995, 117, 12011.
- Smith, A. B.; Beauchamp, T. J.; LaMarche, M. J.; Kaufman, M. D.; Qiu, Y.; Arimoto, H.; Jones, D. R.; Kobayashi, K. J. Am. Chem. Soc. 2000, 122, 8654-8664. (Article)
- Smith, A. B.; Freeze, B. S.; Xian, M.; Hirose, T. Org. Lett. 2005, 7, 1825-1828.
- Paterson, I.; Florence, G. J.; Gerlach, K.; Scott, J. P. Angew. Chem. Int. Ed. Engl. 2000, 39, 377. (Article)
- Marshall, J. A.; Johns, B. A. J. Org. Chem. 1998, 63, 7885.
- Harried, S. S.; Yang, G.; Strawn, M. A.; Myles, D. C. J. Org. Chem. 1997, 62, 6098.
- Paterson, I.; Florence, G. J. Eur. J. Org. Chem. 2003, 2193.
- Amos B. Smith, III Current Research Projects
- Mickel, S. J. et al. Org. Process Res. Dev. 2004, 8, 92, 101, 107, 113 and 122.
- Wulff research group (PDF)
See also
External links
Chemotherapeutic agents