This Article Full Text Full Text (PDF) Supplementary Data Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hari, M. Articles by Greenberger, L. M. Search for Related Content PubMed PubMed Citation Articles by Hari, M. Articles by Greenberger, L. M.

¹ Oncology Research, Wyeth, Pearl River, New York and ² Department of Chemistry, Emory University, Atlanta, Georgia

Requests for reprints: Frank Loganzo, Discovery Oncology, Wyeth, 401 North Middletown Road, Room 4709, Building 200, Pearl River, NY 10965. Phone: 845-602-4237; Fax: 845-602-5557. E-mail: loganzf{at}wyeth.com

Resistance to paclitaxel-based therapy is frequently encountered in the clinic. The mechanisms of intrinsic or acquired paclitaxel resistance are not well understood. We sought to characterize the resistance mechanisms that develop upon chronic exposure of a cancer cell line to paclitaxel in the presence of the P-glycoprotein reversal agent, CL-347099. The epidermoid tumor line KB-3-1 was exposed to increasing concentrations of paclitaxel and 5 µmol/L CL-347099 for up to 1 year. Cells grown in 15 nmol/L paclitaxel plus CL-347099 (KB-15-PTX/099) developed 18-fold resistance to paclitaxel and were dependent upon paclitaxel for maximal growth. They grew well and retained resistance to paclitaxel when grown in athymic mice. Cross-resistance (3- to 5-fold) was observed in tissue culture to docetaxel, the novel taxane MAC-321, and epothilone B. Collateral sensitivity (3-fold) was observed to the depolymerizing agents vinblastine, dolastatin-10, and HTI-286. KB-15-PTX/099–resistant cells did not overexpress P-glycoprotein nor did they have an alteration of [¹⁴C]paclitaxel accumulation compared with parental cells. However, a novel point mutation (T to A) resulting in Asp²⁶ to glutamate substitution in class I (M40) ß-tubulin was found. Based on an electron crystallography structure of Zn-stabilized tubulin sheets, the phenyl ring of C-3' NHCO-C₆H₅ of paclitaxel makes contact with Asp²⁶ of ß-tubulin, suggesting a ligand-induced mutation. Optimized model complexes of paclitaxel, docetaxel, and MAC-321 in ß-tubulin show a novel hydrogen bonding pattern for the glutamate mutant and rationalize the observed resistance profiles. However, a mutation in the paclitaxel binding pocket does not explain the phenotype completely. KB-15-PTX/099 cells have impaired microtubule stability as determined by a reduced percentage of tubulin in microtubules and reflected by less acetylated tubulin. These results suggest that a mutation in tubulin might affect microtubule stability as well as drug binding and contribute to the observed resistance profile. [Mol Cancer Ther 2006;5(2):270–8]

Note: A preliminary version of this work was presented at the Annual Meeting of the AACR, July 2003, Washington, District of Columbia, abstract no.5770.

The current address for J.H. Nettles is Novartis Institutes for Biomedical Research, Inc., 250 Massachusetts Avenue, Cambridge, MA 02139. The current address for L.M. Greenberger is Johnson & Johnson, Pharmaceutical Research & Development, 1000 Route 202, P.O. Box 300, B354B, Raritan, NJ 08869.

³ Supplementary material for this article is available at Molecular Cancer Therapeutics Online (http://mct.aacrjournals.org/).

⁴ F. Cabral, personal communication.

⁵ The RMSD of atomic position was calculated with a custom script provided by Dr. Michael Dolan of Tripos, Inc.

Received 6/10/05; revised 10/20/05; accepted 12/16/05.

This article has been cited by other articles:

				O. Kutuk and A. Letai Alteration of the Mitochondrial Apoptotic Pathway Is Key to Acquired Paclitaxel Resistance and Can Be Reversed by ABT-737 Cancer Res., October 1, 2008; 68(19): 7985 - 7994. [Abstract] [Full Text] [PDF]

				A. Mitra and D. Sept Taxol Allosterically Alters the Dynamics of the Tubulin Dimer and Increases the Flexibility of Microtubules Biophys. J., October 1, 2008; 95(7): 3252 - 3258. [Abstract] [Full Text] [PDF]

				M. Zemskova, E. Sahakian, S. Bashkirova, and M. Lilly The PIM1 Kinase Is a Critical Component of a Survival Pathway Activated by Docetaxel and Promotes Survival of Docetaxel-treated Prostate Cancer Cells J. Biol. Chem., July 25, 2008; 283(30): 20635 - 20644. [Abstract] [Full Text] [PDF]

				J. Hoffmann, I. Vitale, B. Buchmann, L. Galluzzi, W. Schwede, L. Senovilla, W. Skuballa, S. Vivet, R. B. Lichtner, J. M. Vicencio, et al. Improved Cellular Pharmacokinetics and Pharmacodynamics Underlie the Wide Anticancer Activity of Sagopilone Cancer Res., July 1, 2008; 68(13): 5301 - 5308. [Abstract] [Full Text] [PDF]

				K. Miller, M. Wang, J. Gralow, M. Dickler, M. Cobleigh, E. A. Perez, T. Shenkier, D. Cella, and N. E. Davidson Paclitaxel plus Bevacizumab versus Paclitaxel Alone for Metastatic Breast Cancer N. Engl. J. Med., December 27, 2007; 357(26): 2666 - 2676. [Abstract] [Full Text] [PDF]

				S. Yin, F. Cabral, and S. Veeraraghavan Amino acid substitutions at proline 220 of {beta}-tubulin confer resistance to paclitaxel and colcemid Mol. Cancer Ther., October 1, 2007; 6(10): 2798 - 2806. [Abstract] [Full Text] [PDF]

				H. Yang and F. Cabral Heightened Sensitivity to Paclitaxel in Class IVa beta-Tubulin-transfected Cells Is Lost as Expression Increases J. Biol. Chem., September 14, 2007; 282(37): 27058 - 27066. [Abstract] [Full Text] [PDF]

				M.-A. Esteve, M. Carre, V. Bourgarel-Rey, A. Kruczynski, G. Raspaglio, C. Ferlini, and D. Braguer Bcl-2 down-regulation and tubulin subtype composition are involved in resistance of ovarian cancer cells to vinflunine. Mol. Cancer Ther., November 1, 2006; 5(11): 2824 - 2833. [Abstract] [Full Text] [PDF]

				R. van Amerongen and A. Berns TXR1-mediated thrombospondin repression: a novel mechanism of resistance to taxanes? Genes & Dev., August 1, 2006; 20(15): 1975 - 1981. [Full Text] [PDF]

				D. Sampath, L. M. Greenberger, C. Beyer, M. Hari, H. Liu, M. Baxter, S. Yang, C. Rios, and C. Discafani Preclinical Pharmacologic Evaluation of MST-997, an Orally Active Taxane with Superior In vitro and In vivo Efficacy in Paclitaxel- and Docetaxel-Resistant Tumor Models. Clin. Cancer Res., June 1, 2006; 12(11): 3459 - 3469. [Abstract] [Full Text] [PDF]