RESEARCH POSTER PRESENTATION DESIGN © 2011

www.PosterPresentations.com

Towards the Synthesis and Biological Evaluation of 2nd-Generation Taxoid SB-T-1216

Paclitaxel and docetaxel are among the most widely used chemotherapeutic

agents for the treatment of a variety of cancers, such as breast, ovarian, and

non-small cell lung cancer. However, these taxoids do not show efficacy

against drug-resistant tumors. With the development of the β-Lactam Synthon

Method (β-LSM), a series of new generation taxoids were prepared, which

exhibit at least 2 orders of magnitude greater activity against a number of

drug-resistant cell lines. SB-T-1216 is one such highly potent 2nd-generation

taxoid. In order to synthesize this drug, enantiopure β-lactam was prepared via

the chiral ester-enolate imine cyclocondensation and the Staudinger [2+2]

ketene-imine cycloaddition, followed by enzymatic kinetic resolution. SB-T-

1216 is subsequently obtained by the ring-opening coupling of this

enantiopure β-lactam to a modified baccatan, followed by deprotection. The

synthesis of SB-T-1216 will be presented. This material will be used to further

ongoing research efforts towards understanding the detailed mechanism of

action of this next generation taxoid.

1.0 Introduction

1.1 Cancer

2.0 Synthesis of Enantiopure β-lactam

2.1 Staudinger [2+2] Ketene-Imine Cycloaddition Followed by Enzymatic Kinetic Resolution7-9

Modification of the C-10 Position: C-7 protection followed by C-10 acylation

3.0 Synthesis of SB-T-121614

4.0 Biological Evaluation of SB-T-121615

6.0 References1. Malumbres, M., Barbacid, M. Cell cycle, CDKs and cancer: a changing paradigm. Nat. Rev. Cancer. 2009, 9, 153-166.

2. Siegel, R., Ward, E., Brawley, O., Jemal, A., Cancer statistics, 2011. CA Cancer J Clin. 2011, 61, 212-236.

3. Rowinsky, E., Donehower, R. Paclitaxel (Taxol). J. Med. 1995, 332, 1004-1014.

4. Ojima, I., Miller, M. Chemistry and Chemical Biology of Taxane Anticancer Agents. The Chem. Rec. 2001, 1, 195-211.

5. Higgins, CF., Linton, KJ. The ATP switch model for ABC transporters. Nat. Struct. Mol. Biol., 2004, 11(10), 918-26.

6. Cancer multidrug resistance. Nat. Biotechnol. 1999, 17, 94–95.

7. Palomo, C., Jesus, M., Inaki, A., Oiarbide, G.M. Assymetric Synthesis of β-lactams by Staudinger Ketene-Imine Cycloaddition Reactions. J. Org. Chem., 1999, 1999(12),

3223-3235.

8. Brieva, R., Crich, J.Z., Sih, C., Chemoenzymatic Synthesis of the C-13 Side Chain of Taxol: Optically Active-3-Hydroxy-4-Phenyl β-lactam Derivatives. J. Org. Chem.,

1993, 58, 1069-1075.

9. Ojima, I., Recent Advances in the β-Lactam Synthon Method. Acc. Chem. Res. 1995, 28, 383-389.

10. Sharpless, B., Kold, H., VanNieuwenhze, M. Catalytic Asymmetric Dihydroxylation. Chem. Rev. 1994, 94, 2483-2547.

11. King, B., Sharpless, B. An efficient synthesis of enantiomerically pure trans-2-phenylcyclohexanol. Tetrahedron Lett. 1994, 35, 5611-5612.

12. Ojima, I., Slater, J., Kuduk, S., Takeuchi, C., Gimi, R., Sun, C., Park, Y., Pera, P., Veith, J., Bernacki, R. Syntheses and Structure-Activity Relationships of Taxoids Derived

from 14-β- Hydroxy-10-deacetylbaccatin III. J. Med. Chem. 1997, 40, 267-278.

13. Ojima, I., Habus, I., Zhao, M., Zucco, M., Park, Y., Sun, C., Brigaud, T. New and Efficient Approaches to the Semisynthesis of Taxol and its C-13 Chain Analogs by Means

of the β-Lactam Synthon Method. Tetrahedron. 1992, 4, 6985-7012.

14. Ojima, I., Slater, J., Michaud, E., Kuduk, S., Bounaud, P., Vrignaud, P., Bissery, M., Veith, J., Pera, P., Bernacki, R. Syntheses and Structure-Activity Relationships of the

Second-Generation Antitumor Taxoids: Exceptional Activity against Drug-Resistant Cancer Cells. J. Med. Chem. 1996, 39, 3889-3896.

15. Ojima, I., Kovář, J., Ehrlichová, M., Šmejkalová, B., Zanardi, I., Gut, I. Comparison of Cell Death-inducing Effect of Novel Taxane SB-T-1216 and Paclitaxel in Breast

Cancer Cells. Anticancer Res., 2009, 29(8), 2951-2960.

16. Ojima, I., Jaracz, S., Chen, J., Kuznetsova, L. Recent advances in tumor-targeting anticancer drug conjugates. Bioorg. Med. Chem., 2005, 13(2005), 5043–5054.

7.0 Acknowledgements

-This research was supported by a grant from the

National Cancer Institute (CA 103314 to I.O.)

-The authors would also like to thank URECA for

allowing them the opportunity to present this

research.

Cancer is a complex class of diseases that results from the loss of

mechanisms that regulate cellular proliferation. Tumorous cells accumulate a

number of mutations and defective modifications that results in constitutive

mitogenic signaling. Furthermore, these cells respond abnormally to

corrective, anti-mitogenic efforts.1 The ramification of this synergistic interplay

is the rapid, unscheduled proliferation of these cells and the subsequent

formation of a tumor. As the second leading cause of death within the United

States, cancer continues to remain a major problem in public healthcare.2 It is

therefore imperative that efficient pharmaceutical drugs are created for the

treatment of its various forms.

(1) Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400

(2) ICB&DD, State University of New York at Stony Brook, Stony Brook, NY 11794-3400.

Adele Whaley1, Anushree Kamath1,2, Jacob Vineberg1, Iwao Ojima1,2

1.2 Paclitaxel and Docetaxel- Mechanism of Action

1.3 Expression of MDR Phenotypes

Paclitaxel and docetaxel are categorized as microtubule-stabilizing anticancer

agents. These taxoids bind to the β-tubulin subunit of the tubulin heterodimer,

the primary constituent of cellular microtubules, and accelerates its

polymerization. Microtubules play a critical role in the formation of the mitotic

spindle during cell division, and are also important in many vital interphase

activities.3 In the presence of these abnormally stable microtubules, mitotic

arrest is induced, eventually leading to apoptosis of the cancerous cells.4

Paclitaxel and docetaxel are relatively ineffective against cancerous cell lines

expressing multidrug resistant (MDR) phenotypes. The principle mechanism

behind MDR cancers has been largely attributed to the presence of two

molecular pumps in tumor cell membranes that actively expel cytotoxic agents

from their interior; the P-glycoprotein pump (Pgp), which is an effective ATP-

binding cassette (ABC) transporter, and the multidrug resistance-associated

protein (MDP).5,6 Because the new generation taxoids are not effective

substrates for the Pgp pump, they are more effective at treating tumors that

express the MDR phenotype.

2.2 Chiral Ester-Enolate Imine Cyclocondensation10-13

Modification of the C-13 Position: Ojima-Holton coupling

Effect of paclitaxel and SB-T-1216 at death inducing

concentrations on the DNA histogram of MDA-MB-435 and

NCI/ADR-RES cells after a 24 h incubation period. The cells

were stained with propidium iodide and analyzed by flow

cytometry. 15

-Enantiopure β-lactam was prepared in good yield via the chiral ester enolate-imine

cyclocondensation and the Staudinger [2+2] ketene-imine cycloaddition.

-SB-T-1216 will be obtained in the ring opening coupling of this enantiopure β-lactam to a modified

baccatan followed by deprotection

-SB-T-1216 is a potent second generation taxoid that is more effective than paclitaxel, especially

against breast cancer cell lines expressing MDR phenotypes. Like its parent taxoid, SB-T-1216 is a

microtubule stabilizing agent that promotes the formation of microtubule bundles in interphase cells.

-Due to its increased cytotoxicity, SB-T-1216 has been shown to induce cell death at lower

concentrations than its parent taxoid, especially in the case of drug-resistant cell lines. While the IC50

(concentration of taxoid resulting in 50% of living cells in comparison with the control) of SB-T-1216 in

the drug-sensitive human breast cancer cell line MDA-MB-435 was 0.6 nM versus 1 nM for paclitaxel,

its IC50 in the drug-resistant human breast cancer cell line NCI/ADR-RES was 1.8 nM versus 300 nM

for paclitaxel. 15,16

Effect of paclitaxel and SB-T-1216 on the formation of

interphase microtubule bundles after a 24 h incubation period

in the drug sensitive human breast cancer cell line MDA-MB-

435 and the drug resistant human breast cancer cell line

NCI/ADR-RES. Microtubules stained with Cy3-conjugated

anti-tubulin antibody (red). Cell nuclei stained with DAPI

(blue).15

5.0 Conclusions

Effect of SB-T-1216 on the growth and survival of MDA-MB-435 and NCI/ADR-RES cells after a 96 h incubation period. Control cells (C)

were inoculated without SB-T-1216. The cells were seeded at 1 x 104 cells/100 μl of medium in the well. The dotted line represents the

number of cells of the inoculum. Each point represents the mean of 8 separate cultures SEM. 15