根據研究指出唾液酸轉移酶的異常表現量與許多癌症有所關連。因此，發展能調控唾液酸轉移酶活性的抑制劑，進而抑制或減緩疾病的生理過程之藥物引起我們高度興趣。
本文所合成之藥物主要是以石膽酸結構中的C-ring (C-11/C-12) 嵌入雙鍵作為基底藥物 (化合物EY-22)。以脫氧石膽酸作為起始物，先將C24位置的羧酸和C3位置的羥基進行保護，然後將C12位置的羥基進行mesylation。而為了得到雙鍵而進行demesylation時，發現產物與異構物的比例為1:1，因此改變不同反應條件來找到適當的反應條件，使異構物的比例大幅地減少。最後，將保護基都去除掉，成功得到化合物EY-22。
參考本實驗室先前合成具有活性的石膽酸衍生物中，挑選出抑制效果較好的官能基 (如：aspartic acid、NBD和4-Nitrobenzoic acid等) 作修飾，成功合成出化合物EY-36、EY-37、EY-39、EY-43、EY-45和EY-46。同時為了探討在C-ring上有無羥基或帶有雙鍵結構，它們對於抑制α2,3-唾液酸轉移酶效果的差異性，因此設計合成C-ring上具有羥基的化合物DX-5。最後，將所有合成的化合物對乳癌細胞MDA-MB-231作細胞傷口癒合的活性測試，以定性實驗的方式來觀察到化合物EY-36、EY-39和EY-45有抑制轉移的潛力。

Aberrant expressions of sialyltransferases (STs) have been reported to positively correlate with many cancers. Therefore, we interest that the development of sialyltransferase inhibitors to modulate sialyltransferase activity and thus alleviate or inhibit physiological processes (e.g., alteration of sialylation in cell surface and sialylation of glycoproteins/glycolipids) caused by sialyltransferases.
In this thesis, we initially designed a potential STs’ inhibitor containing an olefin moiety within C-ring (C-11/C-12) of the lithocholic acid as a parent skeleton (compound EY-22). Synthesis of EY-22 was carried out from deoxycholic acid as the starting material. First, both the carboxylic acid at C-24 and the hydroxyl group at C-3 of deoxycholic acid were selectively protected. The protected deoxycholic acid was esterified to yield the required mesylate ester (mesylation of the hydroxyl group at C-12), which was subsequently converted to the protected lithocholic acid with an olefin at C-11 by the method of demesylation. However, demesylation resulted in a mixture compounds with the presence of desired product and steroidal rearrangement compound in the ratio of 1:1. Efficient formation of demesylation product was obtained from modification of reaction conditions. The final product EY-22 was accomplished after removal of the remaining protecting groups. A series of EY-22 based derivative, EY-36、EY-37、EY-39、EY-43、EY-45 and EY-46 (containing Asp, Glu, NBD and 4-nitrobenzoic acid moieties), were successful prepared according to the procedure described previously.
Interestingly, effective disruption of wound closure was observed for cells cultured in the presence of derivatives EY-36、EY-39 and EY-45 compared to deoxycholic acid and DX-5. Assays of sialyltransferase inhibition are underway.

1. Varki, A., Glycan-based interactions involving vertebrate sialic-acid-recognizing proteins. Nature 2007, 446 (7139), 1023-9.
2. Cabral, M. G.; Piteira, A. R.; Silva, Z.; Ligeiro, D.; Brossmer, R.; Videira, P. A., Human dendritic cells contain cell surface sialyltransferase activity. Immunol. Lett. 2010, 131 (1), 89-96.
3. Boons, G. J.; Demchenko, A. V., Recent advances in o-sialylation. Chem. Rev. 2000, 100 (12), 4539-66.
4. De Clercq, E., Antiviral agents active against influenza A viruses. Nat. Rev. Drug. Discov. 2006, 5 (12), 1015-25.
5. Harduin-Lepers, A.; Vallejo-Ruiz, V.; Krzewinski-Recchi, M. A.; Samyn-Petit, B.; Julien, S.; Delannoy, P., The human sialyltransferase family. Biochimie 2001, 83 (8), 727-37.
6. Schaub, C.; Müller, B.; Schmidt, R. R., Sialyltransferase inhibitors based on CMP-quinic acid. Eur. J. Org. Chem. 2000, 9, 1745-58.
7. Rao, F. V.; Rich, J. R.; Rakic, B.; Buddai, S.; Schwartz, M. F.; Johnson, K.; Bowe, C.; Wakarchuk, W. W.; Defrees, S.; Withers, S. G.; Strynadka, N. C., Structural insight into mammalian sialyltransferases. Nat. Struct. Mol. Biol. 2009, 16 (11), 1186-8.
8. Chiu, C. P.; Watts, A. G.; Lairson, L. L.; Gilbert, M.; Lim, D.; Wakarchuk, W. W.; Withers, S. G.; Strynadka, N. C., Structural analysis of the sialyltransferase CstII from Campylobacter jejuni in complex with a substrate analog. Nat. Struct. Mol. Biol. 2004, 11 (2), 163-70.
9. Hildebrandt, H.; Becker, C.; Gluer, S.; Rosner, H.; Gerardy-Schahn, R.; Rahmann, H., Polysialic acid on the neural cell adhesion molecule correlates with expression of polysialyltransferases and promotes neuroblastoma cell growth. Cancer Res. 1998, 58 (4), 779-84.
10. Gessner, P.; Riedl, S.; Quentmaier, A.; Kemmner, W., Enhanced activity of CMP-NeuAc:Galβ1-4GlcNAc: α2,6-sialyltransferase in metastasizing human colorectal tumor tissue and serum of tumor patients. Cancer Lett. 1993, 75 (3), 143-9.
11. Dall'Olio, F.; Malagolini, N.; di Stefano, G.; Minni, F.; Marrano, D.; Serafini-Cessi, F., Increased CMP-NeuAc:Galβ1,4GlcNAc-Rα2,6sialyltransferase activity in human colorectal cancer tissues. Int. J. Cancer 1989, 44 (3), 434-9.
12. Naito, H.; Ma, Y.; Uemura, K.; Arano, Y.; Kawasaki, T., Metabolic properties of normal and mutant mannan-binding proteins in mouse plasma. BBRC 1999, 256 (1), 231-4.
13. Burchell, J.; Poulsom, R.; Hanby, A.; Whitehouse, C.; Cooper, L.; Clausen, H.; Miles, D.; Taylor-Papadimitriou, J., An α2,3 sialyltransferase (ST3Gal I) is elevated in primary breast carcinomas. Glycobiology 1999, 9 (12), 1307-11.
14. Picco, G.; Julien, S.; Brockhausen, I.; Beatson, R.; Antonopoulos, A.; Haslam, S.; Mandel, U.; Dell, A.; Pinder, S.; Taylor-Papadimitriou, J.; Burchell, J., Over-expression of ST3Gal-I promotes mammary tumorigenesis. Glycobiology 2010, 20 (10), 1241-50.
15. Hatanaka, Y.; Kaneoka, Y., Preparation of cytidine analogs and CMP-sialic acid analogs. Chem. Abstr. 1993, 119, 49839v.
16. Schaub, C.; Muller, B.; Schmidt, R. R., New sialyltransferase inhibitors based on CMP-quinic acid: development of a new sialyltransferase assay. Glycoconjugate J. 1998, 15 (4), 345-54.
17. Müller, B.; Martin, T. J.; Schaub, C.; Schmidt, R. R., Synthesis of phosphonate analogues of CMP-Neu5Ac determination of α (2-6) -sialyltransferase inhibition. Tetrahedron Lett. 1998, 39, 509-512
18. Whalen, L. J.; McEvoy, K. A.; Halcomb, R. L., Synthesis and evaluation of phosphoramidate amino acid-based inhibitors of sialyltransferases. Bioorg. Med. Chem. Lett. 2003, 13 (2), 301-4.
19. Müller, B.; Schaub, C.; Schmidt, R. R., Efficient sialyltransferase inhibitors based on transition-state analogues of the sialyl donor. Angew. Chem. Int. Ed. 1998, 37, 2893-7.
20. Amann, F.; Schaub, C.; Müller, B.; Schmidt R. R., New potent sialyltransferase iInhibitors-synthesis of donor and of transition-state analogues of sialyl donor CMP-Neu5Ac. Chem. Eur. J. 1998, 4, 1106-115.
21. Schworer, R.; Schmidt, R. R., Efficient sialyltransferase inhibitors based on glycosides of N-acetylglucosamine. J. Am. Chem. Soc. 2002, 124 (8), 1632-7.
22. Sun, H. B.; Yang, J. S.; Amaral, K. E.; Horenstein, B. A., Synthesis of a new transition-state analog of the sialyl donor. Inhibition of sialyltransferases. Tetrahedron Lett. 2001, 42, 2451-3.
23. Kajihara, Y.; Kodama, H.; Wakabayashi, T.; Sato, K.; Hashimoto, H., Characterization of inhibitory activities and binding mode of synthetic 6'-modified methyl N-acetyl-β-lactosaminide toward rat liver CMP-D-Neu5Ac: D-galactoside-(2→6)-α-D-sialyltransferase. Carbohydr. Res. 1993, 247, 179-93.
24. Wu, C. Y.; Hsu, C. C.; Chen, S. T.; Tsai, Y. C., Soyasaponin I, a potent and specific sialyltransferase inhibitor. BBRC 2001, 284 (2), 466-9.
25. Chang, K. H.; Lee, L.; Chen, J.; Li, W. S., Lithocholic acid analogues, new and potent α-2,3-sialyltransferase inhibitors. Chem. Commun. 2006, (6), 629-31.
26. Chen, J. Y.; Tang, Y. A.; Huang, S. M.; Juan, H. F.; Wu, L. W.; Sun, Y. C.; Wang, S. C.; Wu, K. W.; Balraj, G.; Chang, T. T.; Li, W. S.; Cheng, H. C.; Wang, Y. C., A novel sialyltransferase inhibitor suppresses FAK/paxillin signaling and cancer angiogenesis and metastasis pathways. Cancer Res. 2011, 71 (2), 473-83.
27. Chiang, C. H.; Wang, C. H.; Chang, H. C.; More, S. V.; Li, W. S.; Hung, W. C., A novel sialyltransferase inhibitor AL10 suppresses invasion and metastasis of lung cancer cells by inhibiting integrin-mediated signaling. J. Cell. Physiol. 2010, 223 (2), 492-9.
28. Harburn, J. J.; Loftus, G. C.; Marples, B. A. Synthesis of novel steroidal inhibitors of HIV-1 protease. Tetrahedron. 1998, 54, 11907-24.
29. 鍾鎮宇，「立體化學與藥物活性探討:類石膽酸衍生物與唾液酸轉移酶抑制劑」，國立臺灣師範大學，碩士論文，民國100年。
30. Bise, R.; Kanade, T.; Yin, Z.; Huh, S. I., Automatic cell tracking applied to analysis of cell migration in wound healing assay. Conf. Proc. IEEE Eng. Med. Biol. Soc. 2011, 2011, 6174-9.
31. Wang, P. H., Altered glycosylation in cancer: sialic acids and sialyltransferases. J. Cancer Mol. 2005, 1 (2), 73-81.
32. Weijers, C. A.; Franssen, M. C.; Visser, G. M., Glycosyltransferase-catalyzed synthesis of bioactive oligosaccharides. Biotechnol. Adv. 2008, 26, 436–56.