Theranostics 2017; 7(6):1524-1530. doi:10.7150/thno.19371 This issue Cite

Short Research Communication

Synthesis of 5-[18F]Fluoro-α-methyl Tryptophan: New Trp Based PET Agents

Benjamin C. Giglio1*, Haiyang Fei2*, Mengzhe Wang1, Hui Wang1, Liu He1, Huijuan Feng1, Zhanhong Wu1, Hongjian Lu2✉, Zibo Li1✉

1. Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
2. Institute of Chemistry and BioMedical Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
* These authors contributed equally to the research work.

Citation:
Giglio BC, Fei H, Wang M, Wang H, He L, Feng H, Wu Z, Lu H, Li Z. Synthesis of 5-[18F]Fluoro-α-methyl Tryptophan: New Trp Based PET Agents. Theranostics 2017; 7(6):1524-1530. doi:10.7150/thno.19371. https://www.thno.org/v07p1524.htm
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Abstract

Graphic abstract

Indoleamine 2,3-dioxygenase (IDO1) plays a special role in the biology of various cancer types, because it breaks down the essential amino acid tryptophan for immune cell activation. Upregulation of IDO1 significantly correlates with the number of various T cell types in tumor tissues in melanoma and other cancers, suggesting that IDO expression is linked with effective and ineffective ('exhausted') immune response in cancer. Based on the reported IDO inhibitors (α-Methylated and indole-N-methylated tryptophan (Trp)), here we report the synthesis of potential IDO1 imaging agents through direct introduction of 18F into the tryptophan aromatic ring. Overall, the resulting PET agents could be obtained in high radiochemical purity (>97%) with labeling yield ranges from 4.2-14.9% decay corrected yield. Using Trp as the model compound, our results also demonstrate that 18F could be directly introduced to the Trp backbone at the 4, 5, 6, and 7 position. Moreover, our initial imaging study suggests that 5-[18F]F-L-α-methyl tryptophan (5-[18F]F-AMT) holds great potential for cancer imaging. The success of this approach will provide researchers easy access to a library of Trp/Trp-derivative based PET agents for biomedical research, including potential IDO1 targeted imaging.

Keywords: 18F radiolabeling, Positron emission tomography (PET), Tryptophan (Trp), Indoleamine 2, 3-dioxygenase (IDO1), Immunotherapy.


Citation styles

APA
Giglio, B.C., Fei, H., Wang, M., Wang, H., He, L., Feng, H., Wu, Z., Lu, H., Li, Z. (2017). Synthesis of 5-[18F]Fluoro-α-methyl Tryptophan: New Trp Based PET Agents. Theranostics, 7(6), 1524-1530. https://doi.org/10.7150/thno.19371.

ACS
Giglio, B.C.; Fei, H.; Wang, M.; Wang, H.; He, L.; Feng, H.; Wu, Z.; Lu, H.; Li, Z. Synthesis of 5-[18F]Fluoro-α-methyl Tryptophan: New Trp Based PET Agents. Theranostics 2017, 7 (6), 1524-1530. DOI: 10.7150/thno.19371.

NLM
Giglio BC, Fei H, Wang M, Wang H, He L, Feng H, Wu Z, Lu H, Li Z. Synthesis of 5-[18F]Fluoro-α-methyl Tryptophan: New Trp Based PET Agents. Theranostics 2017; 7(6):1524-1530. doi:10.7150/thno.19371. https://www.thno.org/v07p1524.htm

CSE
Giglio BC, Fei H, Wang M, Wang H, He L, Feng H, Wu Z, Lu H, Li Z. 2017. Synthesis of 5-[18F]Fluoro-α-methyl Tryptophan: New Trp Based PET Agents. Theranostics. 7(6):1524-1530.

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