Design and synthesis of novel amino acid PET tracer

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K10304
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Radiation science
• Research Institution: National Center of Neurology and Psychiatry
• Principal Investigator: KATO KOICHI 国立研究開発法人国立精神・神経医療研究センター, 脳病態統合イメージングセンター, 室長 (50382198)
• Research Collaborator: TSUJI Atsushi ; KUMAMOTO Takuya
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: アミノ酸 / PET / トランスポーター / モノカルボン酸

Outline of Final Research Achievements

In this study, 11C-labeled S-methyl-α-methylcysteine (LMMCY) and S-methyl-cysteine (LMCY) were synthesized and their PET studies were carried out using small lung cell SY-tumor bearing mice. Both tracers were accumulated highly in the tumor and the uptake ratios into pancreas and liver were significantly different. The uptake of LMMCY was high in the pancreas and that of LMCY was high both in the pancreas and liver. The mechanism of different uptake of these tracers remains to be studied.
The comparison study of uptake of 11C-AIB and its analog 11C-MeAIB into tumor was performed using eight lung cancer cells. Both tracers were transported into all cells mainly through system A. In addition 11C-AIB was transported partially via system L and ASC. Therefore higher uptake of 11C-AIB was observed in all cells than 11C-MeAIB and in three cells statistically significant difference.

Free Research Field

放射性医薬品

Academic Significance and Societal Importance of the Research Achievements

アミノ酸はペプチドやタンパク質の構成要素であり、代謝を介してクエン酸回路の中間体、あるいは神経伝達物質を供給する。疾患によってペプチドやタンパク質の合成、ATP産出やシナプス化学伝達が亢進・抑制することから、アミノ酸の代謝や細胞への取り込みの変化をPETで捉えた画像は様々な疾患診断の指標になると考えられる。
本研究で検討を行った11C標識メチル-α-メチルシステインは既存のメチルシステインと比較して小細胞がんに細胞により高く集積し、膵臓/肝臓の取込み比が大きいことが明らかになった。取込み過程の違いが明らかになれば、それぞれの臓器を対象とした診断、治療への道が開けるのではないかと考えられる。