RM2 ベースの GRPR リガンドにおける Gln-Trp 部位の変化の影響に関する研究
Sebastian Fischer1, Lena Koller1, Sandra Dominelli1
1TUM School of Natural Sciences, Department of Chemistry, Chair of Pharmaceutical Radiochemistry, Technical University of Munich, 85748, Garching, Germany.
EJNMMI research
|September 1, 2025
まとめ
非自然なアミノ酸でガストリン放出ペプチド受容体 (GRPR) リガンドRM2を修正すると,その安定性と薬理学的な性質に影響する. α- メチル- L- トリプトファンアナログは,体内の安定性を改善し,GRPRを標的としたイメージングと治療の可能性を高めました.
科学分野:
- 放射薬化学
- 分子イメージング
- 腫瘍学
背景:
- ガストリン放出ペプチド受容体 (GRPR) のリガンドは,臨床前および臨床がん研究において極めて重要です.
- RM2アンタゴニストはよく研究されたGRPRリガンドである.
- RM2における非自然なアミノ酸置換の調査は,そのin vivoの安定性と薬理学プロフィールを改善することを目的としています.
研究 の 目的:
- 不自然なアミノ酸 (ホモセリン,β-3-ベンゾチエニル) アラニン,α-メチル-L-トリプトファン) が,RM2ペプチドのGln-Trp部位に与える影響を評価する.
- RM2 アナログ性能に対する異なるケラター (DOTA,NOTA,NODAGA) の影響を評価する.
- 様々な放射性金属 (Ga,Cu,Lu) を用いて新しいRM2誘導体の臨床前効果を評価する.
主な方法:
- 非自然なアミノ酸とケラターによるRM2ペプチド誘導体の合成と放射性マーキング
- 68 Ga,64 Cu,および177 Luを用いた臨床前評価
- GRPRの親和性,脂性,in vivoの安定性,および腫瘍モデルにおける生物分布の評価
主要な成果:
- RM2の誘導体は,ナノモラー範囲でGRPRの親和性を示した.
- α- メチル- L- トリプトファンアナログ ([177Lu]Lu- AMTG) は,他のアナログと比較して,体内の安定性が著しく高いことを示した.
- [68 Ga-AMTGと[68 Ga-RM2は高腫瘍吸収を示したが, [68 Ga-[Hse7]RM2と[68 Ga-[Bta8]RM2は腫瘍と臓の吸収が低い.
- ルラベルのAMTGとRM2は,注射後24時間で高い腫瘍保持を示した.
結論:
- 不自然なアミノ酸で Gln- Trp 部位の置換は RM2 の薬理学に影響を及ぼします.
- α- メチル- L- トリプトファンの置換は,in vivoの安定性を高め,薬理学的特性を改善します.
- ホモセリンとβ- ((3-ベンゾチエニル) アラニンの置換は,改善された腫瘍と背景の比率でイメージング特性を最適化する可能性がある.
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