以含醛建構單元實現便利且多元組裝的多功能蛋白質降解靶向嵌合體

Abstract

蛋白質降解靶向嵌合體(proteolysis-targeting chimeras, PROTACs)是一類新興的治療策略，能選擇性誘導蛋白降解，具有廣泛潛力，但其開發受限於分子量大、細胞通透性不足以及對連接子特性的高度依賴。為解決這些問題，我們建立了多樣化且便利的化學策略，能由醛類構件快速組裝不同的 PROTAC。第一種策略利用 Wittig 反應，在溫和條件下生成含丙烯醯胺的 PROTAC。第二種策略為接續的威悌反應及環張力促進疊氮-炔烴環加成反應(strain-promoted azide-alkyne cycloaddition, SPAAC)反應，先由帶有疊氮基的醛與膦鹽生成含丙烯醯胺的共價抑制劑(targeted covalent inhibitor, TCI)，再於細胞內與帶有 DBCO 基團的片段進行 SPAAC 反應，以降低分子量提升細胞穿膜性。第三種策略則結合硝酮生成(nitrone formation)與環張力促進炔烴-硝酮環加成反應(strain-promoted azide-nitrone cycloaddition , SPANC) 反應，透過醛與羥胺生成硝酮後，再與 DBCO 基團反應，構建多功能 PROTAC，並可修飾光敏保護基團以實現光控活性。綜合而言，這些方法提供了一個高效且靈活的平台，用於合成與功能篩選具治療潛力的PROTAC。

Proteolysis-targeting chimeras (PROTACs) are an emerging therapeutic strategy that selectively induces protein degradation, with broad potential but limited by large molecular weight, poor cell permeability, and strong dependence on linker properties. To address these issues, we developed convenient and versatile chemical strategies enabling rapid assembly of diverse PROTACs from aldehyde building blocks. The first strategy uses a Wittig reaction, generating acrylamide-containing PROTACs under mild conditions. The second employs a sequential Wittig–strain-promoted azide-alkyne cycloaddition (SPAAC) approach, where aldehydes bearing azides react with phosphonium salts to yield acrylamide-functionalized targeted covalent inhibitors (TCIs), which undergo intracellular strain-promoted azide-nitrone cycloaddition (SPANC) with DBCO fragments to improve permeability. The third combines nitrone formation with SPANC, where aldehydes and hydroxylamines form nitrones that react with DBCO groups to construct multifunctional PROTACs, allowing incorporation of photocaging groups for light-controlled activity. Together, these methods establish an efficient and flexible platform for the synthesis and functional screening of PROTACs with therapeutic potential.