Design, Synthesis, and Evaluation of Novel Oxime-Ether Derivatives of Spinosyn A as ASS1 Activators and Antitumor Agents

Argininosuccinate synthase (ASS1) plays a significant role in cancer pathogenesis and progression, making it a promising novel therapeutic target for anticancer drug development. However, pharmacological studies targeting ASS1 remain largely underexplored. The natural product spinosyn A (SPA) has exhibited potent cytotoxic effects against multiple tumor cell lines. Our previous studies identified that SPA's antitumor mechanism primarily involves ASS1 activation, which established spinosyn derivatives as the only reported class of ASS1 activators to date. Building on this foundation, we designed and synthesized a series of novel 17-oxime ether-substituted spinosyn derivatives. Among these, compound 10f demonstrated substantially enhanced ASS1 activation and superior cytotoxicity against various cancer cells compared to SPA. Mechanistic investigation revealed that 10f induces tumor cell apoptosis by modulating the AMPK/mTOR signaling pathway through ASS1 activation. In vivo studies confirmed that 10f possesses significantly improved antitriple-negative breast cancer efficacy compared to SPA, highlighting its substantial therapeutic potential.