20‐Acetylsinularolide B (ASB) From <i>Lobophytum crassum</i> Exhibits Anticancer Activity In Vitro Through IGF1R/PI3K/AKT/mTOR Pathway

As lung cancer remains the leading cause of cancer-related deaths worldwide, the development of novel therapeutic drugs is essential. 20-Acetylsinularolide B (ASB) is a diterpene isolated from marine soft coral Lobophytum crassum. Our previous studies demonstrated that ASB exhibits growth-inhibitory effects on non-small cell lung cancer (NSCLC) cells. This study employed network pharmacology to predict ASB's potential targets in NSCLC treatment. The predicted target was validated using the cellular thermal shift assay (CETSA). In vitro anticancer activity was assessed through MTT and crystal violet assays for proliferation, along with Western blotting, cell cycle and apoptosis analysis, mitochondrial membrane potential, reactive oxygen species (ROS) levels, and nuclear morphology evaluation. Migration and invasion were evaluated using wound healing and Transwell assays. The results showed that ASB significantly arrests the cell cycle of H1299 cells at the G₂/M phase by modulating the IGF1R/PI3K/AKT/mTOR signaling pathway, thereby inhibiting cell mitosis. Simultaneously, ASB promoted intracellular ROS production, reduced mitochondrial membrane potential, and ultimately induced cell apoptosis. In addition, ASB significantly inhibited the colony formation, migration, and invasion abilities of H1299 cells, which are closely associated with the function of the IGF1R target. These findings highlight the significant potential of ASB as a lead anticancer compound for NSCLC therapy.