Phosphoproteomic profiling reveals signaling pathways modulated by Annona muricata leaf extract in oral adenosquamous carcinoma cells

Phosphorylation driven dysregulation of intracellular signaling networks is a central feature of cancer initiation, progression, and therapeutic resistance. Although Annona muricata leaf extracts have demonstrated anticancer activity across multiple experimental models, the underlying molecular mechanisms particularly at the level of phosphorylation dependent signaling remain poorly understood. In this study, we employed a tandem mass tag TMT-based quantitative phosphoproteomic approach to systematically characterize signaling alterations induced by methanolic Annona muricataleaf extract (AME) in oral squamous cell carcinoma (OSCC) CAL-27 cells. Functional assays revealed that AME significantly inhibited cell proliferation, migration, and clonogenic survival. Global phosphoproteomic profiling identified 6,362 phosphopeptides corresponding to 1,964 unique phosphorylation sites across nearly 7,000 phosphoproteins. AME treatment induced widespread, time-dependent hypophosphorylation, indicating a coordinated suppression of oncogenic signaling networks. Pathway and network analyses revealed marked inhibition of signaling pathways associated with key oncogenic kinases, including cyclin-dependent kinases (CDKs), mitogen-activated protein kinases (MAPKs), and signaling modules linked to EGFR and mTOR pathways. Kinase-substrate enrichment and kinome mapping further demonstrated reduced inferred activity of CDK and MAPK driven signaling, accompanied by suppression of cell cycle progression, mitosis, and checkpoint regulation. Collectively, these findings demonstrate that AME induces systems-level remodeling of phosphorylation dependent signaling networks, enforcing a growth-restrictive cellular state in OSCC cells. This study highlights quantitative phosphoproteomics as a powerful strategy for dissecting natural product mediated regulation of oncogenic signaling and provides mechanistic insight into the anticancer potential of Annona muricata.