Scutellarin mediates cell cycle arrest and apoptosis in liver cancer through a novel circSRBD1/miR-2682-5p/ESR1 ceRNA axis

Scutellarin (SCU) is a natural flavonoid compound exhibiting anti-tumor activity. This study aimed to elucidate the molecular mechanism underlying SCU’s therapeutic effects in liver cancer. An integrated approach combining network pharmacology and transcriptomic analysis was employed to identify SCU-related targets, followed by the identification of core targets through protein–protein interaction (PPI) network construction and topological analysis using MCC and MCODE algorithms. A circular RNA (circRNA)-mediated competing endogenous RNA (ceRNA) regulatory network was constructed by integrating data from databases including miRWALK and circBANK with whole-transcriptome sequencing. Molecular interactions were experimentally validated using Western blotting, dual-luciferase reporter assays, and RNA immunoprecipitation (RIP). In Huh7 and HepG2 cells, overexpression and knockdown models of key RNAs were established to evaluate their functional roles, with cell proliferation, cell cycle distribution, and apoptosis assessed via CCK-8, colony formation, and flow cytometry assays. To investigate in vivo anti-tumor efficacy and associated mechanisms, a subcutaneous xenograft tumor model was established in nude mice. Integrated network pharmacology and transcriptomic analysis identified 11 core genes significantly enriched in the estrogen signaling pathway, among which ESR1 was validated as a key target. SCU downregulated ESR1 expression in a dose-dependent manner. Mechanistically, SCU upregulated miR-2682-5p while downregulating circSRBD1. Dual-luciferase reporter assays confirmed that miR-2682-5p directly binds to the 3′UTRs of both circSRBD1 and ESR1, supporting the existence of a circSRBD1/miR-2682-5p/ESR1 ceRNA regulatory axis. Functional studies demonstrated that overexpression of circSRBD1 attenuated SCU-induced cell cycle arrest, apoptosis, and suppression of proliferation, whereas silencing circSRBD1 enhanced these effects. Furthermore, SCU and fulvestrant exhibited synergistic anti-tumor activity both in vitro and in vivo. This study identifies a novel circSRBD1/miR-2682-5p/ESR1 ceRNA regulatory axis that plays a critical role in mediating SCU’s inhibitory effects on liver cancer progression, highlighting the potential therapeutic value of combining SCU with fulvestrant. Not applicable.