Dammarenediol II enhances etoposide-induced apoptosis by targeting O-GlcNAc transferase and Akt/GSK3β/mTOR signaling in liver cancer

Combining chemotherapy with chemosensitizing agents is a common strategy to enhance Anticancer efficacy while mitigating treatment-related side effects. This study investigated the potential of dammarenediol II (DM2), a ginsenoside precursor, to enhance the Anticancer effects of etoposide by downregulating O-linked β-N-acetylglucosamine modification (O-GlcNAcylation) and modulating the Akt signaling pathway in HepG2 human liver Cancer cells. The effect of DM2 on O-GlcNAcylation regulation was analyzed using Pharmaco-Net, an artificial intelligence-driven drug screening platform and further validated using O-GlcNAc transferase (OGT) activity assay. DM2 cotreatment enhanced etoposide's Anticancer efficacy, which was quantitatively evaluated by viability, Annexin V binding, membrane integrity, and Caspase-3/7 activity assays in HepG2 cells. Results showed that DM2 reduced O-GlcNAc levels by directly interacting with OGT, as confirmed through Pharmaco-Net. Cotreatment with 40 μm DM2 and 20 μm etoposide produced synergistic Anticancer effects, lowering etoposide's IC₅₀ for cell viability by 2.29-fold and its EC₅₀ for Caspase-3/7 activity by 3.64-fold. Mechanistically, DM2 dose-dependently suppressed Akt/GSK3β/mTOR signaling. Using the Akt Activator SC79, additional experiments confirmed that Akt signaling acts downstream of O-GlcNAcylation regulated by etoposide and DM2. These effects were also observed in multiple human liver Cancer cell lines, as well as in A549 lung and Caco-2 colorectal Cancer cells. This supports the broader Anticancer and Akt-inhibitory potential of DM2. This study is the first to demonstrate that DM2 enhances Anticancer synergy by suppressing O-GlcNAcylation and Akt signaling, highlighting its potential as a novel chemotherapy Adjuvant.