3rd TAGRA

Osteosarcoma is a highly aggressive malignancy with limited therapeutic advancements, often characterized by overexpression of murine double minute 2 (MDM2) and functional suppression of p53. Diosmin, a citrus-derived flavonoid, exhibits broad pharmacological properties, yet its molecular role in MDM2-p53 regulation remains unexplored. This study investigates the anti-cancer potential of diosmin in osteosarcoma via modulation of the MDM2-p53 signaling axis. Human SJSA-1 osteosarcoma cells were treated with diosmin and assessed for viability, apoptosis (Annexin V/Propidium iodide (PI)), and cell cycle dynamics via flow cytometry. Western blot analysis was used to evaluate the expression of MDM2, p53, and caspase-3. Mechanistic validation employed ZVAD (a caspase inhibitor), MG132 (a proteasome inhibitor), and MDM2 siRNA. MDM2 ubiquitination was examined in vitro. Molecular docking and 100 ns molecular dynamics simulations assessed diosmin-MDM2 interactions. Diosmin induced dose-dependent cytotoxicity (IC₅₀ = 27.91 μM), G2-M arrest, and apoptosis. It suppressed MDM2, stabilized p53, and activated caspase-3, effects reversed by ZVAD and potentiated by MG132. MDM2 knockdown mimicked diosmin's effect and co-treatment showed no additive effect, indicating a shared pathway. Diosmin enhanced MDM2 ubiquitination, and showed favorable MDM2 binding affinity (−8.6 kcal/mol) and complex stability. Diosmin effectively disrupts the MDM2-p53 axis, inducing apoptotic cell death and tumor suppression in osteosarcoma. These findings highlight diosmin as a promising natural candidate for MDM2-targeted cancer therapy.