Natural Coumarins Galbanic Acid and Auraptene Improved the Efficacy of Alkeran on Human Osteosarcoma Cells by Targeting ABC Transporters

Osteosarcoma is a severe bone malignancy, and current chemotherapeutic strategies often struggle to effectively halt disease progression. Galbanic acid (GBA) and auraptene (AUR) are natural sesquiterpene coumarins known for their diverse pharmacological activities. This study is the first to evaluate the ability of GBA and AUR to enhance Alkeran-induced toxicity in osteosarcoma cells. GBA and AUR were isolated from Ferula szowitsiana, and the viability and apoptosis of osteosarcoma cells were assessed following treatments with GBA, AUR, and Alkeran-alone and in combination. An efflux assay was conducted to determine the functional interactions of AUR and GBA with ABC transporters, and molecular docking and dynamics simulations were performed to explore their potential interactions. Single treatment of cells with each agent did not induce significant toxicity: however, combination treatments of GBA or AUR with Alkeran significantly (p < 0.0001) reduced cell viability. Synergistic interaction was strong for both coumarins and Alkeran, supported by flow cytometry detection of apoptosis and ABC transporter activity. Molecular docking and dynamics simulations demonstrated favorable and stable interactions of coumarins with ABC transporters. In conclusion, this study provides strong support that GBA and AUR enhanced Alkeran efficacy in osteosarcoma cells by targeting ABC transporters.