Thermo-responsive nano-hydrogel-based delivery of Saikosaponin a to enhance anti-PD-1 therapy in osteosarcoma.

Objective: This study aimed to identify key targets of Saikosaponin A (SSA) in treating osteosarcoma (OS) using network pharmacology and transcriptomics, and to develop a temperature-sensitive hydrogel nanocomplex delivering SSA in combination with the PD-1 inhibitor pembrolizumab to enhance anti-tumor effects.

Methods: Through network pharmacology and transcriptomic analysis, 23 co-regulated genes were identified, leading to the construction of a prognostic risk model containing four core genes. Molecular dynamics simulations were employed to explore the binding interaction between SSA and the key target FASN. The Gel@PLGA@SSA@FA was synthesized and characterized. Its cytotoxicity and therapeutic effects were evaluated in OS cell lines, both alone and in combination with pembrolizumab.

Results: FASN was validated as a poor prognostic marker in OS, and molecular simulations confirmed that SSA can effectively bind to FASN. Gel@PLGA@SSA@FA significantly downregulated FASN and CD279 mRNA expression, especially when combined with pembrolizumab. In vitro release studies demonstrated sustained drug release under tumor-mimicking conditions. Functional assays revealed that the combination treatment markedly suppressed OS cell proliferation and migration, induced apoptosis, and exhibited low toxicity toward normal cells.

Conclusion: The combination of Gel@PLGA@SSA@FA with pembrolizumab shows strong synergistic anti-tumor effects, offering a promising and biocompatible strategy for enhanced OS therapy.