Ovatodiolide overcomes cisplatin resistance in head and neck cancer by disrupting a novel oncogenic signature and cancer-associated fibroblast activation.

BACKGROUND/PURPOSE: Malignant head and neck squamous cell carcinoma (HNSCC) is an aggressive cancer with complex tumor microenvironment interactions. We aimed to identify key molecular drivers and therapeutic targets using bioinformatics approaches and examine their associations with cancer-associated fibroblasts (CAF). MATERIALS AND METHODS: We analyzed three HNSCC transcriptomic datasets using bioinformatics. Protein-protein interaction networks were created using STRING, and pathway enrichment was also performed. The clinical relevance and CAF association of genes were evaluated using the TCGA HNSCC cohort and TIMER 2.0. Molecular docking predicted ovatodiolide binding to target proteins. Bioinformatics findings were validated in HNSCC cell lines and normal fibroblasts (WS1) by assessing cell viability, tumor spheroid formation, and CAF transformation through viability assays, qPCR, and Western blot. A mouse model of cisplatin resistance was used to test ovatodiolide's therapeutic effect. RESULTS: Our bioinformatics identified a nine-gene oncogenic network in HNSCC enriched in inflammatory and profibrotic pathways. A core three-gene SIS oncogenic signature (SERPINE1, INHBA, SPP1) was identified. High SIS expression correlated with poor survival and increased CAF infiltration. Docking predicted favorable binding of ovatodiolide to SERPINE1, SPP1, and INHBA. CAF-conditioned medium enhanced the stemness and chemoresistance of HNSCC cells, promoting SIS signature and stemness markers. Ovatodiolide suppressed oncogenic properties and CAF activation, decreasing SIS and CAF markers. In a mouse model, ovatodiolide overcame cisplatin resistance by reducing the SIS signature. CONCLUSION: The SIS signature contributes to HNSCC progression, stemness, and drug resistance by facilitating CAF generation. Ovatodiolide disrupts this signature and inhibits CAF transformation.