Gingerol acts as a potent radiosensitizer in head and neck squamous cell carcinoma.

Treatment options for advanced head and neck squamous cell carcinoma (HNSCC) are limited and often cause severe toxicity and debilitating long-term impacts. Developing effective and safer treatments is warranted. Several plant extracts have shown their effectiveness, but a comprehensive comparison between plant extracts in HNSCC has not been reported. Our aim was to investigate the effect of different plant extracts on the proliferation and viability of HNSCC cell lines. In addition, we investigated the efficacy of combining cytotoxic plant extracts with radiation. Since RT is a cornerstone in the treatment and management of HNSCC, it is desirable to enhance its efficacy through combination with cytotoxic agents that have minimal side effects. HNSCC cell lines were treated with various plant extracts at different concentrations. MTT assays were performed to identify the most potent anti-tumor plant extract. Colony-formation assays were performed to determine the radiosensitization effect. To investigate the effect on migration, transwell migration assays were performed. Annexin V staining was performed to analyze cell apoptosis. 6-gingerol resulted in the most significant dose-dependent inhibition in all cell lines compared to other plant extracts. Colony-formation assays showed a significant radiosensitizing effect when 6-gingerol was combined with radiation. In addition, the combination of 6-gingerol with radiation resulted in a significant decrease in HNSCC cell migration. Mechanistically, Annexin V staining showed that the combination of 6-gingerol and RT induces a synergistic apoptotic effect in MOC1, MOC2 and SCC9 cells compared to RT alone. In conclusion, 6-gingerol enhances the effect of radiation in HNSCC cell lines and could be a suitable candidate for combination therapy in HNSCC.