Spheroid-based 3D Cell Cultures Enable Personalized Therapy Testing and Drug Discovery in Head and Neck Cancer

Background/Aim: Chemo-radiation currently serves as first-line therapy of advanced and recurrent head and neck cancer, while new chemotherapy regimens are emerging. However, response rates to any treatment are difficult to predict and underlie broad variation. This study shows the development of a standardized, high-throughput in vitro assay to assess patients' individual response to therapy regimens as a future tool for personalized tumor therapy. Materials and Methods: Viability and proliferation analyses after chemo +/- radiation treatment of single spheroids (low adhesion plates/Hanging Drop (HD)) were generated from head and neck squamous cell carcinoma (HNSCC) cell lines and primary human cells from fresh tumor specimens. Results: All cell lines showed reliable growth in all cell culture methods. The spheroids showed significant delay of growth and/or necrosis compared to control groups when exposed to current standard chemotherapeutic regimens. Single 3D spheroids ready for therapy susceptibility testing could be generated from actual tumor specimens after enzymatic and mechanical separation. Conclusion: In its current form, this single spheroid-based in vitro assay was able to test individual therapy susceptibility to current standard therapy regimens or, potentially, for testing new targeted drugs in HNSCC treatment. With recent discoveries regarding tumor heterogeneity and individual mutation status, a reliable assay is a prerequisite for personalized therapy in head and neck cancer.