The Early Response After Radiation Therapy on Three-Dimensional Oral Cancer Model Using Patient-Derived Cancer-Associated Fibroblasts

Background/Objectives: Cancer-associated fibroblasts (CAFs), which are an important component of the tumor microenvironment, have been reported to have an adverse effect on conventional radiotherapy. This study aims to elucidate the effects of CAFs in boron neutron capture therapy (BNCT) using a three-dimensional (3D) oral cancer model. Methods: Three-dimensional cancer models were fabricated using patient-derived CAFs or patient-derived normal oral fibroblasts (NOFs) and a human oral squamous cell carcinoma cell line. Each 3D cancer model was performed with either a conventional X-ray treatment or BNCT and additionally analyzed histomorphologically. Results: The 3D oral cancer-CAFs model demonstrated a greater depth of cancer cell invasion than the 3D oral cancer-NOFs model. Radiation therapy for the 3D oral cancer models indicated a trend for decreasing cancer cell invasion and cell number with dose dependence in both X-ray and BNCT. In comparison with X-rays, BNCT showed a consistent increase in the number of NOFs and a significant reduction in the number of CAFs. Conclusions: BNCT for the 3D oral cancer model was shown to be effective against cancer cells and CAFs but not against NOFs, indicating its usefulness as a minimally invasive treatment for advanced cancer. Furthermore, it is indicated that the 3D oral cancer-CAFs model is a valuable tool to evaluate cancer treatment and research, particularly in high-grade malignant tumors with invasion.