X-ray radiation promotes the metastatic potential of tongue squamous cell carcinoma cells via modulation of biomechanical and cytoskeletal properties.

This study investigated the metastatic potential of tongue squamous cell carcinoma (TSCC) cells after X-ray irradiation as well as radiation-induced changes in the biomechanical properties and cytoskeletal structure that are relevant to metastasis. Tca-8113 TSCC cells were X-ray-irradiated at increasing doses (0, 1, 2, or 4 Gy), and 24 h later, migration was evaluated with the wound healing and transwell migration assays, while invasion was assessed with the Matrigel invasion assay. Confocal and atomic force microscopy were used to examine changes in the structure of the actin cytoskeleton and Young's modulus (cell stiffness), respectively. X-ray radiation induced dose-dependent increases in invasive and migratory potentials of cells relative to unirradiated control cells (p < 0.05). The Young's modulus of irradiated cells was decreased by radiation exposure (p < 0.05), which was accompanied by alterations in the integrity and organization of the cytoskeletal network, as evidenced by a decrease in the signal intensity of actin fibers (p < 0.05). X-ray irradiation enhanced migration and invasiveness in Tca-8113 TSCC cells by altering their biomechanical properties and the organization of the actin cytoskeleton. A biomechanics-based analysis can provide an additional platform for assessing tumor response to radiation and optimization of cancer therapies.