Study of tumor invasiveness by super resolution fluorescence microscopy in cells irradiated with FLASH and conventional radiotherapy

The effects of FLASH Radiotherapy (FLASH RT) on tumor invasiveness remain poorly understood, particularly at the molecular level of cell adhesion. In this study, murine and rabbit-derived tumor cell lines were irradiated using FLASH RT (≥ 40 Gy/s) and Conventional Radiotherapy (CONV RT) (∼ 2 Gy/min). Cells were fixed and labeled with fluorophore-conjugated antibodies targeting N-Cadherin and Integrin αvβ3, then imaged using STORM super resolution fluorescence microscopy. Structural changes in the distribution, clustering, and density of these adhesion proteins were quantitatively analyzed. FLASH RT induced distinct alterations in adhesion protein organization compared to CONV RT, suggesting differences in how tumor cells regulate cell-ECM interactions after exposure. These findings highlight the importance of investigating dose rate-dependent changes in cell adhesion and high-resolution visualization of adhesion molecule remodeling, to better understand how FLASH RT may influence tumor invasiveness.