MicroRNAs as novel elements in personalized radiotherapy

Radiotherapy (RT) is a widely used and effective non-surgical cancer treatment. However, the mechanism behind several major challenges to efficacy, such as tumor radioresistance, normal tissue toxicity, individual radiation hypersensitivity and promoted metastatic spread, are not fully understood. The involvement of microRNAs (miRNAs) in processes important for tissue radiation responses, including DNA damage repair, activation of signalling cascades or changes to the microenvironment, is being recognized. Most recently, the exchange of miRNAs between irradiated and non-irradiated cells through microvesicles was described as a new component of the cellular radiation response. The therapeutic inhibition or mimicking of miRNAs to overcome radioresistance during therapy, and the usage of miRNAs as predictive biomarkers for therapy response and prognosis, are promising applications of miRNAs in RT. However, due to the lack of in vivo or clinical studies the full potential of miRNAs for RT is difficult to estimate. In summary this contribution gives an overview about new understanding of the miRNA involvement in the radiation response and summarizes first RT-related applications.