Fig. 5
From: Molecular mechanisms of tumor resistance to radiotherapy
The role of exosomes in cancer radiotherapy resistance. Radiation-induced paracrine effects mediated by exosomes and their contents (e.g., exosomal proteins and non-coding RNAs) affect radiotherapy efficacy via different pathways. Radiation also promotes the polarization of M1 tumor-associated macrophages to the M2 phenotype, which suppresses the anti-tumor immune response, whereas M1 macrophage–derived exosomes repolarize the M2 phenotype to the M1 phenotype, reshaping the tumor immunosuppressive microenvironment and improving the efficacy of radiation therapy. M1: M1-type tumor-associated macrophages (anti-tumor), M2: M2-type tumor-associated macrophages (pro-tumor), miRNAs: micro-RNAs, lncRNAs: long non-coding RNAs, circRNA: circular RNA, mRNA: messenger RNA