Exosomal MicroRNA-151a-3p Improves the Sensitivity to Radiotherapy via the Interaction between p53 and Histone Deacetylase 5

Background: Tumor-derived exosomal microRNAs are key elements of the cell-cell communications response to lots of stimuli. However, various functions of the exosome in tumor suppression by radiotherapy (RT) are not clearly understood. Our study showed a previously unknown interaction of p53 and histone deacetylase 5 (HDAC5) by radiation exposure in hepatocellular carcinoma (HCC). Methods: Using serial ultracentrifugation methods, radiation and non-radiation exosomes were purified to investigate the radioresistance of miRNA151a-3p. Radiation doses were treated in 2gy and 4gy using radiation equipment X-RAD 320 to observe the expression of HDAC5 and p53 in hepatic cancer cells. Exosomal miRNA bioinformatics analysis was conducted to find a variation in the miRNA configuration inside Exosome after radiation exposure.Results: HDAC5 and p53 interacted by exposure to radiation, which increased exosome release and altered microRNAs' composition within exosomes. Also, we have described the intercommunication occurring between irradiated and untreated cells via exosomal microRNAs that affect tumor proliferation. In particular, the expression of exosomal microR151a-3p was markedly reduced by radiation treatment. We confirmed that inhibition of exosomal microR151a-3p promotes suppression of non-irradiated cancer cells, thereby increasing RT sensitivity. Conclusion: our present findings demonstrated HDAC5 is a key component of the p53-mediated release of exosomes resulting in tumor suppression through exosomal microRNA-151a-3p in response to radiation. Finally, we highlight the important role of exosomal microRNA 151a-3p as a biomarker in enhancing RT sensitivity.