摘要Objective:Radiotherapy has achieved remarkable effects in treating non-small cell lung cancer(NSCLC).However,radioresistance remains the major obstacle to achieving good outcomes.This study aims at identifying potential targets for radiosensitizing NSCLC and elucidating the underlying mechanisms.Methods:Lentivirus-based infection and CRISPR/Cas9 technology were used to modulate the expression of microRNA-384(miR-384).Cell clonogenic formation assays and a xenograft tumor model were used to analyze radiosensitivity in NSCLC cells.Fluorescence-activated cell sorting was used to assess the cell cycle and cell death.Immunofluorescence staining,Comet assays,and homologous recombination or non-homologous end-joining I-SceI/GFP reporter assays were used to study DNA damage and repair.Western blotting and quantitative real-time polymerase chain reaction were used to identify the targets of miR-384.Chromatin immunoprecipitation and polymerase chain reaction were performed to evaluate upstream regulators of miR-384.Results:MiR-384 was downregulated in NSCLC.Overexpression of miR-384 increased the radiosensitivity of NSCLC cells in vitro and in vivo,whereas knockout of miR-384 led to radioresistance.Upregulation of miR-384 radiosensitized NSCLC cells by decreasing G2/M cell cycle arrest,inhibiting DNA damage repair,and consequently increasing cell death;miR-384 depletion had the opposite effects.Further investigation revealed that ATM,Ku70,and Ku80 were direct targets of miR-384.Moreover,miR-384 was repressed by NF-κB.Conclusions:MiR-384 is an ionizing radiation-responsive gene repressed by NF-κB.MiR-384 enhances the radiosensitivity of NSCLC cells via targeting ATM,Ku80,and Ku70,which impairs DNA damage repair.Therefore,miR-384 may serve as a novel radiosensitizer for NSCLC.