Mir384, Inhibited By Nf-Kb, Enhances Radiosensitivity In Human Non-Small Cell Lung Cancer Via Modulating Dna Damage Response And Repair Signaling

Radiotherapy achieved remarkable effects in the treatment of non-small cell lung cancer (NSCLC). However, radioresistance is still the major obstacles that decrease the outcomes of NSCLC patients. DNA damage response and repair signaling have been demonstrated greatly involving in modulating radiosensitivity and prognosis of patients with NSCLC. This study aims at identifying novel DDR signaling regulators and potential target for enhancing radiosensitivity of NSCLC. Lentivirus-based infection and CRISPR/Cas9 editing technology were applied for overexpression and depletion of microRNA-384 (miR-384), respectively. Clonogenic assay and g-H2AX immunofluorescence staining were performed to analyze the effects of miR-384 on radiosensitivity of NSCLC cells. FACS was applied to detect cell death. Luciferase reporter assay, western blotting, and qRT-PCR were applied to prove ATM, Ku70, and Ku80 to be direct targets of miR-384. Luciferase reporter assay, Ch-IP, and qRT-PCR were applied to demonstrate that NF-kB inhibits miR-384 directly. In the current study, we found that the expression of miR-384 positively correlated with radiosensitivity of NSCLC cells. Ectopic overexpression of miR-384 radiosensitized NSCLC cells by inhibiting DNA damage repair and increasing apoptosis, while knockout miR-384 led to radiation resistance with enhanced DNA damage repair and decreased apoptosis. Further investigation revealed that ATM, Ku70, and Ku80 were direct targets of miR-384. Moreover, we identified miR-384 to be a direct downstream gene of NF-kB, and NF-kB inhibits the expression of miR-384. In the current study, miR-384 was proved to enhance radiosensitivity via NF-kB/MIR384/ATM feedback loop and inhibiting Ku70 and Ku80 to impair DDR signaling in NSCLC. Here, we specifically highlighted a novel mechanism that microRNA involved in modulating DDR signaling and radiosensitivity of NSCLC. This study evidenced that miR-384 could be a novel therapeutic target for NSCLC.