Interference of Ape 1 / Ref-1 enhances neutron radiosensitivity in non-small cell lung cancer 95 D cells

Non-small Cell Lung Cancer (NSCLC) is the major pathological type of lung cancer that accounts for more than 80%. Surgery, radiotherapy, and chemotherapy are the main treatment method. Following the continuous development of radiation oncology, radiotherapy has become one of the methods for NSCLC with significant curative effect. However, it also has certain limitation such as radioresistance. Investigation of the mechanism of radioresistance and the corresponding measures becomes the hotspot. This study explores the role of Ape1/Ref-1 in NSCLC radiotherapy via RNAi technology to knockdown Ape1/Ref-1 expression in NSCLC cell line 95D. RNAi technology was applied to downregulate Ape1/Ref-1 expression in 95D cells. MTT assay and colony formation assay were used to analyze 95D cell survival and colony formation ability after radiotherapy. Alkaline comet assay and γH2AX expression were adopted to investigate DNA injury, while flow cytometry was performed to detect cell apoptosis to explore the killing effect of radioactive rays on 95D cells. Under the same radiation dose, 95D cell survival rate and fraction were significantly lower, while radiosensitivity was obviously higher after pSilence APE1 transfection compared with pSilence Control (P < 0.05). Moreover, 95D cells exhibited markedly enhanced comet tail moment, increased apoptosis, and upregulated γH2AX mRNA and protein (P < 0.05). Downregulation of Ape1/Ref-1 expression elevated the radiosensitivity of 95D cells, which may be related to the inhibition of DNA repair involved by Ape1/Ref-1.