miR-4725-3p靶向NRAS调控PI3K/Akt/p53通路介导肺腺癌细胞低剂量放射超敏感性的研究

低剂量放射超敏感性（HRS）对肿瘤放疗有重要意义，机理不明。一般认为与关键因子p53及PI3K/Akt、Mdm2和ROS调控的增殖、凋亡有关。我们发现XWLC-05与A549细胞放射后存活率有差异，细胞放射敏感性和PI3K/Akt通路也不同，与miR-4725-3p表达有关，因此猜测miR-4725-3p可能调控PI3K/Akt通路影响HRS。利用克隆形成、流式细胞术、蛋白印迹、定量PCR、双荧光素酶、免疫细胞化学、移植瘤动物实验等等，对比研究XWLC-05与A549两种细胞的HRS，并对PI3K/Akt通路活化、NRAS、MDM2、p53、ROS、凋亡和DNA损伤修复等研究，深入探讨从上游miR-4725-3p-NRAS-PI3K/Akt信号通路到中间Mdm2-p53功能和下游ROS分子等的一条完整信号通路调节肺腺癌细胞HRS的发生机制，以期揭示肺腺癌细胞的HRS放射生物效应及相关机制。

Low Dose Hyper-radiosensitivity (HRS) is important for tumor radiotherapy. The mechanism is unclear. It was considered to be related to cell proliferation and apoptosis which were regulated by the key factor p53 and PI3K/Akt, Mdm2, ROS. In primary study, we found the survival rates of XWLC-05 and A549 cells were different after conventional dose or low-dose radiation, as well as the cell radiosensitivity and PI3K/Akt pathway. These differences were related to the expression of miR-4725-3p. Therefore, we hypothesized that miR-4725-3p might regulate the PI3K/Akt pathway to affect HRS. Cloning formation, flow cytometry, western blot, quantitative PCR, double luciferase, immunocytochemistry, and animal transplanted tumor were used to compare the HRS of XWLC-05 and A549 cells, and to present the mechanisms of HRS regulated by the integrated signal pathway, which were composed of miR-4725-3p-NRAS-PI3K/Akt to Mdm2-p53 and to ROS in lung cancer cells. Through this research implementation, it will provide an important scientific evidence for low dose fractionated radiotherapy for lung cancer.