LncRNA-UCA1介导AKT/mTOR通路对乏氧诱导的非小细胞肺癌放射抵抗的影响及机制研究

Hypoxia is one of the main causes of radioresistance in NSCLC. Its previous studies focused on the effects of signal pathways on DNA damage and angiogenesis. However, there is little research on the effect of lncRNA on hypoxia-induced radioresistance in tumor cells. We have confirmed that UCA1 activates AKT / mTOR pathway to induce poor prognosis of NSCLC and found that UCA1 promoter region has HIF-1α binding site, UCA1 expression in hypoxia-induced NSCLC cells was significantly increased; after silencing of the UCA1 mRNA expression, the survival rate of hypoxia-induced NSCLC cells significantly decreased, the apoptosis rate was significantly increased. Therefore, we hypothesized that UCA1 affects hypoxia-induced radioresistance in NSCLC and may be associated with AKT/mTOR pathway, but the specific mechanism remains to be elucidated. Based on the previous research, this subject will focus on the main line of "Hypoxia-HIF-1α-UCA1-AKT/mTOR-radioresistance", which is elucidated UCA1 in hypoxia-induced NSCLC radioresistance from cell, animal and molecular level by cell interference, clonal formation, animal model and so on in order to improve the efficacy of radiotherapy in NSCLC.

乏氧是造成NSCLC放射抵抗的主要原因之一，其既往机制研究主要集中在信号通路对DNA损伤和血管新生影响的探讨。但关于lncRNA对乏氧诱导的肿瘤细胞放射抵抗影响的研究较少。我们前期证实UCA1激活AKT/mTOR通路引起NSCLC的预后差，并发现UCA1启动子区存在HIF-1α的结合位点，UCA1在乏氧诱导的NSCLC细胞中的表达明显升高；干扰UCA1 mRNA表达后，乏氧诱导的NSCLC细胞的存活率明显下降，凋亡率明显升高。因此，我们推测UCA1影响乏氧诱导的NSCLC放射抵抗且可能和AKT/mTOR通路相关，但具体机制有待阐明。本课题在前期研究基础上，拟围绕“Hypoxia-HIF-1α-UCA1-AKT/mTOR-放射抵抗”这一主线，通过细胞干扰、克隆形成、动物模型等方法，从细胞、动物及分子水平阐明UCA1在乏氧诱导的NSCLC放射抵抗中的作用机制，为提高NSCLC放疗疗效提供参考。

乏氧是造成NSCLC放射抵抗的主要原因之一，本项目采用医院放疗科西门子直线加速器照射细胞株和动物，采用Real-time qPCR检测UCA1的表达；荧光素酶报告基因检测HIF-1α直接调控UCA1的表达；以 CCK-8法、克隆形成等方法检测射线对肺癌细胞的增殖能力变化；以流式细胞术检测细胞周期和细胞凋亡；Transwell检测细胞侵袭转移；western blot检测蛋白表达等。当前研究主要发现UCA1在乏氧诱导的非小细胞肺癌细胞中的表达明显高于常氧状态下的表达；UCA1启动子中存在HIF-1α的结合位点，采用siRNA干扰UCA1表达后，在相同剂量的射线照射下，乏氧状态下肺癌细胞的存活率明显下降；随着照射剂量的增高，乏氧状态的肺癌细胞的存活率逐渐下降。流式细胞术检测细胞凋亡显示，si-UCA1 组细胞的凋亡明显增加。UCA1介导AKT/mTOR通路影响乏氧诱导的NSCLC放射抵抗。通过本项目的研究，有利于加深UCA1对乏氧诱导的NSCLC的放射抵抗的影响的认识，这将有利于深入理解乏氧诱导的放射抵抗的机制，进而为改善放疗疗效和生存质量提供思路和依据。现以共同通讯作者身份发表SCI论文1篇，审稿中SCI论文1篇，已标注受本项目资助。