一个功能未知的环状RNA circ-0072088调控肺腺癌恶性进展的机制研究

Combining the analysis of our previous microarray data with the RNA-seq, we identified circ-0072088 as a novel circular RNA( circRNA ) ,which is highly over-expressed in human lung adenocarcinoma tissues. Further expression level validation of this circRNA was performed by real-time RT-PCR and we found that circ-0072088 is upregulated in lung adenocarcinoma. Also，the expression level of circ-0072088 is positively correlated the pathological TNM stage and differentiation, and negatively correlated with the long-term survival time of patients significantly. SiRNA-mediated silence of circ-0072088 significantly suppressed the malignant capacity of proliferation, migration, and invasion, also significantly arrested cell cycle at the G1 stage and induced apoptosis. Bioinformatics analysis and previous experiments indicated that circ-0072088 could regulate PIK3C2A expression by competive binding miR-509. We therefore hypothesized that circ-0072088 could regulate PIK3C2A expression to promote lung adenocarcinoma progression by acting as sponge of miR-509. The current project aims to assess the relationship between circ-0072088 expression level and lung adenocarcinoma malignant progression both in vivo and in vitro in over-expression/knockdown manner. Secondly, the mechanism of competing endogenous RNA between circ-0072088, miR-509, and PIK3C2A will be deeply validated by the experiments of RIP and dual-luciferase reporter gene system. Finally, the correlation between circ-0072088/miR-509/PIK3C2A ceRNA pathway and lung adenocarcinoma progression will be further validated in samples of clinical lung adenocarcinoma patients. There is no report about function and mechanism of circular RNA in lung adenocarcinoma, our study offers a new therapeutic target for the diagnosis and treatment of lung adenocarcinoma.

circ-0072088（简称CI）是前期通过高通量芯片及测序分析筛选获得的一条差异高表达于肺腺癌、功能未知的环状RNA。验证显示CI高表达与肺腺癌分期及分化相关，且表达越高预后越差。沉默CI能抑制肺腺癌细胞株增殖及侵袭等恶性行为。生物信息学分析及预实验发现CI能吸附miR-509上调促癌基因PIK3C2A表达。故提出CI通过竞争性内源RNA（ceRNA）机制吸附miR-509上调PIK3C2A表达而促进肺腺癌恶性进展的科学假说。本项目拟临床评价CI与肺腺癌恶性进展关系，采取过表达/沉默策略，体内外实验证实CI可促进肺腺癌恶性进展；同时结合萤光素酶报告基因、RIP等技术，设计拯救实验，阐明CI竞争性结合miR-509上调PIK3C2A表达形成ceRNA网络的分子机制，并临床评价其与肺腺癌恶性进展的相关性。有关环状RNA在肺腺癌中的功能机制未见具体报道，本研究可为其防治提供新理论及新靶标。

circ-0072088（简称CI）是前期通过高通量芯片及测序分析筛选获得的一条差异高表达于肺腺癌、功能未知的环状RNA。验证显示CI高表达与肺腺癌分期及分化相关，且表达越高预后越差。沉默CI能抑制肺腺癌细胞株增殖及侵袭等恶性行为。生物信息学分析及预实验发现CI能吸附miR-1254上调促癌基因IMPDH1表达。本项目临床评价CI与肺腺癌恶性进展关系，采取过表达/沉默策略，体内外实验证实CI可促进肺腺癌恶性进展；同时结合萤光素酶报告基因、RIP等技术，设计拯救实验，阐明CI竞争性结合miR-1254上调IMPDH1表达形成竞争性内源RNA（ceRNA）网络的分子机制，并临床评价其与肺腺癌恶性进展的相关性，证实了CI通过竞争性内源RNA机制吸附miR-1254上调IMPDH1表达而促进肺腺癌恶性进展。有关环状RNA在肺腺癌中研究不多，且circ-0072088的功能机制未见具体报道，本研究可为其防治提供新理论及新靶标。