低氧环境下circRNA-103698作为miR-204海绵对口腔鳞状细胞癌迁移侵袭行为的机制性研究

Hypoxia could induce the dysregulation of miRNAs to promote the tumor metastasis, and the expression of miRNAs are also regulated by endogenous circular RNA (circRNA), which are termed competing endogenous RNAs (ceRNAs). Our previous study showed that hypoxia significantly increased the expression of circ-103698 and RAB22A in oral squamous cell carcinoma(OSCC) through circRNA and mRNA Microarrays. The base-pair complementary bindings were observed between circ-103698-miR-204 and miR-204-RAB22A via bioinformatics. However, it is unclear whether hypoxia-induced dysregulation of circ-103698-miR-204-RAB22A promote OSCC metastasis. Therefore, in this study, the many experiments, including cellular functions and clinical specimens, were performed to explore the construction method of circ-103698 overexpression vector, evaluated the interactions between circ-103698, miR-204 and RAB22A, and analyse hypoxia-induced circRNA-103698 whether functions as a miR-204 sponge to stimulate OSCC metastasis via RAB22A pathways. This project may provide new clues for hypoxia-induced the dysregulation of miRNAs and clinical targeted therapy.

低氧环境可引起miRNAs的异常表达从而促进肿瘤的转移，circRNA作为一类特殊的环状ceRNA可调控miRNAs的表达。我们前期采用circRNA和mRNA表达谱芯片发现低氧环境下circ-103698和RAB22A在口腔鳞状细胞癌（OSCC）中的表达显著升高，生物信息学显示miR-204与二者之间存在良好的碱基互补关系，但低氧环境下circ-103698-miR-204-RAB22A的异常调控是否参与OSCC的转移？本课题拟通过细胞学实验及临床标本检测来探讨circ-103698过表达载体的构建方法；评价circ-103698、miR-204和RAB22A之间的相互作用关系；分析低氧环境下circ-103698作为miR-204海绵通过调控RAB22A信号通路对OSCC细胞表型及迁移侵袭的影响，为深入阐明OSCC瘤内低氧环境下miRNAs的失调机制及临床靶向治疗提供新的思路。

研究背景：目前已有研究发现circRNA的异常表达可参与多种肿瘤的发生及进展，然而目前有关低氧微环境下circRNA与口腔鳞状细胞癌（OSCC）之间的相关性研究甚少。.研究内容：基于 circRNA microarray筛选获得差异表达的circ-PKD2(circRNA-103698)，检测circ-PKD2在OSCC及正常组织中的表达差异及其与低氧微环境的关系，分析circ-PKD2异常表达与OSCC患者不同临床病理的相关性。细胞学实验检测常氧及低氧微环境下circ-PKD2异常表达对OSCC细胞增殖、凋亡、迁移及侵袭行为的调控以及circ-PKD2对miR-204-3p的海绵吸附效应及相关细胞功能学研究。.研究结果：与正常组织相比，circ-PKD2在OSCC组织中的表达显著下调，并且与OSCC患者的组织分型、TNM分期及淋巴结转移密切相关。成功构建circ-PKD2过表达载体及其干扰RNA，发现低氧微环境下circ-PKD2过表达能够抑制OSCC细胞的增殖活性及迁移能力，同时促进细胞凋亡的发生。此外，体内及体内实验进一步发现circ-PKD2过表达能够显著抑制OSCC细胞的增殖活性及迁移侵袭行为，同时可诱导细胞周期的阻滞及凋亡的发生；抑制circ-PKD2后对OSCC细胞的功能学效应与circ-PKD2过表达相反。此外，证实了circ-PKD2对miR-204-3p的海绵吸附效应以及miR-204-3p与APC2之间的靶向关系，并且进一步发现了circ-PKD2能够介导miR-204-3p/APC2轴激活多条相关信号通路对OSCC不同生物学行为的调控作用。.科学意义：本项目首次发现低氧微环境下circ-PKD2的异常表达能够调控OSCC细胞的增殖、凋亡及侵袭特性，同时阐明circ-PKD2可介导miR-204-3p/APC2轴调控OSCC新的病理机制，为OSCC早期诊断标记物及新靶点的筛选提供了新的理论依据。