C/EBPβ 3’UTR RNA可独立存在于真核细胞中并维持细胞正常生理活动和代谢。本组前期研究表明该3’UTR RNA 的肿瘤抑制功能与其3'端的A/U富集序列有关。为研究这段序列是如何发挥肿瘤抑制功能的，我们利用载体构建、RNA体外转录与标记、qPCR、western blot、ChIP、Co-IP、MS、LSCM、FCM、细胞筛选、蛋白纯化、磷酸化分析、酶活性分析、细胞周期同步化等方法对转染C/EBPβ 3’UTR A/U富集RNA片段的肝癌细胞进行分析，探索该RNA片段诱导和活化Caspase 3、剪切全长PKCε生成截短的 tPKCε、诱导和维持CK18高度磷酸化和导致肝癌细胞周期阻滞于G2/M期的分子机制和信号传导过程；并通过人肝癌组织裸鼠移植和尾静脉注射A/U富集RNA片段，证实A/U富集RNA片段在体内也发挥肿瘤抑制作用，为抑癌核酸元件的肿瘤治疗奠定理论基础和提供动物证据。

C/EBPβ 3’UTR RNA can be independently in eukaryotic cell, and plays a vital role in cell normal physiological activities and metabolism. Recent research results of our group on tumor suppression of this 3’UTR RNA showed that its function was correlated to A/U-rich RNA fragment near to 3' terminus. To uncover how this A/U-rich RNA fragment functions as a tumor suppressive element, technologies, such as vector construction, RNA transfection and labeling, quantitative real-time PCR (qPCR), western blot, chromatin immunoprecipitation assay (ChIP), co-immunoprecipitation assay (Co-IP), mass spectrometry analysis (MS), laser scanning confocal microscopy (LSCM), flow cytometry (FCM), stable transfection cell screening, protein purification, phosphorylation analysis, PKCε protein kinase activity analysis, and cell cycle synchronization, will be explored to uncover these mechanisms and signal transduction processes: how this A/U-rich RNA fragment induces and activates Caspase 3, and how the activated Caspase 3 cleaves the whole PKCε into truncated PKCε (tPKCε, molecular weight is about 54 KD ), and then how tPKCε induces and maintains CK18 phosphorylation high and, as a result, to arrest cell cycle period at G2/M phase in hepatocellar carcinoma cells transfected with C/EBPβ 3’UTR A/U-rich RNA fragment. Moreover, human fresh hepatocarcinoma tissue is implanted in the nude mouse subcutaneously, and then the A/U-rich RNA fragment is injected into the transplanted nude mouse through caudal vein to verify the fact that C/EBPβ 3’UTR A/U-rich RNA fragment also functions as a tumor suppressive element in vivo. By this project, it establishes a theoretical basis and applies the animal evidence for tumor therapy with tumor suppressive element of nucleic acid.