环状RNA circPDLIM5编码多肽PDLIM5-311aa促进肝癌生长和转移的作用及其分子机制

目前已鉴定的具有蛋白编码功能的circRNA很少，且缺乏合适的信息学预测方法；而参与肝癌发生发展的蛋白编码circRNA仍未知。我们运用全基因组IRES谱数据以及神经网络算法预测和筛选得到了一个潜在的蛋白编码circRNA库；进一步综合运用定点突变、荧光报告系统、免疫学和质谱技术在肝癌中鉴定了一个蛋白编码circRNA——circPDLIM5，其编码了一个多肽PDLIM5-311aa。功能研究显示敲低PDLIM5-311aa的表达能显著抑制肝癌细胞的生长和转移。本项目以此基础拟开展：进一步运用功能获得性实验通过体内外模型验证PDLIM5-311aa对肝癌生长和转移的调控作用；鉴定PDLIM5-311aa的结合蛋白及其上下游调控通路，阐明其促进细胞生长和转移的分子机理；最后通过肝癌复发动物模型和临床验证揭示circPDLIM5/PDLIM5-311aa在肝癌预后评估及治疗中的潜在应用价值。

To date, the identification of protein-coding circRNA remains rare and the bioinformatics prediction approach of protein-coding circRNA is lacking. Moreover, whether protein-coding circRNA participates in the carcinogenesis and progression of hepatocellular carcinoma (HCC) is not yet reported. In the pilot study, we have predicted a set of protein-coding circRNAs by a reported deep learning-based framework using genome-wide profiling data of internal ribosome entry site (IRES). We further identified an 311-amino-acid peptide (PDLIM5-311aa) encoded by circRNA circPDLIM5 via site-specific mutagenesis assay, fluorescent protein reporter assay, immunological and mass-spectrometric technique assay. Functional analysis revealed that knockdown of PDLIM5-311aa significantly suppressed the growth and metastasis of HCC cells. With these findings as background, we plan: 1. to further verify the regulatory effect of PDLIM5-311aa on growth and metastasis of HCC using gain-of-function assay with in vitro analyses and in vivo models; 2. To investigate the binding proteins as well as the upstream and downstream signaling pathways of PDLIM5-311aa and further clarify the mechanism underlying the regulation of PDLIM5-311aa in HCC growth and metastasis; 3. to uncover the prognostic and therapeutic value of PDLIM5-311aa by clinical investigation of human HCC specimens and recurrent mouse model.