促癌基因CAPRIN-1在转录因子调控下可生成环状RNA（circRNA），环状RNA靶向microRNA调控恶性肿瘤的生物学行为。本项目在我们从肝细胞癌临床小样本及肝癌细胞株得到的前期实验发现，以及生物信息学分析结果提示的基础上，拟运用双荧光素酶报告基因、ChIP、circRIP、RIP、小动物活体成像等技术，在细胞学、动物模型、临床样本三个层次，逐步验证转录因子c-Myc与CAPRIN-1结合，启动其转录并产生circRNA_100790，它靶向结合miR-199a-5p促进肝细胞癌增殖和侵袭转移。从而揭示c-Myc通过非编码RNA实现促癌作用的新机理，以及CAPRIN-1/circRNA_100790/miR-199a-5p轴及其所调控的下游靶基因与细胞信号传导促进肝癌进展的新机制。为将来以新型治疗载体靶向非编码RNA，阻断肝细胞癌增殖和转移，改善患者预后，提供理论依据和科学证据。

Under the regulation of specific transcription factors, the oncogene CAPRIN-1 forms multiple circle RNAs (circRNAs)，which regulate the biological behaviors of malignant tumor cells by targeting microRNAs. Based on our preliminary experimental discoveries gotten from clinical hepatocellular carcinoma (HCC) tissue in small size and human HCC cell lines, as well as bioinformatics analysis for these preliminary results, the current project aims to prove our scientific hypothesis: Following a binding with the transcription factor of c-Myc at its promoter region, CAPRIN-1 will initiate its transcription and form circRNA_100790, which subsequently facilitate the proliferation and metastasis abilities of HCC cells by targeting miR-199a-5p. In practice, multi-techniques including ChIP (chromatin immunoprecipitation assay), circRIP (circRNA binding protein immunoprecipitation), RIP (RNA binding protein immunoprecipitation), and in vivo fluorescence imaging in small animal, will be applied in independent experiments on cytology, animal models and clinical HCC specimens. The findings achieved from the present study are supposed to elucidate a novel carcinogenic role of c-Myc via a regulation on non-coding RNAs, as well as to reveal new molecular mechanisms of the proliferation and metastasis of HCC cells promoted by the axis of c-Myc-mediated CAPRIN-1-derived circRNA_100790 targeting miR-199a-5p and its downstream targeting genes and the interacted signaling pathways. Moreover, it may provide us with new clues and experimental evidences to improve the prognosis of HCC patients by blocking HCC recurrence and metastasis via applying new therapeutic carriers targeting non-coding RNAs.