肝内胆管癌(ICC)是原发性肝癌的一种类型(原发性肝癌主要包括肝细胞癌和肝内胆管癌),其全球发病率明显上升。ICC的恶性程度远高于肝细胞癌(通常所指的肝癌),仅少数较早期的病人可通过肝切除治疗延长生存,绝大多数病人尤其是中晚期病人缺乏有效治疗方法,生存时间极短。探索ICC的发生和侵袭转移机制,对于发现新的治疗靶点,提高ICC该病治疗水平具有潜在和重要的意义。
2022年1月,我院沈锋教授团队在Journal of Hepatology(IF=30.083)发表了题目为“Circular RNA ACTN4 promotes intrahepatic cholangiocarcinoma progression by recruiting YBX1 to initiate FZD7 transcription”的研究论著。他们发现一种环状RNA(命名为circACTN4)在ICC组织中显著上调;体外和体内实验表明circACTN4高表达增强ICC的增殖和转移能力;病人ICC肿瘤内circACTN4的高表达可导致肝切除术后更高的复发转移率和更短的生存时间。机制研究表明circACTN4通过吸附miR-424-5p上调Yes相关蛋白1(YAP1)的表达,尤其是circACTN4还可通过招募Y-box结合蛋白1(YBX1)刺激Frizzled-7(FZD7)的转录。此外,ICC细胞中circACTN4过表达可增强YAP1(Hippo信号通路核心成分)和β-catenin(Wnt信号通路核心成分)之间的相互作用,表明circACTN4可同时调节两种与肿瘤侵袭转移相关的信号通路。
总之,他们的研究证实circACTN4在ICC中表达上调并通过充当miR-424-5p的分子海绵,以及通过与YBX1相互作用(激活FZD7的转录),促进ICC增殖转移,提示circACTN4可能是ICC潜在的预后标志物和新的治疗靶点。
沈锋教授团队对ICC外科和多学科治疗,以及该病的发生和侵袭转移机制进行了长期大量研究。他们建立了较为成熟的该病手术治疗体系;发表该病相关SCI论著60余篇;报道国际领先的ICC术后远期生存率;主持编写了ICC外科治疗中国专家共识;研究结果改写了国际经典的ICC的AJCC/TNM分期,并被纳入NCCN等经典国际诊治指南。以ICC临床研究为重要内容分别获得国家科技进步二等奖和上海市科技进步一等奖等。他们团队在ICC研究方面始终走在国际前列。
Fig. 1.CircACTN4 identification and its relationship with ICC prognosis.
(A,B)Heatmap and scatter-plot of differentially expressed circRNAs in 7 paired ICC and adjacent non-tumor tissues using RNA microarray analysis. (C) CircACTN4 expression in 60 paired ICC and non-tumor tissues using qRT-PCR. (D) Validation of circACTN4 expression in 6 paired ICC and non-tumor tissues using RNase R. NT, non-tumor; T, tumor. (E) Basic circACTN4 expression in 4 cell lines using qRT-PCR. (F,G) CircACTN4 localization and relative expression in subcellular fractions using FISH assay. Nuclei were stained with DAPI. Scale bar, 20 μm. (H,I) Kaplan-Meier curves of overall survival and recurrence in different circACTN4 expression groups. For (C) and (E), data are presented as means ± SDand analyzed using Student’s t test, and experiments were repeated three times. RNase R, Ribonuclease R; FISH, fluorescence in situ hybridization.
Fig. 7. CircACTN4 involves in the Wnt/Hippo signaling pathways.
(A) CircACTN4 increasedβ-catenin and p-GSK3β levels in RBE cells in western blot. (B) CircACTN4 stimulated the nucleus accumulation of β-catenin in RBE cells in western blot. (C) CircACTN4 increased Wnt/β-catenin pathway activity in RBE cells in TOP/FOP-Flash reporter assay. (D) Co-localization between YAP1 and β-catenin proteins using immunofluorescence in RBE cells. Nuclei were stained with DAPI. Scale bar, 20 μm. (E) Co-immunoprecipitation assay showed circACTN4 promoted YAP1 and β-catenin nuclear accumulation. For (A-C), data are presented as means ± SD and analyzed using Student’s t test. The experiments were repeated in triplicate.
