Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China.
Department of Hepatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China.
J Exp Clin Cancer Res. 2019 Oct 7;38(1):413. doi: 10.1186/s13046-019-1415-5.
CyclinD1 is crucial for cell cycling and can regulate the expression of Dicer, a crucial regulator of microRNA maturation. However, little is known on how CyclinD1 regulates Dicer and miRNA expression, and the progression of intrahepatic cholangiocarcinoma (ICC).
The expression of CyclinD1 and Dicer in non-tumor cholangiocytes, ICC cells and tissues as well as their association with clinicopathological characteristics and survival were examined. The potential mechanisms by which CyclinD1 regulates Dicer and relative miRNA expression were determined by immunoprecipitation, ChIP sequence, BSP and luciferase reporter assays following induction of CyclinD1 over-expression or silencing and Dicer silencing. The impact of CyclinD1 and/or Dicer silencing on the growth of ICC was tested in vivo.
Up-regulated CyclinD1 was associated with down-regulated Dicer expression in ICC tissues and poorer overall survival in patients with ICC. CyclinD1 interacted with the nuclear H3K9me3 and SUV39H1 and bound to the Dicer promoter to increase its CpG island methylation in ICC cells. Functionally, CyclinD1 silencing inhibited the malignancy of ICC cells, which were mitigated partially by Dicer silencing in ICC cells. Dicer silencing down-regulated miR-1914-5p and miR-541-5p expression, which targeted and promoted CyclinD1 and CDK6 expression in ICC cells.
Our findings uncover that CyclinD1 inhibits Dicer expression by chromatin modification to reduce miR-1914-5p/miR-541-5p expression, which positively-feedback enhances CyclinD1 and CDK6 expression and progression of ICC.
细胞周期蛋白 D1 对细胞周期至关重要，可调节 Dicer 的表达，Dicer 是 microRNA 成熟的关键调节因子。然而，CyclinD1 如何调节 Dicer 和 miRNA 表达以及肝内胆管癌（ICC）的进展知之甚少。
检测非肿瘤胆管细胞、ICC 细胞和组织中 CyclinD1 和 Dicer 的表达，及其与临床病理特征和生存的关系。通过免疫沉淀、ChIP 序列、BSP 和荧光素酶报告基因检测，在诱导 CyclinD1 过表达或沉默以及 Dicer 沉默后，确定 CyclinD1 调节 Dicer 和相对 miRNA 表达的潜在机制。在体内检测 CyclinD1 和/或 Dicer 沉默对 ICC 生长的影响。
ICC 组织中上调的 CyclinD1 与下调的 Dicer 表达相关，ICC 患者的总生存率较差。CyclinD1 与核 H3K9me3 和 SUV39H1 相互作用，并与 Dicer 启动子结合，增加 ICC 细胞中 CpG 岛的甲基化。功能上，CyclinD1 沉默抑制了 ICC 细胞的恶性程度，而在 ICC 细胞中沉默 Dicer 部分缓解了这种恶性程度。Dicer 沉默下调了 miR-1914-5p 和 miR-541-5p 的表达，这两种 miRNA 靶向并促进了 ICC 细胞中 CyclinD1 和 CDK6 的表达。
我们的研究结果揭示了 CyclinD1 通过染色质修饰抑制 Dicer 表达，从而降低 miR-1914-5p/miR-541-5p 的表达，正向反馈增强了 CyclinD1 和 CDK6 的表达，促进了 ICC 的进展。
