Department of Hepatobiliary and Pancreatic Surgery, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
Zhejiang Provincial Key Laboratory of Pancreatic Disease, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
Hepatol Commun. 2023 Jul 24;7(8). doi: 10.1097/HC9.0000000000000204. eCollection 2023 Aug 1.
Intrahepatic cholangiocarcinoma (iCCA) is an aggressive malignancy with multiple etiologies and is largely refractory to current treatment strategies. Myeloid leukemia factor 1 (MLF1) is associated with human cancer progression. Nevertheless, the function of MLF1 in iCCA remains unknown.
We performed expression analyses of MLF1 in human iCCA. In vitro and in vivo experiments were conducted to investigate the role of MLF1 in iCCA progression. The upstream regulatory mechanism of MLF1 upregulation in iCCA was deciphered by luciferase and DNA methylation analyses.
MLF1 was significantly upregulated in clinical iCCA tissue specimens and human iCCA cell lines. MLF1 was positively correlated with KRT19 and MUC1 expression and epithelial-mesenchymal transition (EMT) gene set enrichment score in clinical iCCA. High MLF1 expression was independently associated with worse prognoses in iCCA patients after curative resection. In addition, experimental knockdown of MLF1 attenuated, while overexpression of MLF1 promoted the proliferation, invasiveness, and growth of iCCA cells in vitro and in vivo. Mechanically, MLF1 comodulated EGFR/AKT and Wnt/β-catenin signalings through regulating EGFR, AKT, WNT3, and p-GSK3β expression. Promoter CpG sites' hypermethylation-induced downregulation of miR-29c-3p contributed to MLF1 upregulation in iCCA patients. The upregulation of DNA methyltransferase (DNMT)1, 3A, and 3B downregulated miR-29c-3p by dictating promoter DNA methylation pattern. MiR-29c-3p showed therapeutic potential by targeting MLF1 in iCCA.
Our results demonstrated that hypermethylation-mediated miR-29c-3p downregulation contributes to MLF1 upregulation in iCCA, which resulted in tumor cells' proliferation and metastasis through comodulating EGFR/AKT and Wnt/β-catenin signalings.
肝内胆管癌（iCCA）是一种具有多种病因的侵袭性恶性肿瘤，对当前的治疗策略大多具有抗性。髓系白血病因子 1（MLF1）与人类癌症的进展有关。然而，MLF1 在 iCCA 中的功能仍然未知。
我们对人 iCCA 中的 MLF1 进行了表达分析。通过体外和体内实验研究了 MLF1 在 iCCA 进展中的作用。通过荧光素酶和 DNA 甲基化分析解析了 MLF1 在 iCCA 中上调的上游调控机制。
MLF1 在临床 iCCA 组织标本和人 iCCA 细胞系中显著上调。MLF1 与 KRT19 和 MUC1 的表达以及临床 iCCA 中的上皮-间充质转化（EMT）基因集富集评分呈正相关。高 MLF1 表达与根治性切除后 iCCA 患者的预后不良独立相关。此外，实验性敲低 MLF1 减弱，而过表达 MLF1 促进 iCCA 细胞在体外和体内的增殖、侵袭和生长。在机制上，MLF1 通过调节 EGFR、AKT、WNT3 和 p-GSK3β 的表达来共同调节 EGFR/AKT 和 Wnt/β-catenin 信号通路。启动子 CpG 位点的超甲基化诱导 miR-29c-3p 的下调导致 iCCA 患者 MLF1 的上调。DNA 甲基转移酶（DNMT）1、3A 和 3B 的上调通过决定启动子 DNA 甲基化模式下调 miR-29c-3p。miR-29c-3p 通过靶向 MLF1 在 iCCA 中显示出治疗潜力。
我们的研究结果表明，高甲基化介导的 miR-29c-3p 下调导致 iCCA 中 MLF1 的上调，通过共同调节 EGFR/AKT 和 Wnt/β-catenin 信号通路导致肿瘤细胞的增殖和转移。
