Department of Hepatobiliary Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, Jiangsu 210008, P.R. China.
Department of General Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Clinical College of Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210008, P.R. China.
Int J Oncol. 2023 Aug;63(2). doi: 10.3892/ijo.2023.5539. Epub 2023 Jun 23.
β‑Klotho (KLB) is a vital element of the fibroblast growth factor (FGF) receptor complex and acts as a co‑receptor to facilitate the binding of FGF19 and FGF21 to the FGFRs on the target cells. The present study aimed to determine the contribution of FGF21‑KLB signaling to hepatocellular carcinoma (HCC) metastasis. KLB expression was measured in HCC tissues and cell lines using western blot and reverse transcription‑quantitative PCR. Furthermore, the proliferation, apoptosis and metastasis capacity of KLB‑knockdown Huh7 cells (human HCC cell line) were assessed by Cell Counting Kit‑8 assay, 5‑ethynyl‑2'‑deoxyuridine assay, flow cytometry, wound‑healing assay and Transwell assay. Enrichment analysis was used to explore the underlying regulatory mechanisms of KLB. The metastasis potential of human HCC cells in the context of FGF21 with or without KLB inhibition was determined and . Acetylated modification of KLB was determined using a co‑immunoprecipitation assay. The results indicated a significant upregulation of KLB in HCC tissues compared with the corresponding normal tissues. In addition, KLB expression was closely associated with HCC metastasis. Migration and invasion assays revealed that KLB knockdown promoted the metastatic capability of HCC cells. Gene set variation analysis and subsequent mechanistic investigations revealed that KLB is the upstream regulatory factor of β‑catenin signaling. Furthermore, FGF21 was indicated to suppress HCC metastasis by inhibiting β‑catenin signaling‑driven epithelial‑mesenchymal transition (EMT), while KLB knockdown and simultaneous FGF21 overexpression promoted HCC cell motility. Histone deacetylase 3 (HDAC3) was further characterized as the potential deacetylase for KLB. Furthermore, the results revealed that HDAC3 inhibitor‑mediated acetylated modification led to KLB inactivation, resulting in the blockade of FGF21‑KLB signaling, which further triggered the expression of EMT induction‑related genes in Huh7 cells. In conclusion, the present study demonstrated that aberrant acetylated modification of KLB inhibited FGF21‑KLB signaling, thereby promoting β‑catenin signaling‑driven EMT and HCC metastasis.
β-klotho (KLB) 是成纤维细胞生长因子 (FGF) 受体复合物的重要组成部分，作为辅助受体促进 FGF19 和 FGF21 与靶细胞上的 FGFR 结合。本研究旨在确定 FGF21-KLB 信号对肝细胞癌 (HCC) 转移的贡献。使用 Western blot 和逆转录-定量 PCR 测量 HCC 组织和细胞系中的 KLB 表达。此外，通过细胞计数试剂盒-8 测定、5-乙炔基-2'-脱氧尿苷测定、流式细胞术、划痕愈合测定和 Transwell 测定评估 KLB 敲低 Huh7 细胞（人 HCC 细胞系）的增殖、凋亡和转移能力。富集分析用于探索 KLB 的潜在调节机制。在有或没有 FGF21 抑制的情况下，确定人 HCC 细胞在 FGF21 中的转移潜力。使用共免疫沉淀测定确定 KLB 的乙酰化修饰。结果表明，与相应的正常组织相比，KLB 在 HCC 组织中显著上调。此外，KLB 表达与 HCC 转移密切相关。迁移和侵袭测定表明，KLB 敲低促进了 HCC 细胞的转移能力。基因集变异分析和随后的机制研究表明，KLB 是 β-连环蛋白信号的上游调节因子。此外，FGF21 通过抑制 β-连环蛋白信号驱动的上皮-间充质转化 (EMT) 抑制 HCC 转移，而 KLB 敲低和同时 FGF21 过表达促进 HCC 细胞迁移。组蛋白去乙酰化酶 3 (HDAC3) 被进一步表征为 KLB 的潜在去乙酰化酶。此外，结果表明，HDAC3 抑制剂介导的乙酰化修饰导致 KLB 失活，从而阻断 FGF21-KLB 信号，进而触发 Huh7 细胞中 EMT 诱导相关基因的表达。综上所述，本研究表明，KLB 的异常乙酰化修饰抑制了 FGF21-KLB 信号，从而促进了 β-连环蛋白信号驱动的 EMT 和 HCC 转移。
