Pangestu Norma Sainstika, Chueakwon Piyasiri, Talabnin Krajang, Khiaowichit Juthamas, Talabnin Chutima
School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
School of Pathology, Institute of Medicine, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
Oncol Lett. 2021 Dec;22(6):846. doi: 10.3892/ol.2021.13107. Epub 2021 Oct 21.
RING finger protein 43 () is a ubiquitin E3 ligase that negatively regulates Wnt/β-catenin signalling. Mutation, inactivation and downregulation of in cholangiocarcinoma (CCA) are associated with a less favourable prognosis. Since the functional role of RNF43 in CCA has not yet been demonstrated, the present study aimed to assess the effect of its overexpression in mediating CCA suppression via Wnt/β-catenin signalling pathway inhibition. Accordingly, was overexpressed, and various malignant phenotypic changes studied, including cell proliferation, cell migration, chemotherapeutic sensitivity and the expression of several Wnt/β-catenin target genes. Overexpression of RNF43 in the CCA cell-line KKU-213B hindered activation of Wnt/β-catenin signalling, evidenced by: i) Accumulation of β-catenin in the cytoplasmic fraction and downregulation of several known Wnt target genes at the mRNA level [, survivin (), and ()]; ii) a reduction of cell proliferation; iii) a significant decrease in KKU-213B cell migration with RNF43 overexpression via upregulation of E-cadherin (); and iv) a reduction in N-cadherin (), and . In addition, overexpression of RNF43 increased 5-fluorouracil sensitivity and downregulation of ABC transporter genes [including and (MRP1)]. The current results demonstrate a functional role for RNF43 in CCA by: i) Blocking β-catenin nuclear translocation; and ii) the subsequent downregulation of Wnt/β-catenin target genes (the latter being involved in the progression of CCA and chemotherapeutic drug susceptibility). Therefore, the present findings suggest that RNF43 could serve a tumour suppressive role in CCA.
环指蛋白43（RNF43）是一种泛素E3连接酶，对Wnt/β-连环蛋白信号通路起负调控作用。胆管癌（CCA）中RNF43的突变、失活和下调与预后较差相关。由于RNF43在CCA中的功能作用尚未得到证实，本研究旨在评估其过表达通过抑制Wnt/β-连环蛋白信号通路介导CCA抑制的作用。因此，使RNF43过表达，并研究了各种恶性表型变化，包括细胞增殖、细胞迁移、化疗敏感性以及几种Wnt/β-连环蛋白靶基因的表达。RNF43在CCA细胞系KKU-213B中的过表达阻碍了Wnt/β-连环蛋白信号通路的激活，证据如下：i）β-连环蛋白在细胞质部分的积累以及几种已知Wnt靶基因在mRNA水平的下调[、存活素（survivin）、和]；ii）细胞增殖减少；iii）通过上调E-钙黏蛋白（E-cadherin），RNF43过表达使KKU-213B细胞迁移显著减少；iv）N-钙黏蛋白（N-cadherin）、和的减少。此外，RNF43的过表达增加了5-氟尿嘧啶的敏感性，并下调了ABC转运蛋白基因[包括和（多药耐药相关蛋白1，MRP1）]。目前的结果通过以下方式证明了RNF43在CCA中的功能作用：i）阻断β-连环蛋白的核转位；ii）随后下调Wnt/β-连环蛋白靶基因（后者参与CCA的进展和化疗药物敏感性）。因此，本研究结果表明RNF43在CCA中可能起到肿瘤抑制作用。
