环状 RNA-CCT2 通过稳定 PTBP1 mRNA 激活 Wnt/β-catenin 信号通路促进肝癌发展。

Circ-CCT2 Activates Wnt/β-catenin Signaling to Facilitate Hepatoblastoma Development by Stabilizing PTBP1 mRNA.

机构信息

Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan Province, P.R. China.

出版信息

Cell Mol Gastroenterol Hepatol. 2024;17(2):175-197. doi: 10.1016/j.jcmgh.2023.10.004. Epub 2023 Oct 20.

DOI:10.1016/j.jcmgh.2023.10.004

PMID:37866478

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10758885/

Abstract

BACKGROUND & AIMS: Circ-CCT2 (hsa_circ_0000418) is a novel circular RNA that stems from the CCT2 gene. However, the expression of circ-CCT2 and its roles in hepatoblastoma are unknown. Our study aims to study the circ-CCT2 roles in hepatoblastoma development.

METHODS

Hepatoblastoma specimens were collected for examining the expression of circ-CCT2, TAF15, and PTBP1. CCK-8 and colony formation assays were applied for cell proliferation analysis. Migratory and invasive capacities were evaluated through wound healing and Transwell assays. The interaction between circ-CCT2, TAF15, and PTBP1 was validated by fluorescence in situ hybridization, RNA pull-down, and RNA immunoprecipitation. SKL2001 was used as an agonist of the Wnt/β-catenin pathway. A subcutaneous mouse model of hepatoblastoma was established for examining the function of circ-CCT2 in hepatoblastoma in vivo.

RESULTS

Circ-CCT2 was significantly up-regulated in hepatoblastoma. Overexpression of circ-CCT2 activated Wnt/β-catenin signaling and promoted hepatoblastoma progression, whereas knockdown of circ-CCT2 exerted opposite effects. Moreover, both TAF15 and PTBP1 were up-regulated in hepatoblastoma tissues and cells. TAF15 was positively correlated with the expression of circ-CCT2 and PTBP1 in hepatoblastoma. Furthermore, circ-CCT2 recruited and up-regulated TAF15 protein to stabilize PTBP1 mRNA and trigger Wnt/β-catenin signaling in hepatoblastoma. Overexpression of TAF15 or PTBP1 reversed knockdown of circ-CCT2-mediated suppression of hepatoblastoma progression. SKL2001-mediated activation of Wnt/β-catenin signaling reversed the anti-tumor effects of silencing of circ-CCT2, TAF15, or PTBP1.

CONCLUSIONS

Circ-CCT2 stabilizes PTBP1 mRNA and activates Wnt/β-catenin signaling through recruiting and up-regulating TAF15 protein, thus promoting hepatoblastoma progression. Our findings deepen the understanding of hepatoblastoma pathogenesis and suggest potential therapeutic targets.

摘要

背景与目的

Circ-CCT2（hsa_circ_0000418）是一种新型环状 RNA，源于 CCT2 基因。然而，circ-CCT2 的表达及其在肝母细胞瘤中的作用尚不清楚。本研究旨在探讨 circ-CCT2 在肝母细胞瘤发生发展中的作用。

方法

收集肝母细胞瘤标本，检测 circ-CCT2、TAF15 和 PTBP1 的表达。应用 CCK-8 法和集落形成实验检测细胞增殖情况。通过划痕愈合实验和 Transwell 实验评估细胞迁移和侵袭能力。通过荧光原位杂交、RNA 下拉和 RNA 免疫沉淀验证 circ-CCT2、TAF15 和 PTBP1 之间的相互作用。使用 SKL2001 作为 Wnt/β-catenin 通路的激动剂。建立皮下荷瘤小鼠模型，检测 circ-CCT2 在体内对肝母细胞瘤的作用。

结果

Circ-CCT2 在肝母细胞瘤中显著上调。过表达 circ-CCT2 激活 Wnt/β-catenin 信号通路，促进肝母细胞瘤进展，而敲低 circ-CCT2 则产生相反的效果。此外，TAF15 和 PTBP1 在肝母细胞瘤组织和细胞中均上调。TAF15 与肝母细胞瘤中 circ-CCT2 和 PTBP1 的表达呈正相关。此外，circ-CCT2 募集并上调 TAF15 蛋白，稳定 PTBP1 mRNA，并在肝母细胞瘤中触发 Wnt/β-catenin 信号通路。过表达 TAF15 或 PTBP1 可逆转敲低 circ-CCT2 介导的肝母细胞瘤进展抑制作用。SKL2001 介导的 Wnt/β-catenin 信号通路激活逆转了沉默 circ-CCT2、TAF15 或 PTBP1 的抗肿瘤作用。