Circ-CCT2 Activates Wnt/β-catenin Signaling to Facilitate Hepatoblastoma Development by Stabilizing PTBP1 mRNA,Cellular and Molecular Gastroenterology and Hepatology

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Circ-CCT2 Activates Wnt/β-catenin Signaling to Facilitate Hepatoblastoma Development by Stabilizing PTBP1 mRNA
Cellular and Molecular Gastroenterology and Hepatology ( IF 7.1 ) Pub Date : 2023-10-20 , DOI: 10.1016/j.jcmgh.2023.10.004
Qin Zhu ₁ , Yu Hu ₁ , Wei Jiang ₁ , Zheng-Lin Ou ₁ , Yuan-Bing Yao ₁ , Hong-Yan Zai ₁

Affiliation

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.

中文翻译：

Circ-CCT2 激活 Wnt/β-catenin 信号传导，通过稳定 PTBP1 mRNA 促进肝母细胞瘤的发展

背景与目标

Circ-CCT2 (hsa_circ_0000418) 是一种源自 CCT2 基因的新型环状 RNA。然而，circ-CCT2的表达及其在肝母细胞瘤中的作用尚不清楚。我们的研究旨在研究 circ-CCT2 在肝母细胞瘤发展中的作用。

方法

收集肝母细胞瘤标本检查circ-CCT2、TAF15和PTBP1的表达。 CCK-8 和集落形成测定用于细胞增殖分析。通过伤口愈合和 Transwell 测定评估迁移和侵袭能力。通过荧光原位杂交、RNA Pull-down 和 RNA 免疫沉淀验证了 circ-CCT2、TAF15 和 PTBP1 之间的相互作用。 SKL2001 用作 Wnt/β-连环蛋白途径的激动剂。建立肝母细胞瘤皮下小鼠模型，用于研究circ-CCT2在体内肝母细胞瘤中的功能。

结果

Circ-CCT2 在肝母细胞瘤中显着上调。 circ-CCT2 的过度表达激活 Wnt/β-catenin 信号传导并促进肝母细胞瘤进展，而 circ-CCT2 的敲低则产生相反的效果。此外，TAF15和PTBP1在肝母细胞瘤组织和细胞中均上调。肝母细胞瘤中TAF15与circ-CCT2、PTBP1的表达呈正相关。此外，circ-CCT2 招募并上调 TAF15 蛋白以稳定 PTBP1 mRNA 并触发肝母细胞瘤中的 Wnt/β-catenin 信号传导。 TAF15 或 PTBP1 的过表达可逆转 circ-CCT2 介导的肝母细胞瘤进展抑制的敲低。 SKL2001 介导的 Wnt/β-catenin 信号传导激活逆转了 circ-CCT2、TAF15 或 PTBP1 沉默的抗肿瘤作用。