Yu Shanshan, Chen Ming, Jiang Kecheng, Chen Cheng, Liang Jinxiao, Zheng Jingjing, Lou Bin, Lu Jun, Zhu Xiaohua, Zhou Donghui
Department of Surgical Oncology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Department of Surgical Oncology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310052, China.
Cancer Lett. 2025 Jun 16:217879. doi: 10.1016/j.canlet.2025.217879.
Gastric cancer (GC) is one of the most common malignant tumors with high heterogeneity, and its etiology and pathogenesis are unclear. Recently, many aberrantly alternatively spliced isoforms of the receptor tyrosine kinase recepteur d'origine nantais (RON) have been shown to play vital roles in GC development. Serine/arginine protein kinase 1 (SRPK1) is widely recognized as a key splicing factor kinase that regulates various steps of alternative splicing. Recent studies on SRPK1 have focused mainly on splicing activity, but the role of SRPK1-derived circular RNAs in RON alternative splicing and GC progression is unknown. Among all SRPK1-derived circRNAs in the CircInteractome, hsa_circ_0076168 (henceforth called circSRPK1) was upregulated in GC tissues compared with adjacent normal tissues, which was often associated with adverse outcomes in GC patients. Functionally, circSRPK1 promoted the malignant phenotype of GC. Mechanistically, circSRPK1 directly interacted with heterogeneous nuclear ribonucleoprotein A2B1 (hnRNP A2B1) to promote its nuclear translocation and binding to the exonic splicing enhancer (ESE) element on RON mRNA; this regulated the alternative splicing of downstream RON mRNA, induced RONΔ160 production, and ultimately promoted GC progression. More importantly, circSRPK1 production in GC cells was regulated by a component of the exon junction complex MAGOH, which enhanced the binding of EIF4A3 to the circSRPK1 transcript. Additionally, MAGOH knockdown rescued circSRPK1-mediated RONΔ160 formation and GC malignancy. Overall, our research revealed a novel mechanism by which the MAGOH-circSRPK1-hnRNPA2B1-RONΔ160 axis regulated GC cell proliferation and metastasis, broadening the current understanding of circRNA-mediated regulation of tumor progression through aberrant alternative splicing.
胃癌(GC)是最常见的恶性肿瘤之一,具有高度异质性,其病因和发病机制尚不清楚。最近,已显示受体酪氨酸激酶原癌基因酪氨酸蛋白激酶(RON)的许多异常可变剪接异构体在胃癌发生发展中起重要作用。丝氨酸/精氨酸蛋白激酶1(SRPK1)被广泛认为是调节可变剪接各个步骤的关键剪接因子激酶。最近关于SRPK1的研究主要集中在剪接活性上,但SRPK1衍生的环状RNA在RON可变剪接和胃癌进展中的作用尚不清楚。在CircInteractome中所有SRPK1衍生的环状RNA中,与相邻正常组织相比,hsa_circ_0076168(以下称为circSRPK1)在胃癌组织中上调,这通常与胃癌患者的不良预后相关。在功能上,circSRPK1促进了胃癌的恶性表型。机制上,circSRPK1直接与异质核糖核蛋白A2B1(hnRNP A2B1)相互作用,促进其核转位并与RON mRNA上的外显子剪接增强子(ESE)元件结合;这调节了下游RON mRNA的可变剪接,诱导RONΔ160产生,并最终促进胃癌进展。更重要的是,胃癌细胞中circSRPK1的产生受外显子连接复合体MAGOH的一个组分调节,该组分增强了EIF4A3与circSRPK1转录本的结合。此外,敲低MAGOH可挽救circSRPK1介导的RONΔ160形成和胃癌恶性程度。总体而言,我们的研究揭示了一种新机制,即MAGOH-circSRPK1-hnRNPA2B1-RONΔ160轴调节胃癌细胞增殖和转移,拓宽了目前对环状RNA通过异常可变剪接介导肿瘤进展调控的理解。