背景:胰腺癌(PC)是一种恶性程度极高的肿瘤,生存率低。缺乏PC的有效生物标志物和治疗靶标。环状RNA(circularRNAs,circRNAs)在癌症中的作用已经在各种研究中被探索,然而,需要更多的工作来了解特定circRNAs的功能作用。在这项研究中,我们探讨了circ_0035435(称为circCGNL1)在PC中的具体作用和机制。
方法:进行qRT-PCR分析以检测cccGNL1表达,表明circCGNL1在PC细胞和组织中低表达。在体外和体内检查了circCGNL1在PC进展中的功能。circCGNL1相互作用蛋白通过进行RNA下拉来鉴定,免疫共沉淀,GST-下拉,和双荧光素酶报告基因测定。
结果:过表达ccGNL1通过促进细胞凋亡抑制PC增殖。CircCGNL1与磷酸酶nudix水解酶4(NUDT4)相互作用,以促进组蛋白去乙酰化酶4(HDAC4)去磷酸化和随后的HDAC4核易位。核内HDAC4介导的RUNX家族转录因子2(RUNX2)去乙酰化,从而加速RUNX2降解。转录因子,RUNX2抑制胍基乙酸N-甲基转移酶(GAMT)表达。进一步验证GAMT通过AMPK-AKT-Bad信号通路诱导PC细胞凋亡。
结论:我们发现circCGNL1可以与NUDT4相互作用以增强NUDT4依赖性HDAC4去磷酸化,随后激活HDAC4-RUNX2-GAMT介导的细胞凋亡以抑制PC细胞生长。这些发现为PC提供了新的治疗靶点。
Pancreatic cancer (PC) is an extremely malignant tumor with low survival rate. Effective biomarkers and therapeutic targets for PC are lacking. The roles of circular RNAs (circRNAs) in cancers have been explored in various studies, however more work is needed to understand the functional roles of specific circRNAs. In this study, we explore the specific role and mechanism of circ_0035435 (termed circCGNL1) in PC.
qRT-PCR analysis was performed to detect circCGNL1 expression, indicating circCGNL1 had low expression in PC cells and tissues. The function of circCGNL1 in PC progression was examined both in vitro and in vivo. circCGNL1-interacting proteins were identified by performing RNA pulldown, co-immunoprecipitation, GST-pulldown, and dual-luciferase reporter assays.
Overexpressing circCGNL1 inhibited PC proliferation via promoting apoptosis. CircCGNL1 interacted with phosphatase nudix hydrolase 4 (NUDT4) to promote histone deacetylase 4 (HDAC4) dephosphorylation and subsequent HDAC4 nuclear translocation. Intranuclear HDAC4 mediated RUNX Family Transcription Factor 2 (RUNX2) deacetylation and thereby accelerating RUNX2 degradation. The transcription factor, RUNX2, inhibited guanidinoacetate N-methyltransferase (GAMT) expression. GAMT was further verified to induce PC cell apoptosis via AMPK-AKT-Bad signaling pathway.
We discovered that circCGNL1 can interact with NUDT4 to enhance NUDT4-dependent HDAC4 dephosphorylation, subsequently activating HDAC4-RUNX2-GAMT-mediated apoptosis to suppress PC cell growth. These findings suggest new therapeutic targets for PC.