解码新型长链非编码RNA lnc-SLC6A12-1:3和lnc-SLC6A12-7:5在调节胆管癌中GAD1和SLC6A12表达方面的作用。
Decoding the role of novel long noncoding RNAs lnc-SLC6A12-1:3 and lnc-SLC6A12-7:5 in regulating the expression of GAD1 and SLC6A12 in cholangiocarcinoma.
作者信息
Arun Sharma Manjunath, Devaki Neerkaje Subrayabhat
机构信息
Department of Molecular Biology, Yuvaraja's College, University of Mysore, Mysuru, Karnataka 570005, India.
出版信息
Comput Biol Chem. 2025 Jun 20;119:108562. doi: 10.1016/j.compbiolchem.2025.108562.
Cholangiocarcinoma (CCA) is an aggressive bile duct malignancy with a poor prognosis and limited treatment options. Recent studies highlight the role of metabolic and signalling pathways in tumour progression and resistance, including neurotransmitter-related pathways like gamma-aminobutyric acid (GABA). Key GABA-associated genes, such as Solute Carrier Family 6 Member 12 (SLC6A12), a GABA transporter and Glutamate Decarboxylase 1 (GAD1) involved in GABA synthesis, are implicated in cancer but remain poorly understood in CCA. This study aims to identify novel long non-coding RNAs (lncRNAs) specifically associated with cholangiocarcinoma (CCA) and to explore their potential mechanisms of action. By integrating transcriptomic data and interaction prediction tools, we focus on lncRNAs that are linked to key differentially expressed metabolic genes, thereby uncovering their possible roles in the metabolic reprogramming of CCA. Using RNA-Seq data from the Sequence Read Archive (SRA), differential expression analysis identified 84 differentially expressed metabolic genes (DEMGs) associated with metabolic pathways. Gene ontology and pathway analyses using DAVID and Reactome database revealed pathway enrichment due to DEGs, while protein interaction using STRING, functionally connected SLC6A12/BGT1 and GAD1/GAD67. Two novel downregulated long non-coding RNAs (lncRNAs), lnc-SLC6A12-1:3 and lnc-SLC6A12-7:5, were identified based on expression correlations and genomic proximity to SLC6A12 and GAD1 genes. Interaction predictions using IntaRNA and lncTAR tools suggested lncRNA-mRNA interactions between the lncRNAs and mRNAs (SLC6A12 and GAD1). Transcription factor (TF) enrichment analysis using the CiiiDER tool and RNA-protein interaction predictions with the catRAPID tool revealed lnc-SLC6A12-1:3 functions as a regulatory scaffold, influencing the transcription of SLC6A12 and GAD1 by recruiting TFs such as IRF1, THAP1, FOSL1, and NR4A1. Whereas lnc-SLC6A12-7:5 did not show strong binding to TFs. In Ideal conditions, lnc-SLC6A12-1:3 enhances SLC6A12 expression by promoting IRF1 and FOSL1 activity but antagonises THAP1 and NR4A1, leading to the checked expression of GAD1. These interactions highlight a complex regulatory network where lnc-SLC6A12-1:3 and lnc-SLC6A12-7:5 differentially modulate transcription factor activity, balancing the expression of these key genes in CCA. For the first time, this in silico study reveals that two novel long non-coding RNAs, lnc-SLC6A12-1:3 and lnc-SLC6A12-7:5, regulate the expression of SLC6A12 and GAD1 through cis and trans binding interactions, respectively. Based on these interactions, we hypothesise that these lncRNAs may contribute to the modulation of the GABAergic pathway, which plays a crucial role in fulfilling the high energy demands of cholangiocarcinoma cells. Further experimental validation and investigation into the regulation of SLC6A12 and GAD1 are required to gain deeper insights into CCA pathogenesis and to identify potential therapeutic targets.
胆管癌(CCA)是一种侵袭性胆管恶性肿瘤,预后较差且治疗选择有限。最近的研究强调了代谢和信号通路在肿瘤进展和耐药性中的作用,包括与神经递质相关的通路,如γ-氨基丁酸(GABA)。关键的GABA相关基因,如溶质载体家族6成员12(SLC6A12),一种GABA转运体,以及参与GABA合成的谷氨酸脱羧酶1(GAD1),与癌症有关,但在CCA中仍了解甚少。本研究旨在鉴定与胆管癌(CCA)特异性相关的新型长链非编码RNA(lncRNA),并探讨其潜在的作用机制。通过整合转录组数据和相互作用预测工具,我们聚焦于与关键差异表达代谢基因相关的lncRNA,从而揭示它们在CCA代谢重编程中的可能作用。使用来自序列读取存档(SRA)的RNA-Seq数据,差异表达分析鉴定出84个与代谢途径相关的差异表达代谢基因(DEMG)。使用DAVID和Reactome数据库进行基因本体和通路分析,揭示了由于DEG导致的通路富集,而使用STRING进行蛋白质相互作用分析,在功能上连接了SLC6A12/BGT1和GAD1/GAD67。基于表达相关性以及与SLC6A12和GAD1基因的基因组邻近性,鉴定出两个新的下调长链非编码RNA(lncRNA),即lnc-SLC6A12-1:3和lnc-SLC6A12-7:5。使用IntaRNA和lncTAR工具进行的相互作用预测表明,lncRNA与mRNA(SLC6A12和GAD1)之间存在lncRNA-mRNA相互作用。使用CiiiDER工具进行转录因子(TF)富集分析以及使用catRAPID工具进行RNA-蛋白质相互作用预测表明,lnc-SLC6A12-1:3作为一种调节支架,通过招募IRF1、THAP1、FOSL1和NR4A1等TF来影响SLC6A12和GAD1的转录。而lnc-SLC6A12-7:5与TF没有显示出强结合。在理想条件下,lnc-SLC6A12-1:3通过促进IRF1和FOSL1的活性来增强SLC6A12的表达,但拮抗THAP1和NR4A1,从而导致GAD1的表达受到抑制。这些相互作用突出了一个复杂的调节网络,其中lnc-SLC6A12-1:3和lnc-SLC6A12-7:5差异调节转录因子活性,平衡CCA中这些关键基因的表达。这项计算机模拟研究首次揭示,两个新的长链非编码RNA,lnc-SLC6A12-1:3和lnc-SLC6A12-7:5,分别通过顺式和反式结合相互作用调节SLC6A12和GAD1的表达。基于这些相互作用,我们推测这些lncRNA可能有助于调节GABA能通路,而该通路在满足胆管癌细胞的高能量需求中起关键作用。需要进一步的实验验证以及对SLC6A12和GAD1调节的研究,以更深入地了解CCA的发病机制并确定潜在的治疗靶点。