Deciphering the role of taurine-upregulated gene 1 in liver diseases: Mechanisms, clinical relevance, and emerging therapeutic opportunities

Figure 2 Taurine-upregulated gene 1 regulatory network in hepatocellular carcinoma. This diagram illustrates the complex interplay between taurine-upregulated gene 1 (TUG1) and various genes, microRNAs (miRNAs), and signaling pathways in hepatocellular carcinoma. TUG1 modulates the expression of oncogenes and tumor suppressors (e.g., mucin 1, collagen type I alpha 1, interferon induced transmembrane protein 1), influencing cellular processes like proliferation, metastasis, and apoptosis. TUG1 acts as a competitive endogenous RNA by sponging miRNAs (e.g., miR-4726-5p, miR-29c-3p), thereby regulating their target genes. Additionally, TUG1 interacts with transcription factors (e.g., triiodothyronine/thyroid hormone receptors, specificity protein 1) and epigenetic modifiers (e.g., polycomb repressive complex 2 complex) to control gene expression. Red arrows indicate activation, and T-bars indicate repression (created in BioRender). AFP: Alpha-fetoprotein; AKT2: Protein kinase B 2; AMPKβ2: AMP-activated protein kinase beta 2; AURKA: Aurora kinase A; CD47: C luster of Differentiation 47; COL1A1: Collagen type I alpha 1; CXCR4: C-X-C motif chemokine receptor 4; DLX2: Distal-less homeobox 2; E2F1: E2F transcription factor 1; EZH2: Enhancer of zeste 2 polycomb repressive complex 2 subunit; IFITM1: Interferon induced transmembrane protein 1; IGF1: Insulin like growth factor 1; JAK2: Janus kinase 2; KLF2: Krüppel-like factor 2; MUC1: Mucin 1; P21: Cyclin-dependent kinase inhibitor 1A; PD-L1: Programmed death-ligand 1; PRC2: Polycomb repressive complex 2; ROMO1: Reactive oxygen species modulator 1; RRAGD: Ras related GTP binding D; Shh: Sonic hedgehog; Siglec-15: Sialic acid-binding immunoglobulin-like lectin-15; SIX1: SIX homeobox 1; Sp1: Specificity protein 1; SRSF9: Serine and arginine rich splicing factor 9; SUZ12: Suppressor of zeste 12; T3: Triiodothyronine; TR: Thyroid hormone receptors; TUG1: Taurine-upregulated gene 1; USF1: Upstream stimulatory factor 1; VEGFA: Vascular endothelial growth factor A; YBX1: Y-box binding protein 1; ZEB1: Zinc finger E-box binding homeobox 1.