LncRNA-Mediated miR-145 Sponging Drives FN1 and CCND1 Expression: Prognostic and Therapeutic Targets in NSCLC

<b>Background:</b> Non-small cell lung cancer (NSCLC) progression is driven by dysregulated competing endogenous RNA (ceRNA) networks, where non-coding RNAs sequester miRNAs to modulate oncogene expression. The tumor-suppressor miR-145 is frequently downregulated in NSCLC, but its lncRNA-mediated regulation remains incompletely characterized. <b>Methods:</b> Integrated transcriptomic analysis of NSCLC datasets (GSE135304: blood RNA from 712 patients; GSE203510: plasma miRNAs) was used to identify dysregulated genes (|log2FC| > 0.1, <i>p</i> < 0.05) and miRNAs (|log2FC| > 1, <i>p</i> < 0.05). Experimentally validated targets from miRTarBase/TarBase were intersected with dysregulated genes, followed by WikiPathways/GO enrichment. ceRNA networks were constructed via co-expression analysis. RT-qPCR validated miR-145-3p expression in A549/MRC-5 cells and NSCLC tissues. GEPIA assessed FN1/CCND1 clinical relevance. <b>Results:</b> We identified 8271 dysregulated genes and 52 miRNAs. miR-145-3p, critical in immune regulation, was significantly downregulated (log2FC = -1.24, <i>p</i> = 0.036). Intersection analysis revealed 27 miR-145-3p targets (e.g., FN1, CCND1, SMAD3) enriched in immune pathways (FDR < 0.05) and TGF-β-mediated EMT within the dysregulated geneset. Six immune-linked hub genes emerged. LncRNAs LOC729919 and LOC100134412 showed strong co-expression with hub genes and competitively bind miR-145-3p, derepressing the expression of the metastasis drivers FN1 (ECM regulator) and CCND1 (cell cycle controller). This ceRNA axis operates within a broader dysregulation of ATM-dependent DNA damage, Hippo signaling, and cell cycle pathways. RT-qPCR confirmed significant miR-145-3p suppression in NSCLC models (<i>p</i> < 0.05). GEPIA revealed a significant FN1-CCND1 co-expression (<i>p</i> = 0.0017). <b>Conclusions:</b> We characterize a novel LOC729919/LOC100134412-miR-145-FN1/CCND1 ceRNA axis in NSCLC pathogenesis. FN1's prognostic value and functional linkage to CCND1 underscores its potential clinical relevance for therapeutic disruption.