MiR-124-3p Suppresses Glioma Cells Progression by Targeting STAT3/NAMPT and Inhibiting AKT/ERK Signaling

Background: In our preliminary study, bioinformatics analyses identified differentially expressed miRNAs and mRNAs in glioma versus peritumoral samples, with functional validation of multiple miRNA-mRNA regulatory axes. MicroRNA-124-3p (miR-124-3p)/nicotinamide phosphoribosyltransferase (NAMPT) was among these axes and may critically regulate glioma malignant phenotypes, and this study aimed to validate their regulatory interactions. Methods: We analyzed NAMPT expression in glioma tissues using clinical datasets from the Chinese Glioma Genome Atlas (CGGA). Functional effects of miR-124-3p and NAMPT were evaluated in U87 and U251 glioma cells using quantitative real-time PCR (qRT-PCR), Western blotting, colony formation assays, CCK-8 cell viability assays, Transwell invasion assays, and flow cytometry. The direct interaction between miR-124-3p and NAMPT was investigated using dual-luciferase reporter assays. Results: Clinical data revealed that elevated NAMPT expression correlated with poor prognosis, advanced pathological grade, and IDH-wild-type gliomas. MiR-124-3p overexpression significantly inhibited glioma cell proliferation, migration, and invasion while promoting apoptosis. Mechanistically, miR-124-3p downregulated NAMPT expression through regulation, leading to suppression of the p-AKT and p-ERK signaling pathways. Notably, NAMPT overexpression rescued the tumor-suppressive effects of miR-124-3p, confirming its critical role in this axis. However, dual-luciferase reporter assays ruled out a direct interaction between miR-124-3p and the NAMPT transcript, suggesting an indirect regulatory mechanism. Further investigation through WB and rescue experiments identified the transcription factor STAT3 as the key intermediary, serving as a functional bridge linking miR-124-3p to the regulation of NAMPT expression. Discussion: Accumulating evidence demonstrates that miR-124-3p functions as a potent tumor suppressor across diverse malignancies through distinct molecular mechanisms. STAT3, which is directly targeted by miR-124-3p, serves as the functional bridge linking miR-124-3p to NAMPT regulation. NAMPT, as a critical node in the NAD⁺ biosynthetic pathway, influences the malignant biological behavior of glioma through downstream PI3K/AKT and MEK/ERK signaling transduction pathways. Conclusion: MiR-124-3p functions as a tumor suppressor in glioma by repressing STAT3/NAMPT-mediated AKT/ERK signaling, highlighting its potential as a diagnostic biomarker and therapeutic target for glioma management.