MicroRNA-125b-5p Drives MMP-2 Expression via Activation of RAGE-38MAPK-p65/p50NF-κB Axis: A Novel Mechanism in Human Lung Cancer Cells.

Dysregulated microRNA-mediated control of matrix metalloproteinase-2 (MMP-2) plays a pivotal role in lung cancer (LC) progression, though the inflammatory signaling mechanisms governing its regulation remain poorly understood. This study reveals how S100A4-activated RAGE signaling modulates MMP-2 expression through microRNA-125b-5p (miR-125b-5p) in human LC cells. Potential miRNA target genes were computationally predicted using TargetScan algorithms. Functional interaction between miR-125b-5p and MMP-2 3'UTR was experimentally validated through dual-luciferase reporter assays incorporating full-length MMP-2 3'UTR sequence. Further validation was performed through transfection with miRNA inhibitors or mimics. To delineate the underlying mechanisms, key pathways were inhibited using small-molecule antagonists targeting p38-MAPK and NF-κB. Our analysis identified a conserved miR-125b-5p binding site in the MMP-2 3'UTR. In A549 cells, S100A4 induced reciprocal regulation, simultaneously upregulating MMP-2 and downregulating miR-125b-5p, with luciferase assays confirming direct targeting. Pre-miR-125b-5p transfection effectively reduced endogenous MMP-2 levels, while p38-MAPK/NF-κB activation mediated this regulation by suppressing miR-125b-5p consequently elevating MMP-2 expression. These findings were further validated in another human LC cell, SHP-77. These findings provide the first evidence demonstrating that miR-125b-5p directly regulates MMP-2 in LC, establishing S100A4-RAGE⟶p38/NF-κB⟶miR-125b-5p⟶MMP-2 axis as a novel regulatory pathway. The results position miR-125b-5p as a dual-action biomarker and therapeutic target against MMP-2-driven LC metastasis, offering new insights into critical inflammation-to-cancer connections.