Proteomic analysis reveals a 4-methylumbelliferone-induced metabolic shift accompanied by reduced CD147 expression and MMP-2 activity in U937 cells

<title>Abstract</title> <p>Acute Myeloid Leukemia (AML) is a hematological malignancy with poor therapeutic outcomes, as up to 50% of patients relapse or become refractory to treatment. The identification of novel therapeutic strategies therefore remains an unmet clinical need. 4-Methylumbelliferone (4MU), a clinically approved inhibitor of hyaluronan synthesis, has demonstrated antitumor properties in several cancers and represents a promising candidate for drug repositioning. To explore its mechanisms of action in AML, we employed the U937 cell line, in which 4MU inhibits proliferation without affecting hyaluronic acid synthesis, enabling the study of HA-independent pathways. Proteomic profiling revealed that 4MU modulated proteins primarily associated with cellular metabolism. Consistently, SCENITH assays demonstrated reduced glycolytic activity accompanied by increased mitochondrial dependence, suggesting a metabolic shift toward OXPHOS, along with enhanced utilization of glutaminolysis and fatty acid oxidation pathways. Among the differentially expressed proteins, CD147 was selected for further validation because of its established role in metabolic reprogramming and tumor progression. Here, we demonstrate for the first time that 4MU downregulates CD147 expression in U937 cells, as confirmed by flow cytometry and immunofluorescence, and reduces MMP-2 activity. Together, our findings uncover a novel HA-independent mechanism of 4MU action characterized by metabolic reprogramming, CD147 downregulation, and reduced MMP-2 activity, supporting its repositioning as a therapeutic agent for AML.</p>