Urokinase receptor gene PLAUR as a regulator of epithelial-mesenchymal transition gene expression and migration of glioma and neuroblastoma cells

Introduction. The proteins of the urokinase system, including serine protease urokinase (uPA), its receptor (uPAR), and inhibitors PAI-1 and PAI-2, play a key role in tumor biology by influencing cellular proliferation and tumor growth, invasion, metastasis, and angiogenesis. Despite the established role of these proteins in the carcinogenesis of many tumor types, the mechanisms underlying their action, including their effects on cell migration, epithelial-mesenchymal transition, and stemness, remain insufficiently studied.
Aim. To evaluate the influence of the urokinase receptor gene PLAUR on the expression of adhesion and stemness genes, as well as on the migration of human glioma and neuroblastoma cells.
Materials and methods. The study utilized two human glioma cell lines, U87 and U251, and the human neuroblastoma cell line SH-SY5Y. To achieve the overexpression of the PLAUR gene, a non-viral plasmid was created, followed by the transfection of the cells. Relative gene expression was assessed using real-time polymerase chain reaction. For evaluating cell migration, a Wound Healing Assay was performed, with image analysis conducted using ImageJ software and MRI Wound Healing Tool. Statistical analysis of the results was carried out using GraphPad Prism v.10.
Results. High expression of the urokinase receptor gene PLAUR is associated with a significant increase in cell migration and complex phenotypic changes. Specifically, in U251 glioma cells, there is an induction of the expression of the genes CD56, CDH1, CDH2, ZEB2, and SOX2. In U87 glioma cells, the expression of the genes PLAU, CD56, CDH1, ZEB1, ZEB2, SNAI1, SNAI2, SOX2, and NANOG is induced, while the expression of the gene CDH2 is suppressed. In SH-SY5Y neuroblastoma cells, there is an induction of the expression of the genes CD56, CDH1, ZEB1, ZEB2, SNAI2, and SOX2, along with a suppression of the expression of the urokinase gene PLAU compared to cells transfected with the control plasmid pGFP.
Conclusion. The results highlight the complexity of the regulation of carcinogenesis processes involving the PLAUR gene and deepen our understanding of tumour biology. High expression of the PLAUR gene may enhance the activity and invasion of tumor cells by regulating the epithelial-mesenchymal transition and altering the expression of key transcription factors.

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