Virtual screening-guided repurposing of fluorescent probes to detect EGFR expression in renal cells.

Epidermal Growth Factor Receptor (EGFR) signalling plays a key role in the progression of chronic kidney disease (CKD), as its persistent activation promotes inflammation, fibrosis, and tubular cell proliferation. Aberrant EGFR expression and overactivation have therefore been associated with renal injury and disease progression, making it a relevant biomarker and potential therapeutic target in CKD. Our goal was to repurpose known fluorescent ligands, originally developed for other targets, to study EGFR expression at the kidney cell membrane in healthy and diseased conditions, providing a potential tool for disease detection and staging. Drug repurposing leverages existing pharmacokinetic and safety data, reducing time and costs, and can transform off-target effects into new applications through structure-based and AI-driven approaches. We built a database of 47 commercially available fluorescent ligands with fully disclosed structures and screened them by molecular docking against EGFR. Two promising candidates were identified and validated through preliminary kinase inhibition assays. Their performance was then evaluated in three cell lines with different EGFR expression levels (RCC, HK-2, and EGFR-negative EA.hy926). Notably, the harmonic integration of in silico and experimental approaches proved effective in the rational repurposing of two fluorescent organic ligands as probes for the detection of EGFR overexpression in CKD.