TMT-based quantitative proteomic analysis Protein lysates were extracted from SLC25A18‑overexpressing HUCCT1 cells and corresponding control cells. Equal amounts of protein were reduced, alkylated, and digested with trypsin. The resulting peptides were labelled with TMT 6‑plex reagents, combined, and fractionated by high‑pH reversed‑phase HPLC. Each fraction was analysed by LC‑MS/MS on a Q Exactive HF‑X mass spectrometer. Raw spectra were searched against the UniProt human database using Proteome Discoverer, with peptide and protein identifications filtered at 1% FDR.