Fig. 1: Redox proteomics of lung tumor and tumor-adjacent healthy tissue reveals intra- and extracellular differences.

A Volcano plot depicting proteins whose redox state was significantly affected in tumor versus healthy tissue. Each dot represents an individual cysteine residue, i.e., median value of L/H ratios of all peptides harboring a given cysteine (labeled black: significantly changed proteins (FDR corrected p value < 0.05, S0 = 0.1); specific pathways of interest, e.g., glucose and methylglyoxal metabolism, are highlighted in green and pink, respectively). B Venn diagram depicting a number of overlapping and significantly more oxidized proteins in tumor vs. healthy tissue. According to the UniProt annotation of individual proteins for their subcellular location, tumor tissue showed higher oxidation of intracellular proteins and lower oxidation of extracellular proteins than healthy tissue. C (top) Protein abundances (LFQ values) of superoxide dismutase (SOD) 1 and 2 (cytosolic and mitochondrial isoform; N = 64 (SOD1) and 69 (SOD2) paired tumor and healthy tissue pieces, two-sided paired t tests) were higher while protein abundance of SOD3 (extracellular, secreted isoform; N = 66 two-sided paired t tests) was lower in tumor tissue; (bottom) Two extracellular oxidative proteins, namely myeloperoxidase (MPO) and eosinophil peroxidase (EPX) were also lower in tumor tissue (N = 69 (MPO) or 68 (EPX) paired tumor and healthy tissue pieces; two-sided paired t tests). D The top 25 non-redundant significantly enriched terms upon GOBP enrichment analysis with all significantly (Student’s t test p value < 0.05) redox-affected proteins as input (FDR for enrichments was always <0.05). Genes (%) represents the number of matched genes to the total size of the term. Exact FDR values for enrichment are noted on the side of the bar chart. Supplementary Data 3 and 4 are source data for A, B and D, while for C source data is provided in Source Data File.