(1) Oxaliplatin-based chemotherapy for colorectal cancer liver metastasis is associated with sinusoidal injury of liver parenchyma. The effects of oxaliplatin-induced liver injury on the protein level remain unknown. (2) Protein expression in liver tissue was analyzed-from eight patients treated with FOLFOX (combination of fluorouracil, leucovorin, and oxaliplatin) and seven controls-by label-free liquid chromatography mass spectrometry. Recursive feature elimination-support vector machine and Welch t-test were used to identify classifying and relevantly changed proteins, respectively. Resulting proteins were analyzed for associations with gene ontology categories and pathways. (3) A total of 5891 proteins were detected. A set of 184 (3.1%) proteins classified the groups with a 20% error rate, but relevant change was observed only in 55 (0.9%) proteins. The classifying proteins were associated with changes in DNA replication (p < 0.05) through upregulation of the minichromosome maintenance complex and with the innate immune response (p < 0.05). The importance of DNA replication changes was supported by the results of Welch t-test (p < 0.05). (4) Six weeks after FOLFOX treatment, less than 1% of identified proteins showed changes in expression associated with DNA replication, cell cycle entry, and innate immune response. We hypothesize that the changes remain after recovery from FOLFOX treatment injury.
Keywords: DNA replication; innate immune response; label-free liquid chromatography mass spectrometry; minichromosome maintenance complex; oxaliplatin-based chemotherapy; protein expression; recovery of liver injury.