Discovery and Validation of Metabolite Biomarkers in Breast Cancer Exosomes Using Liquid Chromatography-Mass Spectrometry

Abstract

Breast cancer (BC) is the second most diagnosed cancer in Canadian women. Early detection of this cancer is critical to improve patient survival and prognoses. Exosomes are proposed to be involved in tumor proliferation through the transfer of diverse biomolecules, including metabolites. The use of exosomes as biomarkers for early diagnosis of BC has recently garnered interest due to them having unique biomolecules in diseased cohorts. Hence, an untargeted metabolomic analysis of BC exosomes was performed using nano high-performance liquid chromatography coupled to tandem mass spectrometry (nLC-MS/MS) for BC diagnostic biomarker discovery. A total of 9 independent metabolite samples from non-tumorogenic MCF10A and highly metastatic MDA-MB-231 cell lines were analyzed. Bioinformatic analysis revealed 27 potential metabolite candidates unique to MDA-MB-231. Amongst 4 metabolites tested, one, N-Acetyl-L-Phenylalanine, was successfully validated. Overall, this study reveals that exosomes possess metabolites that can be candidates for early BC diagnosis.