Vol.:(0123456789) 1 3 Metabolomics (2020) 16:21 https://doi.org/10.1007/s11306-020-1635-x ORIGINAL ARTICLE Extracellular volatilomic alterations induced by hypoxia in breast cancer cells Ravindra Taware 1  · Khushman Taunk 1  · Totakura V. S. Kumar 2  · Jorge A. M. Pereira 3  · José S. Câmara 3,4  · H. A. Nagarajaram 5  · Gopal C. Kundu 2,6  · Srikanth Rapole 1 Received: 5 September 2019 / Accepted: 3 January 2020 / Published online: 24 January 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract Introduction The metabolic shift induced by hypoxia in cancer cells has not been explored at volatilomic level so far. The volatile organic metabolites (VOMs) constitute an important part of the metabolome and their investigation could provide us crucial aspects of hypoxia driven metabolic reconfiguration in cancer cells. Objective To identify the altered volatilomic response induced by hypoxia in metastatic/aggressive breast cancer (BC) cells. Methods BC cells were cultured under normoxic and hypoxic conditions and VOMs were extracted using HS-SPME approach and profiled by standard GC–MS system. Univariate and multivariate statistical approaches (p < 0.05, Log 2 FC ≥ 0.58/≤ − 0.58, PC1 > 0.13/< − 0.13) were applied to select the VOMs differentially altered after hypoxic treatment. Metabolic pathway analysis was also carried out in order to identify altered metabolic pathways induced by the hypoxia in the selected BC cells. Results Overall, 20 VOMs were found to be significantly altered (p < 0.05, PC1 > 0.13/< − 0.13) upon hypoxic exposure to BC cells. Further, cell line specific volatilomic alterations were extracted by comparative metabolic analysis of aggressive (MDA-MB-231) vs. non-aggressive (MCF-7) cells incubated under hypoxia and normoxia. In this case, 15 and 12 VOMs each were found to be significantly altered in aggressive cells when exposed to hypoxic and normoxic condition respectively. Out of these, 9 VOMs were found to be uniquely associated with hypoxia, 6 were specific to normoxia and 6 were found common to both the conditions. Formic acid was identified as the most prominent molecule with higher abundance levels in aggressive as compared to non-aggressive cells in both conditions. Furthermore, metabolic pathway analyses revealed that fatty acid biosynthesis and nicotinate and nicotinamide metabolism were significantly altered in aggressive as compared to non-aggressive cells in normoxia and hypoxia respectively. Conclusions Higher formate overflow was observed in aggressive cells compared to non-aggressive cells incubated under both the conditions, reinforcing its correlation with aggressive and invasive cancer type. Moreover, under hypoxia, aggres- sive cells preferred to be bioenergetically more efficient whereas, under normoxia, fatty acid biosynthesis was favoured when compared to non-aggressive cells. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11306-020-1635-x) contains supplementary material, which is available to authorized users. * Srikanth Rapole rsrikanth@nccs.res.in 1 Proteomics Lab, National Centre for Cell Science, Ganeshkhind, Pune 411007, India 2 Laboratory of Tumor Biology, Angiogenesis and Nanomedicine Research, National Centre for Cell Science (NCCS), Ganeshkhind, Pune 411007, India 3 CQM – Centro de Química da Madeira, Universidade da Madeira, Campus Universitário da Penteada, 9020105 Funchal, Portugal 4 Faculdade de Ciências Exatas E da Engenharia, Universidade da Madeira, Campus Universitário da Penteada, 9020-105 Funchal, Portugal 5 Department of Systems and Computational Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India 6 Present Address: School of Biotechnology, KIIT Deemed to be University, Institute of Eminence, Bhubaneswar 751024, India