Extracellular volatilomic alterations induced by hypoxia in breast cancer cells

• Main Author: Taware, Ravindra
• Publication Date: 2020
• Other Authors: Taunk, Khushman, Kumar, Totakura V. S., Pereira, Jorge A. M., Câmara, José S., Nagarajaram, H. A., Kundu, Gopal C., Rapole, Srikanth
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10400.13/3877
• topic: Breast cancer cells; Hypoxia; Extracellular volatilomic alterations; .; Faculdade de Ciências Exatas e da Engenharia; Centro de Química da Madeira

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 reconfguration 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 profled by standard GC–MS system. Univariate and multivariate statistical approaches (p<0.05, Log2 FC≥0.58/≤−0.58, PC1>0.13/<−0.13) were applied to select the VOMs diferentially 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 signifcantly altered (p<0.05, PC1>0.13/< −0.13) upon hypoxic exposure to BC cells. Further, cell line specifc 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 signifcantly 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 specifc to normoxia and 6 were found common to both the conditions. Formic acid was identifed 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 signifcantly altered in aggressive as compared to non-aggressive cells in normoxia and hypoxia respectively. Conclusions Higher formate overfow 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 efcient whereas, under normoxia, fatty acid biosynthesis was favoured when compared to non-aggressive cells.