Carla Luis1, Fernanda Duarte2, Isabel Faria3, Ivana Jarak4, Pedro F Oliveira5, Marco G Alves6, Raquel Soares7, Rúben Fernandes8. 1. School of Health, Polytechnic of Porto (ESS/P.PORTO), Porto, Portugal; Biochemistry Unit, Department of Biomedicine, Faculty of Medicine, University of Porto (FMUP), Porto, Portugal; Instituto de Inovação e Investigação em Saúde (I3S), University of Porto, Portugal. 2. School of Health, Polytechnic of Porto (ESS/P.PORTO), Porto, Portugal; CoreLab, Hospital Centre of Porto University (CHUP), Porto, Portugal. 3. School of Health, Polytechnic of Porto (ESS/P.PORTO), Porto, Portugal. 4. Department of Life Sciences, Faculty of Sciences and Technology, Centre for Functional Ecology (CFE), University of Coimbra, Coimbra; Laboratory of Cell Biology, Unit for Multidisciplinary Research in Biomedicine (UMIB), Department of Microscopy, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal. 5. Instituto de Inovação e Investigação em Saúde (I3S), University of Porto, Portugal; Laboratory of Cell Biology, Unit for Multidisciplinary Research in Biomedicine (UMIB), Department of Microscopy, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal; Department of Genetics, Faculty of Medicine, University of Porto, Portugal. 6. Laboratory of Cell Biology, Unit for Multidisciplinary Research in Biomedicine (UMIB), Department of Microscopy, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal. 7. Biochemistry Unit, Department of Biomedicine, Faculty of Medicine, University of Porto (FMUP), Porto, Portugal; Instituto de Inovação e Investigação em Saúde (I3S), University of Porto, Portugal. 8. School of Health, Polytechnic of Porto (ESS/P.PORTO), Porto, Portugal; Instituto de Inovação e Investigação em Saúde (I3S), University of Porto, Portugal; Faculty of Medicine, University of Santiago de Compostela, Galiza, Spain. Electronic address: ruben@ess.ipp.pt.
Abstract
AIMS: Obesity is a complex health disorder and a trigger to many diseases like Diabetes mellitus (DM) and breast cancer (BrCa), both leading causes of morbidity and mortality worldwide. Also evidence demonstrates that abnormal glucose metabolism termed 'the Warburg effect' in cancer cell is closely associated with malignant phenotypes and promote the aggressiveness of several types of cancer, including BrCa. In this study, we evaluated the breast cancer cell metabolism in normoglycemia, hyperglycemia and in an obesity condition in order to clarify the potential underlined mechanisms that link these disorders. MATERIALS AND METHODS: MCF-7 cells were exposed to low and high glucose levels, the latter either in the presence of 3T3-L1 adipocyte conditioned medium (CM), thus mimicking the adiposity observed in obese patients. Cell viability, migration, proliferation, cytotoxicity and cell death assays were performed under the different culture conditions. Hormonal and lipid profile were also characterized by biochemical assays and primary metabolism was determined by Nuclear Magnetic Resonance (NMR)-based metabolomics. RESULTS: Our results show an increased aggressiveness in the condition mimicking diabetogenic obesity with an altered energy/lipid metabolism. Interestingly in the experimental obesity-mimicking status, lipids and amino acids were expended while glucose was produced by tumor cells from lactate. These findings reveal a shift on tumor cells metabolism that is opposite to 'the Warburg effect'. CONCLUSIONS: Overall, this experimentally obesity-mimicking condition not only revealed an increased tumor proliferation and aggressiveness but also disclosed a new mechanism of cancer metabolism, the 'Warburg Effect Inversion'.
AIMS: Obesity is a complex health disorder and a trigger to many diseases like Diabetes mellitus (DM) and breast cancer (BrCa), both leading causes of morbidity and mortality worldwide. Also evidence demonstrates that abnormal glucose metabolism termed 'the Warburg effect' in cancer cell is closely associated with malignant phenotypes and promote the aggressiveness of several types of cancer, including BrCa. In this study, we evaluated the breast cancer cell metabolism in normoglycemia, hyperglycemia and in an obesity condition in order to clarify the potential underlined mechanisms that link these disorders. MATERIALS AND METHODS: MCF-7 cells were exposed to low and high glucose levels, the latter either in the presence of 3T3-L1 adipocyte conditioned medium (CM), thus mimicking the adiposity observed in obesepatients. Cell viability, migration, proliferation, cytotoxicity and cell death assays were performed under the different culture conditions. Hormonal and lipid profile were also characterized by biochemical assays and primary metabolism was determined by Nuclear Magnetic Resonance (NMR)-based metabolomics. RESULTS: Our results show an increased aggressiveness in the condition mimicking diabetogenic obesity with an altered energy/lipid metabolism. Interestingly in the experimental obesity-mimicking status, lipids and amino acids were expended while glucose was produced by tumor cells from lactate. These findings reveal a shift on tumor cells metabolism that is opposite to 'the Warburg effect'. CONCLUSIONS: Overall, this experimentally obesity-mimicking condition not only revealed an increased tumor proliferation and aggressiveness but also disclosed a new mechanism of cancer metabolism, the 'Warburg Effect Inversion'.