Metabolomics study of the effects of eucalyptus bark compounds on human breast tumor and non-tumor epithelial cells ; Estudo metabolómico dos efeitos de compostos da casca de eucalipto em células humanas de mama tumorais e não tumorais

Agro-industrial exploitation of eucalyptus for pulp production generates large amounts of biomass residues, particularly bark. Eucalyptus spp. barks are a rich source of several triterpenoids, mostly triterpenic acids (TAs). TAs have been demonstrated to modulate numerous signaling pathways involved in carcinogenesis, which may be closely linked to cellular metabolic reprogramming. Given the limited information on the metabolic modulatory activity of eucalyptus bark compounds, the work performed in this thesis aimed at comprehensively assessing the metabolic effects of a lipophilic E. nitens outer bark extract and two TAs (betulinic and ursolic acids) in triple negative breast cancer (TNBC) and non-tumor breast cells. Integrative NMR metabolomics of cell culture media, intracellular polar metabolites and cellular lipids was used for that purpose. Chapter 1 introduces some general aspects on breast cancer, such as subtype classification and therapeutic options, and informs on current uses of plant-derived natural products in anticancer therapy, focusing on TAs. Then, the main metabolic dysregulations known to be associated with breast cancer are reviewed, as well as current knowledge on metabolic modulation by TAs and other isoprenoids. Finally, the metabolomics approach is presented, together with a brief state of the art on its applications in the study of breast cancer cells and their metabolic responses to plant-derived natural products. In Chapter 2, the basal metabolic activity and composition of the two cell types used in this work (MDA-MB-231 TNBC cells and MCF-10A non-tumor epithelial cells) are thoroughly described. Based on consumption and excretion patterns, together with analysis of polar endometabolome and lipid composition, metabolic pathway differences were inferred and correlated with the high demand of TNBC cells for macromolecular biosynthesis, energy production and redox control. Chapter 3 addresses the effects of a lipophilic E. nitens outer bark extract on the metabolism of MDA-MB-231 and ...