Bioactive food components, cancer cell growth limitation and reversal of glycolytic metabolism
Keijer, J. ; Bekkenkamp-Grovestein, M. ; Venema, D.P. ; Dommels, Y.E.M. - \ 2011
Biochimica et Biophysica Acta. B, Bioenergetics 1807 (2011)6. - ISSN 0005-2728 - p. 697 - 706.
one-carbon metabolism - alpha-lipoic-acid - mitochondrial oxygen-consumption - polyunsaturated fatty-acids - activated protein-kinase - hypoxia-inducible factor - aberrant crypt foci - beta-carotene - lung-cancer - ppar-gamma
Cancer cells are resistant to apoptosis and show a shift in energy production from mitochondrial oxidative phosphorylation to cytosolic glycolysis. Apoptosis resistance and metabolic reprogramming are linked in many cancer cells and both processes center on mitochondria. Clearly, mutated cancer cells escape surveillance and turn into selfish cells. However, many of the mechanisms that operate cellular metabolic control still function in cancer cells. This review describes the metabolic importance of glucose and glutamine, glycolytic enzymes, oxygen, growth cofactors and mitochondria and focuses on the potential role of bioactive food components, including micronutrients. The role of B- and A-vitamin cofactors in (mitochondrial) metabolism is highlighted and the cancer protective potential of omega-3 fatty acids and several polyphenols is discussed in relation to metabolic reprogramming, including the mechanisms that may be involved. Furthermore, it is shown that cancer cell growth reduction by limiting the growth cofactor folic acid seems to be associated with reversal of metabolic reprogramming. Altogether, reversal of metabolic reprogramming may be an attractive strategy to increase susceptibility to apoptotic surveillance. Food bioactive components that affect various aspects of metabolism may be important tools to reverse glycolytic to oxidative metabolism and enhance sensitivity to apoptosis. The success of such a strategy may depend on several actors, acting in concert. Growth cofactors may be one of these, which call for careful (re)evaluation of their function in normal and in cancer metabolism
Adipose tissue failure and mitochondria as a possible target for improvement by bioactive food components
Keijer, J. ; Schothorst, E.M. van - \ 2008
Current Opinion in Lipidology 19 (2008)1. - ISSN 0957-9672 - p. 4 - 10.
polyunsaturated fatty-acids - conjugated linoleic-acid - diet-induced obesity - mechanisms linking obesity - activated receptor-gamma - hypoxia-inducible factor - union-of-pharmacology - metabolic syndrome - ppar-gamma - insulin-resistance
Purpose of review: Adipose tissue is an essential, highly dynamic and metabolically active tissue that vigorously communicates to support its primary function: the storage of lipids. It performs this function to secure energy supply and prevent lipotoxicity. Adipose tissue is essential for maintaining a healthy glucose and lipid homeostasis and failure results in disease. This review discusses causes of adipose tissue failure and four categories of bioactive food components that may help to prevent this. Recent findings: Based on recent findings, it is argued that initial adipose failure following long-term excess energy intake may be the result of reduced mitochondrial capacity associated with altered mitochondrial reactive oxygen species signaling and adipose tissue hypoxia. Current data suggest that different classes of bioactive food components, including vitamin B3, retinoids, fatty acids and polyphenols, may have the potential to modulate mitochondrial function and consequently prevent adipose dysfunction in obesity. Summary: It seems most attractive to aim nutritional intervention at the prevention of initial adipose dysfunction and hence to target dietary intervention at improvement of mitochondrial function.
Structure of the Redox Sensor Domain of Azotobacter vinelandii NifL at Atomic Resolution: Signaling, Dimerization, and Mechanism.
Key, J. ; Hefti, M.H. ; Purcell, E.B. ; Moffat, K. - \ 2007
Biochemistry 46 (2007)12. - ISSN 0006-2960 - p. 3614 - 3623.
plant photoreceptor domain - hypoxia-inducible factor - nitrogen-fixation genes - binding protein nifa - pas domain - oxygen sensor - crystal-structure - escherichia-coli - in-vitro - adiantum phytochrome3
NifL is a multidomain sensor protein responsible for the transcriptional regulation of genes involved in response to changes in cellular redox state and ADP concentration. Cellular redox is monitored by the N-terminal PAS domain of NifL which contains an FAD cofactor. Flavin-based PAS domains of this type have also been referred to as LOV domains. To explore the mechanism of signal recognition and transduction in NifL, we determined the crystal structure of the FAD-bound PAS domain of NifL from Azotobacter vinelandii to 1.04 Å resolution. The structure reveals a novel cavity within the PAS domain which contains two water molecules directly coordinated to the FAD. This cavity is connected to solvent by multiple access channels which may facilitate the oxidation of the FAD by molecular oxygen and the release of hydrogen peroxide. The structure contains a dimer of the NifL PAS domain that is structurally very similar to those described in other crystal structures of PAS domains and identifies a conserved dimerization motif. An N-terminal amphipathic helix constitutes part of the dimerization interface, and similar N-terminal helices are identified in other PAS domain proteins. The structure suggests a model for redox-mediated signaling in which a conformational change is initiated by redox-dependent changes in protonation at the N5 atom of FAD that lead to reorganization of hydrogen bonds within the flavin binding pocket. A structural signal is subsequently transmitted to the -sheet interface between the monomers of the PAS domain