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Ferritin and HNE in human brain tumor tissue samples
Keywords: protein carbonyl derivates, plasma, idiopathic lung fibrosis, interstitial pneumonia
Keywords: ferritin, 4-HNE, brain tumors doi:10.1016/j.freeradbiomed.2012.08.051
doi:10.1016/j.freeradbiomed.2012.08.050 HNE.P.22 HNE.P.21 Ferritin and HNE in human brain tumor tissue samples H. Jaksch-Bogensperger 1, T. Landrichinger1, S. Weis3, P. Eckl2, C. Hauser-Kronberger1, N. Bresgen*2 et al 1 Paracelsus Medical University, Austria, 2University of Salzburg, Austria, 3Wagner-Jauregg Hospital, Austria Endocytosis of extracellular ferritin increases the level of free iron in lysosomes and promotes oxidative stress by the generation of OH-radicals via the Fenton reaction. As a consequence, there is lipid peroxidation (LPO), which causes lysosomal membrane permeabilisation (LMP) and the release of lysosomal enzymes together with LPO products further promoting cellular damage and cell death. In this context it is important to note that cells exposed to ferritin show both a particularly strong perinuclear accumulation of 4-HNE-modified proteins and a similar clustering of lysosomes. 4-HNE, besides its known cyto- and genotoxic potential, also mediates phosphorylation, binding and activation of the receptor tyrosine kinase EGFR by activating downstream signaling components involved in cell proliferation. Furthermore, 4-HNE acts as a physiological factor, essential for growth and differentiation as well as transformation and apoptosis. Especially the low levels of 4-HNE generated during oxidative stress induce proliferation and induce VEGF expression and secretion, which may induce angiogenic signals in endothelial cells, as was preliminary shown. Therefore the relationship between ferritin and 4-HNE and their potential regulatory role during tumor neovascularisation may explain the aggressiveness of high grade brain tumors. Since conditioned media collected from different human brain tumor cell lines secrete apoptosis-inducing isoferritins and growth promoting factors - as evidenced by the analysis of their proliferation stimulating activity on primary hepatocytes, we investigated the localization of 4-HNE and ferritin in paraffin-embedded brain tumor tissue samples (glioma,astrocytoma, meningioma). In fact, 4-HNE-modified proteins were detectable in a fraction (27%) of the available samples - mostly glioblastoma multiforme - in vesicular structures close to the nucleus, whereas ferritin was mainly detected in the cytoplasm. These results eventually indicate a correlation of 4-HNE-positive samples with increased tumor malignity.
S254
Apc mutation increases metabolization capacities of mouse colonocytes towards the dietary lipid oxidation product 4-hydroxynonenal F. Guéraud*, M. Baradat, I. Jouanin, L. Debrauwer, S. Dalleau, F. Pierre et al INRA, France Red and processed meat consumption is associated to an increased colorectal cancer risk. Heme iron concentration is high in red and processed meat. It is a pro-oxidant compound able to induce in food, or during digestion, the formation of secondary lipid oxidation products such as 4-hydroxynonenal (HNE), a cytotoxic and genotoxic compound. In a previous study we had shown that immortalized mouse colonocytes were more resistant to the cytotoxic effect of HNE when they were mutated on the Apc (Adenomatous polyposis coli) gene. Apc mutation is an early and frequent mutation during the development of human colorectal cancer. In the present study, we investigated the metabolization capacities towards HNE of these immortalized mouse colonocytes, bearing or not the mutation of the Apc gene. Apc mutated cells metabolized HNE much more rapidly and completely than normal cells. The different metabolites were identified by the mean of mass spectrometry and NMR analyses. The amount of cysteine and glutathione conjugates and oxidized metabolites was greater in preneoplastic cells, compared to normal ones. We analysed the expression of the enzymes possibly involved in these metabolization pathways by quantitative-PCR and found them differentially expressed between the two cell lines. These enzymes appear to be under the regulation of the Nrf2/antioxidant responsive element (ARE) pathway, involved in the cellular antioxidant defences. HNE could be one of the missing links between red meat and colorectal cancer, by selection, in a "peroxidizing environment", of preneoplastic cells that present higher antioxidant defences. Keywords: lipid peroxidation, colorectal cancer, 4hydroxynonenal, biotransformation doi:10.1016/j.freeradbiomed.2012.08.052
Keywords: ferritin, 4-HNE, brain tumors doi:10.1016/j.freeradbiomed.2012.08.051
doi:10.1016/j.freeradbiomed.2012.08.050 HNE.P.22 HNE.P.21 Ferritin and HNE in human brain tumor tissue samples H. Jaksch-Bogensperger 1, T. Landrichinger1, S. Weis3, P. Eckl2, C. Hauser-Kronberger1, N. Bresgen*2 et al 1 Paracelsus Medical University, Austria, 2University of Salzburg, Austria, 3Wagner-Jauregg Hospital, Austria Endocytosis of extracellular ferritin increases the level of free iron in lysosomes and promotes oxidative stress by the generation of OH-radicals via the Fenton reaction. As a consequence, there is lipid peroxidation (LPO), which causes lysosomal membrane permeabilisation (LMP) and the release of lysosomal enzymes together with LPO products further promoting cellular damage and cell death. In this context it is important to note that cells exposed to ferritin show both a particularly strong perinuclear accumulation of 4-HNE-modified proteins and a similar clustering of lysosomes. 4-HNE, besides its known cyto- and genotoxic potential, also mediates phosphorylation, binding and activation of the receptor tyrosine kinase EGFR by activating downstream signaling components involved in cell proliferation. Furthermore, 4-HNE acts as a physiological factor, essential for growth and differentiation as well as transformation and apoptosis. Especially the low levels of 4-HNE generated during oxidative stress induce proliferation and induce VEGF expression and secretion, which may induce angiogenic signals in endothelial cells, as was preliminary shown. Therefore the relationship between ferritin and 4-HNE and their potential regulatory role during tumor neovascularisation may explain the aggressiveness of high grade brain tumors. Since conditioned media collected from different human brain tumor cell lines secrete apoptosis-inducing isoferritins and growth promoting factors - as evidenced by the analysis of their proliferation stimulating activity on primary hepatocytes, we investigated the localization of 4-HNE and ferritin in paraffin-embedded brain tumor tissue samples (glioma,astrocytoma, meningioma). In fact, 4-HNE-modified proteins were detectable in a fraction (27%) of the available samples - mostly glioblastoma multiforme - in vesicular structures close to the nucleus, whereas ferritin was mainly detected in the cytoplasm. These results eventually indicate a correlation of 4-HNE-positive samples with increased tumor malignity.
S254
Apc mutation increases metabolization capacities of mouse colonocytes towards the dietary lipid oxidation product 4-hydroxynonenal F. Guéraud*, M. Baradat, I. Jouanin, L. Debrauwer, S. Dalleau, F. Pierre et al INRA, France Red and processed meat consumption is associated to an increased colorectal cancer risk. Heme iron concentration is high in red and processed meat. It is a pro-oxidant compound able to induce in food, or during digestion, the formation of secondary lipid oxidation products such as 4-hydroxynonenal (HNE), a cytotoxic and genotoxic compound. In a previous study we had shown that immortalized mouse colonocytes were more resistant to the cytotoxic effect of HNE when they were mutated on the Apc (Adenomatous polyposis coli) gene. Apc mutation is an early and frequent mutation during the development of human colorectal cancer. In the present study, we investigated the metabolization capacities towards HNE of these immortalized mouse colonocytes, bearing or not the mutation of the Apc gene. Apc mutated cells metabolized HNE much more rapidly and completely than normal cells. The different metabolites were identified by the mean of mass spectrometry and NMR analyses. The amount of cysteine and glutathione conjugates and oxidized metabolites was greater in preneoplastic cells, compared to normal ones. We analysed the expression of the enzymes possibly involved in these metabolization pathways by quantitative-PCR and found them differentially expressed between the two cell lines. These enzymes appear to be under the regulation of the Nrf2/antioxidant responsive element (ARE) pathway, involved in the cellular antioxidant defences. HNE could be one of the missing links between red meat and colorectal cancer, by selection, in a "peroxidizing environment", of preneoplastic cells that present higher antioxidant defences. Keywords: lipid peroxidation, colorectal cancer, 4hydroxynonenal, biotransformation doi:10.1016/j.freeradbiomed.2012.08.052