Project description:Hypoxia is known to regulate tumor-initiating cells and to have an effect on miRNA expression. We were interested in studying the role of hypoxia-induced miR-210 in colorectal cancer patient-derived sphere cultures. Downregulated genes after overexpression of miR-210 were retained as potential miR-210 target genes for further validation sudies.
Project description:The effect of the overexpression of Plant Cysteine Oxidase (PDCO1) on the transcriptome of Arabidopsis resettes was investigated with plants subjected to a 4h hypoxia (5% O2 v/v in air). For this purpose, 4-week old rosette of wild-type and 35S:FLAG:CDO1 plants were compared. Samples were composed of pools of 5 plants. In total, 6 samples were analyzes, subdivided in 2 thesis with 3 replicates each. 35S:PCO1 plants (treated with hypoxia) were compared to wild-type plants (treated with hypoxia).
Project description:Rapidly proliferating tumors are exposed to a hypoxic microenvironment due to their density, high metabolic consumption, and interruptions in blood flow due to immature angiogenesis. Cellular responses to hypoxia promote highly malignant and metastatic behavior, as well as a chemotherapy-resistant state. In order to better understand the complex relationships between hypoxic adaptations and cancer progression, we studied the dynamic proteome responses of glioblastoma cells exposed to hypoxia via an innovative approach: quantification of newly synthesized proteins using heavy stable-isotope arginine labeling combined with accurate assessment of cell replication by quantification of the light/heavy arginine ratio of peptides in histone H4. We found that hypoxia affects cancer cells in multiple intertwined ways: inflammation, typically with over-expressed glucose transporter (GLUT1), DUSP4/ MKP2, and RelA proteins; a metabolic adaptation with overexpression of all glycolytic pathway enzymes for pyruvate/lactate synthesis; and the EMT (epithelial-mesenchymal transition) and cancer stem cell (CSC) renewal with characteristic morphological changes and mesenchymal/CSC protein expression profiles. For the first time, we identified the vitamin B12 transporter protein TCN2, which is essential for one-carbon metabolism, as being significantly downregulated. Further, we found, by knockdown and overexpression experiments, that TCN2 plays an important role in controlling cancer cell transformation towards the highly aggressive mesenchymal/CSC stage; low expression of TCN2 has an effect similar to hypoxia, while high expression of TCN2 can reverse it. We conclude that hypoxia induces sequential metabolic responses of one-carbon metabolism in tumor cells.
Project description:Hypoxia stress (<1% oxygen) followed by reoxygenation, is accompanied by formation of reactive oxygen species (ROS) and nitric oxide (NO), which act as signaling molecules, but also cause nitro-oxidative stress. The NO concentration is regulated by phytoglobins (formerly hemoglobins) in the NO cycle. To understand how changes in phytoglobin expression affect plant metabolism under hypoxia, we studied the proteome and metabolome of barley (Hordeum vulgare L., cv. Golden Promise) plants without (WT) or with (HO) overexpression of phytoglobins. WT plants were more susceptible to hypoxia than HO. The chlorophyll a+b content was lowered by 50% and biomass by 30% in WT24, compared to WT, while HO plants were unaffected. We observe increase in ROS production during hypoxia treatment in WT seedlings had that was not observed in HO seedlings. But most importantly we identified and quantified 9694 proteins out of which 1107 changed significantly in abundance in at least one of the four comparisons – HO/WT andHO24/WT24) (giving genotype differences), WT24/WT and HO24/HO giving treatment differences. The main proteome changes between genotypes shown that many proteins were downregulated in HO24/HO but not in WT24/WT, such as ion transporters, Ca2+ signal transduction, and proteins related to protein degradation. We also identified and quantified 1470 metabolites, and the abundance of >500 changed significantly. Hypoxia had a much larger overall effect on the metabolome than overexpression of phytoglobin. The metabolites that have the biggest influence on the differences between treatments were selected for further analysis, among them many amino acids, putrescine and metabolites taking part in glycolysis.