Project description:The molecular role of iron in gene expression remains poorly characterized. Moreover, the alterations in global gene expression after iron chelation remains unclear and are important to assess for understanding the molecular pathology of iron-depletion and the biological effects of iron chelators. We assessed the effect on whole genome gene expression of two iron chelators (desferrioxamine and Dp44mT). These studies are important for understanding the molecular and cellular effects of iron-depletion.
Project description:Iron-deficiency affects 500 million people, yet the molecular role of iron in gene expression remains poorly characterized. Moreover, the alterations in global gene expression after iron chelation remains unclear and are important to assess for understanding the molecular pathology of iron-deficiency and the biological effects of iron chelators. We assessed the effect on whole genome gene expression of two iron chelators (desferrioxamine and 2-hydroxy-1-napthylaldehyde isonicotinoyl hydrazone) that have markedly different permeability properties. Sixteen genes were significantly regulated by both chelators, while a further 50 genes were regulated by either ligand. Most of the genes identified in this study have not been previously described to be iron-regulated and are important for understanding the molecular and cellular effects of iron-deficiency.
Project description:Iron-deficiency affects 500 million people, yet the molecular role of iron in gene expression remains poorly characterized. Moreover, the alterations in global gene expression after iron chelation remains unclear and are important to assess for understanding the molecular pathology of iron-deficiency and the biological effects of iron chelators. We assessed the effect on whole genome gene expression of two iron chelators (desferrioxamine and 2-hydroxy-1-napthylaldehyde isonicotinoyl hydrazone) that have markedly different permeability properties. Sixteen genes were significantly regulated by both chelators, while a further 50 genes were regulated by either ligand. Most of the genes identified in this study have not been previously described to be iron-regulated and are important for understanding the molecular and cellular effects of iron-deficiency. The MCF-7 cells were incubated with either control medium or this medium containing DFO (250 µM) or 311 (25 µM) for 24 h at 37oC. These concentrations were used since our previous studies demonstrated that under these conditions these chelators lead to up-regulation of iron-responsive genes such as the TfR1 after this incubation time.8 Moreover, the higher concentration of DFO was implemented due to its limited ability to permeate cell membranes. Total RNA was isolated from cells in 1 mL of TRIzol® reagent (Invitrogen). Samples were then prepared and hybridized to the Human Genome U133 Plus 2.0 430 2.0. The human GeneChip® U133 Plus 2.0 consists of greater than 47,000 transcripts and variants from over 38,500 well characterized human genes. On completion of hybridization and washing, microarray chips were scanned with the Affymetrix GeneChip® Scanner 3000 (Affymetrix).
Project description:The molecular role of iron in gene expression remains poorly characterized. Moreover, the alterations in global gene expression after iron chelation remains unclear and are important to assess for understanding the molecular pathology of iron-depletion and the biological effects of iron chelators. We assessed the effect on whole genome gene expression of two iron chelators (desferrioxamine and Dp44mT). These studies are important for understanding the molecular and cellular effects of iron-depletion. The DMS-53 cells were incubated with either control medium or this medium containing DFO (250 µM) or Dp44mT (25 µM) for 24 h at 37oC. These concentrations were used since our previous studies demonstrated that under these conditions these chelators lead to up-regulation of iron-responsive genes such as the TfR1 after this incubation time. Moreover, the higher concentration of DFO was implemented due to its limited ability to permeate cell membranes. Total RNA was isolated from cells in 1 mL of TRIzol® reagent (Invitrogen). Samples were then prepared and hybridized to the Human Genome U133 Plus 2.0 430 2.0. The human GeneChip® U133 Plus 2.0 consists of greater than 47,000 transcripts and variants from over 38,500 well characterized human genes. On completion of hybridization and washing, microarray chips were scanned with the Affymetrix GeneChip® Scanner 3000 (Affymetrix).
Project description:Neuroblastoma (NB) is the most frequent extracranial solid tumour of childhood. Clinical courses are highly variable, ranging from spontaneous regression/maturation to rapid progression despite intensive multimodal therapy. The estimation of 5-year event free survival in high-risk patients of only about 40 % stresses an importance of novel therapeutic strategies. A number of iron chelators have demonstrated marked in vitro and in vivo anti-tumor activity and are currently being developed as novel anti-cancer agents. Therefore, the potential antitumor effect of iron chelators in NB cancer was investigated. Among the compounds tested, ciclopirox olamine (CPX) was shown to be one of the most effective intracellular iron chelators in NB cells. To unveil the molecular mechanisms underlying the effects of CPX on viability of NB cells, microarray analysis was performed in CHP134 control cells and cells treated with 5 µM CPX for 90 minutes. Inclusion of both total RNA (reflecting transcriptional status of the cells) and polysomal RNA (approximating the proteomic representation of the cells) provided us with a deeper understanding of changes in the cells upon CPX treatment. Keywords: ciclopirox olamine, iron chelator, neuroblastoma, translatome profiling, transcriptome profiling. Keywords: ciclopirox olamine, iron chelator, neuroblastoma, translatome profiling, transcriptome profiling, polysomal profiling, polysomal RNA, translational control, translational profiling, polysome profiling
Project description:Neuroblastoma (NB) is the most frequent extracranial solid tumour of childhood. Clinical courses are highly variable, ranging from spontaneous regression/maturation to rapid progression despite intensive multimodal therapy. The estimation of 5-year event free survival in high-risk patients of only about 40 % stresses an importance of novel therapeutic strategies. A number of iron chelators have demonstrated marked in vitro and in vivo anti-tumor activity and are currently being developed as novel anti-cancer agents. Therefore, the potential antitumor effect of iron chelators in NB cancer was investigated. Among the compounds tested, ciclopirox olamine (CPX) was shown to be one of the most effective intracellular iron chelators in NB cells. To unveil the molecular mechanisms underlying the effects of CPX on viability of NB cells, microarray analysis was performed in CHP134 control cells and cells treated with 5 µM CPX for 24 hours. Inclusion of both total RNA (reflecting transcriptional status of the cells) and polysomal RNA (approximating the proteomic representation of the cells) provided us with a deeper understanding of changes in the cells upon CPX treatment. Keywords: ciclopirox olamine, iron chelator, neuroblastoma, translatome profiling, transcriptome profiling, polysomal profiling, polysomal RNA, translational control, translational profiling, polysome profiling