Project description:Murine or human cancer cells have high glutathione levels. Depletion of the elevated GSH inhibits proliferation of cancer cells. Molecular basis for this observation is little understood. In an attempt to find out the underlying mechanism, we reproduced these effects in transformed C3H10T1/2 and BALB/c 3T3 cells using diethyl maleate and studied cytogenomic changes in the whole mouse genome using spotted 8 × 60K arrays. Transformed cells revealed an increase in GSH levels. GSH depletion by DEM inhibited the growth of transformed cells. The non-cytotoxic dose of DEM (0.25 mM) resulted in GSH depletion, ROS generation, cell cycle arrest, apoptosis, decrease in anchorage independent growth, gene expression changes and activation of all three members of the MAPK family. Increase in intracellular GSH levels by GSHe countered the effect of DEM. These results support the physiological importance of GSH in regulation of gene expression for transformed cell growth restraint. This study is of interest in not only understanding the molecular biology of the transformed cells, but also in identifying new targets for development of gene therapy together with the chemotherapy.
Project description:Murine or human cancer cells have high glutathione levels. Depletion of the elevated GSH inhibits proliferation of cancer cells. Molecular basis for this observation is little understood. In an attempt to find out the underlying mechanism, we reproduced these effects in transformed C3H10T1/2 and BALB/c 3T3 cells using diethyl maleate and studied cytogenomic changes in the whole mouse genome using spotted 8 M-CM-^W 60K arrays. Transformed cells revealed an increase in GSH levels. GSH depletion by DEM inhibited the growth of transformed cells. The non-cytotoxic dose of DEM (0.25 mM) resulted in GSH depletion, ROS generation, cell cycle arrest, apoptosis, decrease in anchorage independent growth, gene expression changes and activation of all three members of the MAPK family. Increase in intracellular GSH levels by GSHe countered the effect of DEM. These results support the physiological importance of GSH in regulation of gene expression for transformed cell growth restraint. This study is of interest in not only understanding the molecular biology of the transformed cells, but also in identifying new targets for development of gene therapy together with the chemotherapy. Agilent one-color experiment; Organism: Mus musculus; Agilent Custom Mouse Whole Genome Mouse 8x60k gene expression designed by Genotypic Technology Private Limited; Labeling kit: Agilent Quick-Amp labeling Kit (p/n5190-0442).
Project description:The two-stage cell transformation assay is an in vitro model cell culture system to identify the ability of chemicals to act as initiators or promoters of cell transforma- tion and also to study the cellular and molecular mechanisms of chemically induced morphological and neoplastic cell transformation. The global gene expression profiles of 3- methylcholanthrene (MCA)+12-O-tetradecanoylphorbol-13- acetate (TPA)-transformed C3H/10T1/2 cells are not known. Therefore, we have investigated the global transcriptional profile of MCA+TPA-transformed C3H10T1/2 cells using an 8×60 k probe microarray. The study revealed a differential regulation of pathways and gene expressions. Multifold dysregulation was seen in pathways of cancer, phagosomal activity, and tumor cell microenvironment information pro- cessing systems, notably the neuroactive ligand–receptor in- teraction, actin cytoskeleton regulation, tight junction, axon guidance, and cell adhesion molecules. The genes FGF1, EIF4E1B, MAGI1,and GRIA3 showed upregulation; these encoded the pluripotent fibroblast growth factor, the transla- tion initiation factor, the tight junction scaffolding protein, and the antiapoptotic as well as the enhancer of proliferation and migration, respectively. The genes CXCL7/CXCL5/CXCL12, H2DMB1,and HSPA1A showed downregulation; these encoded the chemotactic agent protein, the protein involved
Project description:The two-stage cell transformation assay is an in vitro model cell culture system to identify the ability of chemicals to act as initiators or promoters of cell transforma- tion and also to study the cellular and molecular mechanisms of chemically induced morphological and neoplastic cell transformation. The global gene expression profiles of 3- methylcholanthrene (MCA)+12-O-tetradecanoylphorbol-13- acetate (TPA)-transformed C3H/10T1/2 cells are not known. Therefore, we have investigated the global transcriptional profile of MCA+TPA-transformed C3H10T1/2 cells using an 8M-CM-^W60 k probe microarray. The study revealed a differential regulation of pathways and gene expressions. Multifold dysregulation was seen in pathways of cancer, phagosomal activity, and tumor cell microenvironment information pro- cessing systems, notably the neuroactive ligandM-bM-^@M-^Sreceptor in- teraction, actin cytoskeleton regulation, tight junction, axon guidance, and cell adhesion molecules. The genes FGF1, EIF4E1B, MAGI1,and GRIA3 showed upregulation; these encoded the pluripotent fibroblast growth factor, the transla- tion initiation factor, the tight junction scaffolding protein, and the antiapoptotic as well as the enhancer of proliferation and migration, respectively. The genes CXCL7/CXCL5/CXCL12, H2DMB1,and HSPA1A showed downregulation; these encoded the chemotactic agent protein, the protein involved Total mRNA was isolated from the control as well as the MCA+TPA-transformed C3H/10T1/2 cells and complemen- tary RNA (cRNA) was prepared from mRNA (1 M-NM-<g). One- color microarray processing was performed. Acceptable qual- ity of the total RNA sample was ascertained by its electropho- resis trace and integrity assay using a Bioanalyzer which profiled RNA by RIN interpretation. The T7 promoter-based linear amplification was used to generate labeled complemen- tary RNA to amplify target material and incorporate cyanine 3-labeled CTP using AgilentM-bM-^@M-^Ys low-input RNA linear amplifi- cation kit one color (cat no. 5188-5339). The fluorescence- labeled cRNA samples were hybridized onto a Genotypic- designed Custom Whole Genome Mouse 8x60k slide (AMADID no. 26986) in duplicate using AgilentM-bM-^@M-^Ysinsitu hybridization kit (no. 5184-3568). Hybridization was carried out in AgilentM-bM-^@M-^Ys Surehyb Chambers at 65M-BM-0C for 16 h. The hybridized slides were washed using Agilent Gene Expression wash buffers (part no. 5188-5327). Fluorescence data were collected using an Agilent Microarray Scanner (G2567AA) and analyzed with program Gene Spring GX, version 11.5 (Agilent Technologies, Bangalore, India). Significantly dysregulated genes were identified. Statistical t test p value was calculated based on volcano plot using Gene spring GX Software.
Project description:Dysregulation of pathways involved in the processing of cancer and microenvironment information in MCA+TPA transformed C3H/10T1/2 cells
Project description:In this study, we have investigated the changes in transformed cells that occur after GSH depletion and may be critical to accentuate the attenuation of carcinogenesis. The in vitro carcinogenesis method and GSH depletor Phorone (PHO) were used. We found that exposure of transformed C3H10T1/2 cells to PHO (2mM) caused attenuation of transformed cell growth as seen in soft agar assay. Loss of cellular GSH content, increase in intracellular ROS generation, and DNA strand break formation also occurred. A microarray based study using 8x60k oligonucleotide array in duplicate revealed changes in global gene expression profile. Our study has identified changes in expression of many genes that may contribute in abatement of carcinogenesis.
Project description:Glucose is the most important metabolic substrate of the retina and maintenance of nor-moglycemia is an essential challenge for diabetic patients. Glycemic excursions could lead to cardiovascular disease, nephropathy, neuropathy and retinopathy. We recently showed that hy-poglycemia induced retinal cell death in mouse via caspase 3 activation and glutathione (GSH) decrease. Ex vivo experiments in 661W photoreceptor cells confirmed the low-glucose induction of death via superoxide production and activation of caspase 3, which was concomitant with a decrease of GSH content. We evaluate herein retinal gene expression 4 h and 48 h after insulin-induced hypoglycemia. Microarray analysis demonstrated clusters of genes whose expression is modified by hypoglycemia and we discuss the potential implication of those genes in retinal cell death. In addition, we highlight, by gene set enrichment analysis, three important pathways, including KEGG lysosomes, KEGG GSH metabolism and REACTOME apoptosis pathways. We tested the effect of recurrent hypoglycemia (three successive 5h periods of hypoglycemia separated by 48 h recovery) on retinal cell death. Interestingly, exposure to multiple hypoglycemic events prevents retinal cell death and GSH decrease, or adapts the retina to external stress by restoring GSH level comparable to control situation. We hypothesize that scavenger GSH is a key compound in this apoptotic process, and maintaining “normal” GSH level, as well as a strict glycemic control, may represent a therapeutic challenge in order to avoid side effects of diabetes, especially diabetic retinopathy.
Project description:Neural regeneration and neuroprotection represent promising therapeutic approaches for neurodegenerative disorders like Alzheimer's disease (AD) or glaucoma. However, the molecular mechanisms that lead to neuroprotection are not clearly understood. One of the promising candidates to revive physiological function is neuroserpin (Serpini1), a serine protease inhibitor expressed by neurons which selectively inhibits extracellular tissue-type plasminogen activator (tPA)/plasmin and plays a neuroprotective role during ischemic brain injury. Abnormal function of this protein has been implicated in stroke, glaucoma, AD and FENIB. Here we report proteome changes by neuroserpin modulation in brains, retinas, and optic nerves from 12-month C57BL6/J neuroserpin deficient mice (NeuS-/-).
Project description:Nitric oxide (NO) can stabilize mRNA by activating p38 mitogen-activated protein kinase (MAPK). Here, transcript stabilization by NO was investigated in human THP-1 cells using microarrays. After LPS pre-stimulation, cells were treated with actinomycin D and then exposed to NO without or with the p38 MAPK inhibitor SB202190. The decay of 220 mRNAs was affected; most were stabilized by NO. Unexpectedly, SB202190 often enhanced rather than antagonized transcript stability. NO activated p38 MAPK and Erk1/2; SB202190 blocked p38 MAPK, but further activated Erk1/2. PCR confirmed that NO and SB202190 could additively stabilize mRNA, an effect abolished by Erk1/2 inhibition. In affected genes, these responses were associated with CU-rich elements (CURE) in 3ï¢ un-translated regions. NO stabilized the mRNA of a CURE-containing reporter gene, while repressing translation. Dominant-negative Mek1, an Erk1/2 inhibitor, abolished this effect. NO similarly stabilized, but blocked translation of MAP3K7IP2, a natural CURE-containing gene. NO increased hnRNP translocation to the cytoplasm and binding to CURE. Over-expression of hnRNP K, like NO, repressed translation of CURE-containing mRNA. These findings define a sequence-specific mechanism of NO-triggered gene regulation that stabilizes mRNA, but represses translation. Experiment Overall Design: THP-1 cells were first stimulated with LPS (1 µg/ml) for 4 h to boost transcript levels. After 30 min treatment with ActD (2.5 µg/ml), a transcription inhibitor, in the absence or presence of p38 MAPK inhibitor SB (0.1 µM), cells were then further incubated for 0-180 min with 400 µM of GSNO or GSH control (N = 4). Total RNA at different time points (0, 45, 90 and 180 min) was extracted, labeled and hybridized to human U133A microarrays, which were then scanned using Agilent GeneArray Scanner. Affymetrix MAS5 signal values were analyzed and first normalized to the 97th percentile, a value corresponding to the expression level of the 678th most intense probeset on the array. This normalization strategy assumed that the most intense probesets corresponded to mRNA species which were most stable and were generally unaffected by the treatments studied here. Then logarithmically transformed normalized data were subject to linear regression with respect to the 4 time points studied (0, 45, 90, 180 min following the start of incubation with GSH or GSNO), to estimate a slope corresponding to a first-order decay rate. The decay slope was calculated for each probeset, for each of the four conditions (GSH, GSNO, SB/GSH and SB/GSNO) using an Analysis of Covariance (ANCOVA), constraining the time 0 expression value to be identical for the pair of conditions without SB and the pair with SB, as necessitated by the design of the experiment. Further, since the experiment was replicated in 4 distinct batches, a blocked ANCOVA was utilized. The analysis results were then used to select genes which decayed, and whose decay rate changed following treatment. The p-value for a one-way, four level ANCOVA was calculated and used to compute a false discovery rate (FDR). The probesets with the lowest p-values, corresponding to a FDR of 10%, were selected and annotated based on information presented by Affymetrix at the NetAffx web-site as of April 12, 2004.
Project description:Burkholderia caribensis MBA4 is able to metabolize monochloroacetate (MCA) as sole carbon and energy source for growth. A haloacid dehalogenase is mainly responsible for the cleavage of the carbon-halogen bond. The MCA will be hydrolyzed to glycolate which would be further transformed to glyoxylate by glycolate oxidase. In order to identify inducible genes involved in mineralization of MCA, transcriptomes of MBA4 cells grown on MCA, glycolate or pyruvate were determined using RNA-seq technology. After trimming and filtering, clean data of each transcriptome were mapped to an annotated genome of MBA4 and the expression values of various genes were calculated and compared. The results showed that there are specific sets of genes being induced by MCA and not by its dehalogenation product glycolate. Noticeably, among three glycolate oxidase operons identified in the genome their expressions were found to be varied individually in response to MCA, glycolate and pyruvate. One of the operons was minimally expressed no matter what was the growth substrate. Another operon was inducible both by MCA and glycolate. This is expected and which suggested that this operon is most likely responds to the presence of glycolate. The third operon contains the structural genes, glcDEF, for glycolate oxidase, glcG, for an uncharacterized protein associated with glycolate metabolism, and glcB, for malate synthase G. This operon was inducible by MCA only and not by glycolate nor pyruvate.