DNA microarray analysis for HepG2 cells exposed to arsenic trioxide
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ABSTRACT: DNA microarray analysis revealed that the genes related to cell cycle regulation were significantly induced at non- and sub-lethal concentrations (i.e., 0.05-6 µM), while the common feature of heavy metal toxicity such as oxidative damage and following increase in glutathione, heat shock proteins, and metallothionein were confirmed at high concentrations (i.e., 6-40 µM). The concentration dependent modulation of gene expression (induction of cell cycle genes, induction of cell cycle arrest genes and apoptotic genes) following exposure to arsenic was further supported by acceleration of cell proliferation, ROS generation, and cytotoxicity. Furthermore, three cell cycle genes (i.e., CDC25B, UBE2C, and PTTG1) were proposed as marker genes of inorganic arsenic exposure. Those results indicated the potential pro-carcinogenic actions of inorganic arsenic occur in environmentally relevant exposures (as low as 0.07 µM).
Project description:DNA microarray analysis revealed that the genes related to cell cycle regulation were significantly induced at non- and sub-lethal concentrations (i.e., 0.05-6 M-BM-5M), while the common feature of heavy metal toxicity such as oxidative damage and following increase in glutathione, heat shock proteins, and metallothionein were confirmed at high concentrations (i.e., 6-40 M-BM-5M). The concentration dependent modulation of gene expression (induction of cell cycle genes, induction of cell cycle arrest genes and apoptotic genes) following exposure to arsenic was further supported by acceleration of cell proliferation, ROS generation, and cytotoxicity. Furthermore, three cell cycle genes (i.e., CDC25B, UBE2C, and PTTG1) were proposed as marker genes of inorganic arsenic exposure. Those results indicated the potential pro-carcinogenic actions of inorganic arsenic occur in environmentally relevant exposures (as low as 0.07 M-BM-5M). In this study, we examined the gene expression alteration in HepG2 cells exposed to arsenic trioxide (5 nM to 40 M-BM-5M as As2O3 for 48 hours) by DNA microarray with 8795 human genes. HepG2 cells were also exposed to M-NM-5-caprolactam as a reference of non carcinogen since it is the only chemical categorized in IARCM-bM-^@M-^Ys group 4 (Probably Not Carcinogenic). MQ water was used as control. For replicate, three dishes were prepared for each sample and individually treated in parallel.
Project description:The purpose of this study is to search for aberrant genes in HaCaT keratinocytes after chronic exposure to arsenic trioxide. The objective of the investigation was to discover the mechanism of arsenic carcinogenicity in human epidermal keratinocytes. We hypothesize that a combined strategy of DNA microarray, qRT-PCR and gene function annotation will identify aberrantly expressed genes in HaCaT keratinocyte cell line after chronic treatment with arsenic trioxide. HaCaT cells were chronically exposed to 0.5µg/mL arsenic trioxide (As2O3) up to 22 passages and RNA was extracted. Microarray data analysis identified 14 up-regulated genes and 21 down-regulated genes in response to arsenic trioxide
Project description:Arsenic is reportedly a biphasic inorganic compound for its toxicity and anticancer effects in humans. Recent studies have shown that certain arsenic compounds including arsenic hexoxide_x000D_ (AS4O6; hereafter, AS6) induce programmed cell death and cell cycle arrest in human cancer cells and murine cancer models. However, the mechanisms by which AS6 suppresses cancer cells are incompletely understood. In this study, we show markedly differential effects of AS6 on cytotoxicity and gene expression in human mammary epithelial normal cells (HUMEC) and Michigan Cancer Foundation 7 (MCF7), a human mammary epithelial cancer cell line. AS6 selectively arrests cell growth and induces cell death in MCF7 cells without affecting the growth of HUMEC in a dose-dependent_x000D_ manner. AS6 alters the transcription of a large number of protein-coding genes in MCF7 cells, but much fewer genes in HUMEC. Importantly, we found that the cell proliferation, cell cycle, and DNA repair pathways are significantly suppressed whereas cellular stress response and apoptotic pathways_x000D_ increase in AS6-treated MCF7 cells. Together, we provide the first evidence of differential effects of AS6 on normal and cancerous breast epithelial cells, suggesting that AS6 at moderate concentrations induces cell cycle arrest and apoptosis through modulating genome-wide gene expression, leading to compromised DNA repair and increased genome instability selectively in human breast cancer cells
Project description:The purpose of this study is to search for aberrant genes in HaCaT keratinocytes after chronic exposure to arsenic trioxide. The objective of the investigation was to discover the mechanism of arsenic carcinogenicity in human epidermal keratinocytes. We hypothesize that a combined strategy of DNA microarray, qRT-PCR and gene function annotation will identify aberrantly expressed genes in HaCaT keratinocyte cell line after chronic treatment with arsenic trioxide. HaCaT cells were chronically exposed to 0.5M-BM-5g/mL arsenic trioxide (As2O3) up to 22 passages and RNA was extracted. Microarray data analysis identified 14 up-regulated genes and 21 down-regulated genes in response to arsenic trioxide Two experimental groups: 1. The treatment group was sub-cultured up to passage 22 to establish a chronic exposure state. 2. The passage control group was also sub-cultured up to 22 passages but with no exposure to arsenic trioxide. 4 technical replicates with 3 replicates making a total of 8X3 =24 samples HaCat Cell untreated (passage control): 1. H1_H001, H1_H002, H1_H003 2. H2_ H004, H2_H005, H2_H006 3. H3_ H007, H3_H008, H3_H009 4. H4_ H010, H4_H011, H4_H012 HaCat Cell treated with 0.5M-BM-5g/ml of arsenic trioxide: 5. A1_H013, A1_H014, A1_H015 6. A2_H016, A2_H017, A2_H018 7. A3_H019, A3_H020, A3_H021 8. A4_H022, A4_H023, A4_H024 Cell Type: Human Skin Keratinocyte: 1.5 M-CM-^W105 HaCaT cells were cultured in 7.5 ml of complete DMEM containing 10% Fetal Bovine Serum (FBS) and 1% penicillin, streptomycin in T-25 culture plate. Cells were incubated in a humidified atmosphere with 5% CO2 at 37 M-BM-:C. The treatment groups were exposed to 0.5M-BM-5g/mL As2O3 (equivalent to LC 0.5), and passaged at 90% confluent. Total RNA was extracted from 4 technical replicates of unexposed HaCaT cells and HaCaT cells chronically exposed to arsenic trioxide up to passage 22 using RNA STAT-60 (TEL-TEST, INC, Friendswood, TX, USA).
Project description:Arsenic is a human toxin and carcinogen commonly found as a contaminant in drinking water. Arsenite (AsIII) is the most toxic inorganic form, but recent evidence indicates that the metabolite monomethylarsonous acid (MMAIII) is even more toxic. We have used a chemical genomics approach to identify the genes that modulate the cellular toxicity of MMAIII and AsIII in the yeast Saccharomyces cerevisiae. Functional profiles provided evidence of the requirement of highly-conserved biological processes in the response against both arsenicals including tubulin folding, DNA double-strand break repair and chromatin modification. At the equitoxic doses of 150 µM MMAIII and 300 µM AsIII, genes related to glutathione were essential only for resistance to the former, suggesting a higher potency of MMAIII to disrupt glutathione metabolism than AsIII. Treatments with MMAIII induced an increase in glutathione levels, which correlated to the requirement of genes from the sulfur and methionine metabolic pathways. Many of the identified yeast genes have orthologs in humans that could potentially modulate arsenic toxicity in a similar manner as their yeast counterparts.
Project description:Arsenic is a potent environmental toxin and a cause of numerous health problems. Most studies have assumed that arsenic-induced changes in mRNA levels result from effects on gene transcription. The influence of arsenic on post-transcriptional regulation, another important locus of gene expression control, has remained largely unexplored. To evaluate the prevalence of changes in mRNA stability in response to arsenic in human fibroblasts, we used microarray analyses to determine changes in steady state mRNA levels, and their decay rates, following 24 hour exposure to non-cytotoxic concentrations of sodium arsenite (1 µM). We conclude that arsenite modification of mRNA stability is relatively uncommon, but in some instances can result in significant changes in gene expression.
Project description:Drug concentrations were selected to halt cell cycle progression without affecting cell viability: 94T778 10 µM, A375, SKMEL28 and AU565 4 µM, SKBR3 0.8 µM. The pharmacologic inhibition of MTOR repressed expression of the homologous recombination (HR) and Fanconi Anemia (FA) pathways, and selectively high-fidelity but not error-prone DNA polymerases in all cancer cell lines sequenced
Project description:Gene expression analysis of prostate spheres and orgnoids in response to the inorganic arsenic exposure, to provide insight into the molecular mechenisms invovled in arsenic-induced homeostasis dysregulation of prostate stem-progenitor cells.
Project description:Present experinment depicts the global gene expression profile of adult zebrafish to understand the conserved molecular snapshot beyond dose dependency and tissue specificity. The data provides ample insight of changes in gene expression leading to arsenic toxicity in vivo. Several aspects of arsenic toxicity are further validated by qPCR.