Arsenic metalloid is a double-edge sword. On the one hand it is a very toxic and powerful carcinogen, and on the other it has been successfully used in the treatment of acute promyelocytic leukemia. In order to prevent the deleterious effects caused by arsenic compounds, almost all living organisms have developed mechanisms to eliminate it. In this study genome-wide response of S. cerevisiae to arsenic shows that this metal interferes with genes involved in the iron homeostasis including those encoding proteins that function in iron uptake, incorporation into FeS clusters, and more. In addition our data indicate that Yap1 transcriptionally controls the iron homeostasis regulator AFT2 as well as its direct target, MRS4. Most importantly in response to arsenate exposure Yap1 strongly regulates the expression of several genes involved in the Fe-S proteins biosynthesis, namely NBP35 and YFH1. Interestingly mRNA levels encoding Fet3, Ferro-O2-oxidoreductase required for high-affinity iron uptake, are drastically destabilized upon arsenic exposure. Such destabilization is due to the 5 to 3 exonuclease Xrn1 localized in the P Bodies. Moreover FET3 mRNA decay is not mediated by Cth2 and is independent on the formation of ROS responsible for the toxic effects of arsenic compounds. Strikingly, in presence of arsenate fet3 mutant shows resistance over the wild-type which leads us to suggest that Fet3 has a role in arsenic toxicity. Unexpectedly arsenic treatment seems to activate the non-reductive iron uptake in order to maintain the cellular iron homeostasis. Furthermore our genetic, biochemical, and physiological analysis demonstrate that aft1 mutant is sensitive to arsenic compounds and such phenotype is reversible upon addition of iron. We also show that arsenic exposure induces iron deficiency in aft1 mutant. In conclusion this work shows for the first time that arsenic, a chemotherapy drug used to treat a specific type of acute promyelocytic leukemia (APL), disrupts iron homeostasis and our results suggest that this disruption is independent on ROS generation. Finally we provide preliminary data confirming that such disruption also takes place in mammalian cells, an observation that can be very relevant in term of clinical applications.
Arsenic stress elicits cytosolic Ca(2+) bursts and Crz1 activation in Saccharomyces cerevisiae.
Time
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Epigenetic drug combination induces genome-wide demethylation and altered gene expression in neuro-ectodermal tumor-derived cell lines.
Sex, Specimen part, Disease, Cell line, Treatment
View SamplesAbstract: Epigenetic alterations are a fundamental aspect of cancer cells, and epigenetic drugs are currently used in clinical practice for hematological malignancies. Pediatric neuro-ectodermal tumors originate from neural crest cells and show epigenetic defects of apoptotic pathways, which makes the introduction of epigenetic drugs in this patient category logical. However, the young age of these patients is accompanied by ongoing developmental processes which are regulated epigenetic mechanisms, and prompted us to study molecular effects of nanomolar dosage epigenetic drugs in neuro-ectodermal tumor cell lines. Combination treatment of 5-aza-2`-deoxicytidine (DAC) and Trichostatin A (TSA) at nanomolar dosages resulted in wide-spread demethylating effects in 17 NBL and 5 PNET cell lines in vitro. This widespread demethylation had large effects on gene-expression profiles. In NBL cell lines, almost every cellular pathway (193/200) investigated demonstrated altered expression upon treatment, and resulted in upregulation of known epigenetically regulated genes such as X-chromosomal, tissue-specific, and a few imprinted genes. Integration analysis of CpG island methylation array data and whole genome gene expression data identified 30 genes potentially upregulated by gene promoter demethylation. Homeobox genes frequently showed demethylation in both short term (72 hours) and long term cultures (3 months) of NBL lines. Continuous treatment with epigenetic drugs resulted in low rates of proliferation. The low rate of proliferation that might explain limited consecutive demethylation upon prolonged exposure. In conclusion, genome-wide methylation and gene expression changes are induced DAC and TSA treatment at nanomolar dosages. These effects affected more than 97% of cellular pathways investigated. Further studies towards the effects of epigenetic drug combinations are advised before being applied in clinical trials for pediatric patients.
Epigenetic drug combination induces genome-wide demethylation and altered gene expression in neuro-ectodermal tumor-derived cell lines.
Sex, Specimen part, Cell line
View SamplesSubjects with incidental Lewy body disease (iLBD) may represent the premotor stage of Parkinsons disease (PD). To identify molecular mechanisms underlying neuronal dysfunction and alpha--synuclein pathology in the premotor phase of PD, we investigated the transcriptome of post-mortem substantia nigra (SN) of iLBD, PD donors and age-matched controls with Braak alpha--synuclein stage ranging from 0-6. In Braak alpha--synuclein stages 1 and 2, we observed deregulation of pathways linked to axonal degeneration, unfolded protein response (UPR), immune response and endocytosis, including axonal guidance signaling, protein kinase A signaling, mTOR signaling, EIF2 signaling and clathrin-mediated endocytosis. In Braak stages 3 and 4, we observed a deregulation in pathways involved in protein translation and cell survival, including mTOR and EIF2 signaling. In Braak stages 5 and 6, we observed deregulation of pathways such as dopaminergic signaling, axonal guidance signaling and thrombin signaling. Throughout the progression of PD pathology, we observed a deregulation of mTOR, EIF2 and regulation of eIF4 and p70S6K signaling in the SN. This implicates that molecular mechanisms related to UPR, axonal dysfunction, endocytosis and immune response are an early event in PD pathology, and may hold the key to altering the disease progression in PD.
Evidence for Immune Response, Axonal Dysfunction and Reduced Endocytosis in the Substantia Nigra in Early Stage Parkinson's Disease.
Specimen part, Disease, Disease stage
View SamplesThe data contained in this record are used to differentiate between the effects of IFN-a and IFN-b on 48h cultures of the ex vivo pbmcs of ATL patients, using Affymetrix microarrays (HuGene 1.0).
IFN-β induces greater antiproliferative and proapoptotic effects and increased p53 signaling compared with IFN-α in PBMCs of Adult T-cell Leukemia/Lymphoma patients.
Specimen part, Subject
View SamplesThe majority of sporadic colorectal cancer cases are initiated by mutations in the APC tumor suppressor gene leading to constitutive activation of the Wnt/b-catenin signaling pathway and adenoma formation. Several pre-clinical models carrying germline mutations in the endogenous mouse Apc tumor supressor gene have been generated and their phenotype characterized. The predisposition of these mouse models to multiple intestinal adenomas closely resembles the FAP phenotype at the molecular, cellular and phenotypic level and may prove valuable to elucidate the molecular and cellular mechanisms underlying colorectal tumorigenesis. The goal of this study is to establish an expression signature characteristic of intestinal tumors characterized by the inactivation of Apc.
Cross-species comparison of human and mouse intestinal polyps reveals conserved mechanisms in adenomatous polyposis coli (APC)-driven tumorigenesis.
Sex, Age, Specimen part
View SamplesAcute Lymphoblastic Leukemia (ALL) in infants (<1 year) is characterized by a poor prognosis and a high incidence of MLL translocations. Several studies demonstrated the unique gene expression profile associated with MLL-rearranged ALL, but generally small cohorts were analyzed as uniform patient groups regardless of the type of MLL translocation, while the analysis of translocation-negative infant ALL remained unacknowledged.
Gene expression profiling-based dissection of MLL translocated and MLL germline acute lymphoblastic leukemia in infants.
Sex, Age, Specimen part
View SamplesGata2, a zinc finger TF, is essential for the generation and survival of HSCs in the embryo and has been implicated in the pathogenesis of AML, yet the requirement for Gata2 in adult HSCs and LSCs remains unclear. Using a conditional mouse model where Gata2 was deleted specifically in hematopoietic cells, we show that knockout of Gata2 leads to a rapid and complete cell-autonomous loss of adult HSCs. In Meis1a/Hoxa9 driven AML, deletion of Gata2 impedes maintenance and self-renewal of LSCs. We then performed RNA-seq from sorted control and Gata2 KO LSCs (CD45.2+ c-Kit+) after pIpC treatment in transplanted mice. Overall design: Wild Type and Gata2-/- Meis1a/Hoxa9 LSCs were harvested from mice 24 days after pIpC administration
Gata2 as a Crucial Regulator of Stem Cells in Adult Hematopoiesis and Acute Myeloid Leukemia.
Cell line, Subject
View SamplesGata2, a zinc finger TF, is essential for the generation and survival of HSCs in the embryo and has been implicated in the pathogenesis of AML, yet the requirement for Gata2 in adult HSCs and LSCs remains unclear. Using a conditional mouse model where Gata2 was deleted specifically in hematopoietic cells, we show that knockout of Gata2 leads to a rapid and complete cell-autonomous loss of adult HSCs. We then performed RNA-seq in sorted HSCs (LSK CD48- CD150+) from control and Gata2+/fl;Vav-iCre+ 8-to-10-week old mice. Overall design: Wild Type and Gata2+/- HSCs were harvested from 8-to-10-week old mice
Gata2 as a Crucial Regulator of Stem Cells in Adult Hematopoiesis and Acute Myeloid Leukemia.
Cell line, Subject
View SamplesWe identified MDA-9/Syntenin (8q12) as a key component of HNSCC differentiation and angiogenesis.
MDA-9/Syntenin regulates differentiation and angiogenesis programs in head and neck squamous cell carcinoma.
Cell line
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