Project description:Heme Oxygenase-1 (HO-1) is expressed in many cancers and influences the growth, survivall and metastasis of tumors, however, the molecular mechanisms remains largely unknown. To identify a common mechanism of action of HO-1 in cancer, we studied the global effect of HO-1 on the transcriptome of multiple tumors. Genome-wide expression profiling of HO-1 expressing versus HO-1 silenced cancer cells and a further data mining analysis of the preexisting expression database of 190 human tumors of 14 cancer types led us to identify 14 genes, the expression of which correlated firmly and universally with that of HO-1 (P < 0.001). These genes included regulators of cell plasticity and extracellular matrix remodeling (MMP2, ADAM8, TGFβ1, BGN, COL21A1, PXDN), signaling (CRIP2, MICB), amino acid transport and glycosylation (SLC7A1 and ST3GAL2), estrogen and phospholipid biosynthesis (AGPAT2 and HSD17B1), protein stabilization (IFI30) and phosphorylation (ALPPL2). PXDN, one of the genes being co-expressed with HO-1, was selected for further analysis. Immunofluorescence and western blotting confirmed positive correlation of PXDN with HO-1 levels in BeWo cancer cells as well as co-localization in invasive extravillous trophoblast cells of first trimester placenta. Loss of HO-1 in BeWo cells correlated with reduced cell adhesion to Collagen type I, Fibronectin and Laminin. The adhesion-promoting effects of HO-1 were dependent on PXDN expression, as loss of PXDN in HO-1 expressing BeWo cells led to reduced cell attachment to Laminin and Fibronectin coated wells. We used gene expression profiling to determine the genome-wide effect of HO-1 on the transcriptome of BeWo trophoblast cells. We specifically selected BeWo cells for our studies because these cells express HO-1 naturally. We knocked down endogenous HO-1 in BeWo cells using retroviral transduction with a micro-RNA adapted retroviral vector targeting human HO-1 sequence. RNA isolated from control (LMP) or miHO1 infected (miHO-1) cells was labeled and hybridized to human genome-wide gene level 1.0 ST arrays
Project description:Heme Oxygenase-1 (HO-1) is expressed in many cancers and influences the growth, survivall and metastasis of tumors, however, the molecular mechanisms remains largely unknown. To identify a common mechanism of action of HO-1 in cancer, we studied the global effect of HO-1 on the transcriptome of multiple tumors. Genome-wide expression profiling of HO-1 expressing versus HO-1 silenced cancer cells and a further data mining analysis of the preexisting expression database of 190 human tumors of 14 cancer types led us to identify 14 genes, the expression of which correlated firmly and universally with that of HO-1 (P < 0.001). These genes included regulators of cell plasticity and extracellular matrix remodeling (MMP2, ADAM8, TGFβ1, BGN, COL21A1, PXDN), signaling (CRIP2, MICB), amino acid transport and glycosylation (SLC7A1 and ST3GAL2), estrogen and phospholipid biosynthesis (AGPAT2 and HSD17B1), protein stabilization (IFI30) and phosphorylation (ALPPL2). PXDN, one of the genes being co-expressed with HO-1, was selected for further analysis. Immunofluorescence and western blotting confirmed positive correlation of PXDN with HO-1 levels in BeWo cancer cells as well as co-localization in invasive extravillous trophoblast cells of first trimester placenta. Loss of HO-1 in BeWo cells correlated with reduced cell adhesion to Collagen type I, Fibronectin and Laminin. The adhesion-promoting effects of HO-1 were dependent on PXDN expression, as loss of PXDN in HO-1 expressing BeWo cells led to reduced cell attachment to Laminin and Fibronectin coated wells.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs. One-condition experment, gene expression of 3A6
Project description:Invasion of cytotrophoblasts into uterine tissues is essential for placental development. To identify molecules regulating trophoblast invasion, mRNA signatures of purified villous (CTB, poor invasiveness) and extravillous (EVT, high invasiveness) trophoblasts isolated from first trimester human placentae and villous explant cultures, respectively, were compared using GeneChip analyses yielding 991 invasion/migration related transcripts. Several genes involved in physiological and pathologic cell invasion, including ADAM-12,-19,-28 as well as Spondin-2, were upregulated in EVT. Pathway prediction analyses identified several functional modules associated with either the invasive or the non-invasive trophoblast phenotype. One of the genes which were downregulated in the invasive mRNA pool, heme oxygenase-1 (HO-1), was selected for functional analyses. Real-time PCR analyses, Western blottting, and immunofluorescene of first trimester placentae and differentiating villous explant cultures demonstrated downregulation of HO-1 in invasive EVT as compared to CTB. Modulation of HO-1 expression in loss-of as well as gain-of function cell models (BeWo and HTR8/SVneo, respectively) demonstrated an inverse relationship of HO-1 expression with trophoblast migration in transwell and wound healing assays. Importantly, HO-1 expression led to an increase in protein levels and activity of the nuclear hormone receptor PPARgamma. Pharmacological inhibition of PPARgamma abrogated the inhibitory effects of HO-1 on trophoblast migration. Collectively, our results demonstrate that gene expression profiling of EVT and CTB can be used to unravel novel regulators of cell invasion. Accordingly, we identify heme oxygenase-1 as a negative regulator of trophoblast motility acting via upregulation of PPARgamma. Experiment Overall Design: To identify genes potentially regulating cell invasion trophoblast cells of early human gestation with distinct invasive properties were profiled. Experiment Overall Design: Distinct gene expression signatures of highly invasive EVT (n = 6) and poorly invasive CTB (n = 5) of different first trimester placentae using Affymetrix U133A GeneChips interrogating >20,000 genes were determined.
Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes