Project description:Many anti-cancer drugs induce DNA breaks to eliminate tumor cells. The anthracycline topoisomerase II inhibitors can also evict histones. We performed a genome-wide high-resolution mapping of chemotherapeutic effects of various topoisomerase I and II inhibitors. We show that different drugs target different types of chromatin for induction of DNA damage and histone eviction. Topoisomerase inhibitors topotecan and etoposide similarly target transcriptionally active chromatin for DNA damage. Daunorubicin induces DNA breaks and evicts histones in active chromatin, thus quenching local DNA damage response. The analog aclarubicin evicts histones in H3K27me3-marked heterochromatin. These results can guide rational treatment decisions regarding these genome manipulating anti-cancer drugs. FAIRE-seq and g-H2AX ChIP-seq were performed on K562 cells after drug exposure
Project description:Many anti-cancer drugs induce DNA breaks to eliminate tumor cells. The anthracycline topoisomerase II inhibitors can also evict histones. We performed a genome-wide high-resolution mapping of chemotherapeutic effects of various topoisomerase I and II inhibitors. We show that different drugs target different types of chromatin for induction of DNA damage and histone eviction. Topoisomerase inhibitors topotecan and etoposide similarly target transcriptionally active chromatin for DNA damage. Daunorubicin induces DNA breaks and evicts histones in active chromatin, thus quenching local DNA damage response. The analog aclarubicin evicts histones in H3K27me3-marked heterochromatin. These results can guide rational treatment decisions regarding these genome manipulating anti-cancer drugs.
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 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: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. Two-condition experiment, Normoxic MSCs vs. Hypoxic MSCs.