Project description:Smoothened (SMO)-inhibitors recently entered clinical trials for sonic-hedgehog driven medulloblastoma (SHH-MB). Clinical response appears highly variable. To understand the mechanism(s) of primary resistance and to identify pathways co-operating with aberrant SHH-signaling, we sequenced a large cohort of SHH-MBs across all age groups by sequencing, DNA methylation and expression profiling. Our data show that most adults but only half of the pediatric patients with SHH-MB will respond to SMO inhibition as predicted by molecular analysis of the primary tumor and tested in the SHH-xenografts, demonstrating that the next generation of SMO-inhibitor trials should be based on these predictive biomarkers. To further dissect the biological differences between the different age groups within SHH medulloblastomas, we looked at the DNA methylation profiles of SHH medulloblastoma samples. We investigated the DNA methylation profiles of 46 SHH medulloblastomas across all age groups using the Illumina 450k methylation array.
Project description:Smoothened (SMO)-inhibitors recently entered clinical trials for sonic-hedgehog driven medulloblastoma (SHH-MB). Clinical response appears highly variable. To understand the mechanism(s) of primary resistance and to identify pathways co-operating with aberrant SHH-signaling, we sequenced a large cohort of SHH-MBs across all age groups by sequencing, DNA methylation and expression profiling. Our data show that most adults but only half of the pediatric patients with SHH-MB will respond to SMO inhibition as predicted by molecular analysis of the primary tumor and tested in the SHH-xenografts, demonstrating that the next generation of SMO-inhibitor trials should be based on these predictive biomarkers. To further dissect the biological differences between the different age groups within SHH medulloblastomas, we looked at the DNA methylation profiles of SHH medulloblastoma samples. We investigated the DNA methylation profiles of 83 SHH medulloblastomas across all age groups using the Illumina 450k methylation array.
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: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. Two-condition experiment, KP MSCs vs. 3A6 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:SPO11-promoted DNA double-strand breaks (DSBs) formation is a crucial step for meiotic recombination, and it is indispensable to detect the broken DNA ends accurately for dissecting the molecular mechanisms behind. Here, we report a novel technique, named DEtail-seq (DNA End tailing followed by sequencing), that can directly and quantitatively capture the meiotic DSB 3’ overhang hotspots at single-nucleotide resolution.