Project description:Oncocytic variants of follicular thyroid carcinomas show a near-homozygous genome. Remarkably, homozygosity of chromosome 7 has never been observed which suggests that retention of heterozygosity is essential for cells. We hypothesized that cell survival genes are genetically imprinted on either of two copies of chromosome 7 which thwarts loss of heterozygosity at this chromosome in cancer cells. We identified 6 genes on chromosome 7 which demonstrated allele-specific expression. Subsequent knockdown of gene expression showed that CALCR, COPG2, GRB10, KLF14, MEST and PEG10 were essential for cancer cell survival resulting in reduced cell proliferation, G1-phase arrest and increased apoptosis. We propose that imprinted cell survival genes provide a genetic basis for retention of chromosome 7 heterozygosity in cancer cells.
Project description:41 lung adenocarcinoma from never-smokers hybridized on Illumina SNP arrays on 13 HumanCNV370-Quadv3 chips. High-resolution array comparative genomic hybridization analysis of lung adenocarcinoma in 41 never smokers for identification of new minimal common regions (MCR) of gain or loss. The SNP array analysis validated copy-number aberrations and revealed that RB1 and WRN were altered by recurrent copy-neutral loss of heterozygosity.The present study has uncovered new aberrations containing cancer genes. The oncogene FUS is a candidate gene in the 16p region that is frequently gained in never smokers. Multiple genetic pathways defined by gains of MYC, deletions of RB1 and WRN or gains on 7p and 7q are involved in lung adenocarcinoma in never smokers. A 'Cartes d'Identite des Tumeurs' (CIT) project from the French National League Against Cancer (http://cit.ligue-cancer.net) 41 samples hybridized on Illumina SNP arrays. Submitter : Fabien PETEL petelf@ligue-cancer.net . Project leader : Pr Pierre FOURET pierre.fouret@psl.aphp.fr
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 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: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:Chromosome arm deletions are frequently observed in human cancers. Such large-scale aberrations may trigger phenotypes distinct from those that arise by loss of single genes. Using TALEN-based genomic engineering, we generated cell models with targeted 8p loss-of-heterozygosity (LOH) that mimics an 8p deletion commonly found in breast cancer patients. 8p LOH triggered up-regulation of the mevalonate pathway. The alterations in lipid metabolism led to increased metastatic potential and drug resistance of 8p-deleted cells that are in agreement with poorer survival rates of breast cancer patients harbouting 8p LOH. Our findings also suggest novel therapeutic strategies for treatment of 8p LOH tumors. RNASeq Analysis of two Wt 8p Cell clones vs two 8p LOH cell clones generated via TALEN Approach
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.