Distinct roles of PARP-1 and PARP-2 in c-Myc-driven B cell Lymphoma in mice
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ABSTRACT: To study the implication of PARP-1 deficiency or PARP-2 deficiency in the development of c-Myc overexpression-induced B lymphomas, we have studied by RNAseq the gene expression profile in pre-B cells isolated from bone marrow of mice that overexpress c-Myc in their B lymphocytes (WT) and in those mice with PARP-1 (KO1) or PARP-2 (KO2) deficiency
Project description:This experiment is to examine the effect of PARP inhibitor and Myc shRNA knockdown on transcriptome profiles in MYC-amplified human GBM stem cells MGG4.
Project description:Transcriptional profiling Myc-driven lymphomas to determine pathways by which Wrn deficiency impairs tumor development Total RNA isolated from Eµ-Myc and Eµ-Myc Wrn Δhel/Δhel murine B-cell lymphomas (n=4)
Project description:Poly(ADP-ribose) polymerase-2 (PARP-2) is acknowledged as a DNA repair enzyme; however, recently metabolic properties had been attributed to it. Hereby, we examined the metabolic consequences of PARP-2 ablation in liver. Microarray analysis of PARP-2 knockdown HepG2 cells revealed the dysregulation of lipid and cholesterol metabolism genes. Induction of cholesterol biosynthesis genes stemmed from the enhanced expression of sterol-regulatory element binding protein (SREBP)-1. We revealed that PARP-2 is a suppressor of the SREBP-1 promoter, therefore ablation of PARP-2 induces SREBP-1 expression and consequently cholesterol synthesis. PARP-2-/- mice had higher SREBP-1 expression that was translated into enhanced hepatic and serum cholesterol levels. PARP-2 silencing was performed employing shPARP-2 (small hairpin) and scPARP-2 (scrambled) shRNA by lentiviral delivery (Sigma) using 40 MOI lentiviruses coding shRNA sequence against PARP-2.
Project description:Erythropoiesis is a tightly regulated process in which multipotential hematopoietic stem cells give rise to mature red blood cells. Here, we show that Parp-2 deficiency in mice leads to chronic anemia, despite increased EPO plasma levels, providing a novel role for Parp-2 in erythropoiesis. Loss of Parp-2 causes shortened red blood cells lifespan and impaired differentiation of erythroid cells. Transcriptomic analyses revealed the activation of the p53-dependent-DNA damage response pathways on Parp-2-deficient erythroblasts, triggering the expression of genes involved in cell cycle checkpoints and apoptosis. Accordingly, Parp-2-deficient erythroblasts shows G2/M cell cycle arrest and increased apoptosis.
Project description:SUMOylation is a post-translational modification of proteins that regulates these proteins’ localization, turnover or function. Aberrant SUMOylation is frequently found in cancers but its origin remains elusive. Using a genome-wide transposon mutagenesis screen in a MYC-driven B-cell lymphoma model, we identified the SUMO isopeptidase (or deconjugase) SENP6 as a tumor suppressor that links unrestricted SUMOylation to tumor development and progression. Notably, SENP6 is recurrently deleted in human lymphomas and SENP6 deficiency results in unrestricted SUMOylation. Mechanistically, SENP6 loss triggers release of DNA repair- and genome maintenance-associated protein complexes from chromatin thereby impairing DNA repair in response to DNA damages and ultimately promoting genomic instability. In line with this hypothesis, SENP6 deficiency drives synthetic lethality to PARP inhibition. Together, our results link SENP6 loss to defective genome maintenance and reveal the potential therapeutic application of PARP inhibitors in B-cell lymphoma.
Project description:Mex3a is an RNA binding protein of unknown function. To elucidate the contribution of Mex3a to tumoral heterogeneity, Mex3a KO organoids engineered by CRISPR were sequenced in three different conditions. Live organoids (DAPI negative) were sorted in Control, after 2 days of FOLFIRI and after 5 days of treatment. Two WT organoids (parental and a derived clone) and two KO (KO1 and KO2, two independent clones) were used for this experiment.