Project description:HS-10502 is a Poly(ADP-ribose) polymerase 1 (PARP1)-specific selective inhibitor. The purpose if this study is to assess the safety, tolerability, pharmacokinetics (PK), and efficacy of HS-10502 in subjects with homologous recombination repair (HRR) gene mutant or homologous recombination deficiency (HRD) positive advanced solid tumors.
Project description:Poly(ADP-ribose) polymerase-1 (PARP-1) and poly(ADP-ribose) glycohydrolase (PARG) are enzymes that modify target proteins in the nucleus by the addition and removal, respectively, of ADP-ribose polymers. Although a role for PARP-1 in gene regulation has been well established, the role of PARG is less clear. To investigate how PARP-1 and PARG coordinately regulate global patterns of gene expression, we used short hairpin RNAs (shRNAs) to stably knockdown PARP-1 or PARG in MCF-7 cells, followed by expression microarray analyses.
Project description:The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that mediates the toxic effects of the environmental contaminant, dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD). Dioxin causes a diverse range of toxic responses, including hepatic damage and lethal wasting syndrome; however, the mechanisms of dioxin-induced toxicity are still unknown. Here we show that the loss of TCDD-inducible poly(ADP-ribose) polymerase (TIPARP; ARTD14), an ADP-ribosyltransferase and AHR repressor, increases sensitivity to dioxin-induced toxicity and lethality. Tiparp-/- mice treated with a single injection of 100 mg/kg dioxin display an accelerated lethal wasting syndrome with no Tiparp-/- mice surviving beyond day 5; all Tiparp+/+ mice survived up to 30 days post treatment. Tiparp-/- mice displayed dramatic increases in liver steatosis and hepatotoxicity. At the molecular level, TIPARP selectively ADP-ribosylates AHR, but not AHR nuclear translocator (ARNT) and the Tiparp-dependent repression of AHR is reversed by the ADP-ribosylase and macrodomain containing protein MacroD1, but not MacroD2. These results describe previously unidentified roles for Tiparp, MacroD1, and ADP-ribosylation in AHR signaling, dioxin toxicity and lethality.
Project description:The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that mediates the toxic effects of the environmental contaminant, dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD). Dioxin causes a diverse range of toxic responses, including hepatic damage and lethal wasting syndrome; however, the mechanisms of dioxin-induced toxicity are still unknown. Here we show that the loss of TCDD-inducible poly(ADP-ribose) polymerase (TIPARP; ARTD14), an ADP-ribosyltransferase and AHR repressor, increases sensitivity to dioxin-induced toxicity and lethality. Tiparp-/- mice treated with a single injection of 100 mg/kg dioxin display an accelerated lethal wasting syndrome with no Tiparp-/- mice surviving beyond day 5; all Tiparp+/+ mice survived up to 30 days post treatment. Tiparp-/- mice displayed dramatic increases in liver steatosis and hepatotoxicity. At the molecular level, TIPARP selectively ADP-ribosylates AHR, but not AHR nuclear translocator (ARNT) and the Tiparp-dependent repression of AHR is reversed by the ADP-ribosylase and macrodomain containing protein MacroD1, but not MacroD2. These results describe previously unidentified roles for Tiparp, MacroD1, and ADP-ribosylation in AHR signaling, dioxin toxicity and lethality. 12 samples were analyzed. There were 4 treatment groups and each treatment group was done in triplicate. Gene expression changes were determine in hepatic RNA isolated from (1) corn oil treated C57BL/6;129Sv mice; (2) 30 ug/kg/bw 2,3,7,8-Tetrachlorodibenzo-p-dioxin C57BL/6;129Sv mice; (3) corn oil treated C57BL/6;129Sv Tiparp-/- mice; and (4) 30 ug/kg/bw 2,3,7,8-Tetrachlorodibenzo-p-dioxin C57BL/6;129Sv Tiparp-/- mice
Project description:The autosomal recessive immunodeficiency, centromeric instability and facial anomalies (ICF) syndrome is a genetically heterogeneous disorder. Despite recent successes in the identification of the underlying gene defects, it is currently unclear how mutations in any of the four known ICF genes cause a primary immunodeficiency. Here we demonstrate that loss of ZBTB24 in B cells from ICF2 patients impairs non-homologous end-joining (NHEJ) during immunoglobulin class-switch recombination and consequently impairs immunoglobulin production and subtype balance. Mechanistically, we found that ZBTB24 associates with poly(ADP-ribose) polymerase 1 (PARP1) and stimulates auto-poly(ADP-ribosyl)ation of this enzyme. The zinc finger in ZBTB24 binds PARP1-associated poly(ADP-ribose) chains and mediates the PARP1-dependent recruitment of ZBTB24 to DNA breaks. Moreover, by binding to poly(ADP-ribose) chains ZBTB24 protects these moieties from degradation by poly(ADP-ribose) glycohydrolase (PARG). This enhances the poly(ADP-ribose)-dependent interaction between PARP1 and the LIG4/XRCC4 NHEJ complex and promotes NHEJ by facilitating the assembly of this repair complex at DNA breaks. Thus, we uncover ZBTB24 as a regulator of PARP1-dependent NHEJ and class-switch recombination, providing a molecular basis for the immunodeficiency in ICF syndrome.
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 skeletal muscle.
Project description:Cockayne syndrome (CS) is an accelerated aging disorder, caused by mutations in the CSA or CSB genes. In CSB-deficient cells, poly (ADP ribose) polymerase (PARP) is persistently activated by unrepaired DNA damage and PARP consumes and depletes cellular nicotinamide adenine dinucleotide (NAD), which leads to mitochondrial dysfunction. Here, the distribution of poly (ADP ribose) (PAR) was determined in CSB-deficient cells using ADPr-ChAP (ADP ribose-chromatin affinity purification), and the results show striking enrichment of PAR at transcription start sites (TSS), depletion of heterochromatin, and downregulation of H3K9me3-specific methyltransferases SUV39H1 and SETDB1. Induced-expression of SETDB1 in CSB-deficient cells downregulated PAR and normalized mitochondrial function. The results suggest that defects in CSB are strongly associated with loss of heterochromatin, downregulation of SETDB1, increased PAR in highly-transcribed regions, and mitochondrial dysfunction.
Project description:Inhibitors of nuclear poly(ADP-ribose) polymerase (PARP) enzymes (e.g., PARP-1) have improved clinical outcomes in ovarian cancer, especially in patients with BRCA1/2 gene mutations or additional homologous recombination (HR) DNA repair pathway deficiencies. These defects serve as biomarkers for response to PARP inhibitors (PARPi). We sought to identify an additional biomarker that could predict responses to both conventional chemotherapy and PARPi in ovarian cancers. We focused on cellular ADP-ribosylation (ADPRylation), which is catalyzed by PARP enzymes and detected by detection reagents we developed previously. We determined molecular phenotypes of 34 high-grade serous ovarian cancers and associated them with clinical outcomes.
Project description:Here, we examined the interactions between PRMT6, poly(ADP-ribose) polymerase 1 (PARP1), and the cullin 4 B (CUL4B)-Ring E3 ligase (CRL4B) complex, to form a transcription-repressive complex that co-occupies the core clock gene PER3 promoter.
Project description:Analysis of HEK293T cells overexpressing ZAPS (zinc finger antiviral protein, short form; NP_078901), which is a member of the PARP (poly (ADP-ribose) polymerase)-superfamily. Results of gene profiles provide insight into the role of ZAPS in innate immunity.