Poly ADP-ribose Polymerase Gene Research Articles

Reduced Expression of DNA Damage Repair Genes High Mobility Group Box1 and Poly(ADP-ribose) Polymerase1 in Inactive Carriers of Hepatitis B Virus Infection-A Possible Stage of Viral Integration

High mobility group box1 (HMGB1) and poly(ADP-ribose) polymerase1 (PARP1) proteins repair cellular DNA damage. Reduced expression of the corresponding genes can lead to an impaired DNA damage repair mechanism. Intracellular replication of hepatitis B virus (HBV) in such conditions can favor the integration of viral DNA into host genome leading to the development of hepatocellular carcinoma (HCC). This study was performed to assess the expression of HMGB1 and PARP1 mRNAs in conjunction with the estimation of HBV replication intermediate pregenomic RNA (PgRNA) in various phases of HBV infection. Eighty eight patients and 26 voluntary blood donors as controls were included in the study. Patients were grouped in to acute (AHB; n=15), inactive carriers (IC; n=36), cirrhosis (Cirr; n=25) and hepatocellular carcinoma (HCC; n=12). Serum HBV DNA was quantified by real time polymerase chain reaction (PCR) assay. Expression of HMGB1, PARP1 and PgRNA were evaluated using peripheral blood mononuclear cells (PBMCs) derived RNA by reverse transcription PCR (RT-PCR) and densitometry. Significant reduction of HMGB1 and PARP1 gene expressions (P<0.05) were observed in patients than controls with more explicit decline of PARP1 (P=0.0002). Both genes were significantly downregulated (P<0.001) in ICs than controls. In ICs, HMGB1 was significantly lowered than cirrhosis (P=0.002) and HCC (P=0.0006) while PARP1 declined significantly (P=0.04) than HCC. Level of PgRNA was comparable in all the disease categories. In conclusion, our findings indicate impaired DNA damage repair mechanisms in HBV infected cells of ICs. This, along with low viral load but higher level of PgRNA in this group is suggestive of the diversion of HBV replication pathway that might facilitate viral DNA integration in to host genome. Intrusion of HBV PgRNA reverse transcription in early stage of infection might appear advantageous to thwart the development of HCC.

Poly (ADP-ribose) polymerase 1 protein expression in normal and neoplastic prostatic tissue

A genetic background has been implicated in the development of prostate cancer. Protein microarrays have enabled the identification of proteins, some of which associated with apoptosis, that may play a role in the development of such a tumor. Inhibition of apoptosis is a co-factor that contributes to the onset and progression of prostate cancer, though the molecular mechanisms are not entirely understood. Poly (ADP-ribose) polymerase 1 (PARP-1) gene is required for translocation of the apoptosis-inducing factor (AIF) from the mitochondria to the nucleus. Hence, it is involved in programmed cell death. Different PARP-1 gene expression has been observed in various tumors such as glioblastoma, lung, ovarian, endometrial, and skin cancers. We evaluated the expression of PARP-1 protein in prostatic cancer and normal prostate tissues by immunohistochemistry in 40 men with prostate cancer and in 37 normal men. Positive nuclear PARP-1 staining was found in all samples (normal prostate and prostate cancer tissues). No cytoplasmic staining was observed in any sample. PARP-1-positive cells resulted significantly higher in patients with prostate carcinoma compared with controls (P<0.001). PARP-1 over-expression in prostate cancer tissue compared with normal prostate suggests a greater activity of PARP-1 in these tumors. These findings suggest that PARP-1 expression in prostate cancer is an attempt to trigger apoptosis in this type of tumor similarly to what reported in other cancers.

Association of poly(ADP-ribose) polymerase-1 polymorphism with Tourette syndrome

Tourette syndrome (TS) is an etiologically heterogeneous disorder, the pathogenesis of which is incompletely understood. Poly(ADP-ribose) polymerase 1 (PARP1) is involved in regulation of developmental processes and cellular differentiation, in transcription regulation, in DNA repair, and in cell death. However, the relationship between TS and single nucleotide polymorphisms (SNPs) of PARP1 is unknown. Therefore, the aim of this experiment was to test the hypothesis that whether the PARP1 SNP, rs1805404 (c.243C>T, Asp81Asp), had an association with TS. A case-control experiment was designed to test this hypothesis. 123 TS children and 122 normal children were enrolled in this study. Polymerase chain reaction restriction fragment length polymorphism was used for the detection of the PARP1 SNP, rs1805404, in TS patients and normal children. The data showed that there is a significant difference in genotype distributions between these two groups. The CT genotype was a risk factor for TS with an odds ratio of 2.34 for the CT versus TT genotype (95% CI 1.16-4.74). The data also showed this SNP had an association with TS under recessive model (P = 0.0426), and TT genotype had a protective effect against TS with an odds ratio of 0.50 (95% CI 0.26-0.98). The findings of this study suggested that variants in the PARP1 gene might play a role in susceptibility to TS.

PARP1 gene expression is downregulated by knockdown of PARG gene

Poly(ADP-ribosyl)ation is a modification of nuclear proteins that regulates DNA replication, repair and transcription. In order to investigate the biological effects of degradation of poly(ADP-ribose), knockdown of the poly(ADP-ribose) glycohydrolase (PARG) gene was performed by introducing a short interfering RNA (siRNA)-pool into HeLa S3 cells. Notably, poly(ADP-ribosyl)ated proteins did not accumulate in the cells. Western blotting, quantitative RT-PCR analysis and a transient transfection assay revealed that poly(ADP-ribose) polymerase 1 (PARP1) gene/protein expression and its promoter activity were reduced in the PARG knockdown cells. These results suggest that the amount of poly(ADP-ribose) in a cell is regulated under the control of PARP1/PARG gene expression balance. Furthermore, in this study, we showed that PARG-siRNA enhanced cell death induced by staurosporine (STS). Thus, we propose a PARG-siRNA utilizing gene-therapy for cancer treatment.

PARP1 gene variation and microglial activity on [11C]PBR28 PET in older adults at risk for Alzheimer's disease.

Increasing evidence suggests that inflammation is one pathophysio-logical mechanism in Alzheimer's disease (AD). Recent studies have identifiedan association between the poly (ADP-ribose) polymerase 1 (PARP1) gene and AD. This gene encodes a protein that is involved in many biological functions, including DNA repair and chromatin remodeling, and is a mediator of inflammation. Therefore, we performed a targeted genetic association analysis to investigate the relationship between the PARP1 polymorphisms and brain micro-glial activity as indexed by [11C]PBR28 positron emission tomography (PET). Participants were 26 non-Hispanic Caucasians in the Indiana Memory and Aging Study (IMAS). PET data were intensity-normalized by injected dose/total body weight. Average PBR standardized uptake values (SUV) from 6 bilateral regions of interest (thalamus, frontal, parietal, temporal, and cingulate cortices, and whole brain gray matter) were used as endophenotypes. Single nucleotide polymorphisms (SNPs) with 20% minor allele frequency that were within +/- 20 kb of the PARP1 gene were included in the analyses. Gene-level association analyses were performed using a dominant genetic model with translocator protein (18-kDa) (TSPO) genotype, age at PET scan, and gender as covariates. Analyses were performed with and without APOE ε4 status as a covariate. Associations with PBR SUVs from thalamus and cingulate were significant at corrected p<0.014 and <0.065, respectively. Subsequent multi-marker analysis with cingulate PBR SUV showed that individuals with the "C" allele at rs6677172 and "A" allele at rs61835377 had higher PBR SUV than individuals without these alleles (corrected P<0.03), and individuals with the "G" allele at rs6677172 and "G" allele at rs61835377 displayed the opposite trend (corrected P<0.065). A previous study with the same cohort showed an inverse relationship between PBR SUV and brain atrophy at a follow-up visit, suggesting possible protective effect of microglial activity against cortical atrophy. Interestingly, all 6 AD and 2 of 3 LMCI participants in the current analysis had one or more copies of the "GG" allele combination, associated with lower cingulate PBR SUV, suggesting that this gene variant warrants further investigation.

Erythropoietin-driven signalling and cell migration mediated by polyADP-ribosylation

Background:Recombinant human erythropoietin (EPO) is the leading biotechnology engineered hormone for treatment of anaemia associated with chronic conditions including kidney failure and cancer. The finding of EPO receptors on cancer cells has raised the concern that in addition to its action in erythropoiesis, EPO may promote tumour cell growth. We questioned whether EPO-induced signalling and consequent malignant cell manifestation is mediated by polyADP-ribosylation.Methods:Erythropoietin-mediated PARP (polyADP-ribose polymerase-1) activation, gene expression and core histone H4 acetylation were examined in UT7 cells, using western blot analysis, RT–PCR and immunofluorescence. Erythropoietin-driven migration of the human breast epithelial cell line MDA-MB-435 was determined by the scratch assay and in migration chambers.Results:We have found that EPO treatment induced PARP activation. Moreover, EPO-driven c-fos and Egr-1 gene expression as well as histone H4 acetylation were mediated via polyADP-ribosylation. Erythropoietin-induced cell migration was blocked by the PARP inhibitor, ABT-888, indicating an essential role for polyADP-ribosylation in this process.Conclusions:We have identified a novel pathway by which EPO-induced gene expression and breast cancer cell migration are regulated by polyADP-ribosylation. This study introduces new possibilities regarding EPO treatment for cancer-associated anaemia where combining systemic EPO treatment with targeted administration of PARP inhibitors to the tumour may allow safe treatment with EPO, minimising its possible undesirable proliferative effects on the tumour.

YY1-binding sites provide central switch functions in the PARP-1 gene expression network.

Evidence is presented for the involvement of the interplay between transcription factor Yin Yang 1 (YY1) and poly(ADP-ribose) polymerase-1 (PARP-1) in the regulation of mouse PARP-1 gene (muPARP-1) promoter activity. We identified potential YY1 binding motifs (BM) at seven positions in the muPARP-1 core-promoter (−574/+200). Binding of YY1 was observed by the electrophoretic supershift assay using anti-YY1 antibody and linearized or supercoiled forms of plasmids bearing the core promoter, as well as with 30 bp oligonucleotide probes containing the individual YY1 binding motifs and four muPARP-1 promoter fragments. We detected YY1 binding to BM1 (−587/−558), BM4 (−348/−319) and a very prominent association with BM7 (+86/+115). Inspection of BM7 reveals overlap of the muPARP-1 translation start site with the Kozak sequence and YY1 and PARP-1 recognition sites. Site-directed mutagenesis of the YY1 and PARP-1 core motifs eliminated protein binding and showed that YY1 mediates PARP-1 binding next to the Kozak sequence. Transfection experiments with a reporter gene under the control of the muPARP-1 promoter revealed that YY1 binding to BM1 and BM4 independently repressed the promoter. Mutations at these sites prevented YY1 binding, allowing for increased reporter gene activity. In PARP-1 knockout cells subjected to PARP-1 overexpression, effects similar to YY1 became apparent; over expression of YY1 and PARP-1 revealed their synergistic action. Together with our previous findings these results expand the PARP-1 autoregulatory loop principle by YY1 actions, implying rigid limitation of muPARP-1 expression. The joint actions of PARP-1 and YY1 emerge as important contributions to cell homeostasis.

Poly(ADP-ribose) Polymerase-1 in Amyloid Beta Toxicity and Alzheimer's Disease

Poly(ADP-ribose) polymerase-1 (PARP-1) is a key enzyme responsible for the maintenance of genome stability, transcriptional regulation, and long-term potentiation in neurons. However, the excessive activation of PARP-1 under pathological conditions may lead to an accumulation of poly(ADP-ribose) (PAR), a novel signaling molecule that induces programmed cell death, or to NAD depletion that induces energy crisis and necrotic cell death. PARP-1 is thought to be primarily a nuclear enzyme, but some data indicate that it can also be localized to the mitochondria where it is responsible for posttranslational modification of electron transport chain complexes and alteration of mitochondria function. The enhancement of PARP-1 activity and the accumulation of PAR were demonstrated in the brain of patients with Alzheimer's disease (AD), particularly in neurons of the frontal and temporal lobes and in skin fibroblasts and lymphoblasts. Moreover, it has been reported that PARP-1 gene polymorphisms are highly associated with the development of AD. The activation of PARP-1 by oxidative stress seems to be an early and important event in the pathogenesis of AD. It is now widely accepted that the overproduction and oligomerization of amyloid β (Aβ) are responsible for the activation of a free radical cascade and oxidative stress in AD. Interestingly, the activity of PARP-1 is enhanced in AD and is also increased by Aβ peptides. The activation of PARP-1 by Aβ can lead to the PAR-mediated release of apoptosis-inducing factor from the mitochondria and its translocation to the nucleus, which leads to death of some populations of cells. A role of PARP-1 in the regulation of Aβ precursor protein metabolism processing and Aβ liberation has not been described previously. The study presented in this review indicated the relationship between PARP-1 activation, alteration of mitochondria function, and Aβ toxicity. The presented data should stimulate further studies on the role of PARP-1 in AD pathogenesis and thereby engage a new perspective regarding AD therapy.

PARP-1 protein expression in glioblastoma multiforme

One of the most common type of primary brain tumors in adults is the glioblastoma multiforme (GBM) (World Health Organization grade IV astrocytoma). It is the most common malignant and aggressive form of glioma and it is among the most lethal ones. Poly (ADP-ribose) polymerase 1 (PARP-1) gene, located to 1q42, plays an important role for the efficient maintenance of genome integrity. PARP-1 protein is required for the apoptosis-inducing factor (AIF) translocation from the mitochondria to the nucleus. PARP-1 is proteolytically cleaved at the onset of apoptosis by caspase-3. Microarray analysis of PARP-1 gene expression in more than 8000 samples revealed that PARP-1 is more highly expressed in several types of cancer compared with the equivalent normal tissues. Overall, the most differences in PARP-1 gene expression have been observed in breast, ovarian, endometrial, lung, and skin cancers, and non-Hodgkin's lymphoma. We evaluated the expression of PARP-1 protein in normal brain tissues and primary GBM by immunohistochemistry. Positive nuclear PARP-1 staining was found in all samples with GBM, but not in normal neurons from controls (n=4) and GBM patients (n=27). No cytoplasmic staining was observed in any sample. In conclusion, PARP-1 gene is expressed in GBM. This finding may be envisioned as an attempt to trigger apoptosis in this tumor, as well as in many other malignancies. The presence of the protein exclusively at the nucleus further support the function played by this gene in genome integrity maintenance and apoptosis. Finally, PARP-1 staining may be used as GBM cell marker.

Abstract C109: Association of TP53 gene polymorphism with response to platinum-based doublet chemotherapy in non-small cell lung cancer patients.

Abstract Here we show that TP53 SNP is involved in chemotherapeutic responses in non-small cell lung cancer (NSCLC) patients. To identify polymorphisms in DNA repair genes that affect responses to platinum-based doublet chemotherapy, 640 NSCLC patients, who received platinum-based doublet chemotherapy and whose responses were evaluated by the Response Evaluation Criteria in Solid Tumors, were subjected to an association study between the response and genotypes for 30 SNPs in 27 DNA repair genes. Candidate SNPs were selected by screening of a discovery set of 201 cases and their associations were validated in an independent set of 439. Homozygotes for the TP53–72Pro allele of the TP53-Arg72Pro SNPs showed a better response rate (54.3%) than those for the TP53–72Arg allele (29.1%), and TP53–72Pro allele homozygotes had significantly longer progression-free and overall survivals than TP53–72Arg allele homozygotes. Minor allele carriers for a SNP, Lys940Arg, in the PARP1 (poly ADP-ribose polymerase 1) gene showed a better response rate to the regimen using paclitaxel (45.8%) than to the regimen using gemcitabine (10.5%). These results indicate that polymorphisms in the TP53 and PARP1 genes are involved in inter-individual differences in the response to platinum-based doublet chemotherapy in NSCLC patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C109.

Association analysis of PARP1 polymorphisms with Parkinson’s disease

Alpha-synuclein accumulation in intracellular inclusions, oxidative stress and microglia-mediated inflammation in the substantia nigra are crucial events in the pathogenesis of Parkinson’s disease (PD). Poly (ADP-ribose) polymerase-1 (PARP1), a DNA-binding enzyme and transcriptional regulator, plays an important role in modulating the cellular response to oxidative stress, inflammatory stimuli, and in apoptotic cell death. Inhibition of PARP1 results in significant neuroprotection in PD animal models; moreover PARP1 has a physiological role in the regulation of alpha-synuclein expression. A previous study had demonstrated that variants located within the PARP1 gene promoter reduce the risk of PD and delay the disease age at onset. In light of these data, we carried out an association study to investigate whether variability within this gene is associated with PD risk and disease age at onset in an Italian cohort composed of 600 PD patients and 592 healthy controls. To this purpose, we used a comprehensive tag SNP approach spanning the entire gene and the upstream and downstream regions. We did not detect any significant association of the PARP1 gene with PD either at genotypic or haplotypic level; none of the 11 genotyped SNPs was significantly associated with PD age at onset. We conclude that, despite previous evidence, PARP1 is not a susceptibility gene for PD in our population.

PARP1 and CASP3 gene expression in a patient with multiple head and neck squamous cell carcinoma and Parkinson disease

This letter describes an interesting case of a 98-year-old woman with multiple head and neck squamous cell carcinoma (HNSCC) and Parkinson disease (PD). The following squamous cell cancers were discovered in this patient: (1) squamous cell carcinoma of the tongue, diagnosed and excised in 2004 with complete clinical recovery; and (2) in situ squamous cell carcinoma of the right cheek and the neck, diagnosed in 2009. She also presented difficulty in the dexterity of the right hand and a typical PD asymmetric presentation. Indeed, the patient had a rest tremor and cogwheel rigidity, bradykinesia bilaterally, stooped posture, turns en bloc, and decreased armswing on the right. These symptoms were responsive to the administration of L-DOPA. It is well known that head and neck cancer is one of the most common worldwide and that tobacco and alcohol consumptions are primary risk factors for HNSCC [1]. On the other hand, PD is one of the most common neurodegenerative disorder with a prevalence of 3% in persons over the age of 65 years [1]. PD is characterized by the presence of intracytoplasmic inclusions, named Lewy bodies (LB), and by a massive loss of dopaminergic neurons in the substantia nigra [2]. Most PD cases are sporadic, but about 15% of them are associated with genetic causes. The loss of dopaminergic afferents from the substantia nigra to the striatum and putamen results in extrapyramidal motor dysfunction, including tremor, rigidity, and bradykinesia. Another hallmark of PD is gliosis, an accumulation of activated microglia and astrocytes in the substantia nigra and striatum [2], although it remains to be clarified how gliosis is initiated and sustained in PD. The symptoms of PD can be ameliorated by medications, such as precursors of dopamines, but these remedies cannot prevent or retard the neurodegenerative progression [3]. Apoptosis is a programmed cell death process under both normal physiological and pathological conditions. Caspases, a family of cysteine-dependent aspartate-specific proteases, are important mediators of the apoptotic process [3]. Caspases cleave numerous intracellular substrates in the initiation of cell dissolution [3, 4]. Caspase 3, apoptosis-related cysteine peptidase (CASP3), maps to human chromosome 4q35 and plays important roles in the extrinsic and intrinsic apoptosis pathways (MIM 600636). Recent molecular epidemiological studies suggest that CASP3 may contribute to HNSCC susceptibility and disease progression and that increased CASP3 expression is associated with tumors of the mouth [5]. Moreover, previous studies suggested that CASP3 activation and subsequent apoptosis of dopamine neurons in the substantia nigra may be the initial step essential for the development of PD [6]. The poly (ADP-ribose) polymerase 1 (PARP1) gene, located at 1q42, is 43 Kb long and splits into 23 exons A. E. Calogero M. C. Giuffrida D. Giuffrida S. La Vignera R. Castiglione M. Salemi Section of Endocrinology, Andrology and Internal Medicine, Department of Internal Medicine and Systemic Diseases, University of Catania, Catania, Italy

Poly(ADP-ribose) polymerase-1 (PARP-1) pharmacogenetics, activity and expression analysis in cancer patients and healthy volunteers

There is a wide inter-individual variation in PARP-1 {PAR [poly(ADP-ribose)] polymerase 1} activity, which may have implications for health. We investigated if the variation: (i) is due to polymorphisms in the PARP-1 gene or PARP-1 protein expression; and (ii) affects patients' response to anticancer treatment. We studied 56 HV (healthy volunteers) and 118 CP (cancer patients) with supporting in vivo experiments. PARP activity ranged between 10 and 2600 pmol of PAR/106 cells and expression between 0.02-1.55 ng of PARP-1/μg of protein. PARP-1 expression correlated with activity in HV (R2=0.19, P=0.003) and CP (R2=0.06, P=0.01). A short CA repeat in the promoter was significantly associated with increased cancer risk [OR (odds ratio), 5.22; 95% CI (confidence interval), 1.79-15.24]. PARP activity was higher in men than women (P=0.04) in the HV. Male mice also had higher PARP activity than females or castrated males. Oestrogen supplementation activated PARP in PBMCs (peripheral blood mononuclear cells) from female mice (P=0.003), but inhibited PARP-1 in their livers by 80%. PARP activity and expression were not dependent on the investigated polymorphisms, but there was a modest correlation of PARP activity with expression. Studies in the HV revealed sex differences in PARP activity, which was confirmed in mice and shown to be associated with sex hormones. Toxic response to treatment was not associated with PARP activity and/or expression.

Neuroprotective potential of erythropoietin and its derivative carbamylated erythropoietin in periventricular leukomalacia

Periventricular leukomalacia (PVL) is the predominant pathology in premature infants, characterized by prominent cerebral white matter injury, and commonly caused by hypoxia–ischemia and inflammation. Activated microglia trigger white matter damage and play a major role in the development of PVL. Erythropoietin (EPO) and its derivative carbamylated erythropoietin (CEPO) have been shown to be neuroprotective in several brain disease models. Here we investigated whether EPO and CEPO could provide protection in mouse models of PVL induced by hypoxia–ischemia or hypoxia–ischemia-inflammation. We administered EPO or CEPO to mice with PVL, and found that both EPO and CEPO treatments decreased microglia activation, oligodendrocyte damage and myelin depletion. We also noted improved performance in neurological function assays. Inhibited disease progression in PVL mice by EPO or CEPO treatment was associated with decreased poly-(ADP-ribose) polymerase-1 (PARP-1) activity. PARP-1 activity was increased dramatically in activated microglia in untreated mice with PVL. Furthermore, we demonstrated that the neuroprotective properties of EPO and CEPO were diminished after PARP-1 gene depletion. The therapeutic doses of EPO and CEPO used in this study did not interfere with normal oligodendrocyte maturation and myelination. Together, our data demonstrate that EPO and CEPO are neuroprotective in cerebral white matter injury via a novel microglial PARP-1 dependent mechanism, and hold promise as a future treatment for PVL and other hypoxic–ischemic/inflammatory white matter diseases.

RANKL Up-regulates Brain-type Creatine Kinase via Poly(ADP-ribose) Polymerase-1 during Osteoclastogenesis

Receptor activator of nuclear factor κB ligand (RANKL) is the key regulator for osteoclast formation and function. During osteoclastogenesis, RANKL-stimulated signals differentially modulate expression of a large number of proteins. Using proteomics approaches, we identified that brain-type cytoplasmic creatine kinase (Ckb) was greatly induced in mature osteoclasts. Ckb has been shown to contribute to osteoclast function. However, the mechanisms of Ckb regulation and the contribution of other isoforms of creatine kinase during RANKL-induced osteoclastogenesis are unknown. We found that Ckb was the predominant isoform of creatine kinase during osteoclastogenesis. Real-time PCR confirmed that RANKL induced ckb mRNA expression by over 40-fold in primary mouse bone marrow macrophages and Raw 264.7 cells. The RANKL-responsive region was identified within the -0.4- to -0.2-kb 5'-flanking region of the ckb gene. Affinity binding purification followed by mass spectrometry analysis revealed that poly(ADP-ribose) polymerase-1 (PARP-1) bound to the -0.4/-0.2-kb fragment that negatively regulated expression of ckb in response to RANKL stimulation. Electrophoretic mobility shift assays with PARP-1-specific antibody located the binding site of PARP-1 to the TTCCCA consensus sequence. The expression of PARP-1 was reduced during RANKL-induced osteoclastogenesis, concurrently with increased expression of Ckb. Consistently, knockdown of PARP-1 by lentivirus-delivered shRNA enhanced ckb mRNA expression. The activity of PARP-1 was determined to be required for its inhibitory effect on the ckb expression. In summary, we have demonstrated that PARP-1 is a negative regulator of the ckb expression. Down-regulation of PARP-1 is responsible for the up-regulation of ckb during RANKL-induced osteoclastogenesis.

Evolutionary history of the poly(ADP-ribose) polymerase gene family in eukaryotes.

BackgroundThe Poly(ADP-ribose)polymerase (PARP) superfamily was originally identified as enzymes that catalyze the attachment of ADP-ribose subunits to target proteins using NAD+ as a substrate. The family is characterized by the catalytic site, termed the PARP signature. While these proteins can be found in a range of eukaryotes, they have been best studied in mammals. In these organisms, PARPs have key functions in DNA repair, genome integrity and epigenetic regulation. More recently it has been found that proteins within the PARP superfamily have altered catalytic sites, and have mono(ADP-ribose) transferase (mART) activity or are enzymatically inactive. These findings suggest that the PARP signature has a broader range of functions that initially predicted. In this study, we investigate the evolutionary history of PARP genes across the eukaryotes.ResultsWe identified in silico 236 PARP proteins from 77 species across five of the six eukaryotic supergroups. We performed extensive phylogenetic analyses of the identified PARPs. They are found in all eukaryotic supergroups for which sequence is available, but some individual lineages within supergroups have independently lost these genes. The PARP superfamily can be subdivided into six clades. Two of these clades were likely found in the last common eukaryotic ancestor. In addition, we have identified PARPs in organisms in which they have not previously been described.ConclusionsThree main conclusions can be drawn from our study. First, the broad distribution and pattern of representation of PARP genes indicates that the ancestor of all extant eukaryotes encoded proteins of this type. Second, the ancestral PARP proteins had different functions and activities. One of these proteins was similar to human PARP1 and likely functioned in DNA damage response. The second of the ancestral PARPs had already evolved differences in its catalytic domain that suggest that these proteins may not have possessed poly(ADP-ribosyl)ation activity. Third, the diversity of the PARP superfamily is larger than previously documented, suggesting as more eukaryotic genomes become available, this gene family will grow in both number and type.

Association of DNA Repair Gene Polymorphisms With Response to Platinum-Based Doublet Chemotherapy in Patients With Non–Small-Cell Lung Cancer

To identify polymorphisms in DNA repair genes that affect responses to platinum-based doublet chemotherapy in patients with non-small-cell lung cancer (NSCLC). In total, 640 patients with NSCLC who received platinum-based doublet chemotherapy in the National Cancer Center Hospital in Japan from 2000 to 2008 and whose responses were evaluated by Response Evaluation Criteria in Solid Tumors (RECIST) participated in a study of the association between response and genotypes for 30 single nucleotide polymorphisms (SNPs) in 27 DNA repair genes. Candidate SNPs were selected in a discovery set of 201 patients, and their associations were validated in an independent set of 439 patients by prespecified P value criteria. Homozygotes for the minor allele TP53-72Pro of the Arg72Pro SNP in the TP53 gene showed a better response rate (54.3%) than those for the major allele TP53-72Arg (29.1%; P = 4.4 × 10(-5)) irrespective of therapeutic regimens, and minor allele homozygotes had significantly longer progression-free and overall survivals than major allele homozygotes (hazard ratio [HR], 0.85; 95% CI, 0.74 to 0.98; P = .020; and HR, 0.86; 95% CI, 0.74 to 0.99; P = .039). Minor allele carriers for SNP Lys940Arg in the poly (ADP-ribose) polymerase 1 (PARP1) gene showed a better response rate to the paclitaxel regimen (45.8%) than to the gemcitabine regimen (10.5%; P for interaction = .019). Polymorphisms in the TP53 and PARP1 genes are involved in inter-individual differences in the response to platinum-based doublet chemotherapy in patients with NSCLC.

Upregulation of Poly (ADP-Ribose) Polymerase-1 (PARP1) in Triple-Negative Breast Cancer and Other Primary Human Tumor Types

Poly (ADP-ribose) polymerase-1 (PARP1) is a key facilitator of DNA repair and is implicated in pathways of tumorigenesis. PARP inhibitors have gained recent attention as rationally designed therapeutics for the treatment of several malignancies, particularly those associated with dysfunctional DNA repair pathways, including triple-negative breast cancer (TNBC). We investigated the PARP1 gene expression profile in surgical samples from more than 8,000 primary malignant and normal human tissues. PARP1 expression was found to be significantly increased in several malignant tissues, including those isolated from patients with breast, uterine, lung, ovarian, and skin cancers, and non-Hodgkin's lymphoma. Within breast infiltrating ductal carcinoma (IDC) samples tested, mean PARP1 expression was significantly higher relative to normal breast tissue, with over 30% of IDC samples demonstrating upregulation of PARP1, compared with 2.9% of normal tissues. Because of known DNA repair defects, including BRCA1 dysfunction, associated with TNBC, exploration of PARP1 expression in breast cancers related to expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) led to the observation that negative expression of any of the 3 receptors was associated with upregulation of PARP1 expression, compared with receptor-positive tissues. To validate these observations, an independent set of breast adenocarcinomas was evaluated and demonstrated >2-fold upregulation of PARP1 in approximately 70% of primary breast adenocarcinomas, including TNBC, compared with syngeneic nonmalignant breast tissues. Immunohistochemistry (IHC) showed that upregulation of the PARP1 gene was consistent with increased protein expression in TNBC. These analyses suggest a potential biological role for PARP1 in several distinct malignancies, including TNBC. Further investigation of PARP1 as a biomarker for the therapeutic activity of PARP inhibitor-based therapy is warranted.

Poly(ADP-ribose) polymerase-1 (PARP-1) gene deficiency alleviates diabetic kidney disease

Poly(ADP-ribose)polymerase (PARP) inhibitors prevent or alleviate diabetic nephropathy. This study evaluated the role for PARP-1 in diabetic kidney disease using the PARP-1-deficient mouse. PARP-1−/− and the wild-type (129S1/SvImJ) mice were made diabetic with streptozotocin, and were maintained for 12 weeks. Final blood glucose concentrations were increased ∼ 3.7-fold in both diabetic groups. PARP-1 protein expression (Western blot analysis) in the renal cortex was similar in non-diabetic and diabetic wild-type mice (100% and 107%) whereas all knockouts were PARP-1-negative. PARP-1 gene deficiency reduced urinary albumin (ELISA) and protein excretion prevented diabetes-induced kidney hypertrophy, and decreased mesangial expansion and collagen deposition (both assessed by histochemistry) as well as fibronectin expression. Renal podocyte loss (immunohistochemistry) and nitrotyrosine and transforming growth factor-β 1 accumulations (both by ELISA) were slightly lower in diabetic PARP-1−/− mice, but the differences with diabetic wild-type group did not achieve statistical significance. In conclusion, PARP-1−/− gene deficiency alleviates although does not completely prevent diabetic kidney disease.

Abstract 4656: DNA repair polymorphisms as predictors of Graft-versus-Host Disease after allogeneic hematopoietic cell transplants

Abstract Graft versus host disease (GVHD) remains a major source of morbidity and mortality among patients undergoing hematopoietic cell transplants (HCT). Tissue damage as a result of treatment is the initiating event in the pathogenesis of GVHD and variations in DNA repair can influence the amount of tissue damage in response to treatment modalities used in HCT. Since DNA damage caused by therapeutic agents such as alkylating agents and ionizing radiation used frequently in pre- HCT conditioning regimens is commonly repaired by the base excision repair (BER) pathway we hypothesized that genetic polymorphisms in the BER pathway will be associated with GVHD after HCT. We evaluated the association between single nucleotide polymorphisms (SNPs) (n= 179) in the BER pathway with acute GVHD and chronic GVHD in a cohort of 470 recipients who underwent allogeneic HCT for treatment of hematologic malignancies at the University of Minnesota. After adjustment for donor type, diagnosis, disease status at transplant and gender mismatch, two SNPs in RFC1 (Replication Factor C) gene (rs1057807 and rs4975003) were associated with a decreased risk of grade II-IV acute GVHD (HR:0.74-0.77; p≤0.01) and one SNP, rs6844176, in RFC1 gene was associated with increased risk of grade II-IV acute GVHD (HR:1.39, p=0.001). The rs3730914 SNP in the LIG1 (Ligase I) gene was also associated with a decreased risk of grade III-IV acute GVHD (HR: 0.38; p=0.005). One SNP, rs1805410, in the PARP1 (poly ADP-ribose polymerase 1) gene was associated with increased risk of chronic GVHD (HR: 1.44; p=0.01) post HCT. These findings suggest that SNPs in the BER pathway can be used as genetic biomarkers to predict individuals at high risk for GVHD. If these findings are confirmed, modulation of pre-transplant conditioning may alter risk in these patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4656.