Overexpression Of Poly ADP-ribose Polymerase Research Articles

Quinazoline-2,4(1H,3H)-dione Scaffold for development of a novel PARP-targeting PET probe for tumor imaging.

Overexpression of Poly (ADP-ribose) polymerase (PARP) is associated with many diseases such as oncological diseases. Several PARP-targeting radiotracers have been developed to detect tumor in recent years. Two 18F labelled probes based on Olaparib and Rucaparib molecular scaffolds have been evaluated in clinical trials, but their slow hepatic clearance hinders their tumor imaging performance. Although a number of positron emission tomography (PET) probes with lower liver uptake have been designed, the tumor to background ratios remains to be low. Therefore, we designed a probe with low lipid-water partition coefficient to solve this problem. A pyridine-containing quinazoline-2,4(1H,3H)-dione PARP-targeting group was rationally designed and used to conjugate with the chelator 2,2',2'',2'''-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA) to prepare the lead compound named as SMIC-2001 for radiolabeling. In vitro experiments, the lipid-water partition coefficient, stability, binding affinity, and cellular uptake of [68Ga]Ga-SMIC-2001 were determined. In vivo experiments, the U87MG xenograft models were used to evaluate its tumor imaging properties. [68Ga]Ga-SMIC-2001 showed a low Log D7.4 (-3.82 ± 0.06) and high affinity for PARP-1 (48.13 nM). In vivo study revealed that it exhibited a high tumor-to-background contrast in the U87MG xenograft models and mainly renal clearance. And the ratios of tumor to main organs were high except for the kidney (e.g. tumor to liver ratio reached 2.20 ± 0.51) at 60min p.i. In summary, pyridine-containing quinazoline-2,4(1H,3H)-dione is a novel PARP-targeting molecular scaffold for imaging probe development, and [68Ga]Ga-SMIC-2001 is a highly promising PET probe capable of imaging tumors with PARP overexpression.

Gemcitabine, carboplatin and veliparib in multiple relapsed/refractory germ cell tumours: The GCT-SK-004 phase II trial

BackgroundPatients with multiple relapsed/refractory germ cell tumours (GCTs) have an extremely poor prognosis. PARP (poly-ADP-ribose polymerase) is overexpressed in GCTs compared to normal testes, and PARP overexpression is an early event in GCT development. This study aimed to determine the efficacy and toxicity of gemcitabine, carboplatin and the PARP inhibitor veliparib in patients with multiple relapsed/refractory GCTs. MethodsFifteen patients with multiple relapsed/refractory GCTs were enrolled in this phase II study from October 2016 to October 2020. Gemcitabine was administered at a dose of 800mg/m2 on days 1 and 8 every 3 weeks; carboplatin at a target AUC of 4 on day 1 every 3 weeks; and veliparib at a dose of 250mg b.i.d. throughout. The primary end point was 12-month progression-free survival (PFS). ResultsThe median number of treatment cycles was 4 (range 2-8). Twelve-month PFS was achieved in 1 (6.7 %) patient. The median PFS was 3.1 months (95 % CI 2.2-3.9), and the median overall survival was 10.5 months (95 % CI 8.9-11.1). Partial remission was achieved in 4 (26.7 %) patients, and disease stabilization was observed in 5 (33.3 %) patients. A favourable response was achieved in 3 (20.0 %) patients. Treatment was well tolerated; however, 11 (73.3 %) patients experienced grade 3/4 neutropenia, 10 (66.7 %) experienced thrombocytopenia, 5 (33.3 %) anaemia and 2 (13.3 %) febrile neutropenia. ConclusionsThis study failed to achieve its primary endpoint, and our data suggest limited efficacy of gemcitabine, carboplatin and veliparib for multiple relapsed/refractory GCTs. ClinicalTrials.gov Identifier: NCT02860819, registered August 9, 2016.

Specific protein 1 inhibitor mithramycin A protects cardiomyocytes from myocardial infarction via interacting with PARP.

Specific protein 1 (SP1) might act as a critical transcription regulator in myocardial infarction (MI), but little evidence about its function in regulating cardiac apoptosis, a major cause of MI development, has been revealed. This study tried to investigate the role of SP1 in MI and its interaction with poly-ADP-ribose polymerase (PARP)-1 by using SP1 inhibitor, mithramycin A (mithA). Primary mouse cardiomyocytes and commercial mouse cardiomyocytes were subjected to mithA treatment under hypoxia conditions, while cell viability, Nix promoter activity, and its expression were detected correspondingly. PARP overexpression and knockdown were conducted, respectively, in mithA-treated and SP1-overexpressing cells. Co-immunoprecipitation was used to verify the interaction between PARP and SP1. For in vivo experiments, mithA administration was performed after the injections of adenovirus for PARP overexpression, and then, MI introduction was carried out. Infarct size and lactate dehydrogenase level were measured to assess MI injury. SP1 inhibitor mithA attenuated hypoxia-induced decrease of cell viability and Nix transcriptional activation, which could be inhibited by PARP overexpression. Knockdown of PARP prevented SP1-induced transcription of Nix and cell viability change, and PARP showed direct interaction with SP1. Furthermore, mithA administration reduced MI injuries, while PARP overexpression could suppress the improvement. The cardioprotective role of SP1 inhibitor mithA was demonstrated here expanding the role of SP1 in MI development involving hypoxia-induced cardiac apoptosis. Moreover, PARP acted as a transcriptional coactivator in Nix transcription involving its interaction with SP1.

Abstract 4300: Overexpression of PARP is an independent prognostic marker for poor survival in Middle Eastern breast cancer and its inhibition can be enhanced with embelin co-treatment

Abstract Patients with aggressive breast cancer (BC) subtypes usually don’t have favorable prognosis despite the improvement in treatment modalities. These cancers still remain a major cause of morbidity and mortality in females. This has fostered a major effort to discover actionable molecular targets to treat these patients. Poly ADP ribose polymerase (PARP) is one of these molecular targets that are under comprehensive investigation for treatment of such tumors. However, its role in the pathogenesis of BC from Middle Eastern ethnicity has not yet explored. Therefore, we examined the expression of PARP protein in a large cohort of over 1000 Middle Eastern BC cases by immunohistochemistry. Correlation with clinico-pathological parameters were performed. Nuclear PARP overexpression was observed in 44.7% of all BC cases and was significantly associated with aggressive clinico-pathological markers. Interestingly nuclear PARP overexpression was an independent predictor of poor prognosis. PARP overexpression was also directly associated with XIAP overexpression, with PARP and XIAP co-expression in 15.8% (159/1008) of our cases. We showed that combined inhibition of PARP by olaparib and XIAP by embelin significantly and synergistically inhibited cell growth and induced apoptosis in BC cell lines. Finally, co-treatment of olaparib and embelin regressed BC xenograft tumor growth in nude mice. Our results revealed the role of PARP in Middle Eastern BC pathogenesis and prognosis. Furthermore, our data support the potential clinical development of combined inhibition of PARP and XIAP, which eventually could extend the utility of olaparib beyond BRCA deficient cancer. Citation Format: Maqbool Ahmed, Abdul K. Siraj, Poyil Pratheeshkumar, Sandeep Parvathareddy, Sasidharan Padmaja Divya, Fouad Al-Dayel, Asma Tulbah, Dahish Ajarim, Khawla S. Al-Kuraya. Overexpression of PARP is an independent prognostic marker for poor survival in Middle Eastern breast cancer and its inhibition can be enhanced with embelin co-treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4300.

Overexpression of PARP is an independent prognostic marker for poor survival in Middle Eastern breast cancer and its inhibition can be enhanced with embelin co-treatment.

Patients with aggressive breast cancer (BC) subtypes usually don’t have favorable prognosis despite the improvement in treatment modalities. These cancers still remain a major cause of morbidity and mortality in females. This has fostered a major effort to discover actionable molecular targets to treat these patients. Poly ADP ribose polymerase (PARP) is one of these molecular targets that are under comprehensive investigation for treatment of such tumors. However, its role in the pathogenesis of BC from Middle Eastern ethnicity has not yet been explored. Therefore, we examined the expression of PARP protein in a large cohort of over 1000 Middle Eastern BC cases by immunohistochemistry. Correlation with clinico-pathological parameters were performed. Nuclear PARP overexpression was observed in 44.7% of all BC cases and was significantly associated with aggressive clinico-pathological markers. Interestingly, nuclear PARP overexpression was an independent predictor of poor prognosis. PARP overexpression was also directly associated with XIAP overexpression, with PARP and XIAP co-expression in 15.8% (159/1008) of our cases. We showed that combined inhibition of PARP by olaparib and XIAP by embelin significantly and synergistically inhibited cell growth and induced apoptosis in BC cell lines. Finally, co-treatment of olaparib and embelin regressed BC xenograft tumor growth in nude mice. Our results revealed the role of PARP in Middle Eastern BC pathogenesis and prognosis. Furthermore, our data support the potential clinical development of combined inhibition of PARP and XIAP, which eventually could extend the utility of olaparib beyond BRCA deficient cancer.

Lipoic acid alleviates L‑DOPA‑induced dyskinesia in 6‑OHDA parkinsonian rats via anti‑oxidative stress.

Levodopa (L‑DOPA) is the gold standard for symptomatic treatment of Parkinson's disease (PD); however, long‑term therapy is associated with the emergence of L‑DOPA‑induced dyskinesia (LID). Nigral dopaminergic cell loss determines the degree of drug exposure and time required for the initial onset of LID. Accumulating evidence indicates that α‑lipoic acid (ALA) decreases this nigral dopaminergic cell loss. However, until now, the precise mechanisms of ALA have only been partially understood in LID. Chronic L‑DOPA treatment was demonstrated to develop intense AIM scores to assess dyskinetic symptoms. Rats in the LID group were administrated twice daily with L‑DOPA+benserazide for 3weeks to induce a rat model of dyskinesia. Moreover, other 6‑OHDA‑lesioned rats were treatment with ALA (31.5mg/kg or 63mg/kg) in combination with L‑DOPA treatment. Furthermore, the authors investigated the level of malondialdehyde (MDA) and glutathione (GSH) activity, as well as IBa‑1, caspase‑3 and poly (ADP-ribose) polymerase (PARP) in substantia nigra by the way of western blotting and immunofluorescence. ALA reduced LID in a dose‑dependent manner without compromising the anti‑PD effect of L‑DOPA. Moreover, ALA reduced the level of MDA and upregulated the GSH activity, as well as ameliorated IBa‑1 positive neurons in the substantia nigra. Finally, it was identified that ALA could reduce L‑DOPA‑induced cleaved‑caspase‑3 and PARP overexpression in the substantia nigra. Based on the present findings, ALA could be recommended as a promising disease‑modifying therapy when administered with L‑DOPA early in the course of PD. The exact mechanism for this action, although incompletely understood, appears to relate to anti‑oxidative stress and anti‑apoptosis.

Abstract 4405: Over-expression of PARP is associated with an aggressive phenotype and can be synergistically targeted using combination of PARP and XIAP inhibitors in breast cancer

Abstract Breast cancer is the most common cancer in females and despite improvement in treatment modality with the introduction of hormonal targeted therapy, these cancers still remains a major cause of morbidity and mortality in females. Poly ADP ribose polymerase (PARP) is an enzyme which plays a critical role for repairing single-strand breaks. The main function of PARP1 is dependent upon cellular stress responses and directs cells towards DNA repair based on the strength of the stress stimulus. PARP has been found to be over-expressed in various tumors including ovarian cancer; breast cancer and lung cancer, however, its role in the pathogenesis of breast cancer of Middle Eastern origin have not been completely elucidated. Therefore, we examined the expression of PARP in a large cohort of more than 1000 breast cancer by IHC in a tissue microarray format and found PARP was over expressed in 44.7% (451/1008) and was found to be significantly associated with aggressive markers such as Triple negative phenotype, high grade tumors, large tumor size, stage 4 disease and had a poor 5 year overall survival of 72.6 months as compared to 85.4 months (p = 0.0005). Interestingly PARP expression was also found to be significantly associated with aggressive molecular markers such as activated AKT, XIAP and proliferative marker; ki67. Next, in vitro effect of inactivation of PARP was evaluated using a PARP inhibitor; olaparib on a panel of BC cell lines. Olaparib treatment alone did not affect the cell viability and apoptosis at doses up to 10μM concentration. However, when BC cells were treated with sub-optimal dose of Olaparib (1μM) and Embelin (XIAP inhibitor)(5μM) in combination for 48 hours, there was appreciable inhibition of cell viability via induction of apoptosis. Combination of Olaparib and Embelin induced apoptosis via activation and cleavage of caspases-9, -3 and PARP in BC cells. These studies highlight the importance of targeting PARP in combination with either small molecular inhibitors or chemotherapeutic agents in BC can improve the management and survival of this aggressive disease. Citation Format: Maqbool Ahmed, Azhar R. Hussain, Shaham Beg, Saravanan Thangavel, Rafia Begum, Dahish Ajarim, Fouad Al-Dayel, Abdul Khalid Siraj K. Siraj, Khawla S. Al-kuraya. Over-expression of PARP is associated with an aggressive phenotype and can be synergistically targeted using combination of PARP and XIAP inhibitors in breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4405.

Antitumour activity of 3-nitropropionic acid from Phomopsis sp. and optimization of fermentation conditions.

In this study, 3-nitropropionic acid (3-NPA) was separated and purified from endophytic fungi belonging to Phomopsis sp. and its cytotoxicity was determined by MTT assay. Treatment with 3-NPA for 24h resulted in a dose-dependent apoptosis in MCF-7 cells. Through quantitative detection of the genes that are closely related to the Bcl-2 signalling pathway, there was an increased expression of p53 and Bax and a decreased expression of Bcl-2, which indicated apoptosis in these cells. Meanwhile, the overexpression of PARA (poly ADP-ribose polymerase) and apoptosis inducing factor (AIF) also suggested that 3-NPA induced cellular apoptosis through a caspase-3-independent pathway in caspase-3-deficient MCF-7 cells. The fermentation condition was also improved to produce more 3-NPA: glucose as a carbon source and yeast extract as a nitrogen source, fermentation for 8days at 32°C and a solution environment of pH 5·0. Under these conditions, the yield of 3-NPA was increased to 529mgl(-1) compared with 410mgl(-1) under traditional fermentation conditions. 3-Nitropropionic acid is a mitochondrial inhibitor and has some useful bioactivities such as antibacterial activity. In this paper we found that 3-NPA also has obvious cytotoxicity, so we studied its antitumour activity and tried to determine the antitumour molecular mechanism, opening a new perspective for potential antitumour prodrug development. As 3-NPA is often obtained from natural products with a low yield, in order to overcome thedisadvantage of an endophytic fungi source of 3-NPA, we optimized the fermentation conditions for 3-NPA in Phomopsis sp. to obtain the maximum production of 3-NPA.

Enhanced polyadenosine diphosphate-ribosylation in gonadotropin-releasing hormone agonist-treated uterine leiomyoma.

This study aimed to examine the activation of poly(ADP-ribose) polymerase (PARP) and the accumulation of its end product, poly(ADP-ribose) (PAR), in uterine leiomyoma specimens obtained from 25 patients receiving Leuplin depot [leuprorelin acetate, depot (LA)] treatment and 46 control patients and explore their correlation with tumor shrinkage and degeneration caused by the therapy. Immunoblotting analysis showed that specimens from LA-treated patients had higher PARP expression. The numbers of both PARP- and PAR-immunolabeled cells were higher in leiomyoma with LA treatment. This was correlated with the clinical response of LA therapy that LA induced more leiomyoma degeneration. The analysis of power Doppler sonography indicated a progressive decrease in blood supply to tumor following LA treatment. In vitro experiments using primarily cultured leiomyoma cells exhibited that the deprivation of serum or ovarian hormones or LA directly failed to induce PARP and PAR production. Our results suggested that reduced blood flow and subsequent ischemic damages in leiomyoma could be responsible for PARP overexpression and PAR accumulation, clinical response, and tumor degeneration caused by LA treatment.

Overexpression of Poly(ADP-ribose) Polymerase Disrupts Organization of Cytoskeletal F-actin and Tissue Polarity inDrosophila

Poly(ADP-ribose) polymerase (PARP) may play important roles in nuclear events such as cell cycle, cell proliferation, and maintenance of chromosomal stability. However, the exact biological role played by PARP or how PARP is involved in these cellular functions is still unclear. To elucidate the biological functions of PARP in vivo, we have constructed transgenic flies that overexpress Drosophila PARP in the developing eye primordia. These flies showed mild roughening of the normally smooth ommatidial lattice and tissue polarity disruption caused by improper rotation and chirality of the ommatidia. To clarify how this phenotypical change was induced, here we analyzed transgenic flies overexpressing PARP in the developing eye, embryo, and adult in detail. PARP mRNA level and the phenotype were enhanced in flies carrying more copies of the transgene. Developing eyes from third instar larvae were analyzed by using the neural cell marker to examine the involvement of PARP in cell fate. Morphological disorder of non-neuronal accessory cells was observed in PARP transgenic flies. Interestingly, overexpression of PARP did not interfere with the cell cycle or apoptosis, but it did disrupt the organization of cytoskeletal F-actin, resulting in aberrant cell and tissue morphology. Furthermore, heat-induced PARP expression disrupted organization of cytoskeletal F-actin in embryos and tissue polarity in adult flies. Because these phenotypes closely resembled mutants or transgenic flies of the tissue polarity genes, genetic interaction of PARP with known tissue polarity genes was examined. Transgenic flies expressing either PARP or RhoA GTPase in the eye were crossed, and co-expression of PARP suppressed the effect of RhoA GTPase. Our results indicate that PARP may play a role in cytoskeletal or cytoplasmic events in developmental processes of Drosophila.

Genetic and functional analysis of PARP, a DNA strand break-binding enzyme

Genetic and functional analysis of PARP, a DNA strand break-binding enzyme

Overexpressed poly(ADP‐ribose) polymerase delays the release of rat cells from p53‐mediated G1 checkpoint

We have previously reported that in cells ectopically expressing temperature-sensitive p53135val mutant, p53 formed tight complexes with poly(ADP-ribose) polymerase (PARP). At elevated temperatures, p53135val protein, adopting the mutant phenotype, was localized in the cytoplasm and sequestered the endogenous PARP. To prove whether an excess of p53135val protein led to this unusual intracellular distribution of PARP, we have established cell lines overexpressing p53135val + c-Ha-ras alone or in combination with PARP. Interestingly, immunostaining revealed that PARP is sequestered in the cytoplasm by mutant p53 in cells overexpressing both proteins. Simultaneous overexpression of PARP had no effect on temperature-dependent cell proliferation and only negligibly affected the kinetics of p53-mediated G1 arrest. However, if the cells were completely growth arrested at 32°C and then shifted up to 37°C, coexpressed PARP dramatically delayed the reentry of transformed cells into the cell cycle. Even after 72 h at 37°C the proportion of S-phase cells was reduced to 20% compared to those expressing only p53135val + c-Ha-ras. The coexpressed PARP stabilized wt p53 protein and its enzymatic activity was necessary for stabilization. J. Cell. Biochem. 80:85–103, 2000. © 2000 Wiley-Liss, Inc.

Overexpressed poly(ADP-ribose) polymerase delays the release of rat cells from p53-mediated G1 checkpoint

We have previously reported that in cells ectopically expressing temperature-sensitive p53(135val) mutant, p53 formed tight complexes with poly(ADP-ribose) polymerase (PARP). At elevated temperatures, p53(135val) protein, adopting the mutant phenotype, was localized in the cytoplasm and sequestered the endogenous PARP. To prove whether an excess of p53(135val) protein led to this unusual intracellular distribution of PARP, we have established cell lines overexpressing p53(135val) + c-Ha-ras alone or in combination with PARP. Interestingly, immunostaining revealed that PARP is sequestered in the cytoplasm by mutant p53 in cells overexpressing both proteins. Simultaneous overexpression of PARP had no effect on temperature-dependent cell proliferation and only negligibly affected the kinetics of p53-mediated G(1) arrest. However, if the cells were completely growth arrested at 32 degrees C and then shifted up to 37 degrees C, coexpressed PARP dramatically delayed the reentry of transformed cells into the cell cycle. Even after 72 h at 37 degrees C the proportion of S-phase cells was reduced to 20% compared to those expressing only p53(135val) + c-Ha-ras. The coexpressed PARP stabilized wt p53 protein and its enzymatic activity was necessary for stabilization.

The involvement of poly(ADP-ribose) polymerase in the oxidative stress responses in plants

The involvement of poly(ADP-ribose) polymerase in the oxidative stress responses in plants

Effect of transfection of human poly(ADP-ribose) polymerase in Chinese hamster cells on mutagen resistance

Effect of transfection of human poly(ADP-ribose) polymerase in Chinese hamster cells on mutagen resistance

Expression of recombinant placental prolactin-like protein B in mammalian cells

Expression of recombinant placental prolactin-like protein B in mammalian cells