Expression Of Poly ADP-ribose Polymerase Research Articles

Small Molecular Oligopeptides Adorned with Tryptophan Residues as Potent Antitumor Agents: Design, Synthesis, Bioactivity Assay, Computational Prediction, and Experimental Validation.

Tryptophan participates in important life activities and is involved in various metabolic processes. The indole and aromatic binuclear ring structure in tryptophan can engage in diverse interactions, including π-π, π-alkyl, hydrogen bonding, cation-π, and CH-π interactions with other side chains and protein targets. These interactions offer extensive opportunities for drug development. In this letter, we have designed and synthesized a series of linear oligopeptides adorned with tryptophan residues and identified their potential targets through artificial intelligence-assisted technology and experimental verification. In vitro bioactivity assays revealed that the oligopeptides containing Gly-Pro-Trp residues exhibited promising antitumor activity by inducing autophagy and apoptosis. The PharmMapper pharmacophore mapping approach, molecular docking, and molecular dynamics simulations together identified poly(ADP-ribose) polymerase 1 (PARP1), an enzyme associated with chromatin regulation, as the potential target for the designed compounds. Experimental biolayer interferometry (BLI) and enzyme-linked immunosorbent assay (ELISA) have verified that the oligopeptides could bind with PARP1 and influence PARP1 expression levels. A quantitative structure-activity relationship has been established between the chemical structures of the prepared compounds and their IC50 values. In summary, the research presents a feasible approach for exploring oligopeptide-based antitumor agents.

YY1 drives PARP1 expression essential for PARylation of NONO in mRNA maturation during neuroblastoma progression

BackgroundNeuroblastoma (NB), the most prevalent solid tumor in children, arises from sympathetic nervous system and accounts for 15% of pediatric cancer mortality. This malignancy exhibits substantial genetic and clinical heterogeneity, thus complicating treatment strategies. Poly(ADP-ribose) polymerase 1 (PARP1), a key enzyme catalyzing polyADP-ribosylation (PARylation), plays critical roles in various cellular processes, and contributes to tumorigenesis and aggressiveness. However, the functions and regulatory mechanisms of PARP1 in NB progression still remain to be determined.MethodsThe association of PARP1 expression with NB patients’ survival was analyzed by mining of R2 database. Western blotting, reverse transcription-polymerase chain reaction, MTT colorimetric, soft agar, and matrigel invasion assays were utilized to assess PARP1 expression and its effects on aggressiveness of NB cell lines. Chromatin immunoprecipitation (ChIP) sequencing and ChIP assays were employed to investigate the binding of Yin Yang 1 (YY1) to PARP1 promoter. Protein interactions were explored by BioGRID database analysis, molecular docking, and co-immunoprecipitation assay. RNA sequencing and crosslinking-immunoprecipitation high throughput sequencing datasets were used to identify precursor mRNA splicing targets of non-POU domain containing octamer binding protein (NONO).ResultsHigh PARP1 expression was associated with poor survival of NB patients. PARP1 over-expression enhanced the proliferation and invasion of NB cell lines, confirming its oncogenic roles. YY1 was identified as a key transcriptional regulator facilitating PARP1 expression. Additionally, PARP1 interacted with NONO to induce its PARylation, resulting in stabilization of NONO protein via preventing ubiquitin-mediated degradation. NONO facilitated the splicing and mRNA maturation of target genes a disintegrin and metalloproteinase domain 8 (ADAM8) and testis-expressed gene 14 (TEX14) in a PARylation-dependent manner. Rescue experiments indicated that YY1 facilitated PARP1-mediated PARylation of NONO and subsequent mRNA maturation of ADAM8 and TEX14 in NB cells. In clinical NB cases, high expression of YY1, PARP1, NONO, ADAM8, or TEX14 was associated with poor survival of patients.ConclusionsThese findings indicate that YY1 drives PARP1 expression essential for PARylation of NONO in mRNA maturation during NB progression.

PARP1 promotes tumor proliferation in lenalidomide-resistant multiple myeloma via the downregulation of microRNA-192-5p-AKT signaling.

Lenalidomide-based therapies are recommended as first-line treatment for multiple myeloma (MM) patients, regardless of the transplant eligibility. Resistance to lenalidomide is a clinical problem that urgently needs to be addressed. The expression of poly(ADP-ribose) polymerase 1 (PARP1) is abnormally high in a variety of tumor tissues including MM. However, in lenalidomide-resistant MM, it is not yet known whether the abnormally high expression of PARP1 is involved in the occurrence of drug resistance, and whether the inhibition of PARP1 can reverse lenalidomide resistance. The aim of this study was to investigate the mechanism of PARP1 promoting lenalidomide-resistant in MM patients. Samples of bone marrow from patients with MM who were sensitive or resistant to lenalidomide were collected. The expression levels of PARP1 at the messenger RNA and protein levels were detected through polymerase chain reaction and western blot. MM cell lines were cultivated in vitro, cell lines resistant to lenalidomide were screened out, and the expression levels of PARP1 in the resistant cell lines were detected. The apoptosis level was also detected in the lenalidomide-resistant MM cell lines treated with a PARP1 inhibitor. The proliferation rates of the two groups of cells at different time points were evaluated by mono-methyl terephthalate (MMT) experiments. Finally, the effect of PARP1 on the proliferation of lenalidomide-resistant MM through the microRNA-192-5p-AKT signaling pathway was analyzed. In the lenalidomide-resistant cell lines, the expression level of PARP1 was higher, the proliferation more rapid, and the apoptosis rate was lower than lenalidomide-sensitive cell lines. Additionally, the activated AKT pathway was suppressed by downregulating the expression of microRNA-192-5p. MM resistance can be inhibited to some extent by impacting PARP1. PARP1 is involved in the production of lenalidomide resistance in MM, and could serve as a potential target for the treatment of MM in the future.

Comparative analysis of the primary structure and production of recombinant poly(ADP-ribose)polymerase 1 of long-lived Heterocephalus glaber.

DNA repair is a most important cellular process that helps maintain the integrity of the genome and is currently considered by researchers as one of the factors determining the maximum lifespan. The central regulator of the DNA repair process is the enzyme poly(ADP-ribose)polymerase 1 (PARP1). PARP1 catalyzes the synthesis of poly(ADP-ribose) polymer (PAR) upon DNA damage using nicotinamide adenine dinucleotide (NAD+) as a substrate. This polymer covalently attaches to PARP1, which leads to its dissociation from the complex with damaged DNA and stimulation of the repair process. Despite intensive research on PARP1, its properties as an isolated protein have not been practically studied in mammals that demonstrate a long maximum lifespan, such as, for example, the naked mole rat (Heterocephalus glaber). High activity of DNA repair systems is observed in the cells of the naked mole rat, which ensures their high resistance to oxidative stress, as well as to genotoxic effects. The revealed features may be due to the high activity of PARP1 in the cells of the naked mole rat; however, this issue remains poorly understood and, thus, requires more detailed research, including one with the use of isolated protein PARP1 of the naked mole rat, the isolation and characterization of which have not been carried out before. In the present work, the amino acid sequence of PARP1 of the naked mole rat is compared with the amino acid sequences of orthologous proteins of other mammals. In contrast to human PARP1, 13 evolutionarily conservative amino acid substitutions in various functional domains of the protein have been identified in the amino acid sequence of naked mole rat PARP1. Using the cDNA of the naked mole rat's Parp1 gene, a vector was created for the expression of the target protein in Escherichia coli cell culture. For the first time, a detailed description of the procedure for the expression and purification of the recombinant protein PARP1 of the long-lived naked mole rat is presented. In addition, poly(ADP-ribose)polymerase activity of the obtained protein was evaluated. The results presented in this paper are the basis for further detailed characterization of the properties of purified recombinant naked mole rat PARP1.

Regulation of Alternative Splicing by PARP1 in HTR-8/Svneo Cells: Implications for Placental Development and Spontaneous Abortion.

Alternative splicing affects gene expression during placental development. The present study aimed to identify poly (ADP-ribose) polymerase 1 (PARP1)-regulated alternative splicing events in HTR-8/Svneo cells. Decidual tissues were collected from women with induced abortion and spontaneous abortion. PARP1 transcription was quantified by RT-qPCR. Small interfering RNA (siRNA) was used to knock down the PARP1 expression in HTR-8/Svneo cells. The transfection efficiency was verified by RT-qPCR and Western blotting. Total RNA was extracted, and the RNA-sequencing approach was used to identify alternative splicing events and transcriptomes. The PARP1 knockdown-induced differentially expressed genes with changes in alternative splicing events were quantified by RT-qPCR. Functional analysis, which included the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways, was performed. The PARP1 mRNA expression increased in decidual tissues in the spontaneous abortion group, when compared to the induced abortion group. However, the PARP1 knockdown significantly downregulated 1491 genes and upregulated 881 genes in HTR-8/Svneo cells. Furthermore, 227 genes that underwent alternative splicing were identified, and these were differentially expressed in siPARP1 cells, when compared to siNC cells. The functional analysis revealed that these alternative splicing genes affected the functional phenotypes of extravillous cytotrophoblasts. Furthermore, the PARP1 knockdown led to alterations in gene expression and specific alternative splicing patterns in extravillous trophoblasts.

New TIPARP inhibitor rescues mitochondrial function and brain injury in ischemic stroke

Ischemic stroke is a high-mortality disease that urgently requires new therapeutic strategies. Insufficient cerebral blood supply can induce poly (ADP-ribose) polymerase (PARP) activation and mitochondrial dysfunction, leading to tissue damage and motor dysfunction. We demonstrate that the expression of TCDD inducible PARP (TIPARP) is elevated in ischemic stroke patients and mice. Knockdown of Tiparp reduces brain infarction and promotes recovery of motor function in ischemic stroke mice. A rationally designed TIPARP inhibitor, XG-04-B1, promotes repair of brain injury and recovery of motor function in ischemic stroke mice. Mechanistically, XG-04-B1 increases neuronal plasticity and inhibits astrocyte activation in ischemic stroke mice. In addition, eukaryotic translation initiation factor 3 subunit B (EIF3B) is a direct target of TIPARP. TIPARP interacts with EIF3B through nucleoplasmic redistribution, leading to mitochondrial dysfunction. Knockdown of Tiparp and inhibition of TIPARP via XG-04-B1 restore mitochondrial homeostasis in ischemic stroke mice. Taken together, TIPARP activation contributes to mitochondrial dysfunction and subsequent brain injury, and is therefore a promising therapeutic target for stroke.

Olaparib Enhances the Efficacy of Third-Generation Oncolytic Adenoviruses Against Glioblastoma by Modulating DNA Damage Response and p66shc-Induced Apoptosis.

Patients with glioblastoma multiforme (GBM) do not benefit from current cancer treatments, and their prognosis is dismal. This study aimed to investigate the potential synergistic effects of TS-2021, a third-generation oncolytic adenovirus, combined with the PARP inhibitor olaparib in GBM. TS-2021's impact on p66shc-induced apoptosis, DNA damage response, and poly (ADP-ribose) polymerase (PARP) activation was evaluated in GBM cells. The synergistic effect of TS-2021 and olaparib was examined in GBM cell lines and an immunocompetent mouse model of GBM. Mechanistic studies focused on the role of p66shc phosphorylation in the observed effects. TS-2021 triggered p66shc-induced apoptosis, DNA damage response, and PARP activation. The combination of TS-2021 and olaparib synergistically increased cell apoptosis and DNA damage and reduced PARP expression compared to monotherapy. Olaparib promoted TS-2021 replication and release in GBM cells. Mechanistically, olaparib combined with TS-2021 upregulated p66shc phosphorylation, enhancing tumor cell apoptosis. Invivo, the combination therapy inhibited tumor growth and prolonged survival, confirming the synergistic effect. This study is the first to suggest that TS-2021 sensitizes GBM cells with wild-type BRCA1/2 to olaparib. The combination of TS-2021 and olaparib shows a synergistic therapeutic effect against GBM, providing a promising treatment strategy.

Poly (ADP-Ribose) Polymerase-1 (PARP-1) Inhibitors in Diabetic Retinopathy: An Attractive but Elusive Choice for Drug Development.

Owing to its promiscuous roles, poly (ADP-ribose) polymerase-1 (PARP-1) is involved in various neurological disorders including several retinal pathologies. Diabetic retinopathy (DR) is the most common microvascular complication of diabetes mellitus affecting the retina. In the present review, we highlight the importance of PARP-1 participation in pathophysiology of DR and discuss promising potential inhibitors for treatment. A high glucose level enhances PARP-1 expression; PARP inhibitors have gained attention due to their potential therapeutic effects in DR. They target different checkpoints (blocking nuclear transcription factor (NF-κB) activation; oxidative stress protection, influence on vascular endothelial growth factor (VEGF) expression, impacting neovascularization). Nowadays, there are several improved clinical PARP-1 inhibitors with different allosteric effects. Combining PARP-1 inhibitors with other compounds is another promising option in DR treatments. Besides pharmacological inhibition, genetic disruption of the PARP-1 gene is another approach in PARP-1-initiated therapies. In terms of future treatments, the limitations of single-target approaches shift the focus onto combined therapies. We emphasize the importance of multi-targeted therapies, which could be effective not only in DR, but also in other ischemic conditions.

Poly(ADP-Ribose) Polymerase (PARP) Inhibitors for Cancer Therapy: Advances, Challenges, and Future Directions.

Poly(ADP-ribose) polymerases (PARPs) are crucial nuclear proteins that play important roles in various cellular processes, including DNA repair, gene transcription, and cell death. Among the 17 identified PARP family members, PARP1 is the most abundant enzyme, with approximately 1-2 million molecules per cell, acting primarily as a DNA damage sensor. It has become a promising biological target for anticancer drug studies. Enhanced PARP expression is present in several types of tumors, such as melanomas, lung cancers, and breast tumors, correlating with low survival outcomes and resistance to treatment. PARP inhibitors, especially newly developed third-generation inhibitors currently undergoing Phase II clinical trials, have shown efficacy as anticancer agents both as single drugs and as sensitizers for chemo- and radiotherapy. This review explores the properties, characteristics, and challenges of PARP inhibitors, discussing their development from first-generation to third-generation compounds, more sustainable synthesis methods for discovery of new anti-cancer agents, their mechanisms of therapeutic action, and their potential for targeting additional biological targets beyond the catalytic active site of PARP proteins. Perspectives on green chemistry methods in the synthesis of new anticancer agents are also discussed.

Association of PARP1 Expression Levels and Clinical Parameters in Different Leukemic Subtypes With BCR::ABL1 p190+ Translocation.

Although the reciprocal translocation t(9;22)(q34;q11) is a hallmark of chronic myeloid leukemia (CML), it is also present in acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Depending on the gene's breakpoint, it is possible to obtain three isoforms, among which p190 stands out for the poor prognosis it induces whenever it appears. Due to the genomic instability induced by BCR::ABL1, it is proposed to expand the applicability of poly-ADP-ribose polymerase-1 (PARP1) and its inhibitors in hematological neoplasms. We measured the expression levels of PARP1 by quantitative real-time PCR (qPCR) using TaqMan®, correlating its expression with BCR::ABL1 p190+, to evaluate its influence in the clinic of adult patients. We found that PARP1 is expressed differently in ALL, AML and CML and that p190 transcripts do not follow a linear pattern in these populations. We also found that PARP1 expression is not correlated with age, white blood cell and the amount of p190 transcripts. Despite the lack of statistical correlation between the variables analyzed, the role of PARP1 in BCR::ABL1 leukemia cannot be ruled out, given the instability profile promoted by this translocation. Finally, further studies involving a larger sample of patients are needed, as well as investigations into other molecular pathways that may impact on the pathogenesis of different BCR::ABL1 leukemic subtypes.

PARP-1, EpCAM, and FRα as potential targets for intraoperative detection and delineation of endometriosis: a quantitative tissue expression analysis

BackgroundEndometriosis is a gynecological disease characterized by the presence of endometrial tissue in abnormal locations, leading to severe symptoms, inflammation, pain, organ dysfunction, and infertility. Surgical removal of endometriosis lesions is crucial for improving pain and fertility outcomes, with the goal of complete lesion removal. This study aimed to analyze the location and expression patterns of poly (ADP-ribose) polymerase 1 (PARP-1), epithelial cell adhesion molecule (EpCAM), and folate receptor alpha (FRα) in endometriosis lesions and evaluate their potential for targeted imaging.MethodsGene expression analysis was performed using the Turku endometriosis database (EndometDB). By immunohistochemistry, we investigated the presence and distribution of PARP-1, EpCAM, and FRα in endometriosis foci and adjacent tissue. We also applied an ad hoc platform for the analysis of images to perform a quantitative immunolocalization analysis. Double immunofluorescence analysis was carried out for PARP-1 and EpCAM, as well as for PARP-1 and FRα, to explore the expression of these combined markers within endometriosis foci and their potential simultaneous utilization in surgical treatment.ResultsGene expression analysis revealed that PARP-1, EpCAM, and FOLR1 (FRα gene) are more highly expressed in endometriotic lesions than in the peritoneum, which served as the control tissue. The results of the immunohistochemical study revealed a significant increase in the expression levels of all three biomarkers inside the endometriosis foci compared to the adjacent tissues. Additionally, the double immunofluorescence analysis consistently demonstrated the presence of PARP-1 in the nucleus and the expression of EpCAM and FRα in the cell membrane and cytoplasm.ConclusionOverall, these three markers demonstrate significant potential for effective imaging of endometriosis. In particular, the results emphasize the importance of PARP-1 expression as a possible indicator for distinguishing endometriotic lesions from adjacent tissue. PARP-1, as a potential biomarker for endometriosis, offers promising avenues for further investigation in terms of both pathophysiology and diagnostic-therapeutic approaches.

Parthanatos initiated by ROS-induced DNA damage is involved in intestinal epithelial injury during necrotizing enterocolitis

Necrotizing enterocolitis (NEC) involves intestinal epithelial damage and inflammatory response and is associated with high morbidity and mortality in infants. To improve therapeutic prospects, elucidating underlying molecular mechanisms of intestinal epithelial damage during NEC is of the essence. Poly (ADP-ribose) polymerase 1 (PARP1)-dependent parthanatos is a programmed inflammatory cell death. In the present study, the presence of parthanatos-associated proteins PARP1 and poly (ADP-ribose) (PAR), along with high expression of DNA damage-associated biomarkers, 8-hydroxy-2’-deoxyguanosine (8-OHdG) and phosphorylation of histone H2AX (γH2AX), were discovered in the intestinal tissues of NEC infants. Additionally, the upregulated expression of PARP1 and PAR in NEC intestinal tissues correlated distinctly with clinical indices indicative of NEC incidence and severity. Furthermore, we demonstrated that inhibiting the expression of parthanatos-associated proteins, by either pharmacological blockage using 3-aminobenzamide (3-AB), an inhibitor of PARP1, or genetic knockout using Parp1-deficient mice, resulted in substantial improvements in both histopathological severity scores associated with intestinal injury and inflammatory reactions. Moreover, in an in vitro NEC model, reactive oxygen species (ROS)-induced DNA damage promoted the formation of PAR and nuclear translocation of apoptosis-inducing factor (AIF), thus activating PARP1-dependent parthanatos in Caco-2 cells and human intestinal organoids. Our work verifies a previously unexplored role for parthanatos in intestinal epithelial damage during NEC and suggests that inhibition of parthanatos may serve as a potential therapeutic strategy for intervention of NEC.

HBXIP induces PARP1 via WTAP-mediated m6A modification and CEBPA-activated transcription in cisplatin resistance to hepatoma.

Poly (ADP-ribose) polymerase 1 (PARP1) is a DNA-binding protein that is involved in various biological functions, including DNA damage repair and transcription regulation. It plays a crucial role in cisplatin resistance. Nevertheless, the exact regulatory pathways governing PARP1 have not yet been fully elucidated. In this study, we present evidence suggesting that the hepatitis B X-interacting protein (HBXIP) may exert regulatory control over PARP1. HBXIP functions as a transcriptional coactivator and is positively associated with PARP1 expression in tissues obtained from hepatoma patients in clinical settings, and its high expression promotes cisplatin resistance in hepatoma. We discovered that the oncogene HBXIP increases the level of PARP1 m6A modification by upregulating the RNA methyltransferase WTAP, leading to the accumulation of the PARP1 protein. In this process, on the one hand, HBXIP jointly activates the transcription factor ETV5, promoting the activation of the WTAP promoter and further facilitating the promotion of the m6A modification of PARP1 by WTAP methyltransferase, enhancing the RNA stability of PARP1. On the other hand, HBXIP can also jointly activate the transcription factor CEBPA, enhance the activity of the PARP1 promoter, and promote the upregulation of PARP1 expression, ultimately leading to enhanced DNA damage repair capability and promoting cisplatin resistance in hepatoma. Notably, aspirin inhibits HBXIP, thereby reducing the expression of PARP1. Overall, our research revealed a novel mechanism for increasing PARP1 abundance, and aspirin therapy could overcome cisplatin resistance in hepatoma.

18F]F-Poly(ADP-Ribose) Polymerase Inhibitor Radiotracers for Imaging PARP Expression and Their Potential Clinical Applications in Oncology.

Including poly(ADP-ribose) polymerase (PARP) inhibitors in managing patients with inoperable tumors has significantly improved outcomes. The PARP inhibitors hamper single-strand deoxyribonucleic acid (DNA) repair by trapping poly(ADP-ribose)polymerase (PARP) at sites of DNA damage, forming a non-functional "PARP enzyme-inhibitor complex" leading to cell cytotoxicity. The effect is more pronounced in the presence of PARP upregulation and homologous recombination (HR) deficiencies such as breast cancer-associated gene (BRCA1/2). Hence, identifying HR-deficiencies by genomic analysis-for instance, BRCA1/2 used in triple-negative breast cancer-should be a part of the selection process for PARP inhibitor therapy. Published data suggest BRCA1/2 germline mutations do not consistently predict favorable responses to PARP inhibitors, suggesting that other factors beyond tumor mutation status may be at play. A variety of factors, including tumor heterogeneity in PARP expression and intrinsic and/or acquired resistance to PARP inhibitors, may be contributing factors. This justifies the use of an additional tool for appropriate patient selection, which is noninvasive, and capable of assessing whole-body in vivo PARP expression and evaluating PARP inhibitor pharmacokinetics as complementary to the currently available BRCA1/2 analysis. In this review, we discuss [18F]Fluorine PARP inhibitor radiotracers and their potential in the imaging of PARP expression and PARP inhibitor pharmacokinetics. To provide context we also briefly discuss possible causes of PARP inhibitor resistance or ineffectiveness. The discussion focuses on TNBC, which is a tumor type where PARP inhibitors are used as part of the standard-of-care treatment strategy.

Clonorchis sinensis aggravated liver fibrosis by activating PARP-1 signaling to induce parthanatos via DNA damage

Clonorchis sinensis is an important food-borne zoonotic parasite that is highly associated with liver fibrosis and cholangiocarcinoma. Further understanding of the pathogenesis of C. sinensis, especially liver fibrosis, could help us develop novel strategies for controlling clonorchiasis. Poly (ADP-ribose) polymerase-1 (PARP-1) can induce cellular parthanatos which is reported to be involved in liver fibrosis. Currently, whether C. sinensis could activate PARP-1 signaling to induce parthanatos or whether parthanatos play a role in C. sinensis-induced liver fibrosis is not clear. In the present study, the expression of PARP-1 and parthanatos indicators were detected in C. sinensis-infected mouse liver and in human intrahepatic biliary epithelial cells (HiBEpiCs) incubated with excretory/secretory products (ESPs) of C. sinensis. To explore the role of PARP-1 in C. sinensis infection, PARP-1 inhibitor NMS-P118 was used to block PARP-1 expression in vivo and vitro. The mortality rate, body weight, worm load, liver and bile duct lesions as well as PARP-1 and parthanatos indicators in C57BL/6 mice infected with C. sinensis, or in HiBEpiCs incubated with C. sinensis ESPs and NMS-P118 were analyzed and compared to the group without NMS-P118. The results showed that C. sinensis infection induced the activation of PARP-1 signaling as well as the translocation of AIF and MIF into the nucleus in mouse liver. ESPs of C. sinensis could induce PARP-1 up-regulation, ATP depletion and DNA damage in HiBEpiCs, indicating that C. sinensis could induce parthanatos. Inhibiting PARP-1 with NMS-P118 significantly reduced liver fibrosis and the number of larvae, increased the survival rate and body weight gain of the mice infected with C. sinensis. In addition, NMS-P118 decreased the expression of PARP-1 and alleviated ATP depletion as well as DNA damage in HiBEpiCs incubated with ESPs of C. sinensis. Our data indicated that C. sinensis and its ESPs could activate PARP-1 signaling to induce cellular parthanatos. NMS-P118 treatment alleviated liver fibrosis and promoted survival of the mice by inhibiting PARP-1, which suggested that PARP-1 could be used as a potential therapeutic target against clonorchiasis.

Preparation and Evaluation of a Novel 99mTc-Labeled Niraparib Isonitrile Complex as a Potential PARP-1 Imaging Agent.

Poly ADP-ribose polymerase (PARP) plays an important role in the DNA repair process and has become an attractive target for cancer therapy in recent years. Given that niraparib has good clinical efficacy as a PARP inhibitor, this study aimed to develop radiolabeled niraparib derivatives for tumor imaging to detect PARP expression and improve the accuracy of stratified patient therapy. The niraparib isonitrile derivative (CNPN) was designed, synthesized, and radiolabeled to obtain the [99mTc]Tc-CNPN complex with high radiochemical purity (>95%). It was lipophilic and stable in vitro. In HeLa cell experiments, the uptake of [99mTc]Tc-CNPN was effectively inhibited by the ligand CNPN, indicating the binding affinity for PARP. According to the biodistribution studies of HeLa tumor-bearing mice, [99mTc]Tc-CNPN has moderate tumor uptake and can be effectively inhibited, demonstrating its specificity for targeting PARP. The SPECT imaging results showed that [99mTc]Tc-CNPN had tumor uptake at 2 h postinjection. All of the results of this study indicated that [99mTc]Tc-CNPN is a promising tumor imaging agent that targets PARP.

Design, synthesis, and biological evaluation of novel chrysin derivatives as poly(ADP-ribose) polymerase 1 (PARP1) inhibitors for the treatment of breast cancer

In this study, we reported the discovery and structure-activity relationship analysis of chrysin derivatives as a new class of inhibitors targeting poly (ADP-ribose) polymerase 1 (PARP1). Among these derivatives, compound 5d emerged as the most effective chrysin-based inhibitor of PARP1, with an IC50 value of 108 nmol·L−1. This compound significantly inhibited the proliferation and migration of breast cancer cell lines HCC-1937 and MDA-MB-436 by inducing DNA damage. Furthermore, 5d induced apoptosis and caused an extended G1/S-phase in these cell lines. Molecular docking studies revealed that 5d possesses a strong binding affinity toward PARP1. In vivo, in a xenograft model, 5d effectively reduced tumor growth by downregulating PARP1 expression. Overall, compound 5d shows promise as a potential therapeutic agent for the treatment of BRCA wild-type breast cancer.

Inhibition of PARP1 improves cardiac function after myocardial infarction via up-regulated NLRC5

The incidence and mortality rate of myocardial infarction are increasing per year in China. The polarization of macrophages towards the classically activated macrophages (M1) phenotype is of utmost importance in the progression of inflammatory stress subsequent to myocardial infarction. Poly (ADP-ribose) polymerase 1(PARP1) is the ubiquitous and best characterized member of the PARP family, which has been reported to support macrophage polarization towards the pro-inflammatory phenotype. Yet, the role of PARP1 in myocardial ischemic injury remains to be elucidated. Here, we demonstrated that a myocardial infarction mouse model induced cardiac damage characterized by cardiac dysfunction and increased PARP1 expression in cardiac macrophages. Inhibition of PARP1 by the PJ34 inhibitors could effectively alleviate M1 macrophage polarization, reduce infarction size, decrease inflammation and rescue the cardiac function post-MI in mice. Mechanistically, the suppression of PARP1 increase NLRC5 gene expression, and thus inhibits the NF-κB pathway, thereby decreasing the production of inflammatory cytokines such as IL-1β and TNF-α. Inhibition of NLRC5 promote infection by effectively abolishing the influence of this mechanism discussed above. Interestingly, inhibition of NLRC5 promotes cardiac macrophage polarization toward an M1 phenotype but without having major effects on M2 macrophages. Our results demonstrate that inhibition of PARP1 increased NLRC5 gene expression, thereby suppressing M1 polarization, improving cardiac function, decreasing infarct area and attenuating inflammatory injury. The aforementioned findings provide new insights into the proinflammatory mechanisms that drive macrophage polarization following myocardial infarction, thereby introducing novel potential targets for future therapeutic interventions in individuals affected by myocardial infarction.

Poly (Adp-Ribose) Polymerase-1 (PARP-1) Is a Good Prognostic Marker for Pancreatic/Periampullary Cancers.

Periampullary cancer (PAC) is highly aggressive with no effective adjuvant therapy or prognostic markers. Recently, poly (ADP-ribose) polymerase-1 (PARP-1) has emerged as a target in solid cancers, and its relationship with epithelial-mesenchymal transition (EMT) has been observed. However, the relationship between PARP-1 and EMT in PAC has not explored well. We assessed the prognostic significance of PARP-1 in 190 PACs patients and correlated it with EMT markers, including FGF8, FGFR4, MMP2, MMP3, Snail, and ZEB1. Immunohistochemistry for PARP-1 and EMT markers was performed using a tissue microarray. PARP-1 and FGF8 expression were associated with better survival unlike other solid cancers ( P = 0.006 and P = 0.003), and MMP3 and ZEB1 expression were associated with poor prognosis in multivariate and survival analyses ( P = 0.009 and P < 0.001). In addition, PARP-1 is related negatively to Snail but not related with other EMT markers, implying an independent mechanism between PARP-1 and EMT in PACs. PARP-1 and FGF8 are independent good survival markers in PACs unlike other solid cancers. PARP-1 and FGF8 in PACs could not be related to the EMT pathway but must be rather understood in light of similar cancer-protective roles. Further studies are required on EMT-associated immune markers in PACs.

Nicaraven attenuates the acquired radioresistance of established tumors in mouse models via PARP inhibition.

Nicaraven has been reported to inhibit the activity of poly (ADP-ribose) polymerase (PARP). In this study, we investigated the probable ability of nicaraven to attenuate cancer radioresistance during fractionated radiotherapy. Tumor models were established in C57BL/6 mice and BALB/c nude mice by subcutaneous injection of Lewis mouse lung carcinoma cancer cells and A549 human lung cancer cells, respectively. When the tumors had grown to approximately 100 mm3, we initiated fractionated radiotherapy. Nicaraven or saline was administered immediately after each irradiation exposure. Compared to saline treatment, nicaraven administration significantly induced gamma-H2AX foci formation and cell apoptosis in tumors at 1 or 3days after an additional challenge exposure to 10Gy and inhibited tumor growth during the short-term follow-up period, suggesting increased radiosensitivity of cancer cells. Moreover, the expression of PARP in tumor tissue was decreased by nicaraven administration. Our data suggest that nicaraven likely attenuates the acquired radioresistance of cancers through PARP inhibition.