Levels Of Poly ADP-ribose Polymerase Research Articles

Short-term Uridine Treatment Alleviates Endoplasmic Reticulum Stress via Regulating Inflammation and Oxidative Stress in Lithium-Pilocarpine Model of Status Epilepticus

Background: Status Epilepticus (SE) leads to the development of epilepsy with the contribution of Endoplasmic Reticulum (ER) stress. Uridine, a pyrimidine nucleoside, has been shown to have neuroprotective and antiepileptogenic effects in animal models. This study aimed to determine whether uridine ameliorates ER stress and apoptosis following epileptogenic insult. Secondly, this study aimed to establish the effect of uridine on inflammatory and oxidative stress parameters that contribute to ER stress. Methods: Status epilepticus was induced using lithium-pilocarpine in adult male Sprague-Dawley rats. Following SE termination, rats were treated with uridine, 4-phenylbutyric acid (4-PBA), or saline twice daily for 48 h. Expressions of hippocampal glucose-regulated protein 78 (GRP78), Inositol- Requiring Protein 1 (IRE1α), Protein kinase RNA-like Endoplasmic Reticulum Kinase (PERK), and C/EBP Homologous Protein (CHOP) were determined by western blotting 48 h after SE. Uridine's effects on apoptosis, inflammation or oxidation were evaluated by analyses of cleaved caspase-3 and poly(ADP-ribose) polymerase 1 (PARP1) protein expressions or pro-inflammatory cytokine levels or levels of oxidative stress markers, respectively. Results: Expressions of all ER stress-related proteins significantly increased 48 h after SE. Uridine treatment markedly decreased GRP78, IRE1α, and CHOP levels. A decrease in the PERK level was observed following the administration of 4-PBA; however, uridine had no effect. Cleaved caspase-3 and PARP1 levels were increased in the SHAM group, while uridine and 4-PBA treatment effectively decreased their expressions. Treatment with uridine significantly reduced Myeloperoxidase (MPO) and Malondialdehyde (MDA) levels while tending to increase Catalase (CAT) and Glutathione Peroxidase (GPx) levels. Uridine treatment also significantly attenuated levels of TNF-α and IL-1β, the pro-inflammatory cytokines, which increased 48 h post-SE. Conclusion: Our data indicate that uridine alleviates ER stress after SE. This effect may be attributed to the regulation of inflammation and oxidative stress. Uridine shows promise as a potential preventive agent for epilepsy.

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.

The effects of berberine and curcumin on cardiac, lipid profile and fibrosis markers in cyclophosphamide-induced cardiac damage: The role of the TRPM2 channel.

Cyclophosphamide (CYP) is widely used to treat various types of cancer. In addition to the therapeutic properties of this drug, unfortunately, its side effects are still not fully understood. This study investigated the protective effect of curcumin (CURC) and berberine (BER) on CYP-induced cardiac damage. Thirty-six male rats were equally divided into the control, dimethyl sulfoxide (DMSO), CYP, CYP + CURC, CYP + BER and CYP + BER + CURC groups. Troponin-I, Creatine kinase-myocardial band (CK-MB), total cholesterol, triglyceride levels in serum samples, and reactive oxygen species (ROS), poly(ADP-ribose) polymerase-1 (PARP-1), and transient receptor potential melastatin 2 (TRPM2) channel levels in heart tissue were measured using an enzyme-linked immunoassay (ELISA) kit. In addition, histopathological examination and immunohistochemical investigation of the TRPM2 channel, fibroblast specific protein-1 (FSP1), transforming growth factor-beta- 1 (TGF-β1) and α-smooth muscle actin (α-SMA) expressions were determined in heart tissue. The CYP group's troponin-I, total cholesterol, triglyceride, CK-MB, ROS, PARP-1 and TRPM2 channel levels were higher than in the other groups in the ELISA measurements (p < 0.05). In contrast, these parameters in the group treated with CURC and BER together with CYP were lower than in the CYP group (p < 0.05). Additionally, CUR and BER reduced CYP-induced pathological damage, TRPM2, FSP1, TGF-β1 and α-SMA expressions. The data showed that CYP administration can cause cardiac damage by increasing the TRPM2 channel, TGF-β1, FSP1 and α-SMA expression levels. Therefore, we concluded that CURC and BER administration following CYP application may be used as therapeutic agents to prevent CYP-induced cardiac damage.

HBx integration in diffuse large B-cell lymphoma inhibits Caspase-3-PARP related apoptosis

Diffuse large B-cell lymphoma (DLBCL) is the most common pathological type of non-Hodgkin lymphoma, and is closely associated with hepatitis B virus (HBV) infection status and hepatitis B X (HBx) gene integration. This project investigated the cellular biological effects and molecular mechanisms responsible for lymphomagenesis and the progression of HBx integration in DLBCL. The data showed that clinical DLBCL cells demonstrated HBx integration, and the sequencing analysis of integrated sites validated HBx integration in the constructed HBx-transfected cells. Compared with control cells, HBx-transfected cells had a significantly reduced proportion of mitochondrial membrane potential, signals of chromosomal DNA breaks, and proportion of apoptotic cells. Further studies found that this decreased apoptosis level was associated with a significant reduction of cleaved Caspase-3 and downstream poly ADP-ribose polymerase (PARP) proteins, revealing the molecular mechanisms of HBx-associated apoptosis in DLBCL. Animal experiments also demonstrated that the protein expression of cleaved Caspase-3 and PARP was prominently reduced in HBx-transfected cells from subcutaneous tumors in mice. Furthermore, the HBx-integrated cells in clinical tissues had significantly lower cleaved PARP levels than the HBx-negative samples. Therefore, HBx integration inhibits cell apoptosis through the Caspase-3-PARP pathway in DLBCL indicating a potential biomarker and therapeutic target in HBV related DLBCL.

MiR-21-5p Modulates Airway Inflammation and Epithelial-Mesenchymal Transition Processes in a Mouse Model of Combined Allergic Rhinitis and Asthma Syndrome

Introduction: Combined allergic rhinitis and asthma syndrome (CARAS) is a concurrent allergic symptom of diseases of allergic rhinitis and asthma. However, the mechanism of CARAS remains unclear. The study aimed to investigate the impact of microRNA-21 (miR-21) on CARAS via targeting poly (ADP-ribose) polymerase-1 (PARP-1) and phosphoinositide 3-kinase (PI3K)/AKT pathways. Methods: The levels of miR-21-5p and PARP-1 in CARAS patients were detected by quantitative reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA). An ovalbumin-sensitized mouse model of CARAS was established. And knock down of miR-21-5p was constructed by intranasally administering with miR-21-5p shRNA-encoding adeno-associated virus vector. Airway resistance and airway inflammatory response were detected. ELISA was used to evaluate IL-4/IL-5/IL-13 levels in bronchoalveolar lavage fluid (BALF). Expression levels of E-cadherin, fibronectin, and α-SMA were determined using Western blotting. The levels of PARP-1 and the activation of PI3K/AKT were assayed. Results: Downregulation of miR-21-5p relieved pathophysiological symptoms of asthma including airway hyperreactivity and inflammatory cell infiltration. Downregulation of miR-21-5p significantly reduced the levels of IL4, IL-5, and IL-13 in BALF. Additionally, downregulation of miR-21-5p inhibited the epithelial-mesenchymal transition (EMT) process in CARAS mice. Furthermore, miR-21-5p regulated PARP-1 and was involved in PI3K/AKT activation in CARAS mice. Conclusion: Downregulation of miR-21-5p ameliorated CARAS-associated lung injury by alleviating airway inflammation, inhibiting the EMT process, and regulating PARP-1/PI3K/AKT in a mouse model of CARAS.

Oleoylethanolamide and Palmitoylethanolamide Enhance IFNβ-Induced Apoptosis in Human Neuroblastoma SH-SY5Y Cells.

Oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) are endogenous lipids that act as agonists of the peroxisome proliferator-activated receptor α (PPARα). Recently, an interest in the role of these lipids in malignant tumors has emerged. Nevertheless, the effects of OEA and PEA on human neuroblastoma cells are still not documented. Type I interferons (IFNs) are immunomodulatory cytokines endowed with antiviral and anti-proliferative actions and are used in the treatment of various pathologies such as different cancer forms (i.e., non-Hodgkin's lymphoma, melanoma, leukemia), hepatitis B, hepatitis C, multiple sclerosis, and many others. In this study, we investigated the effect of OEA and PEA on human neuroblastoma SH-SY5Y cells treated with IFNβ. We focused on evaluating cell viability, cell proliferation, and cell signaling. Co-exposure to either OEA or PEA along with IFNβ leads to increased apoptotic cell death marked by the cleavage of caspase 3 and poly-(ADP ribose) polymerase (PARP) alongside a decrease in survivin and IKBα levels. Moreover, we found that OEA and PEA did not affect IFNβ signaling through the JAK-STAT pathway and the STAT1-inducible protein kinase R (PKR). OEA and PEA also increased the phosphorylation of p38 MAP kinase and programmed death-ligand 1 (PD-L1) expression both in full cell lysate and surface membranes. Furthermore, GW6471, a PPARα inhibitor, and the genetic silencing of the receptor were shown to lower PD-L1 and cleaved PARP levels. These results reveal the presence of a novel mechanism, independent of the IFNβ-prompted pathway, by which OEA and PEA can directly impair cell survival, proliferation, and clonogenicity through modulating and potentiating the intrinsic apoptotic pathway in human SH-SY5Y cells.

Exposure to fluoride exacerbates the cognitive deficit of diabetic patients living in areas with endemic fluorosis, as well as of rats with type 2 diabetes induced by streptozotocin via a mechanism that may involve excessive activation of the poly(ADP ribose) polymerase-1/P53 pathway

Epidemiology has shown that fluoride exposure is associated with the occurrence of diabetes. However, whether fluoride affects diabetic encephalopathy is unclear. Elderly diabetic patients in areas with endemic (n = 169) or no fluorosis (108) and controls (85) underwent Montreal Cognitive Assessment. Sprague-Dawley rats receiving streptozotocin and/or different fluoride doses were examined for spatial learning and memory, brain morphology, blood-brain barrier, fasting blood glucose and insulin. Cultured SH-SY5Y cells were treated with 50 mM glucose and/or low- or high-dose fluoride, and P53-knockdown or poly-ADP-ribose polymerase-1 (PARP-1) inhibition. The levels of PARP-1, P53, poly-ADP-ribose (PAR), apoptosis-inducing factor (AIF), and phosphorylated-histone H2A.X (ser139) were measured by Western blotting. Reactive oxygen species (ROS), 8-hydroxydeguanosine (8-OHdG), PARP-1 activity, acetyl-P53, nicotinamide adenine dinucleotide (NAD+), activities of mitochondrial hexokinase1 (HK1) and citrate synthase (CS), mitochondrial membrane potential and apoptosis were assessed biochemically. Cognition of diabetic patients in endemic fluorosis areas was poorer than in other regions. In diabetic rats, fasting blood glucose, insulin resistance and blood-brain barrier permeability were elevated, while spatial learning and memory and Nissl body numbers in neurons declined. In these animals, expression and activity of P53 and PARP-1 and levels of NAD+, PAR, ROS, 8-OHdG, p-histone H2A.X (ser139), AIF and apoptosis content increased; whereas mitochondrial HK1 and CS activities and membrane potential decreased. SH-SY5Y cells exposed to glucose exhibited changes identical to diabetic rats. The changes in diabetic rats and cells treated with glucose were aggravated by fluoride. P53-knockout or PARP-1 inhibition mitigated the effects of glucose with/without low-dose fluoride. Elevation of diabetic encephalopathy was induced by exposure to fluoride and the underlying mechanism may involve overactivation of the PARP-1/P53 pathway.

Poly(ADP-Ribose) Glycohydrolase (PARG) Removes Repressive Poly-ADP Ribose Marks from DNA Polymerase Theta (PolΘ) to Stimulate DNA Double-Strand Breaks Repair in Myeloid Malignancies

Myeloid malignant cells (AML, MPN, CML) expressing oncogenic tyrosine kinases [OTKs: FLT3(ITD), JAK2(V617F), BCR/ABL1, respectively] accumulate DNA damage but altered DNA repair mechanisms protect them from apoptosis. We reported before that formaldehyde generated by altered serine/one-carbon cycle metabolism in malignant cells harboring OTKs contributed to accumulation of toxic DNA-protein crosslinks (DPCs) which were converted to highly lethal DNA double-strand breaks (DSBs). To counteract the toxicity of DSBs, OTKs enhanced the expression of DNA polymerase theta (PolΘ, encoded by POLQ gene), a unique DNA helicase-DNA polymerase fusion protein that promotes error-prone repair of DSBs by a mechanism referred to as PolΘ-mediated DNA end-joining (TMEJ). PolΘ plays an essential role in the initiation and maintenance of hematological malignancies harboring OTKs. Although the cellular activities of PolΘ have been widely studied, little is known about how PolΘ is regulated at the molecular level. For example, whether post-translational modifications of PolΘ are important for its TMEJ activity and regulation is unknown. Poly(ADP-ribose) polymerase 1 (PARP1) dependent poly-(ADP)-ribosylation (PARylation) of proteins is one of the major post-translational modification events involved in the DNA damage response (DDR). PARP1 - the founding member of the poly(ADP-ribose) polymerase family -transfers adenosine diphosphate (ADP)-ribose from nicotinamide adenine dinucleotide (NAD +) to substrate proteins enabling their PARylation. PARylation is tightly controlled by the glycohydrolase activity of poly(ADP-ribose) glycohydrolase (PARG). Thus, interplay between PARP1 and PARG is thought to regulate the PARylation status of relevant DDR proteins and multiple studies demonstrated that both PARP1 and PARG contribute to DDR. Here, we investigated whether the interplay of PARP1 and PARG is important for the regulation of TMEJ and the specific activities of PolΘ in myeloid malignancies harboring OTKs. We found that upon DNA damage OTKs exerted temporal effect on PolΘ, PARP1 and PARG detection in chromatin fractions. While both PolΘ and PARG displayed continuous time-dependent accumulation during 120 min. after irradiation, PARP1 levels sharply increased at 20 min. and dissipated at 120 min. We find that PARP1 binds to and directly PARylates PolΘ in vitro and in cells. However, PARylated PolΘ is unable to perform TMEJ in vitro due to its inability to bind DNA despite its PARylation dependent recruitment to DNA. Hence, PARG is needed to reactivate PolΘ DNA binding and its TMEJ activity by removing repressive PAR marks on PolΘ. In support of this, cellular studies show that PARG is essential for TMEJ and support a two-step mechanism of a PARP1-PARG regulatory axis of PolΘ and TMEJ. In the first step, the rate of PARP1-PolΘ spatiotemporal recruitment to DNA damage foci supports a rapid step whereby PARP1 PARylates PolΘ and facilitates its recruitment to the vicinity of DNA damage in an inactive state. The rate of PARG spatiotemporal recruitment supports a second step whereby subsequent recruitment of PARG corresponds to dissipation of PARP1 and PAR at DNA damage sites, dePARylation of PolΘ, and activation of TMEJ. These studies elucidate an unprecedented mechanism of PARP1-PARG activation of TMEJ and reveal the molecular basis by which PARP1 and PARG inhibition suppresses TMEJ. In conclusion, using intracellular and biochemical approaches we show here that both PARP1 and PARG are required for TMEJ despite their counteracting enzymatic activities. We also pinpointed a unique dynamic spatiotemporal interplay between PolΘ, PARP1 and PARG to regulate TMEJ activity. During the initial stage, PARP1 activated by DNA damage PARylates PolΘ and facilitates its recruitment to the vicinity of DNA damage. PARG removal of PAR from PolΘ reactivated its interaction with DNA resulting in robust TMEJ activity in vitro and in cells. Thus, DNA/chromatin binding and TMEJ activity of PolΘ were restored upon PARG-mediated removal of PAR repressive marks on PolΘ. This process seems to play a critical role in protecting OTK-positive hematopoietic malignant cells from genotoxic effect of formaldehyde generated by altered serine/one-carbon cycle metabolism.

INVESTIGATION OF ANTIANGIOGENIC AND APOPTOTIC EFFECTS OF GALANTAMINE OBTAINED FROM LEUCOJUM AESTIVUM ON MCF-7 BREAST CANCER CELL LINE

OBJECTIVE: The current study aims to investigate the antiangiogenic and apoptotic effects of galantamine in breast cancer cells and to add new information to the literature. MATERIAL AND METHODS: In this study, MCF-7 breast cancer cell line was used and galantamine was obtained from Leucojum aestivum by HPLC method. The effect of galantamine on cell viability was determined by CCK-8 assay at 9 different doses (control, 10, 40, 70, 100, 130, 160, 190, 210 μg/ml) including the control group. Then, to understand the effect of galantamine, other assays (total antioxidant status (TAS), total oxidant status (TOS), poly-ADP ribose polymerase (PARP), and vascular endothelial growth factor (VEGF) levels) were examined in 3 groups; control, LD50 (100 μg/ml) and high dose (210 μg/ml) group. The oxidative stress index (OSI) was then calculated. RESULTS: Galantamine decreased cell viability. The LD50 dose was determined as 100 μg/ml. There was no significant change in VEGF levels. There was a significant dose-dependent decrease in PARP levels (Control: 2.78667±0.155392, LD50: 1.51000±0.107145, High dose: 1.01000±0.054772 ng/L, p=0.000). Compared to the control group, there was a significant dose-related decrease in TAS data (Control: 0.09633±0.002658, LD50: 0.06283±0.002317, High dose: 0.04050±0.001871, p=0.000) and a significant dose-related increase in TOS data (Control: 0.12500±0.010488, LD50: 0.21667±0.015055, High dose: 0.31833±0.021370, p=0.000). A significant dose-related increase in OSI data was found. (Control: 129.964±13.018, LD50: 345.161±26.480, High dose: 788.485±78.575, p=0.000). CONCLUSIONS: It was determined that galantamine had no significant effect on angiogenesis at any dose based on VEGF levels. Galantamine had a negative effect on cell viability and proliferation at certain doses to MCF-7 cells and was found to increase oxidative stress. The decrease in PARP levels indicates the possibility that cells may result in an apoptotic process. These findings may be useful to take a different approach to the use of galantamine in cancer research.

Inhibitory effect and molecular mechanism of sinomenine on human hepatocellular carcinoma HepG2 and SK-HEP-1 cells

This study aimed to investigate the effect and molecular mechanism of sinomenine on proliferation, apoptosis, metastasis, and combination with inhibitors in human hepatocellular carcinoma HepG2 cells and SK-HEP-1 cells. The effect of sinomenine on the growth ability of HepG2 and SK-HEP-1 cells were investigated by CCK-8 assay, colony formation assay, and BeyoClick~(TM) EdU-488 staining. The effect of sinomenine on DNA damage was detected by immunofluorescence assay, and the effect of sinomenine on apoptosis of human hepatocellular carcinoma cells was clarified by Hoechst 33258 staining and CellEvent~(TM) Cystein-3/7Green ReadyProbes~(TM) reagent assay. Cell invasion assay and 3D tumor cell spheroid invasion assay were performed to investigate the effect of sinomenine on the invasion ability of human hepatocellular carcinoma cells in vitro. The effect of sinomenine on the regulation of protein expression related to the protein kinase B(Akt)/mammalian target of rapamycin(mTOR)/signal transducer and activator of transcription 3(STAT3) signaling pathway in HepG2 and SK-HEP-1 cells was examined by Western blot. Molecular docking was used to evaluate the strength of affinity of sinomenine to the target cysteinyl aspartate specific proteinase-3(caspase-3) and STAT3, and combined with CCK-8 assay to detect the changes in cell viability after combination with STAT3 inhibitor JSI-124 in combination with CCK-8 assay. The results showed that sinomenine could significantly reduce the cell viability of human hepatocellular carcinoma cells in a concentration-and time-dependent manner, significantly inhibit the clonogenic ability of human hepatocellular carcinoma cells, and weaken the invasive ability of human hepatocellular carcinoma cells in vitro. In addition, sinomenine could up-regulate the cleaved level of poly ADP-ribose polymerase(PARP), a marker of apoptosis, and down-regulate the protein levels of p-Akt, p-mTOR, and p-STAT3 in human hepatocellular carcinoma cells. Molecular docking results showed that sinomenine had good affinity with the targets caspase-3 and STAT3, and the sensitivity of sinomenine to hepatocellular carcinoma cells was diminished after STAT3 was inhibited. Therefore, sinomenine can inhibit the proliferation and invasion of human hepatocellular carcinoma cells and induce apoptosis, and the mechanism may be attributed to the activation of caspase-3 signaling and inhibition of the Akt/mTOR/STAT3 pathway. This study can provide a new reference for the in-depth research and clinical application of sinomenine and is of great significance to further promote the scientific development and utilization of sinomenine.

PARP-1 improves leukemia outcomes by inducing parthanatos during chemotherapy

Previous chemotherapy research has focused almost exclusively on apoptosis. Here, a standard frontlinedrug combination of cytarabine and idarubicin induces distinct features of caspase-independent, poly(ADP-ribose)polymerase 1 (PARP-1)-mediated programmed cell death "parthanatos" in acute myeloid leukemia (AML) cell lines (n= 3/10 tested), peripheral blood mononuclear cells from healthy human donors (n= 10/10 tested), and primary cell samples from patients with AML (n= 18/39 tested, French-American-British subtypes M4 and M5). A 3-fold improvement in survival rates is observed in the parthanatos-positive versus -negative patient groups (hazard ratio [HR]= 0.28-0.37, p= 0.002-0.046). Manipulation of PARP-1 activity in parthanatos-competent cells reveals higher drug sensitivity in cells that have basal PARP-1 levels as compared with those subjected to PARP-1 overexpression or suppression. The same trends are observed in RNA expression databases and support the conclusion that PARP-1 can have optimal levels for favorable chemotherapeutic responses.

Esomeprazole Alleviates Cisplatin Resistance by Inhibiting the AKT/mTOR Pathway in Ovarian Cancer Cells.

Ovarian cancer is the most lethal malignancy in gynecology. Due to limited treatment strategies and platinum resistance, newer drugs and therapeutic options are needed. Esomeprazole (ESO) has been reported to have multiple anticancer activities in preclinical and clinical research. Therefore, this study aimed to explore the anticancer effects of esomeprazole on ovarian cancer and its underlying molecular mechanisms. CCK-8 and 5-ethynyl-2'-deoxyuridine (EdU) assays were used to detect cell viability and proliferation. The Transwell assay was used to evaluate cell migration and invasion capacity. Flow cytometry was used to detect cell apoptosis. Western blotting and immunofluorescence were used to detect protein expression. ESO effectively inhibited the cell viability, proliferation, invasion, migration, and induced apoptosis of ovarian cancer cells in a concentration-dependent manner. Treatment with ESO decreased the expression of c-MYC, SKP2, E2F1, N-cadherin, vimentin, and matrix metalloproteinase 2 (MMP2), while it increased E-cadherin, caspase3, p53, BAX, and cleaved poly (ADP-ribose) polymerase (PARP) expression, and downregulated the PI3K/AKT/mTOR signaling pathway. Furthermore, ESO combined with cisplatin showed synergistic effects in inhibiting proliferation, invasion, and migration of cisplatin-resistant ovarian cancer cells. The mechanism may be related to the increased inhibition of c-MYC, epithelial-mesenchymal transition (EMT), and the AKT/mTOR signaling pathway and enhanced the upregulation of the pro-apoptotic protein BAX and cleaved PARP levels. Moreover, ESO combined with cisplatin synergistically upregulated the expression of the DNA damage marker γH2A.X. ESO exerts multiple anticancer activities and has a synergistic effect in combination with cisplatin on cisplatin-resistant ovarian cancer cells. This study provides a promising strategy to improve chemosensitivity and overcome resistance to cisplatin in ovarian cancer.

Synthesis and Degradation of Poly(ADP-ribose) in Zebrafish Brain Exposed to Aluminum.

Poly(ADPribosyl)ation is a post-translational protein modification, catalyzed by poly(ADP-ribose) polymerase (PARPs) enzymes, responsible for ADP-ribose polymer synthesis (PAR) from NAD+. PAR turnover is assured by poly(ADPR) glycohydrolase (PARGs) enzymes. In our previous study, the altered histology of zebrafish brain tissue, resulting in demyelination and neurodegeneration also with poly(ADPribosyl)ation hyperactivation, was demonstrated after aluminum (Al) exposure for 10 and 15 days. On the basis of this evidence, the aim of the present research was to study the synthesis and degradation of poly(ADP-ribose) in the brain of adult zebrafish exposed to 11 mg/L of Al for 10, 15, and 20 days. For this reason, PARP and PARG expression analyses were carried out, and ADPR polymers were synthesized and digested. The data showed the presence of different PARP isoforms, among which a human PARP1 counterpart was also expressed. Moreover, the highest PARP and PARG activity levels, responsible for the PAR production and its degradation, respectively, were measured after 10 and 15 days of exposure. We suppose that PARP activation is related to DNA damage induced by Al, while PARG activation is needed to avoid PAR accumulation, which is known to inhibit PARP and promote parthanatos. On the contrary, PARP activity decrease at longer exposure times suggests that neuronal cells could adopt the stratagem of reducing polymer synthesis to avoid energy expenditure and allow cell survival.

Abstract 4886: PARP-1 and γ-GCS inhibitors enhance platinum sensitivity in ovarian cancer

Abstract Background: Ovarian cancer is the most important cause of gynaecological cancer-related mortality globally. Approximately 80% of patients are diagnosed with advanced stage (FIGO stage III-IV) of ovarian cancer. The standard treatment approach for advanced EOC is primary debulking surgery followed by adjuvant chemotherapy using taxanes plus platinum. Resistance to platinum based chemo remains a key reason for treatment failure in advanced epithelial ovarian cancer (EOC). Therapeutic efficacy of Poly [ADP-ribose] polymerase 1 (PARP1) and Gamma-glutamyl cysteine Synthetase (γ-GCS)inhibitors in ovarian cancer remains undefined, either as a single agent or in combination with cisplatin. Material and Methods: We determined the combined effect of PJ34 (PARP1 inhibitor) and BSO (Buthionine-sulfoximine- (γ-GCS inhibitor) with cisplatin in ovarian cancer cell lines (OVSAHO, KURAMOCHI, and IGROV1) by MTT assay. PARP1 and GCS levels were analyzed by western blotting. We employed flow cytometry for cell cycle analysis as well as for apoptosis studies. Analysis was done using Graph Pad Prism-6. Results were considered to be statistically significant when p value was &amp;lt; 0.05. Results and Conclusion: Combination of cisplatin with PJ34 and BSO augmented cisplatin toxicity in vitro by decreasing cell proliferation and enhancing cell cycle block and cell death when compared with either single agent. A significant cell death (p= &amp;lt;0.05) was observed with the combination of cisplatin, BSO and PJ34. Conclusion: In conclusion, our study provide experimental evidence on the combined effect of PARP-1 and GCS inhibition on CDDP-induced cytotoxicity in epithelial ovarian cancer cells. We propose that PARP-1and BSO inhibitors can be combined with cytotoxic chemotherapeutic agents such as CDDP to enhance the cytotoxicity of chemotherapeutic agents and inhibit key signalling pathways involved in cell proliferation and apoptosis. Future comprehensive studies are needed to demonstrate further validation of above combination. Keywords: Ovarian Cancer, cisplatin, PARP-1, PJ34, γ -GCS, β-actin, Glutathione. Abbreviations: Epithelial Ovarian Cancer (EOC), cisplatin (CDDP), Glutathione (GSH), Gamma Glutamyl Cysteine Synthetase (γ-GCS), Poly (ADP ribosyl) polymerase-1 (PARP1), Nucleotide excision repair (NER),homologous repair (HR), Enzyme-linked immunosorbent assay (ELISA), Buthionine Sulfoximine (BSO), Quantitative Polymerase Chain Reaction (qPCR), Peripheral Blood (PB). Propidium Iodide(PI). Citation Format: Luxmi Devi, Ashok Sharma, Lalit Kumar. PARP-1 and γ-GCS inhibitors enhance platinum sensitivity in ovarian cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4886.

Loss of the receptors ER, PR and HER2 promotes USP15-dependent stabilization of PARP1 in triple-negative breast cancer.

Poly(ADP-ribose) polymerase 1 (PARP1) is essential for the progression of several types of cancers. However, whether and how PARP1 is stabilized to promote genomic stability in triple-negative breast cancer (TNBC) remains unknown. Here, we demonstrated that the deubiquitinase USP15 interacts with and deubiquitinates PARP1 to promote its stability, thereby stimulating DNA repair, genomic stability and TNBC cell proliferation. Two PARP1 mutations found in individuals with breast cancer (E90K and S104R) enhanced the PARP1-USP15 interaction and suppressed PARP1 ubiquitination, thereby elevating the protein level of PARP1. Importantly, we found that estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) inhibited USP15-mediated PARP1 stabilization through different mechanisms. ER bound to the USP15 promoter to suppress its expression, PR suppressed the deubiquitinase activity of USP15, and HER2 abrogated the PARP1-USP15 interaction. The specific absence of these three receptors in TNBC results in high PARP1 levels, leading to increases in base excision repair and female TNBC cell survival.

Effect of selenium against doxorubicin-induced oxidative stress, inflammation, and apoptosis in the brain of rats: Role of TRPM2 channel

Doxorubicin (DOX) is widely used as an anticancer drug in humans' various solid and haematological tumours. Although many studies on the toxic effect of DOX are used in different organs, its impact on brain tissue has yet to be adequately studied. This study investigated the protective effect of selenium (Se) and the role of transient receptor potential melastatin‐2 (TRPM2) channel activation against brain damage caused by DOX administration. Sixty rats were randomly divided into the sham, dimethyl sulfoxide (DMSO), DOX, DOX + Se, DOX + N-(p-amylcinnamoyl) anthranilic acid (ACA), and DOX + Se + ACA groups. The reactive oxygen species (ROS), poly [ADP-ribose] polymerase 1 (PARP1), and TRPM2 channel levels in brain tissues were measured by ELISA. In addition, a histopathological examination was performed in the cerebral cortex and hippocampal areas, and the TRPM2 channel, NF-κB, and caspase-3 expression were determined immunohistochemically. The levels of ROS, PARP1 and TRPM2 channel in the DOX group were higher than in the sham and DMSO groups (P &lt; 0.05). However, these parameters were decreased in the in DOX+Se and DOX+ACA groups by the treatments of Se and ACA (P &lt; 0.05). Also, we determined that Se and ACA treatment decreased the NF-κB, caspase-3, and TRPM2 channel expression in the cerebral cortex and hippocampal areas in the DOX-induced rats. The data showed that Se and/or ACA administration together with DOX administration could be used as a protective agent against DOX-induced brain damage.

PARP-1 inhibitor alleviates liver lipid accumulation of atherosclerosis via modulating bile acid metabolism and gut microbes.

Background: The DNA damage repair enzyme, poly(ADP-ribose) polymerase 1 (PARP1), is crucial for lipid and glucose metabolism. However, no evidence has been presented on the relationship between liver lipid accumulation and the PARP1 inhibitor, 3-aminobenzamide (3-AB), in atherosclerosis. Methods: ApoE-/- mice were used to explore the effect of 3-AB on atherosclerotic liver lipid accumulation, and the experiment of Sprague Dawley (SD) rats was designed to determine if the lowering of liver lipid levels by 3-AB was linked to gut bacteria. The levels of bile acid metabolism-related targets were assessed by ELISA, western blotting, and RT-qPCR. The relative abundances of gut microbes and biomarkers were determined using 16S rRNA sequencing analysis. Bile acid levels in the liver and ileum were examined by ultra-performance liquid chromatography-tandem mass spectrometry. The relationship between gut microbes and bile acids was assessed by Spearman's correlation analysis. Results: 3-AB significantly reduced the formation of aortic plaques in apoE-/- mice, according to gross oil red staining. H & E and Oil Red O staining revealed that 3-AB significantly reduced the hepatic lipid droplet area in ApoE-/- mice and SD rats. Compared with the atherosclerosis (ATH) group, 3-AB dramatically decreased the levels of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein-cholesterol (LDL-C) in the serum of SD rats and apoE-/- mice, and the levels of TC, TG, and LDL-C in the serum and liver of apoE-/- mice. Furthermore, in apoE-/- mice and SD rats, 3-AB increased the mRNA and protein levels of farnesoid X receptor (FXR) and bile salt export pump (BSEP) in the liver, while inhibiting the mRNA and protein levels of FXR and fibroblast growth factor 15 (FGF15) in the ileum, respectively. 3-AB clearly inhibited the mRNA and protein levels of PARP1 in the liver and ileum of apoE-/- mice and rats. Following treatment with 3-AB, the levels of conjugated bile acids decreased in the liver of apoE-/- mice and increased in the ileum of SD rats, according to targeted metabolomic analysis. Microbiome sequencing analysis revealed that 3-AB reduced the relative abundance of Lactobacillus, Bifidobacterium, Listeria, Clostridium, Bacillus, and Staphylococcus in the feces of apoE-/- mice, and the relative abundance of Blautia, Clostridium, and Listeria in the feces of SD rats, eventually decreasing the total abundance of 10 bile salt hydrolase-associated gut microbes. According to the correlation analysis, 3-AB regulates bile acid metabolism, which is primarily related to Bifidobacterium. Conclusion: 3-AB alleviated atherosclerosis by modulating the bile acid metabolism and bile salt hydrolase-related gut microbes.

Barhi date (Phoenix dactylifera) extract ameliorates hepatocellular carcinoma in male rats

Hepatocellular carcinoma (HCC) is a malignant tumor with limited treatment options. Given this fact, it may be important to develop new molecular targeted therapies from natural products, especially those which are primary sources of effective anticancer drugs with distinct mechanisms. Moreover, the complementary use of traditional herbs or fruit may increase the possibility of finding curative options for cancer. Here we explore the anticancer effects and possible molecular mechanism of Barhi date extract using an HCC rat model. Thirty two male albino rats were arbitrarily allocated into four groups: a negative control group (NCG); a positive control group (PCG), which received CCl4 (1 ml/kg b.wt./ i.p.) twice a week for three months; a Barhi date extract (400 mg/kg b.wt./day/orally) treatment group (DTG) during the third month of CCl4 administration; and a cisplatin (1.5 mg/kg b.wt./ i.p.) treatment group ( CTG) during the third month of CCl4 administration. After treatment we performed biochemical analyses of all groups to assess relative eukaryotic initiation factor 2 alpha (eIF2α), extracellular signal-regulated kinases (ERKs), protein kinase RNA-like endoplasmic reticulum kinase (PERK), poly (ADP-ribose) polymerase (PARP), and CASPASE 3 protein content, and examined expression of the genes phosphatase and tensin homolog (PTEN) and protein kinase B (AKT). We also performed an immunohistochemistry assay for alpha-fetoprotein (AFP). Our data showed higher PARP and CASPASE3 levels and liver enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], and alkaline phosphatase [ALP]) in the PCG compared to the DTG and the cisplatin treatment group CTG. However, we also found a significant decrease in PTEN in the PCG relative to both the DTG and the CTG. We conclude that the anti-tumor activity of Barhi date extract may be mediated by the inhibition of cell proliferation and apoptosis via the ERK /PARP/caspase3 pathway and the AKT/ PTEN signaling pathways.

Plasma and Peritoneal Poly (ADP-Ribose) Polymerase Levels in Patients with Endometriosis.

The evidence of poly (ADP-ribose) polymerase (PARP) association with the immune response could be coherent with the immunological theory of endometriosis and suggests the possibility of a new research direction. The aim of the study was to evaluate the levels of PARP in plasma and peritoneal fluid of patients with and without endometriosis. It was a multicenter, cross-sectional study. Plasma and peritoneal fluid samples were collected from patients with and without endometriosis during planned laparoscopic procedures in eight clinical centers. In total, 84 samples of plasma and 84 samples of the peritoneal fluid were included in the final analyses. Double-antibody sandwich enzyme-linked immunosorbent assay was performed in order to assess levels of PARP in collected samples. No statistically significant differences regarding the detected levels of PARP in plasma and peritoneal fluid comparing patients with and without endometriosis were observed. Patients with a history of infertility had significantly higher plasma PARP concentrations (p = 0.04). We have not observed the potential role of PARP concentration levels in plasma nor peritoneal fluid as an endometriosis biomarker. We have determined an association between a higher plasma PARP concentration and a history of infertility.

Effect of miltirone on proliferation and apoptosis of leukemia THP-1 cells

To investigate the toxicity and related mechanism of miltirone to human acute myeloid leukemia THP-1 cells. To be specific, the active components and targets of miltirone were retrieved from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP), and the target proteins were converted into standard gene names with UniProt. Acute leukemia-rela-ted target genes were screened from GeneCards and DisGeNET. Venn diagram was constructed with Venny 2.1 to yield the common targets of the disease and the drug. The protein-protein interaction(PPI) network was constructed by STRING and Cytoscape 3.8.2. THP-1 cells in the logarithmic growth phase were treated with dimethyl sulfoxide(DMSO), and 2.5, 5, 10, 15, and 20 μmol·L~(-1) miltirone for 24 h, respectively. The proliferation rate of cells was analyzed by carboxyfluorescein diacetate succinimidyl ester(CFSE), apoptosis rate by flow cytometry with Annexin V-PE/7 AAD staining, and cell morphology by acridine orange staining. Real-time quantitative PCR(qPCR) was employed to detect the mRNA levels of nuclear receptor coactivator 2(NCOA2), poly(ADP-ribose) polymerase-1(PARP1), B-cell lymphoma-2(Bcl-2)-associated X protein(Bax), Bcl-2, and cysteine aspartyl protease-3(caspase-3). The effect of miltirone on apoptosis was detected in presence of caspase inhibitor Z-VAD-FMK. A total of 26 targets of miltirone, 1 046 genes related to acute leukemia, and 6 common targets of the two were screened out. Flow cytometry result showed miltirone at 10 μmol·L~(-1) can inhibit proliferation and promote apoptosis of THP-1 cells. The typical manifestations of apoptosis, such as cell shrinkage, nuclear rupture, and chromatin agglomerate were displayed by acridine orange staining. The decreased mRNA levels of NCOA2 and PARP1 and increased Bax/Bcl-2 ratio and the activity of pro-apoptotic protein caspase-3 were observed. Z-VAD-FMK can attenuate the apoptosis-inducing effect of miltirone. This study indicates that miltirone can inhibit the proliferation and promote the apoptosis of THP-1 cells, by down-regulating NCOA2 and PARP1, raising Bax/Bcl-2 ratio, and activating caspase-3.