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As one of the most common malignant tumors in women,breast cancer has the characteristics of high inc idence,strong invasion,easy recurrence and metastasis.Although the mortality of breast cancer has decreased in recent years,its incidence has not been effectively controlled.Chemoprevention is a kind of preventive measure to reduce the incidence of disease by using natural or synthetic chemical drugs to prevent the asymptomatic high-risk population.At present,only estrogen receptor modulators and aromatase inhibitors are allowed to be used in clinical chemoprevention of breast cancer.Therefore,researcher should actively take measures to find new highefficient,low-toxic chemoprevention agents that take into account the majority of the population.The main purpose of this review is to summarize the mechanisms and related experimental studies of six chemoprevention agents for breast cancer including estrogen receptor modulators,include aromatase inhibitors,aspirin,metformin,flavones and poly(ADP-ribose) polymerases inhibitors.
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Individuals with breast cancer susceptibility genes (BRCA) germline mutations have a significantly increased lifetime risk for breast cancer,BRCA-mutant cancer cells have abnormal homologous recombination repair of DNA.Inhibition of Poly (ADP-ribose) polymerase (PARP) has shown marked benefit for breast cancer with homologous recombination deficiency,whether driven by defects in BRCA1,BRCA2,or other pathway components.Currently,under U.S.Food and Drug Administration approval of PARP inhibitor on ovarian cancer,clinical trials for PARP inhibitor are being conducted to assess whether PARP inhibitor as monotherapy or in combination with other drugs could benefit more breast cancer patients.Besides the studies of PARP inhibitor as monotherapy in breast cancer patients,researches in investigating platinum-PARP inhibitor combination in BRCA mutated breast cancer or triple negative breast cancer were conducted.In addition,many studies of immunotherapy combined with PARP inhibitor in breast cancer are ongoing.However,resistance to PARP inhibitors and the toxicity of the drugs remain challenges.This review will discuss the utility and unsolved problems of PARP inhibitor in breast cancer as well as the potential future directions.
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As one of the most common malignant tumors in women, breast cancer has the characteristics of high incidence, strong invasion, easy recurrence and metastasis. Although the mortality of breast cancer has decreased in recent years, its incidence has not been effectively controlled. Chemoprevention is a kind of preventive measure to reduce the incidence of disease by using natural or synthetic chemical drugs to prevent the asymptomatic high-risk population. At present, only estrogen receptor modulators and aromatase inhibitors are allowed to be used in clinical chemoprevention of breast cancer. Therefore, researcher should actively take measures to find new high-efficient, low-toxic chemoprevention agents that take into account the majority of the population. The main purpose of this review is to summarize the mechanisms and related experimental studies of six chemoprevention agents for breast cancer including estrogen receptor modulators, include aromatase inhibitors, aspirin, metformin, flavones and poly(ADP-ribose) polymerases inhibitors.
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Individuals with breast cancer susceptibility genes(BRCA) germline mutations have a significantly increased lifetime risk for breast cancer, BRCA-mutant cancer cells have abnormal homologous recombination repair of DNA.Inhibition of Poly (ADP-ribose) polymerase (PARP) has shown marked benefit for breast cancer with homologous recombination deficiency, whether driven by defects in BRCA1, BRCA2, or other pathway components. Currently, under U. S.Food and Drug Administration approval of PARP inhibitor on ovarian cancer, clinical trials for PARP inhibitor are being conducted to assess whether PARP inhibitor as monotherapy or in combination with other drugs could benefit more breast cancer patients. Besides the studies of PARP inhibitor as monotherapy in breast cancer patients, researches in investigating platinum-PARP inhibitor combination in BRCA mutated breast cancer or triple negative breast cancer were conducted. In addition, many studies of immunotherapy combined with PARP inhibitor in breast cancer are ongoing. However, resistance to PARP inhibitors and the toxicity of the drugs remain challenges. This review will discuss the utility and unsolved problems of PARP inhibitor in breast cancer as well as the potential future directions.
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Objective To evaluate the role of poly( ADP-ribose) polymerase-1 ( PARP-1) in lung ischemia-reperfusion ( I/R ) injury in rats and the relationship with autophagy. Methods Twenty-four clean-grade healthy male Sprague-Dawley rats, aged 8-12 weeks, weighing 200-240 g, were divided into 3 groups (n=8 each) using a random number table method: sham operation group (S group), lung I/R group ( I/R group) and lung I/R plus PARP-1 inhibitor PJ34 group ( I/R+PJ34 group) . The chest was only opened without clamping the left hilum of lung in group S. Lung I/R injury model was established by clam-ping the left hilum of lung for 45 min followed by 120 min reperfusion in I/R and I/R+PJ34 groups. PJ3410 mg/kg was intraperitoneally injected at 30 min before ischemia in group I/R+PJ34, while the equal volume of normal saline was injected in S and I/R groups. The rats were sacrificed at the end of reperfusion, and lungs were removed for microscopic examination of the pathological changes ( with a light microscope) which were scored and for determination of wet to dry weight ratio ( W/D ratio) , cell apoptosis ( by TUNEL) , ex-pression of PARP-1 activity markers ( PAR) , Bcl-2, Bax, microtubule-associated protein 1 light chain 3Ⅰ ( LC3-Ⅰ) , LC3-Ⅱ and Beclin-1 ( using Western blot ) . The apoptosis index, Bcl-2/Bax ratio and LC3-Ⅱ/LC3-Ⅰ ratio were calculated. Results Compared with S group, the W/D ratio, pathological scores, apoptosis index and LC3-Ⅱ/LC3-Ⅰ ratio were significantly increased, the expression of PAR and Beclin-1 was up-regulated, and Bcl-2/Bax ratio was decreased in I/R and I/R+PJ34 groups (P＜0. 05). Compared with I/R group, the W/D ratio, pathological scores, apoptosis index, and LC3-Ⅱ/LC3-Ⅰratio were significantly decreased, the expression of PAR and Beclin-1 was down-regulated, and Bcl-2/Bax ratio was increased in I/R+PJ34 group ( P＜0. 05) . Conclusion PARP-1 activation is involved in lung I/R inju-ry in rats, and the mechanism may be related to increasing autophagy and inducing cell apoptosis.
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Objective To evaluate the effect of Iduna protein overexpression on poly(ADP-ribose) polymerase 1 ( PARP-1)∕apoptosis-inducing factor ( AIF) pathway during oxygen-glucose deprivation (OGD)-induced damage to hippocampal neurons in neonatal rats. Methods Primarily cultured hippocam-pal neurons of healthy Sprague-Dawley rats born within 24 h were isolated and cultured. Hippocampal neu-rons were divided into 4 groups (n = 40 each) using a random number table: control group (group C), OGD group ( group O), negative control lentivirus group ( group NL) and Iduna protein overexpression group (group IO). OGD was induced by incubating the neurons in glucose-free medium and hypoxic envi-ronment. Negative control lentivirus and recombinant lentivirus overexpressing Iduna were added at 48 h be-fore establishing the model in NL and IO groups, respectively. Neurons were cultured in the normal culture medium for 24 h in group C. The cell survival rate was detected using methyl thiazolyl tetrazolium assay, the lactic dehydrogenase (LDH) leakage rate was measured using colorimetric method, the comet assay was used to detect DNA content in the tail of neurons, and the expression of PARP-1, cytochrome C (Cyt c) and AIF in the nucleus was detecteded by Western blot. Results Compared with group C, the survival rate of neurons was significantly decreased, the LDH leakage rate and DNA content in the tail of neurons were increased, and the expression of PARP-1, Cyt c and AIF was up-regulated in the other three groups (P<0. 05). Compared with group O, the survival rate of neurons was significantly increased, the LDH leakage rate and the DNA content in the tail of neurons was decreased, and the expression of PARP-1, Cyt c and AIF was down-regulated in group IO (P<0. 05), and no significant change was found in group NL (P>0. 05). Compared with the group NL, the survival rate of neurons was significantly increased, and the LDH leakage rate and DNA content in the tail of neurons were decreased, and the expression of PARP-1, AIF and Cyt c was down-regulated in the group IO (P<0. 05). Conclusion Iduna protein overexpression reduces OGD-induced damage to hippocampal neurons through inhibiting PARP-1∕AIF pathway in neonatal rats.
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Objective To observe the improvement effect of grape seed proanthocyanidin extract (GSPE) on myocardial function in rats with myocardial infarction and to explore its mechanism.Methods Myocardial infarction model rats were randomly divided into five groups:model group,GSPE low,middle and high group,poly ADP-ribose polymerase-1 (PARP-1) inhibitor BSI-201 group,with 15 rats in each group,and another 15 rats were as the sham operation control group.Rats in GSPE low,medium and high dose groups were administrated with 100 mg/ml GSPE,200 mg/ml GSPE and 400 mg/ml GSPE respectively;BSI-201 group was given 120 μmol/L BSI-201 of gavage,and the control group and model group were treated with equal volume of normal saline of gavage,1 times a day for 4 weeks.Doppler echocardiography was used to evaluate cardiac function in rats;myocardial infarction volume was detected by three-phenyl tetrazolium chloride (TTC) staining;hematoxylin and eosin (HE) staining was used to detect histopathological changes of myocardial tissue;terminal dexynucleotidyl transferase (TdT) mediated dUTP nick end labeling (TUNEL) assay was used to detect the apoptosis of myocardial cells;Western blot was used to analyze the expressions of Bax,cleaved-caspase3,Bcl-2 and PAR in myocardial tissue.Results Compared with the control group,the heart rate,left ventricular end diastolic pressure,myocardial infarction area and cell apoptosis rate were significantly increased in the model group,and the mean arterial pressure and left ventricular systolic pressure were decreased significantly (P ＜ 0.05);Myocardial cells were broken and necrotic,irregular fibers arranged in the myocardium,and a large number of inflammatory cells were infiltrated;the protein expressions of Bax,cleaved-caspase3 and PAR in myocardial tissues were increased significantly (P ＜ 0.05),and the protein expression of Bcl-2 was significantly decreased (P ＜ 0.05).Compared with the model group,the heart rate,the left ventricular end diastolic pressure,myocardial infarction area and cell apoptosis rate in the GSPE low,middle and high dose groups and the BSI-201 group were significantly decreased,and the mean arterial pressure and the left ventricular systolic pressure were increased significantly (P ＜ 0.05);the degree of histopathological damage was alleviated;the expressions protein of Bax,cleaved-caspase3 and PAR in myocardial tissues were decreased significantly (P ＜ 0.05),and the protein expression of Bcl-2 was increased significantly (P ＜ 0.05).Conclusions Grape seed proanthocyanidin extract may inhibit cardiomyocyte apoptosis and improve myocardial function of rats with myocardial infarction by inhibiting PARP-1 activation.
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<p><b>OBJECTIVE</b>To investigate the role of poly(ADP-ribose) polymerases-1 (PARP-1)-mediated blockade of autophagic flow in myocardial ischemia-reperfusion injury.</p><p><b>METHODS</b>H9c2 cells, a rat cardiac myocyte line, were divided into control group, hypoxia/ reoxygenation model group (H/R group), PARP-1 inhibitor (PJ34) group, and PJ34 + H/R group. The total protein was extracted from the cells in each group to detect the expressions of pADPr, Bax, the DNA damage marker protein p-YH2ax, and autophagic flow-associated proteins LC3BⅡ/LC3Ⅰ, Beclin-1, and P62 using Western blotting.</p><p><b>RESULTS</b>Compared with the control cells, the cells with H/R exhibited significantly increased expressions of pADPr, Bax and p-YH2ax ( < 0.05). The expressions of LC3B Ⅱ, beclin-1 and p62 were also increased significantly in the cells with H/R ( < 0.05), indicating the block of the autophagic flow. The application of PARP-1 inhibitor PJ34 in the cells with H/R significantly inhibited the expressions of pADPr ( < 0.05) and Bax ( < 0.01), and alleviated DNA damage in the cells. PJ34 treatment did not cause significant changes in the expressions of LC3B Ⅱ and beclin-1 but significantly decreased the expression of p62 ( < 0.05) in the cells with H/R.</p><p><b>CONCLUSIONS</b>Block of autophagic flow mediated by PARP-1 activation plays a role in myocardial ischemiareperfusion injury, and inhibition of PARP-1 activity can reverse autophagic flow block to reduce the injury.</p>
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Colon cancer is one of the common malignant tumors of digestive system.In our previous study, it has been demonstrated that colon cancer specific antigen thioredoxin like-2b (Txl-2b) can interact with Ras-related nuclear protein (Ran).However, there are few reports about the role and mechanism of Ran in tumorigenesis of colon cancer.Aims: To investigate the effect of Ran-targeting RNA interference on apoptosis and expressions of caspase-3 and poly(ADP-ribose) polymerase (PARP) in colon cancer cell lines.Methods: 20, 40 and 60 nmol/L siRNA-1 (si-1 group), siRNA-2 (si-2 group), siRNA-3 (si-3 group) targeting to Ran gene and normal control siRNA (NC group) were transfected into colon cancer cell line HCT116 and DLD-1, respectively.The interference efficiency of siRNAs and expressions of caspase-3 and PARP were detected by Western blotting.Cell apoptosis was determined by flow cytometry.Results: 20 nmol/L siRNA-1 and siRNA-2 had the best effect on inhibiting expression of Ran.Early apoptosis rates of HCT116 and DLD-1 cells in si-1 group were significantly higher than those in NC group (19.37%±7.57% vs.4.83%±1.72%;16.53%±3.38% vs.6.27%±3.13%;P all <0.05).Late apoptosis rates of HCT116 and DLD-1 cells in si-1 and si-2 groups were significantly higher than those in NC group (15.97%±3.31%, 16.33%±5.40% vs.6.40%±1.05%;22.93%±1.57%, 11.50%±0.70% vs.6.20%±0.98%;P all <0.05).Compared with NC group, expressions of cleaved caspase-3 (active form) and cleaved PARP (inactive form) were significantly increased in DLD-1 cells of si-1 and si-2 groups.Conclusions: Silencing Ran gene can significantly promote the apoptosis of colon cancer cells, and its mechanism is related to the regulation of caspase-3 and PARP expression.
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ObjectiveTo investigate the protein expression of poly(ADP-ribose) polymerase-1 (PARP-1) and caspase-3 in pancreatic cancer and adjacent tissues. MethodsA total of 66 cancer tissue samples and 113 samples of adjacent tissues were collected from the patients who underwent surgical treatment with a confirmed diagnosis of pancreatic cancer by postoperative pathological examinations in The First Hospital of Lanzhou University from January 2013 to June 2014, and immunohistochemical examinations were performed to measure the expression of PARP-1 and caspase-3 in these samples. The chi-square test was applied for comparison of categorical data between groups. ResultsOf all the 66 samples of pancreatic cancer, 53 had varying degrees of PARP-1 expression, with a positive rate of 803%; of all the 133 samples of adjacent tissues, 39 had PARP-1 expression, with a positive rate of 34.5%; the expression of PARP-1 in the samples of pancreatic cancer was significantly higher than that in the samples of adjacent tissues (χ2=34.79, P＜0.01). The expression of PARP-1 in moderately and poorly differentiated samples of pancreatic cancer (18/25, 72%; 10/14, 71.4%) was significantly higher than that in highly differentiated samples (3/14, 21.4%) (χ2=10.76, P＜0.01). Of all the 66 samples of pancreatic cancer, 47 had varying degrees of caspase-3 expression, with a positive rate of 71.2%; of all the 133 samples of adjacent tissues, 71 had caspase-3 expression, with a positive rate of 62.8%. The expression of caspase-3 in highly differentiated samples of pancreatic cancer (11/18, 61.1%) was significantly higher than that in moderately and poorly differentiated samples (4/20, 20%; 0/9, 0) (χ2=11.44, P＜001). ConclusionThe expression level of PARP-1 in the samples of pancreatic cancer is significantly higher than that in the samples of adjacent tissues, and the strong positive rate of PARP-1 increases with the decrease in the degree of differentiation; the expression of caspase-3 is similar between pancreatic cancer and adjacent tissues, and the strong positive rate of caspase-3 decreases with the decrease in the degree of differentiation. The expression levels of PARP-1 and caspase-3 may be related to the development and progression of pancreatic cancer.
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After renal injury, selective damage occurs in the proximal tubules as a result of inhibition of glycolysis. The molecular mechanism of damage is not known. Poly(ADP-ribose) polymerase (PARP) activation plays a critical role of proximal tubular cell death in several renal disorders. Here, we studied the role of PARP on glycolytic flux in pig kidney proximal tubule epithelial LLC-PK1 cells using XFp extracellular flux analysis. Poly(ADP-ribosyl)ation by PARP activation was increased approximately 2-fold by incubation of the cells in 10 mM glucose for 30 minutes, but treatment with the PARP inhibitor 3-aminobenzamide (3-AB) does-dependently prevented the glucose-induced PARP activation (approximately 14.4% decrease in 0.1 mM 3-AB-treated group and 36.7% decrease in 1 mM 3-AB-treated group). Treatment with 1 mM 3-AB significantly enhanced the glucose-mediated increase in the extracellular acidification rate (61.1±4.3 mpH/min vs. 126.8±6.2 mpH/min or approximately 2-fold) compared with treatment with vehicle, indicating that PARP inhibition increases only glycolytic activity during glycolytic flux including basal glycolysis, glycolytic activity, and glycolytic capacity in kidney proximal tubule epithelial cells. Glucose increased the activities of glycolytic enzymes including hexokinase, phosphoglucose isomerase, phosphofructokinase-1, glyceraldehyde-3-phosphate dehydrogenase, enolase, and pyruvate kinase in LLC-PK1 cells. Furthermore, PARP inhibition selectively augmented the activities of hexokinase (approximately 1.4-fold over vehicle group), phosphofructokinase-1 (approximately 1.6-fold over vehicle group), and glyceraldehyde-3-phosphate dehydrogenase (approximately 2.2-fold over vehicle group). In conclusion, these data suggest that PARP activation may regulate glycolytic activity via poly(ADP-ribosyl)ation of hexokinase, phosphofructokinase-1, and glyceraldehyde-3-phosphate dehydrogenase in kidney proximal tubule epithelial cells.
Subject(s)
Animals , Cell Death , Epithelial Cells , Glucose , Glucose-6-Phosphate Isomerase , Glycolysis , Hexokinase , Kidney , LLC-PK1 Cells , Oxidoreductases , Phosphofructokinase-1 , Phosphopyruvate Hydratase , Poly Adenosine Diphosphate Ribose , Poly(ADP-ribose) Polymerases , Pyruvate Kinase , SwineABSTRACT
Enhanced oxidative stress is a hallmark of cisplatin nephrotoxicity, and inhibition of poly(ADP-ribose) polymerase 1 (PARP1) attenuates oxidative stress during cisplatin nephrotoxicity; however, the precise mechanisms behind its action remain elusive. Here, using an in vitro model of cisplatin-induced injury to human kidney proximal tubular cells, we demonstrated that the protective effect of PARP1 inhibition on oxidative stress is associated with sirtuin 3 (SIRT3) activation. Exposure to 400 µM cisplatin for 8 hours in cells decreased activity and expression of manganese superoxide dismutase (MnSOD), catalase, glutathione peroxidase (GPX), and SIRT3, while it increased their lysine acetylation. However, treatment with 1 µM PJ34 hydrochloride, a potent PARP1 inhibitor, restored activity and/or expression in those antioxidant enzymes, decreased lysine acetylation of those enzymes, and improved SIRT3 expression and activity in the cisplatin-injured cells. Using transfection with SIRT3 double nickase plasmids, SIRT3-deficient cells given cisplatin did not show the ameliorable effect of PARP1 inhibition on lysine acetylation and activity of antioxidant enzymes, including MnSOD, catalase and GPX. Furthermore, SIRT3 deficiency in cisplatin-injured cells prevented PARP1 inhibition-induced increase in forkhead box O3a transcriptional activity, and upregulation of MnSOD and catalase. Finally, loss of SIRT3 in cisplatin-exposed cells removed the protective effect of PARP1 inhibition against oxidative stress, represented by the concentration of lipid hydroperoxide and 8-hydroxy-2'-deoxyguanosine; and necrotic cell death represented by a percentage of propidium iodide–positively stained cells. Taken together, these results indicate that PARP1 inhibition protects kidney proximal tubular cells against oxidative stress through SIRT3 activation during cisplatin nephrotoxicity.
Subject(s)
Humans , Acetylation , Catalase , Cell Death , Cisplatin , Deoxyribonuclease I , Down-Regulation , Glutathione Peroxidase , In Vitro Techniques , Kidney , Lipid Peroxides , Lysine , Oxidative Stress , Plasmids , Poly Adenosine Diphosphate Ribose , Poly(ADP-ribose) Polymerases , Propidium , Sirtuin 3 , Superoxide Dismutase , Transfection , Up-RegulationABSTRACT
ObjectiveTo observe the inhibitory and pro-apoptotic effects of two poly(ADP-ribose) polymerase (PARP-1) inhibitors, AG-014699 and AZD2281, on human hepatoma HepG2 cells and preliminarily explore the mechanism by which AG-014699 induces HepG2 cell apoptosis, and to provide a new therapeutic target for hepatoma. MethodsThe effects of different concentrations of AG-014699 and AZD2281 on HepG2 cell proliferation were determined by MTT assay. The cell apoptosis rate was measured by flow cytometry. The expression levels of caspase-3 and caspase-8 were measured by Western Blot. Inter-group comparison was made by t test. ResultsBoth AG-014699 and AZD2281 suppressed HepG2 cell proliferation in a time- and dose-dependent manner. However, the sensitivity of HepG2 cells to the two PARP-1 inhibitors was different. The half-maximal inhibitory concentrations of AG-014699 and AZD2281 at 48 h determined by MTT assay were about 20 μmol/L and 400 μmol/L, respectively. Flow cytometry and Western blot were not used to evaluate the apoptosis of HepG2 cells exposed to AZD2281 to which these cells were not sensitive. HepG2 cell apoptosis could be induced by 10, 30, and 50 μmol/L AG-014699, and the highest apoptosis rate at 48 h was significantly higher than that of the control group (3100%±2.13% vs 09%±0013%, P＜0.01). Compared with those in the control group, the protein levels of caspase-3 and caspase-8 in HepG2 cells after 48-h exposure to 30, and 50 μmol/L AG-014699 increased. ConclusionThe two PARP-1 inhibitors AG-014699 and AZD2281 can inhibit the proliferation of HepG2 cells, which showed different sensitivities to the two inhibitors. AG-014699 can induce HepG2 cell apoptosis by up-regulating the protein expression of caspase-3 and caspase-8.
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Objective To explore effects of ginsenosides Rg1 on the expression of poly(ADP-ribose) polymerase-1 (PARP-1) and tumor necrosis factor receptor (TNFR) 1 in cortex cells after focal cerebral ischemia in rats. Methods Ninety healthy rats were randomly divided into sham-operative group, focal cerebral ischemia group, ginsenoside Rg 1groups (low, medium and high concentrations) and drug control group. Rats were intraperitoneally injected saline 45 mg/kg, saline 45 mg/kg+ginsenosides Rg1 10, 20 and 40 mg/kg, nimodipine 1 mg/kg 5 d before surgery, respectively. Focal cerebral isch?emia model was made by middle cerebral artery occluding in rats. The neurological deficit score and TTC staining were used to verify the success of the rat model. The expressions of PARP-1 and TNFR1 were evaluated by immunohistochemical meth?od and Western blot technique. Results There were obvious symptoms of neurological deficit and large pale infarct area in focal cerebral ischemia group compared with those of sham-operative group. There were higher percentages of neurological deficit score and infarct area in ginsenosides Rg1 groups and positive control group than those of sham-operative group, but which were lower than those of ischemia group (P<0.05). There were no significant differences between ginsenosides Rg1 groups and positive control group. The positive cells of PARP-1 and TNFR1 were higher in ginsenosides Rg1 low-dose group than those of sham-operative group and positive control group, while ones of medium and high-dose Rg1 group were higher than those of sham-operative group, and were lower than those of ischemia group (P<0.05). Compared with sham-op?erative group, PARP-1 and TNFR1 expression strips were significantly enhanced in ischemia group. Expression strips were higher in ginsenosides Rg1 low-dose group than those of sham-operative group. Expression strips were higher in ginsen?osides Rg1 medium-dose group than those of sham-operative group, but which were lower than those of ischemia group, and ones of high-dose group were lower than ischemia group (P<0.05). Conclusion Ginsenoside Rg1 shows protective effects on focal ischemia injury, which may be related with down-regulation of the expression of PARP-1 and TNFR1.
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Poly (ADP-ribose) polymerase-1 (PARP-1) is a ribozyme that widely exists in the cukaryotic cells.It plays important roles in the maintenance of genomic stability and the regulation of gene transcription and other physiological processes.PARP-1 is overactivated after ischemic brain injury,and PARP-1 gene knockout mice or PARP-1 inhibitor can reduce brain injury in a variety of models of cerebral ischemia.Therefore,PARP-1 plays important roles in the pathophysiologic processes of ischemic brain injury.The investigation of the effect of PARP-1 in cerebral ischemia contributes to further understanding the pathophysiologic mechanism of stroke and finding a new therapeutic target.
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Objective To observe morphological changes of hippocampal CA1 neurons induced by ischemic acute kidney injury (IAKI) in rats.Methods After successful preparation of rat model of IAKI, the morphological changes of hip-pocampal CA1 neurons were observed by light microscope and electron microscope. The expressions of polyADP-ribose polymerases (PARP)-1 and caspase-3 in hippocampal CA1 neurons were detected by immunohistochemical (IHC) staining and Western blot assay.Results Pyknotic neurons in hippocampal CA1 area were found after 60 min ischemia and 24 h re-perfusion in kidney. Results of electron microscope showed that swollen mitochondria and dilated endoplasmic reticule in cy-toplasm and shrinkage nucleus with no pyknotic chromatin in the pyknotic neurons. IHC staining showed the negative cas-pase-3 staining and positive PARP-1 staining in pyknotic neurons. Conclusion The pyknotic neurons induced by IAKI might be mediated by PARP-1.
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Objective: To investigate the effects of doxorubicin on the expressions of DNA-damage/repair-related proteins BRCA1 (breast cancer-associated protein 1) and PARP-1 [poly(ADP-ribose) polymerase-1] in BRCA1 wild-type breast cancer MCF-7 cells. Methods: The MCF-7 cells were treated with doxorubicin, then the expressions of BRCA1 and PARP-1 and the activity of PARP-1 in the cells recovering after different time peroids were detected by Western blotting. The apoptotic rates of MCF-7 cells and SKBR3.0 cells (BRCA1 mutant-type breast cancer cells) after intervention with doxorubicin and PARP-1 inhibitor 3-ABA (3-aminobenzamide) were detected by FCM (flow cytometry). Results: After MCF-7 cells were treated with different concentrations of doxorubicin for 24 h and then recovered for 12 h, the expression of PAR [poly(ADP-ribose)], an active product of PARP-1, was increased in a dose-dependent manner (P 0.05). Both doxorubicin and 3-ABA alone could significantly induce the apoptosis of MCF-7 cells (P < 0.05), and the combination of the two could further increase the apoptosis of BRCA1 wild-type breast MCF-7 cells (P < 0.05). Doxorubicin in combination with 3-ABA could also induce the apoptosis of BRCA1 mutant-type SKBR3.0 cells, and this effect was stronger than that in MCF-7 cells (P < 0.05). Conclusion: Doxorubicin intervention can affect the activity of DNA-damage/repair-related protein PARP-1 and the expression of BRCA1. Both doxorubicin and PARP-1 inhibitor 3-ABA can induce the apoptosis of MCF-7 cells, and the combination of the two can increase this apoptosis-inducing effect. Copyright © 2013 by TUMOR.
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Objective To observe the effects and study the underlying mechanism of siRNA targeting PARP1 on the proliferation of androgen independent prostate cancer PC3 cell line.Methods Three specific siRNA sequences targeting PARP1 were designed and synthesized.And two sequences which had better interfering effect on the expression of PARP1 were evaluated and selected through lipofectamine transfection,RT-PCR and Western Blot.The effect of PARP1 silencing on the proliferation of PC3 cells was observed with MTS assay and the levels of the phosphorylation of Akt and GSK3β were detected by Western Blot.Results Compared to the blank control group,the transfected group with the negative control sequence had no significant impact on the expression of PARP1,however the transfected group with siRNA-1706,-2003 or-2907 could significantly suppress the mRNA and protein expression of PARP1.The mRNA inhibition rate reached to(52.07 ± 4.65)％,(44.38 ± 9.15)％ and(22.05 ± 6.65)％,respectively;and the protein inhibition rate reached to(86.86 ± 4.94)％,(83.30 ± 7.18)％ and(63.05 ± 10.19)％,respectively.The siRNA-1706 and-2003 could significantly inhibit the proliferation of PC3 cells;the inhibition rate was(38.93 ± 3.87)％ and(34.93 ± 1.21)％.And they also could down-regulate the intracellular levels of phosphorylated Akt and GSK3β in PC3 cells.Conclusion PARP1-targeted siRNA can significantly suppress the expression of endogenous PARP1 and inhibit the proliferation of PC3 cells,which is related to the inhibition of Akt activity and the activation of GSK3 β.
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Objective To investigate the effect of Poly (ADP-ribose) polymerase(PARP) in heart ischemia/reperfusion (I/R) injury in rats.Methods Forty - eight rats were divided into 4 groups randomly.3,4 -dihydro-5- [ 4- ( 1 -piperidinyl) butoxy ] - 1 ( 2H ) - isoquinolinone ( DPQ ),an inhibitor of PARP,was used to inhibit the expression of PARP in rat's heart.The expression of PARP,heart infarct size,heart function,and apoptosis of the cardiomyocytes were detected of different groups of the rats.Results The expression of PARP increased in rat heart I/R injury.Mter DPQ was used,the expression of PARP decreased significantly(5.04 ± 1.25 vs 2.33 ± 0.65,t =1.35,P ＜ 0.05 ) ; inhibition of the expression of PARP improved the cardiac function; inhibition of the expression of PARP decreased cells apoptosis from (34 ± 6.2) ％ to (323 ± 3.8) ％ ( t =2.25,P ＜ 0.05).Conclusions The expression of PARP increased in rat heart I/R injury.Inhibition of the expression of PARP could protect the heart from I/R injury.
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Triple-negative breast cancer(TNBC)is a special subtype of breast cancer which is invalid to endocrine therapy.Anti-Her2 targeted therapies such as herceptin and lapatinib are not suitable to TNBC.At present,conventional chemotherapy is the only way for the medical therapy of TNBC.Thus,searching for novel therapeutic agents for TNBC is one of hot researches of breast cancer.New targeted therapy drugs such as PARP-1 inhibitors,EGFR inhibitors,CXCR4 inhibitors,anti-angiogenesis drugs,Src tyrosine kinase inhibitor,and mTOR inhibitor are being researched.