Poly (ADP-ribose): A double-edged sword governing cancer cell survival and death

Poly(ADP-ribose)(PAR),a polymer of ADP-ribose,is synthesized by PAR po-lymerase and is crucial for the survival of cancer cells due to its vital functions in DNA repair and post-translational modifications.Beyond its supportive role,PAR also triggers cancer cell death by excessive accumulation of PAR leading to an energy crisis and parthanatos.This phenomenon underscores the potential of targeting PAR regulation as a novel anticancer strategy,and the rationale would present an engaging topic in the field of anticancer research.Therefore,this editorial provides an overview of the mechanisms determining cancer cell fate,emphasizing the central role of PAR.It further introduces promising methods for modulating PAR concentrations that may pave the way for innovative anticancer therapies.

Low testing rates and high BRCA prevalence: Poly (ADP-ribose) polymerase inhibitor use in Middle East BRCA/homologous recombination deficiency-positive cancer patients

BACKGROUND Poly(ADP-ribose)polymerase inhibitors(PARPis)are approved as first-line therapies for breast cancer gene(BRCA)-positive,human epidermal growth factor receptor 2-negative locally advanced or metastatic breast cancer.They are also effective for new and recurrent ovarian cancers that are BRCA-or homologous recombination deficiency(HRD)-positive.However,data on these mutations and PARPi use in the Middle East are limited.AIM To assess BRCA/HRD prevalence and PARPi use in patients in the Middle East with breast/ovarian cancer.METHODS This was a single-center retrospective study of 57 of 472 breast cancer patients tested for BRCA mutations,and 25 of 65 ovarian cancer patients tested for HRD.These adult patients participated in at least four visits to the oncology service at our center between August 2021 and May 2023.Data were summarized using descriptive statistics and compared using counts and percentages.Response to treatment was assessed using Response Evaluation Criteria in Solid Tumors criteria.RESULTS Among the 472 breast cancer patients,12.1%underwent BRCA testing,and 38.5%of 65 ovarian cancer patients received HRD testing.Pathogenic mutations were found in 25.6%of the tested patients:26.3%breast cancers had germline BRCA(gBRCA)mutations and 24.0%ovarian cancers showed HRD.Notably,40.0%of gBRCA-positive breast cancers and 66.0%of HRD-positive ovarian cancers were Middle Eastern and Asian patients,respectively.PARPi treatment was used in 5(33.3%)gBRCA-positive breast cancer patients as first-line therapy(n=1;7-months progression-free),for maintenance(n=2;>15-months progression-free),or at later stages due to compliance issues(n=2).Four patients(66.6%)with HRD-positive ovarian cancer received PARPi and all remained progression-free.CONCLUSION Lower testing rates but higher BRCA mutations in breast cancer were found.Ethnicity reflected United Arab Emirates demographics,with breast cancer in Middle Eastern and ovarian cancer in Asian patients.

Poly(ADP-ribose) polymerase inhibition reveals a potential mechanism to promote neuroprotection and treat neuropathic pain

Neuropathic pain is triggered by the lesions to peripheral nerves which alter their structure and function. Neuroprotective approaches that jimit the pathological changes and improve the behavioral outcome have been well explained in different experimental models of neuropathy but translation of such strategies to clinics has been disappointing. Experimental evidences revealed the role of free radicals, especially per- oxynitrite after the nerve injury. They provoke oxidative DNA damage and consequent over-activation of the poly（ADP-ribose） polymerase （PARP） upregulates pro-inflammatory pathways, causing bioenergetic crisis and neuronal death. Along with these changes, it causes mitochondrial dysfunction leading to neu- ronal apoptosis. In related preclinical studies agents that neutralize the free radicals and pharmacological inhibitors of PARP have shown benefits in treating experimental neuropathy. This article reviews the in- volvement of PARP over-activation in trauma induced neuropathy and therapeutic significance of PARP inhibitors in the experimental neuropathy and neuropathic pain.

Multiple facets of poly(ADP-ribose) polymerase-1 in neurological diseases

The highly conserved abundant nuclear protein poly （ADP-ribose） polymerase-1 （PARP-1） is activated by DNA damage. PARP-1 activation is associated in DNA repair, cell death and inflammation. Since oxidative stress induced robust DNA damage and wide spread inflamma- tory responses are common pathologies of various CNS diseases, the attention towards PARP-1 as a therapeutic target has been amplifying. This review highlights the multiple roles of PARP- 1 in neurological diseases and po- tential of PARP- 1 inhibitors to enter clinical translation.

Inhibition of poly(ADP-Ribose)polymerase:A promising strategy targeting pancreatic cancer with BRCAness phenotype

The use of chemotherapeutic regimens for the treatment of pancreatic cancer is still limited because pancreatic cancer is usually diagnosed at an advanced stage as a refractory disease in which symptoms are difficult to recognize in the early stages.Furthermore,at advanced stages,there are important challenges to achieve clinical benefit and symptom resolution,even with the use of an expanded spectrum of anticancer drugs.Recently,a point of reduced susceptibility to conventional chemotherapies by breast cancer susceptibility gene(BRCA)mutations led to a new perspective for overcoming the resistance of pancreatic cancer within the framework of increased genome instability.Poly(ADP-Ribose)polymerase(PARP)-1 is an enzyme that can regulate intrinsic functions,such as response to DNA damage.Therefore,in an environment where germline mutations in BRCAs(BRCAness)inhibit homologous recombination in DNA damage,resulting in a lack of DNA damage response,a key role of PARP-1 for the adaptation of the genome instability could be further emphasized.Here,we summarized the key functional role of PARP-1 in genomic instability of pancreatic cancer with the BRCAness phenotype and listed clinical applications and outcomes of PARP-1 inhibitors to highlight the importance of targeting PARP-1 activity.

Poly(ADP-ribose) polymerase-1 gene polymorphism in various Chinese nationalities

Poly （ADP-ribose） polymerase-1 （PARP-1） can exacerbate ischemic brain injury and lessen ischemic neuronal death, which may be associated with PARP-1 polymorphisms. The present study investigated human PARP-1 gene polymorphisms in various Chinese nationalities, the results of which could potentially help in the treatment and prevention of neurologic diseases. Genetic polymorphisms of seven exons in the PARP-1 gene, in 898 Chinese Han, Buyi, Shui, Miao, and Zhuang subjects, were investigated by PCR-single-strand conformation polymorphism. A single-strand conformation polymorphism variant in exons 12, 13, 16, and 17 of the PARP-1 gene was identified in 148 people, with two stationary bands showing three degenerative single strands. Results showed that the PARP-1 gene polymorphisms exist in various nationalities, and may act as a biomarker for susceptibility to disease.

Effect of the regimen of Gaoshan Hongjingtian on the mechanism of poly（ADP-ribose） polymerase regulation of nuclear factor kappa B in the experimental diabetic retinopathy

Background Poly（ADP-ribose） polymerase （PARP） plays an important role in the death of retinal capillary cells in diabetic retinopathy （DR） partly via its regulation of nuclear factor kappa B （NF-κB）. The current study investigated the effect of the regimen of Gaoshan Hongjingtian （RG） on the mechanism of PARP regulation of NF-κB, and demonstrated the possible impact of the RG and Gaoshan Hongjingtian （Rhodiola sachalinensis, RS） on diabetic retinopathy. Methods Wistar rats were made diabetic by administering streptozotocin. They were then assigned to three groups at random. After 2 months, the three groups of these diabetic rats were treated with RS or RG, or untreated. Analyses of expression levels of PARP, NF-κB, and intercellular adhesion molecule-1 （ICAM-1） in the retinas of rats in different groups were performed by Western blotting and immunohistochemical assays, and mRNA levels of NF-κB and ICAM-1 were determined by real-time polymerase chain reaction （PCR）. In addition, the basement membranes of capillaries in the rats＇ retinas were observed using electron microscopy, and diabetes-induced capillary degeneration （ghost pericytes and acellular capillaries） were quantitated. Results From the third month after the injection of streptozotocin, the diabetic rats were given daily RG, RS or tap water separately. The diabetic rats failed to gain weight compared with normal age-matched rats, whereas their glycated hemoglobin levels were significantly increased. After 5 months, the mRNA levels of NF-KB and ICAM-1 and the protein expression of PARP, NF-κB, and ICAM-1 were significantly increased in the retinas of diabetic rats in the untreated group compared with the nondiabetic controls. After 8 months, the number of degenerated retinal capillaries （ghost pericytes and acellular capillaries） was significantly increased in the diabetic rats in the untreated group compared with normal age-matched rats. RG and RS inhibited diabetes-induced over-expression of PARP, NF-KB, and ICAM-1 in the retinas of diabetic rats at the end of 5-month diabetic duration. Treatment using RG and RS significantly inhibited increases in the number of acellular capillaries and pericyte ghosts and suppressed the basement membrane thickening in the retinas of rats with diabetes for 8 months compared with the control diabetic rats. Conclusions These results indicate that PARP plays an important role in the pathogenesis of diabetic retinopathy. RS and RG may have acted on the mechanism of PARP regulation of NF-κB, which suppressed the expression of NF-KB and ICAM-1, and led to the inhibition of retinal capillary degeneration.

Assaying poly(ADP-ribose) polymerase activity in plants by polarographic method

A new method has been developed to assay poly(ADP-ribose) polymerase (PARP) activity in plant tissues through determining the content of nicotinamide (NIC) produced by enzymatic reaction by linear sweeping polarographic method. The detection limit of NIC was 0.03μmol/L, the calibration graph was linear up to 5μmol/L ( r = 0.999). The recoveries were approximately in the range of 92% to 98% and the relative standard deviations were less

Poly （ADP-ribose） polymerase inhibitor reduces heart ischaemia/ reperfusion injury via inflammation and Akt signalling in rats

Background Poly （ADP-ribose） polymerase （PARP） has been proposed to play an important role in the pathogenesis of heart ischaemia/reperfusion （I/R） injury. 3,4-dihydro-5-[4-（1-piperidinyl）butoxy]-l（2H）-isoquinolinone （DPQ）, a potent PARP inhibitor, has cardiac protective effects. Because the underlying mechanisms are not understood, we investigated the effect of DPQ on heart I/R injury and its mechanisms. Methods Studies were performed with I/R rats＇ hearts. DPQ was used to inhibit the activation of PARP. Cardiac function and cellular apoptosis were assessed. The activation of PARP, transcription factor nuclear factor-kappaB （NF-KB）, intercellular adhesion molecule-1 （ICAM-1）, cyclooxygenase-2 （COX-2） and matrix metalloproteinase-9 （MMP-9） were evaluated. We also evaluated expression of Akt and two of its downstream targets, glycogen synthase kinase-313 （GSK- 3β） and forkhead transcription factor FOXO3a. Results Administration of DPQ significantly decreased the activation of PARP and cellular apoptosis from （35±5）% to （20±4）% and simultaneously improved the cardiac function. DPQ reduced the expressions of NF-KB, ICAM-1, COX-2 and MMP-9 in rat heart and facilitated the activations of phosphor-Akt, phosphor-GSK-3β and phosphor-FOXO3a. Conclusion The protective effects of DPQ were associated with the suppression of inflammation and the activation of the Akt signalling pathways suggesting that the inhibition of poly （ADP-ribose） polymerase reduced heart I/R injury in rats.

Association of poly(ADP-ribose) polymerase activity in circulating mononuclear cells with myocardial dysfunction in patients with septic shock

Background Severe sepsis and septic shock are the leading causes of morbidity and mortality in hospitalized patients.This study aimed to investigate the association of poly（ADP-ribose） polymerase-1 （PARP-1） activity in circulating mononuclear cells with myocardial dysfunction in patients with septic shock.Methods A total of 64 patients with septic shock were divided into the survival group （n=41） and the nonsurvival group （n=23） according to mortality at 28 days after enrollments.PARP-1 activity in circulating mononuclear cells,brain natriuretic peptide,Acute Physiology and Chronic Health Evaluation Ⅱ score,the cardiac index （CI）,the cardiac function index （CFI）,global ejection fraction （GEF）,and the left ventricular contractility index （dp/dt max） were measured after admission to the intensive care unit.Results PARP-1 activity in circulating mononuclear cells of nonsurvival patients with septic shock was significantly higher than that in survival patients.PARP-1 activity in circulating mononuclear cells was strongly,negatively correlated with the CI,the CFI,GEE and dp/dt max.Multiple Logistic regression analysis showed that PARP-1 activity in circulating mononuclear cells was an independent risk factor of myocardial dysfunction.The optimal cutoff point of PARP-1 activity for predicting 28-day mortality was 942 nmol/L with a sensibility of 78.2% and specificity of 65.1%.Conclusion PARP-1 activity in circulating mononuclear cells is significantly associated with myocardial dysfunction and may have prognostic value in patients with septic shock.

Effects of 3-aminobenzamide on poly(ADP-ribose)polymerase expression,apoptosis and cell cycle progression of HeLa cells after X-ray irradiation

The aim of this paper is to study the changes of apoptosis and cell cycle progression in HeLa cells after the poly(ADP-ribose)polymerase(PARP)was inhibited by its inhibitor 3-aminobenzamide(3-AB)and the mechan-isms of PARP action on HeLa cells damaged by irra-diation.Flow cytometry(FCM)was used to examine the PARP expression and the percentage of apoptotic cells and cell cycle progression.The percentage of HeLa cells with positive expression of PARP protein 2,4,8 and 12 h after administrated with 3-AB was significantly lower than that of the control(P<0.01).The percentages of apoptotic cells in the 3-AB plus irradiation group at the time points of 2,8,12 and 24 h after 2 Gy irradiation were higher than that in the irradiation group(P<0.01 or P<0.05)and the percentage of G2 cells decreased signifi-cantly(P<0.01 or P<0.05).It indicates that 3-AB can rapidly inhibit PARP expression of HeLa cells,promote cell apoptosis and block G2 arrest induced by irradiation.

Programmed Cell Death During Secondary Xylem Differentiation in Eucommia ulmoides

Programmed cell death (PCD) during secondary xylem differentiation in Eucommia ulmoides Oliv. was examined using electron microscopy and by investigation of DNA fragmentation and degradation of caspase-like proteases (CLPs). DNA ladders were detected in developing secondary xylem by gel electrophoresis. DNA fragmentation was further confirmed by using the TdT-mediated dUTP nick-end labeling (TUNEL) method. Western blotting analysis showed that CLPs (caspase-8- and caspase-3-like proteases) and PARP (poly (ADP-ribose) polymerase) were degraded during secondary xylem differentiation. The results thus indicated that secondary xylem differentiation in E ulmoides was a typical process of PCD and the degradation of CLPs might be a constitutive PCD event during secondary xylem differentiation.

慢生型大豆根瘤菌(Bradyrhizobium japonicum)聚羟丁酸合成酶基因(phbC)突变体的构建及其特性

通过转座子Tn5诱变和同源重组 ,构建了BradyrhizobiumjaponicumUSDA110聚羟丁酸合成酶基因 (phbC)突变体 .序列测定确定了转座子插入的精确位置 ,所获得的 4个转座子诱变的质粒其Tn5插在 phbC基因内两个相距仅 9bp的位点 .被Southern和PCR证实的突变体菌株仍能产生相当于野生型菌株 12 .97%～ 2 5 .10 %的PHB ,并且在突变体和野生型菌株总DNA杂交图上都呈现出一条约 5kb的阳性带 ,推测在B .japonicum基因组中存在不止一个聚羟丁酸合成酶基因 .图 3表 4参

影响亚甲基四氢叶酸还原酶和甲硫氨酸合成酶还原酶基因多态性的因素分析

目的了解影响女性亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C位点和甲硫氨酸合成酶还原酶(MTRR)A66G位点基因多态性的因素。方法采用横断面调查研究方法,以湖北省内1 902例女性为对象,采集口腔黏膜上皮细胞,提取DNA,用实时荧光定量PCR技术检测MTHFR和MTRR基因,统计分析不同民族MTHFR和MTRR基因多态性的差异,与其他地区人群的MTHFR和MTRR基因多态性进行比较,并分析不同位点基因多态性之间的关联关系。结果 (1)湖北省汉族女性和少数民族女性在MTHFR C677T和MTRR基因多态性构成差异无统计学意义(P>0.05),而MTHFR A1298C位点基因多态性构成差异有统计学意义(P<0.05)。(2)MTHFR C677T位点的纯合突变基因型TT的频率从南到北呈上升趋势,MTHFR A1298C位点的纯合突变基因型CC的频率从南到北呈下降趋势,而MTRR A66G位点基因多态性在不同地区差异不大。(3)MTHFR C677T位点的纯合突变基因型TT的频率在A1298C位点的正常型、杂合型、纯合突变型中分别为15.9%、0.1%、0.0%,差异有统计学意义(P<0.01);MTHFR C677T位点的纯合突变基因型TT的频率在MTRR A66G位点的正常型、杂合型、纯合突变型中分别为9.4%、5.9%、0.7%,差异无统计学意义(P>0.05)。结论 MTHFR A1298C位点基因多态分布存在民族差异;而MTRR C677T、A1298C位点基因多态分布存在地区差异;同一基因不同位点的基因多态性有关联。

北京红篓菌聚羟基烷酸合成酶基因的克隆与表达

以北京红篓菌基因组DNA为供体 ,pKC5 0 5cosmid质粒为载体系统 ,λ 噬菌体体外包装重组质粒并转染感受态细胞E .coliJM1 0 9,构建了该菌株基因组DNA文库。以聚羟基烷酸 (PHA)合成酶基因通用简并引物扩增的PHA合成酶部分基因为探针 ,经DIG标记后利用菌落原位杂交技术对文库进行筛选 ,获得 3个阳性克隆菌株 ,PCR检测证明这 3个克隆具有PHA合成酶基因片段 ,酶活测定表明

中国人群醛固酮合成酶基因T-344C位点单核苷酸多态性频率分析

目的研究醛固酮合成酶(CYP11B2)基因T-344C单核苷酸多态性(SNP)在中国人群中的分布。方法采用PCR-RFLP法对中国人群进行醛固酮合成酶(CYP11B2)基因T-344CSNP频率分析比较。结果中国人群的醛固酮合成酶(CYP11B2)基因T-344C基因型频率分布:TT型占64.5%,TC型占30.8%,CC型占4.7%;等位基因频率T占79.9%,C占20.1%。各基因型频率、等位基因频率与西班牙人、德国人、苏格兰人、日本人差异非常显著。结论醛固酮合成酶(CYP11B2)基因T-344CSNP频率的分布有明显的种族差异。

一氧化氮合成酶（NOS）基因表达的半定量检测及其应用

参照Ｍａｒｔｉｎ（１９９３）定量ＲＴ－ＰＣＲ方法，建立一种灵敏、简捷、特异的半定量ＮＯＳｍＲＮＡ测定方法；证明了ＮＯＳｍＲＮＡ不仅存在于脑组织，亦广泛分布于心、肾、肺和肝组织中，其中以脑组织含量最高，肾、心次之，除内皮细胞以外平滑肌细胞中亦有ＮＯＳ基因的表达；此外，本工作还观察到自发性高血压大鼠的脑、肾、肝和平滑肌细胞中ＮＯＳｍＲＮＡ水平下降，表示ＮＯＳ基因表达受抑，可能与高血压的病因密切相关。

慢生大豆根瘤菌(Bradyrhizobium japonicum)聚羟丁酸合成酶基因(phbC)的克隆和序列测定

以苜蓿根瘤菌Rm10 2 1的 phaC基因突变体菌株Rm1114 4 (phaC ::Tn5 - 2 33)为受体菌 ,通过功能互补 ,成功地从构建的Bradyrhizobium japonicum USDA110基因文库中 ,筛查到能与Rm1114 4互补 ,使之恢复在以乙酰乙酸为唯一碳源的M9培养基 (M9-AA)平板上 5d形成明显可见菌落 ,以及在MOPS平板上形成粘液型菌落的表型的重组粘粒 pDC2 ;经证实 ,该粘粒带有 phbC基因 .完成了该基因的全序列测定并已在GenBank登记 ,登记号为AY0 775 80 .B .japonicumphbC基因由 180 3碱基对组成 ,GC含量 6 1.8% ,AT含量 38.2 % ;编码 6 0 0个氨基酸 ,Mr=6 6 .95× 10 3 .图 3表 3参

γ-PGA合成酶基因在大肠杆菌中的克隆和表达

研究了γ-PGA合成酶基因pgsBCA在大肠杆菌中的克隆和表达,以pET28a(+)为载体,构建表达载体pET28a(+)-pgsBCA,导入宿主Escherichia coli Rosetta中,诱导使之表达。将发酵液离心去除菌体,得到上清液用旋转蒸发仪浓缩后,采用SDS-PAGE电泳检测重组菌E.coli Rosetta/pET28a-pgsBCA产生的γ-PGA分子量在200-300kDa之间,将产物水解,采用薄层层析法鉴定产物由单一的谷氨酸组成,表明γ-PGA合成酶基因pgsBCA在大肠杆菌中成功表达。

白色链霉菌ε-聚赖氨酸合酶的异源表达及重组菌全细胞合成ε-聚赖氨酸的条件优化

聚赖氨酸是一种典型的同型L-赖氨酸聚合物,具有广谱抗菌活性和抗噬菌体活性,广泛应用于食品和医药行业。该文克隆了经密码子优化的白色链霉菌Streptomyces albulus来源的ε-聚赖氨酸合酶编码基因pls,首次实现了其在食品安全性菌株枯草芽孢杆菌Bacillus subtilis 168中的异源表达。其次,对B.subtilis 168/p MA5-pls重组菌株生产ε-聚赖氨酸的全细胞催化体系进行了优化,结果表明,在L-赖氨酸质量浓度0.5 g/L,初始pH和温度分别为3.0和30℃条件下,ε-聚赖氨酸合酶的转化效果最好。在最优体系条件下,连续转化4 h,ε-聚赖氨酸的产量达到195.1 mg/L,高于已报道的Bacillus subtilis直接发酵生产的ε-聚赖氨酸产量。该研究构建的全细胞催化体系为食品级ε-聚赖氨酸的生产提供了新策略。