The catalytic and non-catalytic functions of PARP1 in cancer biology

PARP1 在癌症生物学中的催化和非催化功能

• 批准号: 10377548
• 负责人: Shan Zha
• 金额: $ 35.87万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10377548
• 关键词: ADP ribosylation; Adenosine Diphosphate Ribose; Affect; Alleles; Animal Model; Binding; Biological; Biology; Breast; Cancer Biology; Catalysis; Catalytic Domain; Cells; Cellular biology; Chromatin; Chromosomal Instability; Chromosomal Stability; Clinical; Complex; DNA; DNA Adducts; DNA Binding; DNA Damage; DNA Ligases; DNA Repair; DNA biosynthesis; DNA lesion; DNA strand break; Development; Dominant-Negative Mutation; Embryo; Epigenetic Process; Event; Family member; Female; Fingers; Future; Gender; Genetic; Genetic Transcription; Genome Stability; Goals; Histones; Hypersensitivity; Knock-in; Link; Malignant Neoplasms; Molecular Biology; Mus; Mutation; Ovarian; Pathway interactions; Physiological; Poly Adenosine Diphosphate Ribose; Poly(ADP-ribose) Polymerases; Proteins; Radiation; Radiation Tolerance; Radiation-Sensitizing Agents; Reactive Oxygen Species; Resistance; Role; Sex Bias; Single Strand Break Repair; Site; Testing; Therapeutic Effect; Therapeutic Intervention; Transferase; Woman; X Chromosome; X Inactivation; XRCC1 gene; base; brca gene; cancer cell; cancer radiation therapy; cancer therapy; cancer type; cytotoxicity; demethylation; desensitization; epigenetic regulation; experimental study; genetic approach; genotoxicity; in vivo; inhibitor; male; mouse genetics; mouse model; negative affect; novel; novel anticancer drug; prevent; protein expression; recruit; repaired; response; structural biology; tumorigenesis

Cancer radiation therapy generates DNA lesions and reactive oxygen species, which activate Poly ADP-ribose polymerase 1 (PARP1) and its related family member PARP2. Activated PARP1/2 transfers ADP- Ribose to themselves and histones. The resulted poly (ADP-ribose) (PAR) chains further recruit others repair proteins (e.g. XRCC1-Lig3 complex). Specific inhibitors for both PARP1 and 2 (refer to as PARPi) preferentially target BRCA1/2 deficient cancer cells and synergize with other genotoxic cancer therapies, including radiation. While these effects were originally attributed to the lack of PAR dependent recruitment of XRCC1, deletion of XRCC1 does not have the same cytotoxicity as PARPi. More recently PARPi was found to trap PARP1 at DNA breaks, converting transient PARP1 foci (<10min) to durable ones (>30 min). If not removed, the PARP1-DNA adduct can prevent DNA repair and stall replication. Accordingly PARP1 deletion “desensitizes” cancer cells to PARPi, revealing a structural function of PARP1 in cancer therapy. In preliminary studies, we found unexpectedly the release of PARP1 from DNA is regulated by PARP2 and mono-ADP-ribosylation (MARylation), but not PARylation. To understand this structural function of PARP1 in vivo, we generated mouse models expressing constitutive (Parp1A) or inducible (Parp1AN) PARylation defective PARP1 (E988A) and a conditional PARP1 mouse model (Parp1C). In contrast to the normal development and gender distribution of Parp1-/- mice, Parp1+/A mice display female specific embryonic lethality. And male Parp1+/A cells display severe hypersensitivity to DNA damage agents beyond what is found in Parp1-/- ctrl. Given the application of PARP inhibitor in cancer types almost exclusively affecting women (breast and ovarian), this gender bias is intriguing and might be caused by the breaks independent binding of PARP1 on the chromatin and an role of PARP1 protein in X-inactivation and other epigenetic regulation. Female Parp1+/-Parp2-/- (but not Parp1-/-Parp2+/-) mice also display female specific lethality accompanied by X-chromosome specific instability. Based on these findings, we hypothesize that PARP1 has structural function in chromatin biology and DNA repair that are critical for cancer therapy. To test this, we will use mouse genetics, structural biology and cell biology approaches to 1) determine the mechanism that regulates PARP1 dynamics at DNA damage sites, reveal the biological consequence of PARP1 trapping and 2) characterize PARP1 E988A mouse models to determine the impact of catalytic inactive PARP1 on DNA repair, X-inactivation, oncogenesis in vivo. The completion of this study will elucidate the previously un-recognized structural function of PARP1, reveal functional interactions between PARP1 and PARP2 and the gender specific role of PARP1 in female. In the near future, the mechanism and the novel animal models generated in the course of our study will also facilitate the development and use of PARP inhibitors for cancer therapy.

癌症辐射疗法会产生DNA病变和活性氧，从而激活多聚 ADP-核糖聚合酶1（PARP1）及其相关的家庭成员PARP2。激活的PARP1/2转移ADP- 对自己和组蛋白的核糖。由此产生的聚（ADP-核糖）（PAR）链进一步募集其他维修 蛋白质（例如XRCC1-LIG3复合物）。 PARP1和2（称为PARPI）的特异性抑制剂优先 靶标BRCA1/2缺陷癌细胞，并与其他遗传毒性癌症疗法（包括辐射）协同作用。 尽管这些效果最初归因于缺乏XRCC1的依赖性募集，但删除 XRCC1的细胞毒性与PARPI没有相同的细胞毒性。最近发现PARPI在DNA处捕获PARP1 断裂，将瞬态PARP1灶（<10分钟）转换为耐用的PARP1灶（> 30分钟）。如果未删除，则PARP1-DNA 加合物可以防止DNA修复和失速复制。根据PARP1的缺失，将癌细胞“脱敏”到 PARPI，揭示了PARP1在癌症治疗中的结构功能。在初步研究中，我们发现 出乎意料的是，从DNA中释放PARP1受PARP2和单ADP-核糖基的调节 （玛丽化），但没有抚养。为了了解PARP1在体内的结构功能，我们生成了 表达本构（PARP1A）或诱导（PARP1AN）的小鼠模型有缺陷的PARP1（E988A） 以及有条件的PARP1小鼠模型（PARP1C）。与正常发展和性别相反 PARP1 - / - 小鼠的分布，PARP1+/A小鼠显示女性特定的胚胎致死性。和雄性PARP1+/A单元 表现出对DNA损伤剂的严重超敏反应，超出了PARP1 - / - CTRL中的损伤剂。鉴于 PARP抑制剂在癌症类型中的应用几乎完全影响女性（乳房和卵巢），这 性别偏见很有趣，可能是由于PARP1在染色质上独立的断裂引起的 PARP1蛋白在X灭活和其他表观遗传调节中的作用。女性PARP1 +/- PARP2 - / - （但不是 PARP1 - / - PARP2 +/-）小鼠还表现出X-chromosoms特异性不稳定性实现的女性特异性致死性。 基于这些发现，我们假设PARP1在染色质生物学和DNA中具有结构功能 维修对于癌症治疗至关重要。为了测试这一点，我们将使用小鼠遗传学，结构生物学和细胞 生物学方法1）确定调节DNA损伤位点PARP1动态的机制， 揭示PARP1捕获的生物学后果，2）将PARP1 E988A鼠标模型表征到 确定催化不活跃的PARP1对体内DNA修复，X灭活，肿瘤发生的影响。这 这项研究的完成将阐明PARP1的先前未公认的结构功能，揭示 PARP1和PARP2与PARP1在女性中的性别特定作用之间的功能相互作用。在 不久的将来，我们研究过程中产生的机制和新型动物模型也将 促进和使用PARP抑制剂进行癌症治疗。