scholarly journals Beyond PARP1: The Potential of Other Members of the Poly (ADP-Ribose) Polymerase Family in DNA Repair and Cancer Therapeutics

Author(s):  
Iain A. Richard ◽  
Joshua T. Burgess ◽  
Kenneth J. O’Byrne ◽  
Emma Bolderson

The proteins within the Poly-ADP Ribose Polymerase (PARP) family encompass a diverse and integral set of cellular functions. PARP1 and PARP2 have been extensively studied for their roles in DNA repair and as targets for cancer therapeutics. Several PARP inhibitors (PARPi) have been approved for clinical use, however, while their efficacy is promising, tumours readily develop PARPi resistance. Many other members of the PARP protein family share catalytic domain homology with PARP1/2, however, these proteins are comparatively understudied, particularly in the context of DNA damage repair and tumourigenesis. This review explores the functions of PARP4,6-16 and discusses the current knowledge of the potential roles these proteins may play in DNA damage repair and as targets for cancer therapeutics.

2018 ◽  
Vol 36 (4_suppl) ◽  
pp. 389-389
Author(s):  
Erkut Hasan Borazanci ◽  
Carol Guarnieri ◽  
Susan Haag ◽  
Ronald Lee Korn ◽  
Courtney Edwards Snyder ◽  
...  

389 Background: Molecular analysis has revealed four subtypes of PC giving clinicians further insight into treating this deadly disease. One subtype that was elucidated termed “unstable” is significant for the presence of DNA damage repair deficiency and can be targeted therapeutically. One such therapy, O, from the drug class poly ADP ribose polymerase (PARP) inhibitors, has already been FDA approved for individuals with BRCA mutated ovarian cancers. We performed a retrospective analysis on patients with PC treated at a single institution who have DNA damage repair deficiency mutations and have been treated with O. Methods: A chart review identified pancreatic cancer patients with DNA repair pathway mutations who were treated with O. The primary objective examined ORR in patients with PC with DNA repair mutations receiving O. Secondary objectives included tolerability, overall survival (OS), CA 19-9 change, and changes in quantitative textural analysis (QTA) on CT. Results: 11 individuals were identified, 5 carriers of a pathogenic germline (g) BRCA2 mutation, 1 carrier of a pathogenic g ATM mutation, 1 carrier of a pathogenic g BRCA1 mutation. Variants of uncertain significance (VUS) included 1 g ATM mutation, 1 g PALB2 mutation, 1 somatic (s) C11orf30 mutation, and 1 s BRCA2 mutation. Median age at diagnosis was 59, with 4 M and 7 F. No patients met criteria for familial PC and 7 had a family history consistent for breast and ovarian cancer syndrome. All individuals had metastatic PC and had progressed on at least 1 line of systemic therapy. ORR was 18%. Median time of therapy on O was 5 months (mo) (Range 1.4 to 29.567 mo) with 5 of the individuals still undergoing treatment at the time of analysis. Mean OS was 12.35 mo, 9 of the 11 individuals still alive. QTA of baseline CTs from subjects with liver (8/11) and pancreatic tumors (7/11) revealed a strong association between lesion texture and OS (Pearson correlation coefficient (PCC): hepatic mets = 0.952, p = 0.0003) and time on O (PCC: panc lesions = 0.889, p = 0.006). Conclusions: In individuals with metastatic PC with mutations involved in DNA repair, O may provide clinical benefit. QTA of individual tumors may allow for additional information that predicts outcomes to PARP inhibitors in this population.


2019 ◽  
Vol 316 (3) ◽  
pp. C299-C311 ◽  
Author(s):  
Jing Luo ◽  
Zhong-Zhou Si ◽  
Ting Li ◽  
Jie-Qun Li ◽  
Zhong-Qiang Zhang ◽  
...  

Hepatocellular carcinoma (HCC) is known for its high mortality rate worldwide. Based on intensive studies, microRNA (miRNA) expression functions in tumor suppression. Therefore, we aimed to evaluate the contribution of miR-146a-5p to radiosensitivity in HCC through the activation of the DNA damage repair pathway by binding to replication protein A3 (RPA3). First, the limma package of R was performed to differentially analyze HCC expression chip, and regulative miRNA of RPA3 was predicted. Expression of miR-146a-5p, RPA3, and DNA damage repair pathway-related factors in tissues and cells was determined. The effects of radiotherapy on the expression of miR-146a-5p and RPA3 as well as on cell radiosensitivity, proliferation, cell cycle, and apoptosis were also assessed. The results showed that there exists a close correlation between miR-146a and the radiotherapy effect on HCC progression through regulation of RPA3 and the DNA repair pathway. The positive rate of ATM, pCHK2, and Rad51 in HCC tissues was higher when compared with that of the paracancerous tissues. SMMC-7721 and HepG2 cell proliferation were significantly inhibited following 8 Gy 6Mv dose. MiR-146a-5p restrained the expression of RPA3 and promoted the expression of relative genes associated with the DNA repair pathway. In addition, miR-146a-5p overexpression suppresses cell proliferation and enhances radiosensitivity and cell apoptosis in HCC cells. In conclusion, the present study revealed that miR-146a-5p could lead to the restriction of proliferation and the promotion of radiosensitivity and apoptosis in HCC cells through activation of DNA repair pathway and inhibition of RPA3.


Folia Medica ◽  
2018 ◽  
Vol 60 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Ashish P. Shah ◽  
Chhagan N. Patel ◽  
Dipen K. Sureja ◽  
Kirtan P. Sanghavi

AbstractThe DNA repair process protects the cells from DNA damaging agent by multiple pathways. Majority of the cancer therapy cause DNA damage which leads to apoptosis. The cell has natural ability to repair this damage which ultimately leads to development of resistance of drugs. The key enzymes involved in DNA repair process are poly(ADP-ribose) (PAR) and poly(ADP-ribose) polymerases (PARP). Tumor cells repair their defective gene via defective homologues recombination (HR) in the presence of enzyme PARP. PARP inhibitors inhibit the enzyme poly(ADP-ribose) polymerases (PARPs) which lead to apoptosis of cancer cells. Current clinical data shows the role of PARP inhibitors is not restricted to BRCA mutations but also effective in HR dysfunctions related tumors. Therefore, investigation in this area could be very helpful for future therapy of cancer. This review gives detail information on the role of PARP in DNA damage repair, the role of PARP inhibitors and chemistry of currently available PARP inhibitors.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 840-840 ◽  
Author(s):  
Danielle N. Yarde ◽  
Lori A. Hazlehurst ◽  
Vasco A. Oliveira ◽  
Qing Chen ◽  
William S. Dalton

Abstract The FA/BRCA pathway is involved in DNA damage repair and its importance in oncogenesis has only recently been implicated. Briefly, 8 FA/BRCA pathway family members facilitate the monoubiquitination of FANCD2. Upon monoubiquitination, FANCD2 translocates to the DNA repair foci where it interacts with other proteins to initiate DNA repair. Previously, we reported that the FA/BRCA pathway is upregulated in multiple myeloma cell lines selected for resistance to melphalan (Chen, et al, Blood 2005). Further, reducing FANCF in the melphalan resistant 8226/LR5 myeloma cell line partially reversed resistance, whereas overexpressing FANCF in the drug sensitive 8226/S myeloma line conferred resistance to melphalan. Others have reported, and we have also verified, that bortezomib enhances melphalan response in myeloma cells; however, the mechanism of enhanced melphalan activity in combination with bortezomib has not been reported. Based on our observation that the FA/BRCA pathway confers melphalan resistance, we hypothesized that bortezomib enhances melphalan response by targeting FA/BRCA DNA damage repair pathway genes. To investigate this hypothesis, we first analyzed FA/BRCA gene expression in 8226/S and 8226/LR5 cells treated with bortezomib, using a customized microfluidic card (to detect BRCA1, BRCA2, FANCA, FANCC, FANCD2, FANCE, FANCF, FANCG, FANCL, RAD51 and RAD51C) and q-PCR. Interestingly, we found that low dose (5nM) bortezomib decreased many FA/BRCA pathway genes as early as 2 hours, with maximal decreases seen at 24 hours. Specifically, 1.5- to 2.5-fold decreases in FANCA, FANCC, FANCD2, FANCE and RAD51C were seen 24 hours post bortezomib exposure. Moreover, pre-treatment of myeloma cells with low dose bortezomib followed by melphalan treatment revealed a greater than 2-fold reduction in FANCD2 gene expression levels. We also found that melphalan treatment alone enhanced FANCD2 protein expression and activation (monoubiquitination), whereas the combination treatment of bortezomib followed by melphalan decreased activation and overall expression of FANCD2 protein. Taken together, these results suggest that bortezomib enhances melphalan response in myeloma by targeting the FA/BRCA pathway. Further understanding of the role of the FA/BRCA pathway in determining melphalan response may allow for more customized and effective treatment of myeloma.


2017 ◽  
Vol 35 (4_suppl) ◽  
pp. 308-308
Author(s):  
Talia Golan ◽  
Sharon Halparin ◽  
Chani Stossel ◽  
Maria Raitses-Gurevich ◽  
Dikla Atias ◽  
...  

308 Background: Approximately 15% of PDAC tumors display DNA damage repair (DDR) deficiency. Germline BRCA (gBRCA) mutation serves as a robust biomarker for the DDR deficiency. A subset of patients displays a similar clinical phenotype but lack the gBRCA mutation. Identification of these BRCA-like subset of patients remains a challenge and an alternative approach may include DDR functional assays. Here we suggest loss of the ATM protein as one of the biomarkers for the identification of the DDR deficiency signature in PDAC. Methods: Patients were identified from the Sheba pancreatic cancer database based on strong family/personal history of BRCA- associated cancers or a durable response to platinum containing regimens ( ≥ 6 month) or harboring germline/somatic mutations in the DNA repair pathway (excluding gBRCA mutation). Archival FFPE blocks of primary tumors/metastatic lesions were used to explore ATM protein expression by IHC. Nuclear staining was regarded as positive. Tumor infiltrating lymphocytes served as an internal positive control. ATM loss was defined as less than10% neoplastic nuclear staining at any intensity in the presence of positive lymphocytes staining. Results: We identified 53 patients with DDR deficiency phenotype between 2014-2016 from the Sheba PDAC database (n = 250). Median age at diagnosis was 65 years (46-81) and the majority were female (62%). 47% were diagnosed at stage I/II and 53% stage IV. In the subgroup of patients with DDR deficiency phenotype, 55% displayed a family history of BRCA-associated cancers, 19% had a personal history of malignancy and23% had known mutation in DNA repair pathway. 23/53 identified subjects have been analyzed to date. We identified 52% loss of ATM in the analyzed group (n = 23). Conclusions: Loss of ATM in an unselected PDAC population is 12% (H. Kim et al, 2014). Our data demonstrate that 52% of the highly selected subgroup of PDAC patients (DDR deficiency phenotype) was found to have loss of ATM protein expression, suggesting it to be one of the biomarker for DDR signature. Identification of these patients, based on ATM protein expression profile may lead to personalized treatment options.


2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 3111-3111
Author(s):  
Biswajit Das ◽  
Yvonne A. Evrard ◽  
Li Chen ◽  
Rajesh Patidar ◽  
Tomas Vilimas ◽  
...  

3111 Background: Patient-derived xenografts (PDXs) are increasingly being used in translational cancer research for preclinical drug efficacy studies. The National Cancer Institute (NCI) has developed a Patient-Derived Models Repository (NCI PDMR; pdmr.cancer.gov ) of PDXs with clinical annotation, proteomics, and comprehensive genomic datasets to facilitate these studies. Here, we present an integrative genomic, transcriptomic, and proteomic analysis of critical signaling and DNA damage repair pathways in these PDX models, which represent 9 common and multiple rare tumor histologies. Methods: 304 PDX models from 294 patients were established from various solid tumor histologies from patients with primary or metastatic cancer. Whole Exome Sequencing, RNA-Seq and Reverse Phase Protein Array (RPPA) were performed on 2-9 PDXs per model across multiple passages. An integrative workflow was applied on multiple data sets to detect pathway activation. Results: We profiled 10 signaling and 5 DNA repair pathways in the PDMR dataset. We observed that: (i) a large fraction (40%) of PDX models have at least 1 targetable mutation in the RTK/RAS and/or PIK3CA pathways; (ii) 131 models (45%) have putative driver and oncogenic mutations and copy number variants (CNVs) in the WNT, TGFRb , NRF2 and NOTCH pathways. In addition, 17% of PDX models have targetable mutations in DNA damage repair pathways and 20 PDMR models have a DNA mismatch repair defect (MSI-H). We confirmed activation of the signaling pathways in a subset of PDX models by pathway enrichment analysis on gene expression data from RNASeq and phosphoprotein-specific antibody binding data from RPPA. Activation of DNA repair processes was confirmed by enrichment of relevant mutational signatures and loss of heterozygosity in these PDX models. Conclusions: Genomic analysis of NCI PDMR models revealed that a large fraction have clinically relevant somatic alterations in key signaling and DNA damage repair pathways. Further integrative analyses with matched transcriptomic and proteomic profiles confirmed pathway activation in a subset of these models, which may prioritize them for preclinical drug studies.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Alessandra Tessitore ◽  
Germana Cicciarelli ◽  
Filippo Del Vecchio ◽  
Agata Gaggiano ◽  
Daniela Verzella ◽  
...  

Cancer is a multistep process characterized by various and different genetic lesions which cause the transformation of normal cells into tumor cells. To preserve the genomic integrity, eukaryotic cells need a complex DNA damage/repair response network of signaling pathways, involving many proteins, able to induce cell cycle arrest, apoptosis, or DNA repair. Chemotherapy and/or radiation therapy are the most commonly used therapeutic approaches to manage cancer and act mainly through the induction of DNA damage. Impairment in the DNA repair proteins, which physiologically protect cells from persistent DNA injury, can affect the efficacy of cancer therapies. Recently, increasing evidence has suggested that microRNAs take actively part in the regulation of the DNA damage/repair network. MicroRNAs are endogenous short noncoding molecules able to regulate gene expression at the post-transcriptional level. Due to their activity, microRNAs play a role in many fundamental physiological and pathological processes. In this review we report and discuss the role of microRNAs in the DNA damage/repair and cancer.


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