scholarly journals DNA Damage Response is Prominent in Ovarian High-Grade Serous Carcinomas, Especially Those with Rsf-1 (HBXAP) Overexpression

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Malti Kshirsagar ◽  
Wei Jiang ◽  
Ie-Ming Shih
Keyword(s):  
Dna Damage ◽  
Chromatin Remodeling ◽  
Dna Damage Response ◽  
Surrogate Marker ◽  
Serous Carcinoma ◽  
Low Grade ◽  
High Grade ◽  
Significant Difference ◽  
Damage Response ◽  
Microenvironmental Stress

DNA damage commonly occurs in cancer cells as a result of endogenous and tumor microenvironmental stress. In this study, we applied immunohistochemistry to study the expression of phosphorylated Chk2 (pChk2), a surrogate marker of the DNA damage response, in high grade and low grade of ovarian serous carcinoma. A phospho-specific antibody specific for threonine 68 of Chk2 was used for immunohistochemistry on a total of 292 ovarian carcinoma tissues including 250 high-grade and 42 low-grade serous carcinomas. Immunostaining intensity was correlated with clinicopathological features. We found that there was a significant correlation between pChk2 immunostaining intensity and percentage of pChk2 positive cells in tumors and demonstrated that high-grade serous carcinomas expressed an elevated level of pChk2 as compared to low-grade serous carcinomas. Normal ovarian, fallopian tube, ovarian cyst, and serous borderline tumors did not show detectable pChk2 immunoreactivity. There was no significant difference in pChk2 immunoreactivity between primary and recurrent high-grade serous carcinomas. In high-grade serous carcinomas, a significant correlation (P<0.0001) in expression level (both in intensity and percentage) was found between pChk2 and Rsf-1 (HBXAP), a gene involved in chromatin remodeling that is amplified in high-grade serous carcinoma. Our results suggest that the DNA damage response is common in high-grade ovarian serous carcinomas, especially those with Rsf-1 overexpression, suggesting that Rsf-1 may be associated with DNA damage response in high-grade serous carcinomas.

scholarly journals Targeting RNA Polymerase I transcription synergises with TOP1 inhibition in potentiating the DNA damage response in high-grade serous ovarian cancer

2019 ◽  
Author(s):  
Shunfei Yan ◽  
Piyush B. Madhamshettiwar ◽  
Kaylene J. Simpson ◽  
Sarah Ellis ◽  
Jian Kang ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Dna Damage ◽  
Rna Polymerase ◽  
Dna Damage Response ◽  
Parp Inhibitor ◽  
Rna Polymerase I ◽  
Serous Carcinoma ◽  
High Grade ◽  
Damage Response ◽  
Polymerase I

AbstractLimited effective therapeutic options are available for patients with recurrent high-grade serous carcinoma (HGSC), the most common histological subtype accounting for the majority of ovarian cancer deaths. We have shown efficacy in poly-ADP ribose polymerase (PARP) inhibitor-resistant HGSC for the RNA Polymerase I (Pol I) transcription inhibitor CX-5461 through its ability to activate a nucleolar-associated DNA damage response (DDR). Here, we screen the protein-coding genome to identify potential targets whose inhibition enhances the efficacy of CX-5461. We identify a network of cooperating inhibitory interactions, including components of homologous recombination (HR) DNA repair and DNA topoisomerase 1 (TOP1). We highlight that CX-5461 combined with topotecan, a TOP1 inhibitor used as salvage therapy in HGSC, induces robust cell cycle arrest and cell death in a panel of HR-proficient HGSC cell lines. The combination potentiates a nucleolar-associated DDR via recruitment of phosphorylated replication protein A (RPA) and ataxia telangiectasia and Rad3 related protein (ATR). CX-5461 plus low-dose topotecan cooperate to potently inhibit xenograft tumour growth, indicating the potential for this strategy to improve salvage therapeutic regimens to treat HGSC.

scholarly journals Schizosaccharomyces pombe KAT5 contributes to resection and repair of a DNA double strand break

Genetics ◽  
2021 ◽  
Author(s):  
Tingting Li ◽  
Ruben C Petreaca ◽  
Susan L Forsburg
Keyword(s):  
Dna Damage ◽  
Homologous Recombination ◽  
Chromatin Remodeling ◽  
Dna Damage Response ◽  
Histone Acetyltransferase ◽  
Strand Break ◽  
Double Strand Break ◽  
Dna Damage Checkpoint ◽  
Dna Double Strand Break ◽  
Damage Response

Abstract Chromatin remodeling is essential for effective repair of a DNA double strand break. KAT5 (S. pombe Mst1, human TIP60) is a MYST family histone acetyltransferase conserved from yeast to humans that coordinates various DNA damage response activities at a DNA double strand break (DSB), including histone remodeling and activation of the DNA damage checkpoint. In S. pombe, mutations in mst1+ causes sensitivity to DNA damaging drugs. Here we show that Mst1 is recruited to DSBs. Mutation of mst1+ disrupts recruitment of repair proteins and delays resection. These defects are partially rescued by deletion of pku70, which has been previously shown to antagonize repair by homologous recombination. These phenotypes of mst1 are similar to pht1-4KR, a non-acetylatable form of histone variant H2A.Z, which has been proposed to affect resection. Our data suggest that Mst1 functions to direct repair of DSBs towards homologous recombination pathways by modulating resection at the double strand break.

scholarly journals Dual HDAC and PI3K Inhibition Abrogates NFκB- and FOXM1-Mediated DNA Damage Response to Radiosensitize Pediatric High-Grade Gliomas

2018 ◽  
Vol 78 (14) ◽  
pp. 4007-4021 ◽  
Author(s):  
Sharmistha Pal ◽  
David Kozono ◽  
Xiaodong Yang ◽  
Wojciech Fendler ◽  
Whitney Fitts ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
High Grade ◽  
Pi3k Inhibition ◽  
Damage Response ◽  
High Grade Gliomas

scholarly journals MORC2 regulates DNA damage response through a PARP1-dependent pathway

2019 ◽  
Vol 47 (16) ◽  
pp. 8502-8520 ◽  
Author(s):  
Lin Zhang ◽  
Da-Qiang Li
Keyword(s):  
Dna Damage ◽  
Zinc Finger ◽  
Chromatin Remodeling ◽  
Dna Damage Response ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Genotoxic Stress ◽  
Underlying Mechanism ◽  
Dna Lesions ◽  
Damage Response

Abstract Microrchidia family CW-type zinc finger 2 (MORC2) is a newly identified chromatin remodeling enzyme with an emerging role in DNA damage response (DDR), but the underlying mechanism remains largely unknown. Here, we show that poly(ADP-ribose) polymerase 1 (PARP1), a key chromatin-associated enzyme responsible for the synthesis of poly(ADP-ribose) (PAR) polymers in mammalian cells, interacts with and PARylates MORC2 at two residues within its conserved CW-type zinc finger domain. Following DNA damage, PARP1 recruits MORC2 to DNA damage sites and catalyzes MORC2 PARylation, which stimulates its ATPase and chromatin remodeling activities. Mutation of PARylation residues in MORC2 results in reduced cell survival after DNA damage. MORC2, in turn, stabilizes PARP1 through enhancing acetyltransferase NAT10-mediated acetylation of PARP1 at lysine 949, which blocks its ubiquitination at the same residue and subsequent degradation by E3 ubiquitin ligase CHFR. Consequently, depletion of MORC2 or expression of an acetylation-defective PARP1 mutant impairs DNA damage-induced PAR production and PAR-dependent recruitment of DNA repair proteins to DNA lesions, leading to enhanced sensitivity to genotoxic stress. Collectively, these findings uncover a previously unrecognized mechanistic link between MORC2 and PARP1 in the regulation of cellular response to DNA damage.

Should All Cases of High-Grade Serous Ovarian, Tubal, and Primary Peritoneal Carcinomas Be Reclassified as Tubo-Ovarian Serous Carcinoma?

2015 ◽  
Vol 25 (7) ◽  
pp. 1201-1207 ◽  
Author(s):  
Esther Louise Moss ◽  
Tim Evans ◽  
Philippa Pearmain ◽  
Sarah Askew ◽  
Kavita Singh ◽  
...  
Keyword(s):  
Overall Survival ◽  
Clear Cell ◽  
Stage Iii ◽  
Serous Carcinoma ◽  
Low Grade ◽  
Type I ◽  
High Grade ◽  
Type Ii ◽  
Ovarian Serous Carcinoma ◽  
Significant Difference

IntroductionThe dualistic theory of ovarian carcinogenesis proposes that epithelial “ovarian” cancer is not one entity with several histological subtypes but a collection of different diseases arising from cells of different origin, some of which may not originate in the ovarian surface epithelium.MethodsAll cases referred to the Pan-Birmingham Gynaecological Cancer Centre with an ovarian, tubal, or primary peritoneal cancer between April 2006 and April 2012 were identified from the West Midlands Cancer Registry. Tumors were classified into type I (low-grade endometrioid, clear cell, mucinous, and low-grade serous) and type II (high-grade serous, high-grade endometrioid, carcinosarcoma, and undifferentiated) cancers.ResultsOvarian (83.5%), tubal (4.3%), or primary peritoneal carcinoma (12.2%) were diagnosed in a total of 583 woman. The ovarian tumors were type I in 134 cases (27.5%), type II in 325 cases (66.7%), and contained elements of both type I and type II tumors in 28 cases (5.7%). Most tubal and primary peritoneal cases, however, were type II tumors: 24 (96.0%) and 64 (90.1%), respectively. Only 16 (5.8%) of the ovarian high-grade serous carcinomas were stage I at diagnosis, whereas 240 (86.6%) were stage III+. Overall survival varied between the subtypes when matched for stage. Stage III low-grade serous and high-grade serous carcinomas had a significantly better survival compared to clear cell and mucinous cases,P= 0.0134. There was no significant difference in overall survival between the high-grade serous ovarian, tubal, or peritoneal carcinomas when matched for stage (stage III,P= 0.3758; stage IV,P= 0.4820).ConclusionsType II tumors are more common than type I and account for most tubal and peritoneal cancers. High-grade serous carcinomas, whether classified as ovarian/tubal/peritoneal, seem to behave as one disease entity with no significant difference in survival outcomes, therefore supporting the proposition of a separate classification of “tubo-ovarian serous carcinoma”.

scholarly journals Involvement of Global Genome Repair, Transcription Coupled Repair, and Chromatin Remodeling in UV DNA Damage Response Changes during Development

PLoS Genetics ◽  
2010 ◽  
Vol 6 (5) ◽  
pp. e1000941 ◽  
Author(s):  
Hannes Lans ◽  
Jurgen A. Marteijn ◽  
Björn Schumacher ◽  
Jan H. J. Hoeijmakers ◽  
Gert Jansen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Chromatin Remodeling ◽  
Dna Damage Response ◽  
Damage Response ◽  
Global Genome Repair ◽  
Transcription Coupled Repair ◽  
Genome Repair

scholarly journals MORC2 Signaling Integrates Phosphorylation-Dependent, ATPase-Coupled Chromatin Remodeling during the DNA Damage Response

Cell Reports ◽  
2012 ◽  
Vol 2 (6) ◽  
pp. 1657-1669 ◽  
Author(s):  
Da-Qiang Li ◽  
Sujit S. Nair ◽  
Kazufumi Ohshiro ◽  
Anupam Kumar ◽  
Vasudha S. Nair ◽  
...  
Keyword(s):  
Dna Damage ◽  
Chromatin Remodeling ◽  
Dna Damage Response ◽  
Dependent Atpase ◽  
Damage Response

scholarly journals Inhibition of RNA Polymerase I Transcription Activates Targeted DNA Damage Response and Enhances the Efficacy of PARP Inhibitors in High-Grade Serous Ovarian Cancer

2019 ◽  
Author(s):  
Elaine Sanij ◽  
Katherine M. Hannan ◽  
Shunfei Yan ◽  
Jiachen Xuan ◽  
Jessica E. Ahern ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Parp Inhibitors ◽  
Rna Polymerase I ◽  
High Grade ◽  
Replication Forks ◽  
Serous Ovarian Cancer ◽  
Damage Response ◽  
Polymerase I

AbstractHigh-grade serous ovarian cancer (HGSOC) accounts for the majority of ovarian cancer and has a dismal prognosis. PARP inhibitors (PARPi) have revolutionized disease management of patients with homologous recombination (HR) DNA repair-deficient HGSOC. However, acquired resistance to PARPi by complex mechanisms including HR restoration and stabilisation of replication forks is a major challenge in the clinic. Here, we demonstrate CX-5461, an inhibitor of RNA polymerase I transcription of ribosomal RNA genes (rDNA), induces replication stress at rDNA leading to activation of DNA damage response and DNA damage involving MRE11-dependent degradation of replication forks. CX-5461 cooperates with PARPi in exacerbating DNA damage and enhances synthetic lethal interactions of PARPi with HR deficiency in HGSOC-patient-derived xenograft (PDX)in vivo. We demonstrate CX-5461 has a different sensitivity spectrum to PARPi and destabilises replication forks irrespective of HR pathway status, overcoming two well-known mechanisms of resistance to PARPi. Importantly, CX-5461 exhibits single agent efficacy in PARPi-resistant HGSOC-PDX. Further, we identify CX-5461-sensitivity gene expression signatures in primary and relapsed HGSOC. Therefore, CX-5461 is a promising therapy alone and in combination therapy with PARPi in HR-deficient HGSOC. CX-5461 is also an exciting treatment option for patients with relapsed HGSOC tumors that have poor clinical outcome.

scholarly journals The RNA polymerase I transcription inhibitor CX-5461 cooperates with topoisomerase 1 inhibition by enhancing the DNA damage response in homologous recombination-proficient high-grade serous ovarian cancer

2020 ◽  
Author(s):  
Shunfei Yan ◽  
Jiachen Xuan ◽  
Natalie Brajanovski ◽  
Madeleine R. C. Tancock ◽  
Piyush B. Madhamshettiwar ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Dna Damage ◽  
Homologous Recombination ◽  
Dna Damage Response ◽  
Cell Cycle Checkpoint ◽  
Common Mechanism ◽  
High Grade ◽  
M Cell ◽  
Topoisomerase 1 ◽  
Damage Response

Abstract Background Intrinsic and acquired drug resistance represent fundamental barriers to the cure of high-grade serous ovarian carcinoma (HGSC), the most common histological subtype accounting for the majority of ovarian cancer deaths. Defects in homologous recombination (HR) DNA repair are key determinants of sensitivity to chemotherapy and poly-ADP ribose polymerase inhibitors. Restoration of HR is a common mechanism of acquired resistance that results in patient mortality, highlighting the need to identify new therapies targeting HR-proficient disease. We have shown promise for CX-5461, a cancer therapeutic in early phase clinical trials, in treating HR-deficient HGSC. Methods Herein, we screen the whole protein-coding genome to identify potential targets whose depletion cooperates with CX-5461 in HR-proficient HGSC. Results We demonstrate robust proliferation inhibition in cells depleted of DNA topoisomerase 1 (TOP1). Combining the clinically used TOP1 inhibitor topotecan with CX-5461 potentiates a G2/M cell cycle checkpoint arrest in multiple HR-proficient HGSC cell lines. The combination enhances a nucleolar DNA damage response and global replication stress without increasing DNA strand breakage, significantly reducing clonogenic survival and tumour growth in vivo. Conclusions Our findings highlight the possibility of exploiting TOP1 inhibition to be combined with CX-5461 as a non-genotoxic approach in targeting HR-proficient HGSC.

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