scholarly journals SIRT7-mediated ATM deacetylation is essential for its deactivation and DNA damage repair

2019 ◽  
Vol 5 (3) ◽  
pp. eaav1118 ◽  
Author(s):  
Ming Tang ◽  
Zhiming Li ◽  
Chaohua Zhang ◽  
Xiaopeng Lu ◽  
Bo Tu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Repair ◽  
Class Iii ◽  
Ataxia Telangiectasia Mutated ◽  
Damage Repair ◽  
Damage Response ◽  
Late Stages

The activation of ataxia-telangiectasia mutated (ATM) upon DNA damage involves a cascade of reactions, including acetylation by TIP60 and autophosphorylation. However, how ATM is progressively deactivated after completing DNA damage repair remains obscure. Here, we report that sirtuin 7 (SIRT7)–mediated deacetylation is essential for dephosphorylation and deactivation of ATM. We show that SIRT7, a class III histone deacetylase, interacts with and deacetylates ATM in vitro and in vivo. In response to DNA damage, SIRT7 is mobilized onto chromatin and deacetylates ATM during the late stages of DNA damage response, when ATM is being gradually deactivated. Deacetylation of ATM by SIRT7 is prerequisite for its dephosphorylation by its phosphatase WIP1. Consequently, depletion of SIRT7 or acetylation-mimic mutation of ATM induces persistent ATM phosphorylation and activation, thus leading to impaired DNA damage repair. Together, our findings reveal a previously unidentified role of SIRT7 in regulating ATM activity and DNA damage repair.

scholarly journals PAICS contributes to gastric carcinogenesis and participates in DNA damage response by interacting with histone deacetylase 1/2

2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Nan Huang ◽  
Chang Xu ◽  
Liang Deng ◽  
Xue Li ◽  
Zhixuan Bian ◽  
...  
Keyword(s):  
Dna Damage ◽  
Histone Deacetylase ◽  
Dna Damage Response ◽  
De Novo ◽  
Dna Damage Repair ◽  
Histone Deacetylase 1 ◽  
Damage Repair ◽  
Damage Response

AbstractPhosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS), an essential enzyme involved in de novo purine biosynthesis, is connected with formation of various tumors. However, the specific biological roles and related mechanisms of PAICS in gastric cancer (GC) remain unclear. In the present study, we identified for the first time that PAICS was significantly upregulated in GC and high expression of PAICS was correlated with poor prognosis of patients with GC. In addition, knockdown of PAICS significantly induced cell apoptosis, and inhibited GC cell growth both in vitro and in vivo. Mechanistic studies first found that PAICS was engaged in DNA damage response, and knockdown of PAICS in GC cell lines induced DNA damage and impaired DNA damage repair efficiency. Further explorations revealed that PAICS interacted with histone deacetylase HDAC1 and HDAC2, and PAICS deficiency decreased the expression of DAD51 and inhibited its recruitment to DNA damage sites by impairing HDAC1/2 deacetylase activity, eventually preventing DNA damage repair. Consistently, PAICS deficiency enhanced the sensitivity of GC cells to DNA damage agent, cisplatin (CDDP), both in vitro and in vivo. Altogether, our findings demonstrate that PAICS plays an oncogenic role in GC, which act as a novel diagnosis and prognostic biomarker for patients with GC.

scholarly journals LINC-PINT impedes DNA repair and enhances radiotherapeutic response by targeting DNA-PKcs in nasopharyngeal cancer

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
You-hong Wang ◽  
Zhen Guo ◽  
Liang An ◽  
Yong Zhou ◽  
Heng Xu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Nasopharyngeal Cancer ◽  
Noncoding Rnas ◽  
Dependent Protein Kinase ◽  
Damage Repair ◽  
Dependent Protein ◽  
Cancer Tissues

AbstractRadioresistance continues to be the leading cause of recurrence and metastasis in nasopharyngeal cancer. Long noncoding RNAs are emerging as regulators of DNA damage and radioresistance. LINC-PINT was originally identified as a tumor suppressor in various cancers. In this study, LINC-PINT was significantly downregulated in nasopharyngeal cancer tissues than in rhinitis tissues, and low LINC-PINT expressions showed poorer prognosis in patients who received radiotherapy. We further identified a functional role of LINC-PINT in inhibiting the malignant phenotypes and sensitizing cancer cells to irradiation in vitro and in vivo. Mechanistically, LINC-PINT was responsive to DNA damage, inhibiting DNA damage repair through ATM/ATR-Chk1/Chk2 signaling pathways. Moreover, LINC-PINT increased radiosensitivity by interacting with DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and negatively regulated the expression and recruitment of DNA-PKcs. Therefore, these findings collectively support the possibility that LINC-PINT serves as an attractive target to overcome radioresistance in NPC.

scholarly journals Dephosphorylation of the C-terminal Tyrosyl Residue of the DNA Damage-related Histone H2A.X Is Mediated by the Protein Phosphatase Eyes Absent

2009 ◽  
Vol 284 (24) ◽  
pp. 16066-16070 ◽  
Author(s):  
Navasona Krishnan ◽  
Dae Gwin Jeong ◽  
Suk-Kyeong Jung ◽  
Seong Eon Ryu ◽  
Andrew Xiao ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Mammalian Cells ◽  
Protein Tyrosine Phosphatases ◽  
Histone H2a ◽  
Eyes Absent ◽  
Damage Repair ◽  
Damage Response

In mammalian cells, the DNA damage-related histone H2A variant H2A.X is characterized by a C-terminal tyrosyl residue, Tyr-142, which is phosphorylated by an atypical kinase, WSTF. The phosphorylation status of Tyr-142 in H2A.X has been shown to be an important regulator of the DNA damage response by controlling the formation of γH2A.X foci, which are platforms for recruiting molecules involved in DNA damage repair and signaling. In this work, we present evidence to support the identification of the Eyes Absent (EYA) phosphatases, protein-tyrosine phosphatases of the haloacid dehalogenase superfamily, as being responsible for dephosphorylating the C-terminal tyrosyl residue of histone H2A.X. We demonstrate that EYA2 and EYA3 displayed specificity for Tyr-142 of H2A.X in assays in vitro. Suppression of eya3 by RNA interference resulted in elevated basal phosphorylation and inhibited DNA damage-induced dephosphorylation of Tyr-142 of H2A.X in vivo. This study provides the first indication of a physiological substrate for the EYA phosphatases and suggests a novel role for these enzymes in regulation of the DNA damage response.

scholarly journals Antitumor Activity of a Novel Tyrosine Kinase Inhibitor AIU2001 Due to Abrogation of the DNA Damage Repair in Non-Small Cell Lung Cancer Cells

2019 ◽  
Vol 20 (19) ◽  
pp. 4728 ◽  
Author(s):  
Hwani Ryu ◽  
Hyun-Kyung Choi ◽  
Hyo Jeong Kim ◽  
Ah-Young Kim ◽  
Jie-Young Song ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Dna Damage ◽  
Tyrosine Kinase ◽  
Small Molecule ◽  
Parp Inhibitor ◽  
Dna Damage Repair ◽  
Class Iii ◽  
Damage Repair ◽  
Repair Genes

Class III receptor tyrosine kinase (RTK) inhibitors targeting mainly FLT3 or c-KIT have not been well studied in lung cancer. To identify a small molecule potentially targeting class III RTK, we synthesized novel small molecule compounds and identified 5-(4-bromophenyl)-N-(naphthalen-1-yl) oxazol-2-amine (AIU2001) as a novel class III RKT inhibitor. In an in vitro kinase profiling assay, AIU2001 inhibited the activities of FLT3, mutated FLT3, FLT4, and c-KIT of class III RTK, and the proliferation of NSCLC cells in vitro and in vivo. AIU2001 induced DNA damage, reactive oxygen species (ROS) generation, and cell cycle arrest in the G2/M phase. Furthermore, AIU2001 suppressed the DNA damage repair genes, resulting in the ‘BRCAness’/‘DNA-PKness’ phenotype. The mRNA expression level of STAT5 was downregulated by AIU2001 treatment and knockdown of STAT5 inhibited the DNA repair genes. Our results show that compared to either drug alone, the combination of AIU2001 with a poly (ADP-ribose) polymerase (PARP) inhibitor olaparib or irradiation showed synergistic efficacy in H1299 and A549 cells. Hence, our findings demonstrate that AIU2001 is a candidate therapeutic agent for NSCLC and combination therapies with AIU2001 and a PARP inhibitor or radiotherapy may be used to increase the therapeutic efficacy of AIU2001 due to inhibition of DNA damage repair.

Effect of inhibition of receptor tyrosine kinase AXL by a selective small molecular inhibitor R428 (BGB321) on DNA damage repair response in ovarian cancer cells.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e15640-e15640
Author(s):  
Ruby Yun-Ju Huang ◽  
Xun Hui Yeo ◽  
Wai Leong Tam
Keyword(s):  
Dna Damage ◽  
Tyrosine Kinase ◽  
Cell Lines ◽  
Dna Damage Response ◽  
Receptor Tyrosine Kinase ◽  
Dna Damage Repair ◽  
Damage Repair ◽  
Damage Response ◽  
Dna Damage Responses

e15640 Background: AXL is a receptor tyrosine kinase that is often overexpressed in many cancers. It contributes to tumor progression, metastasis and drug resistance through activating downstream signaling cascades, making it an emerging therapeutic target. The first-in-class AXL inhibitor R428 (BGB321) was approved by the FDA for the treatment of relapsed or refractory acute myeloid leukemia. R428 (BGB321) was also reported to show selective sensitivity towards ovarian cancers (OC) with a Mesenchymal (Mes) molecular subtype. Recently, a novel role of AXL in the regulation of DNA damage responses has been described. In this study, we explored further the role of AXL in mediating DNA damage responses by using OC as a disease model. Methods: OC cell lines were treated with R428. Accumulation of γH2AX positive foci was assessed for DNA damage response. Western blotting for γH2AX, ATM and ATR levels were performed. Dose response curves of ATR inhibitors were generated by treating OC cells with the fixed dose of R428 (IC20 concentration of each cell line). Results: AXL inhibition by using R428 resulted in the increase of DNA damage foci in Mes OC cells SKOV3 and HeyA8. This occurred concurrently with the up-regulation of classic DNA damage response signaling molecules such as γH2AX, ATM and ATR. The IC50 of the ATR inhibitor significantly decreased for 2-3 folds in all OC cell lines tested. AXL inhibitor R428 sensitized both BRCA-mutated and non-BRCA-mutated OC cells to a potent and highly selective ATR inhibitor. Conclusions: Our results showed that AXL inhibition rendered cells more sensitive to the inhibition of ATR, a crucial mediator for replication stress, paving ways to the rationale for potential combinatory use of AXL and DNA damage repair inhibitors.

Molecular landscape of gastric cancer (GC) harboring mutations of histone methyltransferases.

2020 ◽  
Vol 38 (4_suppl) ◽  
pp. 418-418
Author(s):  
Jingyuan Wang ◽  
Joanne Xiu ◽  
Yasmine Baca ◽  
Richard M. Goldberg ◽  
Philip Agop Philip ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cancer Progression ◽  
Dna Damage Repair ◽  
Treatment Strategies ◽  
Gene Mutations ◽  
Mutation Rates ◽  
Aberrant Expression ◽  
Damage Repair

418 Background: Alteration of histone modifications participating in transcription and genomic instability, has been recognized as an important role in tumorigenesis. Aberrant expression of histone-lysine N-methyltransferase 2 ( KMT2) family, which methylate histone H3 on lysine 4, is significantly correlated with poor survival in GC. Understanding how gene mutations of KMT2 family interact to affect cancer progression could lead to new treatment strategies. Methods: A total of 1,245 GC were analyzed using next-generation sequencing (NGS) and immunohistochemistry (IHC; Caris Life Sciences, Phoenix, AZ). Tumor mutational burden (TMB) was calculated based on somatic nonsynonymous mutations, and MSI status was evaluated by a combination of IHC, fragment analysis and NGS. PD-L1 status was analyzed by IHC (SP142). Gene fusions were detected by Archer (N = 59) or whole-transcriptome sequencing (N = 129). Results: The overall mutation rate of genes in KMT2 family was 10.6% ( KMT2A: 1.7 %, KMT2C: 4.7%, KMT2D: 7.1%). Overall, the mutation rates were significantly higher in KMT2-mutated (MT) GC than KMT2-wild type (WT) GC, except for TP53 (43% vs 63%, p < .0001). Interestingly, among the genes with significant higher mutation rates in KMT2-MT GC, 28% (21/76) of them were related to DNA damage repair (including BRCA1/ 2, RAD50) and 33% (25/76) of them were related to chromatin remodeling (including ARID1A/ 2, SMARCA4). Overexpression of HER2, amplifications of KRAS, CDK6 and HER2 were significant lower, while PCM1 and BCL3 amplifications were significant higher in KMT2-MT, compared to KMT2-WT GC ( p < .05). Significantly higher prevalence of TMB-high ( > 17mut/MB) (49% vs 3%), MSI-H (53% vs 2%), and PD-L1 overexpression (20% vs 7%) were present in KMT2-MT GC, compared to KMT2-WT GC ( p < .001). The rates of fusions involving ARHGAP26 (19% vs 3%, p < .01)and RELA (29% vs 0%, p < .0001) were significantly higher in KMT2-MT than those in KMT2-WT GC. Conclusions: This is the largest study to investigate the distinct genomic landscape between KMT2-MT and WT GC. Our data indicates that KMT2-MT GC patients could potentially benefit from agents targeting DNA damage repair and immunotherapy, which warrants further in-vitro and in-vivo investigation.

Overcoming miR-106a induced radioresistance in prostate cancer: Targeting senescence with KU-55933.

2018 ◽  
Vol 36 (6_suppl) ◽  
pp. 77-77
Author(s):  
Christianne Hoey ◽  
Jessica Ray ◽  
Xiaoyong Huang ◽  
Jouhyun Jeon ◽  
Paul Christopher Boutros ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Dna Damage ◽  
Dna Damage Repair ◽  
Clonogenic Survival ◽  
High Grade ◽  
Prostate Tumors ◽  
Normal Prostate ◽  
Damage Repair

77 Background: Prostate cancer is a leading cause of cancer related death in men worldwide, with recurrence being a major clinical problem after radiotherapy. There is an unmet need to better characterize radioresistant tumors and identify biomarkers to improve patient outcomes. Methods: We identified that miR-106a was overexpressed in radiation resistant cell lines compared to parental cells. We analyzed The Cancer Genome Atlas dataset to assess miR-106a expression in normal prostate, and low- to high-grade prostate tumors. To assess the functional role of miR-106a, we performed in vitro and in vivo assays for radiation response, including clonogenic survival, proliferation, senescence, and tumor xenograft growth after radiation. We performed gene array and pathway analyses to identify downstream effectors of miR-106a. Results: MiR-106a expression was significantly higher in prostate tumors with Gleason score > 7 compared to Gleason ≤ 7, suggesting miR-106a is involved in high grade disease. MiR-106a overexpression confers radioresistance in vitro and in vivo, by targeting LITAF. We now extend miR-106a’s effects to upregulation of ATM at the promoter level, thereby increasing ATM transcript and protein in the cell. Unexpectedly, we found that miR-106a’s mechanism of radioresistance through ATM upregulation does not alter DNA damage repair. ATM upregulation affects clonogenic survival through reduced senescence. KU-55933, a specific ATM kinase inhibitor, resensitizes miR-106a overexpressing cells to radiation by inducing senescence, a predominant mode of cell death in prostate cancer. Conclusions: Our research challenges the current paradigm of ATM and DNA damage repair by outlining another mechanism of radioresistance through alteration of senescence. Our findings suggest that miR-106a may be a promising biomarker for high-grade disease and radioresistant prostate cancer. In addition, we have identified a therapeutic intervention for miR-106a induced radioresistance. Improvements in bioavailability of KU-55933 may lead to its clinical use in combination with radiation therapy to radiosensitize miR-106a induced radioresistant prostate cancer.

scholarly journals Semisynthesis of site-specifically succinylated histone reveals that succinylation regulates nucleosome unwrapping rate and DNA accessibility

2020 ◽  
Vol 48 (17) ◽  
pp. 9538-9549
Author(s):  
Yihang Jing ◽  
Dongbo Ding ◽  
Gaofei Tian ◽  
Ka Chun Jonathan Kwan ◽  
Zheng Liu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Posttranslational Modifications ◽  
Dna Damage Repair ◽  
Histone H4 ◽  
Chromatin Dynamics ◽  
Nucleosome Dynamics ◽  
Nucleosomal Dna ◽  
Damage Repair

Abstract Posttranslational modifications (PTMs) of histones represent a crucial regulatory mechanism of nucleosome and chromatin dynamics in various of DNA-based cellular processes, such as replication, transcription and DNA damage repair. Lysine succinylation (Ksucc) is a newly identified histone PTM, but its regulation and function in chromatin remain poorly understood. Here, we utilized an expressed protein ligation (EPL) strategy to synthesize histone H4 with site-specific succinylation at K77 residue (H4K77succ), an evolutionarily conserved succinylation site at the nucleosomal DNA-histone interface. We then assembled mononucleosomes with the semisynthetic H4K77succ in vitro. We demonstrated that this succinylation impacts nucleosome dynamics and promotes DNA unwrapping from the histone surface, which allows proteins such as transcription factors to rapidly access buried regions of the nucleosomal DNA. In budding yeast, a lysine-to-glutamic acid mutation, which mimics Ksucc, at the H4K77 site reduced nucleosome stability and led to defects in DNA damage repair and telomere silencing in vivo. Our findings revealed this uncharacterized histone modification has important roles in nucleosome and chromatin dynamics.

scholarly journals Mitotic Errors Promote Genomic Instability and Leukemia in a Novel Mouse Model of Fanconi Anemia

2021 ◽  
Vol 11 ◽  
Author(s):  
Donna M. Edwards ◽  
Dana K. Mitchell ◽  
Zahi Abdul-Sater ◽  
Ka-Kui Chan ◽  
Zejin Sun ◽  
...  
Keyword(s):  
Dna Damage ◽  
Genomic Instability ◽  
Fanconi Anemia ◽  
Spindle Assembly Checkpoint ◽  
Dna Damage Repair ◽  
Spindle Assembly ◽  
Dependent Manner ◽  
Damage Repair

Fanconi anemia (FA) is a disease of genomic instability and cancer. In addition to DNA damage repair, FA pathway proteins are now known to be critical for maintaining faithful chromosome segregation during mitosis. While impaired DNA damage repair has been studied extensively in FA-associated carcinogenesis in vivo, the oncogenic contribution of mitotic abnormalities secondary to FA pathway deficiency remains incompletely understood. To examine the role of mitotic dysregulation in FA pathway deficient malignancies, we genetically exacerbated the baseline mitotic defect in Fancc-/- mice by introducing heterozygosity of the key spindle assembly checkpoint regulator Mad2. Fancc-/-;Mad2+/- mice were viable, but died from acute myeloid leukemia (AML), thus recapitulating the high risk of myeloid malignancies in FA patients better than Fancc-/-mice. We utilized hematopoietic stem cell transplantation to propagate Fancc-/-; Mad2+/- AML in irradiated healthy mice to model FANCC-deficient AMLs arising in the non-FA population. Compared to cells from Fancc-/- mice, those from Fancc-/-;Mad2+/- mice demonstrated an increase in mitotic errors but equivalent DNA cross-linker hypersensitivity, indicating that the cancer phenotype of Fancc-/-;Mad2+/- mice results from error-prone cell division and not exacerbation of the DNA damage repair defect. We found that FANCC enhances targeting of endogenous MAD2 to prometaphase kinetochores, suggesting a mechanism for how FANCC-dependent regulation of the spindle assembly checkpoint prevents chromosome mis-segregation. Whole-exome sequencing revealed similarities between human FA-associated myelodysplastic syndrome (MDS)/AML and the AML that developed in Fancc-/-; Mad2+/- mice. Together, these data illuminate the role of mitotic dysregulation in FA-pathway deficient malignancies in vivo, show how FANCC adjusts the spindle assembly checkpoint rheostat by regulating MAD2 kinetochore targeting in cell cycle-dependent manner, and establish two new mouse models for preclinical studies of AML.

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