scholarly journals The DREAM complex represses growth in response to DNA damage in Arabidopsis

2021 ◽  
Vol 4 (12) ◽  
pp. e202101141
Author(s):  
Lucas Lang ◽  
Aladár Pettkó-Szandtner ◽  
Hasibe Tunçay Elbaşı ◽  
Hirotomo Takatsuka ◽  
Yuji Nomoto ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Double Mutant ◽  
Growth Arrest ◽  
Suppressor Gene ◽  
Physiological Processes ◽  
Damage Response ◽  
Arabidopsis Homolog ◽  
Close Homolog

The DNA of all organisms is constantly damaged by physiological processes and environmental conditions. Upon persistent damage, plant growth and cell proliferation are reduced. Based on previous findings that RBR1, the only Arabidopsis homolog of the mammalian tumor suppressor gene retinoblastoma, plays a key role in the DNA damage response in plants, we unravel here the network of RBR1 interactors under DNA stress conditions. This led to the identification of homologs of every DREAM component in Arabidopsis, including previously not recognized homologs of LIN52. Interestingly, we also discovered NAC044, a mediator of DNA damage response in plants and close homolog of the major DNA damage regulator SOG1, to directly interact with RBR1 and the DREAM component LIN37B. Consistently, not only mutants in NAC044 but also the double mutant of the two LIN37 homologs and mutants for the DREAM component E2FB showed reduced sensitivities to DNA-damaging conditions. Our work indicates the existence of multiple DREAM complexes that work in conjunction with NAC044 to mediate growth arrest after DNA damage.

Novel SIRT1 Agonists, SRT501 and SRT2183, Induce Expression of DNA Repair Genes and Apoptosis of Ph− Acute Lymphoblastic Leukemia Cells Alone and in Combination with the HDAC Inhibitor LBH589..

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3083-3083
Author(s):  
Anna Scuto ◽  
Mark Kirschbaum ◽  
Jennifer M Cermak ◽  
Peter Atadja ◽  
Richard Jove
Keyword(s):  
Dna Damage ◽  
Acute Lymphoblastic Leukemia ◽  
Histone Deacetylase ◽  
Dna Damage Response ◽  
Histone Deacetylase Inhibitors ◽  
Lymphoblastic Leukemia ◽  
Philadelphia Chromosome ◽  
Growth Arrest ◽  
Mrna Levels ◽  
Damage Response

Abstract Abstract 3083 Poster Board III-20 Histone Deacetylase Inhibitors (HDACi) such as LBH589, which inhibit the zinc containing catalytic domain of HDAC of classes I, II, and IV, demonstrate activity against various malignancies, particularly lymphoid malignancies. SIRT1 is an NAD+ dependent class III histone deacetylase, which deacetylates histones as well as non-histone proteins and is not affected directly by HDACi such as LBH589. It remains controversial whether inhibition of SIRT1 or its activation is more efficacious in anticancer therapy. We have studied the activity of two novel SIRT1 activators, SRT501 and SRT2183, in Philadelphia chromosome negative acute lymphoblastic leukemia (ALL) cell lines. Both pre B (NALM-6, Reh) and T cell (MOLT-4) ALL lines were treated with either SRT501 or SRT2183, as well as in combination with LBH589 and evaluated for biological and gene expression responses. SRT501 induced growth arrest and apoptosis at doses ranging from 10-100 uM, with even the lowest doses inhibiting growth at 72 hours. SRT2183 is much more potent, with growth arrest and apoptosis induced at doses ranging from 1-20 uM. PCR array analysis revealed that SRT2183 treatment leads to increased mRNA levels of pro-apoptosis, growth arrest, and DNA damage response genes. We have previously demonstrated that the activity of LBH589 is mediated in part through upregulation or acetylation of proteins involved in the DNA damage response pathways. Quantitative real-time PCR confirms that the combination of LBH589 with SRT2183 leads to significantly higher expression of GADD45A and GADD45G than either agent alone. The combination of LBH589 plus SRT2183 showed enhanced inhibition of c-Myc protein levels, phosphorylation of H2A.X, and interestingly, increased acetylation of p53 (acetylation of p53 was not seen with SRT2183 alone). In summary, the novel SIRT1 activators SRT501 and SRT2183 show growth inhibitory and pro-apoptotic activity in Ph- ALL alone and enhanced activity in combination with LBH589. Clinical studies of these agents, particularly in combination with HDACi are warranted. Disclosures Kirschbaum: Novartis: Consultancy. Cermak:Sirtris: Employment. Atadja:Novartis: Employment.

scholarly journals PML Colocalizes with and Stabilizes the DNA Damage Response Protein TopBP1

2003 ◽  
Vol 23 (12) ◽  
pp. 4247-4256 ◽  
Author(s):  
Zhi-Xiang Xu ◽  
Anna Timanova-Atanasova ◽  
Rui-Xun Zhao ◽  
Kun-Sang Chang
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Genome Stability ◽  
Growth Regulation ◽  
Suppressor Gene ◽  
Nuclear Body ◽  
Promyelocytic Leukemia ◽  
Multifunctional Protein ◽  
Damage Response

ABSTRACT The PML tumor suppressor gene is consistently disrupted by t(15;17) in patients with acute promyelocytic leukemia. Promyelocytic leukemia protein (PML) is a multifunctional protein that plays essential roles in cell growth regulation, apoptosis, transcriptional regulation, and genome stability. Our study here shows that PML colocalizes and associates in vivo with the DNA damage response protein TopBP1 in response to ionizing radiation (IR). Both PML and TopBP1 colocalized with the IR-induced bromodeoxyuridine single-stranded DNA foci. PML and TopBP1 also colocalized with Rad50, Brca1, ATM, Rad9, and BLM. IR and interferon (IFN) coinduce the expression levels of both TopBP1 and PML. In PML-deficient NB4 cells, TopBP1 was unable to form IR-induced foci. All-trans-retinoic acid induced reorganization of the PML nuclear body (NB) and reappearance of the IR-induced TopBP1 foci. Inhibition of PML expression by siRNA is associated with a significant decreased in TopBP1 expression. Furthermore, PML-deficient cells express a low level of TopBP1, and its expression cannot be induced by IR or IFN. Adenovirus-mediated overexpression of PML in PML−/− mouse embryo fibroblasts substantially increased TopBP1 expression, which colocalized with the PML NBs. These studies demonstrated a mechanism of PML-dependent expression of TopBP1. PML overexpression induced TopBP1 protein but not the mRNA expression. Pulse-chase labeling analysis demonstrated that PML overexpression stabilized the TopBP1 protein, suggesting that PML plays a role in regulating the stability of TopBP1 in response to IR. Together, our findings demonstrate that PML regulates TopBP1 functions by association and stabilization of the protein in response to IR-induced DNA damage.

scholarly journals The dual role of the RETINOBLASTOMA-RELATED protein in the DNA damage response is spatio-temporally coordinated by the interaction with LXCXE-containing proteins.

2021 ◽  
Author(s):  
Jorge Zamora-Zaragoza ◽  
Katinka Klap ◽  
Renze Heidstra ◽  
Wenkun Zhou ◽  
Ben Scheres
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Dna Repair ◽  
Cell Division ◽  
Dna Damage Response ◽  
Growth Arrest ◽  
Focus Formation ◽  
Damage Response ◽  
Nuclear Foci ◽  
Lxcxe Motif

Living organisms face threats to genome integrity caused by environmental challenges or metabolic errors in proliferating cells. To avoid the spread of mutations, cell division is temporarily arrested while repair mechanisms deal with DNA lesions. Afterwards, cells either resume division or respond to unsuccessful repair by withdrawing from the cell cycle and undergoing cell death. How the success rate of DNA repair connects to the execution of cell death remains incompletely known, particularly in plants. Here we provide evidence that the Arabidopsis thaliana RETINOBLASTOMA-RELATED1 (RBR) protein, shown to play structural and transcriptional functions in the DNA damage response (DDR), coordinates these processes in time by successive interactions through its B-pocket sub-domain. Upon DNA damage induction, RBR forms nuclear foci; but the N849F substitution in the B-pocket, which specifically disrupts binding to LXCXE motif-containing proteins, abolishes RBR focus formation and leads to growth arrest. After RBR focus formation, the stress-responsive gene NAC044 arrests cell division. As RBR is released from nuclear foci, it can be bound by the conserved LXCXE motif in NAC044. RBR-mediated cell survival is inhibited by the interaction with NAC044. Disruption of NAC044-RBR interaction impairs the cell death response but is less important for NAC044 mediated growth arrest. Noteworthy, unlike many RBR interactors, NAC044 binds to RBR independent of RBR phosphorylation. Our findings suggest that the availability of the RBR B-pocket to interact with LXCXE-containing proteins couples the structural DNA repair functions and the transcriptional functions of RBR in the cell death program.

scholarly journals Computational correction of off-targeting for CRISPR-Cas9 essentiality screens

2019 ◽  
Author(s):  
Alexendar R. Perez ◽  
Laura Sala ◽  
Richard K. Perez ◽  
Joana A. Vidigal
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Large Scale ◽  
Computational Method ◽  
Seamless Integration ◽  
Guide Rnas ◽  
Cycle Arrest ◽  
Damage Response

Off-target cleavage by Cas9 can confound measurements of cell proliferation/viability in CRISPR assays by eliciting a DNA-damage response that includes cell cycle arrest1-3. This gene-independent toxicity has been documented in large scale assays2-4 and shown to be a source of false-positives when libraries are populated by promiscuous guide RNAs (gRNAs)7. To address this, we developed CSC, a computational method to correct for the effect of specificity on gRNA depletion. We applied CSC to screening data from the Cancer Dependency Map and show that it significantly improves the specificity of CRISPR-Cas9 essentiality screens while preserving known gene essentialities even for genes targeted by highly pro-miscuous guides. We packaged CSC in a Python software to allow its seamless integration into current CRISPR analysis pipelines and improve the sensitivity of essentiality screens for repetitive genomic loci.

scholarly journals Oncogenes induce senescence with incomplete growth arrest and suppress the DNA damage response in immortalized cells

Aging Cell ◽  
2011 ◽  
Vol 10 (6) ◽  
pp. 949-961 ◽  
Author(s):  
Michael Y. Sherman ◽  
Le Meng ◽  
Martha Stampfer ◽  
Vladimir L. Gabai ◽  
Julia A. Yaglom
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Growth Arrest ◽  
Damage Response ◽  
Immortalized Cells

scholarly journals Pseudolaric acid B inhibits neuroglioma cell proliferation through DNA damage response

2017 ◽  
Vol 38 (4) ◽  
pp. 2211-2218 ◽  
Author(s):  
Fengmei Song ◽  
Xiaoyan Yu ◽  
Haipeng Zhang ◽  
Zengyan Wang ◽  
Yue Wang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Pseudolaric Acid B ◽  
Damage Response

scholarly journals The p400/Tip60 ratio is critical for colorectal cancer cell proliferation through DNA damage response pathways

Oncogene ◽  
2009 ◽  
Vol 28 (12) ◽  
pp. 1506-1517 ◽  
Author(s):  
L Mattera ◽  
F Escaffit ◽  
M-J Pillaire ◽  
J Selves ◽  
S Tyteca ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Dna Damage ◽  
Cancer Cell ◽  
Dna Damage Response ◽  
Colorectal Cancer Cell ◽  
Cancer Cell Proliferation ◽  
Damage Response

scholarly journals DNA Damage Response in the Adaptive Arm of the Immune System: Implications for Autoimmunity

2021 ◽  
Vol 22 (11) ◽  
pp. 5842
Author(s):  
Theodora Manolakou ◽  
Panayotis Verginis ◽  
Dimitrios T. Boumpas
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Immune Cells ◽  
Uv Light ◽  
Adaptive Immune ◽  
Physiological Processes ◽  
Adaptive Immune Cells ◽  
Damage Response ◽  
Environmental Agents ◽  
Dna Alterations

In complex environments, cells have developed molecular responses to confront threats against the genome and achieve the maintenance of genomic stability assuring the transfer of undamaged DNA to their progeny. DNA damage response (DDR) mechanisms may be activated upon genotoxic or environmental agents, such as cytotoxic drugs or ultraviolet (UV) light, and during physiological processes requiring DNA transactions, to restore DNA alterations that may cause cellular malfunction and affect viability. In addition to the DDR, multicellular organisms have evolved specialized immune cells to respond and defend against infections. Both adaptive and innate immune cells are subjected to DDR processes, either as a prerequisite to the immune response, or as a result of random endogenous and exogenous insults. Aberrant DDR activities have been extensively studied in the immune cells of the innate arm, but not in adaptive immune cells. Here, we discuss how the aberrant DDR may lead to autoimmunity, with emphasis on the adaptive immune cells and the potential of therapeutic targeting.

scholarly journals Hops/Tmub1 Heterozygous Mouse Shows Haploinsufficiency Effect in Influencing p53-Mediated Apoptosis

2021 ◽  
Vol 22 (13) ◽  
pp. 7186
Author(s):  
Simona Ferracchiato ◽  
Nicola Di-Iacovo ◽  
Damiano Scopetti ◽  
Danilo Piobbico ◽  
Marilena Castelli ◽  
...  
Keyword(s):  
Dna Damage ◽  
Tumor Suppressor ◽  
Dna Damage Response ◽  
Stress Responses ◽  
Mammalian Cells ◽  
P53 Protein ◽  
Suppressor Gene ◽  
Mrna Levels ◽  
Damage Response ◽  
Transcript Profiles

HOPS is a ubiquitin-like protein implicated in many aspects of cellular function including the regulation of mitotic activity, proliferation, and cellular stress responses. In this study, we focused on the complex relationship between HOPS and the tumor suppressor p53, investigating both transcriptional and non-transcriptional p53 responses. Here, we demonstrated that Hops heterozygous mice and mouse embryonic fibroblasts exhibit an impaired DNA-damage response to etoposide-induced double-strand breaks when compared to wild-type genes. Specifically, alterations in HOPS levels caused significant defects in the induction of apoptosis, including a reduction in p53 protein level and percentage of apoptotic cells. We also analyzed the effect of reduced HOPS levels on the DNA-damage response by examining the transcript profiles of p53-dependent genes, showing a suggestive deregulation of the mRNA levels for a number of p53-dependent genes. Taken together, these results show an interesting haploinsufficiency effect mediated by Hops monoallelic deletion, which appears to be enough to destabilize the p53 protein and its functions. Finally, these data indicate a novel role for Hops as a tumor-suppressor gene in DNA damage repair in mammalian cells.

scholarly journals HSATII RNA is induced via a non-canonical ATM-regulated DNA-damage response pathway and facilitates tumor cell proliferation and movement

2020 ◽  
Author(s):  
Maciej T. Nogalski ◽  
Thomas Shenk
Keyword(s):  
Breast Cancer ◽  
Cell Proliferation ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Rna Expression ◽  
Tumor Cell Proliferation ◽  
Dna Damaging Agents ◽  
Damage Response ◽  
Infected Cells ◽  
Dna Damage Response Pathway

ABSTRACTPericentromeric human satellite II (HSATII) repeats are normally silent, but can be actively transcribed in tumor cells, where increased HSATII copy number is associated with a poor prognosis in colon cancer, and in human cytomegalovirus (HCMV)-infected cells, where the RNA facilitates viral replication. Here, we report that HCMV infection or treatment of ARPE-19 diploid epithelial cells with the DNA-damaging agents, etoposide and zeocin, induced HSATII RNA expression, and a kinase-independent function of ATM was required for the induction. Additionally, various breast cancer cell lines growing in adherent, 2-dimensional cell culture expressed HSATII RNA at different levels, and levels were markedly increased when cells were either infected with HCMV or treated with zeocin. High levels of HSATII RNA expression correlated with enhanced migration of breast cancer cells, and knockdown of HSATII RNA reduced cell migration and the rate of cell proliferation. Our investigation links high expression of HSATII RNA to the DNA damage response, centered on a non-canonical function of ATM, and demonstrates a role for the satellite RNA in tumor cell proliferation and movement.SIGNIFICANCEHSATII RNA is associated with cancer progression, immunostimulation and, as we recently reported, it plays an important role in herpesvirus infections. However, the understanding of cellular processes responsible for the expression of HSATII RNA has been limited. Our current investigation identified a non-canonical, ATM kinase-independent DNA-damage response pathway as a common cellular mechanism regulating HSATII RNA induction in virus-infected cells or cells treated with DNA-damaging agents. Additionally, our study provides a link between expression of HSATII RNA and the cellular growth and migration phenotypes of cancer cells, establishing a new paradigm to study the biological consequences of HSATII RNA expression, i.e., treatment of normal diploid and tumor cells with DNA-damaging agents.

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