BCR/ABL Expression Increases the Formation of Chromosomal Translocations after DNA Damage.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 713-713 ◽  
Author(s):  
Jamil Dierov ◽  
Hesed Padilla-Nash ◽  
Thomas Ried ◽  
Martin Carroll
Keyword(s):  
Dna Damage ◽  
Genomic Instability ◽  
Cellular Response ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Annexin V ◽  
Genotoxic Stress ◽  
Protein Product ◽  
Chromosomal Translocations ◽  
Dna Double Strand Breaks

Abstract BCR/ABL is the protein product of the t(9;22) translocation and is the cause of the hyperproliferation associated with chronic phase chronic myeloid leukemia (CML). However, whether BCR/ABL induces genomic instability leading to blast crisis is controversial. We have previously demonstrated that BCR/ABL translocates to the nucleus after genotoxic damage and associates with the DNA damage sensor, ataxia telangiectasia and rad 3 related (ATR) protein, disrupting the sensing and repair of DNA double strand breaks. Here, we have asked if BCR/ABL expression leads to permanent changes in the DNA after genotoxic stress. For these experiments we have studied the hematopoietic cell line, Ba/F3pTetOn p210, which expresses p210 BCR/ABL after incubation in doxycycline. Cells were incubated in low doses of etoposide for two hours and then allowed to recover for 48 hours in the absence of further DNA damage. Induction of apoptosis in these conditions was consistently less than 5% as demonstrated by annexin V staining of cells. Cells were examined for alterations in the chromosomes using Giemsa banding and spectral karyotyping (SKY). Cells growing in IL3 showed low levels of DNA damage with a few broken chromosomes present in metaphase spreads and an average of 0.5 new chromosomal translocations per cell as revealed by SKY analysis. In contrast, when cells expressing BCR/ABL were treated with the same conditions, a marked number of genetic abnormalities were seen. 75% of cells showed abnormal chromosome forms with ring chromosomes, triradial forms and other abnormalitites. Analysis of BCR/ABL expressing cells by SKY analysis showed frequent abnormalities, averaging at least 6 new translocations per cell. Several cells had greater than 10 translocations present including multiple complex translocations involving more than two chromosomes. The majority of abnormalities consisted of unbalanced translocations. This data demonstrates that BCR/ABL alters the cellular response to DNA damage leading to an increase in chromosomal translocations in cells expressing the oncogene and suggests that BCR/ABL itself is directly responsible for the genomic instability leading to CML blast crisis.

CML Progenitor Cells Have Chromsomal Instability and Display Increased DNA Damage at DNA Fragile Sites.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1989-1989 ◽  
Author(s):  
Jamil K. Dierov ◽  
David W. Schoppy ◽  
Martin Carroll
Keyword(s):  
Dna Damage ◽  
Progenitor Cells ◽  
Chromosomal Instability ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Fragile Sites ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Cd34 Cells

Abstract Chronic myelogeneous leukemia (CML) is a two stage disease which progresses to blast crisis over a period of 3–5 years in untreated patients. The BCR/ABL oncogene induces the hyperproliferation associated with chronic phase CML but whether BCR/ABL induces chromosomal instability leading to blast crisis has been controversial. We have previously demonstrated that BCR/ABL delays the repair of DNA double strand breaks and increases chromosomal instability in a murine cell line. Furthermore, we have demonstrated in cell lines that BCR/ABL disrupts the function of the DNA damage sensing protein, ataxia telangiectasia and rad 3 related (ATR). One of the functions of ATR is to maintain the stability of DNA fragile sites, late replicating sites in the chromosome that are frequently involved in translocations. To determine if BCR/ABL affects the stability of DNA fragile sites in Ba/F3 cells that do or do not express BCR/ABL, cells were incubated in low dose aphidicolin for 24 hours to induce fragile site breakage. BCR/ABL expressing cells, but not control cells, demonstrated fragile site damage consistent with a disruption of ATR function in BCR/ABL expressing cells. In order to determine if primary patient cells display a genomic instability phenotype, we have analyzed the response to DNA damage in CD34+ cells from normal volunteers and from CML patients seen at the University of Pennsylvania Cancer Center. We first examined the DNA repair response by treating cells for two hours with etoposide. Both normal cells and CML progenitor cells demonstrate DNA double strand breaks as measured by the comet assay, a quantitative assay for DNA double strand breaks. However, in Ph+ cells from the patient sample there was a delay in the repair of DNA double strand breaks as indicated by a significant increase in the olive tail moment at 2 hours and 24 hours after treatment with etoposide. In addition, we analyzed the effect of a two hour exposure to etoposide on chromosome stability as measured by spectral karyotyping (SKY). Normal CD34+ cells and CD34+ cells from patients were treated with etoposide and then allowed to recover for 48 hours before analysis of metaphase spreads. Normal cells demonstrated no spontaneous DNA damage and, after etoposide treatment and repair, demonstrated only modest levels of DNA damage (2 translocations and 5 numerical alterations per 14 metaphases analyzed). In contrast, Ph+ cells demonstrated spontaneous DNA damage in these cell conditions. Furthermore, after etoposide treatment Ph+ cells demonstrated high levels of DNA damage with 9 translocations and 12 numerical alterations in 13 metaphases. These results suggest that Ph+ progenitor cells from patients with CML demonstrate chromosomal instability and suggest a mechanism for progression from CML chronic phase to blast crisis. Full analysis of additional patient samples will be presented. Taken together, we propose that BCR/ABL disrupts ATR function in cell lines and primary cells leading to an increase in chromosomal instability that leads to CML blast crisis.

scholarly journals Human papillomavirus E7 oncoprotein targets RNF168 to hijack the host DNA damage response

2019 ◽  
Vol 116 (39) ◽  
pp. 19552-19562 ◽  
Author(s):  
Justine Sitz ◽  
Sophie Anne Blanchet ◽  
Steven F. Gameiro ◽  
Elise Biquand ◽  
Tia M. Morgan ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Dna Damage ◽  
Cancer Cells ◽  
Genomic Instability ◽  
E3 Ligase ◽  
Human Papillomaviruses ◽  
Double Strand Breaks ◽  
Nuclear Bodies ◽  
Dna Double Strand Breaks ◽  
Strand Breaks

High-risk human papillomaviruses (HR-HPVs) promote cervical cancer as well as a subset of anogenital and head and neck cancers. Due to their limited coding capacity, HPVs hijack the host cell’s DNA replication and repair machineries to replicate their own genomes. How this host–pathogen interaction contributes to genomic instability is unknown. Here, we report that HPV-infected cancer cells express high levels of RNF168, an E3 ubiquitin ligase that is critical for proper DNA repair following DNA double-strand breaks, and accumulate high numbers of 53BP1 nuclear bodies, a marker of genomic instability induced by replication stress. We describe a mechanism by which HPV E7 subverts the function of RNF168 at DNA double-strand breaks, providing a rationale for increased homology-directed recombination in E6/E7-expressing cervical cancer cells. By targeting a new regulatory domain of RNF168, E7 binds directly to the E3 ligase without affecting its enzymatic activity. As RNF168 knockdown impairs viral genome amplification in differentiated keratinocytes, we propose that E7 hijacks the E3 ligase to promote the viral replicative cycle. This study reveals a mechanism by which tumor viruses reshape the cellular response to DNA damage by manipulating RNF168-dependent ubiquitin signaling. Importantly, our findings reveal a pathway by which HPV may promote the genomic instability that drives oncogenesis.

scholarly journals SETBP1 accumulation induces P53 inhibition and genotoxic stress in neural progenitors underlying neurodegeneration in Schinzel-Giedion syndrome

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Federica Banfi ◽  
Alicia Rubio ◽  
Mattia Zaghi ◽  
Luca Massimino ◽  
Giulia Fagnocchi ◽  
...  
Keyword(s):  
Dna Damage ◽  
Neuronal Death ◽  
Neuronal Loss ◽  
Genotoxic Stress ◽  
Protein Product ◽  
Neural Progenitors ◽  
Cell Identity ◽  
Neurodegenerative Process ◽  
Parp 1 ◽  
Shed Light

AbstractThe investigation of genetic forms of juvenile neurodegeneration could shed light on the causative mechanisms of neuronal loss. Schinzel-Giedion syndrome (SGS) is a fatal developmental syndrome caused by mutations in the SETBP1 gene, inducing the accumulation of its protein product. SGS features multi-organ involvement with severe intellectual and physical deficits due, at least in part, to early neurodegeneration. Here we introduce a human SGS model that displays disease-relevant phenotypes. We show that SGS neural progenitors exhibit aberrant proliferation, deregulation of oncogenes and suppressors, unresolved DNA damage, and resistance to apoptosis. Mechanistically, we demonstrate that high SETBP1 levels inhibit P53 function through the stabilization of SET, which in turn hinders P53 acetylation. We find that the inheritance of unresolved DNA damage in SGS neurons triggers the neurodegenerative process that can be alleviated either by PARP-1 inhibition or by NAD + supplementation. These results implicate that neuronal death in SGS originates from developmental alterations mainly in safeguarding cell identity and homeostasis.

scholarly journals Genomic instability of microsatellite repeats and its association with the evolution of chronic myelogenous leukemia [see comments]

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3449-3456 ◽  
Author(s):  
C Wada ◽  
S Shionoya ◽  
Y Fujino ◽  
H Tokuhiro ◽  
T Akahoshi ◽  
...  
Keyword(s):  
Genomic Instability ◽  
Chronic Myelogenous Leukemia ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Genetic Alterations ◽  
Myelogenous Leukemia ◽  
Leukemic Cells ◽  
Genetic Event ◽  
Familial Predisposition ◽  
Somatic Instability

Abstract Tumorigenesis has been shown to proceed through a series of genetic alterations involving protooncogenes and tumor-suppressor genes. Investigation of genomic instability of microsatellites has indicated a new mechanism for human carcinogenesis in hereditary nonpolyposis colorectal cancer and sporadic cancer and this instability has been shown to be related to inherited predisposition to cancer. This study was conducted to determine whether such microsatellite instability is associated with the evolution of chronic myelogenous leukemia (CML) to the blast crisis. Nineteen CML patients clinically progressing from the chronic phase to accelerated phase or blast crisis and 20 other patients in the CML chronic phase were studied. By polymerase chain reaction assay, DNAs for genomic instability in five separate microsatellites in chromosome arms 5q (Mfd27), 17p (Mfd41), 18q (DCC), 3p (CI3–9), and 8p (LPL) were examined. Differences in unrelated microsatellites of chronic and blastic phase DNAs in 14 of 19 patients (73.7%) were demonstrated. Somatic instability in five microsatellites, Mfd27, Mfd41, DCC, CI3–9, and LPL, was detected in 2 of 19 (10.5%), 8 of 19 (42.1%), 11 of 19 (57.9%), 4 of 17 (23.5%), and 4 of 17 (23.5%) cases. In 10 of 19 cases (52.6%), genetic instability in at least two of five microsatellites was observed and was categorized as replication error (RER+) phenotype. CML evolution cases with myeloid, lymphoid, and mixed phenotypes and the blast crisis and accelerated phase showed somatic instability in a number of microsatellites. No alterations in leukemic cells at the chronic phase could be detected in any microsatellites. These data indicate instability of microsatellites (RER+) but not familial predisposition to possibly be a late genetic event in the evolution of CML to blast crisis. In the microsatellite of the DCC gene, complicated alterations in band patterns caused by instability as well as loss of heterozygosity (LOH) were observed in 13 of 19 cases (68.4%): instability in 9 cases, instability plus LOH in 2 cases, and only LOH in 2 cases. These highly frequent alterations in microsatellites, including instability and LOH, suggesting that secondary events due possibly to loss of fidelity in replication and repair machinery may be significantly associated with CML evolution.

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.

scholarly journals Cell Cycle and DNA Repair Regulation in the Damage Response: Protein Phosphatases Take Over the Reins

2020 ◽  
Vol 21 (2) ◽  
pp. 446 ◽  
Author(s):  
Adrián Campos ◽  
Andrés Clemente-Blanco
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Protein Phosphatases ◽  
Genetic Material ◽  
Protein Composition ◽  
Genotoxic Stress ◽  
Damage Response ◽  
Protein Dephosphorylation

Cells are constantly suffering genotoxic stresses that affect the integrity of our genetic material. Genotoxic insults must be repaired to avoid the loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental abnormalities and tumorigenesis. To combat this threat, eukaryotic cells have evolved a set of sophisticated molecular mechanisms that are collectively known as the DNA damage response (DDR). This surveillance system controls several aspects of the cellular response, including the detection of lesions, a temporary cell cycle arrest, and the repair of the broken DNA. While the regulation of the DDR by numerous kinases has been well documented over the last decade, the complex roles of protein dephosphorylation have only recently begun to be investigated. Here, we review recent progress in the characterization of DDR-related protein phosphatases during the response to a DNA lesion, focusing mainly on their ability to modulate the DNA damage checkpoint and the repair of the damaged DNA. We also discuss their protein composition and structure, target specificity, and biochemical regulation along the different stages encompassed in the DDR. The compilation of this information will allow us to better comprehend the physiological significance of protein dephosphorylation in the maintenance of genome integrity and cell viability in response to genotoxic stress.

scholarly journals Involvement of POLA2 in Double Strand Break Repair and Genotoxic Stress

2020 ◽  
Vol 21 (12) ◽  
pp. 4245
Author(s):  
Tuyen T. Dang ◽  
Julio C. Morales
Keyword(s):  
Dna Damage ◽  
Genomic Instability ◽  
Dna Polymerase ◽  
Genotoxic Stress ◽  
Strand Break ◽  
Double Strand Break ◽  
Double Strand Break Repair ◽  
Dsb Repair ◽  
Dna Polymerase Alpha ◽  
Break Repair

Cellular survival is dependent on the efficient replication and transmission of genomic information. DNA damage can be introduced into the genome by several different methods, one being the act of DNA replication. Replication is a potent source of DNA damage and genomic instability, especially through the formation of DNA double strand breaks (DSBs). DNA polymerase alpha is responsible for replication initiation. One subunit of the DNA polymerase alpha replication machinery is POLA2. Given the connection between replication and genomic instability, we decided to examine the role of POLA2 in DSB repair, as little is known about this topic. We found that loss of POLA2 leads to an increase in spontaneous DSB formation. Loss of POLA2 also slows DSB repair kinetics after treatment with etoposide and inhibits both of the major double strand break repair pathways: non-homologous end-joining and homologous recombination. In addition, loss of POLA2 leads to increased sensitivity to ionizing radiation and PARP1 inhibition. Lastly, POLA2 expression is elevated in glioblastoma multiforme tumors and correlates with poor overall patient survival. These data demonstrate a role for POLA2 in DSB repair and resistance to genotoxic stress.

Internal tandem duplication of FLT3 (FLT3/ITD) induces increased ROS production, DNA damage, and misrepair: implications for poor prognosis in AML

Blood ◽  
2008 ◽  
Vol 111 (6) ◽  
pp. 3173-3182 ◽  
Author(s):  
Annahita Sallmyr ◽  
Jinshui Fan ◽  
Kamal Datta ◽  
Kyu-Tae Kim ◽  
Dan Grosu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Genomic Instability ◽  
Cell Lines ◽  
Poor Prognosis ◽  
Tandem Duplication ◽  
Ros Generation ◽  
Ros Production ◽  
Dna Double Strand Breaks ◽  
Internal Tandem Duplication ◽  
Downstream Signaling

Abstract Activating mutations of the FMS-like tyrosine kinase-3 (FLT3) receptor occur in approximately 30% of acute myeloid leukemia (AML) patients and, at least for internal tandem duplication (ITD) mutations, are associated with poor prognosis. FLT3 mutations trigger downstream signaling pathways including RAS-MAP/AKT kinases and signal transducer and activator of transcription-5 (STAT5). We find that FLT3/ITD mutations start a cycle of genomic instability whereby increased reactive oxygen species (ROS) production leads to increased DNA double-strand breaks (DSBs) and repair errors that may explain aggressive AML in FLT3/ITD patients. Cell lines transfected with FLT3/ITD and FLT3/ITD-positive AML cell lines and primary cells demonstrate increased ROS. Increased ROS levels appear to be produced via STAT5 signaling and activation of RAC1, an essential component of ROS-producing NADPH oxidases. A direct association of RAC1-GTP binding to phosphorylated STAT5 (pSTAT5) provides a possible mechanism for ROS generation. A FLT3 inhibitor blocked increased ROS in FLT3/ITD cells resulting in decreased DSB and increased repair efficiency and fidelity. Our study suggests that the aggressiveness of the disease and poor prognosis of AML patients with FLT3/ITD mutations could be the result of increased genomic instability that is driven by higher endogenous ROS, increased DNA damage, and decreased end-joining fidelity.

scholarly journals Ubiquitylation, neddylation and the DNA damage response

Open Biology ◽  
2015 ◽  
Vol 5 (4) ◽  
pp. 150018 ◽  
Author(s):  
Jessica S. Brown ◽  
Stephen P. Jackson
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Cellular Response ◽  
Dna Double Strand Breaks ◽  
Post Translational Modification ◽  
Strand Breaks ◽  
Damage Sensing ◽  
Damage Response ◽  
Repair Mechanisms ◽  
And Function

Failure of accurate DNA damage sensing and repair mechanisms manifests as a variety of human diseases, including neurodegenerative disorders, immunodeficiency, infertility and cancer. The accuracy and efficiency of DNA damage detection and repair, collectively termed the DNA damage response (DDR), requires the recruitment and subsequent post-translational modification (PTM) of a complex network of proteins. Ubiquitin and the ubiquitin-like protein (UBL) SUMO have established roles in regulating the cellular response to DNA double-strand breaks (DSBs). A role for other UBLs, such as NEDD8, is also now emerging. This article provides an overview of the DDR, discusses our current understanding of the process and function of PTM by ubiquitin and NEDD8, and reviews the literature surrounding the role of ubiquitylation and neddylation in DNA repair processes, focusing particularly on DNA DSB repair.

Sign in / Sign up

Export Citation Format

Share Document