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

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

Science Advances ◽

10.1126/sciadv.aav1118 ◽

2019 ◽

Vol 5 (3) ◽

pp. eaav1118 ◽

Cited By ~ 19

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.

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Kinome-Wide shRNA Screen Reveals Functional Connections Between FANCA, Mitotic Centrosomes and the Spindle Assembly Checkpoint Tumor Suppressor Pathways

Blood ◽

10.1182/blood.v126.23.3612.3612 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3612-3612

Author(s):

Richa Sharma ◽

Zahi Abdul Sater ◽

Rikki Enzor ◽

Ying He ◽

Grzegorz Nalepa

Keyword(s):

Dna Damage ◽

Tumor Suppressor ◽

Fanconi Anemia ◽

Cross Talk ◽

Spindle Assembly Checkpoint ◽

Spindle Assembly ◽

Mitotic Checkpoint ◽

Synthetic Lethal ◽

Shrna Screen

Abstract Fanconi anemia (FA) is a genetic disorder characterized by progressive bone marrow failure, congenital abnormalities and predilection towards development of hematopoietic malignancies, including acute myeloid leukemia (AML). Congenital biallelic disruption of the FA/BRCA signaling network causes Fanconi anemia and somatic mutations within the same genes are increasingly identified in a variety of malignancies in non-FA individuals, consistent with the critical role of this signaling pathway in FA and in the general population. The FA/BRCA tumor suppressor network orchestrates interphase DNA-damage repair (DDR) and DNA replication to maintain genomic stability. Additionally, we and others have demonstrated that the genome housekeeping function of FA/BRCA signaling extends beyond interphase: loss of FA/BRCA signaling perturbs execution of mitosis, including the spindle assembly checkpoint (SAC), centrosome maintenance, cytokinesis and resolution of anaphase DNA bridges. Interphase errors exacerbate mitotic abnormalities and mitotic failure promotes interphase mutagenesis. Consequently, we had demonstrated that primary FA patients' cells accumulate genomic abnormalities consistent with a dual mechanism of impaired interphase DDR/replication and defective mitosis. Previous detailed studies had elucidated multiple mechanisms of interphase DDR-dependent assembly and activation of the FA complex at DNA damage sites to arrest the cell cycle and repair DNA lesions. However, the signaling cross-talk nodes between the FA and mitotic checkpoint pathways remain to be discovered. In this study, we identified functionally relevant mitotic signaling defects resulting from FANCA deficiency via a synthetic lethal kinome-wide pooled shRNA screen in primary patient-derived FANCA -deficient cells compared to isogenic FANCA -corrected cell line. Bioinformatics analysis of our screen results followed by secondary validation of selected hits with alternative shRNAs and small-molecule inhibitors revealed conserved mitotic signal transduction pathways regulating the SAC and centrosome maintenance. Our super-resolution structured illumination (SR-SIM) microscopy coupled with deconvolution imaging revealed that a fraction of FANCA co-localizes with key SAC kinases at mitotic centrosomes and kinetochores, consistent with the role of FANCA in centrosome maintenance and the SAC. Co-immunoprecipitation assays identified the biochemical interaction between FANCA and an essential SAC kinase whose loss is synthetic lethal with FANCA deficiency, providing first insights into the interactions between FA signaling and the canonical SAC network. Together, our study has unraveled functional and biochemical connections between FANCA and the centrosome/SAC kinases, consistent with the essential role of FANCA in cell division. Our ongoing work is aimed at mechanistically dissecting molecular links between these two key tumor suppressor signaling pathways in more detail. We hypothesize that impaired FANCA/SAC cross-talk may contribute to genomic instability in FA-deficient cells and provide opportunities to selectively kill FANCA-/- cells. Disclosures No relevant conflicts of interest to declare.

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CHK1 monitors spindle assembly checkpoint and DNA damage repair during the first cleavage of mouse early embryos

Cell Proliferation ◽

10.1111/cpr.12895 ◽

2020 ◽

Vol 53 (10) ◽

Cited By ~ 2

Author(s):

Jia‐Qian Ju ◽

Xiao‐Han Li ◽

Meng‐Hao Pan ◽

Yao Xu ◽

Ming‐Hong Sun ◽

...

Keyword(s):

Dna Damage ◽

Spindle Assembly Checkpoint ◽

Dna Damage Repair ◽

Spindle Assembly ◽

Damage Repair ◽

Early Embryos

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Nucleolar and spindle associated protein 1 enhances chemoresistance through DNA damage repair pathway in chronic lymphocytic leukemia by binding with RAD51

Cell Death and Disease ◽

10.1038/s41419-021-04368-2 ◽

2021 ◽

Vol 12 (11) ◽

Author(s):

Yang Han ◽

Xinting Hu ◽

Xiaoya Yun ◽

Jiarui Liu ◽

Juan Yang ◽

...

Keyword(s):

Dna Damage ◽

Chronic Lymphocytic Leukemia ◽

Dna Damage Repair ◽

Chemotherapy Resistance ◽

Lymphocytic Leukemia ◽

Damage Repair ◽

G1 Phase Arrest ◽

Chromosome Attachment

AbstractNucleolar and spindle-associated protein 1 (NUSAP1) is an essential regulator of mitotic progression, spindle assembly, and chromosome attachment. Although NUSAP1 acts as an oncogene involved in the progression of several cancers, the exact role of chronic lymphocytic leukemia (CLL) remains elusive. Herein, we first discovered obvious overexpression of NUSAP1 in CLL associated with poor prognosis. Next, the NUSAP1 level was modulated by transfecting CLL cells with lentivirus. Silencing NUSAP1 inhibited the cell proliferation, promoted cell apoptosis and G0/G1 phase arrest. Mechanistically, high expression of NUSAP1 strengthened DNA damage repairing with RAD51 engagement. Our results also indicated that NUSAP1 knockdown suppressed the growth CLL cells in vivo. We further confirmed that NUSAP1 reduction enhanced the sensitivity of CLL cells to fludarabine or ibrutinib. Overall, our research investigates the mechanism by which NUSAP1 enhances chemoresistance via DNA damage repair (DDR) signaling by stabilizing RAD51 in CLL cells. Hence, NUSAP1 may be expected to be a perspective target for the treatment of CLL with chemotherapy resistance.

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Impaired Spindle Assembly Checkpoint In Vivo Promotes MDS/AML in a Novel Mouse Model of Fanconi Anemia

Blood ◽

10.1182/blood.v126.23.1211.1211 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1211-1211

Author(s):

Donna Cerabona ◽

Zahi Abdul Sater ◽

Elizabeth Sierra Potchanant ◽

Ying He ◽

Zejin Sun ◽

...

Keyword(s):

Bone Marrow ◽

Mouse Model ◽

Genomic Instability ◽

Chromosome Segregation ◽

Fanconi Anemia ◽

Chromosomal Instability ◽

Spindle Assembly Checkpoint ◽

Bone Marrow Failure

Abstract The Fanconi anemia (FA/BRCA) signaling network prevents bone marrow failure and cancer by protecting genomic integrity. Biallelic germline mutations within this gene network result in Fanconi anemia, an inherited bone marrow failure syndrome characterized by genomic instability and a predisposition to bone marrow failure, myelodysplasia and cancer, particularly acute myelogenous leukemia (AML). Heterozygous inborn mutations in the BRCA branch of FA network increase risk of breast and ovarian cancers as well as other tumors, and somatic mutations of FA/BRCA genes occur in malignancies in non-Fanconi patients. Thus, disruption of FA/BRCA signaling promotes malignancies in the inherited genetic syndromes and in the general population. The FA/BRCA network functions as a genome gatekeeper throughout the cell cycle. In interphase, the FA/BRCA network provides a crucial line of defense against mutagenesis by coordinating DNA damage response to a variety of genotoxic insults, from endogenous aldehydes to replication errors and mutagen exposure. Less is known about the role of the FA/BRCA pathway during mitosis. However, FA signaling has recently been implicated in multiple aspects of cell division, including the spindle assembly checkpoint (SAC) that ensures high-fidelity chromosome segregation at metaphase to anaphase transition; cytokinesis; centrosome maintenance and repair of ultrafine anaphase bridges. Although chromosomal instability due to mitotic errors is a hallmark of cancer, the in vivo contribution of abnormal mitosis to malignant transformation of FA-deficient hematopoietic cells remains unknown. To determine whether error-prone chromosome segregation upon loss of FA signaling contributes to abnormal hematopoiesis and cancer, we generated a novel murine FA model by genetically weakening the SAC in the FA-deficient background. The resulting mice were viable and born at expected Mendelian ratios, but exhibited increased baseline in vivo chromosomal instability evidenced by elevated red blood cell micronucleation, increased frequency of chromosome missegregation and DNA breakage in microscopy-based cytome assays, and augmented bone marrow karyotype instability. Importantly, unlike FA or SAC control animals, the FA-SAC mice were prone to premature death due to the development of myelodysplasia and AML at young age, recapitulating disease manifestations of human Fanconi anemia. This study provides the in vivo evidence supporting the essential role of compromised chromosome segregation in the development of myelodysplasia and acute leukemia due to impaired FA signaling. Our observations provide novel insights into complex mechanisms of genomic instability and carcinogenesis due to FA deficiency. Impaired mitosis is a well-established therapeutic target, and our independent ex vivo experiments using FA patient-derived primary cells show that exposure to antimitotic chemotherapeutics is synthetic lethal with loss of the FA network. Thus, our findings may have implications for future precision strategies against FA-deficient, chromosomally unstable hematopoietic cancers. The FA-SAC mouse model offers a preclinical platform to systematically test this hypothesis in vivo. Disclosures No relevant conflicts of interest to declare.

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GTSE1 is possibly involved in the DNA damage repair and cisplatin resistance in osteosarcoma

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-021-02859-8 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Chaofan Xie ◽

Wei Xiang ◽

Huiyong Shen ◽

Jingnan Shen

Keyword(s):

Dna Damage ◽

Dna Replication ◽

Cell Lines ◽

Cell Cycle Progression ◽

Cisplatin Resistance ◽

Dna Damage Repair ◽

Loss Of Function ◽

Damage Repair

Abstract Background G2 and S phase-expressed-1 (GTSE1) negatively regulates the tumor-suppressive protein p53 and is potentially correlated with chemoresistance of cancer cells. This study aims to explore the effect of GTSE1 on the DNA damage repair and cisplatin (CDDP) resistance in osteosarcoma (OS). Materials and methods Expression of GTSE1 in OS was predicted in bioinformatics system GEPIA and then validated in clinically obtained tissues and acquired cell lines using RT-qPCR, immunohistochemical staining, and western blot assays. Gain- and loss-of-function studies of GTSE1 were performed in MG-63 and 143B cells to examine its function in cell cycle progression, DNA replication, and CDDP resistance. Stably transfected MG-63 cells were administrated into mice, followed by CDDP treatment to detect the role of GTSE1 in CDDP resistance in vivo. Results GTSE1 was highly expressed in patients with OS and correlated with poor survival according to the bioinformatics predictions. Elevated GTSE1 expression was detected in OS tissues and cell lines. GTSE1 silencing reduced S/G2 transition and DNA replication, and it increased the CDDP sensitivity and decreased the expression of DNA repair-related biomarkers in MG-63 cells. GTSE1 overexpression in 143B cells led to inverse trends. In vivo, downregulation of GTSE1 strengthened the treating effect of CDDP and significantly repressed growth of xenograft tumors in nude mice. However, overexpression of GTSE1 blocked the anti-tumor effect of CDDP. Conclusion This study demonstrates that GTSE1 is possibly involved in the DNA damage repair and cisplatin resistance in OS.

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BRCA1 Regulation of Fanconi Anemia Proteins in DNA Damage Repair

10.21236/ada435068 ◽

2005 ◽

Author(s):

Woo-Hyun Park

Keyword(s):

Dna Damage ◽

Fanconi Anemia ◽

Dna Damage Repair ◽

Damage Repair

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

Cell Death and Disease ◽

10.1038/s41419-021-03728-2 ◽

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.

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

Cell Death and Disease ◽

10.1038/s41419-020-2708-5 ◽

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.

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