Advancing maternal age compromises control of cell cycle checkpoint for aneuploidies in human embryos cultured in vitro

ABSTRACT Epstein-Barr virus (EBV) infects most of the human population and persists in B lymphocytes for the lifetime of the host. The establishment of latent infection by EBV requires the expression of a unique repertoire of genes. The product of one of these viral genes, the EBV nuclear antigen 3C (EBNA3C), is essential for the growth transformation of primary B lymphocytes in vitro and can regulate the transcription of a number of viral and cellular genes important for the immortalization process. This study demonstrates an associated function of EBNA3C which involves the disruption of the G2/M cell cycle checkpoint. We show that EBNA3C-expressing lymphoblastoid cell lines treated with the drug nocodazole, which is known to block cells at the G2/M transition, did not show a G2/M-specific checkpoint arrest. Analyses of the cell cycles of cells expressing EBNA3C demonstrated that the expression of this essential EBV nuclear antigen is capable of releasing the G2/M checkpoint arrest induced by nocodazole. This G2/M arrest in response to nocodazole was also abolished by caffeine, suggesting an involvement of the ATM/ATR signaling pathway in the regulation of this cell cycle checkpoint. Importantly, we show that the direct interaction of EBNA3C with Chk2, the ATM/ATR signaling effector, is responsible for the release of this nocodazole-induced G2/M arrest and that this interaction leads to the serine 216 phosphorylation of Cdc25c, which is sequestered in the cytoplasm by 14-3-3. Overall, our data suggest that EBNA3C can directly regulate the G2/M component of the host cell cycle machinery, allowing for the release of the checkpoint block.

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Immortalization-Upregulated Protein Promotes Pancreatic Cancer Progression By Regulating NPM1/FHL1-Mediated Cell-Cycle-Checkpoint Protein Activity

10.21203/rs.3.rs-1077168/v1 ◽

2021 ◽

Author(s):

Qiankun Luo ◽

Yanfeng Pan ◽

Qiang Fu ◽

Xu Zhang ◽

Shuai Zhou ◽

...

Keyword(s):

Cell Cycle ◽

Cell Proliferation ◽

Cell Cycle Arrest ◽

Cancer Progression ◽

Cell Cycle Checkpoint ◽

The Cancer Genome Atlas ◽

Ductal Adenocarcinoma ◽

Cycle Arrest ◽

Cycle Checkpoint

Abstract Immortalization-upregulated protein (IMUP) plays a vital role in cell proliferation and tumor progression. However, its role in pancreatic ductal adenocarcinoma (PDAC) remains unclear. Here, we select IMUP as an alternative gene based on GeneChip analysis of clinical PDAC tissues and transcriptome data from The Cancer Genome Atlas. IMUP expression is upregulated in PDAC tumor tissues. Moreover, high IMUP expression correlates with poor prognosis, while IMUP depletion inhibits PDAC cell proliferation and colony formation capacity in vitro, and decreases xenograft tumor growth in vivo. IMUP downregulation leads to cell-cycle arrest in the S phase. IMUP Knockdown increases the expression of four-and-a-half LIM domain protein 1 (FHL1), which regulates the phosphorylation of cell division cycle 25A (CDC25A) by cycle checkpoint kinase 1 (CHK1) and promotes cytoplasmic distribution of CDC25A by interaction with 14-3-3ξ. Furthermore, FHL1 knockdown restores the effects induced by IMUP depletion. liquid chromatography tandem mass spectrometry and immunoprecipitation analysis further show that IMUP interacts directly with nucleophosmin (NPM1) and enhances its stability. DNA methylation sequencing shows that FHL1 promoter methylation decreases when IMUP is downregulated. Overexpression of NPM1 can increase the methylation level of FHL1, thereby decreasing its expression. Our study provides a novel perspective on IMUP/NPM1/FHL1-mediated cell-cycle arrest by regulating CDC25A phosphorylation in PDAC. These findings may provide a new therapeutic target for PDAC.

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Spermidine/spermine N1-acetyltransferase overexpression in kidney epithelial cells disrupts polyamine homeostasis, leads to DNA damage, and causes G2 arrest

AJP Cell Physiology ◽

10.1152/ajpcell.00451.2006 ◽

2007 ◽

Vol 292 (3) ◽

pp. C1204-C1215 ◽

Cited By ~ 37

Author(s):

Kamyar Zahedi ◽

John J. Bissler ◽

Zhaohui Wang ◽

Anuradha Josyula ◽

Lu Lu ◽

...

Keyword(s):

Cell Cycle ◽

Cell Proliferation ◽

Dna Damage ◽

Dna Repair ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Dna Lesions ◽

Cell Cycle Checkpoint ◽

Cycle Checkpoint

Expression of spermidine/spermine N1-acetyltransferase (SSAT) increases in kidneys subjected to ischemia-reperfusion injury (IRI). Increased expression of SSAT in vitro leads to alterations in cellular polyamine content, depletion of cofactors and precursors of polyamine synthesis, and reduced cell proliferation. In our model system, a >28-fold increase in SSAT levels in HEK-293 cells leads to depletion of polyamines and elevation in the enzymatic activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase, suggestive of a compensatory reaction to increased polyamine catabolism. Increased expression of SSAT also led to DNA damage and G2 arrest. The increased DNA damage was primarily due to the depletion of polyamines. Other factors such as increased production of H2O2 due to polyamine oxidase activity may play a secondary role in the induction of DNA lesions. In response to DNA damage the ATM/ATR → Chk1/2 DNA repair and cell cycle checkpoint pathways were activated, mediating the G2 arrest in SSAT-expressing cells. In addition, the activation of ERK1 and ERK2, which play integral roles in the G2/M transition, is impaired in cells expressing SSAT. These results indicate that the disruption of polyamine homeostasis due to enhanced SSAT activity leads to DNA damage and reduced cell proliferation via activation of DNA repair and cell cycle checkpoint and disruption of Raf → MEK → ERK pathways. We propose that in kidneys subjected to IRI, one mechanism through which increased expression of SSAT may cause cellular injury and organ damage is through induction of DNA damage and the disruption of cell cycle.

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A new in vitro system for activating the cell cycle checkpoint

Cell Cycle ◽

10.4161/cc.10.3.14753 ◽

2011 ◽

Vol 10 (3) ◽

pp. 500-506 ◽

Cited By ~ 12

Author(s):

Jingna Wang ◽

Staci Engle ◽

Youwei Zhang

Keyword(s):

Cell Cycle ◽

Cell Cycle Checkpoint ◽

In Vitro System ◽

Cycle Checkpoint

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WEE1 kinase is a therapeutic vulnerability in CIC-DUX4 undifferentiated sarcoma.

10.1101/2021.06.21.448439 ◽

2021 ◽

Author(s):

Rovingaile Kriska Ponce ◽

Nicholas J Thomas ◽

Nam Q Bui ◽

Tadashi Kondo ◽

Ross A Okimoto

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Cell Cycle Checkpoint ◽

M Cell ◽

Undifferentiated Sarcoma ◽

Cycle Checkpoint ◽

Wee1 Kinase ◽

Apoptotic Induction

CIC-DUX4 rearrangements define an aggressive and chemotherapy-insensitive subset of undifferentiated sarcomas. The CIC-DUX4 fusion drives oncogenesis through direct transcriptional upregulation of cell cycle and DNA replication genes. Notably, CIC-DUX4-mediated CCNE1 upregulation compromises the G1/S transition, conferring a potential survival dependence on the G2/M cell cycle checkpoint. Through an integrative transcriptional and kinase activity screen using patient-derived specimens, we now show that CIC-DUX4 sarcomas depend on the G2/M checkpoint regulator, WEE1, as an adaptive survival mechanism. Specifically, CIC-DUX4 sarcomas depend on WEE1 activity to limit DNA damage and unscheduled mitotic entry. Consequently, genetic or pharmacologic WEE1 inhibition in vitro and in vivo leads to rapid DNA damage-associated apoptotic induction of patient-derived CIC-DUX4 sarcomas. Thus, we identify WEE1 as an actionable therapeutic vulnerability in CIC-DUX4 sarcomas.

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