SPOP mutation induces replication over-firing by impairing Geminin ubiquitination and triggers replication catastrophe upon ATR inhibition

AbstractGeminin and its binding partner Cdt1 are essential for the regulation of DNA replication. Here we show that the CULLIN3 E3 ubiquitin ligase adaptor protein SPOP binds Geminin at endogenous level and regulates DNA replication. SPOP promotes K27-linked non-degradative poly-ubiquitination of Geminin at lysine residues 100 and 127. This poly-ubiquitination of Geminin prevents DNA replication over-firing by indirectly blocking the association of Cdt1 with the MCM protein complex, an interaction required for DNA unwinding and replication. SPOP is frequently mutated in certain human cancer types and implicated in tumorigenesis. We show that cancer-associated SPOP mutations impair Geminin K27-linked poly-ubiquitination and induce replication origin over-firing and re-replication. The replication stress caused by SPOP mutations triggers replication catastrophe and cell death upon ATR inhibition. Our results reveal a tumor suppressor role of SPOP in preventing DNA replication over-firing and genome instability and suggest that SPOP-mutated tumors may be susceptible to ATR inhibitor therapy.

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The E3 Ubiquitin Ligase TBK1 Mediates the Degradation of Multiple Picornavirus VP3 Proteins by Phosphorylation and Ubiquitination

Journal of Virology ◽

10.1128/jvi.01438-19 ◽

2019 ◽

Vol 93 (23) ◽

Cited By ~ 4

Author(s):

Dan Li ◽

Wenping Yang ◽

Jingjing Ren ◽

Yi Ru ◽

Keshan Zhang ◽

...

Keyword(s):

Ubiquitin Ligase ◽

Molecular Mechanisms ◽

E3 Ubiquitin Ligase ◽

Adaptor Protein ◽

Ubiquitin Ligase Activity ◽

Lysine Residues ◽

Innate Antiviral Immunity

ABSTRACT TANK-binding kinase 1 (TBK1) is essential for interferon beta (IFN-β) production and innate antiviral immunity. However, other, additional functions of TBK1 have remained elusive. Here, we showed that TBK1 is an E3 ubiquitin ligase that undergoes self-ubiquitylation in vitro in the presence of the E2 enzyme UbcH5c. Further evidence showed that TBK1 could also be self-ubiquitylated in vivo. Importantly, multiple picornavirus VP3 proteins were degraded by TBK1 through its kinase and E3 ubiquitin ligase activity. Mechanistically, TBK1 phosphorylated multiple picornavirus VP3 proteins at serine residues and ubiquitinated them via K63-linked ubiquitination at lysine residues. In addition, the C426 and C605 residues of TBK1 were not essential for TBK1 innate immunity activity; however, these residues were required for degradation of multiple picornavirus VP3 proteins and for its E3 ubiquitin ligase activity. Hence, our findings identified a novel role of TBK1 in regulating the virus life cycle and provided new insights into the molecular mechanisms of TBK1-mediated antiviral response. IMPORTANCE TBK1 is an important adaptor protein required for innate immune response to viruses, but its other functions were unknown. In this study, we found that TBK1 is an E3 ubiquitin ligase that undergoes self-ubiquitylation in vitro in the presence of the E2 enzyme UbcH5c. In addition, multiple picornavirus VP3 proteins were degraded by TBK1 through its kinase and E3 ubiquitin ligase activity. Our report provides evidence that TBK1 plays a role in viral protein degradation.

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Histone Modifying Enzymes in Gynaecological Cancers

Cancers ◽

10.3390/cancers13040816 ◽

2021 ◽

Vol 13 (4) ◽

pp. 816

Author(s):

Priya Ramarao-Milne ◽

Olga Kondrashova ◽

Sinead Barry ◽

John D. Hooper ◽

Jason S. Lee ◽

...

Keyword(s):

Genome Instability ◽

Cpg Islands ◽

Gene Promoter ◽

Driver Mutations ◽

Promoter Regions ◽

Post Translational Modifications ◽

Chromatin Dynamics ◽

Cancer Types ◽

Histone Modifying Enzymes

Genetic and epigenetic factors contribute to the development of cancer. Epigenetic dysregulation is common in gynaecological cancers and includes altered methylation at CpG islands in gene promoter regions, global demethylation that leads to genome instability and histone modifications. Histones are a major determinant of chromosomal conformation and stability, and unlike DNA methylation, which is generally associated with gene silencing, are amenable to post-translational modifications that induce facultative chromatin regions, or condensed transcriptionally silent regions that decondense resulting in global alteration of gene expression. In comparison, other components, crucial to the manipulation of chromatin dynamics, such as histone modifying enzymes, are not as well-studied. Inhibitors targeting DNA modifying enzymes, particularly histone modifying enzymes represent a potential cancer treatment. Due to the ability of epigenetic therapies to target multiple pathways simultaneously, tumours with complex mutational landscapes affected by multiple driver mutations may be most amenable to this type of inhibitor. Interrogation of the actionable landscape of different gynaecological cancer types has revealed that some patients have biomarkers which indicate potential sensitivity to epigenetic inhibitors. In this review we describe the role of epigenetics in gynaecological cancers and highlight how it may exploited for treatment.

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Long noncoding RNA ANRIL as a novel biomarker in human cancer

Future Oncology ◽

10.2217/fon-2020-0470 ◽

2020 ◽

Vol 16 (35) ◽

pp. 2981-2995

Author(s):

Ning Lou ◽

Guohong Liu ◽

Yunbao Pan

Keyword(s):

Long Noncoding Rna ◽

Noncoding Rna ◽

Cell Cycle Progression ◽

Potential Role ◽

Human Cancer ◽

Cycle Progression ◽

Diagnosis And Prognosis ◽

Cancer Types ◽

Cancer Medicine

The long noncoding RNA ANRIL, located in the human chromosome 9p21 region, has been reported to be involved in tumor progression. ANRIL regulates gene expression via recruiting PRC2 or titrating miRNA; it also participates in signaling pathways. Evidence has indicated that ANRIL is overexpressed in many cancer types and is capable of enhancing cell proliferation and cell cycle progression and inhibiting apoptosis and senescence. ANRIL has the potential to serve as a biomarker for diagnosis and prognosis in cancer. In this article we focus on recent advances in studies of the oncogenic role of ANRIL and its potential role in cancer medicine.

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Heat Shock Proteins Are Essential Components in Transformation and Tumor Progression: Cancer Cell Intrinsic Pathways and Beyond

International Journal of Molecular Sciences ◽

10.3390/ijms20184507 ◽

2019 ◽

Vol 20 (18) ◽

pp. 4507 ◽

Cited By ~ 13

Author(s):

Lang ◽

Guerrero-Giménez ◽

Prince ◽

Ackerman ◽

Bonorino ◽

...

Keyword(s):

Heat Shock ◽

Cancer Cells ◽

Stress Proteins ◽

De Novo ◽

Human Cancer ◽

Essential Components ◽

Wide Range ◽

Cancer Types ◽

Shock Proteins

Heat shock protein (HSP) synthesis is switched on in a remarkably wide range of tumor cells, in both experimental animal systems and in human cancer, in which these proteins accumulate in high levels. In each case, elevated HSP concentrations bode ill for the patient, and are associated with a poor outlook in terms of survival in most cancer types. The significance of elevated HSPs is underpinned by their essential roles in mediating tumor cell intrinsic traits such as unscheduled cell division, escape from programmed cell death and senescence, de novo angiogenesis, and increased invasion and metastasis. An increased HSP expression thus seems essential for tumorigenesis. Perhaps of equal significance is the pronounced interplay between cancer cells and the tumor milieu, with essential roles for intracellular HSPs in the properties of the stromal cells, and their roles in programming malignant cells and in the release of HSPs from cancer cells to influence the behavior of the adjacent tumor and infiltrating the normal cells. These findings of a triple role for elevated HSP expression in tumorigenesis strongly support the targeting of HSPs in cancer, especially given the role of such stress proteins in resistance to conventional therapies.

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MRE11-RAD50-NBS1 activates Fanconi Anemia R-loop suppression at transcription-replication conflicts

10.1101/472654 ◽

2018 ◽

Author(s):

Emily Yun-chia Chang ◽

James P. Wells ◽

Shu-Huei Tsai ◽

Yan Coulombe ◽

Yujia A. Chan ◽

...

Keyword(s):

Dna Replication ◽

Fanconi Anemia ◽

Replication Fork ◽

Genome Instability ◽

Human Cancer ◽

Replication Stress ◽

Maintenance Factors ◽

Genome Wide ◽

A Genome ◽

Dna Replication Stress

SUMMARYEctopic R-loop accumulation causes DNA replication stress and genome instability. To avoid these outcomes, cells possess a range of anti-R-loop mechanisms, including RNaseH that degrades the RNA moiety in R-loops. To comprehensively identify anti-R-loop mechanisms, we performed a genome-wide trigenic interaction screen in yeast lacking RNH1 and RNH201. We identified >100 genes critical for fitness in the absence of RNaseH, which were enriched for DNA replication fork maintenance factors such as RAD50. We show in yeast and human cells that R-loops accumulate during RAD50 depletion. In human cancer cell models, we find that RAD50 and its partners in the MRE11-RAD50-NBS1 complex regulate R-loop-associated DNA damage and replication stress. We show that a non-nucleolytic function of MRE11 is important for R-loop suppression via activation of PCNA-ubiquitination by RAD18 and recruiting anti-R-loop helicases in the Fanconi Anemia pathway. This work establishes a novel role for MRE11-RAD50-NBS1 in directing tolerance mechanisms of transcription-replication conflicts.

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Meiosis and Kinetochore genes are used by cancer cells as genome destabilizers and transformation catalysts

10.1101/826081 ◽

2019 ◽

Author(s):

Roshina Thapa ◽

Swetha Vasudevan ◽

Mimi Abo-Ayoub Ashqar ◽

Eli Reich ◽

Nataly Kravchenko-Balasha ◽

...

Keyword(s):

Cancer Cells ◽

Cancer Progression ◽

Genome Instability ◽

Chromosome Instability ◽

Information Theoretic ◽

Cancer Types ◽

Altered Gene ◽

The Relationship ◽

Hct116 Cells

AbstractCancer cells have an altered transcriptome which contributes to their altered behaviors compared to normal cells. Indeed, many tumors express high levels of genes participating in meiosis or kinetochore biology, but the role of this high expression has not been fully elucidated. In this study we explore the relationship between this overexpression and genome instability and transformation capabilities of cancer cells. For this, we obtained expression data from 5 different cancer types which were analyzed using computational information-theoretic analysis. We were able to show that highly expressed meiotic/kinetochore genes were enriched in the altered gene expression subnetworks characterizing unstable cancer types with high chromosome instability (CIN). However, altered subnetworks found in the cancers with low CIN did not include meiotic and kinetochore genes. Representative gene candidates, found by the analysis to be correlated with a CIN phenotype, were further explored by transfecting genomically-stable (HCT116) and unstable (MCF7) cancer cell lines with vectors overexpressing those genes. This overexpression resulted in an increase in the numbers of abnormal cell divisions and defective spindle formations and in increased transformation properties in stable cancer HCT116 cells. Interestingly, the same properties were less affected by the overexpressed genes in the unstable MCF7 cancer cells. Our results indicate that overexpression of both meiosis and kinetochore genes is capable of driving genomic instability and cancer progression.

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SGK1 in Human Cancer: Emerging Roles and Mechanisms

Frontiers in Oncology ◽

10.3389/fonc.2020.608722 ◽

2021 ◽

Vol 10 ◽

Author(s):

Yiwen Sang ◽

Piaoping Kong ◽

Shizhen Zhang ◽

Lingyu Zhang ◽

Ying Cao ◽

...

Keyword(s):

Cancer Progression ◽

Kinase Activity ◽

Human Cancer ◽

Therapy Resistance ◽

Cancer Cell Proliferation ◽

Serine Threonine Kinase ◽

Aberrant Expression ◽

Threonine Kinase ◽

Cancer Types

Serum and glucocorticoid-induced protein kinase 1 (SGK1) is a member of the “AGC” subfamily of protein kinases, which shares structural and functional similarities with the AKT family of kinases and displays serine/threonine kinase activity. Aberrant expression of SGK1 has profound cellular consequences and is closely correlated with human cancer. SGK1 is considered a canonical factor affecting the expression and signal transduction of multiple genes involved in the genesis and development of many human cancers. Abnormal expression of SGK1 has been found in tissue and may hopefully become a useful indicator of cancer progression. In addition, SGK1 acts as a prognostic factor for cancer patient survival. This review systematically summarizes and discusses the role of SGK1 as a diagnostic and prognostic biomarker of diverse cancer types; focuses on its essential roles and functions in tumorigenesis, cancer cell proliferation, apoptosis, invasion, metastasis, autophagy, metabolism, and therapy resistance and in the tumor microenvironment; and finally summarizes the current understanding of the regulatory mechanisms of SGK1 at the molecular level. Taken together, this evidence highlights the crucial role of SGK1 in tumorigenesis and cancer progression, revealing why it has emerged as a potential target for cancer therapy.

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Deficiency of BPOZ2 Decreases Liver Fibrosis After Chronic Carbon Tetrachloride Administration in Mice

International Journal of Toxicology ◽

10.1177/1091581814566472 ◽

2015 ◽

Vol 34 (2) ◽

pp. 204-210

Author(s):

Feng Zhang ◽

Suying Dang ◽

Runzhe Shu ◽

Yougui Xiang ◽

Ying Kuang ◽

...

Keyword(s):

Carbon Tetrachloride ◽

Liver Fibrosis ◽

Ubiquitin Ligase ◽

Adaptor Protein ◽

Matrix Metalloprotease ◽

Carbon Tetrachloride Administration ◽

Broad Complex ◽

Sustained Activation

Bood POZ containing gene type 2 (BPOZ2), a Broad-Complex, Tramtrack, and Bric a brac domain containing protein, is an adaptor protein for the E3 ubiquitin ligase scaffold protein CUL3. It plays an important role in acute carbon tetrachloride (CCl4)-induced liver injury and regeneration in mice. In this study, we investigated the role of BPOZ2 in the process of liver fibrosis induced by chronic CCl4 treatment. The results indicate that BPOZ2 deficiency decreases sustained activation of hepatic stellate cells, attenuates collagen αI(I) and tissue inhibitor of matrix metalloprotease 1 expression, and decreases liver fibrosis after repeated CCl4 administration. These findings suggest BPOZ2 as a new therapeutic target for the prevention and treatment of hepatic fibrosis in chronic liver disease.

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Overexpression of p75NTR in Human Seminoma: A New Biomarker?

Life ◽

10.3390/life11070629 ◽

2021 ◽

Vol 11 (7) ◽

pp. 629

Author(s):

Anna Perri ◽

Vittoria Rago ◽

Rocco Malivindi ◽

Lorenza Maltese ◽

Danilo Lofaro ◽

...

Keyword(s):

Human Cancer ◽

Germ Cell Tumors ◽

Receptor Protein ◽

Specific Marker ◽

Nuclear Staining ◽

Trka Receptor ◽

Testicular Germ Cell ◽

Cancer Types ◽

First Time

Several studies have demonstrated that the p75NTR low-affinity receptor of Nerve Growth Factor (NGF), is produced in abnormally large amounts in several human cancer types. However, the role of p75NTR varies substantially depending on cell context, so that a dual role of this receptor protein in tumor cell survival and invasion, as well as cell death, has been supported in recent studies. Herein we explored for the first time the expression of p75NTR in human specimens (nr = 40) from testicular germ cell tumors (TGCTs), mostly seminomas. Nuclear overexpression of p75NTR was detected by immunohistochemistry in seminoma tissue as compared to normal tissue, whereas neither NGF nor its high-affinity TrkA receptor was detected. An increased nuclear staining of phospho-JNK, belonging to the p75NTR signaling pathway and its pro-apoptotic target gene, p53, was concomitantly observed. Interestingly, our analysis revealed that decreased expression frequency of p75NTR, p-JNK and p53 was related to staging progression, thus suggesting that p75NTR may represent a specific marker for seminoma and staging in TGCTs.

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Separable functions of Tof1/Timeless in intra-S-checkpoint signalling, replisome stability and DNA topological stress

Nucleic Acids Research ◽

10.1093/nar/gkaa963 ◽

2020 ◽

Vol 48 (21) ◽

pp. 12169-12187

Author(s):

Rose Westhorpe ◽

Andrea Keszthelyi ◽

Nicola E Minchell ◽

David Jones ◽

Jonathan Baxter

Keyword(s):

Saccharomyces Cerevisiae ◽

Dna Replication ◽

Replication Stress ◽

Dna Helicase ◽

The Other ◽

Checkpoint Activation ◽

Replication Checkpoint ◽

Binding Partner ◽

Dna Replication Checkpoint

Abstract The highly conserved Tof1/Timeless proteins minimise replication stress and promote normal DNA replication. They are required to mediate the DNA replication checkpoint (DRC), the stable pausing of forks at protein fork blocks, the coupling of DNA helicase and polymerase functions during replication stress (RS) and the preferential resolution of DNA topological stress ahead of the fork. Here we demonstrate that the roles of the Saccharomyces cerevisiae Timeless protein Tof1 in DRC signalling and resolution of DNA topological stress require distinct N and C terminal regions of the protein, whereas the other functions of Tof1 are closely linked to the stable interaction between Tof1 and its constitutive binding partner Csm3/Tipin. By separating the role of Tof1 in DRC from fork stabilisation and coupling, we show that Tof1 has distinct activities in checkpoint activation and replisome stability to ensure the viable completion of DNA replication following replication stress.

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