BI-2536 Promotes Neuroblastoma Cell Death via Minichromosome Maintenance Complex Components 2 and 10

DNA replication is initiated with the recognition of the starting point of multiple replication forks by the origin recognition complex and activation of the minichromosome maintenance complex 10 (MCM10). Subsequently, DNA helicase, consisting of the MCM protein subunits MCM2-7, unwinds double-stranded DNA and DNA synthesis begins. In previous studies, replication factors have been used as clinical targets in cancer therapy. The results showed that MCM2 could be a proliferation marker for numerous types of malignant cancer. We analyzed samples obtained from patients with neuroblastoma, revealing that higher levels of MCM2 and MCM10 mRNA were associated with poor survival rate. Furthermore, we combined the results of the perturbation-induced reversal effects on the expression levels of MCM2 and MCM10 and the sensitivity correlation between perturbations and MCM2 and MCM10 from the Cancer Therapeutics Response Portal database. Small molecule BI-2536, a polo-like kinase 1 (PLK-1) inhibitor, is a candidate for the inhibition of MCM2 and MCM10 expression. To test this hypothesis, we treated neuroblastoma cells with BI-2536. The results showed that the drug decreased cell viability and reduced the expression levels of MCM2 and MCM10. Functional analysis further revealed enrichments of gene sets involved in mitochondria, cell cycle, and DNA replication for BI-2536-perturbed transcriptome. We used cellular assays to demonstrate that BI-2536 promoted mitochondria fusion, G2/M arrest, and apoptosis. In summary, our findings provide a new strategy for neuroblastoma therapy with BI-2536.

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Regulation of Replication Licensing by Acetyltransferase Hbo1

Molecular and Cellular Biology ◽

10.1128/mcb.26.3.1098-1108.2006 ◽

2006 ◽

Vol 26 (3) ◽

pp. 1098-1108 ◽

Cited By ~ 132

Author(s):

Masayoshi Iizuka ◽

Tomoko Matsui ◽

Haruhiko Takisawa ◽

M. Mitchell Smith

Keyword(s):

Dna Replication ◽

Origin Recognition Complex ◽

Cyclin Dependent Kinase ◽

Chromatin Binding ◽

Regulatory Factor ◽

Minichromosome Maintenance ◽

Egg Extracts ◽

Sequential Binding ◽

Initiation Of Dna Replication ◽

Prereplicative Complex

ABSTRACT The initiation of DNA replication is tightly regulated in eukaryotic cells to ensure that the genome is precisely duplicated once and only once per cell cycle. This is accomplished by controlling the assembly of a prereplicative complex (pre-RC) which involves the sequential binding to replication origins of the origin recognition complex (ORC), Cdc6/Cdc18, Cdt1, and the minichromosome maintenance complex (Mcm2-Mcm7, or Mcm2-7). Several mechanisms of pre-RC regulation are known, including ATP utilization, cyclin-dependent kinase levels, protein turnover, and Cdt1 binding by geminin. Histone acetylation may also affect the initiation of DNA replication, but at present neither the enzymes nor the steps involved are known. Here, we show that Hbo1, a member of the MYST histone acetyltransferase family, is a previously unrecognized positive regulatory factor for pre-RC assembly. When Hbo1 expression was inhibited in human cells, Mcm2-7 failed to associate with chromatin even though ORC and Cdc6 loading was normal. When Xenopus egg extracts were immunodepleted of Xenopus Hbo1 (XHbo1), chromatin binding of Mcm2-7 was lost, and DNA replication was abolished. The binding of Mcm2-7 to chromatin in XHbo1-depleted extracts could be restored by the addition of recombinant Cdt1.

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Essential role of human CDT1 in DNA replication and chromatin licensing

Journal of Cell Science ◽

10.1242/jcs.115.7.1435 ◽

2002 ◽

Vol 115 (7) ◽

pp. 1435-1440 ◽

Cited By ~ 2

Author(s):

Mickael Rialland ◽

Francesco Sola ◽

Corrado Santocanale

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Complex Formation ◽

Fission Yeast ◽

Origin Recognition Complex ◽

Essential Role ◽

Large Body ◽

Transformed Cells ◽

Minichromosome Maintenance

Formation of pre-replicative complexes at origins is an early cell cycle event essential for DNA duplication. A large body of evidence supports the notion that Cdc6 protein, through its interaction with the origin recognition complex, is required for pre-replicative complex assembly by loading minichromosome maintenance proteins onto DNA. In fission yeast and Xenopus, this reaction known as the licensing of chromatin for DNA replication also requires the newly identified Cdt1 protein. We studied the role of hCdt1 protein in the duplication of the human genome by antibody microinjection experiments and analyzed its expression during the cell cycle in human non-transformed cells. We show that hCdt1 is essential for DNA replication in intact human cells, that it executes its function in a window of the cell cycle overlapping with pre-replicative complex formation and that it is necessary for the loading of minichromosome maintenance proteins onto chromatin. Intriguingly, we observed that hCdt1 protein, in contrast to other licensing factors, is already present in serum-deprived G0 arrested cells and its levels increase only marginally upon re-entry in the cell cycle.

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Visualization of replication initiation and elongation in Drosophila

The Journal of Cell Biology ◽

10.1083/jcb.200207046 ◽

2002 ◽

Vol 159 (2) ◽

pp. 225-236 ◽

Cited By ~ 51

Author(s):

Julie M. Claycomb ◽

David M. MacAlpine ◽

James G. Evans ◽

Stephen P. Bell ◽

Terry L. Orr-Weaver

Keyword(s):

Dna Replication ◽

Origin Recognition Complex ◽

Developmental Stages ◽

Replication Initiation ◽

Nuclear Antigen ◽

Minichromosome Maintenance ◽

Egg Chamber ◽

Two Phases ◽

Replication Factors

Chorion gene amplification in the ovaries of Drosophila melanogaster is a powerful system for the study of metazoan DNA replication in vivo. Using a combination of high-resolution confocal and deconvolution microscopy and quantitative realtime PCR, we found that initiation and elongation occur during separate developmental stages, thus permitting analysis of these two phases of replication in vivo. Bromodeoxyuridine, origin recognition complex, and the elongation factors minichromosome maintenance proteins (MCM)2–7 and proliferating cell nuclear antigen were precisely localized, and the DNA copy number along the third chromosome chorion amplicon was quantified during multiple developmental stages. These studies revealed that initiation takes place during stages 10B and 11 of egg chamber development, whereas only elongation of existing replication forks occurs during egg chamber stages 12 and 13. The ability to distinguish initiation from elongation makes this an outstanding model to decipher the roles of various replication factors during metazoan DNA replication. We utilized this system to demonstrate that the pre–replication complex component, double-parked protein/cell division cycle 10–dependent transcript 1, is not only necessary for proper MCM2–7 localization, but, unexpectedly, is present during elongation.

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Xenopus Cdc7 function is dependent on licensing but not on XORC, XCdc6, or CDK activity and is required for XCdc45 loading

Genes & Development ◽

10.1101/gad.14.12.1528 ◽

2000 ◽

Vol 14 (12) ◽

pp. 1528-1540

Author(s):

Pedro Jares ◽

J. Julian Blow

Keyword(s):

Dna Replication ◽

Origin Recognition Complex ◽

Protein Complexes ◽

Present Report ◽

S Phase ◽

Chromosomal Dna ◽

Minichromosome Maintenance ◽

Initiation Of Replication ◽

Sequential Binding

The assembly and disassembly of protein complexes at replication origins play a crucial role in the regulation of chromosomal DNA replication. The sequential binding of the origin recognition complex (ORC), Cdc6, and the minichromosome maintenance (MCM/P1) proteins produces a licensed replication origin. Before the initiation of replication can occur, each licensed origin must be acted upon by S phase-inducing CDKs and the Cdc7 protein kinase. In the present report we describe the role of Xenopus Cdc7 (XCdc7) in DNA replication using cell-free extracts of Xenopus eggs. We show that XCdc7 binds to chromatin during G1 and S phase. XCdc7 associates with chromatin only once origins have been licensed, but this association does not require the continued presence of XORC or XCdc6 once they have fulfilled their essential role in licensing. Moreover, XCdc7 is required for the subsequent CDK-dependent loading of XCdc45 but is not required for the destabilization of origins that occurs once licensing is complete. Finally, we show that CDK activity is not necessary for XCdc7 to associate with chromatin, induce MCM/P1 phosphorylation, or perform its essential replicative function. From these results we suggest a simple model for the assembly of functional initiation complexes in the Xenopus system.

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Identification of a Preinitiation Step in DNA Replication That Is Independent of Origin Recognition Complex and cdc6, but Dependent on cdk2

The Journal of Cell Biology ◽

10.1083/jcb.140.2.271 ◽

1998 ◽

Vol 140 (2) ◽

pp. 271-281 ◽

Cited By ~ 143

Author(s):

Xuequn Helen Hua ◽

John Newport

Keyword(s):

Dna Replication ◽

Origin Recognition Complex ◽

Minichromosome Maintenance ◽

Cdk2 Activity ◽

Proteolytic Pathway ◽

Egg Extracts ◽

Dna Replication Origin ◽

Initiation Of Dna Replication ◽

Mcm Proteins ◽

Origin Recognition

Before initiation of DNA replication, origin recognition complex (ORC) proteins, cdc6, and minichromosome maintenance (MCM) proteins bind to chromatin sequentially and form preinitiation complexes. Using Xenopus laevis egg extracts, we find that after the formation of these complexes and before initiation of DNA replication, cdc6 is rapidly removed from chromatin, possibly degraded by a cdk2-activated, ubiquitin-dependent proteolytic pathway. If this displacement is inhibited, DNA replication fails to initiate. We also find that after assembly of MCM proteins into preinitiation complexes, removal of the ORC from DNA does not block the subsequent initiation of replication. Importantly, under conditions in which both ORC and cdc6 protein are absent from preinitiation complexes, DNA replication is still dependent on cdk2 activity. Therefore, the final steps in the process leading to initiation of DNA replication during S phase of the cell cycle are independent of ORC and cdc6 proteins, but dependent on cdk2 activity.

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Down-regulation of CK2α correlates with decreased expression levels of DNA replication minichromosome maintenance protein complex (MCM) genes

Scientific Reports ◽

10.1038/s41598-019-51056-5 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Susanne Schaefer ◽

Thomas K. Doktor ◽

Sabrina B. Frederiksen ◽

Kathleen Chea ◽

Mirka Hlavacova ◽

...

Keyword(s):

Gene Expression ◽

Cell Cycle ◽

Cell Proliferation ◽

Dna Replication ◽

Protein Kinase ◽

Protein Kinase Ck2 ◽

Minichromosome Maintenance ◽

Catalytic Subunits ◽

Expression Levels ◽

Kinase Ck2

Abstract Protein kinase CK2 is a serine/threonine kinase composed of two catalytic subunits (CK2α and/or CK2α’) and two regulatory subunits (CK2β). It is implicated in every stage of the cell cycle and in the regulation of various intracellular pathways associated with health and disease states. The catalytic subunits have similar biochemical activity, however, their functions may differ significantly in cells and in vivo. In this regard, homozygous deletion of CK2α leads to embryonic lethality in mid-gestation potentially due to severely impaired cell proliferation. To determine the CK2α-dependent molecular mechanisms that control cell proliferation, we established a myoblast-derived cell line with inducible silencing of CK2α and carried out a comprehensive RNA-Seq analysis of gene expression. We report evidence that CK2α depletion causes delayed cell cycle progression through the S-phase and defective response to replication stress. Differential gene expression analysis revealed that the down-regulated genes were enriched in pathways implicated in cell cycle regulation, DNA replication and DNA damage repair. Interestingly, the genes coding for the minichromosome maintenance proteins (MCMs), which constitute the core of the replication origin recognition complex, were among the most significantly down-regulated genes. These findings were validated in cells and whole mouse embryos. Taken together, our study provides new evidence for a critical role of protein kinase CK2 in controlling DNA replication initiation and the expression levels of replicative DNA helicases, which ensure maintenance of proliferative potential and genome integrity in eukaryotic cells.

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Ciprofloxacin is an inhibitor of the Mcm2-7 replicative helicase

Bioscience Reports ◽

10.1042/bsr20130083 ◽

2013 ◽

Vol 33 (5) ◽

Cited By ~ 21

Author(s):

Nicholas Simon ◽

Matthew L. Bochman ◽

Sandlin Seguin ◽

Jeffrey L. Brodsky ◽

William L. Seibel ◽

...

Keyword(s):

Dna Replication ◽

Dna Helicase ◽

Dna Unwinding ◽

Helicase Activity ◽

Minichromosome Maintenance ◽

Replicative Helicase ◽

Eukaryotic Dna ◽

Minichromosome Maintenance Protein ◽

Ciprofloxacin Resistance

Most currently available small molecule inhibitors of DNA replication lack enzymatic specificity, resulting in deleterious side effects during use in cancer chemotherapy and limited experimental usefulness as mechanistic tools to study DNA replication. Towards development of targeted replication inhibitors, we have focused on Mcm2-7 (minichromosome maintenance protein 2–7), a highly conserved helicase and key regulatory component of eukaryotic DNA replication. Unexpectedly we found that the fluoroquinolone antibiotic ciprofloxacin preferentially inhibits Mcm2-7. Ciprofloxacin blocks the DNA helicase activity of Mcm2-7 at concentrations that have little effect on other tested helicases and prevents the proliferation of both yeast and human cells at concentrations similar to those that inhibit DNA unwinding. Moreover, a previously characterized mcm mutant (mcm4chaos3) exhibits increased ciprofloxacin resistance. To identify more potent Mcm2-7 inhibitors, we screened molecules that are structurally related to ciprofloxacin and identified several that compromise the Mcm2-7 helicase activity at lower concentrations. Our results indicate that ciprofloxacin targets Mcm2-7 in vitro, and support the feasibility of developing specific quinolone-based inhibitors of Mcm2-7 for therapeutic and experimental applications.

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p-Trifluoroacetophenone Oxime Ester Derivatives: Synthesis, Antimicrobial and Cytotoxic Evaluation and Molecular Modeling Studies

Letters in Drug Design & Discovery ◽

10.2174/1570180816666181128112249 ◽

2020 ◽

Vol 17 (2) ◽

pp. 169-183 ◽

Cited By ~ 1

Author(s):

İrem Bozbey ◽

Suat Sari ◽

Emine Şalva ◽

Didem Kart ◽

Arzu Karakurt

Keyword(s):

Molecular Modeling ◽

Neuroblastoma Cell ◽

Neuroblastoma Cells ◽

Cytotoxic Agents ◽

Human Neuroblastoma Cell ◽

Human Neuroblastoma ◽

Modeling Studies ◽

Broth Microdilution Method ◽

Molecular Modeling Studies

Background: Azole antifungals are among the first-line drugs clinically used for the treatment of systemic candidiasis, a deadly type of fungal infection that threatens mostly immunecompromised and hospitalized patients. Some azole derivatives were also reported to have antiproliferative effects on cancer cells. Objective: In this study, 1-(4-trifluoromethylphenyl)-2-(1H-imidazol-1-yl)ethanone (3), its oxime (4), and a series of its novel oxime ester derivatives (5a-v) were synthesized and tested for their in vitro antimicrobial activities against certain ATCC standard strains of Candida sp. fungi and bacteria. The compounds were also tested for their cytotoxic effects against mouse fibroblast and human neuroblastoma cell lines. Molecular modeling studies were performed to provide insights into their possible mechanisms for antifungal and antibacterial actions. Methods: The compounds were synthesized by the reaction of various oximes with acyl chlorides. Antimicrobial activity of the compounds was determined according to the broth microdilution method. For the determination of cytotoxic effect, we used MTS assay. Molecular docking and QM/MM studies were performed to predict the binding mechanisms of the active compounds in the catalytic site of C. albicans CYP51 (CACYP51) and S. aureus flavohemoglobin (SAFH), the latter of which was created via homology modeling. Results: 5d, 5l, and 5t showed moderate antifungal activity against C. albicans, while 3, 5c, and 5r showed significant antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Most of the compounds showed approximately 40-50% inhibition against the human neuroblastoma cells at 100 µM. In this line, 3 was the most potent with an IC50 value of 82.18 μM followed by 5a, 5o, and 5t. 3 and 5a were highly selective to the neuroblastoma cells. Molecular modelling results supported the hypothesis that our compounds were inhibitors of CAYP51 and SAFH. Conclusion: This study supports that oxime ester derivatives may be used for the development of new antimicrobial and cytotoxic agents.

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Plasticity in Neuroblastoma Cell Identity Defines a Noradrenergic-to-Mesenchymal Transition (NMT)

Cancers ◽

10.3390/cancers13122904 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2904

Author(s):

Margot Gautier ◽

Cécile Thirant ◽

Olivier Delattre ◽

Isabelle Janoueix-Lerosey

Keyword(s):

Epithelial To Mesenchymal Transition ◽

Neuroblastoma Cell ◽

Neuroblastoma Cells ◽

Biochemical Properties ◽

Poor Overall Survival ◽

Cell Identity ◽

Mesenchymal Transition ◽

Neuroblastoma Cell Lines

Neuroblastoma, a pediatric cancer of the peripheral sympathetic nervous system, is characterized by an important clinical heterogeneity, and high-risk tumors are associated with a poor overall survival. Neuroblastoma cells may present with diverse morphological and biochemical properties in vitro, and seminal observations suggested that interconversion between two phenotypes called N-type and S-type may occur. In 2017, two main studies provided novel insights into these subtypes through the characterization of the transcriptomic and epigenetic landscapes of a panel of neuroblastoma cell lines. In this review, we focus on the available data that define neuroblastoma cell identity and propose to use the term noradrenergic (NOR) and mesenchymal (MES) to refer to these identities. We also address the question of transdifferentiation between both states and suggest that the plasticity between the NOR identity and the MES identity defines a noradrenergic-to-mesenchymal transition, reminiscent of but different from the well-established epithelial-to-mesenchymal transition.

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Regulation of c-myb expression in human neuroblastoma cells during retinoic acid-induced differentiation.

Molecular and Cellular Biology ◽

10.1128/mcb.8.4.1677 ◽

1988 ◽

Vol 8 (4) ◽

pp. 1677-1683 ◽

Cited By ~ 54

Author(s):

C J Thiele ◽

P S Cohen ◽

M A Israel

Keyword(s):

Retinoic Acid ◽

Fetal Development ◽

Neuroblastoma Cell ◽

Neuroblastoma Cells ◽

Human Neuroblastoma Cell ◽

Human Neuroblastoma Cells ◽

Human Neuroblastoma ◽

Hematopoietic Lineage ◽

Specific Manner ◽

Neuroblastoma Cell Lines

We detected expression of the c-myb proto-oncogene, which was initially thought to be expressed in a tissue-specific manner in cells of hematopoietic lineage, in human tissues of neuronal origin. Since the level of c-myb expression declined during fetal development, we studied the regulation of its expression in human neuroblastoma cell lines induced to differentiate by retinoic acid. The expression of c-myb declined during the maturation of neuroblastoma cells, and this change was mediated by a decrease in c-myb transcription.

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