Cyclin-Dependent Kinase 5 Decreases in Gastric Cancer and Its
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Restoring MLL Reactivates Latent Tumor Suppression-Mediated Vulnerability to Proteasome Inhibitors
Oncogene (2020) 39:5888–5901 https://doi.org/10.1038/s41388-020-01408-7 ARTICLE Restoring MLL reactivates latent tumor suppression-mediated vulnerability to proteasome inhibitors 1 1 2 1 3 1 4 2 Maolin Ge ● Dan Li ● Zhi Qiao ● Yan Sun ● Ting Kang ● Shouhai Zhu ● Shifen Wang ● Hua Xiao ● 1 5 4 1 Chunjun Zhao ● Shuhong Shen ● Zhenshu Xu ● Han Liu Received: 12 March 2020 / Revised: 16 July 2020 / Accepted: 23 July 2020 / Published online: 30 July 2020 © The Author(s) 2020. This article is published with open access Abstract MLL undergoes multiple distinct chromosomal translocations to yield aggressive leukemia with dismal outcomes. Besides their well-established role in leukemogenesis, MLL fusions also possess latent tumor-suppressive activity, which can be exploited as effective cancer treatment strategies using pharmacological means such as proteasome inhibitors (PIs). Here, using MLL-rearranged xenografts and MLL leukemic cells as models, we show that wild-type MLL is indispensable for the latent tumor-suppressive activity of MLL fusions. MLL dysfunction, shown as loss of the chromatin accumulation and subsequent degradation of MLL, compromises the latent tumor suppression of MLL-AF4 and is instrumental for the 1234567890();,: 1234567890();,: acquired PI resistance. Mechanistically, MLL dysfunction is caused by chronic PI treatment-induced epigenetic reprogramming through the H2Bub-ASH2L-MLL axis and can be specifically restored by histone deacetylase (HDAC) inhibitors, which induce histone acetylation and recruits MLL on chromatin to promote cell cycle gene expression. Our findings not only demonstrate the mechanism underlying the inevitable acquisition of PI resistance in MLL leukemic cells, but also illustrate that preventing the emergence of PI-resistant cells constitutes a novel rationale for combination therapy with PIs and HDAC inhibitors in MLL leukemias. -
DNA Damage Checkpoint Dynamics Drive Cell Cycle Phase Transitions
bioRxiv preprint doi: https://doi.org/10.1101/137307; this version posted August 4, 2017. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. DNA damage checkpoint dynamics drive cell cycle phase transitions Hui Xiao Chao1,2, Cere E. Poovey1, Ashley A. Privette1, Gavin D. Grant3,4, Hui Yan Chao1, Jeanette G. Cook3,4, and Jeremy E. Purvis1,2,4,† 1Department of Genetics 2Curriculum for Bioinformatics and Computational Biology 3Department of Biochemistry and Biophysics 4Lineberger Comprehensive Cancer Center University of North Carolina, Chapel Hill 120 Mason Farm Road Chapel Hill, NC 27599-7264 †Corresponding Author: Jeremy Purvis Genetic Medicine Building 5061, CB#7264 120 Mason Farm Road Chapel Hill, NC 27599-7264 [email protected] ABSTRACT DNA damage checkpoints are cellular mechanisms that protect the integrity of the genome during cell cycle progression. In response to genotoxic stress, these checkpoints halt cell cycle progression until the damage is repaired, allowing cells enough time to recover from damage before resuming normal proliferation. Here, we investigate the temporal dynamics of DNA damage checkpoints in individual proliferating cells by observing cell cycle phase transitions following acute DNA damage. We find that in gap phases (G1 and G2), DNA damage triggers an abrupt halt to cell cycle progression in which the duration of arrest correlates with the severity of damage. However, cells that have already progressed beyond a proposed “commitment point” within a given cell cycle phase readily transition to the next phase, revealing a relaxation of checkpoint stringency during later stages of certain cell cycle phases. -
Cyclin-Dependent Kinases and P53 Pathways Are Activated Independently and Mediate Bax Activation in Neurons After DNA Damage
The Journal of Neuroscience, July 15, 2001, 21(14):5017–5026 Cyclin-Dependent Kinases and P53 Pathways Are Activated Independently and Mediate Bax Activation in Neurons after DNA Damage Erick J. Morris,1 Elizabeth Keramaris,2 Hardy J. Rideout,3 Ruth S. Slack,2 Nicholas J. Dyson,1 Leonidas Stefanis,3 and David S. Park2 1Massachusetts General Hospital Cancer Center, Laboratory of Molecular Oncology, Charlestown, Massachusetts 02129, 2Neuroscience Research Institute, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada, and 3Columbia University, New York, New York 10032 DNA damage has been implicated as one important initiator of ization, and DNA binding that result from DNA damage are not cell death in neuropathological conditions such as stroke. Ac- affected by the inhibition of CDK activity. Conversely, no de- cordingly, it is important to understand the signaling processes crease in retinoblastoma protein (pRb) phosphorylation was that control neuronal death induced by this stimulus. Previous observed in p53-deficient neurons that were treated with camp- evidence has shown that the death of embryonic cortical neu- tothecin. However, either p53 deficiency or the inhibition of rons treated with the DNA-damaging agent camptothecin is CDK activity alone inhibited Bax translocation, cytochrome c dependent on the tumor suppressor p53 and cyclin-dependent release, and caspase-3-like activation. Taken together, our re- kinase (CDK) activity and that the inhibition of either pathway sults indicate that p53 and CDK are activated independently alone leads to enhanced and prolonged survival. We presently and then act in concert to control Bax-mediated apoptosis. show that p53 and CDKs are activated independently on par- allel pathways. -
Mitosis Vs. Meiosis
Mitosis vs. Meiosis In order for organisms to continue growing and/or replace cells that are dead or beyond repair, cells must replicate, or make identical copies of themselves. In order to do this and maintain the proper number of chromosomes, the cells of eukaryotes must undergo mitosis to divide up their DNA. The dividing of the DNA ensures that both the “old” cell (parent cell) and the “new” cells (daughter cells) have the same genetic makeup and both will be diploid, or containing the same number of chromosomes as the parent cell. For reproduction of an organism to occur, the original parent cell will undergo Meiosis to create 4 new daughter cells with a slightly different genetic makeup in order to ensure genetic diversity when fertilization occurs. The four daughter cells will be haploid, or containing half the number of chromosomes as the parent cell. The difference between the two processes is that mitosis occurs in non-reproductive cells, or somatic cells, and meiosis occurs in the cells that participate in sexual reproduction, or germ cells. The Somatic Cell Cycle (Mitosis) The somatic cell cycle consists of 3 phases: interphase, m phase, and cytokinesis. 1. Interphase: Interphase is considered the non-dividing phase of the cell cycle. It is not a part of the actual process of mitosis, but it readies the cell for mitosis. It is made up of 3 sub-phases: • G1 Phase: In G1, the cell is growing. In most organisms, the majority of the cell’s life span is spent in G1. • S Phase: In each human somatic cell, there are 23 pairs of chromosomes; one chromosome comes from the mother and one comes from the father. -
Caspase-Dependent Activation of Cyclin-Dependent Kinases During Fas-Induced Apoptosis in Jurkat Cells
Proc. Natl. Acad. Sci. USA Vol. 95, pp. 6785–6790, June 1998 Cell Biology Caspase-dependent activation of cyclin-dependent kinases during Fas-induced apoptosis in Jurkat cells BIN-BING ZHOU,HONGLIN LI,JUNYING YUAN, AND MARC W. KIRSCHNER Department of Cell Biology, Harvard Medical School, Boston, MA 02115 Contributed by Marc W. Kirschner, April 7, 1998 ABSTRACT The activation of cyclin-dependent kinases To study the mechanism of cdc2 and cdk2 activation in (cdks) has been implicated in apoptosis induced by various apoptotic cells, we examined cyclin synthesis, cyclin degrada- stimuli. We find that the Fas-induced activation of cdc2 and tion, and posttranslational modifications of cdc2 and cdk2 cdk2 in Jurkat cells is not dependent on protein synthesis, during Fas-induced apoptosis in Jurkat cells. We find that Fas which is shut down very early during apoptosis before induction activates cdc2 and cdk2, despite a potential loss of caspase-3 activation. Instead, activation of these kinases these proteins caused by the very rapid drop in the capacity for seems to result from both a rapid cleavage of Wee1 (an protein synthesis. Activation of these kinases seems to result inhibitory kinase of cdc2 and cdk2) and inactivation of from the maintenance of cyclin levels by rapid inactivation of anaphase-promoting complex (the specific system for cyclin APC, through a caspase-dependent cleavage of one of its degradation), in which CDC27 homolog is cleaved during subunits, and tyrosine dephosphorylation of cdks caused by a apoptosis. Both Wee1 and CDC27 are shown to be substrates cleavage of the inhibitory kinase Wee1. -
Epithelial Cell Death Analysis of Cell Cycle by Flow Cytometry White Paper
Epithelial Cell Death Analysis of Cell Cycle by Flow Cytometry White Paper Authors: Savithri Balasubramanian, John Tigges, Vasilis Toxavidis, Heidi Mariani. Affiliation: Beth Israel Deaconess Medical Center Harvard Stem Cell Institute a Beckman Coulter Life Sciences: Epithelial Cell Death Analysis of Cell Cycle by Flow Cytometry PRINCIPAL OF TECHNIQUE Background: Cell cycle, or cell-division cycle, is the series of events that takes place in a cell leading to its division and duplication (replication). In cells without a nucleus (prokaryotic), cell cycle occurs via a process termed binary fission. In cells with a nucleus (eukaryotes), cell cycle can be divided in two brief periods: interphase—during which the cell grows, accumulating nutrients needed for mitosis and duplicating its DNA—and the mitosis (M) phase, during which the cell splits itself into two distinct cells, often called «daughter cells». Cell-division cycle is a vital process by which a single-celled fertilized egg develops into a mature organism, as well as the process by which hair, skin, blood cells, and some internal organs are renewed. Cell cycle consists of four distinct phases: G1 phase, S phase (synthesis), G2 phase (collectively known as interphase) and M phase (mitosis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell’s chromosomes are divided between the two daughter cells, and cytokinesis, in which the cell’s cytoplasm divides in half forming distinct cells. Activation of each phase is dependent on the proper progression and completion of the previous one. Cells that have temporarily or reversibly stopped dividing are said to have entered a state of quiescence called G0 phase. -
Transcriptional Regulation of the P16 Tumor Suppressor Gene
ANTICANCER RESEARCH 35: 4397-4402 (2015) Review Transcriptional Regulation of the p16 Tumor Suppressor Gene YOJIRO KOTAKE, MADOKA NAEMURA, CHIHIRO MURASAKI, YASUTOSHI INOUE and HARUNA OKAMOTO Department of Biological and Environmental Chemistry, Faculty of Humanity-Oriented Science and Engineering, Kinki University, Fukuoka, Japan Abstract. The p16 tumor suppressor gene encodes a specifically bind to and inhibit the activity of cyclin-CDK specific inhibitor of cyclin-dependent kinase (CDK) 4 and 6 complexes, thus preventing G1-to-S progression (4, 5). and is found altered in a wide range of human cancers. p16 Among these CKIs, p16 plays a pivotal role in the regulation plays a pivotal role in tumor suppressor networks through of cellular senescence through inhibition of CDK4/6 activity inducing cellular senescence that acts as a barrier to (6, 7). Cellular senescence acts as a barrier to oncogenic cellular transformation by oncogenic signals. p16 protein is transformation induced by oncogenic signals, such as relatively stable and its expression is primary regulated by activating RAS mutations, and is achieved by accumulation transcriptional control. Polycomb group (PcG) proteins of p16 (Figure 1) (8-10). The loss of p16 function is, associate with the p16 locus in a long non-coding RNA, therefore, thought to lead to carcinogenesis. Indeed, many ANRIL-dependent manner, leading to repression of p16 studies have shown that the p16 gene is frequently mutated transcription. YB1, a transcription factor, also represses the or silenced in various human cancers (11-14). p16 transcription through direct association with its Although many studies have led to a deeper understanding promoter region. -
Kinetochores, Microtubules, and Spindle Assembly Checkpoint
Review Joined at the hip: kinetochores, microtubules, and spindle assembly checkpoint signaling 1 1,2,3 Carlos Sacristan and Geert J.P.L. Kops 1 Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands 2 Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands 3 Cancer Genomics Netherlands, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands Error-free chromosome segregation relies on stable and cell division. The messenger is the SAC (also known as connections between kinetochores and spindle microtu- the mitotic checkpoint) (Figure 1). bules. The spindle assembly checkpoint (SAC) monitors The transition to anaphase is triggered by the E3 ubiqui- such connections and relays their absence to the cell tin ligase APC/C, which tags inhibitors of mitotic exit cycle machinery to delay cell division. The molecular (CYCLIN B) and of sister chromatid disjunction (SECURIN) network at kinetochores that is responsible for microtu- for proteasomal degradation [2]. The SAC has a one-track bule binding is integrated with the core components mind, inhibiting APC/C as long as incorrectly attached of the SAC signaling system. Molecular-mechanistic chromosomes persist. It goes about this in the most straight- understanding of how the SAC is coupled to the kineto- forward way possible: it assembles a direct and diffusible chore–microtubule interface has advanced significantly inhibitor of APC/C at kinetochores that are not connected in recent years. The latest insights not only provide a to spindle microtubules. This inhibitor is named the striking view of the dynamics and regulation of SAC mitotic checkpoint complex (MCC) (Figure 1). -
P14arf Induces G2 Arrest and Apoptosis Independently of P53
Oncogene (2003) 22, 1822–1835 & 2003 Nature Publishing Group All rights reserved 0950-9232/03 $25.00 www.nature.com/onc ARF p14 induces G2 arrest and apoptosis independently of p53 leading to regression of tumours established in nude mice Be´ atrice Eymin, Camille Leduc, Jean-Luc Coll, Elisabeth Brambilla and Sylvie Gazzeri Groupe de Recherche sur le Cancer du Poumon, EA 2021, Equipe INSERM 9924, Institut Albert Bonniot, 38706 La Tronche Cedex, France Until recently, the ability of ARF (human p14ARF, murine kinases (Serrano et al., 1993). On the other hand, ARF p19ARF) tumour-suppressor protein, encoded by the protects against cellular transformation and immortali- INK4A/ARF locus, to inhibit cell growth in response to zation by activating the p53tumour suppressive protein various stimuli was related to its ability to stabilize p53 (Sherr, 1998). Expression of ARF is induced in response through the so-called ARF/MDM2/p53 pathway. How- to activated oncogenes such as Ras (Serrano et al., 1997; ever, recent data have demonstrated that ARF is not Palmero et al., 1998), c-myc (Zindy et al., 1998), E1A (de implicated in this unique p53-dependent pathway. By use Stanchina et al., 1998), Abl (Radfar et al., 1998; Cong of transient and stable expression, we show here that et al., 1999) and E2F-1 (Bates et al., 1998; Dimri et al., human p14ARF inhibits the growth of human tumoral cells 2000) as well as during replicative senescence (Sherr, lacking functional p53 by inducing a transient G2 arrest 1998). Since ARF-null mice are highly tumour prone ARF and subsequently apoptosis. -
The P16 Status of Tumor Cell Lines Identifies Small Molecule Inhibitors Specific for Cyclin-Dependent Kinase 41
Vol. 5, 4279–4286, December 1999 Clinical Cancer Research 4279 The p16 Status of Tumor Cell Lines Identifies Small Molecule Inhibitors Specific for Cyclin-dependent Kinase 41 Akihito Kubo,2 Kazuhiko Nakagawa,2, 3 CDK4 kinase inhibitors that may selectively induce growth Ravi K. Varma, Nicholas K. Conrad, inhibition of p16-altered tumors. Jin Quan Cheng, Wen-Ching Lee, INTRODUCTION Joseph R. Testa, Bruce E. Johnson, INK4A 4 The p16 gene (also known as CDKN2A) encodes p16 , Frederic J. Kaye, and Michael J. Kelley which inhibits the CDK45:cyclin D and CDK6:cyclin D com- Medicine Branch [A. K., K. N., N. K. C., F. J. K., B. E. J.] and plexes (1). These complexes mediate phosphorylation of the Rb Developmental Therapeutics Program [R. K. V.], National Cancer Institute, Bethesda, Maryland 20889; Department of Medical protein and allow cell cycle progression beyond the G1-S-phase Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania checkpoint (2). Alterations of p16 have been described in a wide 19111 [J. Q. C., W-C. L., J. R. T.]; and Department of Medicine, variety of histological types of human cancers including astro- Duke University Medical Center, Durham, North Carolina 27710 cytoma, melanoma, leukemia, breast cancer, head and neck [M. J. K.] squamous cell carcinoma, malignant mesothelioma, and lung cancer. Alterations of p16 can occur through homozygous de- ABSTRACT letion, point mutation, and transcriptional suppression associ- ated with hypermethylation in cancer cell lines and primary Loss of p16 functional activity leading to disruption of tumors (reviewed in Refs. 3–5). the p16/cyclin-dependent kinase (CDK) 4:cyclin D/retino- Whereas the Rb gene is inactivated in a narrow range of blastoma pathway is the most common event in human tumor cells, the pattern of mutational inactivation of Rb is tumorigenesis, suggesting that compounds with CDK4 ki- inversely correlated with p16 alterations (6–8), suggesting that nase inhibitory activity may be useful to regulate cancer cell a single defect in the p16/CDK4:cyclin D/Rb pathway is suffi- growth. -
Cyclin E-CDK2 Is a Regulator of P27 Kip1
Downloaded from genesdev.cshlp.org on October 4, 2021 - Published by Cold Spring Harbor Laboratory Press Cyclin E-CDK2 is a regulator of p27 Kip1 Robert J. Sheaff, 1 Mark Groudine, 1'4 Matthew Gordon, 1 James M. Roberts, 1's and Bruce E. Clurman 1-3,5 Divisions of 1Basic Sciences and 2Clinical Research, Fred Hutchinson Cancer Research Center (FHCRC), Seattle, Washington 98104; Departments of 3Medicine and 4Radiation Oncology, University of Washington, Seattle, Washington 98104 CDK inhibitors are thought to prevent cell proliferation by negatively regulating cyclin-CDK complexes. We propose that the opposite is also true, that cyclin-CDK complexes in mammmalian cells can promote cell cycle progression by directly down-regulating CDK inhibitors. We show that expression of cyclin E-CDK2 in murine fibroblasts causes phosphorylation of the CDK inhibitor p27 Kip1 on T187, and that cyclin E-CDK2 can directly phosphorylate p27 T187 in vitro. We further show that cyclin E-CDK2-dependent phosphorylation of p27 results in elimination of p27 from the cell, allowing cells to transit from G1 to S phase. Moreover, mutation of T187 in p27 to alanine creates a p27 protein that causes a G1 block resistant to cyclin E and whose level of expression is not modulated by cyclin E. A kinetic analysis of the interaction between p27 and cyclin E-CDK2 explains how p27 can be regulated by the same enzyme it targets for inhibition. We show that p27 interacts with cyclin E-CDK2 in at least two distinct ways: one resulting in p27 phosphorylation and release, the other in tight binding and cyclin E-CDK2 inhibition. -
The Cell Cycle & Mitosis
The Cell Cycle & Mitosis Cell Growth The Cell Cycle is G1 phase ___________________________________ _______________________________ During the Cell Cycle, a cell ___________________________________ ___________________________________ Anaphase Cell Division ___________________________________ Mitosis M phase M ___________________________________ S phase replication DNA Interphase Interphase is ___________________________ ___________________________________ G2 phase Interphase is divided into three phases: ___, ___, & ___ G1 Phase S Phase G2 Phase The G1 phase is a period of The S phase replicates During the G2 phase, many of activity in which cells _______ ________________and the organelles and molecules ____________________ synthesizes _______ molecules. required for ____________ __________ Cells will When DNA replication is ___________________ _______________ and completed, _____________ When G2 is completed, the cell is synthesize new ___________ ____________________ ready to enter the ____________________ ____________________ ____________________ ____________________ ____________________ Mitosis are divided into four phases: _____________, ______________, _____________, & _____________ Below are cells in two different phases of the cell cycle, fill in the blanks using the word bank: Chromatin Nuclear Envelope Chromosome Sister Chromatids Nucleolus Spinder Fiber Centrosome Centrioles 5.._________ 1.__________ v 6..__________ 2.__________ 7.__________ 3.__________ 8..__________ 4.__________ v The Cell Cycle & Mitosis Microscope Lab: