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Schütz M, Wangen C, Sommerer M, Kögler M, Eickhoff J, Degenhart C, Klebl B, Naing Z, Egilmezer E, Hamilton ST, Rawlinson WD, Sticht H, Marschall M. Cytomegalovirus cyclin-dependent kinase ortholog vCDK/pUL97 undergoes regulatory interaction with human cyclin H and CDK7 to codetermine viral replication efficiency. Virus Res 2023; 335:199200. [PMID: 37591314 PMCID: PMC10445456 DOI: 10.1016/j.virusres.2023.199200] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 08/19/2023]
Abstract
Human cytomegalovirus (HCMV) infection is shaped by a tightly regulated interplay between viral and cellular proteins. Distinct kinase activities, such as the viral cyclin-dependent kinase ortholog (vCDK) pUL97 and cellular CDK7 are both crucial for efficient viral replication. Previously, we reported that both kinases, vCDK/pUL97 and CDK7, interact with cyclin H, thereby achieving an enhanced level of kinase activity and overall functionality in viral replication. Here we provide a variety of novel results, as generated on a methodologically extended basis, and present a concept for the codetermination of viral replication efficiency through these kinase activities: (i) cyclin H expression, in various human cell types, is substantially upregulated by strains of HCMV including the clinically relevant HCMV Merlin; (ii) vCDK/pUL97 interacts with human cyclin H in both HCMV-infected and plasmid-transfected cell systems; (iii) a doxycycline-inducible shRNA-dependent knock-down (KD) of cyclin H significantly reduces pUL97 activity (qSox in vitro kinase assay); (iv) accordingly, pUL97 in vitro kinase activity is seen significantly increased upon addition of recombinant cyclin H; (v) as a point of specific importance, human CDK7 activity shows an increase by vCDK/pUL97-mediated trans-stimulation (whereas pUL97 is not stimulated by CDK7); (vi) phosphosite-specific antibodies indicate an upregulated CDK7 phosphorylation upon HCMV infection, as mediated through a pUL97-specific modulatory effect (i.e. shown by pUL97 inhibitor treatment or pUL97-deficient viral mutant); (vii) finally, an efficient KD of cyclin H in primary fibroblasts generally results in an impaired HCMV replication efficiency as measured on protein and genomic levels. These results show evidence for the codetermination of viral replication by vCDK/pUL97, cyclin H and CDK7, thus supporting the specific importance of cyclin H as a central regulatory factor, and suggesting novel targeting options for antiviral drugs.
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Affiliation(s)
- Martin Schütz
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany.
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | - Mona Sommerer
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | - Melanie Kögler
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | | | | | - Bert Klebl
- Lead Discovery Center GmbH, Dortmund, Germany
| | - Zin Naing
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Ece Egilmezer
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Stuart T Hamilton
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - William D Rawlinson
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, FAU, Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany.
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Rabaglino MB, Salilew-Wondim D, Zolini A, Tesfaye D, Hoelker M, Lonergan P, Hansen PJ. Machine-learning methods applied to integrated transcriptomic data from bovine blastocysts and elongating conceptuses to identify genes predictive of embryonic competence. FASEB J 2023; 37:e22809. [PMID: 36753406 DOI: 10.1096/fj.202201977r] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 01/13/2023] [Accepted: 01/26/2023] [Indexed: 02/09/2023]
Abstract
Early pregnancy loss markedly impacts reproductive efficiency in cattle. The objectives were to model a biologically relevant gene signature predicting embryonic competence for survival after integrating transcriptomic data from blastocysts and elongating conceptuses with different developmental capacities and to validate the potential biomarkers with independent embryonic data sets through the application of machine-learning algorithms. First, two data sets from in vivo-produced blastocysts competent or not to sustain a pregnancy were integrated with a data set from long and short day-15 conceptuses. A statistical contrast determined differentially expressed genes (DEG) increasing in expression from a competent blastocyst to a long conceptus and vice versa; these were enriched for KEGG pathways related to glycolysis/gluconeogenesis and RNA processing, respectively. Next, the most discriminative DEG between blastocysts that resulted or did not in pregnancy were selected by linear discriminant analysis. These eight putative biomarker genes were validated by modeling their expression in competent or noncompetent blastocysts through Bayesian logistic regression or neural networks and predicting embryo developmental fate in four external data sets consisting of in vitro-produced blastocysts (i) competent or not, or (ii) exposed or not to detrimental conditions during culture, and elongated conceptuses (iii) of different length, or (iv) developed in the uteri of high- or subfertile heifers. Predictions for each data set were more than 85% accurate, suggesting that these genes play a key role in embryo development and pregnancy establishment. In conclusion, this study integrated transcriptomic data from seven independent experiments to identify a small set of genes capable of predicting embryonic competence for survival.
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Affiliation(s)
- Maria Belen Rabaglino
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Ireland
| | - Dessie Salilew-Wondim
- Institute of Animal Sciences, Animal Breeding, University of Bonn, Bonn, Germany.,Department of Animal Science, Biotechnology & Reproduction in Farm Animals, University of Goettingen, Goettingen, Germany
| | - Adriana Zolini
- Department of Animal Sciences, D.H. Barron Reproductive and Perinatal Biology Research Program, and Genetics Institute, University of Florida, Gainesville, Florida, USA
| | - Dawit Tesfaye
- Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Michael Hoelker
- Department of Animal Science, Biotechnology & Reproduction in Farm Animals, University of Goettingen, Goettingen, Germany
| | - Pat Lonergan
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Ireland
| | - Peter J Hansen
- Department of Animal Sciences, D.H. Barron Reproductive and Perinatal Biology Research Program, and Genetics Institute, University of Florida, Gainesville, Florida, USA
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3
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Attia YM, Salama SA, Shouman SA, Ivan C, Elsayed AM, Amero P, Rodriguez-Aguayo C, Lopez-Berestein G. Targeting CDK7 reverses tamoxifen resistance through regulating stemness in ER+ breast cancer. Pharmacol Rep 2022; 74:366-378. [PMID: 35000145 DOI: 10.1007/s43440-021-00346-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 11/24/2021] [Accepted: 11/28/2021] [Indexed: 12/24/2022]
Abstract
BACKGROUND Although tamoxifen is the mainstay endocrine therapy for estrogen receptor-positive (ER+) breast cancer patients, the emergence of tamoxifen resistance is still the major challenge that results in treatment failure. Tamoxifen is very effective in halting breast cancer cell proliferation; nonetheless, the ability of tamoxifen to target cancer stem and progenitor cell populations (CSCs), a major key player for the emergence of tamoxifen resistance, has not been adequately investigated yet. Thus, we explored whether targeting CDK7 modulates CSCs subpopulation and tamoxifen resistance in ER+ breast cancer cells. METHODS Mammosphere-formation assay, stem cell biomarkers and tamoxifen sensitivity were analyzed in MCF7 tamoxifen-sensitive cell line and its resistant counterpart, LCC2, following CDK7 targeting by THZ1 or siRNA. RESULTS Analysis of clinically relevant data indicated that expression of stemness factor, SOX2, was positively correlated with CDK7 expression in tamoxifen-treated patients. Moreover, overexpression of the stemness gene, SOX2, was associated with shorter overall survival in those patients. Importantly, the number of CSC populations and the expression of CDK7, P-Ser118-ER-α and c-MYC were significantly higher in LCC2 cells compared with parental MCF-7 cells. Moreover, targeting CDK7 inhibited mammosphere formation, CSC-regulating genes, and CSC biomarkers expression in MCF-7 and LCC2 cells. CONCLUSION Our data indicate, for the first time, that CDK7-targeted therapy in ER+ breast cancer ameliorates tamoxifen resistance, at least in part, by inhibiting cancer stemness. Thus, targeting CDK7 might represent a potential approach for relieving tamoxifen resistance in ER+ breast cancer.
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Affiliation(s)
- Yasmin M Attia
- Pharmacology and Experimental Therapeutics Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Kasr Al Eini Street, Fom El Khalig, Cairo, 11796, Egypt. .,Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.
| | - Salama A Salama
- Pharmacology and Toxicology Department, Faculty of Pharmacy, Al-Azhar University, Cairo, 11651, Egypt.
| | - Samia A Shouman
- Pharmacology and Experimental Therapeutics Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Kasr Al Eini Street, Fom El Khalig, Cairo, 11796, Egypt
| | - Cristina Ivan
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,Center for RNA Interference and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Abdelrahman M Elsayed
- Pharmacology and Toxicology Department, Faculty of Pharmacy, Al-Azhar University, Cairo, 11651, Egypt.,Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Paola Amero
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Cristian Rodriguez-Aguayo
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,Center for RNA Interference and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Gabriel Lopez-Berestein
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,Center for RNA Interference and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
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TGF-β/activin signaling promotes CDK7 inhibitor resistance in triple-negative breast cancer cells through upregulation of multidrug transporters. J Biol Chem 2021; 297:101162. [PMID: 34481843 PMCID: PMC8498470 DOI: 10.1016/j.jbc.2021.101162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 08/23/2021] [Accepted: 08/31/2021] [Indexed: 01/10/2023] Open
Abstract
Cyclin-dependent kinase 7 (CDK7) is a master regulatory kinase that drives cell cycle progression and stimulates expression of oncogenes in a myriad of cancers. Inhibitors of CDK7 (CDK7i) are currently in clinical trials; however, as with many cancer therapies, patients will most likely experience recurrent disease due to acquired resistance. Identifying targets underlying CDK7i resistance will facilitate prospective development of new therapies that can circumvent such resistance. Here we utilized triple-negative breast cancer as a model to discern mechanisms of resistance as it has been previously shown to be highly responsive to CDK7 inhibitors. After generating cell lines with acquired resistance, high-throughput RNA sequencing revealed significant upregulation of genes associated with efflux pumps and transforming growth factor-beta (TGF-β) signaling pathways. Genetic silencing or pharmacological inhibition of ABCG2, an efflux pump associated with multidrug resistance, resensitized resistant cells to CDK7i, indicating a reliance on these transporters. Expression of activin A (INHBA), a member of the TGF-β family of ligands, was also induced, whereas its intrinsic inhibitor, follistatin (FST), was repressed. In resistant cells, increased phosphorylation of SMAD3, a downstream mediator, confirmed an increase in activin signaling, and phosphorylated SMAD3 directly bound the ABCG2 promoter regulatory region. Finally, pharmacological inhibition of TGF-β/activin receptors or genetic silencing of SMAD4, a transcriptional partner of SMAD3, reversed the upregulation of ABCG2 in resistant cells and phenocopied ABCG2 inhibition. This study reveals that inhibiting the TGF-β/Activin-ABCG2 pathway is a potential avenue for preventing or overcoming resistance to CDK7 inhibitors.
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5
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Decker TM. Mechanisms of Transcription Elongation Factor DSIF (Spt4-Spt5). J Mol Biol 2020; 433:166657. [PMID: 32987031 DOI: 10.1016/j.jmb.2020.09.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/16/2020] [Accepted: 09/20/2020] [Indexed: 12/19/2022]
Abstract
The transcription elongation factor Spt5 is conserved from bacteria to humans. In eukaryotes, Spt5 forms a complex with Spt4 and regulates processive transcription elongation. Recent studies on transcription elongation suggest different mechanistic roles in yeast versus mammals. Higher eukaryotes utilize Spt4-Spt5 (DSIF) to regulate promoter-proximal pausing, a transcription-regulatory mechanism that connects initiation to productive elongation. DSIF is a versatile transcription factor and has been implicated in both gene-specific regulation and transcription through nucleosomes. Future studies will further elucidate the role of DSIF in transcriptional dynamics and disentangle its inhibitory and enhancing activities in transcription.
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Affiliation(s)
- Tim-Michael Decker
- Department of Biochemistry, University of Colorado, 3415 Colorado Ave, Boulder, CO 80303, USA.
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Iacobas DA, Iacobas S, Stout RF, Spray DC. Cellular Environment Remodels the Genomic Fabrics of Functional Pathways in Astrocytes. Genes (Basel) 2020; 11:genes11050520. [PMID: 32392822 PMCID: PMC7290327 DOI: 10.3390/genes11050520] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/27/2020] [Accepted: 05/04/2020] [Indexed: 02/06/2023] Open
Abstract
We profiled the transcriptomes of primary mouse cortical astrocytes cultured alone or co-cultured with immortalized precursor oligodendrocytes (Oli-neu cells). Filters between the cell types prevented formation of hetero-cellular gap junction channels but allowed for free exchange of the two culture media. We previously reported that major functional pathways in the Oli-neu cells are remodeled by the proximity of non-touching astrocytes and that astrocytes and oligodendrocytes form a panglial transcriptomic syncytium in the brain. Here, we present evidence that the astrocyte transcriptome likewise changes significantly in the proximity of non-touching Oli-neu cells. Our results indicate that the cellular environment strongly modulates the transcriptome of each cell type and that integration in a heterocellular tissue changes not only the expression profile but also the expression control and networking of the genes in each cell phenotype. The significant decrease of the overall transcription control suggests that in the co-culture astrocytes are closer to their normal conditions from the brain. The Oli-neu secretome regulates astrocyte genes known to modulate neuronal synaptic transmission and remodels calcium, chemokine, NOD-like receptor, PI3K-Akt, and thyroid hormone signaling, as well as actin-cytoskeleton, autophagy, cell cycle, and circadian rhythm pathways. Moreover, the co-culture significantly changes the gene hierarchy in the astrocytes.
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Affiliation(s)
- Dumitru A Iacobas
- Personalized Genomics Laboratory, Center for Computational Systems Biology, RG Perry College of Engineering, Prairie View A&M University, Prairie View, TX 77446, USA
- DP Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
- Correspondence: ; Tel.: +1-936-261-9926
| | - Sanda Iacobas
- Department of Pathology, New York Medical College, Valhalla, NY 10595, USA;
| | - Randy F Stout
- Department of Biomedical Sciences, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568, USA;
| | - David C Spray
- DP Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, New York, NY 10461, USA;
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7
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Filatov MA, Nikishin DA, Khramova YV, Semenova ML. The in vitro Analysis of Quality of Ovarian Follicle Culture Systems Using Time-Lapse Microscopy and Quantitative Real-Time PCR. J Reprod Infertil 2020; 21:94-106. [PMID: 32500012 PMCID: PMC7253941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The aim of ovarian follicle in vitro culture is to obtain mature oocytes. To evaluate the efficiency of in vitro culture system, the status of the cultured oocyte can be analyzed. METHODS The preantral ovarian follicles retrieved from 14-day-old C57Bl/6J mice were cultured in 3D alginate hydrogel. The status of oocytes obtained from mature (3 months old, group A) and immature (3 weeks old, group B) mice was compared to the status of oocytes retrieved from ovarian follicles cultured in vitro (Group C) using qRT-PCR analysis and time-lapse microscopy. In the qRT-PCR analysis, 8 samples for group A (80 oocytes), 8 samples for group B (80 oocytes), and 6 samples for group C (60 oocytes) were included. Time-lapse analysis was performed in group A (oocytes n=31), group B (n=45), and group C (n=21). Statistical analysis was done by Kruskal-Wallis and chi-square tests and differences were considered statistically significant if p<0,05. RESULTS The diameter of group C oocytes is lower in comparison to group A oocytes (67 μm vs. 75 μm, correspondingly). Groups B and C oocytes exhibited delayed meiosis in comparison to group A oocytes. Expression levels of six oocyte maturation genes (Ccnb, CDK1, Ccnh, Wee2, Mos and Epab) were evaluated using qRT-PCR analysis. Expression levels of Ccnh and Epab are lowered in group C oocytes compared to the expression levels of these genes in groups A and B oocytes (p< 0.05). CONCLUSION Oocytes obtained after ovarian follicles in vitro culture have reduced development competence, future fundamental changes of in vitro culture systems can be expected.
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Affiliation(s)
- Maxim Alexeevich Filatov
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia,Corresponding Author: Maxim Alexeevich Filatov, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia E-mail:
| | - Denis Alexandrovich Nikishin
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia, N.K. Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
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Identification of a 3,3-difluorinated tetrahydropyridinol compound as a novel antitumor agent for hepatocellular carcinoma acting via cell cycle arrest through disturbing CDK7-mediated phosphorylation of Cdc2. Invest New Drugs 2019; 38:287-298. [PMID: 31076964 DOI: 10.1007/s10637-019-00792-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 05/06/2019] [Indexed: 01/28/2023]
Abstract
Tetrahydropyridinol derivatives were recently reported to exhibit good biological activities, and the incorporation of fluorine into organic molecules may have profound effects on their physical and biological properties. Therefore, we investigated the anticancer activities of six fluorinated tetrahydropyridinol derivatives that we synthesized previously. We found that only one compound, 3,3-difluoro-2,2-dimethyl-1,6-diphenyl-5-tosyl-1,2,3,6-tetrahydropyridin-4-ol, showed significant antiproliferative activity on human hepatocellular carcinoma HepG2 and HMCCLM3 cells (the IC50 values were 21.25 and 29.07 μM, respectively). We also found that this compound mediated cell cycle arrest in the G0/G1 phase at 30-40 μM. Western blot analysis demonstrated that the cell cycle arrest induced by this compound in HepG2 and HMCCLM3 cells was associated with a significant decrease in Cdc2 and cyclin B1, which led to the accumulation of the phosphorylated-Tyr15 (inactive) form of Cdc2 and low expression of M phase-promoting factor (cyclin B1/Cdc2). Moreover, cells treated with this compound exhibited decreased expression of cyclin-dependent kinase (CDK)-activating kinase (CDK7/cyclin H). This compound also induced cell apoptosis via activation of caspase-3. A xenograft model in nude mice demonstrated anti-liver cancer activity and the mechanism of action of this compound. These findings indicated that the anticancer effect of this compound was partially due to G0/G1 cell cycle arrest via inhibition of CDK7-mediated expression of Cdc2, and this compound may be a promising anticancer candidate for further investigation.
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Rimel JK, Taatjes DJ. The essential and multifunctional TFIIH complex. Protein Sci 2018; 27:1018-1037. [PMID: 29664212 PMCID: PMC5980561 DOI: 10.1002/pro.3424] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/19/2022]
Abstract
TFIIH is a 10‐subunit complex that regulates RNA polymerase II (pol II) transcription but also serves other important biological roles. Although much remains unknown about TFIIH function in eukaryotic cells, much progress has been made even in just the past few years, due in part to technological advances (e.g. cryoEM and single molecule methods) and the development of chemical inhibitors of TFIIH enzymes. This review focuses on the major cellular roles for TFIIH, with an emphasis on TFIIH function as a regulator of pol II transcription. We describe the structure of TFIIH and its roles in pol II initiation, promoter‐proximal pausing, elongation, and termination. We also discuss cellular roles for TFIIH beyond transcription (e.g. DNA repair, cell cycle regulation) and summarize small molecule inhibitors of TFIIH and diseases associated with defects in TFIIH structure and function.
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Affiliation(s)
- Jenna K Rimel
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado, 80303
| | - Dylan J Taatjes
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado, 80303
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10
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Chen D, Zhou L, Sun F, Sun M, Tao X. Cyclin B3 Deficiency Impairs Germline Stem Cell Maintenance and Its Overexpression Delays Cystoblast Differentiation in Drosophila Ovary. Int J Mol Sci 2018; 19:ijms19010298. [PMID: 29351213 PMCID: PMC5796243 DOI: 10.3390/ijms19010298] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 01/14/2018] [Accepted: 01/16/2018] [Indexed: 11/16/2022] Open
Abstract
It is well known that cyclinB3 (cycB3) plays a key role in the control of cell cycle progression. However, whether cycB3 is involved in stem cell fate determination remains unknown. The Drosophila ovary provides an exclusive model for studying the intrinsic and extrinsic factors that modulate the fate of germline stem cells (GSCs). Here, using this model, we show that DrosophilacycB3 plays a new role in controlling the fate of germline stem cells (GSC). Results from cycB3 genetic analyses demonstrate that cycB3 is intrinsically required for GSC maintenance. Results from green fluorescent protein (GFP)-transgene reporter assays show that cycB3 is not involved in Dad-mediated regulation of Bmp signaling, or required for dpp-induced bam transcriptional silencing. Double mutants of bam and cycB3 phenocopied bam single mutants, suggesting that cycB3 functions in a bam-dependent manner in GSCs. Deficiency of cycB3 fails to cause apoptosis in GSCs or influence cystoblast (CB) differentiation into oocytes. Furthermore, overexpression of cycB3 dramatically increases the CB number in Drosophila ovaries, suggesting that an excess of cycB3 function delays CB differentiation. Given that the cycB3 gene is evolutionarily conserved, from insects to humans, cycB3 may also be involved in controlling the fate of GSCs in humans.
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Affiliation(s)
- Dongsheng Chen
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
- The Institute of Bioinformatics, College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
| | - Lijuan Zhou
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
| | - Fuling Sun
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
| | - Mingzhong Sun
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
| | - Xiaoqian Tao
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
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Hung JH, Chen CY, Omar HA, Huang KY, Tsao CC, Chiu CC, Chen YL, Chen PH, Teng YN. Reactive oxygen species mediate Terbufos-induced apoptosis in mouse testicular cell lines via the modulation of cell cycle and pro-apoptotic proteins. ENVIRONMENTAL TOXICOLOGY 2016; 31:1888-1898. [PMID: 26370073 DOI: 10.1002/tox.22190] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/20/2015] [Accepted: 07/26/2015] [Indexed: 05/04/2023]
Abstract
Terbufos (S-t-butylthiomethyl-O,O-diethyl phosphorodithioate) is a highly toxic organophosphate which is extensively used as an insecticide and nematicide. Chronic exposure to terbufos causes neuronal injury and predisposes to neurodegenerative diseases. Accumulating evidence has shown that the exposure to terbufos, as an occupational risk factor, may also cause reproductive disorders. However, the exact mechanisms of reproductive toxicity remain unclear. The present study aimed to investigate the toxic effect of terbufos on testicular cells and to explore the mechanism of toxicity on a cellular level. The cytotoxic effects of terbufos on mouse immortalized spermatogonia (GC-1), spermatocytes (GC-2), Leydig (TM3), and Sertoli (TM4) cell lines were assessed by MTT assays, caspase activation, flow cytometry, TUNEL assay, Western blot, and cell cycle analysis. The exposure to different concentrations of terbufos ranging from 50 to 800 μM for 6 h caused significant death in all the used testicular cell lines. Terbufos increased reactive oxygen species (ROS) production, reduced mitochondrial membrane potential, and initiated apoptosis, which was confirmed by a dose-dependent increase in the number of TUNEL-positive apoptotic cells. Blocking ROS production by N-acetyl cysteine (NAC) protected GC-1 cells from terbufos-induced cell death. The results demonstrated that terbufos induces ROS, apoptosis, and DNA damage in testicular cell lines and it should be considered potentially hazardous to testis. Together, this study provided potential molecular mechanisms of terbufos-induced toxicity in testicular cells and suggests a possible protective measure. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1888-1898, 2016.
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Affiliation(s)
- Jui-Hsiang Hung
- Department of Biotechnology, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
- Drug Discovery and Development Center, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Chia-Yun Chen
- Department of Biotechnology, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Hany A Omar
- Department of Pharmacology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef, 62514, Egypt
- Department of Pharmacology, College of Pharmacy, Sharjah Institute for Medical Research, University of Sharjah, Sharjah, 27272, UAE
| | - Kuo-Yuan Huang
- Department of Orthopedics, National Cheng Kung University, College of Medicine, Tainan, Taiwan
| | - Che-Chia Tsao
- Department of Biological Sciences and Technology, National University of Tainan, Tainan, Taiwan
| | - Chien-Chih Chiu
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Ling Chen
- Department of Senior Citizen Service Management, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Po-Han Chen
- Department of Cosmetic Application & Management, Far East University, Tainan, Taiwan
| | - Yen-Ni Teng
- Department of Biological Sciences and Technology, National University of Tainan, Tainan, Taiwan
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12
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Naseh G, Mohammadifard M, Mohammadifard M. Upregulation of cyclin-dependent kinase 7 and matrix metalloproteinase-14 expression contribute to metastatic properties of gastric cancer. IUBMB Life 2016; 68:799-805. [PMID: 27562173 DOI: 10.1002/iub.1543] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 08/10/2016] [Indexed: 01/01/2023]
Abstract
The aim of this study was to evaluate the protein and mRNA expressions of matrix metalloproteinase-14 (MMP14) and CDK7 in gastric cancer (GC) tissues. Upregulation of MMP14 mRNA level was observed in GC tissues when compared with the matched normal tissues (mean ± SD: 3.92 ± 1.15 vs. 1.35 ± 0.81, P < 0.001). This study indicated that mRNA levels of CDK7 were statistically overexpressed in GC when compared with matched normal tissues (4.12 ± 0.84 vs. 1.43 ± 0.71, P < 0.001). The protein levels of MMP14 were found to be increased in GC (60.41%; P < 0.001). The expression of CDK7 was higher in GC tissues than matched normal tissues (70.83; P < 0.001). We found that high MMP14 expression was related to advanced TNM stage (P = 0.004), tumor grade (P = 0.002), and lymph node metastasis (P = 0.015), but no association with other clinical variables (P > 0.05). In addition, high expression of CDK7 was significantly linked to advanced TNM stage (P = 0.001), pathological grade (P = 0.012), and presence of lymph node metastasis (P = 0.009), while no correlation between CDK7 expression and other clinical variables, such as age and gender, distance metastasis. The patients with high expression of MMP14 and CDK7 exhibited worse survival time than those with higher levels. Cox multivariate regression analysis clearly showed that high expression of MMP14 and CDK7 was independent prognostic factors for overall survival in patients with GC. Taken together, these results indicated the overexpression of above markers in the progression and the tumorigenesis of GC and overall patient survival. © 2016 IUBMB Life, 68(10):799-805, 2016.
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Affiliation(s)
- Ghodratolah Naseh
- Department of Surgery, Imam Reza Hospital, Birjand University of Medical Sciences, Birjand, Iran
| | - Mahyar Mohammadifard
- Department of Radiology, Imam Reza Hospital, Birjand University of Medical Sciences, Birjand, Iran.
| | - Mahtab Mohammadifard
- Department of Pathology, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran
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13
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Abstract
The preimplantation development stage of mammalian embryogenesis consists of a series of highly conserved, regulated, and predictable cell divisions. This process is essential to allow the rapid expansion and differentiation of a single-cell zygote into a multicellular blastocyst containing cells of multiple developmental lineages. This period of development, also known as the germinal stage, encompasses several important developmental transitions, which are accompanied by dramatic changes in cell cycle profiles and dynamics. These changes are driven primarily by differences in the establishment and enforcement of cell cycle checkpoints, which must be bypassed to facilitate the completion of essential cell cycle events. Much of the current knowledge in this area has been amassed through the study of knockout models in mice. These mouse models are powerful experimental tools, which have allowed us to dissect the relative dependence of the early embryonic cell cycles on various aspects of the cell cycle machinery and highlight the extent of functional redundancy between members of the same gene family. This chapter will explore the ways in which the cell cycle machinery, their accessory proteins, and their stimuli operate during mammalian preimplantation using mouse models as a reference and how this allows for the usually well-defined stages of the cell cycle to be shaped and transformed during this unique and critical stage of development.
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14
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Upregulation of CDK7 in gastric cancer cell promotes tumor cell proliferation and predicts poor prognosis. Exp Mol Pathol 2016; 100:514-21. [PMID: 27155449 DOI: 10.1016/j.yexmp.2016.05.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 04/13/2016] [Accepted: 05/02/2016] [Indexed: 12/19/2022]
Abstract
CDK7 has been known as a component of CDK activating kinase (CAK) complex, the complex was composed of CDK7, Cyclin H and RING finger protein Mat1 that contribute to cell cycle progression by phosphorylating other CDKs. In addition, the complex is also an essential component of general transcription factor TFIIH which controls transcription via activating RNA polymerase II by serines 5 and 7 phosphorylation of the carboxyl-terminal domain (CTD) of its largest subunit. However, the role of CDK7 in the pathogenesis of gastric cancer has not been identified. Our study showed that CDK7 was significantly upregulated and positively correlated with tumor grade, infiltration depth, lymph node, Ki-67, and predicted poor prognosis in 173 gastric cancer specimens by immunohistochemistrical analyses. Furthermore, in vitro results indicated that CDK7 promoted proliferation of gastric cancer cells by CCK8, clone formation analyses and flow cytometric analyses, while CDK7 knockdown led to decreased cell proliferation. Our study will provide a theoretical basis for the study of CDK7 in gastric cancer.
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15
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Mason EA, Mar JC, Laslett AL, Pera MF, Quackenbush J, Wolvetang E, Wells CA. Gene expression variability as a unifying element of the pluripotency network. Stem Cell Reports 2014; 3:365-77. [PMID: 25254348 PMCID: PMC4175554 DOI: 10.1016/j.stemcr.2014.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 06/18/2014] [Accepted: 06/20/2014] [Indexed: 12/16/2022] Open
Abstract
Heterogeneity is a hallmark of stem cell populations, in part due to the molecular differences between cells undergoing self-renewal and those poised to differentiate. We examined phenotypic and molecular heterogeneity in pluripotent stem cell populations, using public gene expression data sets. A high degree of concordance was observed between global gene expression variability and the reported heterogeneity of different human pluripotent lines. Network analysis demonstrated that low-variability genes were the most highly connected, suggesting that these are the most stable elements of the gene regulatory network and are under the highest regulatory constraints. Known drivers of pluripotency were among these, with lowest expression variability of POU5F1 in cells with the highest capacity for self-renewal. Variability of gene expression provides a reliable measure of phenotypic and molecular heterogeneity and predicts those genes with the highest degree of regulatory constraint within the pluripotency network. Gene expression variability is highly concordant with population heterogeneity Genes within the pluripotency network have distinct variability profiles Expression variability is a network property important for pluripotency
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Affiliation(s)
- Elizabeth A Mason
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, Brisbane QSLD 4072, Australia
| | - Jessica C Mar
- The Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Andrew L Laslett
- Materials Science and Engineering, CSIRO, Clayton VIC 3168, Australia
| | - Martin F Pera
- The University of Melbourne, Florey Neuroscience and Mental Health Institute, and Walter and Eliza Hall Institute of Medical Research, Parkville VIC 3010, Australia
| | - John Quackenbush
- Dana-Farber Cancer Institute, Harvard University, Boston, MA 02215 USA
| | - Ernst Wolvetang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, Brisbane QSLD 4072, Australia
| | - Christine A Wells
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, Brisbane QSLD 4072, Australia; Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK.
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16
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Papadodima O, Chatziioannou A, Patrinou-Georgoula M, Kolisis FN, Pletsa V, Guialis A. HuR-regulated mRNAs associated with nuclear hnRNP A1-RNP complexes. Int J Mol Sci 2013; 14:20256-81. [PMID: 24152440 PMCID: PMC3821614 DOI: 10.3390/ijms141020256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/06/2013] [Accepted: 09/16/2013] [Indexed: 12/13/2022] Open
Abstract
Post-transcriptional regulatory networks are dependent on the interplay of many RNA-binding proteins having a major role in mRNA processing events in mammals. We have been interested in the concerted action of the two RNA-binding proteins hnRNP A1 and HuR, both stable components of immunoselected hnRNP complexes and having a major nuclear localization. Specifically, we present here the application of the RNA-immunoprecipitation (RIP)-Chip technology to identify a population of nuclear transcripts associated with hnRNP A1-RNPs as isolated from the nuclear extract of either HuR WT or HuR-depleted (KO) mouse embryonic fibroblast (MEF) cells. The outcome of this analysis was a list of target genes regulated via HuR for their association (either increased or reduced) with the nuclear hnRNP A1-RNP complexes. Real time PCR analysis was applied to validate a selected number of nuclear mRNA transcripts, as well as to identify pre-spliced transcripts (in addition to their mature mRNA counterpart) within the isolated nuclear hnRNP A1-RNPs. The differentially enriched mRNAs were found to belong to GO categories relevant to biological processes anticipated for hnRNP A1 and HuR (such as transport, transcription, translation, apoptosis and cell cycle) indicating their concerted function in mRNA metabolism.
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Affiliation(s)
- Olga Papadodima
- Division of Biological Research and Biotechnology, Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, Athens 11635, Greece; E-Mails: (O.P.); (A.C.); (M.P.-G.)
| | - Aristotelis Chatziioannou
- Division of Biological Research and Biotechnology, Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, Athens 11635, Greece; E-Mails: (O.P.); (A.C.); (M.P.-G.)
| | - Meropi Patrinou-Georgoula
- Division of Biological Research and Biotechnology, Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, Athens 11635, Greece; E-Mails: (O.P.); (A.C.); (M.P.-G.)
| | - Fragiskos N. Kolisis
- Laboratory of Biotechnology, School of Chemical Engineering, National Technical University of Athens, Athens 15780, Greece; E-Mail:
| | - Vasiliki Pletsa
- Division of Biological Research and Biotechnology, Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, Athens 11635, Greece; E-Mails: (O.P.); (A.C.); (M.P.-G.)
- Authors to whom correspondence should be addressed; E-Mails: (V.P.); (A.G.); Tel.: +30-210-7273-754 (V.P. & A.G.); Fax: +30-210-7273-677 (V.P. & A.G.)
| | - Apostolia Guialis
- Division of Biological Research and Biotechnology, Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, Athens 11635, Greece; E-Mails: (O.P.); (A.C.); (M.P.-G.)
- Authors to whom correspondence should be addressed; E-Mails: (V.P.); (A.G.); Tel.: +30-210-7273-754 (V.P. & A.G.); Fax: +30-210-7273-677 (V.P. & A.G.)
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Abstract
Cyclin-dependent kinases (Cdks) are serine/threonine kinases and their catalytic activities are modulated by interactions with cyclins and Cdk inhibitors (CKIs). Close cooperation between this trio is necessary for ensuring orderly progression through the cell cycle. In addition to their well-established function in cell cycle control, it is becoming increasingly apparent that mammalian Cdks, cyclins and CKIs play indispensable roles in processes such as transcription, epigenetic regulation, metabolism, stem cell self-renewal, neuronal functions and spermatogenesis. Even more remarkably, they can accomplish some of these tasks individually, without the need for Cdk/cyclin complex formation or kinase activity. In this Review, we discuss the latest revelations about Cdks, cyclins and CKIs with the goal of showcasing their functional diversity beyond cell cycle regulation and their impact on development and disease in mammals.
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Affiliation(s)
- Shuhui Lim
- Institute of Molecular and Cell Biology IMCB, A*STAR Agency for Science, Technology and Research, Singapore 138673, Republic of Singapore
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18
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Low expression of cyclinH and cyclin-dependent kinase 7 can decrease the proliferation of human esophageal squamous cell carcinoma. Dig Dis Sci 2013; 58:2028-37. [PMID: 23456497 DOI: 10.1007/s10620-013-2597-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 02/06/2013] [Indexed: 01/09/2023]
Abstract
BACKGROUND Increased expression of cyclinH (CCNH) and cyclin-dependent kinase 7 (CDK7) has a relationship with poor prognosis in most human cancers. AIM Investigate the expression of CCNH and CDK7 in human esophageal squamous cell carcinoma (ESCC) and the effect of chemotherapy on their expression. METHODS Western blotting and immunohistochemistry were used to measure the expression of CCNH and CDK7 proteins in ESCC and adjacent normal tissue in 98 patients. We use Cell Counting Kit-8 and cell flow to analyze the effects of cisplatin and interference of CCNH and CDK7 in cell cycle process. RESULTS Immunohistochemical analysis showed that CCNH and CDK7 expression were significantly associated with unfavorable clinicopathologic variables. CCNH and CDK7 protein levels were elevated in ESCC tissues in comparison with adjacent normal tissues. Survival analysis revealed that CCNH and CDK7 overexpression were significantly associated with overall survival (P < 0.001). Cisplatin or interference of CCNH or CDK7 led cells to grow slowly. Overexpression of CCNH and CDK7 in TE1 cells can lead to resistance to cisplatin. CONCLUSIONS We can conclude that CCNH and CDK7 may play an important role in the tumorigenesis and development of ESCC. CCNH and CDK7 expression affected the chemotherapy of tumor.
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Casimiro MC, Crosariol M, Loro E, Li Z, Pestell RG. Cyclins and cell cycle control in cancer and disease. Genes Cancer 2013; 3:649-57. [PMID: 23634253 DOI: 10.1177/1947601913479022] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cyclin D1 overexpression is found in more than 50% of human breast cancers and causes mammary cancer in transgenic mice. Dysregulation of cyclin D1 gene expression or function contributes to the loss of normal cell cycle control during tumorigenesis. Recent studies have demonstrated that cyclin D1 conducts additional specific functions to regulate gene expression in the context of local chromatin, promote cellular migration, and promote chromosomal instability. It is anticipated that these additional functions contribute to the pathology associated with dysregulated cyclin D1 abundance. This article discusses evidence that examines the functional roles that cyclin D1 may play in cancer with an emphasis on other cyclin family members that also may contribute to cancer and disease in a similar fashion.
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20
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TIAN YE, WAN HAN, TAN GUANG. Cell cycle-related kinase in carcinogenesis. Oncol Lett 2012; 4:601-606. [PMID: 23205069 PMCID: PMC3506610 DOI: 10.3892/ol.2012.828] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 07/24/2012] [Indexed: 12/16/2022] Open
Abstract
Cell cycle-related kinase (CCRK) is a novel protein kinase homologous to both cyclin-dependent kinase 7 (Cdk7) and Cak1p groups of CDK-activating kinase (CAK). CCRK activates Cdk2, which controls the cell-cycle progression by phosphorylating a threonine residue conserved in Cdk2. Previous studies have indicated that the CCRK protein levels were elevated by more than 1.5-fold in tumor tissue, and that the overexpression of CCRK is associated with poor prognosis of the patients. Moreover, recent studies have shown that CCRK is involved in the Wnt signaling pathway associated with the genesis and evolution of cancer. This review aims to systematically present the information currently available on CCRK obtained from in vitro and in vivo studies and highlight its significance to tumorigenesis.
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Affiliation(s)
- YE TIAN
- Department of General Surgery, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning 116011,
P.R. China
| | - HAN WAN
- Department of General Surgery, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning 116011,
P.R. China
| | - GUANG TAN
- Department of General Surgery, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning 116011,
P.R. China
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21
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Depamphilis ML, de Renty CM, Ullah Z, Lee CY. "The Octet": Eight Protein Kinases that Control Mammalian DNA Replication. Front Physiol 2012; 3:368. [PMID: 23055977 PMCID: PMC3458233 DOI: 10.3389/fphys.2012.00368] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Accepted: 08/27/2012] [Indexed: 01/12/2023] Open
Abstract
Development of a fertilized human egg into an average sized adult requires about 29 trillion cell divisions, thereby producing enough DNA to stretch to the Sun and back 200 times (DePamphilis and Bell, 2011)! Even more amazing is the fact that throughout these mitotic cell cycles, the human genome is duplicated once and only once each time a cell divides. If a cell accidentally begins to re-replicate its nuclear DNA prior to cell division, checkpoint pathways trigger apoptosis. And yet, some cells are developmentally programmed to respond to environmental cues by switching from mitotic cell cycles to endocycles, a process in which multiple S phases occur in the absence of either mitosis or cytokinesis. Endocycles allow production of viable, differentiated, polyploid cells that no longer proliferate. What is surprising is that among the 516 (Manning et al., 2002) to 557 (BioMart web site) protein kinases encoded by the human genome, only eight regulate nuclear DNA replication directly. These are Cdk1, Cdk2, Cdk4, Cdk6, Cdk7, Cdc7, Checkpoint kinase-1 (Chk1), and Checkpoint kinase-2. Even more remarkable is the fact that only four of these enzymes (Cdk1, Cdk7, Cdc7, and Chk1) are essential for mammalian development. Here we describe how these protein kinases determine when DNA replication occurs during mitotic cell cycles, how mammalian cells switch from mitotic cell cycles to endocycles, and how cancer cells can be selectively targeted for destruction by inducing them to begin a second S phase before mitosis is complete.
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Affiliation(s)
- Melvin L Depamphilis
- Program in Genomics of Differentiation, National Institute of Child Health and Human Development, National Institutes of Health Bethesda, MD, USA
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22
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Ganuza M, Sáiz-Ladera C, Cañamero M, Gómez G, Schneider R, Blasco MA, Pisano D, Paramio JM, Santamaría D, Barbacid M. Genetic inactivation of Cdk7 leads to cell cycle arrest and induces premature aging due to adult stem cell exhaustion. EMBO J 2012; 31:2498-510. [PMID: 22505032 DOI: 10.1038/emboj.2012.94] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 03/20/2012] [Indexed: 01/09/2023] Open
Abstract
Cyclin-dependent kinase (Cdk)7, the catalytic subunit of the Cdk-activating kinase (CAK) complex has been implicated in the control of cell cycle progression and of RNA polymerase II (RNA pol II)-mediated transcription. Genetic inactivation of the Cdk7 locus revealed that whereas Cdk7 is completely dispensable for global transcription, is essential for the cell cycle via phosphorylation of Cdk1 and Cdk2. In vivo, Cdk7 is also indispensable for cell proliferation except during the initial stages of embryonic development. Interestingly, widespread elimination of Cdk7 in adult tissues with low proliferative indexes had no phenotypic consequences. However, ablation of conditional Cdk7 alleles in tissues with elevated cellular turnover led to the efficient repopulation of these tissues with Cdk7-expressing cells most likely derived from adult stem cells that may have escaped the inactivation of their targeted Cdk7 alleles. This process, a physiological attempt to maintain tissue homeostasis, led to the attrition of adult stem cell pools and to the appearance of age-related phenotypes, including telomere shortening and early death.
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Affiliation(s)
- Miguel Ganuza
- Experimental Oncology, Molecular Oncology Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid, Spain
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