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Deregulated E2F Activity as a Cancer-Cell Specific Therapeutic Tool. Genes (Basel) 2023; 14:genes14020393. [PMID: 36833320 PMCID: PMC9956157 DOI: 10.3390/genes14020393] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/24/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
The transcription factor E2F, the principal target of the tumor suppressor pRB, plays crucial roles in cell proliferation and tumor suppression. In almost all cancers, pRB function is disabled, and E2F activity is enhanced. To specifically target cancer cells, trials have been undertaken to suppress enhanced E2F activity to restrain cell proliferation or selectively kill cancer cells, utilizing enhanced E2F activity. However, these approaches may also impact normal growing cells, since growth stimulation also inactivates pRB and enhances E2F activity. E2F activated upon the loss of pRB control (deregulated E2F) activates tumor suppressor genes, which are not activated by E2F induced by growth stimulation, inducing cellular senescence or apoptosis to protect cells from tumorigenesis. Deregulated E2F activity is tolerated in cancer cells due to inactivation of the ARF-p53 pathway, thus representing a feature unique to cancer cells. Deregulated E2F activity, which activates tumor suppressor genes, is distinct from enhanced E2F activity, which activates growth-related genes, in that deregulated E2F activity does not depend on the heterodimeric partner DP. Indeed, the ARF promoter, which is specifically activated by deregulated E2F, showed higher cancer-cell specific activity, compared to the E2F1 promoter, which is also activated by E2F induced by growth stimulation. Thus, deregulated E2F activity is an attractive potential therapeutic tool to specifically target cancer cells.
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2
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Jaiswal N, Nandi D, Cheema PS, Nag A. The anaphase-promoting complex/cyclosome co-activator, Cdh1, is a novel target of human papillomavirus 16 E7 oncoprotein in cervical oncogenesis. Carcinogenesis 2022; 43:988-1001. [PMID: 35738876 DOI: 10.1093/carcin/bgac057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 06/01/2022] [Accepted: 06/23/2022] [Indexed: 01/13/2023] Open
Abstract
The transforming properties of the high-risk human papillomavirus (HPV) E7 oncoprotein are indispensable for driving the virus life cycle and pathogenesis. Besides inactivation of the retinoblastoma family of tumor suppressors as part of its oncogenic endeavors, E7-mediated perturbations of eminent cell cycle regulators, checkpoint proteins and proto-oncogenes are considered to be the tricks of its transformative traits. However, many such critical interactions are still unknown. In the present study, we have identified the anaphase-promoting complex/cyclosome (APC) co-activator, Cdh1, as a novel interacting partner and a degradation target of E7. We found that HPV16 E7-induced inactivation of Cdh1 promoted abnormal accumulation of multiple Cdh1 substrates. Such a mode of deregulation possibly contributes to HPV-mediated cervical oncogenesis. Our mapping studies recognized the C-terminal zinc-finger motif of E7 to associate with Cdh1 and interfere with the timely degradation of FoxM1, a bona fide Cdh1 substrate and a potent oncogene. Importantly, the E7 mutant with impaired interaction with Cdh1 exhibited defects in its ability for overriding typical cell cycle transition and oncogenic transformation, thereby validating the functional and pathological significance of the E7-Cdh1 axis during cervical carcinoma progression. Altogether, the findings from our study discover a unique nexus between E7 and APC/C-Cdh1, thereby adding to our understanding of the mechanism of E7-induced carcinogenesis and provide a promising target for the management of cervical carcinoma.
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Affiliation(s)
- Neha Jaiswal
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Marg, New Delhi, India
| | - Deeptashree Nandi
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Marg, New Delhi, India
| | - Pradeep Singh Cheema
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Marg, New Delhi, India
| | - Alo Nag
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Marg, New Delhi, India
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3
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Han W, Liu M, Han D, Toure AA, Li M, Besschetnova A, Wang Z, Patalano S, Macoska JA, Lam HM, Corey E, He HH, Gao S, Balk SP, Cai C. Exploiting the tumor-suppressive activity of the androgen receptor by CDK4/6 inhibition in castration-resistant prostate cancer. Mol Ther 2022; 30:1628-1644. [PMID: 35121110 PMCID: PMC9077383 DOI: 10.1016/j.ymthe.2022.01.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 12/15/2021] [Accepted: 01/28/2022] [Indexed: 10/19/2022] Open
Abstract
The androgen receptor (AR) plays a pivotal role in driving prostate cancer (PCa) development. However, when stimulated by high levels of androgens, AR can also function as a tumor suppressor in PCa cells. While the high-dose testosterone (high-T) treatment is currently being tested in clinical trials of castration-resistant prostate cancer (CRPC), there is still a pressing need to fully understand the underlying mechanism and thus develop treatment strategies to exploit this tumor-suppressive activity of AR. In this study, we demonstrate that retinoblastoma (Rb) family proteins play a central role in maintaining the global chromatin binding and transcriptional repression program of AR and that Rb inactivation desensitizes CRPC to the high-dose testosterone treatment in vitro and in vivo. Using a series of patient-derived xenograft (PDX) CRPC models, we further show that the efficacy of high-T treatment can be fully exploited by a CDK4/6 inhibitor, which strengthens the chromatin binding of the Rb-E2F repressor complex by blocking the hyperphosphorylation of Rb proteins. Overall, our study provides strong mechanistic and preclinical evidence on further developing clinical trials to combine high-T with CDK4/6 inhibitors in treating CRPC.
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4
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Weiner F, Schille JT, Koczan D, Wu XF, Beller M, Junghanss C, Hewicker-Trautwein M, Murua Escobar H, Nolte I. Novel chemotherapeutic agent FX-9 activates NF-κB signaling and induces G1 phase arrest by activating CDKN1A in a human prostate cancer cell line. BMC Cancer 2021; 21:1088. [PMID: 34625047 PMCID: PMC8501574 DOI: 10.1186/s12885-021-08836-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/24/2021] [Indexed: 11/23/2022] Open
Abstract
Background The aminoisoquinoline FX-9 shows pro-apoptotic and antimitotic effects against lymphoblastic leukemia cells and prostate adenocarcinoma cells. In contrast, decreased cytotoxic effects against non-neoplastic blood cells, chondrocytes, and fibroblasts were observed. However, the actual FX-9 molecular mode of action is currently not fully understood. Methods In this study, microarray gene expression analysis comparing FX-9 exposed and unexposed prostate cancer cells (PC-3 representing castration-resistant prostate cancer), followed by pathway analysis and gene annotation to functional processes were performed. Immunocytochemistry staining was performed with selected targets. Results Expression analysis revealed 0.83% of 21,448 differential expressed genes (DEGs) after 6-h exposure of FX-9 and 0.68% DEGs after 12-h exposure thereof. Functional annotation showed that FX-9 primarily caused an activation of inflammatory response by non-canonical nuclear factor-kappa B (NF-κB) signaling. The 6-h samples showed activation of the cell cycle inhibitor CDKN1A which might be involved in the secondary response in 12-h samples. This secondary response predominantly consisted of cell cycle-related changes, with further activation of CDKN1A and inhibition of the transcription factor E2F1, including downstream target genes, resulting in G1-phase arrest. Matching our previous observations on cellular level senescence signaling pathways were also found enriched. To verify these results immunocytochemical staining of p21 Waf1/Cip1 (CDKN1A), E2F1 (E2F1), PAI-1 (SERPNE1), and NFkB2/NFkB p 100 (NFKB2) was performed. Increased expression of p21 Waf1/Cip1 and NFkB2/NFkB p 100 after 24-h exposure to FX-9 was shown. E2F1 and PAI-1 showed no increased expression. Conclusions FX-9 induced G1-phase arrest of PC-3 cells through activation of the cell cycle inhibitor CDKN1A, which was initiated by an inflammatory response of noncanonical NF-κB signaling. Supplementary Information The online version contains supplementary material available at 10.1186/s12885-021-08836-y.
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Affiliation(s)
- F Weiner
- Small Animal Clinic, University of Veterinary Medicine Hannover, 30559, Hannover, Germany.,Department of Medicine, Clinic III, Hematology, Oncology, Palliative Medicine, University of Rostock, 18057, Rostock, Germany
| | - J T Schille
- Small Animal Clinic, University of Veterinary Medicine Hannover, 30559, Hannover, Germany.,Department of Medicine, Clinic III, Hematology, Oncology, Palliative Medicine, University of Rostock, 18057, Rostock, Germany
| | - D Koczan
- Core Facility for Microarray Analysis, Institute for Immunology, University of Rostock, 18057, Rostock, Germany
| | - X-F Wu
- Leibniz Institute for Catalysis, 18059, Rostock, Germany
| | - M Beller
- Leibniz Institute for Catalysis, 18059, Rostock, Germany
| | - C Junghanss
- Department of Medicine, Clinic III, Hematology, Oncology, Palliative Medicine, University of Rostock, 18057, Rostock, Germany
| | - M Hewicker-Trautwein
- Department of Pathology, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - H Murua Escobar
- Department of Medicine, Clinic III, Hematology, Oncology, Palliative Medicine, University of Rostock, 18057, Rostock, Germany.,Comprehensive Cancer Center - Mecklenburg Vorpommern (CCC-MV), Campus Rostock, University of Rostock, 18057, Rostock, Germany
| | - I Nolte
- Small Animal Clinic, University of Veterinary Medicine Hannover, 30559, Hannover, Germany.
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5
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Liu H, Lu Z, Shi X, Liu L, Zhang P, Golemis EA, Tu Z. HSP90 inhibition downregulates DNA replication and repair genes via E2F1 repression. J Biol Chem 2021; 297:100996. [PMID: 34302809 PMCID: PMC8363837 DOI: 10.1016/j.jbc.2021.100996] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 07/09/2021] [Accepted: 07/19/2021] [Indexed: 12/15/2022] Open
Abstract
Mantle cell lymphoma (MCL) is an especially aggressive and highly heterogeneous mature B-cell lymphoma. Heat shock protein 90 (HSP90) is considered an attractive therapeutic target in a variety of cancers, including MCL, but no HSP90 inhibitors have succeeded in the clinical trials to date. Exploring fine mechanisms of HSP90 inhibition in cancer cells may shed light on novel therapeutic strategies. Here, we found that HSP90 knockdown and continuous inhibition with ganetespib inhibited growth of MCL cells in vitro and in vivo. To our surprise, transient exposure over 12 h was almost as efficient as continuous exposure, and treatment with ganetespib for 12 h efficiently inhibited growth and induced G1 cell cycle arrest and apoptosis of MCL cells. Transcriptome analysis complemented by functional studies was performed to define critical MCL signaling pathways that are exceptionally sensitive to HSP90 inhibition and vital to cell fate. Six genes (cell division cycle 6, cell division cycle 45, minichromosome maintenance 4, minichromosome maintenance 7, RecQ-mediated genome instability 2, and DNA primase polypeptide 1) involved in DNA replication and repair were identified as consistently downregulated in three MCL cell lines after transient ganetespib treatment. E2F1, an important transcription factor essential for cell cycle progression, was identified as a ganetespib target mediating transcriptional downregulation of these six genes, and its stability was also demonstrated to be maintained by HSP90. This study identifies E2F1 as a novel client protein of HSP90 that is very sensitive and worthy of targeting and also finds that HSP90 inhibitors may be useful in combination therapies for MCL.
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Affiliation(s)
- Hanqing Liu
- School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Ziwen Lu
- School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Xiaofeng Shi
- Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Lanlan Liu
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Peishan Zhang
- School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu, China; Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
| | - Erica A Golemis
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
| | - Zhigang Tu
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, China.
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Transcriptome analysis of signaling pathways targeted by Ellagic acid in hepatocellular carcinoma cells. Biochim Biophys Acta Gen Subj 2021; 1865:129911. [PMID: 33862123 DOI: 10.1016/j.bbagen.2021.129911] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 04/06/2021] [Accepted: 04/08/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Ellagic acid (EA) possesses prominent inhibitory activities against various cancers, including hepatocellular carcinoma (HCC). Our recent study demonstrated EA's activities in reducing HCC cell proliferation and tumor formation. However, the mechanisms of EA to exert its anticancer activities and its primary targets in cancer cells have not been systematically explored. METHODS Cell proliferation assay and flow cytometric analysis were used to examine the effects of EA treatment on viability and apoptosis, respectively, of HepG2 cells. RNA-seq studies and associated pathway analyses by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were employed to determine EA's primary targets. Differentially expressed genes (DEG) in EA-treated HepG2 cells were verified by RT-qPCR and Western blot. Integrative analyses of the RNA-seq dataset with a TCGA dataset derived from HCC patients were conducted to verify EA-targeted genes and signaling pathways. Interaction network analysis of the DEGs, shRNA-mediated knockdown, cell viability assay, and colony formation assay were used to validate EA's primary targets. RESULTS EA reduced cell viability, caused DNA damage, and induced cell cycle arrest at G1 phase of HepG2 cells. We identified 5765 DEGs encoding proteins with over 2.0-fold changes in EA-treated HepG2 cells by DESeq2. These DEGs showed significant enrichment in the pathways regulating DNA replication and cell cycle progression. As primary targets, p21 was significantly upregulated, while MCM2-7 were uniformly downregulated in response to EA treatment. Consistently, p21 knockdown desensitized liver cells to EA in cell viability and colony formation assays. CONCLUSION EA induced G1 phase arrest and promoted apoptosis of HCC cells through activating the p21 gene and downregulating the MCM2-7 genes, respectively. GENERAL SIGNIFICANCE The discoveries in this study provide helpful insights into developing novel strategies in the therapeutic treatment of HCC patients.
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7
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Morimoto Y, Mizushima T, Wu X, Okuzaki D, Yokoyama Y, Inoue A, Hata T, Hirose H, Qian Y, Wang J, Miyoshi N, Takahashi H, Haraguchi N, Matsuda C, Doki Y, Mori M, Yamamoto H. miR-4711-5p regulates cancer stemness and cell cycle progression via KLF5, MDM2 and TFDP1 in colon cancer cells. Br J Cancer 2020; 122:1037-1049. [PMID: 32066912 PMCID: PMC7109136 DOI: 10.1038/s41416-020-0758-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 12/31/2019] [Accepted: 01/30/2020] [Indexed: 11/11/2022] Open
Abstract
Background It is important to establish cancer stem cell (CSC)-targeted therapies to eradicate cancer. As it is a CSC marker, we focused on Kruppel-like factor 5 (KLF5) in this study. Methods We searched for candidate microRNAs (miRNAs) that inhibited KLF5 expression by in silico analyses and screened them in colon cancer cell lines. Results We identified one promising miRNA, miR-4711-5p, that downregulated KLF5 expression by direct binding. This miRNA suppressed cell proliferation, migration and invasion ability, as well as stemness, including decreased stem cell marker expression, reactive oxygen species activity and sphere formation ability. MiR-4711-5p inhibited the growth of DLD-1 xenografts in nude mice with no adverse effects. We found that miR-4711-5p provoked G1 arrest, which could be attributed to direct binding of miR-4711-5p to TFDP1 (a heterodimeric partner of the E2F family). Our findings also suggested that direct binding of miR-4711-5p to MDM2 could upregulate wild-type p53, leading to strong induction of apoptosis. Finally, we found that miR-4711-5p had a potent tumour-suppressive effect compared with a putative anti-oncomiR, miR-34a, in tumour cell cultures derived from five patients with colorectal cancer. Conclusions Our data suggest that miR-4711-5p could be a promising target for CSC therapy.
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Affiliation(s)
- Yoshihiro Morimoto
- Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita city, Osaka, 565-0871, Japan
| | - Tsunekazu Mizushima
- Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita city, Osaka, 565-0871, Japan
| | - Xin Wu
- Department of Molecular Pathology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Yamadaoka 1-7, Suita city, Osaka, 565-0871, Japan
| | - Daisuke Okuzaki
- Genome Information Research Centre, Research Institute for Microbial Diseases, Osaka University, Yamadaoka 3-1, Suita city, Osaka, 565-0871, Japan
| | - Yuhki Yokoyama
- Department of Molecular Pathology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Yamadaoka 1-7, Suita city, Osaka, 565-0871, Japan
| | - Akira Inoue
- Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita city, Osaka, 565-0871, Japan
| | - Tsuyoshi Hata
- Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita city, Osaka, 565-0871, Japan
| | - Haruka Hirose
- Department of Molecular Pathology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Yamadaoka 1-7, Suita city, Osaka, 565-0871, Japan
| | - Yamin Qian
- Department of Molecular Pathology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Yamadaoka 1-7, Suita city, Osaka, 565-0871, Japan
| | - Jiaqi Wang
- Department of Molecular Pathology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Yamadaoka 1-7, Suita city, Osaka, 565-0871, Japan
| | - Norikatsu Miyoshi
- Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita city, Osaka, 565-0871, Japan
| | - Hidekazu Takahashi
- Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita city, Osaka, 565-0871, Japan
| | - Naotsugu Haraguchi
- Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita city, Osaka, 565-0871, Japan
| | - Chu Matsuda
- Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita city, Osaka, 565-0871, Japan
| | - Yuichiro Doki
- Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita city, Osaka, 565-0871, Japan
| | - Masaki Mori
- Department of Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka city, Fukuoka, 812-8582, Japan
| | - Hirofumi Yamamoto
- Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita city, Osaka, 565-0871, Japan. .,Department of Molecular Pathology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Yamadaoka 1-7, Suita city, Osaka, 565-0871, Japan.
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Knockdown of MCM10 Gene Impairs Glioblastoma Cell Proliferation, Migration and Invasion and the Implications for the Regulation of Tumorigenesis. J Mol Neurosci 2020; 70:759-768. [PMID: 32030558 DOI: 10.1007/s12031-020-01486-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 01/17/2020] [Indexed: 10/24/2022]
Abstract
Minichromosome maintenance 10 (MCM10) plays an important role in DNA replication and is expressed in a variety of tumors, including glioma. However, its role and mechanism in glioma remain elusive. The purpose of this study was to examine the molecular function of MCM10 in glioblastoma cell lines in vitro and to further investigate the molecular mechanisms in the network mediated by MCM10. Cell proliferation, invasion, and migration were investigated in the absence of MCM10 mediated by RNA interference (RNAi) in U87 and U251 cell lines. Microarray data were obtained from U87 cells infected with a lentivirus expressing a small interfering RNA (siRNA) targeting MCM10, and ingenuity pathway analysis (IPA) was performed. Molecular signaling pathways, gene functions, and upstream and downstream regulatory genes and networks were analyzed. MCM10 was positively stained in human glioblastoma multiforme (GBM) samples according to immunohistochemistry. Silencing MCM10 in U87 and U251 cells significantly reduced cell proliferation, migration, and invasion. In U87 cells transfected with MCM10, 274 genes were significantly upregulated, while 313 genes were downregulated. IPA revealed that MCM10 is involved in the IGF-1 signaling pathway, and calcitriol appears to be a significant upstream regulator of MCM10. Other factors, such as TWIST1 and Stat3, also interact within the MCM10-mediated network. Our data indicate that MCM10 is involved in the regulation of GBM in vitro and may provide more evidence for understanding the molecular mechanisms of this fatal disease.
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9
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Champeris Tsaniras S, Delinasios GJ, Petropoulos M, Panagopoulos A, Anagnostopoulos AK, Villiou M, Vlachakis D, Bravou V, Stathopoulos GT, Taraviras S. DNA Replication Inhibitor Geminin and Retinoic Acid Signaling Participate in Complex Interactions Associated With Pluripotency. Cancer Genomics Proteomics 2019; 16:593-601. [PMID: 31659113 PMCID: PMC6885373 DOI: 10.21873/cgp.20162] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 09/23/2019] [Accepted: 10/10/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND/AIM Several links between DNA replication, pluripotency and development have been recently identified. The involvement of miRNA in the regulation of cell cycle events and pluripotency factors has also gained attention. MATERIALS AND METHODS In the present study, we used the g:Profiler platform to analyze transcription factor binding sites, miRNA networks and protein-protein interactions to identify novel links among the aforementioned processes. RESULTS AND CONCLUSION A complex circuitry between retinoic acid signaling, SWI/SNF components, pluripotency factors including Oct4, Sox2 and Nanog and cell cycle regulators was identified. It is suggested that the DNA replication inhibitor geminin plays a central role in this circuitry.
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Affiliation(s)
- Spyridon Champeris Tsaniras
- Department of Physiology, Medical School, University of Patras, Patras, Greece
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, U.S.A
| | | | | | | | - Athanasios K Anagnostopoulos
- International Institute of Anticancer Research, Kapandriti, Greece
- Proteomics Research Unit, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Maria Villiou
- Department of Physiology, Medical School, University of Patras, Patras, Greece
| | - Dimitrios Vlachakis
- Bioinformatics & Medical Informatics Laboratory, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Vasiliki Bravou
- Department of Anatomy-Histology-Embryology, Faculty of Medicine, University of Patras, Patras, Greece
| | - Georgios T Stathopoulos
- Laboratory for Molecular Respiratory Carcinogenesis, Department of Physiology, Faculty of Medicine, University of Patras, Patras, Greece
| | - Stavros Taraviras
- Department of Physiology, Medical School, University of Patras, Patras, Greece
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10
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Mourikis TP, Benedetti L, Foxall E, Temelkovski D, Nulsen J, Perner J, Cereda M, Lagergren J, Howell M, Yau C, Fitzgerald RC, Scaffidi P, Ciccarelli FD. Patient-specific cancer genes contribute to recurrently perturbed pathways and establish therapeutic vulnerabilities in esophageal adenocarcinoma. Nat Commun 2019; 10:3101. [PMID: 31308377 PMCID: PMC6629660 DOI: 10.1038/s41467-019-10898-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 06/04/2019] [Indexed: 12/25/2022] Open
Abstract
The identification of cancer-promoting genetic alterations is challenging particularly in highly unstable and heterogeneous cancers, such as esophageal adenocarcinoma (EAC). Here we describe a machine learning algorithm to identify cancer genes in individual patients considering all types of damaging alterations simultaneously. Analysing 261 EACs from the OCCAMS Consortium, we discover helper genes that, alongside well-known drivers, promote cancer. We confirm the robustness of our approach in 107 additional EACs. Unlike recurrent alterations of known drivers, these cancer helper genes are rare or patient-specific. However, they converge towards perturbations of well-known cancer processes. Recurrence of the same process perturbations, rather than individual genes, divides EACs into six clusters differing in their molecular and clinical features. Experimentally mimicking the alterations of predicted helper genes in cancer and pre-cancer cells validates their contribution to disease progression, while reverting their alterations reveals EAC acquired dependencies that can be exploited in therapy.
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Affiliation(s)
- Thanos P Mourikis
- Cancer Systems Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
- School of Cancer and Pharmaceutical Sciences, King's College London, London, SE11UL, UK
| | - Lorena Benedetti
- Cancer Systems Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
- School of Cancer and Pharmaceutical Sciences, King's College London, London, SE11UL, UK
| | - Elizabeth Foxall
- Cancer Systems Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
- School of Cancer and Pharmaceutical Sciences, King's College London, London, SE11UL, UK
| | - Damjan Temelkovski
- Cancer Systems Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
- School of Cancer and Pharmaceutical Sciences, King's College London, London, SE11UL, UK
| | - Joel Nulsen
- Cancer Systems Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
- School of Cancer and Pharmaceutical Sciences, King's College London, London, SE11UL, UK
| | - Juliane Perner
- MRC Cancer Unit, Hutchison/MRC Research Centre, University of Cambridge, Cambridge, CB2 OXZ, UK
| | - Matteo Cereda
- Italian Institute for Genomic Medicine (IIGM), Turin, 10126, Italy
| | - Jesper Lagergren
- School of Cancer and Pharmaceutical Sciences, King's College London, London, SE11UL, UK
| | - Michael Howell
- High Throughput Screening Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | | | - Rebecca C Fitzgerald
- MRC Cancer Unit, Hutchison/MRC Research Centre, University of Cambridge, Cambridge, CB2 OXZ, UK
| | - Paola Scaffidi
- Cancer Epigenetics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
- UCL Cancer Institute, University College London, London, WC1E 6DD, UK
| | - Francesca D Ciccarelli
- Cancer Systems Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.
- School of Cancer and Pharmaceutical Sciences, King's College London, London, SE11UL, UK.
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11
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Sizek H, Hamel A, Deritei D, Campbell S, Ravasz Regan E. Boolean model of growth signaling, cell cycle and apoptosis predicts the molecular mechanism of aberrant cell cycle progression driven by hyperactive PI3K. PLoS Comput Biol 2019; 15:e1006402. [PMID: 30875364 PMCID: PMC6436762 DOI: 10.1371/journal.pcbi.1006402] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 03/27/2019] [Accepted: 02/12/2019] [Indexed: 02/07/2023] Open
Abstract
The PI3K/AKT signaling pathway plays a role in most cellular functions linked to cancer progression, including cell growth, proliferation, cell survival, tissue invasion and angiogenesis. It is generally recognized that hyperactive PI3K/AKT1 are oncogenic due to their boost to cell survival, cell cycle entry and growth-promoting metabolism. That said, the dynamics of PI3K and AKT1 during cell cycle progression are highly nonlinear. In addition to negative feedback that curtails their activity, protein expression of PI3K subunits has been shown to oscillate in dividing cells. The low-PI3K/low-AKT1 phase of these oscillations is required for cytokinesis, indicating that oncogenic PI3K may directly contribute to genome duplication. To explore this, we construct a Boolean model of growth factor signaling that can reproduce PI3K oscillations and link them to cell cycle progression and apoptosis. The resulting modular model reproduces hyperactive PI3K-driven cytokinesis failure and genome duplication and predicts the molecular drivers responsible for these failures by linking hyperactive PI3K to mis-regulation of Polo-like kinase 1 (Plk1) expression late in G2. To do this, our model captures the role of Plk1 in cell cycle progression and accurately reproduces multiple effects of its loss: G2 arrest, mitotic catastrophe, chromosome mis-segregation / aneuploidy due to premature anaphase, and cytokinesis failure leading to genome duplication, depending on the timing of Plk1 inhibition along the cell cycle. Finally, we offer testable predictions on the molecular drivers of PI3K oscillations, the timing of these oscillations with respect to division, and the role of altered Plk1 and FoxO activity in genome-level defects caused by hyperactive PI3K. Our model is an important starting point for the predictive modeling of cell fate decisions that include AKT1-driven senescence, as well as the non-intuitive effects of drugs that interfere with mitosis.
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Affiliation(s)
- Herbert Sizek
- Biochemistry and Molecular Biology, The College of Wooster, Wooster, OH, United States of America
| | - Andrew Hamel
- Biochemistry and Molecular Biology, The College of Wooster, Wooster, OH, United States of America
| | - Dávid Deritei
- Department of Physics, Pennsylvania State University, State College, PA, United States of America
- Department of Network and Data Science, Central European University, Budapest, Hungary
| | - Sarah Campbell
- Biochemistry and Molecular Biology, The College of Wooster, Wooster, OH, United States of America
| | - Erzsébet Ravasz Regan
- Biochemistry and Molecular Biology, The College of Wooster, Wooster, OH, United States of America
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12
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Mughal MJ, Mahadevappa R, Kwok HF. DNA replication licensing proteins: Saints and sinners in cancer. Semin Cancer Biol 2018; 58:11-21. [PMID: 30502375 DOI: 10.1016/j.semcancer.2018.11.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/08/2018] [Accepted: 11/26/2018] [Indexed: 12/12/2022]
Abstract
DNA replication is all-or-none process in the cell, meaning, once the DNA replication begins it proceeds to completion. Hence, to achieve maximum control of DNA replication, eukaryotic cells employ a multi-subunit initiator protein complex known as "pre-replication complex or DNA replication licensing complex (DNA replication LC). This complex involves multiple proteins which are origin-recognition complex family proteins, cell division cycle-6, chromatin licensing and DNA replication factor 1, and minichromosome maintenance family proteins. Higher-expression of DNA replication LC proteins appears to be an early event during development of cancer since it has been a common hallmark observed in a wide variety of cancers such as oesophageal, laryngeal, pulmonary, mammary, colorectal, renal, urothelial etc. However, the exact mechanisms leading to the abnormally high expression of DNA replication LC have not been clearly deciphered. Increased expression of DNA replication LC leads to licensing and/or firing of multiple origins thereby inducing replication stress and genomic instability. Therapeutic approaches where the reduction in the activity of DNA replication LC was achieved either by siRNA or shRNA techniques, have shown increased sensitivity of cancer cell lines towards the anti-cancer drugs such as cisplatin, 5-Fluorouracil, hydroxyurea etc. Thus, the expression level of DNA replication LC within the cell determines a cell's fate thereby creating a paradox where DNA replication LC acts as both "Saint" and "Sinner". With a potential to increase sensitivity to chemotherapy drugs, DNA replication LC proteins have prospective clinical importance in fighting cancer. Hence, in this review, we will shed light on importance of DNA replication LC with an aim to use DNA replication LC in diagnosis and prognosis of cancer in patients as well as possible therapeutic targets for cancer therapy.
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Affiliation(s)
- Muhammad Jameel Mughal
- Cancer Centre, Faculty of Health Sciences, University of Macau, Avenida de Universidade, Taipa, Macau
| | - Ravikiran Mahadevappa
- Cancer Centre, Faculty of Health Sciences, University of Macau, Avenida de Universidade, Taipa, Macau
| | - Hang Fai Kwok
- Cancer Centre, Faculty of Health Sciences, University of Macau, Avenida de Universidade, Taipa, Macau.
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13
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Aygun N, Altungoz O. MYCN is amplified during S phase, and c‑myb is involved in controlling MYCN expression and amplification in MYCN‑amplified neuroblastoma cell lines. Mol Med Rep 2018; 19:345-361. [PMID: 30483774 PMCID: PMC6297758 DOI: 10.3892/mmr.2018.9686] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 10/03/2018] [Indexed: 01/08/2023] Open
Abstract
Neuroblastoma derived from primitive sympathetic neural precursors is a common type of solid tumor in infants. MYCN proto-oncogene bHLH transcription factor (MYCN) amplification and 1p36 deletion are important factors associated with the poor prognosis of neuroblastoma. Expression levels of MYCN and c-MYB proto-oncogene transcription factor (c-myb) decline during the differentiation of neuroblastoma cells; E2F transcription factor 1 (E2F1) activates the MYCN promoter. However, the underlying mechanism of MYCN overexpression and amplification requires further investigation. In the present study, potential c-Myb target genes, and the effect of c-myb RNA interference (RNAi) on MYCN expression and amplification were investigated in MYCN-amplified neuroblastoma cell lines. The mRNA expression levels and MYCN gene copy number in five neuroblastoma cell lines were determined by quantitative polymerase chain reaction. In addition, variations in potential target gene expression and MYCN gene copy number between pre- and post-c-myb RNAi treatment groups in MYCN-amplified Kelly, IMR32, SIMA and MHH-NB-11 cell lines, normalized to those of non-MYCN-amplified SH-SY5Y, were examined. To determine the associations between gene expression levels and chromosomal aberrations, MYCN amplification and 1p36 alterations in interphases/metaphases were analyzed using fluorescence in situ hybridization. Statistical analyses revealed correlations between 1p36 alterations and the expression of c-myb, MYB proto-oncogene like 2 (B-myb) and cyclin dependent kinase inhibitor 1A (p21). Additionally, the results of the present study also demonstrated that c-myb may be associated with E2F1 and L3MBTL1 histone methyl-lysine binding protein (L3MBTL1) expression, and that E2F1 may contribute to MYCN, B-myb, p21 and chromatin licensing and DNA replication factor 1 (hCdt1) expression, but to the repression of geminin (GMNN). On c-myb RNAi treatment, L3MBTL1 expression was silenced, while GMNN was upregulated, indicating G2/M arrest. In addition, MYCN gene copy number increased following treatment with c-myb RNAi. Notably, the present study also reported a 43.545% sequence identity between upstream of MYCN and Drosophila melanogaster amplification control element 3, suggesting that expression and/or amplification mechanisms of developmentally-regulated genes may be evolutionarily conserved. In conclusion, c-myb may be associated with regulating MYCN expression and amplification. c-myb, B-myb and p21 may also serve a role against chromosome 1p aberrations. Together, it was concluded that MYCN gene is amplified during S phase, potentially via a replication-based mechanism.
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Affiliation(s)
- Nevim Aygun
- Department of Medical Biology, Faculty of Medicine, Dokuz Eylul University, Izmir 35340, Turkey
| | - Oguz Altungoz
- Department of Medical Biology, Faculty of Medicine, Dokuz Eylul University, Izmir 35340, Turkey
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14
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The Temporal Regulation of S Phase Proteins During G 1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1042:335-369. [PMID: 29357066 DOI: 10.1007/978-981-10-6955-0_16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Successful DNA replication requires intimate coordination with cell-cycle progression. Prior to DNA replication initiation in S phase, a series of essential preparatory events in G1 phase ensures timely, complete, and precise genome duplication. Among the essential molecular processes are regulated transcriptional upregulation of genes that encode replication proteins, appropriate post-transcriptional control of replication factor abundance and activity, and assembly of DNA-loaded protein complexes to license replication origins. In this chapter we describe these critical G1 events necessary for DNA replication and their regulation in the context of both cell-cycle entry and cell-cycle progression.
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15
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Takahashi A, Loo TM, Okada R, Kamachi F, Watanabe Y, Wakita M, Watanabe S, Kawamoto S, Miyata K, Barber GN, Ohtani N, Hara E. Downregulation of cytoplasmic DNases is implicated in cytoplasmic DNA accumulation and SASP in senescent cells. Nat Commun 2018; 9:1249. [PMID: 29593264 PMCID: PMC5871854 DOI: 10.1038/s41467-018-03555-8] [Citation(s) in RCA: 201] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 02/21/2018] [Indexed: 12/19/2022] Open
Abstract
Accumulating evidence indicates that the senescence-associated secretory phenotype (SASP) contributes to many aspects of physiology and disease. Thus, controlling the SASP will have tremendous impacts on our health. However, our understanding of SASP regulation is far from complete. Here, we show that cytoplasmic accumulation of nuclear DNA plays key roles in the onset of SASP. Although both DNase2 and TREX1 rapidly remove the cytoplasmic DNA fragments emanating from the nucleus in pre-senescent cells, the expression of these DNases is downregulated in senescent cells, resulting in the cytoplasmic accumulation of nuclear DNA. This causes the aberrant activation of cGAS-STING cytoplasmic DNA sensors, provoking SASP through induction of interferon-β. Notably, the blockage of this pathway prevents SASP in senescent hepatic stellate cells, accompanied by a decline of obesity-associated hepatocellular carcinoma development in mice. These findings provide valuable new insights into the roles and mechanisms of SASP and possibilities for their control. Activation of DNA damage response induces the acquisition of senescence-associated secretory phenotype (SASP) in senescent cells, but precise mechanisms remain unclear. Here, the authors show that the cytoplasmic accumulation of nuclear DNA activated cytoplasmic DNA sensors to provoke SASP.
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Affiliation(s)
- Akiko Takahashi
- The Cancer Institute, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, 135-8550, Japan.,PRESTO, JST, Kawaguchi, Saitama, 332-0012, Japan
| | - Tze Mun Loo
- The Cancer Institute, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, 135-8550, Japan.,Faculty of Science & Technology, Tokyo University of Science, Noda-shi, Chiba, 278-8510, Japan
| | - Ryo Okada
- The Cancer Institute, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, 135-8550, Japan
| | - Fumitaka Kamachi
- Faculty of Science & Technology, Tokyo University of Science, Noda-shi, Chiba, 278-8510, Japan
| | - Yoshihiro Watanabe
- Faculty of Science & Technology, Tokyo University of Science, Noda-shi, Chiba, 278-8510, Japan
| | - Masahiro Wakita
- Research Institute for Microbial Diseases, Osaka University, Suita-shi, Osaka, 565-0871, Japan
| | - Sugiko Watanabe
- Research Institute for Microbial Diseases, Osaka University, Suita-shi, Osaka, 565-0871, Japan
| | - Shimpei Kawamoto
- Research Institute for Microbial Diseases, Osaka University, Suita-shi, Osaka, 565-0871, Japan
| | - Kenichi Miyata
- The Cancer Institute, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, 135-8550, Japan
| | - Glen N Barber
- Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Naoko Ohtani
- Faculty of Science & Technology, Tokyo University of Science, Noda-shi, Chiba, 278-8510, Japan.,Graduate School of Medicine, Osaka City University, Abeno-ku, Osaka, 545-8585, Japan
| | - Eiji Hara
- The Cancer Institute, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, 135-8550, Japan. .,Research Institute for Microbial Diseases, Osaka University, Suita-shi, Osaka, 565-0871, Japan.
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16
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Arbi M, Pefani DE, Taraviras S, Lygerou Z. Controlling centriole numbers: Geminin family members as master regulators of centriole amplification and multiciliogenesis. Chromosoma 2017; 127:151-174. [PMID: 29243212 DOI: 10.1007/s00412-017-0652-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 11/06/2017] [Accepted: 11/07/2017] [Indexed: 01/18/2023]
Abstract
To ensure that the genetic material is accurately passed down to daughter cells during mitosis, dividing cells must duplicate their chromosomes and centrosomes once and only once per cell cycle. The same key steps-licensing, duplication, and segregation-control both the chromosome and the centrosome cycle, which must occur in concert to safeguard genome integrity. Aberrations in genome content or centrosome numbers lead to genomic instability and are linked to tumorigenesis. Such aberrations, however, can also be part of the normal life cycle of specific cell types. Multiciliated cells best exemplify the deviation from a normal centrosome cycle. They are post-mitotic cells which massively amplify their centrioles, bypassing the rule for once-per-cell-cycle centriole duplication. Hundreds of centrioles dock to the apical cell surface and generate motile cilia, whose concerted movement ensures fluid flow across epithelia. The early steps that control the generation of multiciliated cells have lately started to be elucidated. Geminin and the vertebrate-specific GemC1 and McIdas are distantly related coiled-coil proteins, initially identified as cell cycle regulators associated with the chromosome cycle. Geminin is required to ensure once-per-cell-cycle genome replication, while McIdas and GemC1 bind to Geminin and are implicated in DNA replication control. Recent findings highlight Geminin family members as early regulators of multiciliogenesis. GemC1 and McIdas specify the multiciliate cell fate by forming complexes with the E2F4/5 transcription factors to switch on a gene expression program leading to centriole amplification and cilia formation. Positive and negative interactions among Geminin family members may link cell cycle control to centriole amplification and multiciliogenesis, acting close to the point of transition from proliferation to differentiation. We review key steps of centrosome duplication and amplification, present the role of Geminin family members in the centrosome and chromosome cycle, and discuss links with disease.
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Affiliation(s)
- Marina Arbi
- Laboratory of Biology, School of Medicine, University of Patras, 26504 Rio, Patras, Greece
| | - Dafni-Eleftheria Pefani
- Laboratory of Biology, School of Medicine, University of Patras, 26504 Rio, Patras, Greece.,CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Stavros Taraviras
- Laboratory of Physiology, School of Medicine, University of Patras, 26504 Rio, Patras, Greece
| | - Zoi Lygerou
- Laboratory of Biology, School of Medicine, University of Patras, 26504 Rio, Patras, Greece.
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17
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Hosogane M, Bosu L, Fukumoto E, Yamada H, Sato S, Nakayama K. Geminin is an indispensable inhibitor of Cdt1 in mouse embryonic stem cells. Genes Cells 2017; 22:360-375. [DOI: 10.1111/gtc.12482] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/26/2017] [Indexed: 11/26/2022]
Affiliation(s)
- Masaki Hosogane
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Lena Bosu
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Emiko Fukumoto
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Hidetoshi Yamada
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Soichiro Sato
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Keiko Nakayama
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
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18
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Cyclin E Deregulation and Genomic Instability. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1042:527-547. [PMID: 29357072 DOI: 10.1007/978-981-10-6955-0_22] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Precise replication of genetic material and its equal distribution to daughter cells are essential to maintain genome stability. In eukaryotes, chromosome replication and segregation are temporally uncoupled, occurring in distinct intervals of the cell cycle, S and M phases, respectively. Cyclin E accumulates at the G1/S transition, where it promotes S phase entry and progression by binding to and activating CDK2. Several lines of evidence from different models indicate that cyclin E/CDK2 deregulation causes replication stress in S phase and chromosome segregation errors in M phase, leading to genomic instability and cancer. In this chapter, we will discuss the main findings that link cyclin E/CDK2 deregulation to genomic instability and the molecular mechanisms by which cyclin E/CDK2 induces replication stress and chromosome aberrations during carcinogenesis.
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19
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Pozo PN, Cook JG. Regulation and Function of Cdt1; A Key Factor in Cell Proliferation and Genome Stability. Genes (Basel) 2016; 8:genes8010002. [PMID: 28025526 PMCID: PMC5294997 DOI: 10.3390/genes8010002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 12/13/2016] [Accepted: 12/14/2016] [Indexed: 12/30/2022] Open
Abstract
Successful cell proliferation requires efficient and precise genome duplication followed by accurate chromosome segregation. The Cdc10-dependent transcript 1 protein (Cdt1) is required for the first step in DNA replication, and in human cells Cdt1 is also required during mitosis. Tight cell cycle controls over Cdt1 abundance and activity are critical to normal development and genome stability. We review here recent advances in elucidating Cdt1 molecular functions in both origin licensing and kinetochore–microtubule attachment, and we describe the current understanding of human Cdt1 regulation.
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Affiliation(s)
- Pedro N Pozo
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Jeanette Gowen Cook
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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20
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Transcriptional regulation of BMCC1 mediated by E2F1 in neuroblastoma cells. Biochem Biophys Res Commun 2016; 478:81-86. [DOI: 10.1016/j.bbrc.2016.07.089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 07/20/2016] [Indexed: 01/15/2023]
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21
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Ohno Y, Suzuki-Takedachi K, Yasunaga S, Kurogi T, Santo M, Masuhiro Y, Hanazawa S, Ohtsubo M, Naka K, Takihara Y. Manipulation of Cell Cycle and Chromatin Configuration by Means of Cell-Penetrating Geminin. PLoS One 2016; 11:e0155558. [PMID: 27195810 PMCID: PMC4873132 DOI: 10.1371/journal.pone.0155558] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/29/2016] [Indexed: 02/02/2023] Open
Abstract
Geminin regulates chromatin remodeling and DNA replication licensing which play an important role in regulating cellular proliferation and differentiation. Transcription of the Geminin gene is regulated via an E2F-responsive region, while the protein is being closely regulated by the ubiquitin-proteasome system. Our objective was to directly transduce Geminin protein into cells. Recombinant cell-penetrating Geminin (CP-Geminin) was generated by fusing Geminin with a membrane translocating motif from FGF4 and was efficiently incorporated into NIH 3T3 cells and mouse embryonic fibroblasts. The withdrawal study indicated that incorporated CP-Geminin was quickly reduced after removal from medium. We confirmed CP-Geminin was imported into the nucleus after incorporation and also that the incorporated CP-Geminin directly interacted with Cdt1 or Brahma/Brg1 as the same manner as Geminin. We further demonstrated that incorporated CP-Geminin suppressed S-phase progression of the cell cycle and reduced nuclease accessibility in the chromatin, probably through suppression of chromatin remodeling, indicating that CP-Geminin constitutes a novel tool for controlling chromatin configuration and the cell cycle. Since Geminin has been shown to be involved in regulation of stem cells and cancer cells, CP-Geminin is expected to be useful for elucidating the role of Geminin in stem cells and cancer cells, and for manipulating their activity.
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Affiliation(s)
- Yoshinori Ohno
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi, Minami-ku, Hiroshima, Japan
| | - Kyoko Suzuki-Takedachi
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi, Minami-ku, Hiroshima, Japan
| | - Shin’ichiro Yasunaga
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi, Minami-ku, Hiroshima, Japan
- Department of Biochemistry, Faculty of Medicine, Fukuoka University, Nanakuma, Jonan-ku, Fukuoka, Japan
| | - Toshiaki Kurogi
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi, Minami-ku, Hiroshima, Japan
| | - Mimoko Santo
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi, Minami-ku, Hiroshima, Japan
| | - Yoshikazu Masuhiro
- Department of Applied Biological Sciences, College of Bioresource Sciences, Nihon University, Kameino, Fujisawa-city, Kanagawa, Japan
| | - Shigemasa Hanazawa
- Department of Applied Biological Sciences, College of Bioresource Sciences, Nihon University, Kameino, Fujisawa-city, Kanagawa, Japan
| | - Motoaki Ohtsubo
- Department of Food and Fermentation Science, Faculty of Food Science and Nutrition, Beppu University, Kita-ishigaki 82, Beppu-city, Oita, Japan
| | - Kazuhito Naka
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi, Minami-ku, Hiroshima, Japan
| | - Yoshihiro Takihara
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi, Minami-ku, Hiroshima, Japan
- * E-mail:
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22
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Huang Y, Amin A, Qin Y, Wang Z, Jiang H, Liang L, Shi L, Liang C. A Role of hIPI3 in DNA Replication Licensing in Human Cells. PLoS One 2016; 11:e0151803. [PMID: 27057756 PMCID: PMC4825987 DOI: 10.1371/journal.pone.0151803] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/06/2016] [Indexed: 01/08/2023] Open
Abstract
The yeast Ipi3p is required for DNA replication and cell viability in Sacharomyces cerevisiae. It is an essential component of the Rix1 complex (Rix1p/Ipi2p-Ipi1p-Ipi3p) that is required for the processing of 35S pre-rRNA in pre-60S ribosomal particles and for the initiation of DNA replication. The human IPI3 homolog is WDR18 (WD repeat domain 18), which shares significant homology with yIpi3p. Here we report that knockdown of hIPI3 resulted in substantial defects in the chromatin association of the MCM complex, DNA replication, cell cycle progression and cell proliferation. Importantly, hIPI3 silencing did not result in a reduction of the protein level of hCDC6, hMCM7, or the ectopically expressed GFP protein, indicating that protein synthesis was not defective in the same time frame of the DNA replication and cell cycle defects. Furthermore, the mRNA and protein levels of hIPI3 fluctuate in the cell cycle, with the highest levels from M phase to early G1 phase, similar to other pre-replicative (pre-RC) proteins. Moreover, hIPI3 interacts with other replication-initiation proteins, co-localizes with hMCM7 in the nucleus, and is important for the nuclear localization of hMCM7. We also found that hIPI3 preferentially binds to the origins of DNA replication including those at the c-Myc, Lamin-B2 and β-Globin loci. These results indicate that hIPI3 is involved in human DNA replication licensing independent of its role in ribosome biogenesis.
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Affiliation(s)
- Yining Huang
- Biomedical Research Institute, Shenzhen-PKU-HKUST Medical Center, Shenzhen, China
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- HKUST Fok Ying Tung Research Institute, Guangzhou, China
| | - Aftab Amin
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Yan Qin
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Ziyi Wang
- Biomedical Research Institute, Shenzhen-PKU-HKUST Medical Center, Shenzhen, China
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- HKUST Fok Ying Tung Research Institute, Guangzhou, China
| | - Huadong Jiang
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Lu Liang
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Linjing Shi
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Chun Liang
- Biomedical Research Institute, Shenzhen-PKU-HKUST Medical Center, Shenzhen, China
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- HKUST Fok Ying Tung Research Institute, Guangzhou, China
- Intelgen Ltd., Hong Kong-Guangzhou-Foshan, China
- * E-mail:
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23
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Davaadelger B, Shen H, Maki CG. Novel roles for p53 in the genesis and targeting of tetraploid cancer cells. PLoS One 2014; 9:e110844. [PMID: 25380055 PMCID: PMC4224386 DOI: 10.1371/journal.pone.0110844] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/24/2014] [Indexed: 01/10/2023] Open
Abstract
Tetraploid (4N) cells are considered important in cancer because they can display increased tumorigenicity, resistance to conventional therapies, and are believed to be precursors to whole chromosome aneuploidy. It is therefore important to determine how tetraploid cancer cells arise, and how to target them. P53 is a tumor suppressor protein and key regulator of tetraploidy. As part of the “tetraploidy checkpoint”, p53 inhibits tetraploid cell proliferation by promoting a G1-arrest in incipient tetraploid cells (referred to as a tetraploid G1 arrest). Nutlin-3a is a preclinical drug that stabilizes p53 by blocking the interaction between p53 and MDM2. In the current study, Nutlin-3a promoted a p53-dependent tetraploid G1 arrest in two diploid clones of the HCT116 colon cancer cell line. Both clones underwent endoreduplication after Nutlin removal, giving rise to stable tetraploid clones that showed increased resistance to ionizing radiation (IR) and cisplatin (CP)-induced apoptosis compared to their diploid precursors. These findings demonstrate that transient p53 activation by Nutlin can promote tetraploid cell formation from diploid precursors, and the resulting tetraploid cells are therapy (IR/CP) resistant. Importantly, the tetraploid clones selected after Nutlin treatment expressed approximately twice as much P53 and MDM2 mRNA as diploid precursors, expressed approximately twice as many p53-MDM2 protein complexes (by co-immunoprecipitation), and were more susceptible to p53-dependent apoptosis and growth arrest induced by Nutlin. Based on these findings, we propose that p53 plays novel roles in both the formation and targeting of tetraploid cells. Specifically, we propose that 1) transient p53 activation can promote a tetraploid-G1 arrest and, as a result, may inadvertently promote formation of therapy-resistant tetraploid cells, and 2) therapy-resistant tetraploid cells, by virtue of having higher P53 gene copy number and expressing twice as many p53-MDM2 complexes, are more sensitive to apoptosis and/or growth arrest by anti-cancer MDM2 antagonists (e.g. Nutlin).
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Affiliation(s)
- Batzaya Davaadelger
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Hong Shen
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Carl G Maki
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, Illinois, United States of America
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Ohno Y, Saeki K, Yasunaga S, Kurogi T, Suzuki-Takedachi K, Shirai M, Mihara K, Yoshida K, Voncken JW, Ohtsubo M, Takihara Y. Transcription of the Geminin gene is regulated by a negative-feedback loop. Mol Biol Cell 2014; 25:1374-83. [PMID: 24554762 PMCID: PMC3983001 DOI: 10.1091/mbc.e13-09-0534] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Geminin transcription, regulated by E2Fs, is negatively regulated by Geminin through the inhibition of chromatin remodeling. Geminin transcription is thus regulated by a negative-feedback loop through the chromatin configuration. Homeostatically regulated Geminin may help couple regulation of DNA replication and transcription. Geminin performs a central function in regulating cellular proliferation and differentiation in development and also in stem cells. Of interest, down-regulation of Geminin induces gene transcription regulated by E2F, indicating that Geminin is involved in regulation of E2F-mediated transcriptional activity. Because transcription of the Geminin gene is reportedly regulated via an E2F-responsive region (E2F-R) located in the first intron, we first used a reporter vector to examine the effect of Geminin on E2F-mediated transcriptional regulation. We found that Geminin transfection suppressed E2F1- and E2F2-mediated transcriptional activation and also mildly suppressed such activity in synergy with E2F5, 6, and 7, suggesting that Geminin constitutes a negative-feedback loop for the Geminin promoter. Of interest, Geminin also suppressed nuclease accessibility, acetylation of histone H3, and trimethylation of histone H3 at lysine 4, which were induced by E2F1 overexpression, and enhanced trimethylation of histone H3 at lysine 27 and monoubiquitination of histone H2A at lysine 119 in E2F-R. However, Geminin5EQ, which does not interact with Brahma or Brg1, did not suppress accessibility to nuclease digestion or transcription but had an overall dominant-negative effect. These findings suggest that E2F-mediated activation of Geminin transcription is negatively regulated by Geminin through the inhibition of chromatin remodeling.
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Affiliation(s)
- Yoshinori Ohno
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan Department of Hematology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center Research Institute, Suita 562-0025, Japan Department of Life Sciences, Meiji University School of Agriculture, Kawasaki 214-8571, Japan Department of Molecular Genetics, Maastricht University Medical Centre, 6229ER Maastricht, Netherlands Department of Food and Fermentation Science, Faculty of Food Science and Nutrition, Beppu University, Beppu 874-0915, Japan
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25
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Cell cycle: mechanisms of control and dysregulation in cancer. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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26
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Transcriptional control of DNA replication licensing by Myc. Sci Rep 2013; 3:3444. [PMID: 24309437 PMCID: PMC3853707 DOI: 10.1038/srep03444] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 11/21/2013] [Indexed: 01/12/2023] Open
Abstract
The c-myc protooncogene encodes the Myc transcription factor, a global regulator of fundamental cellular processes. Deregulation of c-myc leads to tumorigenesis, and c-myc is an important driver in human cancer. Myc and its dimerization partner Max are bHLH-Zip DNA binding proteins involved in transcriptional regulation of target genes. Non-transcriptional functions have also been attributed to the Myc protein, notably direct interaction with the pre-replicative complex (pre-RC) controlling the initiation of DNA replication. A key component of the pre-RC is the Cdt1 protein, an essential factor in origin licensing. Here we present data suggesting that the CDT1 gene is a transcriptional target of the Myc-Max complex. Expression of the CDT1 gene in v-myc-transformed cells directly correlates with myc expression. Also, human tumor cells with elevated c-myc expression display increased CDT1 expression. Occupation of the CDT1 promoter by Myc-Max is demonstrated by chromatin immunoprecipitation, and transactivation by Myc-Max is shown in reporter assays. Ectopic expression of CDT1 leads to cell transformation. Our results provide a possible direct mechanistic link of Myc's canonical function as a transcription factor to DNA replication. Furthermore, we suggest that aberrant transcriptional activation of CDT1 by deregulated myc alleles contributes to the genomic instabilities observed in tumor cells.
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Dimaki M, Xouri G, Symeonidou IE, Sirinian C, Nishitani H, Taraviras S, Lygerou Z. Cell cycle-dependent subcellular translocation of the human DNA licensing inhibitor geminin. J Biol Chem 2013; 288:23953-63. [PMID: 23814078 DOI: 10.1074/jbc.m113.453092] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Once per cell cycle replication is crucial for maintaining genome integrity. Geminin interacts with the licensing factor Cdt1 to prevent untimely replication and is controlled by APC/C-dependent cell cycle specific proteolysis during mitosis and in G1. We show here that human geminin, when expressed in human cells in culture under a constitutive promoter, is excluded from the nucleus during part of the G1 phase and at the transition from G0 to G1. The N-terminal 30 amino acids of geminin, which contain its destruction box, are essential for nuclear exclusion. In addition, 30 amino acids within the central domain of geminin are required for both nuclear exclusion and nuclear accumulation. Cdt1 overexpression targets geminin to the nucleus, while reducing Cdt1 levels by RNAi leads to the appearance of endogenous geminin in the cytoplasm. Our data propose a novel means of regulating the balance of Cdt1/geminin in human cells, at the level of the subcellular localization of geminin.
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Affiliation(s)
- Maria Dimaki
- Laboratory of General Biology, School of Medicine, University of Patras, 26500 Rio, Patras, Greece
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Scmh1 has E3 ubiquitin ligase activity for geminin and histone H2A and regulates geminin stability directly or indirectly via transcriptional repression of Hoxa9 and Hoxb4. Mol Cell Biol 2012. [PMID: 23207902 DOI: 10.1128/mcb.00974-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Polycomb-group (PcG) complex 1 acts as an E3 ubiquitin ligase both for histone H2A to silence transcription and for geminin to regulate its stability. Scmh1 is a substoichiometric component of PcG complex 1 that provides the complex with an interaction domain for geminin. Scmh1 is unstable and regulated through the ubiquitin-proteasome system, but its molecular roles are unknown, so we generated Scmh1-deficient mice to elucidate its function. Loss of Scmh1 caused derepression of Hoxb4 and Hoxa9, direct targets of PcG complex 1-mediated transcriptional silencing in hematopoietic cells. Double knockdown of Hoxb4 and Hoxa9 or transduction of a dominant-negative Hoxb4N→A mutant caused geminin accumulation. Age-related transcriptional downregulation of derepressed Hoxa9 also leads to geminin accumulation. Transduction of Scmh1 lacking a geminin-binding domain restored derepressed expression of Hoxb4 and Hoxa9 but did not downregulate geminin like full-length Scmh1. Each of Hoxb4 and Hoxa9 can form a complex with Roc1-Ddb1-Cul4a to act as an E3 ubiquitin ligase for geminin. We suggest that geminin dysregulation may be restored by derepressed Hoxb4 and Hoxa9 in Scmh1-deficient mice. These findings suggest that PcG and a subset of Hox genes compose a homeostatic regulatory system for determining expression level of geminin.
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Abstract
Human papillomavirus (HPV) infection is necessary but not sufficient for cervical carcinogenesis. Genomic instability caused by HPV allows cells to acquire additional mutations required for malignant transformation. Genomic instability in the form of polyploidy has been demonstrated to play an important role in cervical carcinogenesis. We have recently found that HPV-16 E7 oncogene induces polyploidy in response to DNA damage; however, the mechanism is not known. Here we present evidence demonstrating that HPV-16 E7-expressing cells have an intact G(2) checkpoint. Upon DNA damage, HPV-16 E7-expressing cells arrest at the G(2) checkpoint and then undergo rereplication, a process of successive rounds of host DNA replication without entering mitosis. Interestingly, the DNA replication initiation factor Cdt1, whose uncontrolled expression induces rereplication in human cancer cells, is upregulated in E7-expressing cells. Moreover, downregulation of Cdt1 impairs the ability of E7 to induce rereplication. These results demonstrate an important role for Cdt1 in HPV E7-induced rereplication and shed light on mechanisms by which HPV induces genomic instability.
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Regulation of cell cycle progression by forkhead transcription factor FOXO3 through its binding partner DNA replication factor Cdt1. Proc Natl Acad Sci U S A 2012; 109:5717-22. [PMID: 22451935 DOI: 10.1073/pnas.1203210109] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To ensure genome stability, DNA must be replicated once and only once during each cell cycle. Cdt1 is tightly regulated to make sure that cells do not rereplicate their DNA. Multiple regulatory mechanisms operate to ensure degradation of Cdt1 in S phase. However, little is known about the positive regulators of Cdt1 under physiological conditions. Here we identify FOXO3 as a binding partner of Cdt1. FOXO3 forms a protein complex with Cdt1, which in turn blocks its interaction with DDB1 and PCNA. Conversely, FOXO3 depletion facilitated the proteolysis of Cdt1 in unperturbed cells. Intriguingly, FOXO3 deficiency resulted in impaired S-phase entry and reduced cell proliferation. We provide data that FOXO3 knockdown mimics Cdt1 down-regulation and affects G1/S transitions. Our results demonstrate a unique role of FOXO3 in binding to Cdt1 and maintaining its level required for cell cycle progression.
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31
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Abstract
ES cells proliferate with very short gap phases yet maintain their capacity to differentiate. It had been thought that the levels of cyclins and other substrates of ubiquitin ligase APC/C remain nearly constant and Cdk activity remains constitutively high in mouse ES cells. Here we demonstrate that APC/C (anaphase-promoting complex/cyclosome) enzyme is active in ES cells but attenuated by high levels of the Emi1 (early mitotic inhibitor-1) protein. Despite the presence of high Cdk activity during the G1 phase, chromatin can be effectively licensed for DNA replication and fast entry into the S phase can still occur. High Cdk activity during S-G2-M phases produces high levels of the DNA replication factor Cdt1, and this leads to efficient Mcm proteins loading on chromatin after mitotic exit. Although disturbing the usual balance between Cdk activity and APC/C activity found in somatic cells, a few key adaptations allow normal progression of a very rapid cell cycle.
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32
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Williams GH, Stoeber K. The cell cycle and cancer. J Pathol 2011; 226:352-64. [PMID: 21990031 DOI: 10.1002/path.3022] [Citation(s) in RCA: 445] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 09/30/2011] [Accepted: 10/01/2011] [Indexed: 12/25/2022]
Abstract
Deregulation of the cell cycle underlies the aberrant cell proliferation that characterizes cancer and loss of cell cycle checkpoint control promotes genetic instability. During the past two decades, cancer genetics has shown that hyperactivating mutations in growth signalling networks, coupled to loss of function of tumour suppressor proteins, drives oncogenic proliferation. Gene expression profiling of these complex and redundant mitogenic pathways to identify prognostic and predictive signatures and their therapeutic targeting has, however, proved challenging. The cell cycle machinery, which acts as an integration point for information transduced through upstream signalling networks, represents an alternative target for diagnostic and therapeutic interventions. Analysis of the DNA replication initiation machinery and mitotic engine proteins in human tissues is now leading to the identification of novel biomarkers for cancer detection and prognostication, and is providing target validation for cell cycle-directed therapies.
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Affiliation(s)
- Gareth H Williams
- Department of Pathology and Cancer Institute, University College London, UK.
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33
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Abstract
DNA replication is a highly regulated process involving a number of licensing and replication factors that function in a carefully orchestrated manner to faithfully replicate DNA during every cell cycle. Loss of proper licensing control leads to deregulated DNA replication including DNA re-replication, which can cause genome instability and tumorigenesis. Eukaryotic organisms have established several conserved mechanisms to prevent DNA re-replication and to counteract its potentially harmful effects. These mechanisms include tightly controlled regulation of licensing factors and activation of cell cycle and DNA damage checkpoints. Deregulated licensing control and its associated compromised checkpoints have both been observed in tumor cells, indicating that proper functioning of these pathways is essential for maintaining genome stability. In this review, we discuss the regulatory mechanisms of licensing control, the deleterious consequences when both licensing and checkpoints are compromised, and present possible mechanisms to prevent re-replication in order to maintain genome stability.
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Affiliation(s)
- Lan N Truong
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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34
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Fisher D. Control of DNA replication by cyclin-dependent kinases in development. Results Probl Cell Differ 2011; 53:201-17. [PMID: 21630147 DOI: 10.1007/978-3-642-19065-0_10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cyclin-dependent kinases (CDKs) are required for initiation of DNA replication in all eukaryotes, and appear to act at multiple levels to control replication origin firing, depending on the cell type and stage of development. In early development of many animals, both invertebrate and vertebrate, rapid cell cycling is coupled with transcriptional repression, and replication initiates at closely spaced replication origins with little or no sequence specificity. This organisation of DNA replication is modified during development as cell proliferation becomes more controlled and defined. In all eukaryotic cells, CDKs promote conversion of "licensed" pre-replication complexes (pre-RC) to active initiation complexes. In certain circumstances, CDKs may also control pre-RC formation, transcription of replication factor genes, chromatin remodelling, origin spacing, and organisation of replication origin clusters and replication foci within the nucleus. Although CDK1 and CDK2 have overlapping roles, there is a limit to their functional redundancy. Here, I review these findings and their implications for development.
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Affiliation(s)
- Daniel Fisher
- IGMM, CNRS UMR 5535, 1919 Route de Mende, 34293 Montpellier, France.
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35
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Hoxb4 transduction down-regulates Geminin protein, providing hematopoietic stem and progenitor cells with proliferation potential. Proc Natl Acad Sci U S A 2010; 107:21529-34. [PMID: 21098278 DOI: 10.1073/pnas.1011054107] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Retrovirus-mediated transduction of Hoxb4 enhances hematopoietic stem cell (HSC) activity and enforced expression of Hoxb4 induces in vitro development of HSCs from differentiating mouse embryonic stem cells, but the underlying molecular mechanism remains unclear. We previously showed that the HSC activity was abrogated by accumulated Geminin, an inhibitor for the DNA replication licensing factor Cdt1 in mice deficient in Rae28 (also known as Phc1), which encodes a member of Polycomb-group complex 1. In this study we found that Hoxb4 transduction reduced accumulated Geminin in Rae28-deficient mice, despite increasing the mRNA, and restored the impaired HSC activity. Supertransduction of Geminin suppressed the HSC activity induced by Hoxb4 transduction, whereas knockdown of Geminin promoted the clonogenic and replating activities, indicating the importance of Geminin regulation in the molecular mechanism underlying Hoxb4 transduction-mediated enhancement of the HSC activity. This facilitated our investigation of how transduced Hoxb4 reduced Geminin. We showed in vitro and in vivo that Hoxb4 and the Roc1 (also known as Rbx1)-Ddb1-Cul4a ubiquitin ligase core component formed a complex designated as RDCOXB4, which acted as an E3 ubiquitin ligase for Geminin and down-regulated Geminin through the ubiquitin-proteasome system. Down-regulated Geminin and the resultant E2F activation may provide cells with proliferation potential by increasing a DNA prereplicative complex loaded onto chromatin. Here we suggest that transduced Hoxb4 down-regulates Geminin protein probably by constituting the E3 ubiquitin ligase for Geminin to provide hematopoietic stem and progenitor cells with proliferation potential.
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van Duijn PW, Ziel-van der Made ACJ, van der Korput JAG, Trapman J. PTEN-mediated G1 cell-cycle arrest in LNCaP prostate cancer cells is associated with altered expression of cell-cycle regulators. Prostate 2010; 70:135-46. [PMID: 19784964 DOI: 10.1002/pros.21045] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND The tumor suppressor PTEN regulates many biological processes. A well-known downstream effector of PTEN is phospho-Akt. Although PTEN is the most frequently inactivated gene in prostate cancer, its mode of action is not fully understood. We studied the association of regulated PTEN expression with changes in biological function and gene expression profiles. METHODS PTEN-negative LNCaP cells were stably transfected with wild-type PTEN cDNA under inducible control, resulting in LNCaP/PTEN cells. Microarray analysis was used to monitor gene expression changes upon induction of PTEN. Expression of selected individual genes was studied in Q-PCR and siRNA experiments. Cell-cycle distribution was analyzed by flow cytometry. RESULTS Induced expression of PTEN in LNCaP/PTEN cells significantly inhibited cell proliferation, at least partly due to cell-cycle arrest at the G1 phase. Expression profiling combined with pathway analysis revealed that PTEN-dependent G1 growth arrest was associated with an altered mRNA expression of the G1 cell-cycle regulators Cdc25a, E2F2, cyclin G2, and RBL2/p130. Specific inhibition of Akt signaling by siRNA resulted in downregulation of both E2F2 and Cdc25a mRNA expression and upregulation of the FOXO target cyclin G2, similar to the effect observed by PTEN induction. However, Akt did not mediate the PTEN-dependent RBL2/p130 mRNA expression in LNCaP/PTEN cells. CONCLUSIONS The results indicate that PTEN dependent gene expression is important in cell-cycle regulation and is mediated by both Akt-dependent and -independent mechanisms.
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Affiliation(s)
- P W van Duijn
- Department of Pathology, Josephine Nefkens Institute, Erasmus University Medical Center, Rotterdam, the Netherlands
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37
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Cook JG. Replication licensing and the DNA damage checkpoint. Front Biosci (Landmark Ed) 2009; 14:5013-30. [PMID: 19482602 DOI: 10.2741/3584] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Accurate and timely duplication of chromosomal DNA requires that replication be coordinated with processes that ensure genome integrity. Significant advances in determining how the earliest steps in DNA replication are affected by DNA damage have highlighted some of the mechanisms to establish that coordination. Recent insights have expanded the relationship between the ATM and ATR-dependent checkpoint pathways and the proteins that bind and function at replication origins. These findings suggest that checkpoints and replication are more intimately associated than previously appreciated, even in the absence of exogenous DNA damage. This review summarizes some of these developments.
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Affiliation(s)
- Jeanette Gowen Cook
- Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center Campus Box 7260, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Tategu M, Nakagawa H, Sasaki K, Yamauchi R, Sekimachi S, Suita Y, Watanabe N, Yoshid K. Transcriptional regulation of human polo-like kinases and early mitotic inhibitor. J Genet Genomics 2009; 35:215-24. [PMID: 18439978 DOI: 10.1016/s1673-8527(08)60030-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Revised: 01/08/2008] [Accepted: 01/09/2008] [Indexed: 10/22/2022]
Abstract
Human polo-like kinases (PLK1-PLK4) have been implicated in mitotic regulation and carcinogenesis. PLK1 phosphorylates early mitotic inhibitor 1 (Emi1) to ensure mitosis entry, whereas Emi2 plays a key role during the meiotic cell cycle. Transcription factor E2F is primarily considered to regulate the G(1)/S transition of the cell cycle but its involvement in the regulation of mitosis has also been recently suggested. A gap still exists between the molecular basis of E2F and mitotic regulation. The present study was designed to characterize the transcriptional regulation of human PLK and Emi genes. Adenoviral overexpression of E2F1 increased PLK1 and PLK3 mRNA levels in A549 cells. A reporter gene assay revealed that the putative promoter regions of PLK1, PLK3, and PLK4 genes were responsive to activators E2F, E2F1-E2F3. We further characterized the putative promoter regions of Emi1 and Emi2 genes, and these could be regulated by activators E2F and E2F1-E2F4, respectively. Finally, PLK1-PLK4, Emi1, and Emi2 mRNA expression levels in human adult, fetal tissues, and several cell lines indicated that each gene has a unique expression pattern but is uniquely expressed in common tissues and cells such as the testes and thymus. Collectively, these results indicate that E2F can integrate G(1)/S and G(2)/M to oscillate the cell cycle by regulating mitotic genes PLK and Emi, leading to determination of the cell fate.
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Affiliation(s)
- Moe Tategu
- Department of Life Sciences, Meiji University School of Agriculture, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
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Li JN, Feng CJ, Lu YJ, Li HJ, Tu Z, Liao GQ, Liang C. mRNA expression of the DNA replication-initiation proteins in epithelial dysplasia and squamous cell carcinoma of the tongue. BMC Cancer 2008; 8:395. [PMID: 19116018 PMCID: PMC2648984 DOI: 10.1186/1471-2407-8-395] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2008] [Accepted: 12/30/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The tongue squamous cell carcinomas (SCCs) are characterized by high mitotic activity, and early detection is desirable. Overexpression of the DNA replication-initiation proteins has been associated with dysplasia and malignancy. Our aim was to determine whether these proteins are useful biomarkers for assessing the development of tongue SCC. METHODS We analyzed the mRNA expression of CDC6, CDT1, MCM2 and CDC45 in formalin-fixed, paraffin-embedded benign and malignant tongue tissues using quantitative real-time PCR followed by statistical analysis. RESULTS We found that the expression levels are significantly higher in malignant SCC than mild precancerous epithelial dysplasia, and the expression levels in general increase with increasing grade of precancerous lesions from mild, moderate to severe epithelial dysplasia. CDC6 and CDC45 expression is dependent of the dysplasia grade and lymph node status. CDT1 expression is higher in severe dysplasia than in mild and moderate dysplasia. MCM2 expression is dependent of the dysplasia grade, lymph node status and clinical stage. The expression of the four genes is independent of tumor size or histological grade. A simple linear regression analysis revealed a linear increase in the mRNA levels of the four genes from the mild to severe dysplasia and SCC. A strong association was established between CDC6 and CDT1, and between MCM2 and CDC45 expression. The nonparametric receiver operating characteristic analysis suggested that MCM2 and CDC45 had a higher accuracy than CDC6 and CDT1 for distinguishing dysplasia from tongue SCC. CONCLUSION These proteins can be used as biomarkers to distinguish precancerous dysplasia from SCC and are useful for early detection and diagnosis of SCC as an adjunct to clinicopathological parameters.
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Affiliation(s)
- Jian-na Li
- School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
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Specific activation of microRNA106b enables the p73 apoptotic response in chronic lymphocytic leukemia by targeting the ubiquitin ligase Itch for degradation. Blood 2008; 113:3744-53. [PMID: 19096009 DOI: 10.1182/blood-2008-09-178707] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Chronic lymphocytic leukemia (CLL) is characterized by cells that exhibit dysfunctional apoptosis. Here, we show that deacetylase inhibition led to the E2F1- and myc-mediated transcriptional activation of the microRNA miR106b in primary CLL cells. Induction of miR106b was associated with a down-regulation in the levels of the E3-ubiquitin ligase Itch. Decreases in Itch protein levels were associated with a reciprocal accumulation of its proapoptotic substrate, TAp73 (p73), and induction of p53 up-regulated modulator of apoptosis (PUMA) mRNA and protein. This event was accompanied by mitochondrial dysfunction, processing of caspase-9, and apoptosis of CLL cells. Ectopic expression of miR106b in CLL cells demonstrated that Itch was a direct target of miR106b such that miR106b-induced decreases in Itch resulted in an accumulation of p73. Thus, our results identify a novel regulatory mechanism wherein microRNA regulate cell survival by mediating the posttranscriptional down-regulation of an ubiquitin ligase, leading to the induction of a proapoptotic regulator in malignant cells. Silencing of miRNA expression in CLL may selectively suppress proapoptotic pathways, providing such tumors with a survival advantage. Consequently, chemotherapeutic drugs that activate miR106b could initiate a p53-independent mechanism that targets CLL cells.
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Salabat MR, Melstrom LG, Strouch MJ, Ding XZ, Milam BM, Ujiki MB, Chen C, Pelling JC, Rao S, Grippo PJ, McGarry TJ, Bentrem DJ. Geminin is overexpressed in human pancreatic cancer and downregulated by the bioflavanoid apigenin in pancreatic cancer cell lines. Mol Carcinog 2008; 47:835-44. [DOI: 10.1002/mc.20441] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Nakagawa H, Tategu M, Yamauchi R, Sasaki K, Sekimachi S, Yoshida K. Transcriptional regulation of an evolutionary conserved intergenic region of CDT2-INTS7. PLoS One 2008; 3:e1484. [PMID: 18213392 PMCID: PMC2194621 DOI: 10.1371/journal.pone.0001484] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2007] [Accepted: 12/18/2007] [Indexed: 11/24/2022] Open
Abstract
Background In the mammalian genome, a substantial number of gene pairs (approximately 10%) are arranged head-to-head on opposite strands within 1,000 base pairs, and separated by a bidirectional promoter(s) that generally drives the co-expression of both genes and results in functional coupling. The significance of unique genomic configuration remains elusive. Methodology/Principal Findings Here we report on the identification of an intergenic region of non-homologous genes, CDT2, a regulator of DNA replication, and an integrator complex subunit 7 (INTS7), an interactor of the largest subunit of RNA polymerase II. The CDT2-INTS7 intergenic region is 246 and 245 base pairs long in human and mouse respectively and is evolutionary well-conserved among several mammalian species. By measuring the luciferase activity in A549 cells, the intergenic human sequence was shown to be able to drive the reporter gene expression in either direction and notably, among transcription factors E2F, E2F1∼E2F4, but not E2F5 and E2F6, this sequence clearly up-regulated the reporter gene expression exclusively in the direction of the CDT2 gene. In contrast, B-Myb, c-Myb, and p53 down-regulated the reporter gene expression in the transcriptional direction of the INTS7 gene. Overexpression of E2F1 by adenoviral-mediated gene transfer resulted in an increased CDT2, but not INTS7, mRNA level. Real-time polymerase transcription (RT-PCR) analyses of the expression pattern for CDT2 and INTS7 mRNA in human adult and fetal tissues and cell lines revealed that transcription of these two genes are asymmetrically regulated. Moreover, the abundance of mRNA between mouse and rat tissues was similar, but these patterns were quite different from the results obtained from human tissues. Conclusions/Significance These findings add a unique example and help to understand the mechanistic insights into the regulation of gene expression through an evolutionary conserved intergenic region of the mammalian genome.
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Affiliation(s)
- Hiroki Nakagawa
- Department of Life Sciences, Meiji University School of Agriculture, Kawasaki, Kanagawa, Japan
| | - Moe Tategu
- Department of Life Sciences, Meiji University School of Agriculture, Kawasaki, Kanagawa, Japan
| | - Rieko Yamauchi
- Department of Life Sciences, Meiji University School of Agriculture, Kawasaki, Kanagawa, Japan
| | - Kaori Sasaki
- Department of Life Sciences, Meiji University School of Agriculture, Kawasaki, Kanagawa, Japan
| | - Sota Sekimachi
- Department of Life Sciences, Meiji University School of Agriculture, Kawasaki, Kanagawa, Japan
| | - Kenichi Yoshida
- Department of Life Sciences, Meiji University School of Agriculture, Kawasaki, Kanagawa, Japan
- * To whom correspondence should be addressed. E-mail:
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Liu E, Lee AYL, Chiba T, Olson E, Sun P, Wu X. The ATR-mediated S phase checkpoint prevents rereplication in mammalian cells when licensing control is disrupted. ACTA ACUST UNITED AC 2007; 179:643-57. [PMID: 18025301 PMCID: PMC2080923 DOI: 10.1083/jcb.200704138] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
DNA replication in eukaryotic cells is tightly controlled by a licensing mechanism, ensuring that each origin fires once and only once per cell cycle. We demonstrate that the ataxia telangiectasia and Rad3 related (ATR)–mediated S phase checkpoint acts as a surveillance mechanism to prevent rereplication. Thus, disruption of licensing control will not induce significant rereplication in mammalian cells when the ATR checkpoint is intact. We also demonstrate that single-stranded DNA (ssDNA) is the initial signal that activates the checkpoint when licensing control is compromised in mammalian cells. We demonstrate that uncontrolled DNA unwinding by minichromosome maintenance proteins upon Cdt1 overexpression is an important mechanism that leads to ssDNA accumulation and checkpoint activation. Furthermore, we show that replication protein A 2 and retinoblastoma protein are both downstream targets for ATR that are important for the inhibition of DNA rereplication. We reveal the molecular mechanisms by which the ATR-mediated S phase checkpoint pathway prevents DNA rereplication and thus significantly improve our understanding of how rereplication is prevented in mammalian cells.
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Affiliation(s)
- Enbo Liu
- Department of Molecular Experimental Medicine and 2Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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44
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Caro E, Gutierrez C. A green GEM: intriguing analogies with animal geminin. Trends Cell Biol 2007; 17:580-5. [PMID: 17997094 DOI: 10.1016/j.tcb.2007.09.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 09/21/2007] [Accepted: 09/24/2007] [Indexed: 01/16/2023]
Abstract
The transition of precursor cells from an undifferentiated proliferative state to differentiated cells with specific fates is of primary importance for multicellular organisms. Animals and plants have evolved two unrelated proteins, geminin and GEM, respectively, that play analogous roles in regulating this transition. These proteins are involved, probably in early G1 phase of the cell cycle, in regulating the expression of genes involved in cell fate and initiation of differentiation. They also interact with Cdt1, a component of the pre-replication complexes involved in DNA replication licensing in early G1 phase. The interaction of geminin and GEM with Cdt1 and transcriptional regulators is competitive, suggesting that these interactions can play a pivotal role in coordinating DNA replication, cell division and cell fate decisions.
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Affiliation(s)
- Elena Caro
- Centro de Biologia Molecular "Severo Ochoa", Consejo Superior de Investigaciones Cientificas, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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45
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Koppen A, Ait-Aissa R, Koster J, van Sluis PG, Ora I, Caron HN, Volckmann R, Versteeg R, Valentijn LJ. Direct regulation of the minichromosome maintenance complex by MYCN in neuroblastoma. Eur J Cancer 2007; 43:2413-22. [PMID: 17826980 DOI: 10.1016/j.ejca.2007.07.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Accepted: 07/18/2007] [Indexed: 12/23/2022]
Abstract
The c-Myc and MYCN oncogenes strongly induce cell proliferation. Although a limited series of cell cycle genes were found to be induced by the myc transcription factors, it is still unclear how they mediate the proliferative phenotype. We therefore analysed a neuroblastoma cell line with inducible MYCN expression. We found that all members of the minichromosome maintenance complex (MCM2-7) and MCM8 and MCM10 were up-regulated by MYCN. Expression profiling of 110 neuroblastoma tumours revealed that these genes strongly correlated with MYCN expression in vivo. Extensive chromatin immunoprecipitation experiments were performed to investigate whether the MCM genes were primary MYCN targets. MYCN was bound to the proximal promoters of the MCM2 to -8 genes. These data suggest that MYCN stimulates the expression of not only MCM7, which is a well defined MYCN target gene, but also of the complete minichromosome maintenance complex.
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Affiliation(s)
- Arjen Koppen
- Department of Human Genetics, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
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46
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Wang H, Larris B, Peiris TH, Zhang L, Le Lay J, Gao Y, Greenbaum LE. C/EBPbeta activates E2F-regulated genes in vivo via recruitment of the coactivator CREB-binding protein/P300. J Biol Chem 2007; 282:24679-88. [PMID: 17599912 DOI: 10.1074/jbc.m705066200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The E2F transcription factors play an essential role in regulating the G(1)- to S-phase transition of the cell cycle. Previous studies have identified the importance of interactions between E2Fs and other transcription factors as a mechanism for transcriptional control of a subset of E2F regulated target genes. However, the mechanisms responsible for E2F target gene specificity remain incompletely understood. Here we report that in a mammalian in vivo model of synchronized proliferation, C/EBPbeta occupancy on the promoters of E2F-regulated growth-related genes increases as a function of cell cycle progression. C/EPBbeta binding to these promoters is associated with recruitment of the coactivator CBP/p300, histone H4 acetylation, and maximal activation of E2F target genes. Moreover, binding of CBP/p300 to E2F targets is markedly reduced in C/EBPbeta null mice, resulting in reduced expression of E2F regulated genes. These findings identify C/EBPbeta as a direct activator of E2F target genes in mammalian cell cycle progression through a mechanism that involves recruitment of CBP/p300. The demonstration of a functional link between C/EBPbeta and CBP/p300 for E2F target gene activation provides a potential mechanism for how coactivators such as CBP/p300 can be selectively recruited to E2F target genes in response to tissue-specific growth stimuli.
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Affiliation(s)
- Haitao Wang
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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47
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Hayashi R, Goto Y, Tanaka R, Oonogi K, Hisasue M, Yoshida K. Transcriptional regulation of human chromatin assembly factor ASF1. DNA Cell Biol 2007; 26:91-9. [PMID: 17328667 DOI: 10.1089/dna.2006.0515] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Antisilencing function 1 (ASF1) is a conserved histone chaperone implicated in nucleosome assembly, transcriptional silencing, and the cellular response to DNA damage. Here, we report the identification of human ASF1B, but not ASF1A, as a direct transcriptional target of transcription factor E2F1. We demonstrated that overexpression of E2F1 by adenoviral-mediated gene transfer upregulated ASF1B mRNA expression in HeLa cells. Analysis of human ASF1B promoter constructs showed that an E2F-responsive sequence was necessary for E2F1-induced activation of the ASF1B gene transcription. Oligonucleotides including an E2F consensus sequence were specifically bound by E2F1 protein in vitro. Chromatin immunoprecipitation analysis demonstrated that E2F1 bound to an E2F-responsive sequence of the human ASF1B gene. Among the members of the E2F family, E2F1 to E2F5, but not E2F6, activated the ASF1B reporter construct. Sp1 and NFYA failed to induce the activity of the ASF1A and ASF1B promoter. ASF1A and ASF1B mRNA were upregulated by serum stimulation. Taken together, our results suggest that the expression of human ASF1A and ASF1B are upregulated followed by cell proliferation signal, but that of ASF1B is uniquely regulated by transcription factors E2F during cell cycle progression.
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Affiliation(s)
- Reiko Hayashi
- Department of Life Sciences, School of Agriculture, Meiji University, Kanagawa, Japan
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48
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Goto Y, Hayashi R, Kang D, Yoshida K. Acute loss of transcription factor E2F1 induces mitochondrial biogenesis in HeLa cells. J Cell Physiol 2007; 209:923-34. [PMID: 16972274 DOI: 10.1002/jcp.20802] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Here, we sought to clarify the comprehensive cellular response to transcription factor E2F1 expression using short interfering RNA (siRNA)-mediated gene silencing to examine the roles of E2F1. For this purpose, we analyzed global gene expression changes in E2F1 knockdown HeLa cells, where no changes in cell growth or apoptosis were observed. Among the identified genes, the mRNA levels of mitochondria-encoded genes were highly elevated in E2F1 siRNA-treated cells, but not in E2F6 siRNA-treated cells, relative to control siRNA-treated cells. These changes were accompanied by a significant increase in the transcription and replication of mitochondria DNA as well as the induction of nuclear-encoded mitochondrial topoisomerase I (TOP1MT) mRNA in E2F1 knockdown cells, but not in E2F6 knockdown cells, whereas the levels of nuclear-encoded mitochondrial transcription factor A (TFAM) mRNA and protein were unchanged, relative to the levels in control siRNA-treated cells. Time-course experiments demonstrated that the induction of TOP1MT coincided with the timing of E2F1 loss. In addition, E2F1 knockdown cells, but not E2F6 knockdown cells, displayed increased ATP levels along with an accumulation of cytochrome b protein. Finally, RNA interference (RNAi)-mediated reduction in E2F1 knockdown HeLa cells, but not in E2F6 knockdown HeLa cells, resulted in increased anticancer drug sensitivity. Taken together, these data demonstrate a novel physiological aspect of E2F1 in human cancer cells, where activated mitochondrial biogenesis occurs as a consequence of the acute loss of E2F1.
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Affiliation(s)
- Yuya Goto
- Department of Life Sciences, Meiji University Graduate School of Agriculture, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
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49
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Hayashi R, Arauchi T, Tategu M, Goto Y, Yoshida K. A combined computational and experimental study on the structure-regulation relationships of putative mammalian DNA replication initiator GINS. GENOMICS PROTEOMICS & BIOINFORMATICS 2007; 4:156-64. [PMID: 17127213 PMCID: PMC5054078 DOI: 10.1016/s1672-0229(06)60028-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
GINS, a heterotetramer of SLD5, PSF1, PSF2, and PSF3 proteins, is an emerging chromatin factor recognized to be involved in the initiation and elongation step of DNA replication. Although the yeast and Xenopus GINS genes are well documented, their orthologous genes in higher eukaryotes are not fully characterized. In this study, we report the genomic structure and transcriptional regulation of mammalian GINS genes. Serum stimulation increased the GINS mRNA levels in human cells. Reporter gene assay using putative GINS promoter sequences revealed that the expression of mammalian GINS is regulated by 17β-Estradiol-stimulated estrogen receptor α, and human PSF3 acts as a gene responsive to transcription factor E2F1. The goal of this study is to present the current data so as to encourage further work in the field of GINS gene regulation and functions in mammalian cells.
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50
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Tategu M, Arauchi T, Tanaka R, Nakagawa H, Yoshida K. Systems Biology-Based Identification of Crosstalk between E2F Transcription Factors and the Fanconi Anemia Pathway. GENE REGULATION AND SYSTEMS BIOLOGY 2007. [DOI: 10.1177/117762500700100001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Fanconi anemia (FA) is an autosomal recessive disorder characterized by congenital abnormalities, bone marrow failure, chromosome fragility, and cancer susceptibility. At least eleven members of the FA gene family have been identified using complementation experiments. Ubiquitin-proteasome has been shown to be a key regulator of FA proteins and their involvement in the repair of DNA damage. Here, we identified a novel functional link between the FA/BRCA pathway and E2F-mediated cell cycle regulome. In silico mining of a transcriptome database and promoter analyses revealed that a significant number of FA gene members were regulated by E2F transcription factors, known to be pivotal regulators of cell cycle progression – as previously described for BRCA1. Our findings suggest that E2Fs partly determine cell fate through the FA/BRCA pathway.
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Affiliation(s)
- Moe Tategu
- Department of Life Sciences, Meiji University School of Agriculture, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Takako Arauchi
- Department of Life Sciences, Meiji University School of Agriculture, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Rena Tanaka
- Department of Life Sciences, Meiji University School of Agriculture, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Hiroki Nakagawa
- Department of Life Sciences, Meiji University School of Agriculture, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Kenichi Yoshida
- Department of Life Sciences, Meiji University School of Agriculture, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
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