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Hermawan A, Ikawati M, Putri DDP, Fatimah N, Prasetio HH. Nobiletin Inhibits Breast Cancer Stem Cell by Regulating the Cell Cycle: A Comprehensive Bioinformatics Analysis and In Vitro Experiments. Nutr Cancer 2024; 76:638-655. [PMID: 38721626 DOI: 10.1080/01635581.2024.2348217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 04/18/2024] [Indexed: 07/02/2024]
Abstract
Inhibiting breast cancer stem cell (BCSC) signaling pathways is a strategic method for successfully treating breast cancer. Nobiletin (NOB) is a compound widely found in orange peel that exhibits a toxic effect on various types of cancer cells, and inhibits the signaling pathways that regulate the properties of BCSCs; however, the effects of NOB on BCSCs remain elusive. The purpose of this study was to determine the target genes of NOB for inhibiting BCSCs using in vitro three-dimensional breast cancer cell culture (mammospheres) and in silico approaches. We combined in vitro experiments to develop mammospheres and conducted cytotoxicity, next-generation sequencing, and bioinformatics analyses, such as gene ontology, the Reactome pathway enrichment, network topology, gene set enrichment analysis, hub genes selection, genetic alterations, prognostic value related to the mRNA expression, and mRNA and protein expression of potential NOB target genes that inhibit BCSCs. Here, we show that NOB inhibited BCSCs in mammospheres from MCF-7 cells. We also identified CDC6, CHEK1, BRCA1, UCHL5, TOP2A, MTMR4, and EXO1 as potential NOB targets inhibiting BCSCs. NOB decreased G0/G1, but increased the G2/M cell population. These findings showed that NOB is a potential therapeutic candidate for BCSCs treatment by regulating cell cycle.
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Affiliation(s)
- Adam Hermawan
- Laboratory of Macromolecular Engineering, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara II, Yogyakarta, Indonesia
- Cancer Chemoprevention Research Center, Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara II, Yogyakarta, Indonesia
- Laboratory of Advanced Pharmaceutical Sciences. APSLC Building, Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara II, Yogyakarta, Indonesia
| | - Muthi Ikawati
- Laboratory of Macromolecular Engineering, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara II, Yogyakarta, Indonesia
- Cancer Chemoprevention Research Center, Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara II, Yogyakarta, Indonesia
| | - Dyaningtyas Dewi Pamungkas Putri
- Cancer Chemoprevention Research Center, Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara II, Yogyakarta, Indonesia
- Laboratory of Advanced Pharmaceutical Sciences. APSLC Building, Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara II, Yogyakarta, Indonesia
- Laboratory of Pharmacology and Toxicology, Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara II, Yogyakarta, Indonesia
| | - Nurul Fatimah
- Laboratory of Advanced Pharmaceutical Sciences. APSLC Building, Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara II, Yogyakarta, Indonesia
| | - Heri Himawan Prasetio
- Laboratory of Macromolecular Engineering, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Universitas Gadjah Mada Sekip Utara II, Yogyakarta, Indonesia
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Shen M, Zhang Y, Tang L, Fu Q, Zhang J, Xu Y, Zeng H, Li Y. CDC6, a key replication licensing factor, is overexpressed and confers poor prognosis in diffuse large B-cell lymphoma. BMC Cancer 2023; 23:978. [PMID: 37833632 PMCID: PMC10571299 DOI: 10.1186/s12885-023-11186-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 07/17/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND Cell division cycle 6 (CDC6) is a key licensing factor in the assembly of pre-replicative complexes at origins of replication. The role of CDC6 in the pathogenesis of in diffuse larger B-cell lymphoma (DLBCL) remains unknown. We aim to investigate the effects of CDC6 on the proliferation, apoptosis and cell cycle regulation in DLBCL cells, delineate its underlying mechanism, and to correlate CDC6 expression with clinical characteristics and prognosis of patients with DLBCL. METHODS Initial bioinformatic analysis was performed to screen the potential role of CDC6 in DLBCL. Lentiviral constructs harboring CDC6 or shCDC6 was transfected to overexpress or knockdown CDC6 in SUDHL4 and OCI-LY7 cells. The cell proliferation was evaluated by CCK-8 assay, cell apoptosis was detected by Annexin-V APC/7-AAD double staining, and cell cycle was measured by flow cytometry. Real time quantitative PCR and western blot was used to characterize CDC6 expression and its downstream signaling pathways. The clinical data of DLBCL patients were retrospectively reviewed, the CDC6 expression in DLBCL or lymph node reactive hyperplasia tissues was evaluated by immunohistochemistry. RESULTS In silico data suggest that CDC6 overexpression is associated with inferior prognosis of DLBCL. We found that CDC6 overexpression increased SUDHL4 or OCI-LY7 cell proliferation, while knockdown of CDC6 inhibited cell proliferation in a time-dependent manner. Upon overexpression, CDC6 reduced cells in G1 phase and did not affect cell apoptosis; CDC6 knockdown led to significant cell cycle arrest in G1 phase and increase in cell apoptosis. Western blot showed that CDC6 inhibited the expression of INK4, E-Cadherin and ATR, accompanied by increased Bcl-2 and deceased Bax expression. The CDC6 protein was overexpressed DLBCL compared with lymph node reactive hyperplasia, and CDC6 overexpression was associated with non-GCB subtype, and conferred poor PFS and OS in patients with DLBCL. CONCLUSION CDC6 promotes cell proliferation and survival of DLBCL cells through regulation of G1/S cell cycle checkpoint and apoptosis. CDC6 is overexpressed and serves as a novel prognostic marker in DLBCL.
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Affiliation(s)
- Mingfang Shen
- Department of Hematology, the First Hospital of Jiaxing, 314001, Zhejiang, China
| | - Yunfeng Zhang
- Department of Hematology, the First Hospital of Jiaxing, 314001, Zhejiang, China
| | - Lun Tang
- Department of Hematology, the First Hospital of Jiaxing, 314001, Zhejiang, China
| | - Qinyan Fu
- Department of Hematology, the First Hospital of Jiaxing, 314001, Zhejiang, China
| | - Jiawei Zhang
- Department of Hematology, the Second Affiliated Hospital, Zhejiang University School of Medicine, 310009, Zhejiang, China
| | - Yang Xu
- Department of Hematology, the Second Affiliated Hospital, Zhejiang University School of Medicine, 310009, Zhejiang, China
| | - Hui Zeng
- Department of Hematology, the First Hospital of Jiaxing, 314001, Zhejiang, China.
| | - Yuan Li
- Department of Hematology, the First Hospital of Jiaxing, 314001, Zhejiang, China.
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Shen C, He Y, Chen Q, Feng H, Williams TM, Lu Y, He Z. Narrative review of emerging roles for AKT-mTOR signaling in cancer radioimmunotherapy. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1596. [PMID: 34790802 PMCID: PMC8576660 DOI: 10.21037/atm-21-4544] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/27/2021] [Indexed: 12/20/2022]
Abstract
Objective To summarize the roles of AKT-mTOR signaling in the regulation of the DNA damage response and PD-L1 expression in cancer cells, and propose a novel strategy of targeting AKT-mTOR signaling in combination with radioimmunotherapy in the era of cancer immunotherapy Background Immunotherapy has greatly improved the clinical outcomes of many cancer patients and has changed the landscape of cancer patient management. However, only a small subgroup of cancer patients (~20–30%) benefit from immune checkpoint blockade-based immunotherapy. The current challenge is to find biomarkers to predict the response of patients to immunotherapy and strategies to sensitize patients to immunotherapy. Methods Search and review the literature which were published in PUBMED from 2000–2021 with the key words mTOR, AKT, drug resistance, DNA damage response, immunotherapy, PD-L1, DNA repair, radioimmunotherapy. Conclusions More than 50% of cancer patients receive radiotherapy during their course of treatment. Radiotherapy has been shown to reduce the growth of locally irradiated tumors as well as metastatic non-irradiated tumors (abscopal effects) by affecting systemic immunity. Consistently, immunotherapy has been demonstrated to enhance radiotherapy with more than one hundred clinical trials of radiation in combination with immunotherapy (radioimmunotherapy) across cancer types. Nevertheless, current available data have shown limited efficacy of trials testing radioimmunotherapy. AKT-mTOR signaling is a major tumor growth-promoting pathway and is upregulated in most cancers. AKT-mTOR signaling is activated by growth factors as well as genotoxic stresses including radiotherapy. Importantly, recent advances have shown that AKT-mTOR is one of the main signaling pathways that regulate DNA damage repair as well as PD-L1 levels in cancers. These recent advances clearly suggest a novel cancer therapy strategy by targeting AKT-mTOR signaling in combination with radioimmunotherapy.
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Affiliation(s)
- Changxian Shen
- Department of Radiation Oncology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - Yuqi He
- Monash School of Medicine, Monash University, Clayton, VIC, Australia
| | - Qiang Chen
- Department of Oncology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Haihua Feng
- Department of Radiation Oncology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - Terence M Williams
- Department of Radiation Oncology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - Yuanzhi Lu
- Department of Clinical Pathology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Zhengfu He
- Department of Thoracic Surgery, Sir Run Run Shaw Hospital, College of Medicine Zhejiang University, Hangzhou, China
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He Z, Houghton PJ, Williams TM, Shen C. Regulation of DNA duplication by the mTOR signaling pathway. Cell Cycle 2021; 20:742-751. [PMID: 33691584 DOI: 10.1080/15384101.2021.1897271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Accurate and complete DNA replication and separation are essential for genetic information inheritance and organism maintenance. Errors in DNA duplication are the main source of genetic instability. Understanding DNA duplication regulation is the key to elucidate the mechanisms and find treatment strategies for human genetic disorders, especially cancer. The mechanistic target of rapamycin (mTOR) is a central regulator of cell growth and proliferation by integrating and processing extracellular and intracellular signals to monitor the well-being of cell physiology. mTOR signaling dysregulation is associated with many human diseases including cancer and diabetes. Emerging evidence has demonstrated that mTOR signaling plays a key role in DNA duplication. We herein review the current knowledge of mTOR signaling in the regulation of DNA replication origin licensing, replication fork progression, and stabilization.
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Affiliation(s)
- Zhengfu He
- Department of Thoracic Surgery, Sir Run Run Shaw Hospital, College of Medicine Zhejiang University, Hangzhou, China
| | - Peter J Houghton
- The Greehey Children's Cancer Research Institute, the University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Terence M Williams
- Department of Radiation Oncology, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, USA
| | - Changxian Shen
- Department of Radiation Oncology, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, USA
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Bostanabad SY, Noyan S, Dedeoglu BG, Gurdal H. Overexpression of β-Arrestins inhibits proliferation and motility in triple negative breast cancer cells. Sci Rep 2021; 11:1539. [PMID: 33452359 PMCID: PMC7810837 DOI: 10.1038/s41598-021-80974-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 12/31/2020] [Indexed: 01/29/2023] Open
Abstract
β-Arrestins (βArrs) are intracellular signal regulating proteins. Their expression level varies in some cancers and they have a significant impact on cancer cell function. In general, the significance of βArrs in cancer research comes from studies examining GPCR signalling. Given the diversity of different GPCR signals in cancer cell regulation, contradictory results are inevitable regarding the role of βArrs. Our approach examines the direct influence of βArrs on cellular function and gene expression profiles by changing their expression levels in breast cancer cells, MDA-MB-231 and MDA-MB-468. Reducing expression of βArr1 or βArr2 tended to increase cell proliferation and invasion whereas increasing their expression levels inhibited them. The overexpression of βArrs caused cell cycle S-phase arrest and differential expression of cell cycle genes, CDC45, BUB1, CCNB1, CCNB2, CDKN2C and reduced HER3, IGF-1R, and Snail. Regarding to the clinical relevance of our results, low expression levels of βArr1 were inversely correlated with CDC45, BUB1, CCNB1, and CCNB2 genes compared to normal tissue samples while positively correlated with poorer prognosis in breast tumours. These results indicate that βArr1 and βArr2 are significantly involved in cell cycle and anticancer signalling pathways through their influence on cell cycle genes and HER3, IGF-1R, and Snail in TNBC cells.
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Affiliation(s)
| | - Senem Noyan
- Biotechnology Institute of Ankara University, 06135, Ankara, Turkey
| | | | - Hakan Gurdal
- Department of Medical Pharmacology, Faculty of Medicine, University of Ankara, 06230, Ankara, Turkey.
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Gao L, Xia S, Zhang K, Lin C, He X, Zhang Y. Gene expression profile of THZ1-treated nasopharyngeal carcinoma cell lines indicates its involvement in the inhibition of the cell cycle. Transl Cancer Res 2021; 10:445-460. [PMID: 35116274 PMCID: PMC8799269 DOI: 10.21037/tcr-19-2888] [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: 12/20/2019] [Accepted: 09/30/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND The aim of this study was to identify downstream target genes and pathways regulated by THZ1 in nasopharyngeal carcinoma (NPC). METHODS The gene expression profile of GSE95750 in two NPC cell lines, untreated group and treated with THZ1 group, was analyzed. Differentially expressed genes (DEGs) were compared using the R-software. Then Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathways (KEGG) was analyzed using Database for Annotation, Visualization, and Integrated Discovery (DAVID). Cytoscape was used for protein-protein interaction (PPI) analysis. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to verified the gene expression. RESULTS We identified 25 genes with increased expression and 567 genes with decreased expression in THZ1-treated NPC cells. The top 10 significantly DEGs between untreated group and THZ1 treated group were identified by qRT-PCR and the results were in agreement with RNA-seq. The total 592 DEGs were found enriched in 1,148 GO terms and 38 KEGG pathways. The most important enriched pathways identified were cell cycle related, and several related node genes were identified, such as CDC6, CDC34, CDK7, CDK9, CCNA2, CCNB1, CDT1, KIF11, LIN9, PLK1, and POLR family, which consistent with RNA-seq. CONCLUSIONS Our results emphasize the differential genes and pathways occurring in THZ1-treated NPC cells, which increases our understanding of the anti-tumor mechanisms of THZ1.
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Affiliation(s)
- Lijuan Gao
- Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, China
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University, Guangzhou, China
- Department of Radiation Oncology, Cancer Center, Sun Yat-sen University, Guangzhou, China
| | - Shuang Xia
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Kunyi Zhang
- Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, China
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University, Guangzhou, China
- Department of Radiation Oncology, Cancer Center, Sun Yat-sen University, Guangzhou, China
| | - Chengguang Lin
- Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, China
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University, Guangzhou, China
- Department of Radiation Oncology, Cancer Center, Sun Yat-sen University, Guangzhou, China
| | - Xuyu He
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Ying Zhang
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
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Youn Y, Lee JC, Kim J, Kim JH, Hwang JH. Cdc6 disruption leads to centrosome abnormalities and chromosome instability in pancreatic cancer cells. Sci Rep 2020; 10:16518. [PMID: 33020506 PMCID: PMC7536414 DOI: 10.1038/s41598-020-73474-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022] Open
Abstract
Cell division cycle 6 (Cdc6) plays key roles in regulating DNA replication, and activation and maintenance of cell cycle check points. In addition, Cdc6 exerts oncogenic properties via genomic instability associated with incomplete DNA replication. This study aimed to examine the effects of Cdc6 on pancreatic cancer (PC) cells. Our results showed that Cdc6 expression was higher in clinical PC specimens (based on analysis of the GEPIA database) and cell lines, and the high Cdc6 expression was associated with poorer survival in The Cancer Genome Atlas-PC cohort. In addition, Cdc6-depleted PC cells significantly inhibited cell proliferation and colony formation, delayed G2/M cell cycle progression, and increased expression of p-histone H3 and cyclin A2 levels. These observations could be explained by Cdc6 depletion leading to multipolar and split spindles via centrosome amplification and microtubule disorganization which eventually increases chromosome missegregation. Furthermore, Cdc6-depleted PC cells showed significantly increased apoptosis, which was consistent with increased caspase-9 and caspase-3 activation. Collectively, our results demonstrated that Cdc6-depleted PC cells are arrested in mitosis and eventually undergo cell death by induced multipolar spindles, centrosome aberrations, microtubule disorganization, and chromosome instability. In conclusion, Cdc6 may be a potential biomarker and therapeutic target for PC.
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Affiliation(s)
- Yuna Youn
- Department of Internal Medicine, Seoul National University Bundang Hospital, Bundang-gu, Seongnam-si, Gyeonggi-do, 13620, Republic of Korea
| | - Jong-Chan Lee
- Department of Internal Medicine, Seoul National University Bundang Hospital, Bundang-gu, Seongnam-si, Gyeonggi-do, 13620, Republic of Korea.,Department of Internal Medicine, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Jaihwan Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Bundang-gu, Seongnam-si, Gyeonggi-do, 13620, Republic of Korea
| | - Jae Hyeong Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Bundang-gu, Seongnam-si, Gyeonggi-do, 13620, Republic of Korea.
| | - Jin-Hyeok Hwang
- Department of Internal Medicine, Seoul National University Bundang Hospital, Bundang-gu, Seongnam-si, Gyeonggi-do, 13620, Republic of Korea. .,Department of Internal Medicine, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea.
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Wu X, Li S, Hu X, Xiang X, Halloran M, Yang L, Williams TM, Houghton PJ, Shen C, He Z. mTOR Signaling Upregulates CDC6 via Suppressing miR-3178 and Promotes the Loading of DNA Replication Helicase. Sci Rep 2019; 9:9805. [PMID: 31285446 PMCID: PMC6614418 DOI: 10.1038/s41598-019-46052-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 06/21/2019] [Indexed: 12/12/2022] Open
Abstract
mTOR signaling pathway is deregulated in most cancers and uncontrolled cell cycle progression is a hallmark of cancer cell. However, the precise molecular mechanisms of the regulation of DNA replication and chromatin metabolism by mTOR signaling are largely unknown. We herein report that mTOR signaling promotes the loading of MCM2-7 helicase onto chromatin and upregulates DNA replication licensing factor CDC6. Pharmacological inhibition of mTOR kinase resulted in CHK1 checkpoint activation and decreased MCM2-7 replication helicase and PCNA associated with chromatins. Further pharmacological and genetic studies demonstrated CDC6 is positively controlled by mTORC1-S6K1 and mTORC2 signaling. miRNA screening revealed mTOR signaling suppresses miR-3178 thereby upregulating CDC6. Analysis of TCGA data found that CDC6 is overexpressed in most cancers and associates with the poor survival of cancer patients. Our findings suggest that mTOR signaling may control DNA replication origin licensing and replisome stability thereby cell cycle progression through CDC6 regulation.
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Affiliation(s)
- Xianjin Wu
- Key Laboratory of Hunan Province for Study and Utilization of Ethnic Medicinal Plant Resources, College of Biological and Food Engineering, Huaihua University, Huaihua, 418008, China
| | - Shenghua Li
- Key Laboratory of Hunan Province for Study and Utilization of Ethnic Medicinal Plant Resources, College of Biological and Food Engineering, Huaihua University, Huaihua, 418008, China
| | - Xing Hu
- Key Laboratory of Hunan Province for Study and Utilization of Ethnic Medicinal Plant Resources, College of Biological and Food Engineering, Huaihua University, Huaihua, 418008, China
| | - Xiaoliang Xiang
- Key Laboratory of Hunan Province for Study and Utilization of Ethnic Medicinal Plant Resources, College of Biological and Food Engineering, Huaihua University, Huaihua, 418008, China
| | - Megan Halloran
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Linlin Yang
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Terence M Williams
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Peter J Houghton
- The Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, 78229, USA
| | - Changxian Shen
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, 43210, USA.
| | - Zhengfu He
- Department of Thoracic Surgery, Sir Run Run Shaw Hospital, College of Medicine Zhejiang University, Hangzhou, 310016, China.
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Jiang W, Yu Y, Liu J, Zhao Q, Wang J, Zhang J, Dang X. Downregulation of Cdc6 inhibits tumorigenesis of osteosarcoma in vivo and in vitro. Biomed Pharmacother 2019; 115:108949. [DOI: 10.1016/j.biopha.2019.108949] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/29/2019] [Accepted: 05/01/2019] [Indexed: 02/06/2023] Open
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Kao SH, Wu HT, Wu KJ. Ubiquitination by HUWE1 in tumorigenesis and beyond. J Biomed Sci 2018; 25:67. [PMID: 30176860 PMCID: PMC6122628 DOI: 10.1186/s12929-018-0470-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 08/28/2018] [Indexed: 01/19/2023] Open
Abstract
Ubiquitination modulates a large repertoire of cellular functions and thus, dysregulation of the ubiquitin system results in multiple human diseases, including cancer. Ubiquitination requires an E3 ligase, which is responsible for substrate recognition and conferring specificity to ubiquitination. HUWE1 is a multifaceted HECT domain-containing ubiquitin E3 ligase, which catalyzes both mono-ubiquitination and K6-, K48- and K63-linked poly-ubiquitination of its substrates. Many of the substrates of HUWE1 play a crucial role in maintaining the homeostasis of cellular development. Not surprisingly, dysregulation of HUWE1 is associated with tumorigenesis and metastasis. HUWE1 is frequently overexpressed in solid tumors, but can be downregulated in brain tumors, suggesting that HUWE1 may possess differing cell-specific functions depending on the downstream targets of HUWE1. This review introduces some important discoveries of the HUWE1 substrates, including those controlling proliferation and differentiation, apoptosis, DNA repair, and responses to stress. In addition, we review the signaling pathways HUWE1 participates in and obstacles to the identification of HUWE1 substrates. We also discuss up-to-date potential therapeutic designs using small molecules or ubiquitin variants (UbV) against the HUWE1 activity. These molecular advances provide a translational platform for future bench-to-bed studies. HUWE1 is a critical ubiquitination modulator during the tumor progression and may serve as a possible therapeutic target for cancer treatment.
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Affiliation(s)
- Shih-Han Kao
- Research Center for Tumor Medical Science, China Medical University, No. 91, Hseuh-Shih Rd, Taichung, 40402, Taiwan. .,Drug Development Center, China Medical University, Taichung, 40402, Taiwan.
| | - Han-Tsang Wu
- Department of Cell and Tissue Engineering, Changhua Christian Hospital, Changhua City, 500, Taiwan
| | - Kou-Juey Wu
- Research Center for Tumor Medical Science, China Medical University, No. 91, Hseuh-Shih Rd, Taichung, 40402, Taiwan. .,Drug Development Center, China Medical University, Taichung, 40402, Taiwan. .,Institute of New Drug Development, Taichung, 40402, Taiwan. .,Graduate Institutes of Biomedical Sciences, China Medical University, Taichung, 40402, Taiwan. .,Departmet of Medical Research, China Medical University Hospital, Taichung, 40402, Taiwan.
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Saritha VN, Veena VS, Jagathnath Krishna KM, Somanathan T, Sujathan K. Significance of DNA Replication Licensing Proteins (MCM2, MCM5 and CDC6), p16 and p63 as Markers of Premalignant Lesions of the Uterine Cervix: Its Usefulness to Predict Malignant Potential. Asian Pac J Cancer Prev 2018; 19:141-148. [PMID: 29373905 PMCID: PMC5844608 DOI: 10.22034/apjcp.2018.19.1.141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Cervical cancer continues to be a leading cancer among women in many parts of the world. Nation-wide screening
with the Pap smear has not been implemented in India due to the lack of adequately trained cytologists. Identification
of biomarkers to predict malignant potential of the identified low risk lesions is essential to avoid excessive retesting
and follow up. The current study analyzed the expression patterns of DNA replication licensing proteins, proliferation
inhibitor protein p16INK4A and tumor suppresser protein p63 in cervical tissues and smears to assess the ability of
these proteins to predict progression. Methods: Cervical smears and corresponding tissues were immunostained using
mouse monoclonal antibodies against MCM2, MCM5, CDC6, p16 and p63. Smears were treated with a non-ionic
surfactant sodium deoxycholate prior to immuno-cytochemistry. The standard ABC method of immunohistochemistry
was performed using DAB as the chromogen. The immunostained samples were scored on a 0-3+ scale and staining
patterns of smears were compared with those of tissue sections. Sensitivity and specificity for each of these markers were
calculated taking histopathology as the gold standard. Result: All the markers were positive in malignant and dysplastic
cells. MCM protein expression was found to be up-regulated in LSIL, HSIL and in malignancies to a greater extent
than p16 as well as p63. CDC6 protein was preferentially expressed in high grade lesions and in invasive squamous
cell carcinomas. A progressive increase in the expression of DNA replication licensing proteins in accordance with
the grades of cervical intraepithelial lesion suggests these markers as significant to predict malignant potential of low
grade lesions in cervical smears. Conclusion: MCMs and CDC6 can be applied as biomarkers to predict malignant
potential of low grade lesions identified in screening programmes and retesting / follow up might be confined to those
with high risk lesions alone so that overuse of resources can be safely avoided.
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Affiliation(s)
- V N Saritha
- Division of Cancer Research, , Regional Cancer Centre,Trivandrum, Kerla, India.
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Chen S, Chen X, Xie G, He Y, Yan D, Zheng D, Li S, Fu X, Li Y, Pang X, Hu Z, Li H, Tan W, Li J. Cdc6 contributes to cisplatin-resistance by activation of ATR-Chk1 pathway in bladder cancer cells. Oncotarget 2018; 7:40362-40376. [PMID: 27246979 PMCID: PMC5130013 DOI: 10.18632/oncotarget.9616] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/08/2016] [Indexed: 12/22/2022] Open
Abstract
High activation of DNA damage response is implicated in cisplatin (CDDP) resistance which presents as a serious obstacle for bladder cancer treatment. Cdc6 plays an important role in the malignant progression of tumor. Here, we reported that Cdc6 expression is up-regulated in bladder cancer tissues and is positively correlated to high tumor grade. Cdc6 depletion can attenuate the malignant properties of bladder cancer cells, including DNA replication, migration and invasion. Furthermore, higher levels of chromatin-binding Cdc6 and ATR were detected in CDDP-resistant bladder cancer cells than in the parent bladder cancer cells. Intriguingly, down-regulation of Cdc6 can enhance sensitivity to CDDP both in bladder cancer cells and CDDP-resistant bladder cancer cells. Cdc6 depletion abrogates S phase arrest caused by CDDP, leading to aberrant mitosis by inactivating ATR-Chk1-Cdc25C pathway. Our results indicate that Cdc6 may be a promising target for overcoming CDDP resistance in bladder cancer.
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Affiliation(s)
- Sansan Chen
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China.,Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Xinglu Chen
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Gui'e Xie
- KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Yue He
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Daoyu Yan
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Dianpeng Zheng
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Shi Li
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Xinyang Fu
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Yeping Li
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Xiang Pang
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Zhiming Hu
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Hongwei Li
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Wanlong Tan
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Jinlong Li
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
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13
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Karanika S, Karantanos T, Li L, Wang J, Park S, Yang G, Zuo X, Song JH, Maity SN, Manyam GC, Broom B, Aparicio AM, Gallick GE, Troncoso P, Corn PG, Navone N, Zhang W, Li S, Thompson TC. Targeting DNA Damage Response in Prostate Cancer by Inhibiting Androgen Receptor-CDC6-ATR-Chk1 Signaling. Cell Rep 2017; 18:1970-1981. [PMID: 28228262 DOI: 10.1016/j.celrep.2017.01.072] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 11/11/2016] [Accepted: 01/26/2017] [Indexed: 01/01/2023] Open
Abstract
Cell division cycle 6 (CDC6), an androgen receptor (AR) target gene, is implicated in regulating DNA replication and checkpoint mechanisms. CDC6 expression is increased during prostate cancer (PCa) progression and positively correlates with AR in PCa tissues. AR or CDC6 knockdown, together with AZD7762, a Chk1/2 inhibitor, results in decreased TopBP1-ATR-Chk1 signaling and markedly increased ataxia-telangiectasia-mutated (ATM) phosphorylation, a biomarker of DNA damage, and synergistically increases treatment efficacy. Combination treatment with the AR signaling inhibitor enzalutamide (ENZ) and the Chk1/2 inhibitor AZD7762 demonstrates synergy with regard to inhibition of AR-CDC6-ATR-Chk1 signaling, ATM phosphorylation induction, and apoptosis in VCaP (mutant p53) and LNCaP-C4-2b (wild-type p53) cells. CDC6 overexpression significantly reduced ENZ- and AZD7762-induced apoptosis. Additive or synergistic therapeutic activities are demonstrated in AR-positive animal xenograft models. These findings have important clinical implications, since they introduce a therapeutic strategy for AR-positive, metastatic, castration-resistant PCa, regardless of p53 status, through targeting AR-CDC6-ATR-Chk1 signaling.
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Affiliation(s)
- Styliani Karanika
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Theodoros Karantanos
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Likun Li
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jianxiang Wang
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Sanghee Park
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Guang Yang
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xuemei Zuo
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jian H Song
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Sankar N Maity
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ganiraju C Manyam
- Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Bradley Broom
- Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Ana M Aparicio
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Gary E Gallick
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Patricia Troncoso
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Paul G Corn
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Nora Navone
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Wei Zhang
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Shuhua Li
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Timothy C Thompson
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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14
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Zhang JH, He YL, Zhu R, Du W, Xiao JH. Deregulated expression of Cdc6 as BCR/ABL-dependent survival factor in chronic myeloid leukemia cells. Tumour Biol 2017. [PMID: 28639894 DOI: 10.1177/1010428317713394] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Chronic myeloid leukemia is characterized by the presence of the reciprocal translocation t(9;22) and the BCR/ABL oncogene. The BCR/ABL oncogene activates multiple signaling pathways and involves the dysregulation of oncogenes during the progression of chronic myeloid leukemia. The cell division cycle protein 6, an essential regulator of DNA replication, is elevated in some human cancer cells. However, the expression of cell division cycle protein 6 in chronic myeloid leukemia and the underlying regulatory mechanism remain to be elucidated. In this study, our data showed that cell division cycle protein 6 expression was significantly upregulated in primary chronic myeloid leukemia cells and the chronic myeloid leukemia cell line K562 cells, as compared to the normal bone marrow mononuclear cells. BCR/ABL kinase inhibitor STI571 or BCR/ABL small interfering RNA could significantly downregulate cell division cycle protein 6 messenger RNA expression in K562 cells. Moreover, phosphoinositide 3-kinase/AKT pathway inhibitor LY294002 and Janus kinase/signal transducer and activator of transcription pathway inhibitor AG490 could downregulate cell division cycle protein 6 expression in K562 cells, but not RAS/mitogen-activated protein kinase pathway inhibitor PD98059 had such effect. Cell division cycle protein 6 gene silencing by small interfering RNA effectively resulted in decrease of proliferation, increase of apoptosis, and arrest of cell cycle in K562 cells. These findings have demonstrated that cell division cycle protein 6 overexpression may contribute to the high proliferation and low apoptosis in chronic myeloid leukemia cells and can be regulated by BCR/ABL signal transduction through downstream phosphoinositide 3-kinase/Akt and Janus kinase/signal transducer and activator of transcription pathways, suggesting cell division cycle protein 6 as a potential therapeutic target in chronic myeloid leukemia.
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Affiliation(s)
- Jia-Hua Zhang
- 1 Center for Stem Cell Research and Application, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Yan-Li He
- 1 Center for Stem Cell Research and Application, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Rui Zhu
- 2 Department of Integrated Chinese and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Wen Du
- 1 Center for Stem Cell Research and Application, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Jun-Hua Xiao
- 3 Department of Pharmacology, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
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15
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Role of Cdc6 During Oogenesis and Early Embryo Development in Mouse and Xenopus laevis. Results Probl Cell Differ 2017; 59:201-211. [PMID: 28247050 DOI: 10.1007/978-3-319-44820-6_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cdc6 is an important player in cell cycle regulation. It is involved in the regulation of both S-phase and M-phase. Its role during oogenesis is crucial for repression of the S-phase between the first and the second meiotic M-phases, and it also regulates, via CDK1 inhibition, the M-phase entry and exit. This is of special importance for the reactivation of the major M-phase-regulating kinase CDK1 (Cyclin-Dependent Kinase 1) in oocytes entering metaphase II of meiosis and in embryo cleavage divisions, in which precise timing allows coordination between cell cycle events and developmental program of the embryo. In this chapter, we discuss the role of Cdc6 protein in oocytes and early embryos.
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16
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Kramer D, Stark N, Schulz-Heddergott R, Erytch N, Edmunds S, Roßmann L, Bastians H, Concin N, Moll UM, Dobbelstein M. Strong antitumor synergy between DNA crosslinking and HSP90 inhibition causes massive premitotic DNA fragmentation in ovarian cancer cells. Cell Death Differ 2016; 24:300-316. [PMID: 27834954 DOI: 10.1038/cdd.2016.124] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 08/13/2016] [Accepted: 09/26/2016] [Indexed: 12/29/2022] Open
Abstract
All current regimens for treating ovarian cancer center around carboplatin as standard first line. The HSP90 inhibitor ganetespib is currently being assessed in advanced clinical oncology trials. Thus, we tested the combined effects of ganetespib and carboplatin on a panel of 15 human ovarian cancer lines. Strikingly, the two drugs strongly synergized in cytotoxicity in tumor cells lacking wild-type p53. Mechanistically, ganetespib and carboplatin in combination, but not individually, induced persistent DNA damage causing massive global chromosome fragmentation. Live-cell microscopy revealed chromosome fragmentation occurring to a dramatic degree when cells condensed their chromatin in preparation for mitosis, followed by cell death in mitosis or upon aberrant exit from mitosis. HSP90 inhibition caused the rapid decay of key components of the Fanconi anemia pathway required for repair of carboplatin-induced interstrand crosslinks (ICLs), as well as of cell cycle checkpoint mediators. Overexpressing FancA rescued the DNA damage induced by the drug combination, indicating that FancA is indeed a key client of Hsp90 that enables cancer cell survival in the presence of ICLs. Conversely, depletion of nuclease DNA2 prevented chromosomal fragmentation, pointing to an imbalance of defective repair in the face of uncontrolled nuclease activity as mechanistic basis for the observed premitotic DNA fragmentation. Importantly, the drug combination induced robust antitumor activity in xenograft models, again accompanied with depletion of FancA. In sum, our findings indicate that ganetespib strongly potentiates the antitumor efficacy of carboplatin by causing combined inhibition of DNA repair and cell cycle control mechanisms, thus triggering global chromosome disruption, aberrant mitosis and cell death.
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Affiliation(s)
- Daniela Kramer
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen D-37077, Germany
| | - Nadine Stark
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen D-37077, Germany
| | - Ramona Schulz-Heddergott
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen D-37077, Germany
| | - Norman Erytch
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen D-37077, Germany
| | - Shelley Edmunds
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen D-37077, Germany
| | - Laura Roßmann
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen D-37077, Germany
| | - Holger Bastians
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen D-37077, Germany
| | - Nicole Concin
- Department of Obstetrics and Gynaecology, Medical University of Innsbruck, Innsbruck, Austria
| | - Ute M Moll
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen D-37077, Germany.,Department of Pathology, School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Matthias Dobbelstein
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen D-37077, Germany
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17
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Tudzarova S, Mulholland P, Dey A, Stoeber K, Okorokov AL, Williams GH. p53 controls CDC7 levels to reinforce G1 cell cycle arrest upon genotoxic stress. Cell Cycle 2016; 15:2958-2972. [PMID: 27611229 PMCID: PMC5105930 DOI: 10.1080/15384101.2016.1231281] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
DNA replication initiation is a key event in the cell cycle, which is dependent on 2 kinases - CDK2 and CDC7. Here we report a novel mechanism in which p53 induces G1 checkpoint and cell cycle arrest by downregulating CDC7 kinase in response to genotoxic stress. We demonstrate that p53 controls CDC7 stability post-transcriptionally via miR-192/215 and post-translationally via Fbxw7β E3 ubiquitin ligase. The p53-dependent pathway of CDC7 downregulation is interlinked with the p53-p21-CDK2 pathway, as p21-mediated inhibition of CDK2-dependent phosphorylation of CDC7 on Thr376 is required for GSK3ß-phosphorylation and Fbxw7ß-dependent degradation of CDC7. Notably, sustained oncogenic high levels of active CDC7 exert a negative feedback onto p53, leading to unrestrained S-phase progression and accumulation of DNA damage. Thus, p53-dependent control of CDC7 levels is essential for blocking G1/S cell-cycle transition upon genotoxic stress, thereby safeguarding the genome from instability and thus representing a novel general stress response.
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Affiliation(s)
- Slavica Tudzarova
- a Wolfson Institute for Biomedical Research, Division of Medicine, University College London , London , UK.,b Division of Endocrinology, David Geffen School of Medicine, University of California Los Angeles , Los Angeles , CA , USA
| | - Paul Mulholland
- c Department of Pathology , UCL Cancer Institute, University College London , London , UK
| | - Ayona Dey
- a Wolfson Institute for Biomedical Research, Division of Medicine, University College London , London , UK
| | - Kai Stoeber
- c Department of Pathology , UCL Cancer Institute, University College London , London , UK
| | - Andrei L Okorokov
- a Wolfson Institute for Biomedical Research, Division of Medicine, University College London , London , UK
| | - Gareth H Williams
- c Department of Pathology , UCL Cancer Institute, University College London , London , UK.,d Oncologica Ltd, The Science Village, Chesterford Research Park , Cambridge , UK
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18
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He Y, Yan D, Zheng D, Hu Z, Li H, Li J. Cell Division Cycle 6 Promotes Mitotic Slippage and Contributes to Drug Resistance in Paclitaxel-Treated Cancer Cells. PLoS One 2016; 11:e0162633. [PMID: 27611665 PMCID: PMC5017606 DOI: 10.1371/journal.pone.0162633] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/25/2016] [Indexed: 12/18/2022] Open
Abstract
Paclitaxel (PTX) is an antimitotic drug that possesses potent anticancer activity, but its therapeutic potential in the clinic has been hindered by drug resistance. Here, we report a mechanism by which cancer cells can exit from the PTX-induced mitotic arrest, i.e. mitotic slippage, and avoid subsequent death resulting in drug resistance. In cells experiencing mitotic slippage, Cdc6 protein level was significantly upregulated, Cdk1 activity was inhibited, and Cohesin/Rad21 was cleaved as a result. Cdc6 depletion by RNAi or Norcantharidin inhibited PTX-induced Cdc6 up-regulation, maintained Cdk1 activity, and repressed Cohesin/Rad21 cleavage. In all, this resulted in reduced mitotic slippage and reversal of PTX resistance. Moreover, in synchronized cells, the role of Cdc6 in mitotic exit under PTX pressure was also confirmed. This study indicates that Cdc6 may promote mitotic slippage by inactivation of Cdk1. Targeting of Cdc6 may serve as a promising strategy for enhancing the anticancer activity of PTX.
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Affiliation(s)
- Yue He
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Daoyu Yan
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Dianpeng Zheng
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Zhiming Hu
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Hongwei Li
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
- * E-mail: (JL); (HL)
| | - Jinlong Li
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
- * E-mail: (JL); (HL)
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19
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Kalfalah FM, Berg E, Christensen MO, Linka RM, Dirks WG, Boege F, Mielke C. Spatio-temporal regulation of the human licensing factor Cdc6 in replication and mitosis. Cell Cycle 2016; 14:1704-15. [PMID: 25875233 PMCID: PMC4614858 DOI: 10.1080/15384101.2014.1000182] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
To maintain genome stability, the thousands of replication origins of mammalian genomes must only initiate replication once per cell cycle. This is achieved by a strict temporal separation of ongoing replication in S phase, and the formation of pre-replicative complexes in the preceding G1 phase, which "licenses" each origin competent for replication. The contribution of the loading factor Cdc6 to the timing of the licensing process remained however elusive due to seemingly contradictory findings concerning stabilization, degradation and nuclear export of Cdc6. Using fluorescently tagged Cdc6 (Cdc6-YFP) expressed in living cycling cells, we demonstrate here that Cdc6-YFP is stable and chromatin-associated during mitosis and G1 phase. It undergoes rapid proteasomal degradation during S phase initiation followed by active export to the cytosol during S and G2 phases. Biochemical fractionation abolishes this nuclear exclusion, causing aberrant chromatin association of Cdc6-YFP and, likely, endogenous Cdc6, too. In addition, we demonstrate association of Cdc6 with centrosomes in late G2 and during mitosis. These results show that multiple Cdc6-regulatory mechanisms coexist but are tightly controlled in a cell cycle-specific manner.
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Affiliation(s)
- Faiza M Kalfalah
- a Institute of Clinical Chemistry and Laboratory Diagnostics; University Düsseldorf; Medical Faculty , Düsseldorf , Germany
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20
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Daldello EM, Le T, Poulhe R, Jessus C, Haccard O, Dupré A. Fine-tuning of Cdc6 accumulation by Cdk1 and MAP kinase is essential for completion of oocyte meiotic divisions. J Cell Sci 2015; 128:2482-96. [DOI: 10.1242/jcs.166553] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 05/19/2015] [Indexed: 01/28/2023] Open
Abstract
Vertebrate oocytes proceed through the 1st and the 2nd meiotic division without intervening S-phase to become haploid. Although DNA replication does not take place, unfertilized oocytes acquire the competence to replicate DNA one hour after the 1st meiotic division, by accumulating an essential factor of the replicative machinery, Cdc6. Here, we discovered that the turnover of Cdc6 is precisely regulated in oocytes to avoid inhibition of Cdk1. At meiosis resumption, Cdc6 starts to be expressed but cannot accumulate due to a degradation mechanism activated through Cdk1. During transition from 1st to 2nd meiotic division, Cdc6 is under antagonistic regulation of Cyclin B, whose interaction with Cdc6 stabilizes the protein, and Mos/MAPK that negatively controls its accumulation. Since overexpressing Cdc6 inhibits Cdk1 reactivation and drives oocytes into a replicative interphasic state, the fine-tuning of Cdc6 accumulation is essential to ensure two meiotic waves of Cdk1 activation and to avoid unscheduled DNA replication during meiotic maturation.
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Affiliation(s)
- Enrico M. Daldello
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
| | - Tran Le
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
| | - Robert Poulhe
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
| | - Catherine Jessus
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
| | - Olivier Haccard
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
| | - Aude Dupré
- UPMC Univ Paris 06, UMR7622-Biologie du Développement, Paris, France
- CNRS, UMR7622-Biologie du Développement, Paris, France
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21
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El Dika M, Laskowska-Kaszub K, Koryto M, Dudka D, Prigent C, Tassan JP, Kloc M, Polanski Z, Borsuk E, Kubiak JZ. CDC6 controls dynamics of the first embryonic M-phase entry and progression via CDK1 inhibition. Dev Biol 2014; 396:67-80. [DOI: 10.1016/j.ydbio.2014.09.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 09/18/2014] [Accepted: 09/19/2014] [Indexed: 11/29/2022]
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22
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Alver RC, Chadha GS, Blow JJ. The contribution of dormant origins to genome stability: from cell biology to human genetics. DNA Repair (Amst) 2014; 19:182-9. [PMID: 24767947 PMCID: PMC4065331 DOI: 10.1016/j.dnarep.2014.03.012] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The ability of a eukaryotic cell to precisely and accurately replicate its DNA is crucial to maintain genome stability. Here we describe our current understanding of the process by which origins are licensed for DNA replication and review recent work suggesting that fork stalling has exerted a strong selective pressure on the positioning of licensed origins. In light of this, we discuss the complex and disparate phenotypes observed in mouse models and humans patients that arise due to defects in replication licensing proteins.
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Affiliation(s)
- Robert C Alver
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Gaganmeet Singh Chadha
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - J Julian Blow
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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23
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Interplay between the cell cycle and double-strand break response in mammalian cells. Methods Mol Biol 2014; 1170:41-59. [PMID: 24906308 DOI: 10.1007/978-1-4939-0888-2_3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The cell cycle is intimately associated with the ability of cells to sense and respond to and repair DNA damage. Understanding how cell cycle progression, particularly DNA replication and cell division, are regulated and how DNA damage can affect these processes has been the subject of intense research. Recent evidence suggests that the repair of DNA damage is regulated by the cell cycle, and that cell cycle factors are closely associated with repair factors and participate in cellular decisions regarding how to respond to and repair damage. Precise regulation of cell cycle progression in the presence of DNA damage is essential to maintain genomic stability and avoid the accumulation of chromosomal aberrations that can promote tumor formation. In this review, we discuss the current understanding of how mammalian cells induce cell cycle checkpoints in response to DNA double-strand breaks. In addition, we discuss how cell cycle factors modulate DNA repair pathways to facilitate proper repair of DNA lesions.
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24
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Abstract
DNA replication is tightly controlled in eukaryotic cells to ensure that an exact copy of the genetic material is inherited by both daughter cells. Oscillating waves of cyclin-dependent kinase (CDK) and anaphase-promoting complex/cyclosome (APC/C) activities provide a binary switch that permits the replication of each chromosome exactly once per cell cycle. Work from several organisms has revealed a conserved strategy whereby inactive replication complexes are assembled onto DNA during periods of low CDK and high APC activity but are competent to execute genome duplication only when these activities are reversed. Periods of high CDK and low APC/C serve an essential function by blocking reassembly of replication complexes, thereby preventing rereplication. Higher eukaryotes have evolved additional CDK-independent mechanisms for preventing rereplication.
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Affiliation(s)
- Khalid Siddiqui
- Cancer Research UK, London Research Institute, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, United Kingdom
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25
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CHEN SANSAN, WAN PEI, DING WEN, LI FEI, HE CHENGWU, CHEN PENGLIANG, LI HONGWEI, HU ZHIMING, TAN WANLONG, LI JINLONG. Norcantharidin inhibits DNA replication and induces mitotic catastrophe by degrading initiation protein Cdc6. Int J Mol Med 2013; 32:43-50. [DOI: 10.3892/ijmm.2013.1359] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 04/08/2013] [Indexed: 11/06/2022] Open
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Yim H, Park JW, Woo SU, Kim ST, Liu L, Lee CH, Lee SK. Phosphorylation of Cdc6 at serine 74, but not at serine 106, drives translocation of Cdc6 to the cytoplasm. J Cell Physiol 2013; 228:1221-8. [PMID: 23129444 DOI: 10.1002/jcp.24275] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 10/19/2012] [Indexed: 11/08/2022]
Abstract
Phosphorylation-dependent cytoplasmic translocation of human Cdc6 during S phase is sufficient to control its activity after origin firing. Export from the nucleus also serves as a mechanism for preventing re-replication in mammalian cells. Phosphorylation of the CDK consensus serine residues 54, 74, and 106 has been suggested to be involved in the cytoplasmic translocation of Cdc6. To determine the relative importance of the three phosphorylation sites, we have generated Cdc6 variants by substituting one or more of the three serine residues with alanine or aspartic acid and have assessed their cytoplasmic translocation behavior. Phosphorylation of serine 74 mainly contributes to the cytoplasmic translocation of Cdc6, while serine 54 phosphorylation provides a minor contribution. In contrast, phosphorylation at serine 106 does not affect the nuclear export of Cdc6. Comparative results were found in cells coexpressing the phosphorylation defective mutants of Cdc6 and cyclin A as well as in non-transfected cells synchronized by their release from a double thymidine block. We conclude that Cdk-mediated phosphorylation of Cdc6 at serine 74 is required for the cytoplasmic translocalization of Cdc6 during the cell cycle. Phosphorylation of Cdc6 at serine 54 plays a minor role and phosphorylation of serine 106 plays no role in the cytoplasmic localization of Cdc6. The phosphorylation of S74 in Cdc6 could be important for binding to the nuclear export protein for translocalization.
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Affiliation(s)
- Hyungshin Yim
- Division of Pharmaceutical Biosciences, Research Institute for Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Republic of Korea.
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Varma D, Chandrasekaran S, Sundin LJR, Reidy KT, Wan X, Chasse DAD, Nevis KR, DeLuca JG, Salmon ED, Cook JG. Recruitment of the human Cdt1 replication licensing protein by the loop domain of Hec1 is required for stable kinetochore-microtubule attachment. Nat Cell Biol 2012; 14:593-603. [PMID: 22581055 PMCID: PMC3366049 DOI: 10.1038/ncb2489] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 03/26/2012] [Indexed: 11/09/2022]
Abstract
Cdt1, a protein critical for replication origin licensing in G1 phase, is degraded during S phase but re-accumulates in G2 phase. We now demonstrate that human Cdt1 has a separable essential mitotic function. Cdt1 localizes to kinetochores during mitosis through interaction with the Hec1 component of the Ndc80 complex. G2-specific depletion of Cdt1 arrests cells in late prometaphase owing to abnormally unstable kinetochore-microtubule (kMT) attachments and Mad1-dependent spindle-assembly-checkpoint activity. Cdt1 binds a unique loop extending from the rod domain of Hec1 that we show is also required for kMT attachment. Mutation of the loop domain prevents Cdt1 kinetochore localization and arrests cells in prometaphase. Super-resolution fluorescence microscopy indicates that Cdt1 binding to the Hec1 loop domain promotes a microtubule-dependent conformational change in the Ndc80 complex in vivo. These results support the conclusion that Cdt1 binding to Hec1 is essential for an extended Ndc80 configuration and stable kMT attachment.
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Affiliation(s)
- Dileep Varma
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Sacco E, Hasan MM, Alberghina L, Vanoni M. Comparative analysis of the molecular mechanisms controlling the initiation of chromosomal DNA replication in yeast and in mammalian cells. Biotechnol Adv 2012; 30:73-98. [DOI: 10.1016/j.biotechadv.2011.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 09/14/2011] [Indexed: 11/26/2022]
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Xiong Y, Zhang L, Holloway AK, Wu X, Su L, Kebebew E. MiR-886-3p regulates cell proliferation and migration, and is dysregulated in familial non-medullary thyroid cancer. PLoS One 2011; 6:e24717. [PMID: 21998631 PMCID: PMC3187745 DOI: 10.1371/journal.pone.0024717] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 08/17/2011] [Indexed: 01/09/2023] Open
Abstract
Background The molecular basis and characteristics of familial non-medullary thyroid cancer are poorly understood. In this study, we performed microRNA (miRNA) profiling of familial and sporadic papillary thyroid cancer tumor samples. Methodology/Principal Findings Genome wide miRNA profiling of sporadic and familial papillary thyroid cancer was performed. Differentially expressed miRNAs were validated by quantitative RT-PCR. Ectopic expression of miR-886-3p in thyroid cancer lines was performed to identify pathways targeted by the miRNA, as well as, to determine its effect on tumor cell biology. We found four differentially expressed miRNAs between familial and sporadic papillary thyroid cancer tumor samples. MiR-886-3p and miR-20a were validated to be differentially expressed by 3- and 4-fold, respectively. Pathway analysis of genome-wide expression data on cells overexpressing miR-886-3p and target prediction analysis showed genes involved in DNA replication and focal adhesion pathways were regulated by miR-886-3p. Overexpression of miR-886-3p in thyroid cancer cell lines significantly inhibited cellular proliferation, the number and size of spheroids and cellular migration. Additionally, overexpression of miR-886-3p increased the number of cells in S phase. Conclusions/Significance Our findings for the first time suggest that miR-886-3p plays an important role in thyroid cancer tumor cell biology and regulates genes involved in DNA replication and focal adhesion. Thus, miR-886-3p may play a role in the initiation and or progression of papillary thyroid cancer.
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Affiliation(s)
- Yin Xiong
- Endocrine Oncology Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Lisa Zhang
- Endocrine Oncology Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Alisha K. Holloway
- Gladstone Institutes, University of California San Francisco, San Francisco, California, United States of America
| | - Xiaolin Wu
- Laboratory of Molecular Technology, Science Applications International Coorporation-Frederick, Inc., National Cancer Institute, Frederick, Maryland, United States of America
| | - Ling Su
- Laboratory of Molecular Technology, Science Applications International Coorporation-Frederick, Inc., National Cancer Institute, Frederick, Maryland, United States of America
| | - Electron Kebebew
- Endocrine Oncology Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
- * E-mail:
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Abstract
Preservation of genome integrity via the DNA-damage response is critical to prevent disease. ATR (ataxia telangiectasia mutated- and Rad3-related) is essential for life and functions as a master regulator of the DNA-damage response, especially during DNA replication. ATR controls and co-ordinates DNA replication origin firing, replication fork stability, cell cycle checkpoints and DNA repair. Since its identification 15 years ago, a model of ATR activation and signalling has emerged that involves localization to sites of DNA damage and activation through protein-protein interactions. Recent research has added an increasingly detailed understanding of the canonical ATR pathway, and an appreciation that the canonical model does not fully capture the complexity of ATR regulation. In the present article, we review the ATR signalling process, focusing on mechanistic findings garnered from the identification of new ATR-interacting proteins and substrates. We discuss how to incorporate these new insights into a model of ATR regulation and point out the significant gaps in our understanding of this essential genome-maintenance pathway.
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31
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Yim H, Erikson RL. Regulation of the final stage of mitosis by components of the pre-replicative complex and a polo kinase. Cell Cycle 2011; 10:1374-7. [PMID: 21519187 PMCID: PMC3117042 DOI: 10.4161/cc.10.9.15489] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 03/15/2011] [Indexed: 11/19/2022] Open
Abstract
The accurate division of duplicated DNA is essential for maintenance of genomic stability in proliferating eukaryotic cells. Errors in DNA replication and chromosomal segregation may lead to cell death or genomic mutations that lead to oncogenic properties. Thus, tight regulation of DNA replication and mitosis is essential for maintaining genomic integrity. Cell division cycle 6 (Cdc6) is an essential factor for initiating DNA replication. Recent work shows that phosphorylation of Cdc6 by polo-like kinase 1 (Plk1), one of the essential mitotic kinases, regulates mitotic exit mediated by Cdk1 and separase. Here we discuss how pre-replicative complex factors are connected with Plk1 and affect mitotic exit.
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Affiliation(s)
- Hyungshin Yim
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
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Yoshida K, Sugimoto N, Iwahori S, Yugawa T, Narisawa-Saito M, Kiyono T, Fujita M. CDC6 interaction with ATR regulates activation of a replication checkpoint in higher eukaryotic cells. J Cell Sci 2010; 123:225-35. [PMID: 20048340 DOI: 10.1242/jcs.058693] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
CDC6, a replication licensing protein, is partially exported to the cytoplasm in human cells through phosphorylation by Cdk during S phase, but a significant proportion remains in the nucleus. We report here that human CDC6 physically interacts with ATR, a crucial checkpoint kinase, in a manner that is stimulated by phosphorylation by Cdk. CDC6 silencing by siRNAs affected ATR-dependent inhibition of mitotic entry elicited by modest replication stress. Whereas a Cdk-phosphorylation-mimicking CDC6 mutant could rescue the checkpoint defect by CDC6 silencing, a phosphorylation-deficient mutant could not. Furthermore, we found that the CDC6-ATR interaction is conserved in Xenopus. We show that the presence of Xenopus CDC6 during S phase is essential for Xenopus ATR to bind to chromatin in response to replication inhibition. In addition, when human CDC6 amino acid fragment 180-220, which can bind to both human and Xenopus ATR, was added to Xenopus egg extracts after assembly of the pre-replication complex, Xenopus Chk1 phosphorylation was significantly reduced without lowering replication, probably through a sequestration of CDC6-mediated ATR-chromatin interaction. Thus, CDC6 might regulate replication-checkpoint activation through the interaction with ATR in higher eukaryotic cells.
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Affiliation(s)
- Kazumasa Yoshida
- Virology Division, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuohku, Tokyo 104-0045, Japan
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Chung JH, Bunz F. Cdk2 is required for p53-independent G2/M checkpoint control. PLoS Genet 2010; 6:e1000863. [PMID: 20195506 PMCID: PMC2829054 DOI: 10.1371/journal.pgen.1000863] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 01/28/2010] [Indexed: 01/03/2023] Open
Abstract
The activation of phase-specific cyclin-dependent kinases (Cdks) is associated with ordered cell cycle transitions. Among the mammalian Cdks, only Cdk1 is essential for somatic cell proliferation. Cdk1 can apparently substitute for Cdk2, Cdk4, and Cdk6, which are individually dispensable in mice. It is unclear if all functions of non-essential Cdks are fully redundant with Cdk1. Using a genetic approach, we show that Cdk2, the S-phase Cdk, uniquely controls the G2/M checkpoint that prevents cells with damaged DNA from initiating mitosis. CDK2-nullizygous human cells exposed to ionizing radiation failed to exclude Cdk1 from the nucleus and exhibited a marked defect in G2/M arrest that was unmasked by the disruption of P53. The DNA replication licensing protein Cdc6, which is normally stabilized by Cdk2, was physically associated with the checkpoint regulator ATR and was required for efficient ATR-Chk1-Cdc25A signaling. These findings demonstrate that Cdk2 maintains a balance of S-phase regulatory proteins and thereby coordinates subsequent p53-independent G2/M checkpoint activation. Metazoan cells contain multiple Cdks that regulate cell cycle progression. Recent studies have shown that mouse cells can grow normally with just Cdk1. The roles of the non-essential Cdks remain a fundamental question. In this study, we describe the generation and detailed characterization of CDK2-knockout human somatic cells. Our study demonstrates that Cdk2 is required for robust DNA damage checkpoint signaling. Loss of Cdk2 caused a marked deficiency in the G2/M arrest—a basic response to DNA damage—in cells that were also nullizygous for P53. We propose that the multiple Cdks present in metazoan cells provide a mechanism by which the cell cycle can be efficiently halted after DNA damage. Significantly, this study reveals a heretofore unrecognized dependence for Cdk2 in p53-deficient cancer cells.
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Affiliation(s)
- Jon H. Chung
- Department of Radiation Oncology and Molecular Radiation Sciences and The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Fred Bunz
- Department of Radiation Oncology and Molecular Radiation Sciences and The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Boruc J, Mylle E, Duda M, De Clercq R, Rombauts S, Geelen D, Hilson P, Inzé D, Van Damme D, Russinova E. Systematic localization of the Arabidopsis core cell cycle proteins reveals novel cell division complexes. PLANT PHYSIOLOGY 2010; 152:553-65. [PMID: 20018602 PMCID: PMC2815867 DOI: 10.1104/pp.109.148643] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 12/08/2009] [Indexed: 05/18/2023]
Abstract
Cell division depends on the correct localization of the cyclin-dependent kinases that are regulated by phosphorylation, cyclin proteolysis, and protein-protein interactions. Although immunological assays can define cell cycle protein abundance and localization, they are not suitable for detecting the dynamic rearrangements of molecular components during cell division. Here, we applied an in vivo approach to trace the subcellular localization of 60 Arabidopsis (Arabidopsis thaliana) core cell cycle proteins fused to green fluorescent proteins during cell division in tobacco (Nicotiana tabacum) and Arabidopsis. Several cell cycle proteins showed a dynamic association with mitotic structures, such as condensed chromosomes and the preprophase band in both species, suggesting a strong conservation of targeting mechanisms. Furthermore, colocalized proteins were shown to bind in vivo, strengthening their localization-function connection. Thus, we identified unknown spatiotemporal territories where functional cell cycle protein interactions are most likely to occur.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Eugenia Russinova
- Department of Plant Systems Biology, Flanders Institute for Biotechnology, B–9052 Ghent, Belgium (J.B., E.M., M.D., R.D.C., S.R., P.H., D.I., D.V.D., E.R.); Department of Plant Biotechnology and Genetics, Ghent University, B–9052 Ghent, Belgium (J.B., E.M., M.D., R.D.C., S.R., P.H., D.I., D.V.D., E.R.); and Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, B–9000 Ghent, Belgium (D.G.)
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Lu X, Liu J, Legerski RJ. Cyclin E is stabilized in response to replication fork barriers leading to prolonged S phase arrest. J Biol Chem 2010; 284:35325-37. [PMID: 19812034 DOI: 10.1074/jbc.m109.035949] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclin E is a regulator of cyclin-dependent protein kinases (Cdks) and is involved in mediating the cell cycle transition from G(1) to S phase. Here, we describe a novel function for cyclin E in the long term maintenance of checkpoint arrest in response to replication barriers. Exposure of cells to mitomycin C or UV irradiation, but not ionizing radiation, induces stabilization of cyclin E. Stabilization of cyclin E reduces the activity of Cdk2-cyclin A, resulting in a slowing of S phase progression and arrest. In addition, cyclin E is shown to be required for stabilization of Cdc6, which is required for activation of Chk1 and the replication checkpoint pathway. Furthermore, the stabilization of cyclin E in response to replication fork barriers depends on ATR, but not Nbs1 or Chk1. These results indicate that in addition to its well studied role in promoting cell cycle progression, cyclin E also has a role in regulating cell cycle arrest in response to DNA damage.
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Affiliation(s)
- Xiaoyan Lu
- Department of Genetics, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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Zhang K, Sha J, Harter ML. Activation of Cdc6 by MyoD is associated with the expansion of quiescent myogenic satellite cells. ACTA ACUST UNITED AC 2010; 188:39-48. [PMID: 20048262 PMCID: PMC2812847 DOI: 10.1083/jcb.200904144] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cdc6, which alters chromatin ultrastructure to allow DNA replication in muscle stem cells transitioning out of quiescence, is identified as a target of the MyoD transcription factor. MyoD is a transcriptional factor that is required for the differentiation of muscle stem cells (satellite cells). In this study, we describe a previously unknown function for MyoD in regulating a gene (Cdc6) that is vital to endowing chromatin with the capability of replicating DNA. In C2C12 and primary mouse myoblasts, we show that MyoD can occupy an E-box within the promoter of Cdc6 and that this association, along with E2F3a, is required for its activity. MyoD and Cdc6 are both expressed after quiescent C2C12 myoblasts or satellite cells in association with myofibers are stimulated for growth, but MyoD appears at least 2–3 h earlier than Cdc6. Finally, knockdown of MyoD impairs the ability of C2C12 cells to express Cdc6 after leaving quiescence, and as a result, they cannot fully progress into S phase. Our results define a mechanism by which MyoD helps myogenic satellite cells to enter into the first round of DNA replication after transitioning out of quiescence.
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Affiliation(s)
- Keman Zhang
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA
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37
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Lau E, Chiang GG, Abraham RT, Jiang W. Divergent S phase checkpoint activation arising from prereplicative complex deficiency controls cell survival. Mol Biol Cell 2009; 20:3953-64. [PMID: 19587119 DOI: 10.1091/mbc.e09-01-0022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The DNA replication machinery plays additional roles in S phase checkpoint control, although the identities of the replication proteins involved in checkpoint activation remain elusive. Here, we report that depletion of the prereplicative complex (pre-RC) protein Cdc6 causes human nontransformed diploid cells to arrest nonlethally in G1-G1/S and S phase, whereas multiple cancer cell lines undergo G1-G1/S arrest and cell death. These divergent phenotypes are dependent on the activation, or lack thereof, of an ataxia telangiectasia and Rad3-related (ATR)-dependent S phase checkpoint that inhibits replication fork progression. Although pre-RC deficiency induces chromatin structural alterations in both nontransformed and cancer cells that normally lead to ATR checkpoint activation, the sensor mechanisms in cancer cells seem to be compromised such that higher levels of DNA replication stress/damage are required to trigger checkpoint response. Our results suggest that therapy-induced disruption of pre-RC function might exert selective cytotoxic effects on tumor cells in human patients.
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Affiliation(s)
- Eric Lau
- The Burnham Institute for Medical Research, La Jolla, CA 92037, USA
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38
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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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Paolinelli R, Mendoza-Maldonado R, Cereseto A, Giacca M. Acetylation by GCN5 regulates CDC6 phosphorylation in the S phase of the cell cycle. Nat Struct Mol Biol 2009; 16:412-20. [PMID: 19343071 DOI: 10.1038/nsmb.1583] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 03/04/2009] [Indexed: 01/21/2023]
Abstract
In eukaryotic cells, the cell-division cycle (CDC)-6 protein is essential to promote the assembly of pre-replicative complexes in the early G1 phase of the cell cycle, a process requiring tight regulation to ensure that proper origin licensing occurs once per cell cycle. Here we show that, in late G1 and early S phase, CDC6 is found in a complex also containing Cyclin A, cyclin-dependent kinase (CDK)-2 and the acetyltransferase general control nonderepressible 5 (GCN5). GCN5 specifically acetylates CDC6 at three lysine residues flanking its cyclin-docking motif, and this modification is crucial for the subsequent phosphorylation of the protein by Cyclin A-CDKs at a specific residue close to the acetylation site. GCN5-mediated acetylation and site-specific phosphorylation of CDC6 are both necessary for the relocalization of the protein to the cell cytoplasm in the S phase, as well as to regulate its stability. This two-step, intramolecular regulatory program by sequential modification of CDC6 seems to be essential for proper S-phase progression.
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Affiliation(s)
- Roberta Paolinelli
- Molecular Biology Laboratory, Scuola Normale Superiore, AREA della Ricerca del CNR, Pisa, Italy
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Ueda S, Kondoh N, Tsuda H, Yamamoto S, Asakawa H, Fukatsu K, Kobayashi T, Yamamoto J, Tamura K, Ishida J, Abe Y, Yamamoto M, Mochizuki H. Expression of centromere protein F (CENP-F) associated with higher FDG uptake on PET/CT, detected by cDNA microarray, predicts high-risk patients with primary breast cancer. BMC Cancer 2008; 8:384. [PMID: 19102762 PMCID: PMC2631591 DOI: 10.1186/1471-2407-8-384] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 12/22/2008] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Higher standardized uptake value (SUV) detected by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) correlates with proliferation of primary breast cancer. The purpose of this study is to identify specific molecules upregulated in primary breast cancers with a high SUV and to examine their clinical significance. METHODS We compared mRNA expression profiles between 14 tumors with low SUVs and 24 tumors with high SUVs by cDNA microarray. We identified centromere protein F (CENP-F) and CDC6 were upregulated in tumors with high SUVs. RT-PCR and immunohistochemical analyses were performed to validate these data. Clinical implication of CENP-F and CDC6 was examined for 253 archival breast cancers by the tissue microarray. RESULTS The relative ratios of CENP-F and CDC6 expression levels to beta-actin were confirmed to be significantly higher in high SUV tumors than in low SUV tumors (p = 0.027 and 0.025, respectively) by RT-PCR. In immunohistochemical analysis of 47 node-negative tumors, the CENP-F expression was significantly higher in the high SUV tumors (74%) than the low SUV tumors (45%) (p = 0.04), but membranous and cytoplasmic CDC6 expressions did not significantly differ between both groups (p = 0.9 each). By the tissue microarray, CENP-F (HR = 2.94) as well as tumor size (HR = 4.49), nodal positivity (HR = 4.1), and Ki67 (HR = 2.05) showed independent impact on the patients' prognosis. CONCLUSION High CENP-F expression, correlated with high SUV, was the prognostic indicators of primary breast cancer. Tumoral SUV levels may serve as a pretherapeutic indicator of aggressiveness of breast cancer.
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Affiliation(s)
- Shigeto Ueda
- Department of Basic Pathology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
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Xiong XD, Qiu FE, Fang JH, Shen Y, Liang C, Jiang W, Zhuang SM. Association analysis between the Cdc6 G1321A polymorphism and the risk for non-Hodgkin lymphoma and hepatocellular carcinoma. Mutat Res 2008; 662:10-5. [PMID: 19101572 DOI: 10.1016/j.mrfmmm.2008.11.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2008] [Revised: 10/28/2008] [Accepted: 11/21/2008] [Indexed: 12/20/2022]
Abstract
Cdc6 play crucial roles in DNA replication and carcinogenesis. The biological significance of the Cdc6 G1321A polymorphism (V441I, rs13706) is still not elucidated. Here we examined the influence of this polymorphism on the function of Cdc6 and the individual's susceptibility to non-Hodgkin lymphoma (NHL) and hepatocellular carcinoma (HCC). Unconditional logistic regression analysis revealed that the risk for NHL was significantly reduced in both AG heterozygotes [odds ratio (OR)=0.67, P=0.019] and AA homozygotes (OR=0.54, P=0.026), compared with GG homozygotes. Further stratification by subtypes of NHL showed that the AG as well as combined AA/AG genotypes were associated with decreased risk for B-cell-NHL (OR=0.62, P=0.011 and OR=0.61, P=0.006, respectively), especially for diffuse large B-cell lymphoma (DLBCL, OR=0.63, P=0.025 and OR=0.62, P=0.012, respectively). In addition, male individuals with the AA genotype displayed borderline significantly reduced risk for HCC (OR=0.48, P=0.054). Interestingly, the G1321A polymorphism did not affect caspase-mediated cleavage of Cdc6 during etoposide-induced apoptosis, but it was predicted to alter the secondary structure of Cdc6 mRNA. Our data provide the first evidence that the Cdc6 G1321A polymorphism is associated with decreased risk of cancer. Further studies are necessary to confirm the general validity of our findings.
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Affiliation(s)
- Xing-Dong Xiong
- Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
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Abstract
Correct regulation of the replication licensing system ensures that chromosomal DNA is precisely duplicated in each cell division cycle. Licensing proteins are inappropriately expressed at an early stage of tumorigenesis in a wide variety of cancers. Here we discuss evidence that misregulation of replication licensing is a consequence of oncogene-induced cell proliferation. This misregulation can cause either under- or over-replication of chromosomal DNA, and could explain the genetic instability commonly seen in cancer cells.
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Affiliation(s)
- J Julian Blow
- Wellcome Trust Centre for Gene Regulation & Expression, University of Dundee, DD1 5EH, UK.
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Crevel G, Bennett D, Cotterill S. The human TPR protein TTC4 is a putative Hsp90 co-chaperone which interacts with CDC6 and shows alterations in transformed cells. PLoS One 2008; 3:e0001737. [PMID: 18320024 PMCID: PMC2253824 DOI: 10.1371/journal.pone.0001737] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 01/30/2008] [Indexed: 01/28/2023] Open
Abstract
Background The human TTC4 protein is a TPR (tetratricopeptide repeat) motif-containing protein. The gene was originally identified as being localized in a genomic region linked to breast cancer and subsequent studies on melanoma cell lines revealed point mutations in the TTC4 protein that may be associated with the progression of malignant melanoma. Methodology/Principle Findings Here we show that TTC4 is a nucleoplasmic protein which interacts with HSP90 and HSP70, and also with the replication protein CDC6. It has significant structural and functional similarities with a previously characterised Drosophila protein Dpit47. We show that TTC4 protein levels are raised in malignant melanoma cell lines compared to melanocytes. We also see increased TTC4 expression in a variety of tumour lines derived from other tissues. In addition we show that TTC4 proteins bearing some of the mutations previously identified from patient samples lose their interaction with the CDC6 protein. Conclusions/Significance Based on these results and our previous work with the Drosophila Dpit47 protein we suggest that TTC4 is an HSP90 co-chaperone protein which forms a link between HSP90 chaperone activity and DNA replication. We further suggest that the loss of the interaction with CDC6 or with additional client proteins could provide one route through which TTC4 could influence malignant development of cells.
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Affiliation(s)
- Gilles Crevel
- Department of Basic Medical Sciences, St Georges Hospital Medical School, London, United Kingdom
| | - Dorothy Bennett
- Department of Basic Medical Sciences, St Georges Hospital Medical School, London, United Kingdom
| | - Sue Cotterill
- Department of Basic Medical Sciences, St Georges Hospital Medical School, London, United Kingdom
- *E-mail:
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Feng L, Barnhart JR, Seeger RC, Wu L, Keshelava N, Huang SH, Jong A. Cdc6 knockdown inhibits human neuroblastoma cell proliferation. Mol Cell Biochem 2008; 311:189-97. [DOI: 10.1007/s11010-008-9709-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 01/10/2008] [Indexed: 01/11/2023]
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Borlado LR, Méndez J. CDC6: from DNA replication to cell cycle checkpoints and oncogenesis. Carcinogenesis 2007; 29:237-43. [PMID: 18048387 DOI: 10.1093/carcin/bgm268] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cell division cycle 6 (CDC6) is an essential regulator of DNA replication in eukaryotic cells. Its best-characterized function is the assembly of prereplicative complexes at origins of replication during the G(1) phase of the cell division cycle. However, CDC6 also plays important roles in the activation and maintenance of the checkpoint mechanisms that coordinate S phase and mitosis, and recent studies have unveiled its proto-oncogenic activity. CDC6 overexpression interferes with the expression of INK4/ARF tumor suppressor genes through a mechanism involving the epigenetic modification of chromatin at the INK4/ARF locus. In addition, CDC6 overexpression in primary cells may promote DNA hyperreplication and induce a senescence response similar to that caused by oncogene activation. These findings indicate that deregulation of CDC6 expression in human cells poses a serious risk of carcinogenesis.
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Affiliation(s)
- Luis R Borlado
- DNA replication Group, Molecular Oncology Programme, Spanish National Cancer Research Centre, Melchor Fernández Almagro 3, E-28029 Madrid, Spain
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Lau E, Tsuji T, Guo L, Lu SH, Jiang W. The role of pre‐replicative complex (pre‐RC) components in oncogenesis. FASEB J 2007; 21:3786-94. [PMID: 17690155 DOI: 10.1096/fj.07-8900rev] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Normal DNA replication is stringently regulated to ensure a timely occurrence no more than once per cell cycle. Abrogation of the exquisite control mechanisms that maintain this process results in detrimental gains and losses of genomic DNA commonly seen in cancer and developmental defects. Replication initiation proteins, known as prereplicative complex (pre-RC) proteins, serve as a primary level of regulation, controlling when DNA replication can begin. Unsurprisingly, several pre-RC proteins are overexpressed in cancer and serve as good tumor markers. However, their direct correlation with increasing tumor grade and poor prognosis has posed a long-standing question: Are pre-RC proteins oncogenic? Recently, a growing body of data indicates that deregulation of individual pre-RC proteins, either by overexpression or functional deficiency in several organismal models, results in significant and consistently perturbed cell cycle regulation, genomic instability, and, potentially, tumorigenesis. In this review, we examine this broad range of evidence suggesting that pre-RC proteins play roles during oncogenesis that are more than simply indicative of proliferation, supporting the notion that pre-RC proteins may potentially have significant diagnostic and therapeutic value.
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Affiliation(s)
- Eric Lau
- The Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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47
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Cdc18 enforces long-term maintenance of the S phase checkpoint by anchoring the Rad3-Rad26 complex to chromatin. Mol Cell 2007; 26:553-63. [PMID: 17531813 DOI: 10.1016/j.molcel.2007.04.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Revised: 02/26/2007] [Accepted: 04/20/2007] [Indexed: 01/11/2023]
Abstract
DNA replication is initiated by recruitment of Cdc18 to origins. During S phase, CDK-dependent destruction of Cdc18 occurs. We show that when DNA replication stalls, Cdc18 persists in a chromatin-bound complex including the checkpoint kinases Rad3 and Rad26. Rad26 directly binds Cdc18 and is required for Rad3 recruitment to chromatin. Depletion of Cdc18 when DNA replication is stalled leads to release of Rad3 and Rad26 from chromatin and entry into an aberrant mitosis even though replication intermediates can still be detected. These findings indicate that Cdc18 plays a pivotal role in checkpoint maintenance by anchoring the Rad3-Rad26 complex to chromatin. Cdc18 persistence during DNA-replication arrest requires the S phase checkpoint that inhibits the S phase CDK. We propose that S phase arrest activates the S phase checkpoint blocking mitosis onset and inhibiting Cdc18 degradation, and that the stabilized Cdc18, in turn, anchors Rad3 to chromatin to ensure long-term checkpoint maintenance.
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48
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Hall JR, Kow E, Nevis KR, Lu CK, Luce KS, Zhong Q, Cook JG. Cdc6 stability is regulated by the Huwe1 ubiquitin ligase after DNA damage. Mol Biol Cell 2007; 18:3340-50. [PMID: 17567951 PMCID: PMC1951745 DOI: 10.1091/mbc.e07-02-0173] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The Cdc6 protein is an essential component of pre-replication complexes (preRCs), which assemble at origins of DNA replication during the G1 phase of the cell cycle. Previous studies have demonstrated that, in response to ionizing radiation, Cdc6 is ubiquitinated by the anaphase promoting complex (APC(Cdh1)) in a p53-dependent manner. We find, however, that DNA damage caused by UV irradiation or DNA alkylation by methyl methane sulfonate (MMS) induces Cdc6 degradation independently of p53. We further demonstrate that Cdc6 degradation after these forms of DNA damage is also independent of cell cycle phase, Cdc6 phosphorylation of the known Cdk target residues, or the Cul4/DDB1 and APC(Cdh1) ubiquitin E3 ligases. Instead Cdc6 directly binds a HECT-family ubiquitin E3 ligase, Huwe1 (also known as Mule, UreB1, ARF-BP1, Lasu1, and HectH9), and Huwe1 polyubiquitinates Cdc6 in vitro. Degradation of Cdc6 in UV-irradiated cells or in cells treated with MMS requires Huwe1 and is associated with release of Cdc6 from chromatin. Furthermore, yeast cells lacking the Huwe1 ortholog, Tom1, have a similar defect in Cdc6 degradation. Together, these findings demonstrate an important and conserved role for Huwe1 in regulating Cdc6 abundance after DNA damage.
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Affiliation(s)
- Jonathan R. Hall
- *Department of Biochemistry and Biophysics, School of Medicine and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599-7260
| | - Evelyn Kow
- Department of Molecular Genetics, Duke University Medical Center, Durham, NC 27710; and
| | - Kathleen R. Nevis
- *Department of Biochemistry and Biophysics, School of Medicine and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599-7260
| | - Chiajung Karen Lu
- Division of Biochemistry and Molecular Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3204
| | - K. Scott Luce
- *Department of Biochemistry and Biophysics, School of Medicine and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599-7260
| | - Qing Zhong
- Division of Biochemistry and Molecular Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3204
| | - Jeanette Gowen Cook
- *Department of Biochemistry and Biophysics, School of Medicine and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599-7260
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Fujita M. Cdt1 revisited: complex and tight regulation during the cell cycle and consequences of deregulation in mammalian cells. Cell Div 2006; 1:22. [PMID: 17042960 PMCID: PMC1621056 DOI: 10.1186/1747-1028-1-22] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Accepted: 10/17/2006] [Indexed: 12/31/2022] Open
Abstract
In eukaryotic cells, replication of genomic DNA initiates from multiple replication origins distributed on multiple chromosomes. To ensure that each origin is activated precisely only once during each S phase, a system has evolved which features periodic assembly and disassembly of essential pre-replication complexes (pre-RCs) at replication origins. The pre-RC assembly reaction involves the loading of a presumptive replicative helicase, the MCM2-7 complexes, onto chromatin by the origin recognition complex (ORC) and two essential factors, CDC6 and Cdt1. The eukaryotic cell cycle is driven by the periodic activation and inactivation of cyclin-dependent kinases (Cdks) and assembly of pre-RCs can only occur during the low Cdk activity period from late mitosis through G1 phase, with inappropriate re-assembly suppressed during S, G2, and M phases. It was originally suggested that inhibition of Cdt1 function after S phase in vertebrate cells is due to geminin binding and that Cdt1 hyperfunction resulting from Cdt1-geminin imbalance induces re-replication. However, recent progress has revealed that Cdt1 activity is more strictly regulated by two other mechanisms in addition to geminin: (1) functional and SCFSkp2-mediated proteolytic regulation through phosphorylation by Cdks; and (2) replication-coupled proteolysis mediated by the Cullin4-DDB1Cdt2 ubiquitin ligase and PCNA, an eukaryotic sliding clamp stimulating replicative DNA polymerases. The tight regulation implies that Cdt1 control is especially critical for the regulation of DNA replication in mammalian cells. Indeed, Cdt1 overexpression evokes chromosomal damage even without re-replication. Furthermore, deregulated Cdt1 induces chromosomal instability in normal human cells. Since Cdt1 is overexpressed in cancer cells, this could be a new molecular mechanism leading to carcinogenesis. In this review, recent insights into Cdt1 function and regulation in mammalian cells are discussed.
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Affiliation(s)
- Masatoshi Fujita
- Virology Division, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuohku, Tokyo 104-0045, Japan.
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50
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Tatsumi Y, Sugimoto N, Yugawa T, Narisawa-Saito M, Kiyono T, Fujita M. Deregulation of Cdt1 induces chromosomal damage without rereplication and leads to chromosomal instability. J Cell Sci 2006; 119:3128-40. [PMID: 16835273 DOI: 10.1242/jcs.03031] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The activity of human Cdt1 is negatively regulated by multiple mechanisms. This suggests that Cdt1 deregulation may have a deleterious effect. Indeed, it has been suggested that overexpression of Cdt1 can induce rereplication in cancer cells and that rereplication activates Ataxia-telangiectasia-mutated (ATM) kinase and/or ATM- and Rad3-related (ATR) kinase-dependent checkpoint pathways. In this report, we highlight a new and interesting aspect of Cdt1 deregulation: data from several different systems all strongly indicate that unregulated Cdt1 overexpression at pathophysiological levels can induce chromosomal damage other than rereplication in non-transformed cells. The most important finding in these studies is that deregulated Cdt1 induces chromosomal damage and activation of the ATM-Chk2 DNA damage checkpoint pathway even in quiescent cells. These Cdt1 activities are negatively regulated by cyclin A/Cdks, probably through modification by phosphorylation. Furthermore, we found that deregulated Cdt1 induces chromosomal instability in normal human cells. Since Cdt1 is overexpressed in cancer cells, this would be a new molecular mechanism leading to carcinogenesis.
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Affiliation(s)
- Yasutoshi Tatsumi
- Virology Division, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuohku, Tokyo 104-0045, Japan
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