1
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Bi X, Zhang M, Zhou J, Yan X, Cheng L, Luo L, Huang C, Yin Z. Phosphorylated Hsp27 promotes adriamycin resistance in breast cancer cells through regulating dual phosphorylation of c-Myc. Cell Signal 2023; 112:110913. [PMID: 37797796 DOI: 10.1016/j.cellsig.2023.110913] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/02/2023] [Accepted: 10/02/2023] [Indexed: 10/07/2023]
Abstract
Chemotherapy resistance of breast cancer cells is one of the major factors affecting patient survival rate. Heat shock protein 27 (Hsp27) is a member of the small heat shock protein family that has been reported to be associated with chemotherapy resistance in tumor cells, but the exact mechanism is not fully understood. Here, we explored the regulation of Hsp27 in adriamycin-resistant pathological conditions of breast cancer in vitro and in vivo. We found that overexpression of Hsp27 in MCF-7 breast cancer cells reversed DNA damage induced by adriamycin, and thereby reduced subsequent cell apoptosis. Non-phosphorylated Hsp27 accelerated ubiquitin-mediated degradation of c-Myc under normal physiological conditions. After stimulation with adriamycin, Hsp27 was phosphorylated and translocated from the cytoplasm into the nucleus, where phosphorylated Hsp27 upregulated c-Myc and Nijmegen breakage syndrome 1 (NBS1) protein levels thus leading to ATM activation. We further showed that phosphorylated Hsp27 promoted c-Myc nuclear import and stabilization by regulating T58/S62 phosphorylation of c-Myc through a protein phosphatase 2A (PP2A)-dependent mechanism. Collectively, the data presented in this study demonstrate that Hsp27, in its phosphorylation state, plays a critical role in adriamycin-resistant pathological conditions of breast cancer cells.
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Affiliation(s)
- Xiaowen Bi
- School of Basic Medical Sciences, Nanchang University, Nanchang 330006, China; Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Miao Zhang
- Institute of Microbiology, Jiangxi Academy of Sciences, Nanchang 330096, China
| | - Jinyi Zhou
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Xintong Yan
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Lixia Cheng
- School of Basic Medical Sciences, Nanchang University, Nanchang 330006, China
| | - Lan Luo
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China.
| | - Chunhong Huang
- School of Basic Medical Sciences, Nanchang University, Nanchang 330006, China.
| | - Zhimin Yin
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China.
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2
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Doha ZO, Sears RC. Unraveling MYC's Role in Orchestrating Tumor Intrinsic and Tumor Microenvironment Interactions Driving Tumorigenesis and Drug Resistance. PATHOPHYSIOLOGY 2023; 30:400-419. [PMID: 37755397 PMCID: PMC10537413 DOI: 10.3390/pathophysiology30030031] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 09/04/2023] [Accepted: 09/08/2023] [Indexed: 09/28/2023] Open
Abstract
The transcription factor MYC plays a pivotal role in regulating various cellular processes and has been implicated in tumorigenesis across multiple cancer types. MYC has emerged as a master regulator governing tumor intrinsic and tumor microenvironment interactions, supporting tumor progression and driving drug resistance. This review paper aims to provide an overview and discussion of the intricate mechanisms through which MYC influences tumorigenesis and therapeutic resistance in cancer. We delve into the signaling pathways and molecular networks orchestrated by MYC in the context of tumor intrinsic characteristics, such as proliferation, replication stress and DNA repair. Furthermore, we explore the impact of MYC on the tumor microenvironment, including immune evasion, angiogenesis and cancer-associated fibroblast remodeling. Understanding MYC's multifaceted role in driving drug resistance and tumor progression is crucial for developing targeted therapies and combination treatments that may effectively combat this devastating disease. Through an analysis of the current literature, this review's goal is to shed light on the complexities of MYC-driven oncogenesis and its potential as a promising therapeutic target.
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Affiliation(s)
- Zinab O. Doha
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA;
- Department of Medical Laboratories Technology, Taibah University, Al-Madinah 42353, Saudi Arabia
| | - Rosalie C. Sears
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA;
- Brenden-Colson Center for Pancreatic Care, Oregon Health & Science University, Portland, OR 97201, USA
- Knight Cancer Institute, Oregon Health & Science University, Portland, OR 97201, USA
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3
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Petroni M, La Monica V, Fabretti F, Augusto M, Battaglini D, Polonara F, Di Giulio S, Giannini G. The Multiple Faces of the MRN Complex: Roles in Medulloblastoma and Beyond. Cancers (Basel) 2023; 15:3599. [PMID: 37509263 PMCID: PMC10377613 DOI: 10.3390/cancers15143599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/09/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
Hypomorphic mutations in MRN complex genes are frequently found in cancer, supporting their role as oncosuppressors. However, unlike canonical oncosuppressors, MRN proteins are often overexpressed in tumor tissues, where they actively work to counteract DSBs induced by both oncogene-dependent RS and radio-chemotherapy. Moreover, at the same time, MRN genes are also essential genes, since the constitutive KO of each component leads to embryonic lethality. Therefore, even though it is paradoxical, MRN genes may work as oncosuppressive, oncopromoting, and essential genes. In this review, we discussed how alterations in the MRN complex impact the physiopathology of cancer, in light of our recent discoveries on the gene-dosage-dependent effect of NBS1 in Medulloblastoma. These updates aim to understand whether MRN complex can be realistically used as a prognostic/predictive marker and/or as a therapeutic target for the treatment of cancer patients in the future.
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Affiliation(s)
- Marialaura Petroni
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, 00161 Rome, Italy
| | - Veronica La Monica
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Francesca Fabretti
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Mariaconcetta Augusto
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Center for Life Nano- & Neuro-Science, Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Damiana Battaglini
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Francesca Polonara
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, 00161 Rome, Italy
| | - Stefano Di Giulio
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Giuseppe Giannini
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, 00161 Rome, Italy
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4
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ZSTK474 Sensitizes Glioblastoma to Temozolomide by Blocking Homologous Recombination Repair. BIOMED RESEARCH INTERNATIONAL 2022; 2022:8568528. [PMID: 35872860 PMCID: PMC9300311 DOI: 10.1155/2022/8568528] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/31/2022] [Accepted: 06/20/2022] [Indexed: 11/17/2022]
Abstract
Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Temozolomide (TMZ) is used as the standard chemotherapeutic agent for GBM but with limited success, and treatment failure is mainly due to tumor resistance. One of the leading causes of TMZ resistance is the upregulation of the DNA repair mechanism. Therefore, targeting the DNA damage response (DDR) is proposed to be an effective strategy to sensitize tumor cells to TMZ. In the present study, we demonstrated that the combined use of the PI3K inhibitor ZSTK474 and TMZ showed synergetic anticancer effects on human GBM cells in vitro and in vivo. The combination treatment led to significantly increased cell apoptosis and DNA double strand breaks (DSBs). In addition, a mechanistic study indicated that TMZ enhanced the homologous recombination (HR) repair efficiency in GBM cells, while ZSTK474 impaired HR repair by blocking the phosphorylation of ATM and the expression of BRCA1/2 and Rad51, thereby sensitizing GBM cells to TMZ. Moreover, TMZ activated the PI3K signaling pathway through upregulation of the PI3K catalytic subunits p110α and p110β and the phosphorylation of Akt. Meanwhile, ZSTK474 blocked the activity of the PI3K/Akt pathway. Taken together, our findings suggested that the combination of ZSTK474 and TMZ might be a potential therapeutic option for GBM.
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5
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Ahmadi SE, Rahimi S, Zarandi B, Chegeni R, Safa M. MYC: a multipurpose oncogene with prognostic and therapeutic implications in blood malignancies. J Hematol Oncol 2021; 14:121. [PMID: 34372899 PMCID: PMC8351444 DOI: 10.1186/s13045-021-01111-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/12/2021] [Indexed: 12/17/2022] Open
Abstract
MYC oncogene is a transcription factor with a wide array of functions affecting cellular activities such as cell cycle, apoptosis, DNA damage response, and hematopoiesis. Due to the multi-functionality of MYC, its expression is regulated at multiple levels. Deregulation of this oncogene can give rise to a variety of cancers. In this review, MYC regulation and the mechanisms by which MYC adjusts cellular functions and its implication in hematologic malignancies are summarized. Further, we also discuss potential inhibitors of MYC that could be beneficial for treating hematologic malignancies.
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Affiliation(s)
- Seyed Esmaeil Ahmadi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Rahimi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Bahman Zarandi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Rouzbeh Chegeni
- Medical Laboratory Sciences Program, College of Health and Human Sciences, Northern Illinois University, DeKalb, IL, USA.
| | - Majid Safa
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.
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Tang D, Huang T, Tian Q, Wang J. MYC/NBS1-Mediated DNA Damage Response is Involved in the Inhibitory Effect of Hydroxysafflor Yellow A on Glioma Cells. DRUG DESIGN DEVELOPMENT AND THERAPY 2021; 15:1749-1763. [PMID: 33953544 PMCID: PMC8089107 DOI: 10.2147/dddt.s288841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/30/2021] [Indexed: 02/02/2023]
Abstract
Background The role of Hydroxysafflor Yellow A (HSYA) in glioma is less studied, this research determined the effect of HSYA on glioma cells. Methods The expressions of MYC and NBS1 in glioma tissues were detected by bioinformatics analysis and verified by RT-qPCR. The target relationship between MYC and NBS1 was predicted by bioinformatics. After treating the cells with HSYA, silenced MYC, or overexpressed NBS1, the viability, apoptosis, proliferation, invasion, migration, and DNA damage of the glioma cells were detected by MTT, flow cytometry, colony formation, transwell, wound healing, and γH2AX immunofluorescence assays, respectively. IC50 of HSYA in glioma cells was analyzed by Probit regression analysis. The expressions of MYC, NBS1, factors related to migration, invasion, apoptosis, and DNA damage of the glioma cells were determined by Western blot or RT-qPCR. Results MYC and NBS1 were high-expressed in glioma, and NBS1 was targeted by MYC. HSYA and siRNA targeting MYC inhibited the cell viability, proliferation, invasion, migration, and induced the cell apoptosis of glioma cells. HSYA upregulated the expressions of MYC, γH2AX, E-Cadherin, Bax, and Cleaved-PARP1, stimulated the activation of NBS1, MRE11, RAD50, and ATM, and downregulated the expressions of N-Cadherin and Bcl2 in glioma cells. SiMYC decreased the IC50 of HSYA in the glioma cells, enhanced the sensitivity of glioma cells to HSYA, and inhibited the activation of NBS1 and ATM. NBS1 overexpression reversed the effect of siRNA targeting MYC on glioma cells. Conclusion MYC silencing inhibited the DNA damage response via regulation of NBS1, leading to DNA repair deficiency, and subsequently enhanced the sensitivity of glioma cells to HSYA.
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Affiliation(s)
- Dongfang Tang
- Department of Neurosurgery, Henan Provincial People's Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
| | - Tao Huang
- Department of Neurosurgery, The Second Affiliated Hospital of Air Force Military Medical University, Xi'an City, People's Republic of China
| | - Qilong Tian
- Department of Neurosurgery, The Second Affiliated Hospital of Air Force Military Medical University, Xi'an City, People's Republic of China
| | - Julei Wang
- Department of Neurosurgery, The Second Affiliated Hospital of Air Force Military Medical University, Xi'an City, People's Republic of China
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7
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Fan L, Xu S, Zhang F, Cui X, Fazli L, Gleave M, Clark DJ, Yang A, Hussain A, Rassool F, Qi J. Histone demethylase JMJD1A promotes expression of DNA repair factors and radio-resistance of prostate cancer cells. Cell Death Dis 2020; 11:214. [PMID: 32238799 PMCID: PMC7113292 DOI: 10.1038/s41419-020-2405-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 01/12/2023]
Abstract
The DNA damage response (DDR) pathway is a promising target for anticancer therapies. The androgen receptor and myeloblastosis transcription factors have been reported to regulate expression of an overlapping set of DDR genes in prostate cancer cells. Here, we found that histone demethylase JMJD1A regulates expression of a different set of DDR genes largely through c-Myc. Inhibition of JMJD1A delayed the resolution of γ-H2AX foci, reduced the formation of foci containing ubiquitin, 53BP1, BRCA1 or Rad51, and inhibited the reporter activity of double-strand break (DSB) repair. Mechanistically, JMJD1A regulated expression of DDR genes by increasing not only the level but also the chromatin recruitment of c-Myc through H3K9 demethylation. Further, we found that ubiquitin ligase HUWE1 induced the K27-/K29-linked noncanonical ubiquitination of JMJD1A at lysine-918. Ablation of the JMJD1A noncanonical ubiquitination lowered DDR gene expression, impaired DSB repair, and sensitized response of prostate cells to irradiation, topoisomerase inhibitors or PARP inhibitors. Thus, development of agents that target JMJD1A or its noncanonical ubiquitination may sensitize the response of prostate cancer to radiotherapy and possibly also genotoxic therapy.
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Affiliation(s)
- Lingling Fan
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
| | - Songhui Xu
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
| | - Fengbo Zhang
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.,Department of Urology, Beijing Friendship Hospital, Capital Medical University, 100050, Beijing, China
| | - Xiaolu Cui
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.,Department of Urology, First Hospital of China Medical University, 110001, Shenyang, China
| | - Ladan Fazli
- Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada
| | - Martin Gleave
- Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada
| | - David J Clark
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.,Department of Anatomy and Neurobiology, University of Maryland, Baltimore, MD, USA.,Department of Pathology, The Johns Hopkins University, Baltimore, MD, USA
| | - Austin Yang
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.,Department of Anatomy and Neurobiology, University of Maryland, Baltimore, MD, USA
| | - Arif Hussain
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.,Baltimore VA Medical Center, Baltimore, MD, USA
| | - Feyruz Rassool
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.,Department of Radiation Oncology, University of Maryland, Baltimore, MD, USA
| | - Jianfei Qi
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, USA. .,Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.
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8
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Zhen Y, Xiao R, Chen X, Yuan C, Sun Y, Li J. A non-synonymous polymorphism in NBS1 is associated with progression from chronic hepatitis B virus infection to hepatocellular carcinoma in a Chinese population. Onco Targets Ther 2018; 11:563-569. [PMID: 29416357 PMCID: PMC5790086 DOI: 10.2147/ott.s153538] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Nijmegen breakage syndrome 1 (NBS1) has a vital role in DNA double-strand break (DSB) repair, functioning as a sensor to identify and repair DNA damage and maintaining genomic stability by participating in the intra-S-phase checkpoint. Polymorphisms of NBS1 have been investigated in multiple cancers with variable results. To our best knowledge, no previous study has focused on the association between NBS1 single-nucleotide polymorphisms (SNPs) and hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). PATIENTS AND METHODS Five NBS1 SNPs were selected based on their potential functional impact. A hospital-based cohort, comprising 481 patients with HBV-related HCC, 508 patients with chronic hepatitis B virus infection (CHB), and 581 healthy controls, was recruited for genotyping analysis. RESULTS After quality control, four SNPs were successfully genotyped (rs10464867, rs1063053, rs1805794, and rs709816), none of which were significantly associated with HCC or CHB compared with those of healthy controls. Similarly, the combined HBV-infected group (including the HCC and CHB groups) exhibited no significant associations with these SNPs compared with healthy controls. In contrast, comparison of the frequency of rs1805794 between patients with CHB and those with HCC identified a significant association (P=2.99E-03, odds ratio =1.31, 95% confidence interval =1.10-1.56). CONCLUSION These findings suggest that, as a non-synonymous SNP, the rs1805794 C/G polymorphism may play a role in the progression from CHB to HCC.
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Affiliation(s)
- Ya’nan Zhen
- Department of General Surgery, Qianfoshan Hospital, Shandong University, Jinan
- Department of General Surgery, Affiliated Hospital of Shandong Academy of Medical Sciences, Jinan
| | - Ruixue Xiao
- Department of Pathology, Affiliated Hospital of Shandong Academy of Medical Sciences, Jinan
| | - Xing Chen
- Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan
| | - Changjin Yuan
- Department of Clinical Laboratory, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan
| | - Yanlai Sun
- Department of Gastrointestinal Cancer Surgery, Shandong Cancer Hospital Affiliated to Shandong University, Shandong Academy of Medical Sciences, Jinan, People’s Republic of China
| | - Jie Li
- Department of General Surgery, Qianfoshan Hospital, Shandong University, Jinan
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9
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Laribi K, Lemaire P, Sandrini J, Baugier de Materre A. Advances in the understanding and management of T-cell prolymphocytic leukemia. Oncotarget 2017; 8:104664-104686. [PMID: 29262669 PMCID: PMC5732835 DOI: 10.18632/oncotarget.22272] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 08/27/2017] [Indexed: 12/02/2022] Open
Abstract
T-prolymphocytic leukemia (T-PLL) is a rare T-cell neoplasm with an aggressive clinical course. Leukemic T-cells exhibit a post-thymic T-cell phenotype (Tdt-, CD1a-, CD5+, CD2+ and CD7+) and are generally CD4+/CD8-, but CD4+/CD8+ or CD8+/CD4- T-PLL have also been reported. The hallmark of T-PLL is the rearrangement of chromosome 14 involving genes for the subunits of the T-cell receptor (TCR) complex, leading to overexpression of the proto-oncogene TCL1. In addition, molecular analysis shows that T-PLL exhibits substantial mutational activation of the IL2RG-JAK1-JAK3-, STAT5B axis. T-PLL patients have a poor prognosis, due to a poor response to conventional chemotherapy. Monoclonal antibody therapy with antiCD52-alemtuzumab has considerably improved outcomes, but the responses to treatment are transient; hence, patients who achieve a response to therapy are considered for stem cell transplantation (SCT). This combined approach has extended the median survival to four years or more. Nevertheless, new approaches using well-tolerated therapies that target growth and survival signals are needed for most patients unable to receive intensive chemotherapy.
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Affiliation(s)
- Kamel Laribi
- Department of Hematology, Centre Hospitalier du Mans, Le Mans, France
| | - Pierre Lemaire
- Laboratory of Biology and Hematology, Centre Hospitalier du Mans, Le Mans, France
| | - Jeremy Sandrini
- Laboratory of Anatomopathology, Centre Hospitalier du Mans, Le Mans, France
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10
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Cui FM, Sun XJ, Huang CC, Chen Q, He YM, Zhang SM, Guan H, Song M, Zhou PK, Hou J. Inhibition of c-Myc expression accounts for an increase in the number of multinucleated cells in human cervical epithelial cells. Oncol Lett 2017; 14:2878-2886. [PMID: 28928827 PMCID: PMC5588452 DOI: 10.3892/ol.2017.6554] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 03/23/2017] [Indexed: 01/06/2023] Open
Abstract
The present study aimed to explore the mechanisms by which c-Myc is involved in mitotic catastrophe. HeLa-630 is a cell line stably silenced for c-Myc expression that was established in the laboratory of the School of Radiation Medicine and Protection. Multinucleated cells were observed in this line, and gene expression analysis was utilized to examine differences in gene expression in these cells compared with in the control cells transfected with the control plasmid. Gene ontology analysis was performed for differentially expressed genes. Expression profile analyses revealed that cells with silenced c-Myc exhibited abnormal expression patterns of genes involved in various functions, including the regulation of microtubule nucleation, centrosome duplication, the formation of pericentriolar material, DNA synthesis and metabolism, protein metabolism and the regulation of ion concentrations. Pathway analyses of differentially expressed genes demonstrated that these genes were primarily involved in diverse signal transduction pathways, including not only the adherens junction pathway, the transforming growth factor-β signaling pathway and the Wnt signaling pathway, among others, but also signaling pathways with roles in cytokine and immune regulation. The proportion of multinucleated cells with multipolar spindles was significantly higher in silenced c-Myc cells as compared with the control cells, and this discrepancy became more pronounced following cell irradiation. The inhibition of c-Myc in tumors may account for the radiosensitization of certain tumor cell types.
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Affiliation(s)
- Feng Mei Cui
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China.,Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Xiu Jin Sun
- Department of Radiation Oncology, Jiangsu Cancer Hospital, Nanjing, Jiangsu 210000, P.R. China
| | - Cheng Cheng Huang
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Qiu Chen
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China.,Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Yong Ming He
- Department of Cardiology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Shi Meng Zhang
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, Beijing 100850, P.R. China
| | - Hua Guan
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, Beijing 100850, P.R. China
| | - Man Song
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Ping Kun Zhou
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China.,Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, Beijing 100850, P.R. China
| | - Jun Hou
- Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai 200032, P.R. China
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11
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Kumari A, Folk WP, Sakamuro D. The Dual Roles of MYC in Genomic Instability and Cancer Chemoresistance. Genes (Basel) 2017; 8:genes8060158. [PMID: 28590415 PMCID: PMC5485522 DOI: 10.3390/genes8060158] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/31/2017] [Accepted: 06/01/2017] [Indexed: 12/18/2022] Open
Abstract
Cancer is associated with genomic instability and aging. Genomic instability stimulates tumorigenesis, whereas deregulation of oncogenes accelerates DNA replication and increases genomic instability. It is therefore reasonable to assume a positive feedback loop between genomic instability and oncogenic stress. Consistent with this premise, overexpression of the MYC transcription factor increases the phosphorylation of serine 139 in histone H2AX (member X of the core histone H2A family), which forms so-called γH2AX, the most widely recognized surrogate biomarker of double-stranded DNA breaks (DSBs). Paradoxically, oncogenic MYC can also promote the resistance of cancer cells to chemotherapeutic DNA-damaging agents such as cisplatin, clearly implying an antagonistic role of MYC in genomic instability. In this review, we summarize the underlying mechanisms of the conflicting functions of MYC in genomic instability and discuss when and how the oncoprotein exerts the contradictory roles in induction of DSBs and protection of cancer-cell genomes.
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Affiliation(s)
- Alpana Kumari
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
- Tumor Signaling and Angiogenesis Program, Georgia Cancer Center, Augusta University, Augusta, GA 30912, USA.
| | - Watson P Folk
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
- Tumor Signaling and Angiogenesis Program, Georgia Cancer Center, Augusta University, Augusta, GA 30912, USA.
- Biochemistry and Cancer Biology Program, The Graduate School, Augusta University, Augusta, GA 30912, USA.
| | - Daitoku Sakamuro
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
- Tumor Signaling and Angiogenesis Program, Georgia Cancer Center, Augusta University, Augusta, GA 30912, USA.
- Biochemistry and Cancer Biology Program, The Graduate School, Augusta University, Augusta, GA 30912, USA.
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12
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Withaferin-A kills cancer cells with and without telomerase: chemical, computational and experimental evidences. Cell Death Dis 2017; 8:e2755. [PMID: 28425984 PMCID: PMC5477593 DOI: 10.1038/cddis.2017.33] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 12/28/2016] [Accepted: 01/03/2017] [Indexed: 01/03/2023]
Abstract
Maintenance of telomere length is the most consistent attribute of cancer cells. Tightly connected to their capacity to overcome replicative mortality, it is achieved either by activation of telomerase or an Alternative mechanism of Lengthening of Telomeres (ALT). Disruption of either of these mechanisms has been shown to induce DNA damage signalling leading to senescence or apoptosis. Telomerase inhibitors are considered as potential anticancer drugs but are ineffective for ALT cancers (~15% of all cancers). Withaferin-A (Wi-A), a major constituent of the medicinal plant, Withania somnifera (Ashwagandha), has been shown to exert anti-tumour activity. However, its effect on either telomerase or ALT mechanisms has not been investigated. Here, by using isogenic cancer cells with/without telomerase, we found that Wi-A caused stronger cytotoxicity to ALT cells. It was associated with inhibition of ALT-associated promyelocytic leukemia nuclear bodies, an established marker of ALT. Comparative analyses of telomerase positive and ALT cells revealed that Wi-A caused stronger telomere dysfunction and upregulation of DNA damage response in ALT cells. Molecular computational and experimental analyses revealed that Wi-A led to Myc-Mad mediated transcriptional suppression of NBS-1, an MRN complex protein that is an essential component of the ALT mechanism. The results suggest that Wi-A could be a new candidate drug for ALT cancers.
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SGO1 is involved in the DNA damage response in MYCN-amplified neuroblastoma cells. Sci Rep 2016; 6:31615. [PMID: 27539729 PMCID: PMC4990925 DOI: 10.1038/srep31615] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/25/2016] [Indexed: 11/08/2022] Open
Abstract
Shugoshin 1 (SGO1) is required for accurate chromosome segregation during mitosis and meiosis; however, its other functions, especially at interphase, are not clearly understood. Here, we found that downregulation of SGO1 caused a synergistic phenotype in cells overexpressing MYCN. Downregulation of SGO1 impaired proliferation and induced DNA damage followed by a senescence-like phenotype only in MYCN-overexpressing neuroblastoma cells. In these cells, SGO1 knockdown induced DNA damage, even during interphase, and this effect was independent of cohesin. Furthermore, MYCN-promoted SGO1 transcription and SGO1 expression tended to be higher in MYCN- or MYC-overexpressing cancers. Together, these findings indicate that SGO1 plays a role in the DNA damage response in interphase. Therefore, we propose that SGO1 represents a potential molecular target for treatment of MYCN-amplified neuroblastoma.
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Petroni M, Sardina F, Heil C, Sahún-Roncero M, Colicchia V, Veschi V, Albini S, Fruci D, Ricci B, Soriani A, Di Marcotullio L, Screpanti I, Gulino A, Giannini G. The MRN complex is transcriptionally regulated by MYCN during neural cell proliferation to control replication stress. Cell Death Differ 2016; 23:197-206. [PMID: 26068589 PMCID: PMC4716299 DOI: 10.1038/cdd.2015.81] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 04/12/2015] [Accepted: 05/18/2015] [Indexed: 12/27/2022] Open
Abstract
The MRE11/RAD50/NBS1 (MRN) complex is a major sensor of DNA double strand breaks, whose role in controlling faithful DNA replication and preventing replication stress is also emerging. Inactivation of the MRN complex invariably leads to developmental and/or degenerative neuronal defects, the pathogenesis of which still remains poorly understood. In particular, NBS1 gene mutations are associated with microcephaly and strongly impaired cerebellar development, both in humans and in the mouse model. These phenotypes strikingly overlap those induced by inactivation of MYCN, an essential promoter of the expansion of neuronal stem and progenitor cells, suggesting that MYCN and the MRN complex might be connected on a unique pathway essential for the safe expansion of neuronal cells. Here, we show that MYCN transcriptionally controls the expression of each component of the MRN complex. By genetic and pharmacological inhibition of the MRN complex in a MYCN overexpression model and in the more physiological context of the Hedgehog-dependent expansion of primary cerebellar granule progenitor cells, we also show that the MRN complex is required for MYCN-dependent proliferation. Indeed, its inhibition resulted in DNA damage, activation of a DNA damage response, and cell death in a MYCN- and replication-dependent manner. Our data indicate the MRN complex is essential to restrain MYCN-induced replication stress during neural cell proliferation and support the hypothesis that replication-born DNA damage is responsible for the neuronal defects associated with MRN dysfunctions.
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Affiliation(s)
- M Petroni
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - F Sardina
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - C Heil
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - M Sahún-Roncero
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - V Colicchia
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - V Veschi
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - S Albini
- Paediatric Haematology/Oncology Department, IRCCS, Ospedale Pediatrico Bambino Gesù, 00165 Rome, Italy
| | - D Fruci
- Paediatric Haematology/Oncology Department, IRCCS, Ospedale Pediatrico Bambino Gesù, 00165 Rome, Italy
| | - B Ricci
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - A Soriani
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - L Di Marcotullio
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - I Screpanti
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - A Gulino
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - G Giannini
- Istituto Pasteur-Fondazione Cenci Bolognetti, Deptartment of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
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Cui F, Fan R, Chen Q, He Y, Song M, Shang Z, Zhang S, Zhu W, Cao J, Guan H, Zhou PK. The involvement of c-Myc in the DNA double-strand break repair via regulating radiation-induced phosphorylation of ATM and DNA-PKcs activity. Mol Cell Biochem 2015; 406:43-51. [PMID: 26049366 DOI: 10.1007/s11010-015-2422-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 04/20/2015] [Indexed: 10/23/2022]
Abstract
Deregulation of c-Myc often occurs in various human cancers, which not only contributes to the genesis and progression of cancers but also affects the outcomes of cancer radio- or chemotherapy. In this study, we have investigated the function of c-Myc in the repair of DNA double-strand break (DSB) induced by γ-ray irradiation. A c-Myc-silenced Hela-630 cell line was generated from HeLa cells using RNA interference technology. The DNA DSBs were detected by γ-H2AX foci, neutral comet assay and pulsed-field gel electrophoresis. We found that the capability of DNA DSB repair in Hela-630 cells was significantly reduced, and the repair kinetics of DSB was delayed as compared to the control Hela-NC cells. Silence of c-myc sensitized the cellular sensitivity to ionizing radiation. The phosphorylated c-Myc (Thr58/pSer62) formed the consistent co-localisation foci with γ-H2AX as well as the phosphorylated DNA-PKcs/S2056 in the irradiated cells. Moreover, depression of c-Myc largely attenuated the ionizing radiation-induced phosphorylation of the ataxia telangiectasia mutated (ATM) and decreased the in vitro kinase activity of DNA-PKcs. Taken together, our results demonstrated that c-Myc protein functions in the process of DNA double-strand break repair, at least partially, through affecting the ATM phosphorylation and DNA-PKcs kinase activity. The overexpression of c-Myc in tumours can account for the radioresistance of some tumour cell types.
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Affiliation(s)
- Fengmei Cui
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, 215123, China
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Kuo YC, Wu HT, Hung JJ, Chou TY, Teng SC, Wu KJ. Nijmegen breakage syndrome protein 1 (NBS1) modulates hypoxia inducible factor-1α (HIF-1α) stability and promotes in vitro migration and invasion under ionizing radiation. Int J Biochem Cell Biol 2015; 64:229-38. [PMID: 25959252 DOI: 10.1016/j.biocel.2015.04.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 04/06/2015] [Accepted: 04/28/2015] [Indexed: 10/23/2022]
Abstract
Hypoxia-inducible factor (HIF) is a heterodimer transcription factor complex that monitors the cellular response to the oxygen levels in cells. Hypoxia-inducible factor-1α (HIF-1α) has been shown to be stabilized by ionizing radiation (IR) and its stabilization promotes tumor progression and metastasis. Nijmegen breakage syndrome protein 1 (NBS1), a component of the MRE11-RAD50-NBS1 complex, plays an important role in the cellular response to DNA damage but its overexpression contributes to transformation and has been found to correlate with metastasis. However, whether NBS1 participates in IR-induced metastasis needs to be further determined. The aim of this study is to investigate whether radiation-induced HIF-1α stabilization is regulated by NBS1 and thereby promotes tumor cell migration/invasion. Here, we show that both NBS1 and HIF-1α expression are up-regulated after exposure to IR, and NBS1 increases HIF-1α expression at the protein level. In addition, IR treatment promotes the epithelial-mesenchymal transition (EMT) and in vitro cell migration and invasion activity, which could be abolished by suppression of NBS1. Furthermore, NBS1 directly interacts with HIF-1α and reduces the ubiquitination of HIF-1α⋅ Co-expression of HIF-1α and NBS1 in primary tumors of patients with lung adenocarcinoma correlates with a worse prognosis. These results provide a new function of NBS1 in stabilizing HIF-1α under IR, which leads to enhanced cancer cell migration and invasion.
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Affiliation(s)
- Yi-Chih Kuo
- Institute of Biochemistry & Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan
| | - Han-Tsang Wu
- Research Center for Tumor Medical Science, Graduate Institute of Cancer Biology, China Medical University, Taichung 404, Taiwan
| | - Jung-Jyh Hung
- Institute of Clinical Medicine, National Yang-Ming University, Taipei 112, Taiwan; Division of Thoracic Surgery, Dept. of Surgery, Taipei Veterans General Hospital, Taipei 112, Taiwan
| | - Teh-Ying Chou
- Institute of Clinical Medicine, National Yang-Ming University, Taipei 112, Taiwan; Dept of Pathology, Taipei Veterans General Hospital, Taipei 112, Taiwan
| | - Shu-Chun Teng
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Kou-Juey Wu
- Institute of Biochemistry & Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan; Research Center for Tumor Medical Science, Graduate Institute of Cancer Biology, China Medical University, Taichung 404, Taiwan.
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17
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Wu J, Starr S. Low-fidelity compensatory backup alternative DNA repair pathways may unify current carcinogenesis theories. Future Oncol 2015; 10:1239-53. [PMID: 24947263 DOI: 10.2217/fon.13.272] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The somatic mutation carcinogenesis theory has dominated for decades. The alternative theory, tissue organization field theory, argues that the development of cancer is determined by the surrounding microenvironment. However, neither theory can explain all features of cancer. As cancers share the features of uncontrolled proliferation and genomic instability, they are likely to have the same pathogenesis. It has been found that various DNA repair pathways within a cell crosstalk with one another, forming a DNA repair network. When one DNA repair pathways is defective, the others may work as compensatory backups. The latter pathways are explored for synthetic lethal anticancer therapy. In this article, we extend the concept of compensatory alternative DNA repair to unify the theories. We propose that the microenvironmental stress can activate low-fidelity compensatory alternative DNA repair, causing mutations. If the mutation occurs to a DNA repair gene, this secondarily mutated gene can lead to even more mutated genes, including those related to other DNA repair pathways, eventually destabilizing the genome. Therefore, the low-fidelity compensatory alternative DNA repair may mediate microenvironment-dependent carcinogenesis. The proposal seems consistent with the view of evolution: the environmental stress causes mutations to adapt to the changing environment.
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Affiliation(s)
- Jiaxi Wu
- Central Laboratories, Xuhui Central Hospital, Shanghai Clinical Research Center, Chinese Academy of Sciences, 966 Middle Huaihai Road, Shanghai 200031, China
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18
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Radiation therapy for glioma stem cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 853:85-110. [PMID: 25895709 DOI: 10.1007/978-3-319-16537-0_6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Radiation therapy is the most effective adjuvant treatment modality for virtually all patients with high-grade glioma. Its ability to improve patient survival has been recognized for decades. Cancer stem cells provide new insights into how tumor biology is affected by radiation and the role that this cell population can play in disease recurrence. Glioma stem cells possess a variety of intracellular mechanisms to resist and even flourish in spite of radiation, and their proliferation and maintenance appear tied to supportive stimuli from the tumor microenvironment. This chapter reviews the basis for our current use of radiation to treat high-grade gliomas, and addresses this model in the context of therapeutically resistant stem cells. We discuss the available evidence highlighting current clinical efforts to improve radiosensitivity, and newer targets worthy of further development.
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The associations between immunity-related genes and breast cancer prognosis in Korean women. PLoS One 2014; 9:e103593. [PMID: 25075970 PMCID: PMC4116221 DOI: 10.1371/journal.pone.0103593] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 07/02/2014] [Indexed: 12/15/2022] Open
Abstract
We investigated the role of common genetic variation in immune-related genes on breast cancer disease-free survival (DFS) in Korean women. 107 breast cancer patients of the Seoul Breast Cancer Study (SEBCS) were selected for this study. A total of 2,432 tag single nucleotide polymorphisms (SNPs) in 283 immune-related genes were genotyped with the GoldenGate Oligonucleotide pool assay (OPA). A multivariate Cox-proportional hazard model and polygenic risk score model were used to estimate the effects of SNPs on breast cancer prognosis. Harrell’s C index was calculated to estimate the predictive accuracy of polygenic risk score model. Subsequently, an extended gene set enrichment analysis (GSEA-SNP) was conducted to approximate the biological pathway. In addition, to confirm our results with current evidence, previous studies were systematically reviewed. Sixty-two SNPs were statistically significant at p-value less than 0.05. The most significant SNPs were rs1952438 in SOCS4 gene (hazard ratio (HR) = 11.99, 95% CI = 3.62–39.72, P = 4.84E-05), rs2289278 in TSLP gene (HR = 4.25, 95% CI = 2.10–8.62, P = 5.99E-05) and rs2074724 in HGF gene (HR = 4.63, 95% CI = 2.18–9.87, P = 7.04E-05). In the polygenic risk score model, the HR of women in the 3rd tertile was 6.78 (95% CI = 1.48–31.06) compared to patients in the 1st tertile of polygenic risk score. Harrell’s C index was 0.813 with total patients and 0.924 in 4-fold cross validation. In the pathway analysis, 18 pathways were significantly associated with breast cancer prognosis (P<0.1). The IL-6R, IL-8, IL-10RB, IL-12A, and IL-12B was associated with the prognosis of cancer in data of both our study and a previous study. Therefore, our results suggest that genetic polymorphisms in immune-related genes have relevance to breast cancer prognosis among Korean women.
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Abstract
MYC dysregulation initiates a dynamic process of genomic instability that is linked to tumor initiation. Early studies using MYC-carrying retroviruses showed that these viruses were potent transforming agents. Cell culture models followed that addressed the role of MYC in transformation. With the advent of MYC transgenic mice, it became obvious that MYC deregulation alone was sufficient to initiate B-cell neoplasia in mice. More than 70% of all tumors have some form of c-MYC gene dysregulation, which affects gene regulation, microRNA expression profiles, large genomic amplifications, and the overall organization of the nucleus. These changes set the stage for the dynamic genomic rearrangements that are associated with cellular transformation.
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Affiliation(s)
- Alexandra Kuzyk
- Manitoba Institute of Cell Biology, University of Manitoba, CancerCare Manitoba, Winnipeg, Manitoba R3E 0V9, Canada
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21
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Murakami-Tonami Y, Kishida S, Takeuchi I, Katou Y, Maris JM, Ichikawa H, Kondo Y, Sekido Y, Shirahige K, Murakami H, Kadomatsu K. Inactivation of SMC2 shows a synergistic lethal response in MYCN-amplified neuroblastoma cells. Cell Cycle 2014; 13:1115-31. [PMID: 24553121 PMCID: PMC4013162 DOI: 10.4161/cc.27983] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The condensin complex is required for chromosome condensation during mitosis; however, the role of this complex during interphase is unclear. Neuroblastoma is the most common extracranial solid tumor of childhood, and it is often lethal. In human neuroblastoma, MYCN gene amplification is correlated with poor prognosis. This study demonstrates that the gene encoding the condensin complex subunit SMC2 is transcriptionally regulated by MYCN. SMC2 also transcriptionally regulates DNA damage response genes in cooperation with MYCN. Downregulation of SMC2 induced DNA damage and showed a synergistic lethal response in MYCN-amplified/overexpression cells, leading to apoptosis in human neuroblastoma cells. Finally, this study found that patients bearing MYCN-amplified tumors showed improved survival when SMC2 expression was low. These results identify novel functions of SMC2 in DNA damage response, and we propose that SMC2 (or the condensin complex) is a novel molecular target for the treatment of MYCN-amplified neuroblastoma.
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Affiliation(s)
- Yuko Murakami-Tonami
- Department of Molecular Biology; Nagoya University Graduate School of Medicine; Nagoya, Japan
| | - Satoshi Kishida
- Department of Molecular Biology; Nagoya University Graduate School of Medicine; Nagoya, Japan
| | - Ichiro Takeuchi
- Department of Computer Science/Scientific and Engineering Simulation; Nagoya Institute of Technology; Nagoya, Japan
| | - Yuki Katou
- Laboratory of Genome Structure & Function; Institute of Molecular and Cellular Biosciences; The University of Tokyo; Tokyo, Japan
| | - John M Maris
- Department of Pediatrics and Center for Childhood Cancer Research; Children's Hospital of Philadelphia; University of Pennsylvania; Philadelphia, PA USA
| | | | - Yutaka Kondo
- Division of Molecular Oncology; Aichi Cancer Center Research Institute; Nagoya, Japan; Division of Epigenomics; Aichi Cancer Center Research Institute; Nagoya, Japan
| | - Yoshitaka Sekido
- Division of Molecular Oncology; Aichi Cancer Center Research Institute; Nagoya, Japan
| | - Katsuhiko Shirahige
- Laboratory of Genome Structure & Function; Institute of Molecular and Cellular Biosciences; The University of Tokyo; Tokyo, Japan
| | - Hiroshi Murakami
- Department of Biological Science; Faculty of Science and Engineering; Chuo University; Tokyo, Japan
| | - Kenji Kadomatsu
- Department of Molecular Biology; Nagoya University Graduate School of Medicine; Nagoya, Japan
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Abstract
DNA damage response genes play vital roles in the maintenance of a healthy genome. Defects in cell cycle checkpoint and DNA repair genes, especially mutation or aberrant downregulation, are associated with a wide spectrum of human disease, including a predisposition to the development of neurodegenerative conditions and cancer. On the other hand, upregulation of DNA damage response and repair genes can also cause cancer, as well as increase resistance of cancer cells to DNA damaging therapy. In recent years, it has become evident that many of the genes involved in DNA damage repair have additional roles in tumorigenesis, most prominently by acting as transcriptional (co-)factors. Although defects in these genes are causally connected to tumor initiation, their role in tumor progression is more controversial and it seems to depend on tumor type. In some tumors like melanoma, cell cycle checkpoint/DNA repair gene upregulation is associated with tumor metastasis, whereas in a number of other cancers the opposite has been observed. Several genes that participate in the DNA damage response, such as RAD9, PARP1, BRCA1, ATM and TP53 have been associated with metastasis by a number of in vitro biochemical and cellular assays, by examining human tumor specimens by immunohistochemistry or by DNA genome-wide gene expression profiling. Many of these genes act as transcriptional effectors to regulate other genes implicated in the pathogenesis of cancer. Furthermore, they are aberrantly expressed in numerous human tumors and are causally related to tumorigenesis. However, whether the DNA damage repair function of these genes is required to promote metastasis or another activity is responsible (e.g., transcription control) has not been determined. Importantly, despite some compelling in vitro evidence, investigations are still needed to demonstrate the role of cell cycle checkpoint and DNA repair genes in regulating metastatic phenotypes in vivo.
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Affiliation(s)
- Constantinos G. Broustas
- Center for Radiological Research, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Howard B. Lieberman
- Center for Radiological Research, Columbia University College of Physicians and Surgeons, New York, New York 10032
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032
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Wang Y, Li M, Long J, Shi XY, Li Q, Chen J, Tong WM, Jia JD, Huang J. Clinical significance of increased expression of Nijmegen breakage syndrome gene (NBS1) in human primary liver cancer. Hepatol Int 2014. [PMID: 26202506 DOI: 10.1007/s12072-013-9500-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE As a DNA repair-associated gene essential for maintaining genomic instability, Nijmegen breakage syndrome gene (NBS1), codes for a protein, Nbs1(p95/Nibrin), involved in the processing/repair of DNA double-strand breaks. The aim of this study is to investigate the molecular alteration of Nbs1 in human primary liver cancer, including HBV-associated hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). METHODS The expression levels of Nbs1 in 110 cases of primary liver cancer, including 85 HCCs and 25 ICCs, were detected by immunohistochemistry, real-time RT-PCR and Western blot analysis. The percentage of Ki-67 antigen-positive cells and the level of phosphorylated histone H2AX (γ-H2AX) were detected to evaluate the relationship of Nbs1 expression with proliferation and the degree of DNA damage in HCC cells. RESULTS Increased Nbs1 expression was observed in tumor compared to corresponding adjacent non-tumor tissue in 54.6 and 47.3 % of HCC cases detected with frozen tissues and paraffin sections. Higher frequency of increased Nbs1 expression was shown in poorly differentiated HCCs (p = 0.0265) and in all poorly differentiated ICCs, indicating the increased Nbs1 expression is associated with the degree of malignancy of HCC cells. Moreover, the percentage of Ki-67-positive cells and the level of γ-H2AX correlate well with increased Nbs1 expression in HCC cases, suggesting an activated DNA damage response in proliferating HCC cells with increased Nbs1 expression. CONCLUSION Increased Nbs1 expression might play a significant role in liver cancer progression, and the status of Nbs1 expression might be helpful for evaluation of the degree of malignancy of primary liver cancer.
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Affiliation(s)
- Yan Wang
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Beijing, 100050, China
| | - Man Li
- Department of Pathology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Jiang Long
- Minimally Invasive Hepatobiliary Cancer Center, Beijing You-An Hospital, Capital Medical University, Beijing, China
| | - Xiao-Yan Shi
- Department of Pathology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Qian Li
- Department of Oncological Science, Mount Sinai School of Medicine, New York, NY, USA
| | - Jia Chen
- Department of Oncological Science, Mount Sinai School of Medicine, New York, NY, USA
| | - Wei-Min Tong
- Department of Pathology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Ji-Dong Jia
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Beijing, 100050, China.
| | - Jian Huang
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Beijing, 100050, China.
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FOXM1 targets NBS1 to regulate DNA damage-induced senescence and epirubicin resistance. Oncogene 2013; 33:4144-55. [PMID: 24141789 PMCID: PMC3969838 DOI: 10.1038/onc.2013.457] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/09/2013] [Accepted: 09/16/2013] [Indexed: 12/25/2022]
Abstract
FOXM1 is implicated in genotoxic drug resistance but its mechanism of action remains elusive. We show here that FOXM1-depletion can sensitize breast cancer cells and MEFs into entering epirubicin-induced senescence, with the loss of long-term cell proliferation ability, the accumulation of γH2AX foci, and the induction of senescence-associated β-galactosidase activity and cell morphology. Conversely, reconstitution of FOXM1 in FOXM1-deficient MEFs alleviates the accumulation of senescence-associated γH2AX foci. We also demonstrate that FOXM1 regulates NBS1 at the transcriptional level through an FHRE on its promoter. Like FOXM1, NBS1 is overexpressed in the epirubicin-resistant MCF-7EpiR cells and its expression level is low but inducible by epirubicin in MCF-7 cells. Consistently, overexpression of FOXM1 augmented and FOXM1 depletion reduced NBS1 expression and epirubicin-induced ATM phosphorylation in breast cancer cells. Together these findings suggest that FOXM1 increases NBS1 expression and ATM phosphorylation, possibly through increasing the levels of the MRN(MRE11/RAD50/NBS1) complex. Consistent with this idea, the loss of P-ATM induction by epirubicin in the NBS1-deficient NBS1-LBI fibroblasts can be rescued by NBS1 reconstitution. Resembling FOXM1, NBS1 depletion also rendered MCF-7 and MCF-7EpiR cells more sensitive to epirubicin-induced cellular senescence. In agreement, the DNA repair-defective and senescence phenotypes in FOXM1-deficent cells can be effectively rescued by overexpression of NBS1. Moreover, overexpression of NBS1 and FOXM1 similarly enhanced and their depletion downregulated HR DNA repair activity. Crucially, overexpression of FOXM1 failed to augment HR activity in the background of NBS1 depletion, demonstrating that NBS1 is indispensable for the HR function of FOXM1. The physiological relevance of the regulation of NBS1 expression by FOXM1 is further underscored by the strong and significant correlation between nuclear FOXM1 and total NBS1 expression in breast cancer patient samples, further suggesting that NBS1 as a key FOXM1 target gene involved in DNA damage response, genotoxic drug resistance and DNA damage-induced senescence.
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25
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Kefala M, Papageorgiou SG, Kontos CK, Economopoulou P, Tsanas A, Pappa V, Panayiotides IG, Gorgoulis VG, Patsouris E, Foukas PG. Increased expression of phosphorylated NBS1, a key molecule of the DNA damage response machinery, is an adverse prognostic factor in patients with de novo myelodysplastic syndromes. Leuk Res 2013; 37:1576-82. [PMID: 24054861 DOI: 10.1016/j.leukres.2013.08.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/22/2013] [Accepted: 08/25/2013] [Indexed: 01/02/2023]
Abstract
The expression of activated forms of key proteins of the DNA damage response machinery (pNBS1, pATM and γH2AX) was assessed by means of immunohistochemistry in bone marrow biopsies of 74 patients with de novo myelodysplastic syndromes (MDS) and compared with 15 cases of de novo acute myeloid leukemia (AML) and 20 with reactive bone marrow histology. Expression levels were significantly increased in both MDS and AML, compared to controls, being higher in high-risk than in low-risk MDS. Increased pNBS1 and γH2AX expression possessed a significant negative prognostic impact for overall survival in MDS patients, whereas pNBS1 was an independent marker of poor prognosis.
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Affiliation(s)
- Maria Kefala
- 2nd Department of Pathology, University of Athens Medical School, "Attikon" University Hospital, Chaidari, Greece
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Wang JQ, Chen JH, Chen YC, Chen MY, Hsieh CY, Teng SC, Wu KJ. Interaction between NBS1 and the mTOR/Rictor/SIN1 complex through specific domains. PLoS One 2013; 8:e65586. [PMID: 23762398 PMCID: PMC3675082 DOI: 10.1371/journal.pone.0065586] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 04/26/2013] [Indexed: 11/24/2022] Open
Abstract
Nijmegen breakage syndrome (NBS) is a chromosomal-instability syndrome. The NBS gene product, NBS1 (p95 or nibrin), is a part of the Mre11-Rad50-NBS1 complex. SIN1 is a component of the mTOR/Rictor/SIN1 complex mediating the activation of Akt. Here we show that NBS1 interacted with mTOR, Rictor, and SIN1. The specific domains of mTOR, Rictor, or SIN1 interacted with the internal domain (a.a. 221-402) of NBS1. Sucrose density gradient showed that NBS1 was located in the same fractions as the mTOR/Rictor/SIN1 complex. Knockdown of NBS1 decreased the levels of phosphorylated Akt and its downstream targets. Ionizing radiation (IR) increased the NBS1 levels and activated Akt activity. These results demonstrate that NBS1 interacts with the mTOR/Rictor/SIN1 complex through the a.a. 221–402 domain and contributes to the activation of Akt activity.
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Affiliation(s)
- Jian-Qiu Wang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
- Institute of Aging Research, Department of Basic Medical Science, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Jian-Hong Chen
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Yen-Chung Chen
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Mei-Yu Chen
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Chia-Ying Hsieh
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Shu-Chun Teng
- Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kou-Juey Wu
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
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WAN ROWENA, WU JIANCHUN, BALOUE KAITRINK, CROWE DAVIDL. Regulation of the Nijmegen breakage syndrome 1 gene NBS1 by c-myc, p53 and coactivators mediates estrogen protection from DNA damage in breast cancer cells. Int J Oncol 2012; 42:712-20. [DOI: 10.3892/ijo.2012.1757] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 12/04/2012] [Indexed: 11/05/2022] Open
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Lovric J, Mano M, Zentilin L, Eulalio A, Zacchigna S, Giacca M. Terminal differentiation of cardiac and skeletal myocytes induces permissivity to AAV transduction by relieving inhibition imposed by DNA damage response proteins. Mol Ther 2012; 20:2087-97. [PMID: 22850678 DOI: 10.1038/mt.2012.144] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Gene therapy vectors based on the adeno-associated virus (AAV) are extremely efficient for gene transfer into post-mitotic cells of heart, muscle, brain, and retina. The reason for their exquisite tropism for these cells has long remained elusive. Here, we show that upon terminal differentiation, cardiac and skeletal myocytes downregulate proteins of the DNA damage response (DDR) and that this markedly induces permissivity to AAV transduction. We observed that expression of members of the MRN complex (Mre11, Rad50, Nbs1), which bind the incoming AAV genomes, faded in cardiomyocytes at ~2 weeks after birth, as well as upon myoblast differentiation in vitro; in both cases, withdrawal of the cells from the cell cycle coincided with increased AAV permissivity. Treatment of proliferating cells with short-interfering RNAs (siRNAs) against the MRN proteins, or with microRNA-24, which is normally upregulated upon terminal differentiation and negatively controls the Nbs1 levels, significantly increased permissivity to AAV transduction. Consistently, delivery of these small RNAs to the juvenile liver concomitant with AAV markedly improved in vivo hepatocyte transduction. Collectively, these findings support the conclusion that cellular DDR proteins inhibit AAV transduction and that terminal cell differentiation relieves this restriction.
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Affiliation(s)
- Jasmina Lovric
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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Yu YL, Chou RH, Wu CH, Wang YN, Chang WJ, Tseng YJ, Chang WC, Lai CC, Lee HJ, Huo L, Chen CH, Hung MC. Nuclear EGFR suppresses ribonuclease activity of polynucleotide phosphorylase through DNAPK-mediated phosphorylation at serine 776. J Biol Chem 2012; 287:31015-26. [PMID: 22815474 DOI: 10.1074/jbc.m112.358077] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nuclear existence of epidermal growth factor receptor (EGFR) has been documented for more than two decades. Resistance of cancer to radiotherapy is frequently correlated with elevated EGFR expression, activity, and nuclear translocation. However, the role of nuclear EGFR (nEGFR) in radioresistance of cancers remains elusive. In the current study, we identified a novel nEGFR-associated protein, polynucleotide phosphorylase (PNPase), which possesses 3' to 5' exoribonuclease activity toward c-MYC mRNA. Knockdown of PNPase increased radioresistance. Inactivation or knock-down of EGFR enhanced PNPase-mediated c-MYC mRNA degradation in breast cancer cells, and also increased its radiosensitivity. Interestingly, the association of nEGFR with PNPase and DNA-dependent protein kinase (DNAPK) increased significantly in breast cancer cells after exposure to ionizing radiation (IR). We also demonstrated that DNAPK phosphorylates PNPase at Ser-776, which is critical for its ribonuclease activity. The phospho-mimetic S776D mutant of PNPase impaired its ribonuclease activity whereas the nonphosphorylatable S776A mutant effectively degraded c-MYC mRNA. Here, we uncovered a novel role of nEGFR in radioresistance, and that is, upon ionizing radiation, nEGFR inactivates the ribonuclease activity of PNPase toward c-MYC mRNA through DNAPK-mediated Ser-776 phosphorylation, leading to increase of c-MYC mRNA, which contributes to radioresistance of cancer cells.
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Affiliation(s)
- Yung-Luen Yu
- Graduate Institute of Cancer Biology and Center for Molecular Medicine, China Medical University, Taichung 404, Taiwan.
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Kuo KT, Chou TY, Hsu HS, Chen WL, Wang LS. Prognostic Significance of NBS1 and Snail Expression in Esophageal Squamous Cell Carcinoma. Ann Surg Oncol 2011; 19 Suppl 3:S549-57. [DOI: 10.1245/s10434-011-2043-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Indexed: 11/18/2022]
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Cheng L, Wu Q, Huang Z, Guryanova OA, Huang Q, Shou W, Rich JN, Bao S. L1CAM regulates DNA damage checkpoint response of glioblastoma stem cells through NBS1. EMBO J 2011; 30:800-13. [PMID: 21297581 DOI: 10.1038/emboj.2011.10] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 01/11/2011] [Indexed: 12/21/2022] Open
Abstract
Glioblastomas (GBMs) are highly lethal brain tumours with current therapies limited to palliation due to therapeutic resistance. We previously demonstrated that GBM stem cells (GSCs) display a preferential activation of DNA damage checkpoint and are relatively resistant to radiation. However, the molecular mechanisms underlying the preferential checkpoint response in GSCs remain undefined. Here, we show that L1CAM (CD171) regulates DNA damage checkpoint responses and radiosensitivity of GSCs through nuclear translocation of L1CAM intracellular domain (L1-ICD). Targeting L1CAM by RNA interference attenuated DNA damage checkpoint activation and repair, and sensitized GSCs to radiation. L1CAM regulates expression of NBS1, a critical component of the MRE11-RAD50-NBS1 (MRN) complex that activates ataxia telangiectasia mutated (ATM) kinase and early checkpoint response. Ectopic expression of NBS1 in GSCs rescued the decreased checkpoint activation and radioresistance caused by L1CAM knockdown, demonstrating that L1CAM signals through NBS1 to regulate DNA damage checkpoint responses. Mechanistically, nuclear translocation of L1-ICD mediates NBS1 upregulation via c-Myc. These data demonstrate that L1CAM augments DNA damage checkpoint activation and radioresistance of GSCs through L1-ICD-mediated NBS1 upregulation and the enhanced MRN-ATM-Chk2 signalling.
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Affiliation(s)
- Lin Cheng
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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Wu CY, Lin CT, Wu MZ, Wu KJ. Induction of HSPA4 and HSPA14 by NBS1 overexpression contributes to NBS1-induced in vitro metastatic and transformation activity. J Biomed Sci 2011; 18:1. [PMID: 21208456 PMCID: PMC3022804 DOI: 10.1186/1423-0127-18-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 01/06/2011] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Nijmegen breakage syndrome (NBS) is a chromosomal-instability syndrome associated with cancer predisposition, radiosensitivity, microcephaly, and growth retardation. The NBS gene product, NBS1 (p95) or nibrin, is a part of the MRN complex, a central player associated with double-strand break (DSB) repair. We previously demonstrated that NBS1 overexpression contributes to transformation through the activation of PI 3-kinase/Akt. NBS1 overexpression also induces epithelial-mesenchymal transition through the Snail/MMP2 pathway. METHODS RT-PCR, Western blot analysis, in vitro migration/invasion, soft agar colony formation, and gelatin zymography assays were performed. RESULTS Here we show that heat shock protein family members, A4 and A14, were induced by NBS1 overexpression. siRNA mediated knockdown of HSPA4 or HSPA14 decreased the in vitro migration, invasion, and transformation activity in H1299 cells overexpressing NBS1. However, HSPA4 or HSPA14 induced activity was not mediated through MMP2. NBS1 overexpression induced the expression of heat shock transcription factor 4b (HSF4b), which correlated with the expression of HSPA4 and HSPA14. CONCLUSION These results identify a novel pathway (NBS1-HSF4b-HSPA4/HSPA14 axis) to induce migration, invasion, and transformation, suggesting the activation of multiple signaling events induced by NBS1 overexpression.
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Affiliation(s)
- Chung-Yin Wu
- Institutes of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan
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Luoto KR, Meng AX, Wasylishen AR, Zhao H, Coackley CL, Penn LZ, Bristow RG. Tumor cell kill by c-MYC depletion: role of MYC-regulated genes that control DNA double-strand break repair. Cancer Res 2010; 70:8748-59. [PMID: 20940401 DOI: 10.1158/0008-5472.can-10-0944] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
MYC regulates a myriad of genes controlling cell proliferation, metabolism, differentiation, and apoptosis. MYC also controls the expression of DNA double-strand break (DSB) repair genes and therefore may be a potential target for anticancer therapy to sensitize cancer cells to DNA damage or prevent genetic instability. In this report, we studied whether MYC binds to DSB repair gene promoters and modulates cell survival in response to DNA-damaging agents. Chromatin immunoprecipitation studies showed that MYC associates with several DSB repair gene promoters including Rad51, Rad51B, Rad51C, XRCC2, Rad50, BRCA1, BRCA2, DNA-PKcs, XRCC4, Ku70, and DNA ligase IV. Endogenous MYC protein expression was associated with increased RAD51 and KU70 protein expression of a panel of cancer cell lines of varying histopathology. Induction of MYC in G(0)-G(1) and S-G(2)-M cells resulted in upregulation of Rad51 gene expression. MYC knockdown using small interfering RNA (siRNA) led to decreased RAD51 expression but minimal effects on homologous recombination based on a flow cytometry direct repeat green fluorescent protein assay. siRNA to MYC resulted in tumor cell kill in DU145 and H1299 cell lines in a manner independent of apoptosis. However, MYC-dependent changes in DSB repair protein expression were not sufficient to sensitize cells to mitomycin C or ionizing radiation, two agents selectively toxic to DSB repair-deficient cells. Our results suggest that anti-MYC agents may target cells to prevent genetic instability but would not lead to differential radiosensitization or chemosensitization.
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Affiliation(s)
- Kaisa R Luoto
- Campbell Family Cancer Research Institute, University of Toronto, Ontario Cancer Institute/Princess Margaret Hospital, Toronto, Ontario, Canada
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c-Myc Attenuates The Ability of Doxorubicin to Reduce The Colony Formation Partially Through Regulating Nbs1 in U2OS Cells*. PROG BIOCHEM BIOPHYS 2010. [DOI: 10.3724/sp.j.1206.2010.00048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Albihn A, Johnsen JI, Henriksson MA. MYC in oncogenesis and as a target for cancer therapies. Adv Cancer Res 2010; 107:163-224. [PMID: 20399964 DOI: 10.1016/s0065-230x(10)07006-5] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
MYC proteins (c-MYC, MYCN, and MYCL) regulate processes involved in many if not all aspects of cell fate. Therefore, it is not surprising that the MYC genes are deregulated in several human neoplasias as a result from genetic and epigenetic alterations. The near "omnipotency" together with the many levels of regulation makes MYC an attractive target for tumor intervention therapy. Here, we summarize some of the current understanding of MYC function and provide an overview of different cancer forms with MYC deregulation. We also describe available treatments and highlight novel approaches in the pursuit for MYC-targeting therapies. These efforts, at different stages of development, constitute a promising platform for novel, more specific treatments with fewer side effects. If successful a MYC-targeting therapy has the potential for tailored treatment of a large number of different tumors.
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Affiliation(s)
- Ami Albihn
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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Hsu DSS, Chang SY, Liu CJ, Tzeng CH, Wu KJ, Kao JY, Yang MH. Identification of increased NBS1 expression as a prognostic marker of squamous cell carcinoma of the oral cavity. Cancer Sci 2010; 101:1029-37. [PMID: 20175780 PMCID: PMC11159783 DOI: 10.1111/j.1349-7006.2009.01471.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2024] Open
Abstract
Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers worldwide; however, accurate molecular markers to predict its prognosis are still limited. We previously demonstrated that overexpression of the DNA double-strand break repair protein NBS1 is a prognostic marker of advanced head and neck squamous cell carcinoma (HNSCC). Therefore, we aimed to investigate the feasibility of using NBS1 as a biomarker in OSCC. In this study, we enrolled 148 OSCC for immunohistochemical (IHC) and clinical analysis. Data from 58 advanced non-oral-cavity HNSCC (NO-HNSCC) cases were also included for comparison due to the biological and clinical discrepancy between OSCC and HNSCC originated from the other sites (e.g. pharynx or larynx). First, we validated the NBS1 IHC results by real-time RT-PCR analysis, and an excellent correlation between the results of these two assays confirmed the reliability and robustness of IHC procedures and interpretation. NBS1 overexpression was an independent prognostic marker in both OSCC and NO-HNSCC cases. In OSCC, the prognostic significance of NBS1 was shown regardless of T stage and lymph node status. Increased NBS1 expression correlated with advanced T stage and recurrence/metastasis. NBS1 overexpression correlated with the phosphorylation levels of Akt and its downstream target mammalian target of rapamycin (mTOR). These results clearly illustrate the expression profile of NBS1 in OSCC and NO-HNSCC, and highlight the role of NBS1 in HNSCC irrespective of the primary sites. It also indicates the practicability of application of NBS1 as a marker in OSCC.
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Guerra L, Albihn A, Tronnersjö S, Yan Q, Guidi R, Stenerlöw B, Sterzenbach T, Josenhans C, Fox JG, Schauer DB, Thelestam M, Larsson LG, Henriksson M, Frisan T. Myc is required for activation of the ATM-dependent checkpoints in response to DNA damage. PLoS One 2010; 5:e8924. [PMID: 20111719 PMCID: PMC2811743 DOI: 10.1371/journal.pone.0008924] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 01/05/2010] [Indexed: 01/20/2023] Open
Abstract
Background The MYC protein controls cellular functions such as differentiation, proliferation, and apoptosis. In response to genotoxic agents, cells overexpressing MYC undergo apoptosis. However, the MYC-regulated effectors acting upstream of the mitochondrial apoptotic pathway are still unknown. Principal Findings In this study, we demonstrate that expression of Myc is required to activate the Ataxia telangiectasia mutated (ATM)-dependent DNA damage checkpoint responses in rat cell lines exposed to ionizing radiation (IR) or the bacterial cytolethal distending toxin (CDT). Phosphorylation of the ATM kinase and its downstream effectors, such as histone H2AX, were impaired in the myc null cell line HO15.19, compared to the myc positive TGR-1 and HOmyc3 cells. Nuclear foci formation of the Nijmegen Breakage Syndrome (Nbs) 1 protein, essential for efficient ATM activation, was also reduced in absence of myc. Knock down of the endogenous levels of MYC by siRNA in the human cell line HCT116 resulted in decreased ATM and CHK2 phosphorylation in response to irradiation. Conversely, cell death induced by UV irradiation, known to activate the ATR-dependent checkpoint, was similar in all the cell lines, independently of the myc status. Conclusion These data demonstrate that MYC contributes to the activation of the ATM-dependent checkpoint responses, leading to cell death in response to specific genotoxic stimuli.
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Affiliation(s)
- Lina Guerra
- Departments of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Ami Albihn
- Departments of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Susanna Tronnersjö
- Departments of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Qinzi Yan
- Departments of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Riccardo Guidi
- Departments of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Bo Stenerlöw
- Division of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Torsten Sterzenbach
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Christine Josenhans
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - James G. Fox
- Department of Biological Engineering, Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - David B. Schauer
- Department of Biological Engineering, Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Monica Thelestam
- Departments of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Lars-Gunnar Larsson
- Departments of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Marie Henriksson
- Departments of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Teresa Frisan
- Departments of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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Chang L, Liu Y, Zhu B, Li Y, Hua H, Wang Y, Zhang J, Jiang Z, Wang Z. High expression of the circadian gene mPer2 diminishes the radiosensitivity of NIH 3T3 cells. Braz J Med Biol Res 2009; 42:882-91. [DOI: 10.1590/s0100-879x2009005000022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 07/22/2009] [Indexed: 01/17/2023] Open
Affiliation(s)
| | | | - B. Zhu
- Sichuan University, China
| | - Y. Li
- Sichuan University, China
| | - H. Hua
- Sichuan University, China
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Chen YC, Teng SC, Wu KJ. Phosphorylation of Telomeric Repeat Binding Factor 1 (TRF1) by Akt Causes Telomere Shortening. Cancer Invest 2009; 27:24-8. [DOI: 10.1080/07357900802027081] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Tsai YP, Yang MH, Huang CH, Chang SY, Chen PM, Liu CJ, Teng SC, Wu KJ. Interaction between HSP60 and β-catenin promotes metastasis. Carcinogenesis 2009; 30:1049-57. [DOI: 10.1093/carcin/bgp087] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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41
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Wu HT, Su YN, Hung CC, Hsieh WS, Wu KJ. Interaction between PHOX2B and CREBBP mediates synergistic activation: Mechanistic implications of PHOX2B mutants. Hum Mutat 2009; 30:655-60. [DOI: 10.1002/humu.20929] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Knight JF, Shepherd CJ, Rizzo S, Brewer D, Jhavar S, Dodson AR, Cooper CS, Eeles R, Falconer A, Kovacs G, Garrett MD, Norman AR, Shipley J, Hudson DL. TEAD1 and c-Cbl are novel prostate basal cell markers that correlate with poor clinical outcome in prostate cancer. Br J Cancer 2008; 99:1849-58. [PMID: 19002168 PMCID: PMC2600693 DOI: 10.1038/sj.bjc.6604774] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 10/16/2008] [Accepted: 10/16/2008] [Indexed: 12/20/2022] Open
Abstract
Prostate cancer is the most frequently diagnosed male cancer, and its clinical outcome is difficult to predict. The disease may involve the inappropriate expression of genes that normally control the proliferation of epithelial cells in the basal layer and their differentiation into luminal cells. Our aim was to identify novel basal cell markers and assess their prognostic and functional significance in prostate cancer. RNA from basal and luminal cells isolated from benign tissue by immunoguided laser-capture microdissection was subjected to expression profiling. We identified 112 and 267 genes defining basal and luminal populations, respectively. The transcription factor TEAD1 and the ubiquitin ligase c-Cbl were identified as novel basal cell markers. Knockdown of either marker using siRNA in prostate cell lines led to decreased cell growth in PC3 and disrupted acinar formation in a 3D culture system of RWPE1. Analyses of prostate cancer tissue microarray staining established that increased protein levels of either marker were associated with decreased patient survival independent of other clinicopathological metrics. These data are consistent with basal features impacting on the development and clinical course of prostate cancers.
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Affiliation(s)
- J F Knight
- Department of Molecular Carcinogenesis, The Bob Champion Prostate Stem Cell Team, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - C J Shepherd
- Department of Molecular Carcinogenesis, The Bob Champion Prostate Stem Cell Team, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - S Rizzo
- Department of Molecular Carcinogenesis, The Bob Champion Prostate Stem Cell Team, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - D Brewer
- Department of Molecular Carcinogenesis, Cell Transformation Team, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - S Jhavar
- Department of Molecular Carcinogenesis, Cell Transformation Team, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
- Translational Cancer Genetics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - A R Dodson
- Department of Pathology and Molecular Genetics, University of Liverpool, Duncan Building, Liverpool, UK
| | - C S Cooper
- Department of Molecular Carcinogenesis, Cell Transformation Team, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - R Eeles
- Translational Cancer Genetics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - A Falconer
- Translational Cancer Genetics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
- Department of Oncology, Charing Cross Hospital, London W6 8RF, UK
| | - G Kovacs
- Ruprecht-Karls-Universitat, Heidelberg Klinikum, Molekular Onkologie, Im Neuenheimer Feld 365, Heidelberg 69120, Germany
| | - M D Garrett
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - A R Norman
- Department of Medical Statistics, Royal Marsden NHS Trust, Sutton, Surrey SM2 5NG, UK
| | - J Shipley
- Department of Molecular Carcinogenesis, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - D L Hudson
- Department of Molecular Carcinogenesis, The Bob Champion Prostate Stem Cell Team, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
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Direct regulation ofHSP60expression by c-MYC induces transformation. FEBS Lett 2008; 582:4083-8. [DOI: 10.1016/j.febslet.2008.11.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 11/05/2008] [Accepted: 11/05/2008] [Indexed: 01/02/2023]
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Gluz O, Wild P, Meiler R, Diallo‐Danebrock R, Ting E, Mohrmann S, Schuett G, Dahl E, Fuchs T, Herr A, Gaumann A, Frick M, Poremba C, Nitz UA, Hartmann A. Nuclear karyopherin α2 expression predicts poor survival in patients with advanced breast cancer irrespective of treatment intensity. Int J Cancer 2008; 123:1433-8. [DOI: 10.1002/ijc.23628] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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45
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The activated Notch1 receptor cooperates with alpha-enolase and MBP-1 in modulating c-myc activity. Mol Cell Biol 2008; 28:4829-42. [PMID: 18490439 DOI: 10.1128/mcb.00175-08] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The Notch signal pathway plays multifaceted roles to promote or suppress tumorigenesis. The Notch1 receptor intracellular domain (N1IC), the activated form of the Notch1 receptor, activates the c-myc proto-oncogene. The complex of N1IC and transcription factor YY1 binds to the human c-myc promoter to enhance c-myc expression in a CBF1-independent manner. Here we demonstrated that N1IC interacted with the c-Myc-regulating proteins alpha-enolase and c-myc promoter binding protein 1 (MBP-1). Both alpha-enolase and MBP-1 suppressed the N1IC-enhanced activity of the c-myc promoter in a CBF1-independent manner. The YY1 response element in front of the P2 c-myc promoter was essential and sufficient for the modulation of c-myc by N1IC and alpha-enolase or MBP-1. Furthermore, N1IC, YY1, and alpha-enolase or MBP-1 but not CBF1 bound to the c-myc promoter through associating with the YY1 response element. Hemin-induced erythroid differentiation was suppressed by N1IC in K562 cells. This suppression was relieved by the expression of alpha-enolase and MBP-1. In addition, both alpha-enolase and MBP-1 suppressed the N1IC-enhanced colony-forming ability through c-myc. These results indicate that the activated Notch1 receptor and alpha-enolase or MBP-1 cooperate in controlling c-myc expression through binding the YY1 response element of the c-myc promoter to regulate tumorigenesis.
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Culjkovic B, Tan K, Orolicki S, Amri A, Meloche S, Borden KLB. The eIF4E RNA regulon promotes the Akt signaling pathway. ACTA ACUST UNITED AC 2008; 181:51-63. [PMID: 18391071 PMCID: PMC2287285 DOI: 10.1083/jcb.200707018] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Eukaryotic initiation factor 4E (eIF4E) promotes cellular proliferation and can rescue cells from apoptotic stimuli such as serum starvation. However, the mechanisms underlying apoptotic rescue are not well understood. In this study, we demonstrate that eIF4E overexpression leads to enhanced survival signaling through Akt and that eIF4E requires Akt1 to rescue serum-deprived fibroblasts. Furthermore, a mutant form of eIF4E (W73A), which is messenger RNA (mRNA) export competent but does not promote translation, rescues cells as readily as wild-type eIF4E. We show that eIF4E mediates Akt activation via up-regulation of Nijmegen breakage syndrome 1 (NBS1), a phosphoinositide-3 kinase–Akt pathway upstream activator. Additionally, eIF4E coordinately up-regulates the expression of downstream effectors of the Akt pathway, thereby amplifying Akt signaling effects. A negative regulator of eIF4E, the promyelocytic leukemia protein (PML), suppresses Akt activation and apoptotic rescue. These PML activities likely arise, at least in part, through its inhibition of eIF4E-mediated NBS1 mRNA export. In summary, eIF4E coordinately regulates gene expression to potentiate Akt activation, an activity required for apoptotic rescue.
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Affiliation(s)
- Biljana Culjkovic
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H4M 1J6, Canada
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Direct regulation of TWIST by HIF-1alpha promotes metastasis. Nat Cell Biol 2008; 10:295-305. [PMID: 18297062 DOI: 10.1038/ncb1691] [Citation(s) in RCA: 1028] [Impact Index Per Article: 64.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Accepted: 01/24/2008] [Indexed: 12/13/2022]
Abstract
Stabilization of the hypoxia-inducible factor-1alpha (HIF-1alpha) transcription complex, caused by intratumoural hypoxia, promotes tumour progression and metastasis, leading to treatment failure and mortality in different types of human cancers. The transcription factor TWIST is a master regulator of gastrulation and mesoderm-specification and was implicated recently as an essential mediator of cancer metastasis. Notably, HIF-1alpha- and TWIST-null mice show similarities in their phenotypes. Here, we have shown that hypoxia or overexpression of HIF-1alpha promotes epithelial-mesenchymal transition (EMT) and metastastic phenotypes. We also found that HIF-1 regulates the expression of TWIST by binding directly to the hypoxia-response element (HRE) in the TWIST proximal promoter. However, siRNA-mediated repression of TWIST in HIF-1alpha-overexpressing or hypoxic cells reversed EMT and metastastic phenotypes. Co-expression of HIF-1alpha, TWIST and Snail in primary tumours of patients with head and neck cancers correlated with metastasis and the worst prognosis. These results provide evidence of a key signalling pathway involving HIF-1alpha and TWIST that promotes metastasis in response to intratumoural hypoxia.
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Chen YC, Chiang HY, Yang MH, Chen PM, Chang SY, Teng SC, Vanhaesebroeck B, Wu KJ. Activation of phosphoinositide 3-kinase by the NBS1 DNA repair protein through a novel activation motif. J Mol Med (Berl) 2008; 86:401-12. [PMID: 18270679 DOI: 10.1007/s00109-008-0302-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 11/06/2007] [Accepted: 01/02/2008] [Indexed: 11/25/2022]
Abstract
Class IA phosphoinositide 3-kinases (PI 3-kinases) are key signaling components downstream of tyrosine kinases and Ras, regulating many different cellular functions and contributing to tumorigenesis. Class IA PI 3-kinases are heterodimers comprised of a p85 regulatory and a p110 catalytic subunit. Nijmegen breakage syndrome (NBS) is a chromosomal instability syndrome associated with cancer predisposition, radiosensitivity, microcephaly, and growth retardation. The NBS gene product p95 (also known as NBS1) is part of the Mre11-Rad50-Nbs1 complex, a central player associated with double-strand break repair. We previously demonstrated that NBS1 overexpression induces transformation through activation of PI 3-kinase/Akt. In this study, we show that NBS1 directly interacts, through a highly conserved C-terminal motif (aa 653-669) of NBS1, with the N-terminal domain (aa 1-108) of the p110alpha catalytic subunit of PI 3-kinase, and stimulates PI 3-kinase activity. Mutations of different regions of the conserved motif abolish the ability of NBS1 to activate PI 3-kinase in vitro and in vivo. Co-expression of NBS1/p110alpha/p-Akt is observed in certain percentage of head and neck cancer patient samples. These results demonstrate that NBS1 can function as an adaptor/activator of p110alpha PI 3-kinase through a novel activation motif, consistent with its possible role in cell transformation and tumorigenesis.
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Affiliation(s)
- Yen-Chung Chen
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, No.155, Li-Nong St., Sec.2, Peitou, Taipei 112, Taiwan
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Smith JA, Wang FX, Zhang H, Wu KJ, Williams KJ, Daniel R. Evidence that the Nijmegen breakage syndrome protein, an early sensor of double-strand DNA breaks (DSB), is involved in HIV-1 post-integration repair by recruiting the ataxia telangiectasia-mutated kinase in a process similar to, but distinct from, cellular DSB repair. Virol J 2008; 5:11. [PMID: 18211700 PMCID: PMC2262065 DOI: 10.1186/1743-422x-5-11] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Accepted: 01/22/2008] [Indexed: 01/30/2023] Open
Abstract
Retroviral transduction involves integrase-dependent linkage of viral and host DNA that leaves an intermediate that requires post-integration repair (PIR). We and others proposed that PIR hijacks the host cell double-strand DNA break (DSB) repair pathways. Nevertheless, the geometry of retroviral DNA integration differs considerably from that of DSB repair and so the precise role of host-cell mechanisms in PIR remains unclear. In the current study, we found that the Nijmegen breakage syndrome 1 protein (NBS1), an early sensor of DSBs, associates with HIV-1 DNA, recruits the ataxia telangiectasia-mutated (ATM) kinase, promotes stable retroviral transduction, mediates efficient integration of viral DNA and blocks integrase-dependent apoptosis that can arise from unrepaired viral-host DNA linkages. Moreover, we demonstrate that the ATM kinase, recruited by NBS1, is itself required for efficient retroviral transduction. Surprisingly, recruitment of the ATR kinase, which in the context of DSB requires both NBS1 and ATM, proceeds independently of these two proteins. A model is proposed emphasizing similarities and differences between PIR and DSB repair. Differences between the pathways may eventually allow strategies to block PIR while still allowing DSB repair.
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Affiliation(s)
- Johanna A Smith
- Division of Infectious Diseases - Center for Human Virology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA.
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50
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Rink L, Slupianek A, Stoklosa T, Nieborowska-Skorska M, Urbanska K, Seferynska I, Reiss K, Skorski T. Enhanced phosphorylation of Nbs1, a member of DNA repair/checkpoint complex Mre11-RAD50-Nbs1, can be targeted to increase the efficacy of imatinib mesylate against BCR/ABL-positive leukemia cells. Blood 2007; 110:651-60. [PMID: 17431132 PMCID: PMC1924483 DOI: 10.1182/blood-2006-08-042630] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Accepted: 01/27/2007] [Indexed: 02/06/2023] Open
Abstract
Nbs1, a member of the Mre11-RAD50-Nbs1 complex, is phosphorylated by ATM, the product of the ataxia-telangiectasia mutated gene and a member of the phosphatidylinositol 3-kinase-related family of serine-threonine kinases, in response to DNA double-strand breaks (DSBs) to regulate DNA damage checkpoints. Here we show that BCR/ABL stimulated Nbs1 expression by induction of c-Myc-dependent transactivation and protection from caspase-dependent degradation. BCR/ABL-related fusion tyrosine kinases (FTKs) such as TEL/JAK2, TEL/PDGFbetaR, TEL/ABL, TEL/TRKC, BCR/FGFR1, and NPM/ALK as well as interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and stem cell factor (SCF) also stimulated Nbs1 expression. Enhanced ATM kinase-dependent phosphorylation of Nbs1 on serine 343 (S343) in response to genotoxic treatment was detected in leukemia cells expressing BCR/ABL and other FTKs in comparison to normal counterparts stimulated with IL-3, GM-CSF, and SCF. Expression of Nbs1-S343A mutant disrupted the intra-S-phase checkpoint, decreased homologous recombinational repair (HRR) activity, down-regulated XIAP expression, and sensitized BCR/ABL-positive cells to cytotoxic drugs. Interestingly, inhibition of Nbs1 phosphorylation by S343A mutant enhanced the antileukemia effect of the combination of imatinib and genotoxic agent.
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Affiliation(s)
- Lori Rink
- Department of Microbiology and Immunology, Temple University, Philadelphia, PA 19140, USA
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