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Chava S, Bugide S, Malvi P, Gupta R. Co-targeting of specific epigenetic regulators in combination with CDC7 potently inhibit melanoma growth. iScience 2022; 25:104752. [PMID: 35942091 PMCID: PMC9356103 DOI: 10.1016/j.isci.2022.104752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/31/2022] [Accepted: 07/08/2022] [Indexed: 12/14/2022] Open
Abstract
Melanoma is a highly aggressive skin cancer that frequently metastasizes, but current therapies only benefit some patients. Here, we demonstrate that the serine/threonine kinase cell division cycle 7 (CDC7) is overexpressed in melanoma, and patients with higher expression have shorter survival. Transcription factor ELK1 regulates CDC7 expression, and CDC7 inhibition promotes cell cycle arrest, senescence, and apoptosis, leading to inhibition of melanoma tumor growth and metastasis. Our chemical genetics screen with epigenetic inhibitors revealed stronger melanoma tumor growth inhibition when XL413 is combined with the EZH2 inhibitor GSK343 or BRPF1/2/3 inhibitor OF1. Mechanistically, XL413 with GSK343 or OF1 synergistically altered the expression of tumor-suppressive genes, leading to higher apoptosis than the single agent alone. Collectively, these results identify CDC7 as a driver of melanoma tumor growth and metastasis that can be targeted alone or in combination with EZH2 or BRPF1/2/3 inhibitors.
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Affiliation(s)
- Suresh Chava
- Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Suresh Bugide
- Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Parmanand Malvi
- Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Romi Gupta
- Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, Birmingham, AL 35233, USA
- O’Neal Comprehensive Cancer Center, The University of Alabama at Birmingham, Birmingham, AL 35233, USA
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Yu K, Ji Y, Liu M, Shen F, Xiong X, Gu L, Lu T, Ye Y, Feng S, He J. High Expression of CKS2 Predicts Adverse Outcomes: A Potential Therapeutic Target for Glioma. Front Immunol 2022; 13:881453. [PMID: 35663965 PMCID: PMC9160311 DOI: 10.3389/fimmu.2022.881453] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/14/2022] [Indexed: 11/13/2022] Open
Abstract
Cyclin-dependent kinase regulatory subunit 2 (CKS2) is a potential prognostic marker and is overexpressed in various cancers. This study analyzed sequencing and clinical data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus, with external validation using the Chinese Glioma Genome Atlas (CGGA) data. CKS2 expression in the normal brain and tumor tissue was compared. cBioPortal and MethSurv were utilized to scrutinize the prognostic value of CKS2 methylation. Gene set enrichment examination and single-sample gene set enrichment analysis were employed to explore the potential biological functions of CKS2. Cell viability, colony formation, and transwell assays were conducted to evaluate the influence of CKS2 on glioma cell proliferation and invasion. Compared with normal brain tissue, the expression of CKS2 was upregulated in glioma samples (p < 0.001). Multivariate data analysis from TCGA and CGGA indicated that increased expression of CKS2 was an independent risk factor for the prognosis of overall survival in glioma patients. CKS2 methylation was negatively associated with CKS2 expression. Patients with CKS2 hypomethylation had worse overall survival compared with patients with CKS2 methylation, as suggested by the analysis of both TCGA and CGGA datasets. The expression level of CKS2 is closely related to tumor immunity, including the correlation of tumor immune cell infiltration, immune score, and co-expression of multiple immune-related genes. In addition, CKS2 is associated with several immune checkpoints and responses to the chemotherapy drug cisplatin. CKS2 knockdown impeded the expansion and aggression of glioma cell lines. The changes in CKS2 expression may provide a novel prognostic biomarker that can be used to improve patient overall survival rates.
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Affiliation(s)
- Kai Yu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yulong Ji
- Key Laboratory of Translational Cancer Research, Jiangxi Cancer Hospital of Nangchang University, Nanchang, China
| | - Min Liu
- Department of Neurosurgery, Poyang County People’s Hospital, Shangrao, China
| | - Fugeng Shen
- Bone Traumatology Department, Shangli County Traditional Chinese Medicine Hospital, Pingxiang, China
| | - Xiaoxing Xiong
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Lijuan Gu
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Tianzhu Lu
- Key Laboratory of Translational Cancer Research, Jiangxi Cancer Hospital of Nangchang University, Nanchang, China
| | - Yingze Ye
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Shi Feng
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jianying He
- Department of Orthopedic, JiangXi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
- *Correspondence: Jianying He,
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RASSF1A inhibits PDGFB-driven malignant phenotypes of nasopharyngeal carcinoma cells in a YAP1-dependent manner. Cell Death Dis 2020; 11:855. [PMID: 33057010 PMCID: PMC7560678 DOI: 10.1038/s41419-020-03054-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/12/2022]
Abstract
Nasopharyngeal carcinoma (NPC) is a highly aggressive tumor characterized by distant metastasis. Deletion or down-regulation of the tumor suppressor protein ras-association domain family protein1 isoform A (RASSF1A) has been confirmed to be a key event in NPC progression; however, little is known about the effects or underlying mechanism of RASSF1A on the malignant phenotype. In the present study, we observed that RASSF1A expression inhibited the malignant phenotypes of NPC cells. Stable silencing of RASSF1A in NPC cell lines induced self-renewal properties and tumorigenicity in vivo/in vitro and the acquisition of an invasive phenotype in vitro. Mechanistically, RASSF1A inactivated Yes-associated Protein 1 (YAP1), a transcriptional coactivator, through actin remodeling, which further contributed to Platelet Derived Growth Factor Subunit B (PDGFB) transcription inhibition. Treatment with ectopic PDGFB partially increased the malignancy of NPC cells with transient knockdown of YAP1. Collectively, these findings suggest that RASSF1A inhibits malignant phenotypes by repressing PDGFB expression in a YAP1-dependent manner. PDGFB may serve as a potential interest of therapeutic regulators in patients with metastatic NPC.
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4
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Yu X, Wang Z, Zeng T. Essential gene expression pattern of head and neck squamous cell carcinoma revealed by tumor-specific expression rule based on single-cell RNA sequencing. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165791. [PMID: 32234410 DOI: 10.1016/j.bbadis.2020.165791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 03/14/2020] [Accepted: 03/25/2020] [Indexed: 01/05/2023]
Abstract
Head and neck squamous cell carcinoma (HNSCC) has been widely reported and considered as one of the most threatening diseases to human health. Derived from complicated tissue subtypes, HNSCC has diverse symptoms and pathogenesis. They make the identification of the core carcinogenic factors of such diseases at the multi-cell level difficult. With the development of single-cell sequencing technologies, the effects of non-malignant cells on traditional bulk sequencing data can be eliminated directly. On the basis of fresh single-cell RNA-seq data, we set up a computational filtering strategy for tumor cell identification in an expression rule manner. This strategy can reveal the accurate expression distinction between tumor cells and adjacent tumor microenvironment, which are all supported by literature reports. Validated by several independent datasets, these rule genes can further group HNSCC patients with significant difference on survival risks. Thus, the establishment of our computational approach may not only provide an efficient tool to identify malignant cells in the tumor ecosystem but also deepen our understanding of tumor heterogeneity and tumorigenesis.
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Affiliation(s)
- Xiangtian Yu
- Clinical Research Center, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
| | - Zhenjia Wang
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, United States
| | - Tao Zeng
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China; Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai 201210, China.
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5
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Tsang CM, Lui VWY, Bruce JP, Pugh TJ, Lo KW. Translational genomics of nasopharyngeal cancer. Semin Cancer Biol 2019; 61:84-100. [PMID: 31521748 DOI: 10.1016/j.semcancer.2019.09.006] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/11/2019] [Accepted: 09/11/2019] [Indexed: 12/26/2022]
Abstract
Nasopharyngeal carcinoma (NPC), also named the Cantonese cancer, is a unique cancer with strong etiological association with infection of the Epstein-Barr virus (EBV). With particularly high prevalence in Southeast Asia, the involvement of EBV and genetic aberrations contributive to NPC tumorigenesis have remained unclear for decades. Recently, genomic analysis of NPC has defined it as a genetically homogeneous cancer, driven largely by NF-κB signaling caused by either somatic aberrations of NF-κB negative regulators or by overexpression of the latent membrane protein 1 (LMP1), an EBV viral oncoprotein. This represents a landmark finding of the NPC genome. Exome and RNA sequencing data from new EBV-positive NPC models also highlight the importance of PI3K pathway aberrations in NPC. We also realize for the first time that NPC mutational burden, mutational signatures, MAPK/PI3K aberrations, and MHC Class I gene aberrations, are prognostic for patient outcome. Together, these multiple genomic discoveries begin to shape the focus of NPC therapy development. Given the challenge of NF-κB targeting in human cancers, more innovative drug discovery approaches should be explored to target the unique atypical NF-κB activation feature of NPC. Our next decade of NPC research should focus on further identification of the -omic landscapes of recurrent and metastatic NPC, development of gene-based precision medicines, as well as large-scale drug screening with the newly developed and well-characterized EBV-positive NPC models. Focused preclinical and clinical investigations on these major directions may identify new and effective targeting strategies to further improve survival of NPC patients.
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Affiliation(s)
- Chi Man Tsang
- Department of Anatomical and cellular Pathology and State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | - Vivian Wai Yan Lui
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | - Jeffrey P Bruce
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Trevor J Pugh
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 1L7, Canada; Ontario Institute for Cancer Research, Toronto, ON, M5G 1L7, Canada
| | - Kwok Wai Lo
- Department of Anatomical and cellular Pathology and State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
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CKS Proteins Promote Checkpoint Recovery by Stimulating Phosphorylation of Treslin. Mol Cell Biol 2017; 37:MCB.00344-17. [PMID: 28739856 DOI: 10.1128/mcb.00344-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/11/2017] [Indexed: 01/01/2023] Open
Abstract
CKS proteins are small (9-kDa) polypeptides that bind to a subset of the cyclin-dependent kinases. The two paralogs expressed in mammals, Cks1 and Cks2, share an overlapping function that is essential for early development. However, both proteins are frequently overexpressed in human malignancy. It has been shown that CKS protein overexpression overrides the replication stress checkpoint, promoting continued origin firing. This finding has led to the proposal that CKS protein-dependent checkpoint override allows premalignant cells to evade oncogene stress barriers, providing a causal link to oncogenesis. Here, we provide mechanistic insight into how overexpression of CKS proteins promotes override of the replication stress checkpoint. We show that CKS proteins greatly enhance the ability of Cdk2 to phosphorylate the key replication initiation protein treslin in vitro Furthermore, stimulation of treslin phosphorylation does not occur by the canonical adapter mechanism demonstrated for other substrates, as cyclin-dependent kinase (CDK) binding-defective mutants are capable of stimulating treslin phosphorylation. This effect is recapitulated in vivo, where silencing of Cks1 and Cks2 decreases treslin phosphorylation, and overexpression of wild-type or CDK binding-defective Cks2 prevents checkpoint-dependent dephosphorylation of treslin. Finally, we provide evidence that the role of CKS protein-dependent checkpoint override involves recovery from checkpoint-mediated arrest of DNA replication.
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7
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Jin Y, Cui D, Ren J, Wang K, Zeng T, Gao L. CACNA2D3 is downregulated in gliomas and functions as a tumor suppressor. Mol Carcinog 2016; 56:945-959. [PMID: 27583705 DOI: 10.1002/mc.22548] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 08/22/2016] [Accepted: 08/29/2016] [Indexed: 01/08/2023]
Abstract
CACNA2D3, an auxiliary member of the alpha-2/delta subunit three family of the voltage-dependent calcium channel complex, plays a critical role in tumor suppression. However, its role in glioma carcinogenesis remains largely unknown. Here, we investigated the putative tumor suppressive role of CACNA2D3 in gliomas. Downregulation of CACNA2D3 was frequently detected in glioma tissues and cells compared with their non-tumorigenic counterparts, and correlated with poor survival. To investigate the underlying mechanism of CACNA2D3 in the development and progression of glioma, we performed CACNA2D3 ectopic expression in glioma cells (U87 and U251) and knockdown of CACNA2D3 in LN229 cells and conducted in vitro and in vivo functional assays. Our findings showed that increased intracellular calcium (Ca2+ ) mediated by overexpression of CACNA2D3 induced mitochondrial-mediated apoptosis, upregulation of NLK (through the Wnt/Ca2+ pathway) and inhibition of the epithelial-to-mesenchymal transition. Ectopic expression of CACNA2D3 inhibited cell proliferation, migration, invasion, and tumor growth in vitro and in vivo, whereas CACNA2D3 depletion inhibited cell viability and invasion. Furthermore, we confirmed that CACNA2D3 increased NLK expression in vitro by immunostaining and found that downregulation of CACNA2D3 in glioma cells and high-grade glioma tissue was accompanied by increased methylation. A reporter assay showed increased luciferase activity in NLK knockdown glioma cells and transcriptional activity of β-cantenin/TCF was remarkably enhanced, which further confirmed that NLK antagonizes Wnt signaling-mediated anchorage-dependent and independent cell proliferation and invasion. This mechanism may contribute to a better understanding of glioma cancer pathogenesis and facilitate the development of new therapeutic strategies for the treatment of this disease. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Yi Jin
- Department of Neurosurgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Daming Cui
- Department of Neurosurgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Jie Ren
- Department of Neurosurgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Ke Wang
- Department of Neurosurgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Tao Zeng
- Department of Neurosurgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Liang Gao
- Department of Neurosurgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
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8
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Bruce JP, Yip K, Bratman SV, Ito E, Liu FF. Nasopharyngeal Cancer: Molecular Landscape. J Clin Oncol 2015; 33:3346-55. [DOI: 10.1200/jco.2015.60.7846] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Nasopharyngeal carcinoma (NPC) is a unique epithelial malignancy arising from the superior aspect of the pharyngeal mucosal space, associated with latent Epstein-Barr virus infection in most cases. The capacity to characterize cancer genomes in unprecedented detail is now providing insights into the genesis and molecular underpinnings of this disease. Herein, we provide an overview of the molecular aberrations that likely drive nasopharyngeal tumor development and progression. The contributions of major Epstein-Barr virus–encoded factors, including proteins, small RNAs, and microRNAs, along with their interactions with pathways regulating cell proliferation and survival are highlighted. We review recent analyses that clearly define the role of genetic and epigenetic variations affecting the human genome in NPC. These findings point to the impact of DNA methylation and histone modifications on gene expression programs that promote this malignancy. The molecular interactions that allow NPC cells to evade immune recognition and elimination, which is crucial for the survival of cells expressing potentially immunogenic viral proteins, are also described. Finally, the potential utility of detecting host and viral factors for the diagnosis and prognosis of NPC is discussed. Altogether, the studies summarized herein have greatly expanded our knowledge of the molecular biology of NPC, yet much remains to be uncovered. Emerging techniques for using and analyzing well-annotated biospecimens from patients with NPC will ultimately lead to a greater level of understanding, and enable improvements in precision therapies and clinical outcomes.
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Affiliation(s)
- Jeff P. Bruce
- Jeff P. Bruce, Kenneth Yip, Scott V. Bratman, Emma Ito, and Fei-Fei Liu, University Health Network; and Scott V. Bratman, Emma Ito, and Fei-Fei Liu, University of Toronto, Toronto, Ontario, Canada
| | - Kenneth Yip
- Jeff P. Bruce, Kenneth Yip, Scott V. Bratman, Emma Ito, and Fei-Fei Liu, University Health Network; and Scott V. Bratman, Emma Ito, and Fei-Fei Liu, University of Toronto, Toronto, Ontario, Canada
| | - Scott V. Bratman
- Jeff P. Bruce, Kenneth Yip, Scott V. Bratman, Emma Ito, and Fei-Fei Liu, University Health Network; and Scott V. Bratman, Emma Ito, and Fei-Fei Liu, University of Toronto, Toronto, Ontario, Canada
| | - Emma Ito
- Jeff P. Bruce, Kenneth Yip, Scott V. Bratman, Emma Ito, and Fei-Fei Liu, University Health Network; and Scott V. Bratman, Emma Ito, and Fei-Fei Liu, University of Toronto, Toronto, Ontario, Canada
| | - Fei-Fei Liu
- Jeff P. Bruce, Kenneth Yip, Scott V. Bratman, Emma Ito, and Fei-Fei Liu, University Health Network; and Scott V. Bratman, Emma Ito, and Fei-Fei Liu, University of Toronto, Toronto, Ontario, Canada
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9
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Lee SW, Lin CY, Tian YF, Sun DP, Lin LC, Chen LT, Hsing CH, Huang CT, Hsu HP, Huang HY, Wu LC, Li CF, Shiue YL. Overexpression of CDC28 protein kinase regulatory subunit 1B confers an independent prognostic factor in nasopharyngeal carcinoma. APMIS 2013; 122:206-14. [PMID: 23879533 DOI: 10.1111/apm.12136] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 05/15/2013] [Indexed: 12/28/2022]
Abstract
Data mining on public domain identified that CDC28 protein kinase regulatory subunit 1B (CKS1B) transcript was highly expressed in nasopharyngeal carcinoma (NPC). The expression of CKS1B protein and its clinicopathological associations in patients with NPC were further evaluated. Immunoexpression of CKS1B was retrospectively assessed in biopsies of 124 consecutive NPC patients without initial distant metastasis and treated with consistent guidelines. The correlations between CKS1B immunoexpression levels and clinicopathological features, as well as patient survivals, were analyzed. High CKS1B expression (49.2%) was correlated with the 7th American Joint Committee on Cancer (AJCC) stage (p = 0.014). In multivariate analyses, high CKS1B expression emerged as an independent prognostic factor for worse disease-specific survival (p < 0.001), metastasis-free survival (p < 0.001), and local recurrence-free survival (p = 0.001). High expression of CKS1B is common and associated with adverse prognostic factors and might confer tumor aggressiveness through dysregulation of the cyclin-dependent protein kinase (intrinsic regulatory activity) during cell cycle progression.
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Affiliation(s)
- Sung-Wei Lee
- Department of Radiation Oncology, Chi-Mei Medical Center, Tainan, Taiwan
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Wong AMG, Kong KL, Chen L, Liu M, Wong AMG, Zhu C, Tsang JWH, Guan XY. Characterization ofCACNA2D3as a putative tumor suppressor gene in the development and progression of nasopharyngeal carcinoma. Int J Cancer 2013; 133:2284-95. [DOI: 10.1002/ijc.28252] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 04/04/2013] [Indexed: 12/31/2022]
Affiliation(s)
| | | | | | | | | | | | | | - Xin-Yuan Guan
- Department of Clinical Oncology; The University of Hong Kong; Hong Kong; China
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Cks1 enhances transcription efficiency at the GAL1 locus by linking the Paf1 complex to the 19S proteasome. EUKARYOTIC CELL 2013; 12:1192-201. [PMID: 23825181 DOI: 10.1128/ec.00151-13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cks1 was originally identified based on genetic interactions with CDC28, the gene that encodes Cdk1 in the budding yeast Saccharomyces cerevisiae. Subsequent work has shown that Cks1 binds Cdc28 and modulates its activity against certain substrates. However, the Cks1/Cdc28 complex also has a role in transcriptional chromatin remodeling not related to kinase activity. In order to elucidate protein networks associated with Cks1 transcriptional functions, proteomic analysis was performed on immunoaffinity-purified Cks1, identifying a physical interaction with the Paf1 complex. Specifically, we found that the Paf1 complex component Rtf1 interacts directly with Cks1 and that this interaction is essential for efficient recruitment of Cks1 to chromatin in the context of GAL1 gene induction. We further found that Cks1 in this capacity serves as an adaptor allowing Rtf1 to recruit 19S proteasome particles, shown to be required for efficient RNA production from some rapidly inducible genes such as GAL1.
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Gourzones C, Busson P, Raab-Traub N. Epstein-Barr Virus and the Pathogenesis of Nasopharyngeal Carcinomas. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013. [DOI: 10.1007/978-1-4614-5947-7_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Therapeutic Induction of Apoptosis in Nasopharyngeal Carcinoma. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013. [DOI: 10.1007/978-1-4614-5947-7_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Lo KW, Chung GTY, To KF. Acquired Genetic and Epigenetic Alterations in Nasopharyngeal Carcinoma. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013. [DOI: 10.1007/978-1-4614-5947-7_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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EBV up-regulates cytochrome c through VDAC1 regulations and decreases the release of cytoplasmic Ca2+ in the NPC cell line. Cell Biol Int 2012; 36:733-8. [PMID: 22497278 DOI: 10.1042/cbi20110368] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
EBV (Epstein-Barr virus) is considered to be a major factor that causes NPC (nasopharyngeal carcinoma), which is one of the sneakiest cancers frequently occurring in Southeast Asia and Southern China. Apoptosis and pro-apoptotic signals have been studied for decades; however, few have extended the prevailing view of EBV to its impact on NPC in perspective of apoptosis. One of the important proteins named VDAC1 (voltage-dependent anion protein 1) on the mitochondrial outer membrane controls the pro-apoptotic signals in mammalian cells. The impact of EBV infection on VDAC1 and related apoptotic signals remains unclear. In order to study the VDAC1's role in EBV-infected NPC cells, we employ siRNA (small interfering RNA) inhibition to analyse the release of Ca2+ and Cyto c (cytochrome c) signals in the cytoplasm, as they are important pro-apoptotic signals. The results show a decrease of Ca2+ release and up-regulation of Cyto c with EBV infection. After siRNA transfection, the dysregulation of Cyto c is neutralized, which is evidence that the level of Cyto c release in virus-infected NPC cells is the as same as that of non-infected NPC cells. This result indicates that EBV infection changes the cytoplasmic level of Cyto c through regulating VDAC1. In summary, this study reports that EBV changes the release of Ca2+ and Cyto c in the cytoplasm of NPC cells, and that Cyto c changes are mediated by VDAC1 regulation.
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Wang Z, Li L, Su X, Gao Z, Srivastava G, Murray PG, Ambinder R, Tao Q. Epigenetic silencing of the 3p22 tumor suppressor DLEC1 by promoter CpG methylation in non-Hodgkin and Hodgkin lymphomas. J Transl Med 2012; 10:209. [PMID: 23050586 PMCID: PMC3540012 DOI: 10.1186/1479-5876-10-209] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Accepted: 10/04/2012] [Indexed: 12/25/2022] Open
Abstract
Background Inactivaion of tumor suppressor genes (TSGs) by promoter CpG methylation frequently occurs in tumorigenesis, even in the early stages, contributing to the initiation and progression of human cancers. Deleted in lung and esophageal cancer 1 (DLEC1), located at the 3p22-21.3 TSG cluster, has been identified frequently silenced by promoter CpG methylation in multiple carcinomas, however, no study has been performed for lymphomas yet. Methods We examined the expression of DLEC1 by semi-quantitative reverse transcription (RT)-PCR, and evaluated the promoter methylation of DLEC1 by methylation-specific PCR (MSP) and bisulfite genomic sequencing (BGS) in common lymphoma cell lines and tumors. Results Here we report that DLEC1 is readily expressed in normal lymphoid tissues including lymph nodes and PBMCs, but reduced or silenced in 70% (16/23) of non-Hodgkin and Hodgkin lymphoma cell lines, including 2/6 diffuse large B-cell (DLBCL), 1/2 peripheral T cell lymphomas, 5/5 Burkitt, 6/7 Hodgkin and 2/3 nasal killer (NK)/T-cell lymphoma cell lines. Promoter CpG methylation was frequently detected in 80% (20/25) of lymphoma cell lines and correlated with DLEC1 downregulation/silencing. Pharmacologic demethylation reversed DLEC1 expression in lymphoma cell lines along with concomitant promoter demethylation. DLEC1 methylation was also frequently detected in 32 out of 58 (55%) different types of lymphoma tissues, but not in normal lymph nodes. Furthermore, DLEC1 was specifically methylated in the sera of 3/13 (23%) Hodgkin lymphoma patients. Conclusions Thus, methylation-mediated silencing of DLEC1 plays an important role in multiple lymphomagenesis, and may serve as a non-invasive tumor marker for lymphoma diagnosis.
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Affiliation(s)
- Zhaohui Wang
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences-CUHK, Shenzhen, China
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Liu Z, Chen J, Luo W, Yang H, Wu A, Zhen Y, Yu X, Wang H, Yao K, Li X, Fang W. Overexpressed DNA-binding protein inhibitor 2 as an unfavorable prognosis factor promotes cell proliferation in nasopharyngeal carcinoma. Acta Biochim Biophys Sin (Shanghai) 2012; 44:503-12. [PMID: 22551584 DOI: 10.1093/abbs/gms030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The aim of the present study was to analyze the expression of DNA-binding protein inhibitor 2 (ID2) in nasopharyngeal carcinoma (NPC) and its correlation with clinicopathological features. It was found that the expression of ID2 was significantly increased in NPC cells when compared with that in NP69 cell line. Similar level of ID2 cytoplasmic expression was observed in NPC when compared with that in non-cancerous nasopharynx tissues. However, the level of ID2 in nucleus was increased in NPC when compared with that in normal nasopharynx tissues. Furthermore, the higher expression level of nuclear ID2 was significantly associated with tumor size (T classification), lymph node metastasis (N classification), and clinical stage. Patients with increased ID2 expression level had poorer overall survival rates than those with low ID2 levels. The inhibition of ID2 expression in NPC cell line SUNE1 by lentiviral-mediated short hairpin RNA could suppress cell proliferation and colony formation, but did not disrupt cell migration. Knocking down the expression of ID2 by RNA interference could down-regulate the expression of Snail, suggesting that ID2-promoted cell growth, partially attributing to the regulation of Snail activity in NPC. Our study demonstrated that over-expression of ID2 protein is an unfavorable prognostic factor which promotes cell proliferation in NPC.
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Affiliation(s)
- Zhen Liu
- Department of Pathology, Basic School of Guangzhou Medical College, Guangzhou 510182, China
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Reeves ME, Baldwin ML, Aragon R, Baldwin S, Chen ST, Li X, Mohan S, Amaar YG. RASSF1C modulates the expression of a stem cell renewal gene, PIWIL1. BMC Res Notes 2012; 5:239. [PMID: 22591718 PMCID: PMC3512503 DOI: 10.1186/1756-0500-5-239] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 04/02/2012] [Indexed: 02/07/2023] Open
Abstract
Background RASSF1A and RASSF1C are two major isoforms encoded by the Ras association domain family 1 (RASSF1) gene through alternative promoter selection and mRNA splicing. RASSF1A is a well established tumor suppressor gene. Unlike RASSF1A, RASSF1C appears to have growth promoting actions in lung cancer. In this article, we report on the identification of novel RASSF1C target genes in non small cell lung cancer (NSCLC). Methods Over-expression and siRNA techniques were used to alter RASSF1C expression in human lung cancer cells, and Affymetrix-microarray study was conducted using NCI-H1299 cells over-expressing RASSF1C to identify RASSF1C target genes. Results The microarray study intriguingly shows that RASSF1C modulates the expression of a number of genes that are involved in cancer development, cell growth and proliferation, cell death, and cell cycle. We have validated the expression of some target genes using qRT-PCR. We demonstrate that RASSF1C over-expression increases, and silencing of RASSF1C decreases, the expression of PIWIL1 gene in NSCLC cells using qRT-PCR, immunostaining, and Western blot analysis. We also show that RASSF1C over-expression induces phosphorylation of ERK1/2 in lung cancer cells, and inhibition of the MEK-ERK1/2 pathway suppresses the expression of PIWIL1 gene expression, suggesting that RASSF1C may exert its activities on some target genes such as PIWIL1 through the activation of the MEK-ERK1/2 pathway. Also, PIWIL1 expression is elevated in lung cancer cell lines compared to normal lung epithelial cells. Conclusions Taken together, our findings provide significant data to propose a model for investigating the role of RASSF1C/PIWIL1 proteins in initiation and progression of lung cancer.
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Affiliation(s)
- Mark E Reeves
- Surgical Oncology Laboratory, Loma Linda VA Medical Center, CA 92357, USA
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Lo KW, Chung GTY, To KF. Deciphering the molecular genetic basis of NPC through molecular, cytogenetic, and epigenetic approaches. Semin Cancer Biol 2012; 22:79-86. [PMID: 22245473 DOI: 10.1016/j.semcancer.2011.12.011] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 12/21/2011] [Accepted: 12/22/2011] [Indexed: 12/12/2022]
Abstract
Nasopharyngeal carcinoma (NPC) is consistently associated with EBV infection and prevalence in southern China and Southeast Asia. In addition to EBV, the development of NPC involves cumulative genetic and epigenetic changes influenced by predisposing genetic factors and environmental carcinogens. Over the past two decades, knowledge of genetic and epigenetic alterations of NPC has rapidly accumulated. Multiple chromosomal abnormalities (e.g. copy number changes on chromosomes 3p, 9p, 11q, 12p, and 14q), gene alterations (e.g. p16 deletion and LTBR amplification), and epigenetic changes (e.g. RASSF1A and TSLC1 methylation) have been identified by various genome-wide approaches, such as allelotyping, CGH, and microarray analysis. In this review, we will discuss the critical genetic events that contribute to the initiation and progression of NPC. Studies on the precancerous lesions and in vitro immortalized nasopharyngeal epithelial cell models provide important evidence for the involvement of genetic alterations and EBV infection in early development of this cancer. A hypothetical model describing the role of EBV latent infection and multiple genetic changes in NPC tumorigenesis is proposed.
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Affiliation(s)
- Kwok-Wai Lo
- Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.
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KONG XIANGHENG, MENG WENJIAN, ZHOU ZONGGUANG, LI YUAN, ZHOU BIN, WANG RONG, ZHAN LAN. Overexpression of activating transcription factor 5 in human rectal cancer. Exp Ther Med 2011; 2:827-831. [PMID: 22977583 PMCID: PMC3440731 DOI: 10.3892/etm.2011.295] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 05/31/2011] [Indexed: 01/03/2023] Open
Abstract
The aim of this study was to investigate the relationship between the expression of activating transcription factor 5 (ATF5) and clinicopathological features in human rectal cancer. Relative quantitative real-time RT-PCR and immunohistochemical staining were used to detect ATF5 mRNA and protein expression in 92 paired samples of rectal cancer and distant normal tissues. Immunohistochemical staining of the matched rectal tissue samples revealed that the positive expression rate of the ATF5 protein in rectal cancer was significantly higher compared to that in the normal tissue. Furthermore, the expression of ATF5 in poorly differentiated cancers was higher compared to that in well to moderately differentiated cancers (P=0.013). However, there was no significant association between ATF5 protein expression and patient age, gender, histological tumor type, cell differentiation, invasive depth, lymph node metastasis or distant metastasis (P>0.05). However, to our surprise, there was no difference in the relative mRNA expression levels of ATF5 between normal tissues and rectal cancers. Our findings indicate that overexpression of ATF5 protein may be an important biomarker of the degree of malignancy, and increased expression may be related to the post-transcriptional regulation of ATF5 in rectal cancer tissues.
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Affiliation(s)
- XIANGHENG KONG
- Institute of Digestive Surgery
- Departments of Gastrointestinal Surgery, and
| | - WENJIAN MENG
- Institute of Digestive Surgery
- Departments of Gastrointestinal Surgery, and
| | - ZONGGUANG ZHOU
- Institute of Digestive Surgery
- Departments of Gastrointestinal Surgery, and
| | - YUAN LI
- Institute of Digestive Surgery
| | | | - RONG WANG
- Pathology, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R.
China
| | - LAN ZHAN
- Institute of Digestive Surgery
- Departments of Gastrointestinal Surgery, and
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Reeves ME, Baldwin SW, Baldwin ML, Chen ST, Moretz JM, Aragon RJ, Li X, Strong DD, Mohan S, Amaar YG. Ras-association domain family 1C protein promotes breast cancer cell migration and attenuates apoptosis. BMC Cancer 2010; 10:562. [PMID: 20955597 PMCID: PMC2965177 DOI: 10.1186/1471-2407-10-562] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Accepted: 10/18/2010] [Indexed: 11/10/2022] Open
Abstract
Background The Ras association domain family 1 (RASSF1) gene is a Ras effector encoding two major mRNA forms, RASSF1A and RASSF1C, derived by alternative promoter selection and alternative mRNA splicing. RASSF1A is a tumor suppressor gene. However, very little is known about the function of RASSF1C both in normal and transformed cells. Methods Gene silencing and over-expression techniques were used to modulate RASSF1C expression in human breast cancer cells. Affymetrix-microarray analysis was performed using T47D cells over-expressing RASSF1C to identify RASSF1C target genes. RT-PCR and western blot techniques were used to validate target gene expression. Cell invasion and apoptosis assays were also performed. Results In this article, we report the effects of altering RASSF1C expression in human breast cancer cells. We found that silencing RASSF1C mRNA in breast cancer cell lines (MDA-MB231 and T47D) caused a small but significant decrease in cell proliferation. Conversely, inducible over-expression of RASSF1C in breast cancer cells (MDA-MB231 and T47D) resulted in a small increase in cell proliferation. We also report on the identification of novel RASSF1C target genes. RASSF1C down-regulates several pro-apoptotic and tumor suppressor genes and up-regulates several growth promoting genes in breast cancer cells. We further show that down-regulation of caspase 3 via overexpression of RASSF1C reduces breast cancer cells' sensitivity to the apoptosis inducing agent, etoposide. Furthermore, we found that RASSF1C over-expression enhances T47D cell invasion/migration in vitro. Conclusion Together, our findings suggest that RASSF1C, unlike RASSF1A, is not a tumor suppressor, but instead may play a role in stimulating metastasis and survival in breast cancer cells.
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Affiliation(s)
- Mark E Reeves
- Surgical Oncology Laboratory, 11201 Benton Street (151), Loma Linda VA Medical Center, California 92350, USA
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Hou D, Guan Y, Liu J, Xiao Z, Ouyang Y, Yu Y, Chen Z. Cloning and characterization of the NPCEDRG gene promoter. Mol Cell Biochem 2010; 346:1-10. [PMID: 20821255 DOI: 10.1007/s11010-010-0584-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 08/27/2010] [Indexed: 11/25/2022]
Abstract
NPCEDRG is a novel tumor suppressive gene that localizes to 3p21.3, a chromosomal region frequently associated with loss of heterozygosity (LOH) in a number of malignancies including nasopharyngeal carcinoma (NPC). Its transcriptional down-expression has been shown in the cell lines and primary tumor tissues of NPC. Reintroduction of NPCEDRG into CNE2, a cell line derived from NPC, was effective to induce cell differentiation, control cell growth, and regulate the cell cycle. Little is known about the transcriptional mechanisms controlling NPCEDRG gene expression. In this article, we describe the NPCEDRG gene structure and the transcriptional expression of NPCEDRG; we found that NPCEDRG was expressed weakly in most of NPC cell lines. Using 5' rapid amplification of complementary DNA ends (5'-RACEs), we found that the NPCEDRG gene has several transcription start sites (TSSs) due to the existence of alternatively spliced variants, and the specific TSS of NPCEDRG was located -25 nucleotides upstream of the translation start site. We amend that Human NPCEDRG CDS containing 516 bp but not the 510 bp reported previously. To characterize the NPCEDRG promoter, transient luciferase and/or EGFP reporter assay were carried out with the constructs including various lengths of the 5' flanking region of the NPCEDRG gene. The results demonstrated that the basal promoter is located at the region from -215 to -8 nucleotides, and the optimal promoter is located at the region from -625 to -8 nucleotides upstream of the translation start site. In silico analysis suggested that the promoter region contained potential binding sites for SP1, c-Myb, AREB6, Nkx2-5, and so on. These results provide important clues to elucidate the regulation of NPCEDRG gene expression and function. Further studies are apparently required for the identification of the transcription factors, essential for NPCEDRG expression, which would lead to better understanding of the molecular mechanism of NPCEDRG expression in nasopharyngeal epithelial cells.
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Affiliation(s)
- Defu Hou
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, 87# Xiangya Road, Changsha, 410008, Hunan, China
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Kuo YS, Tang YB, Lu TY, Wu HC, Lin CT. IGFBP-6 plays a role as an oncosuppressor gene in NPC pathogenesis through regulating EGR-1 expression. J Pathol 2010; 222:299-309. [DOI: 10.1002/path.2735] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Richter AM, Pfeifer GP, Dammann RH. The RASSF proteins in cancer; from epigenetic silencing to functional characterization. Biochim Biophys Acta Rev Cancer 2009; 1796:114-28. [DOI: 10.1016/j.bbcan.2009.03.004] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 03/19/2009] [Accepted: 03/21/2009] [Indexed: 01/22/2023]
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Kreidl E, Oztürk D, Metzner T, Berger W, Grusch M. Activins and follistatins: Emerging roles in liver physiology and cancer. World J Hepatol 2009; 1:17-27. [PMID: 21160961 PMCID: PMC2999257 DOI: 10.4254/wjh.v1.i1.17] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 09/10/2009] [Accepted: 09/17/2009] [Indexed: 02/06/2023] Open
Abstract
Activins are secreted proteins belonging to the TGF-β family of signaling molecules. Activin signals are crucial for differentiation and regulation of cell proliferation and apoptosis in multiple tissues. Signal transduction by activins relies mainly on the Smad pathway, although the importance of crosstalk with additional pathways is increasingly being recognized. Activin signals are kept in balance by antagonists at multiple levels of the signaling cascade. Among these, follistatin and FLRG, two members of the emerging family of follistatin-like proteins, can bind secreted activins with high affinity, thereby blocking their access to cell surface-anchored activin receptors. In the liver, activin A is a major negative regulator of hepatocyte proliferation and can induce apoptosis. The functions of other activins expressed by hepatocytes have yet to be more clearly defined. Deregulated expression of activins and follistatin has been implicated in hepatic diseases including inflammation, fibrosis, liver failure and primary cancer. In particular, increased follistatin levels have been found in the circulation and in the tumor tissue of patients suffering from hepatocellular carcinoma as well as in animal models of liver cancer. It has been argued that up-regulation of follistatin protects neoplastic hepatocytes from activin-mediated growth inhibition and apoptosis. The use of follistatin as biomarker for liver tumor development is impeded, however, due to the presence of elevated follistatin levels already during preceding stages of liver disease. The current article summarizes our evolving understanding of the multi-faceted activities of activins and follistatins in liver physiology and cancer.
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Affiliation(s)
- Emanuel Kreidl
- Emanuel Kreidl, Deniz Öztürk, Thomas Metzner, Walter Berger, Michael Grusch, Institute of Cancer Research, Department of Medicine I, Medical University of Vienna, Borschkegasse 8a, Vienna A-1090, Austria
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Implication of activin E in glucose metabolism: Transcriptional regulation of the inhibin/activin βE subunit gene in the liver. Life Sci 2009; 85:534-40. [DOI: 10.1016/j.lfs.2009.08.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 06/08/2009] [Accepted: 08/11/2009] [Indexed: 11/21/2022]
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Regulation of RASSF1A in nasopharyngeal cells and its response to UV irradiation. Gene 2009; 443:55-63. [DOI: 10.1016/j.gene.2009.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 05/04/2009] [Accepted: 05/12/2009] [Indexed: 11/15/2022]
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Cia5d regulates a new fibroblast-like synoviocyte invasion-associated gene expression signature. Arthritis Res Ther 2008; 10:R92. [PMID: 18706093 PMCID: PMC2575606 DOI: 10.1186/ar2476] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 07/17/2008] [Accepted: 08/15/2008] [Indexed: 11/24/2022] Open
Abstract
Introduction The in vitro invasive properties of rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLSs) have been shown to correlate with disease severity and radiographic damage. We recently determined that FLSs obtained from pristane-induced arthritis (PIA)-susceptible DA rats are also highly invasive in the same in vitro assay through Matrigel. The transfer of alleles derived from the arthritis-resistant F344 strain at the arthritis severity locus Cia5d (RNO10), as in DA.F344(Cia5d) congenics, was enough to significantly and specifically reduce the invasive properties of FLSs. This genetically controlled difference in FLS invasion involves increased production of soluble membrane-type 1 matrix metalloproteinase (MMP) by DA, and is dependent on increased activation of MMP-2. In the present study we aimed to characterize the pattern of gene expression that correlates with differences in invasion in order to identify pathways regulated by the Cia5d locus. Methods Synovial tissues were collected from DA and DA.F344(Cia5d) rats 21 days after the induction of PIA. Tissues were digested and FLSs isolated. After a minimum of four passages, FLSs were plated on Matrigel-covered dishes at similar densities, followed by RNA extraction. Illumina RatRef-12 expression BeadChip arrays were used. Expression data were normalized, followed by t-test, logistic regression, and cluster analysis. Real-time PCR was used to validate the microarray data. Results Out of the 22,523 RefSeq gene probes present in the array, 7,665 genes were expressed by the FLSs. The expression of 66 genes was significantly different between the DA and DA.F344(Cia5d) FLSs (P < 0.01). Nineteen of the 66 differentially expressed genes (28.7%) are involved in the regulation of cell cycle progression or cancer-associated phenotypes, such as invasion and contact inhibition. These included Cxcl10, Vil2 and Nras, three genes that are upregulated in DA and known to regulate MMP-2 expression and activation. Nine of the 66 genes (13.6%) are involved in the regulation of estrogen receptor signaling or transcription. Five candidate genes located within the Cia5d interval were also differentially expressed. Conclusions We have identified a novel FLS invasion associated gene expression signature that is regulated by Cia5d. Many of the genes found to be differentially expressed were previously implicated in cancer cell phenotypes, including invasion. This suggests a parallel in the behavior of arthritis FLSs and cancer cells, and identifies novel pathways and genes for therapeutic intervention and prognostication.
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Abstract
SEMA3B, a member of class 3 semaphorins, is a tumor suppressor. Competition with vascular endothelial growth factor (VEGF)165 explains a portion of the activity, whereas the VEGF-independent mechanism was not elucidated. We employed a microarray and screened for the genes whose expression was increased by SEMA3B in NCI-H1299 cells. Insulin-like growth factor-binding protein-6 (IGFBP-6), a tumor suppressor, showed greatest difference in the expression level. Introduction of IGFBP-6 cDNA reduced colony formation both on the dish surface and in soft agar. Insulin-like growth factor II, which antagonizes IGFBP-6, partly abrogated the effect. Inhibition of IGFBP-6 by small interfering RNA diminished the sub-G0/G1 population that was induced by SEMA3B and abrogated the growth suppressive effect of SEMA3B. We concluded that IGFBP-6 is the effector of tumor suppressor activity of SEMA3B in NCI-H1299 cells. It has been reported that beta-catenin suppresses the expression of IGFBP-6. Introduction of beta-catenin into the cells partly abrogated the growth suppressive effect of SEMA3B. Our result indicates that semaphorin signaling and beta-catenin signaling converge on IGFBP-6 and antithetically affect their functions.
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Cyclin-dependent kinase-associated proteins Cks1 and Cks2 are essential during early embryogenesis and for cell cycle progression in somatic cells. Mol Cell Biol 2008; 28:5698-709. [PMID: 18625720 DOI: 10.1128/mcb.01833-07] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cks proteins associate with cyclin-dependent kinases and have therefore been assumed to play a direct role in cell cycle regulation. Mammals have two paralogs, Cks1 and Cks2, and individually deleting the gene encoding either in the mouse has previously been shown not to impact viability. In this study we show that simultaneously disrupting CKS1 and CKS2 leads to embryonic lethality, with embryos dying at or before the morula stage after only two to four cell division cycles. RNA interference (RNAi)-mediated silencing of CKS genes in mouse embryonic fibroblasts (MEFs) or HeLa cells causes cessation of proliferation. In MEFs CKS silencing leads to cell cycle arrest in G(2), followed by rereplication and polyploidy. This phenotype can be attributed to impaired transcription of the CCNB1, CCNA2, and CDK1 genes, encoding cyclin B1, cyclin A, and Cdk1, respectively. Restoration of cyclin B1 expression rescues the cell cycle arrest phenotype conferred by RNAi-mediated Cks protein depletion. Consistent with a direct role in transcription, Cks2 is recruited to chromatin in general and to the promoter regions and open reading frames of genes requiring Cks function with a cell cycle periodicity that correlates with their transcription.
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Lan Y, Zhang Y, Wang J, Lin C, Ittmann MM, Wang F. Aberrant expression of Cks1 and Cks2 contributes to prostate tumorigenesis by promoting proliferation and inhibiting programmed cell death. Int J Cancer 2008; 123:543-51. [PMID: 18498131 DOI: 10.1002/ijc.23548] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The mammalian Cks family consists of 2 well-conserved small proteins, Cks1 and Cks2. Cks1 has been shown to promote cell-cycle progression by triggering degradation of p27(kip1). The function of Cks2 in somatic mammalian cells is not well understood although it is required for the first metaphase/anaphase transition during the meiosis. Emerging evidence shows that elevated expression of Cks1 and Cks2 is often found in a variety of tumors, and is correlated with poor survival rate of the patients. Here we demonstrated that expression of Cks1 and Cks2 were elevated in prostate tumors of human and animal models, as well as prostatic cancer cell lines. Forced expression of Cks1 and Cks2 in benign prostate tumor epithelial cells promoted cell population growth. Knockdown of Cks1 expression in malignant prostate tumor cells inhibited proliferation, anchorage-independent growth, and migration activities, whereas knockdown of Cks2 expression induced programmed cell death and inhibited the tumorigenicity. Collectively, the data suggest that elevated expression of Cks1 contributes to the tumorigenicity of prostate tumor cells by promoting cell growth and elevated expression of Cks2 protects the cells from apoptosis. Thus, the finding suggests a novel therapeutic strategy for prostatic cancer based on inhibiting Cks1 and Cks2 activity.
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Affiliation(s)
- Yongsheng Lan
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030-3303, USA
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Deli A, Kreidl E, Santifaller S, Trotter B, Seir K, Berger W, Schulte-Hermann R, Rodgarkia-Dara C, Grusch M. Activins and activin antagonists in hepatocellular carcinoma. World J Gastroenterol 2008; 14:1699-709. [PMID: 18350601 PMCID: PMC2695910 DOI: 10.3748/wjg.14.1699] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In many parts of the world hepatocellular carcinoma (HCC) is among the leading causes of cancer-related mortality but the underlying molecular pathology is still insufficiently understood. There is increasing evidence that activins, which are members of the transforming growth factor β (TGFβ) superfamily of growth and differentiation factors, could play important roles in liver carcinogenesis. Activins are disulphide-linked homo- or heterodimers formed from four different β subunits termed βA, βB, βC, and βE, respectively. Activin A, the dimer of two βA subunits, is critically involved in the regulation of cell growth, apoptosis, and tissue architecture in the liver, while the hepatic function of other activins is largely unexplored so far. Negative regulators of activin signals include antagonists in the extracellular space like the binding proteins follistatin and FLRG, and at the cell membrane antagonistic co-receptors like Cripto or BAMBI. Additionally, in the intracellular space inhibitory Smads can modulate and control activin activity. Accumulating data suggest that deregulation of activin signals contributes to pathologic conditions such as chronic inflammation, fibrosis and development of cancer. The current article reviews the alterations in components of the activin signaling pathway that have been observed in HCC and discusses their potential significance for liver tumorigenesis.
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Ahlborn GJ, Nelson GM, Ward WO, Knapp G, Allen JW, Ouyang M, Roop BC, Chen Y, O'Brien T, Kitchin KT, Delker DA. Dose response evaluation of gene expression profiles in the skin of K6/ODC mice exposed to sodium arsenite. Toxicol Appl Pharmacol 2008; 227:400-16. [DOI: 10.1016/j.taap.2007.10.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 10/02/2007] [Accepted: 10/29/2007] [Indexed: 12/13/2022]
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Huang DY, Lin YT, Jan PS, Hwang YC, Liang ST, Peng Y, Huang CYF, Wu HC, Lin CT. Transcription factor SOX-5 enhances nasopharyngeal carcinoma progression by down-regulating SPARC gene expression. J Pathol 2007; 214:445-55. [DOI: 10.1002/path.2299] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Abstract
RASSF1A (Ras association domain family 1 isoform A) is a recently discovered tumor suppressor whose inactivation is implicated in the development of many human cancers. Although it can be inactivated by gene deletion or point mutations, the most common contributor to loss or reduction of RASSF1A function is transcriptional silencing of the gene by inappropriate promoter methylation. This epigenetic mechanism can inactivate numerous tumor suppressors and is now recognized as a major contributor to the development of cancer. RASSF1A lacks apparent enzymatic activity but contains a Ras association (RA) domain and is potentially an effector of the Ras oncoprotein. RASSF1A modulates multiple apoptotic and cell cycle checkpoint pathways. Current evidence supports the hypothesis that it serves as a scaffold for the assembly of multiple tumor suppressor complexes and may relay pro-apoptotic signaling by K-Ras.
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Affiliation(s)
- Howard Donninger
- Molecular Targets Group, Department of Medicine, J. G. Brown Cancer Center, University of Louisville, 119C Baxter Boulevard, 580 S. Preston Street, Louisville, KY 40202, USA
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Wood VHJ, O'Neil JD, Wei W, Stewart SE, Dawson CW, Young LS. Epstein-Barr virus-encoded EBNA1 regulates cellular gene transcription and modulates the STAT1 and TGFbeta signaling pathways. Oncogene 2007; 26:4135-47. [PMID: 17486072 DOI: 10.1038/sj.onc.1210496] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Epstein-Barr virus (EBV)-encoded EBNA1 protein is expressed in all virus-associated tumors where it plays an essential role in the maintenance, replication and transcription of the EBV genome. Transcriptional profiling of EBNA1-expressing carcinoma cells demonstrated that EBNA1 also influences the expression of a range of cellular genes including those involved in translation, transcription and cell signaling. Of particular interest was the ability of EBNA1 to enhance expression of STAT1 and sensitize cells to interferon-induced STAT1 activation with resultant enhancement of major histocompatibility complex expression. A negative effect of EBNA1 on the expression of TGFbeta1-responsive betaig-h3 and PAI-1 genes was confirmed at the protein level in EBV-infected carcinoma cells. This effect resulted from the ability of EBNA1 to repress TGFbeta1-induced transcription via a reduction in the interaction of SMAD2 with SMAD4. More detailed analysis revealed that EBNA1 induces a lower steady-state level of SMAD2 protein as a consequence of increased protein turnover. These data show that EBNA1 can influence cellular gene transcription resulting in effects that may contribute to the development of EBV-associated tumors.
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Affiliation(s)
- V H J Wood
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Edgbaston, Birmingham, UK
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37
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Chiu RWK, Chim SSC, Wong IHN, Wong CSC, Lee WS, To KF, Tong JHM, Yuen RKC, Shum ASW, Chan JKC, Chan LYS, Yuen JWF, Tong YK, Weier JF, Ferlatte C, Leung TN, Lau TK, Lo KW, Lo YMD. Hypermethylation of RASSF1A in human and rhesus placentas. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:941-50. [PMID: 17322379 PMCID: PMC1864885 DOI: 10.2353/ajpath.2007.060641] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The pseudomalignant nature of the placenta prompted us to search for tumor suppressor gene hypermethylation, a phenomenon widely reported in cancer, in the human placenta. Nine tumor suppressor genes were studied. Hypermethylation of the Ras association domain family 1 A (RASSF1A) gene was found in human placentas from all three trimesters of pregnancy but was absent in other fetal tissues. Hypermethylation of Rassf1 was similarly observed in placentas from the rhesus monkey but not the mouse. An inverse relationship between RASSF1A promoter methylation and gene expression was demonstrated by bisulfite sequencing of microdissected placental cells and immunohistochemical staining of placental tissue sections using an anti-RASSF1A antibody. Treatment of choriocarcinoma cell lines, JAR and JEG3, by 5-aza-2'-deoxycytidine and trichostatin A led to reduction in RASSF1A methylation but increased expression. These observations extend the analogy between the primate placenta and malignant tumors to the epigenetic level.
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Affiliation(s)
- Rossa W K Chiu
- Department of Chemical Pathology, The Chinese University of Hong Kong, Shatin, China
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Monaco SE, Angelastro JM, Szabolcs M, Greene LA. The transcription factor ATF5 is widely expressed in carcinomas, and interference with its function selectively kills neoplastic, but not nontransformed, breast cell lines. Int J Cancer 2007; 120:1883-90. [PMID: 17266024 DOI: 10.1002/ijc.22469] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
ATF5, a transcription factor important in differentiation, proliferation and survival, has been found to be highly expressed in neural progenitor cells and in certain tumors including glioblastomas (GBMs), but its expression in other normal and neoplastic tissues has not been extensively investigated. A tissue microarray immunostained for ATF5 showed diffuse nuclear expression (as defined by the presence in greater than 25% of cells) in 63% (117/186) of neoplastic samples, when compared to only 32% (20/62) in nonneoplastic tissues. When analyzed by histologic subtype, a significantly greater proportion of adenocarcinomas, transitional cell carcinomas, squamous cell carcinomas and metastatic carcinomas of various tissue origins had nuclear staining when compared to nonneoplastic tissues. There was no significant difference in ATF5 expression in renal cell carcinomas, lymphomas and seminomas, when compared to nonneoplastic tissues. An expanded series of nonarray breast resection specimens revealed a significantly greater proportion of ATF5 positivity in ductal and lobular carcinomas, when compared to normal breast tissue. Past work found that loss of ATF5 function triggers death of GBM cells, but not of normal activated astrocytes. Here, we observed that loss of ATF5 function caused significant apoptotic death of neoplastic breast cell lines, but not of nonneoplastic breast cell lines. Our data demonstrate elevated ATF5 expression in a wide variety of neoplasms and that interference with ATF5 function selectively triggers death of breast carcinoma cells. Such findings may have potential therapeutic application.
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Affiliation(s)
- Sara E Monaco
- Department of Pathology, Columbia University College of Physicians and Surgeons, New York, NY, USA
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Liu FF, Frappier L, Kim J, O'Sullivan B, Hui A, Bastianutto C. East-West Symposium on nasopharyngeal cancer. Int J Radiat Oncol Biol Phys 2007; 67:703-8. [PMID: 17141974 DOI: 10.1016/j.ijrobp.2006.09.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Accepted: 09/06/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND To achieve greater understanding of the epidemiology, pathogenesis, molecular oncology, diagnostic, and therapeutic aspects of nasopharyngeal cancer (NPC), an international meeting was held in June 2005, Toronto, Canada. RESULTS Further insights were obtained into the role of EBV in NPC development, with its diverse effects ranging from proliferative signals via NF-kB, to immunesuppression, to angiogenic gene regulation. Subsequently, multiple pathways are dysregulated in NPC as revealed by expression array analyses, including apoptosis, integrin, and B-catenin cascades. Advances have been made in the diagnosis and monitoring of NPC, using transoral brushings and plasma levels of EBV transcripts, which may not directly correlate with the number of circulating tumor cells, but is nevertheless informative in predicting and tracking disease response. Many novel therapies have promising results, particularly in the areas of immunotherapies, and the exploration of molecularly targeted approaches such as cetuximab or histone deacetylase inhibitors. CONCLUSIONS The results from large randomized trials and meta-analyses have consistently demonstrated the benefit of concurrent chemotherapy with curative radiation therapy, but at a cost of greater acute and late-tissue toxicities. Further advances are required to achieve an improved understanding on the inter-relationship between environmental and genetic determinants in NPC development, to reduce the global burden of this disease. At the same time, novel therapeutic approaches are necessary to increase curability of NPC, but with reduced long-term toxicities.
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Affiliation(s)
- Fei-Fei Liu
- Department of Radiation Oncology, Princess Margaret Hospital, University Health Network, Toronto, Canada.
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40
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Cho WCS. Nasopharyngeal carcinoma: molecular biomarker discovery and progress. Mol Cancer 2007; 6:1. [PMID: 17199893 PMCID: PMC1774581 DOI: 10.1186/1476-4598-6-1] [Citation(s) in RCA: 176] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Accepted: 01/02/2007] [Indexed: 12/15/2022] Open
Abstract
Nasopharyngeal carcinoma (NPC) is a rare malignancy in most part of the world and it is one of the most confusing, commonly misdiagnosed and poorly understood diseases. The cancer is an Epstein-Barr virus-associated malignancy with a remarkable racial and geographical distribution. It is highly prevalent in southern Asia where the disease occurs at a prevalence about a 100-fold higher compared with other populations not at risk. The etiology of NPC is thought to be associated with a complex interaction of genetic, viral, environmental and dietary factors. Thanks to the advancements in genomics, proteomics and bioinformatics in recent decades, more understanding of the disease etiology, carcinogenesis and progression has been gained. Research into these components may unravel the pathways in NPC development and potentially decipher the molecular characteristics of the malignancy. In the era of molecular medicine, specific treatment to the potential target using technologies such as immunotherapy and RNAi becomes formulating from bench to bedside application and thus makes molecular biomarker discovery more meaningful for NPC management. In this article, the latest molecular biomarker discovery and progress in NPC is reviewed with respect to the diagnosis, monitoring, treatment and prognostication of the disease.
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Affiliation(s)
- William Chi-Shing Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital, Room 1305, 13/F, Block R, 30 Gascoigne Road, Kowloon, Hong Kong SAR, PR China.
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Man C, Rosa J, Lee LTO, Lee VHY, Chow BKC, Lo KW, Doxsey S, Wu ZG, Kwong YL, Jin DY, Cheung ALM, Tsao SW. Latent membrane protein 1 suppresses RASSF1A expression, disrupts microtubule structures and induces chromosomal aberrations in human epithelial cells. Oncogene 2006; 26:3069-80. [PMID: 17099724 DOI: 10.1038/sj.onc.1210106] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epstein-Barr virus (EBV) infection is closely associated with nasopharyngeal carcinoma (NPC) and can be detected in early premalignant lesions of nasopharyngeal epithelium. The latent membrane protein 1 (LMP1) is an oncoprotein encoded by the EBV and is believed to play a role in transforming premalignant nasopharyngeal epithelial cells into cancer cells. RASSF1A is a tumor-suppressor gene commonly inactivated in many types of human cancer including NPC. In this study, we report a novel function of LMP1, in down-regulating RASSF1A expression in human epithelial cells. Downregulation of RASSF1A expression by LMP1 is dependent on the activation of intracellular signaling of NF-kappaB involving the C-terminal activating regions (CTARs) of LMP1. LMP1 expression also suppresses the transcriptional activity of the RASSF1A core promoter. RASSF1A stabilizes microtubules and regulates mitotic events. Aberrant mitotic spindles and chromosome aberrations are reported phenotypes in RASSF1A inactivated cells. In this study, we observed that LMP1 expression in human epithelial cells could induce aberrant mitotic spindles, disorganized interphase microtubules and aneuploidy. LMP1 expression could also suppress microtubule dynamics as exemplified by tracking movements of the growing tips of microtubules in live cells by transfecting EGFP-tagged EB1 into cells. The aberrant mitotic spindles and interphase microtubule organization induced by LMP1 could be rescued by transfecting RASSF1A expression plasmid into cells. Downregulation of RASSF1A expression by LMP1 may facilitate its role in transformation of premalignant nasopharyngeal epithelial cells into cancer cells.
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Affiliation(s)
- C Man
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, People's Republic of China
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42
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Li HM, Man C, Jin Y, Deng W, Yip YL, Feng HC, Cheung YC, Lo KW, Meltzer PS, Wu ZG, Kwong YL, Yuen APW, Tsao SW. Molecular and cytogenetic changes involved in the immortalization of nasopharyngeal epithelial cells by telomerase. Int J Cancer 2006; 119:1567-76. [PMID: 16688717 DOI: 10.1002/ijc.22032] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Nasopharyngeal carcinoma (NPC) is a common disease in Hong Kong and southern provinces of China. EBV infection is believed to play a critical role in the development of NPC. Previous studies on the transformation mechanism of EBV genes were mostly performed in either NPC or nonnasopharyngeal epithelial cells which may not be representative of premalignant nasopharyngeal epithelial cells. Establishment of a representative cell system would greatly facilitate the elucidation of the role of EBV infection in the development of NPC. Using telomerase alone, we were able to establish an immortalized nasopharyngeal epithelial cell line from primary nonmalignant nasopharyngeal biopsies. The telomerase-immortalized nasopharyngeal epithelial cells are largely diploid in karyotype. Interestingly, this newly immortalized nasopharyngeal epithelial cell line, referred as NP460hTert, harbors genetic alterations previously identified in premalignant and malignant nasopharyngeal epithelial cells. These include inactivation of p16 by homozygous deletion of the p16(INK4A) locus and downregulation of RASSF1A expression. The deletion of the p16(INK4A) locus appears to be the most crucial event for the immortalization of nasopharyngeal epithelial cells by telomerase and precedes RASSF1A downregulation. In addition, detailed analysis of the cytogenetic changes by conventional cytogenetics, spectral karyotyping (SKY) and array-based CGH revealed a gain of a 17q21-q25 fragment on 11p15 chromosome in all NP460hTert cells which occurred before deletion of the p16(INK4A) locus. Gain of 17q has been previously reported in NPC. In addition, activation of NF-kappaB was observed in immortalized NP460hTert cells at the later population doublings, and may play a role in the survival of immortalized NP epithelial cells. Id1 which is commonly expressed in various human cancers, including NPC, was also upregulated in the immortalized NP460hTert cells. Thus, the establishment of an immortalized nasopharyngeal epithelial cell line harboring common genetic alterations present in premalignant and cancerous nasopharyngeal epithelial cells may provide a valuable cell system to examine for early events involved in NPC carcinogenesis, particularly in elucidating the role of EBV infection in NPC development.
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Affiliation(s)
- H M Li
- Department of Anatomy, Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Yau WL, Lung HL, Zabarovsky ER, Lerman MI, Sham JST, Chua DTT, Tsao SW, Stanbridge EJ, Lung ML. Functional studies of the chromosome 3p21.3 candidate tumor suppressor geneBLU/ZMYND10 in nasopharyngeal carcinoma. Int J Cancer 2006; 119:2821-6. [PMID: 16929489 DOI: 10.1002/ijc.22232] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Chromosome 3p plays an important role in tumorigenesis in many cancers, including nasopharyngeal carcinoma (NPC). We have previously shown chromosome 3p can suppress tumor growth in vivo by using the monochromosome transfer approach, which indicated the chromosome 3p21.3 region was critical for tumor suppression. BLU/ZMYND10 is one of the candidate tumor suppressor genes mapping in the 3p21.3 critical region and is a candidate TSG for NPC. By quantitative RT-PCR, it is frequently downregulated in NPC cell lines (83%) and NPC biopsies (80%). However, no functional studies have yet verified the functional role of BLU/ZMYND10 as a tumor suppressor gene. In the current study, a gene inactivation test (GIT) utilizing a tetracycline regulation system was used to study the functional role of BLU/ZMYND10. When BLU/ZMYND10 is expressed in the absence of doxycycline, the stable transfectants were able to induce tumor suppression in nude mice. In contrast, downregulation of BLU/ZMYND10 in these tumor suppressive clones by doxycycline treatment restored the tumor formation ability. This study provides the first significant evidence to demonstrate BLU/ZMYND10 can functionally suppress tumor formation in vivo and is, therefore, likely to be one of the candidate tumor suppressor genes involved in NPC.
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Affiliation(s)
- Wing Lung Yau
- Department of Biology and Center for Cancer Research, The Hong Kong University of Science and Technology, Hong Kong (SAR), China
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