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D’Avola A, Kluckova K, Finch AJ, Riches JC. Spotlight on New Therapeutic Opportunities for MYC-Driven Cancers. Onco Targets Ther 2023; 16:371-383. [PMID: 37309471 PMCID: PMC10257908 DOI: 10.2147/ott.s366627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 06/02/2023] [Indexed: 06/14/2023] Open
Abstract
MYC can be considered to be one of the most pressing and important targets for the development of novel anti-cancer therapies. This is due to its frequent dysregulation in tumors and due to the wide-ranging impact this dysregulation has on gene expression and cellular behavior. As a result, there have been numerous attempts to target MYC over the last few decades, both directly and indirectly, with mixed results. This article reviews the biology of MYC in the context of cancers and drug development. It discusses strategies aimed at targeting MYC directly, including those aimed at reducing its expression and blocking its function. In addition, the impact of MYC dysregulation on cellular biology is outlined, and how understanding this can underpin the development of approaches aimed at molecules and pathways regulated by MYC. In particular, the review focuses on the role that MYC plays in the regulation of metabolism, and the therapeutic avenues offered by inhibiting the metabolic pathways that are essential for the survival of MYC-transformed cells.
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Affiliation(s)
- Annalisa D’Avola
- Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - Katarina Kluckova
- Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - Andrew J Finch
- Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - John C Riches
- Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
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2
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Wade JD, Jones JH. The life and work of Robert (Bob) C. Sheppard. J Pept Sci 2021; 28:e3369. [PMID: 34611959 DOI: 10.1002/psc.3369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 11/10/2022]
Abstract
The life and work of Robert Charles Sheppard (1932-2019), Bob Sheppard informally among friends, is outlined. He was a leading pioneer of solid phase peptide synthesis and made the most significant and fundamental European contribution to the art of peptide synthesis since Emil Fischer.
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Affiliation(s)
- John D Wade
- Florey Institute of Neuroscience and Mental Health, Peptide and Protein Chemistry, The University of Melbourne, Parkville, Victoria, Australia.,School of Chemistry, University of Melbourne, Melbourne, Victoria, Australia
| | - John H Jones
- Balliol College, University of Oxford, Oxford, UK
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3
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Toro CA, Zhang L, Cao J, Cai D. Sex differences in Alzheimer's disease: Understanding the molecular impact. Brain Res 2019; 1719:194-207. [PMID: 31129153 DOI: 10.1016/j.brainres.2019.05.031] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 04/10/2019] [Accepted: 05/22/2019] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a common neurodegenerative disorder that presents with cognitive impairment and behavioral disturbance. Approximately 5.5 million people in the United States live with AD, most of whom are over the age of 65 with two-thirds being woman. There have been major advancements over the last decade or so in the understanding of AD neuropathological changes and genetic involvement. However, studies of sex impact in AD have not been adequately integrated into the investigation of disease development and progression. It becomes indispensable to acknowledge in both basic science and clinical research studies the importance of understanding sex-specific differences in AD pathophysiology and pathogenesis, which could guide future effort in the discovery of novel targets for AD. Here, we review the latest and most relevant literature on this topic, highlighting the importance of understanding sex dimorphism from a molecular perspective and its association to clinical trial design and development in AD research field.
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Affiliation(s)
- Carlos A Toro
- National Center for the Medical Consequences of Spinal Cord Injury, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
| | - Larry Zhang
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Jiqing Cao
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
| | - Dongming Cai
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; Neurology Section, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
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4
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Li Y, Zhang D, Yu K, Hu Y, Wu Q, Qian F, Wang Z. CMPD1 inhibited human gastric cancer cell proliferation by inducing apoptosis and G2/M cell cycle arrest. Biol Res 2018; 51:11. [PMID: 29661232 PMCID: PMC5901880 DOI: 10.1186/s40659-018-0159-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 04/10/2018] [Indexed: 01/02/2023] Open
Abstract
Background Gastric cancer occupies the fourth highest morbidity rate of cancers worldwide. Clinical therapies of gastric cancer remain limited because of uncertainty of mechanisms and shortness of effective medicine. Thus, new drug candidates for gastric cancer treatment is urgently needed. Results In this study, CMPD1 as a wildly used MK2 phosphorylation inhibitor was employed to find its impact on gastric cancer cell proliferation, apoptosis and cell cycle using colony formation assay and flow cytometry analysis. Along with its anti-proliferation effect on gastric cancer cell line MKN-45 and SGC7901, CMPD1 also induced massive apoptosis and significant G2/M phase arrest in a time-dependent and dose-dependent manner in MKN-45 cells respectively. Furthermore, Western blot confirmed that the expression of anti-apoptotic proteins Bcl-2 was decreased while BAX, cytochrome c release and cleaved PARP were increased. In addition, oncogene c-Myc was downregulated in response to CMPD1 treatment. Conclusions Our results demonstrated that CMPD1 has anti-tumor effect on human gastric cancer cell line MKN-45 possibly via downregulating oncogene c-Myc expression and CMPD1 could be applied as a potential candidate for treating gastric malignancy. To the best of our knowledge, it is the first report of anti-tumor effect of CMPD-1 on human gastric cancer cells.
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Affiliation(s)
- Yu Li
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, 287 Changhuai Road, Bengbu, 233004, Anhui, People's Republic of China.,Center for Cancer Precision Medicine, Bengbu Medical College, Bengbu, 233003, Anhui, People's Republic of China
| | - Depeng Zhang
- Engineering Research Center of Cell, & Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Kaikai Yu
- Engineering Research Center of Cell, & Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Yudong Hu
- Engineering Research Center of Cell, & Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Qiong Wu
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, 287 Changhuai Road, Bengbu, 233004, Anhui, People's Republic of China.,Center for Cancer Precision Medicine, Bengbu Medical College, Bengbu, 233003, Anhui, People's Republic of China
| | - Feng Qian
- Center for Cancer Precision Medicine, Bengbu Medical College, Bengbu, 233003, Anhui, People's Republic of China. .,Engineering Research Center of Cell, & Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
| | - Zishu Wang
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, 287 Changhuai Road, Bengbu, 233004, Anhui, People's Republic of China. .,Center for Cancer Precision Medicine, Bengbu Medical College, Bengbu, 233003, Anhui, People's Republic of China.
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5
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Nair SA, Nair MB, Jayaprakash PG, Rajalekshmy TN, Nair MK, Pillai MR. Ras and C-Myc Oncoproteins during Tumor Progression in the Uterine Cervix. TUMORI JOURNAL 2018; 84:583-8. [PMID: 9862521 DOI: 10.1177/030089169808400514] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Aims and background Altered oncogenic activity is a feature associated with many malignant and premalignant conditions. Among the many oncogenes, ras and myc are commonly altered in many tumors. This study aims to evaluate the expression of ras and c-myc oncoproteins in a total of 204 cervical tissue samples, including premalignant and malignant lesions as well as apparently normal cervical tissue. Methods and study design Mouse monoclonal antibodies against the three mammalian ras gene products (c-H-ras, c-K-ras, c-N-ras) and the c-myc protein were used to evaluate oncoprotein expression by immunocytochemistry. Results None of the samples analyzed displayed immunoreactivity for H-ras and K-ras. Normal cervical epithelium showed minimal immunoreactivity for N-ras with about 33% of the samples expressing the protein. More conspicuous expression in normal tissue was displayed by c-myc, with about 90% of the samples expressing the protein (mean value of cells positive = 34%). The immunoreactivity for N-ras increased with increasing histological abnormality from low-grade squamous intraepithelial lesions (SIL) to invasive carcinoma. Increased immunoreactivity for N-ras was evident in the basaloid cells of malignant lesions, with the maximum value of 66% found in poorly differentiated squamous cell carcinoma (PDSCC). The percentage of nuclei positive for c-myc also showed a gradual increase from low-grade SIL onwards, the highest positivity being found in PDSCC, where the mean value was 85%. Statistical analysis revealed a good correlation between the expression of N-ras (r = 0.8922, P = 0.001) and c-myc (r = 0.8856, P =0.001) and various histological stages of tumor progression in the cervical epithelium. Conclusions These results therefore suggest that c-myc and N-ras oncoproteins are important during tumor progression in the uterine cervix.
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Affiliation(s)
- S A Nair
- Division of Laboratory Medicine, Regional Cancer Centre, Thiruvananthapuram, Kerala State, India
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Giaretti W. Ploidy and Proliferation Evaluated by Flow Cytometry. An Overview of Techniques and Impact in Oncology. TUMORI JOURNAL 2018; 77:403-19. [PMID: 1838217 DOI: 10.1177/030089169107700508] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Flow cytometric methods for the assessment of nuclear and chromosomal DNA content and of cell proliferation (including methods based on pulse-chase of bromodeoxyuridine and on monoclonal antibodies against nuclear oncoproteins and proliferation-associated antigens) are illustrated by examples and analyzed critically. The impact of most of these techniques for the study of human solid tumors, with exception of nuclear DNA content evaluation, appears still limited. In particular, new studies of cell lines and clinical material from human tumors using new proliferation markers and multiparameter flow cytometry are necessary to solve a considerable number of methodologic and scientific problems.
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Affiliation(s)
- W Giaretti
- Laboratorio di Biofisica e Citometria, Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy
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7
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Gong L, Xia Y, Qian Z, Shi J, Luo J, Song G, Xu J, Ye Z. Overexpression of MYC binding protein promotes invasion and migration in gastric cancer. Oncol Lett 2018; 15:5243-5249. [PMID: 29552163 PMCID: PMC5840499 DOI: 10.3892/ol.2018.7944] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 12/08/2017] [Indexed: 12/28/2022] Open
Abstract
Gastric cancer (GC) is the second leading cause of cancer-associated mortality worldwide. Although the mortality rate of patients with GC has improved, it remains a significant health issue. The MYC proto-oncogene protein serves key roles in cellular proliferation, differentiation, transformation and apoptosis. Previous studies have identified the abnormal expression of MYC-binding protein (MYCBP) during tumorigenesis in multiple types of cancer. Furthermore, evidence demonstrates that the abnormal expression of MYCBP contributes to the invasion and migration of human cancer types, including colon cancer and glioma; however, its influence on GC remains unclear. In the present study, the expression of MYCBP in GC cells and tissues was analyzed by reverse transcription-quantitative polymerase chain reaction. Additionally, GC cell lines were transfected with small interfering RNAs against MYCBP or lymphoid enhancer-binding factor 1 (LEF-1) and assessed by in vitro transwell migration and invasion assays. The results indicated that the expression of MYCBP in GC cells and tissues was markedly increased compared with a normal gastric epithelial cell line and adjacent normal gastric mucosal tissues, respectively. Furthermore, MYCBP downregulation notably inhibited the metastatic capacity of GC cells, and LEF-1 knockdown was found to downregulate the expression of MYCBP. On the basis of the findings of the present study, MYCBP may be a direct target of the β-catenin/LEF-1 pathway via binding LEF-1, and could potentially be used as a biomarker for the diagnosis and prognosis of GC.
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Affiliation(s)
- Lijie Gong
- Department of Gastrointestinal and Pancreatic Surgery, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310000, P.R. China
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310000, P.R. China
| | - Yingjie Xia
- Key Laboratory of Gastroenterology of Zhejiang Province, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310000, P.R. China
| | - Zhenyuan Qian
- Department of Gastrointestinal and Pancreatic Surgery, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310000, P.R. China
- Department of Gastrointestinal and Pancreatic Surgery, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310000, P.R. China
| | - Ji Shi
- Department of Breast and Thyroid Surgery, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang 310000, P.R. China
| | - Jungang Luo
- Department of Gastrointestinal and Pancreatic Surgery, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310000, P.R. China
| | - Guangyuan Song
- Zhejiang University School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310000, P.R. China
| | - Ji Xu
- Department of Gastrointestinal and Pancreatic Surgery, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310000, P.R. China
- Department of Gastrointestinal and Pancreatic Surgery, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310000, P.R. China
| | - Zaiyuan Ye
- Department of Gastrointestinal and Pancreatic Surgery, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310000, P.R. China
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8
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Zhang Q, Hu CM, Yuan Y, He C, Zhao Q, Liu N. Expression of Mina53 and its Significance in Gastric Carcinoma. Int J Biol Markers 2018; 23:83-8. [DOI: 10.1177/172460080802300204] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Aim To study the expression of Mina53 and its relationships with clinicopathological characteristics, antioncogene inactivation and tumor proliferation in human gastric carcinoma, and to explore the role of Mina53 in carcinogenesis and tumor progression. Methods Expression of Mina53 and proliferating cell nuclear antigen (PCNA) was determined in gastric carcinoma (n=79), gastric dysplasia (n=21) and normal gastric tissues (n=20), while p53 was measured in gastric carcinoma tissues by immunohistochemistry. Results Mina53 was negatively expressed in all normal mucosa tissues. Dysplasia specimens showed weakly positive staining for Mina53 in 3 of 21 cases. Elevated expression of Mina53 was observed in 72 (91.1%) of the gastric carcinomas. No significant associations were found between Mina53 and clinicopathological characteristics such as sex, age, histological differentiation, distant metastasis and lymph node metastasis (p>0.05). There was a significant association with depth of invasion (χ2=5.385, p<0.05) and TMN stage (χ2=6.255, p<0.05). In gastric carcinoma, positive staining for p53 was detected in 53 of 79 cases (67.1%), showing a significant association with Mina53 (χ2=5.161, p<0.05). The mean (± SD) PCNA labeling index for gastric carcinoma was 39.47±16.92%. Mina53 expression was positively associated with PCNA level (r=0.756, p<0.01). Conclusion Mina53 was overexpressed in gastric carcinoma and associated with tumor proliferation and antioncogene inactivation. Mina53 could therefore play an important role in the carcinogenesis and progression of gastric carcinoma.
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Affiliation(s)
- Q. Zhang
- Department of Internal Medicine, Clinical Medical College of Yangtze University, Jingzhou, Hubei Province
| | - CM. Hu
- Department of Internal Medicine, Clinical Medical College of Yangtze University, Jingzhou, Hubei Province
| | - Y.S. Yuan
- Department of Internal Medicine, Clinical Medical College of Yangtze University, Jingzhou, Hubei Province
| | - C.H. He
- Department of Gastroenterology, No.1 Hospital Affiliated to Yangtze University, Jingzhou, Hubei Province
| | - Q. Zhao
- Department of Gastroenterology, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province - PR China
| | - N.Z. Liu
- Department of Gastroenterology, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province - PR China
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Wnt9a Is Required for the Aortic Amplification of Nascent Hematopoietic Stem Cells. Cell Rep 2017; 17:1595-1606. [PMID: 27806298 PMCID: PMC6309681 DOI: 10.1016/j.celrep.2016.10.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/07/2016] [Accepted: 10/10/2016] [Indexed: 01/08/2023] Open
Abstract
All mature blood cell types in the adult animal arise from hematopoietic stem and progenitor cells (HSPCs). However, the developmental cues regulating HSPC ontogeny are incompletely understood. In particular, the details surrounding a requirement for Wnt/β-catenin signaling in the development of mature HSPCs are controversial and difficult to consolidate. Using zebrafish, we demonstrate that Wnt signaling is required to direct an amplification of HSPCs in the aorta. Wnt9a is specifically required for this process and cannot be replaced by Wnt9b or Wnt3a. This proliferative event occurs independently of initial HSPC fate specification, and the Wnt9a input is required prior to aorta formation. HSPC arterial amplification occurs prior to seeding of secondary hematopoietic tissues and proceeds, in part, through the cell cycle regulator myca (c-myc). Our results support a general paradigm, in which early signaling events, including Wnt, direct later HSPC developmental processes. Hematopoietic stem and progenitor cells (HSPCs) give rise to all of the blood cells of the adult organism; however, how these cells are derived in vivo is still incompletely understood. Using zebrafish, Grainger et al. find that Wnt9a mediates amplification of HSPCs prior to their migration to secondary hematopoietic sites.
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10
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Kedves AT, Gleim S, Liang X, Bonal DM, Sigoillot F, Harbinski F, Sanghavi S, Benander C, George E, Gokhale PC, Nguyen QD, Kirschmeier PT, Distel RJ, Jenkins J, Goldberg MS, Forrester WC. Recurrent ubiquitin B silencing in gynecological cancers establishes dependence on ubiquitin C. J Clin Invest 2017; 127:4554-4568. [PMID: 29130934 DOI: 10.1172/jci92914] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 10/09/2017] [Indexed: 02/06/2023] Open
Abstract
Transcriptional repression of ubiquitin B (UBB) is a cancer-subtype-specific alteration that occurs in a substantial population of patients with cancers of the female reproductive tract. UBB is 1 of 2 genes encoding for ubiquitin as a polyprotein consisting of multiple copies of ubiquitin monomers. Silencing of UBB reduces cellular UBB levels and results in an exquisite dependence on ubiquitin C (UBC), the second polyubiquitin gene. UBB is repressed in approximately 30% of high-grade serous ovarian cancer (HGSOC) patients and is a recurrent lesion in uterine carcinosarcoma and endometrial carcinoma. We identified ovarian tumor cell lines that retain UBB in a repressed state, used these cell lines to establish orthotopic ovarian tumors, and found that inducible expression of a UBC-targeting shRNA led to tumor regression, and substantial long-term survival benefit. Thus, we describe a recurrent cancer-specific lesion at the level of ubiquitin production. Moreover, these observations reveal the prognostic value of UBB repression and establish UBC as a promising therapeutic target for ovarian cancer patients with recurrent UBB silencing.
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Affiliation(s)
- Alexia T Kedves
- Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Scott Gleim
- Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Xiaoyou Liang
- Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Dennis M Bonal
- Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Frederic Sigoillot
- Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Fred Harbinski
- Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Sneha Sanghavi
- Neurosciences, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Christina Benander
- Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Elizabeth George
- Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | | | | | | | | | - Jeremy Jenkins
- Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | | | - William C Forrester
- Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
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11
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Rezzoug F, Thomas SD, Rouchka EC, Miller DM. Discovery of a Family of Genomic Sequences Which Interact Specifically with the c-MYC Promoter to Regulate c-MYC Expression. PLoS One 2016; 11:e0161588. [PMID: 27551915 PMCID: PMC4995011 DOI: 10.1371/journal.pone.0161588] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/08/2016] [Indexed: 12/14/2022] Open
Abstract
G-quadruplex forming sequences are particularly enriched in the promoter regions of eukaryotic genes, especially of oncogenes. One of the most well studied G-quadruplex forming sequences is located in the nuclease hypersensitive element (NHE) III1 of the c-MYC promoter region. The oncoprotein c-MYC regulates a large array of genes which play important roles in growth regulation and metabolism. It is dysregulated in >70% of human cancers. The silencer NHEIII1 located upstream of the P1 promoter regulates up-to 80% of c-MYC transcription and includes a G-quadruplex structure (Pu27) that is required for promoter inhibition. We have identified, for the first time, a family of seventeen G-quadruplex-forming motifs with >90% identity with Pu27, located on different chromosomes throughout the human genome, some found near or within genes involved in stem cell maintenance or neural cell development. Notably, all members of the Pu27 family interact specifically with NHEIII1 sequence, in vitro. Crosslinking studies demonstrate that Pu27 oligonucleotide binds specifically to the C-rich strand of the NHEIII1 resulting in the G-quadruplex structure stabilization. Pu27 homologous sequences (Pu27-HS) significantly inhibit leukemic cell lines proliferation in culture. Exposure of U937 cells to the Pu27-HS induces cell growth inhibition associated with cell cycle arrest that is most likely due to downregulation of c-MYC expression at the RNA and/or protein levels. Expression of SOX2, another gene containing a Pu27-HS, was affected by Pu27-HS treatment as well. Our data suggest that the oligonucleotides encoding the Pu27 family target complementary DNA sequences in the genome, including those of the c-MYC and SOX2 promoters. This effect is most likely cell type and cell growth condition dependent. The presence of genomic G-quadruplex-forming sequences homologous to Pu27 of c-MYC silencer and the fact that they interact specifically with the parent sequence suggest a common regulatory mechanism for genes whose promoters contain these sequences.
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Affiliation(s)
- Francine Rezzoug
- James Graham Brown Cancer Center, Department of Medicine, University of Louisville, Louisville Kentucky, United States of America
- * E-mail: (FR); (DMM)
| | - Shelia D. Thomas
- James Graham Brown Cancer Center, Department of Medicine, University of Louisville, Louisville Kentucky, United States of America
| | - Eric C. Rouchka
- Department of Computer Engineering and Computer Science, Speed School of Engineering, University of Louisville, Kentucky, United States of America
| | - Donald M. Miller
- James Graham Brown Cancer Center, Department of Medicine, University of Louisville, Louisville Kentucky, United States of America
- * E-mail: (FR); (DMM)
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12
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De Cecco L, Negri T, Brich S, Mauro V, Bozzi F, Dagrada G, Disciglio V, Sanfilippo R, Gronchi A, D'Incalci M, Casali PG, Canevari S, Pierotti MA, Pilotti S. Identification of a gene expression driven progression pathway in myxoid liposarcoma. Oncotarget 2015; 5:5965-77. [PMID: 25115389 PMCID: PMC4171605 DOI: 10.18632/oncotarget.2023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Aim: to investigate the events involved in the progression of myxoid liposarcoma (MLS). Gene expression profiling and immunohistochemical/biochemical analyses were applied to specimens representative of the opposite ends of the MLS spectrum: pure myxoid (ML) and pure round cell (RC) liposarcomas. The analyses revealed the involvement of both coding and non coding RNAs (SNORDs located in DLK1-DIO3 region) and support a model of stepwise progression mainly driven by epigenetic changes involving tumour vascular supply and tumoral cellular component. In this model, a switch in the vascular landscape from a normal to a pro-angiogenic signature and the silencing of DLK1-DIO3 region mark the progression from ML to RC in concert with the acquisition by the latter of the over-expression of YY1/C-MYC/HDAC2, together with over-expression of genes involved in cell proliferation and stemness: MKNK2, MSX1 and TRIM71. Taken together, these findings strongly suggest that to progress from ML to RC liposarcoma the cells have to overcome the epigenetic silencing restriction point in order to reset their new stem-like differentiation signature. Our findings provide a first attempt at identifying the missing links between ML and RC liposarcomas, that may also have broader applications in other clinico-pathological settings characterised by a spectrum of progression.
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Affiliation(s)
- Loris De Cecco
- Functional Genomics and Bioinformatics, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy; These authors contributed equally to this work
| | - Tiziana Negri
- Laboratory of Experimental Molecular Pathology, Department of Diagnostic Pathology and Laboratory, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy; These authors contributed equally to this work
| | - Silvia Brich
- Laboratory of Experimental Molecular Pathology, Department of Diagnostic Pathology and Laboratory, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
| | - Valentina Mauro
- Laboratory of Experimental Molecular Pathology, Department of Diagnostic Pathology and Laboratory, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
| | - Fabio Bozzi
- Laboratory of Experimental Molecular Pathology, Department of Diagnostic Pathology and Laboratory, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
| | - GianPaolo Dagrada
- Laboratory of Experimental Molecular Pathology, Department of Diagnostic Pathology and Laboratory, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
| | - Vittoria Disciglio
- Functional Genomics and Bioinformatics, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
| | - Roberta Sanfilippo
- Adult Mesenchymal Tumor Medical Oncology Unit, Cancer Medicine Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
| | - Alessandro Gronchi
- Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
| | - Maurizio D'Incalci
- Department of Oncology, IRCCS, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Paolo G Casali
- Adult Mesenchymal Tumor Medical Oncology Unit, Cancer Medicine Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
| | - Silvana Canevari
- Functional Genomics and Bioinformatics, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
| | - Marco A Pierotti
- Scientific Directorate, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
| | - Silvana Pilotti
- Laboratory of Experimental Molecular Pathology, Department of Diagnostic Pathology and Laboratory, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan Italy
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13
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Thakur C, Chen F. Current understanding of mdig/MINA in human cancers. Genes Cancer 2015; 6:288-302. [PMID: 26413213 PMCID: PMC4575916 DOI: 10.18632/genesandcancer.73] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 08/05/2015] [Indexed: 12/30/2022] Open
Abstract
Mineral dust-induced gene, mdig has recently been identified and is known to be overexpressed in a majority of human cancers and holds predictive power in the poor prognosis of the disease. Mdig is an environmentally expressed gene that is involved in cell proliferation, neoplastic transformation and immune regulation. With the advancement in deciphering the prognostic role of mdig in human cancers, our understanding on how mdig renders a normal cell to undergo malignant transformation is still very limited. This article reviews the current knowledge of the mdig gene in context to human neoplasias and its relation to the clinico-pathologic factors predicting the outcome of the disease in patients. It also emphasizes on the promising role of mdig that can serve as a potential candidate for biomarker discovery and as a therapeutic target in inflammation and cancers. Considering the recent advances in understanding the underlying mechanisms of tumor formation, more preclinical and clinical research is required to validate the potential of using mdig as a novel biological target of therapeutic and diagnostic value.
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Affiliation(s)
- Chitra Thakur
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, USA
| | - Fei Chen
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, USA
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14
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Lee JEA, Mitchell NC, Zaytseva O, Chahal A, Mendis P, Cartier-Michaud A, Parsons LM, Poortinga G, Levens DL, Hannan RD, Quinn LM. Defective Hfp-dependent transcriptional repression of dMYC is fundamental to tissue overgrowth in Drosophila XPB models. Nat Commun 2015; 6:7404. [PMID: 26074141 DOI: 10.1038/ncomms8404] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 05/06/2015] [Indexed: 02/06/2023] Open
Abstract
Nucleotide excision DNA repair (NER) pathway mutations cause neurodegenerative and progeroid disorders (xeroderma pigmentosum (XP), Cockayne syndrome (CS) and trichothiodystrophy (TTD)), which are inexplicably associated with (XP) or without (CS/TTD) cancer. Moreover, cancer progression occurs in certain patients, but not others, with similar C-terminal mutations in the XPB helicase subunit of transcription and NER factor TFIIH. Mechanisms driving overproliferation and, therefore, cancer associated with XPB mutations are currently unknown. Here using Drosophila models, we provide evidence that C-terminally truncated Hay/XPB alleles enhance overgrowth dependent on reduced abundance of RNA recognition motif protein Hfp/FIR, which transcriptionally represses the MYC oncogene homologue, dMYC. The data demonstrate that dMYC repression and dMYC-dependent overgrowth in the Hfp hypomorph is further impaired in the C-terminal Hay/XPB mutant background. Thus, we predict defective transcriptional repression of MYC by the Hfp orthologue, FIR, might provide one mechanism for cancer progression in XP/CS.
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Affiliation(s)
- Jue Er Amanda Lee
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Melbourne 3010, Australia
| | - Naomi C Mitchell
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Melbourne 3010, Australia
| | - Olga Zaytseva
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Melbourne 3010, Australia
| | - Arjun Chahal
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Melbourne 3010, Australia
| | - Peter Mendis
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Melbourne 3010, Australia
| | | | - Linda M Parsons
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Melbourne 3010, Australia
| | - Gretchen Poortinga
- Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne Victoria 3002, Australia
| | - David L Levens
- Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20892, USA
| | - Ross D Hannan
- 1] Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne Victoria 3002, Australia [2] Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberra Australian Capital Territory 2600, Australia
| | - Leonie M Quinn
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Melbourne 3010, Australia
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15
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Mei Z, Zhang D, Hu B, Wang J, Shen X, Xiao W. FBXO32 Targets c-Myc for Proteasomal Degradation and Inhibits c-Myc Activity. J Biol Chem 2015; 290:16202-14. [PMID: 25944903 DOI: 10.1074/jbc.m115.645978] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Indexed: 11/06/2022] Open
Abstract
FBXO32 (MAFbx/Atrogin-1) is an E3 ubiquitin ligase that is markedly up-regulated in muscle atrophy. Although some data indicate that FBXO32 may play an important role in tumorigenesis, the molecular mechanism of FBXO32 in tumorigenesis has been poorly understood. Here, we present evidence that FBXO32 targets the oncogenic protein c-Myc for ubiquitination and degradation through the proteasome pathway. Phosphorylation of c-Myc at Thr-58 and Ser-62 is dispensable for FBXO32 to induce c-Myc degradation. Mutation of the lysine 326 in c-Myc reduces c-Myc ubiquitination and prevents the c-Myc degradation induced by FBXO32. Furthermore, overexpression of FBXO32 suppresses c-Myc activity and inhibits cell growth, but knockdown of FBXO32 enhances c-Myc activity and promotes cell growth. Finally, we show that FBXO32 is a direct downstream target of c-Myc, highlighting a negative feedback regulation loop between c-Myc and FBXO32. Thus, FBXO32 may function by targeting c-Myc. This work explains the function of FBXO32 and highlights its mechanisms in tumorigenesis.
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Affiliation(s)
- Zhichao Mei
- From the Key Laboratory of Aquatic Biodiversity and Conservation and
| | - Dawei Zhang
- From the Key Laboratory of Aquatic Biodiversity and Conservation and
| | - Bo Hu
- From the Key Laboratory of Aquatic Biodiversity and Conservation and
| | - Jing Wang
- From the Key Laboratory of Aquatic Biodiversity and Conservation and
| | - Xian Shen
- the First Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Wuhan Xiao
- From the Key Laboratory of Aquatic Biodiversity and Conservation and the State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China and
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16
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Diolaiti D, McFerrin L, Carroll PA, Eisenman RN. Functional interactions among members of the MAX and MLX transcriptional network during oncogenesis. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1849:484-500. [PMID: 24857747 PMCID: PMC4241192 DOI: 10.1016/j.bbagrm.2014.05.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Revised: 04/23/2014] [Accepted: 05/14/2014] [Indexed: 01/27/2023]
Abstract
The transcription factor MYC and its related family members MYCN and MYCL have been implicated in the etiology of a wide spectrum of human cancers. Compared to other oncoproteins, such as RAS or SRC, MYC is unique because its protein coding region is rarely mutated. Instead, MYC's oncogenic properties are unleashed by regulatory mutations leading to unconstrained high levels of expression. Under both normal and pathological conditions MYC regulates multiple aspects of cellular physiology including proliferation, differentiation, apoptosis, growth and metabolism by controlling the expression of thousands of genes. How a single transcription factor exerts such broad effects remains a fascinating puzzle. Notably, MYC is part of a network of bHLHLZ proteins centered on the MYC heterodimeric partner MAX and its counterpart, the MAX-like protein MLX. This network includes MXD1-4, MNT, MGA, MONDOA and MONDOB proteins. With some exceptions, MXD proteins have been functionally linked to cell cycle arrest and differentiation, while MONDO proteins control cellular metabolism. Although the temporal expression patterns of many of these proteins can differ markedly they are frequently expressed simultaneously in the same cellular context, and potentially bind to the same, or similar DNA consensus sequence. Here we review the activities and interactions among these proteins and propose that the broad spectrum of phenotypes elicited by MYC deregulation is intimately connected to the functions and regulation of the other network members. Furthermore, we provide a meta-analysis of TCGA data suggesting that the coordinate regulation of the network is important in MYC driven tumorigenesis. This article is part of a Special Issue entitled: Myc proteins in cell biology and pathology.
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Affiliation(s)
- Daniel Diolaiti
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, USA
| | - Lisa McFerrin
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, USA
| | - Patrick A Carroll
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, USA
| | - Robert N Eisenman
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, USA.
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17
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Paula ACC, Martins TMM, Zonari A, Frade SPPJ, Angelo PC, Gomes DA, Goes AM. Human adipose tissue-derived stem cells cultured in xeno-free culture condition enhance c-MYC expression increasing proliferation but bypassing spontaneous cell transformation. Stem Cell Res Ther 2015; 6:76. [PMID: 25889298 PMCID: PMC4455683 DOI: 10.1186/s13287-015-0030-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/24/2015] [Accepted: 03/02/2015] [Indexed: 12/13/2022] Open
Abstract
Introduction Human adipose tissue-derived stem cells (hASCs) are attractive cells for therapeutic applications and are currently being evaluated in multiple clinical trials. Prior to their clinical application, hASCs must be expanded ex vivo to obtain the required number of cells for transplantation. Fetal bovine serum is the supplement most widely used for cell culture, but it has disadvantages and it is not safe for cell therapy due to the risks of pathogen transmission and immune reaction. Furthermore, the cell expansion poses a risk of accumulating genetic abnormalities that could lead to malignant cell transformation. In this study, our aim was to evaluate the proliferation pattern as well as the resistance to spontaneous transformation of hASCs during expansion in a xeno-free culture condition. Methods hASCs were expanded in Dulbecco’s modified Eagle’s medium supplemented with pooled allogeneic human serum or fetal bovine serum to enable a side-by-side comparison. Cell viability and differentiation capacity toward the mesenchymal lineages were assessed, along with immunophenotype. Ki-67 expression and the proliferation kinetics were investigated. The expression of the transcription factors c-FOS and c-MYC was examined with Western blot, and MYC, CDKN2A, ERBB2 and TERT gene expression was assessed with quantitative PCR. Senescence was evaluated by β-gal staining. Karyotype analysis was performed and tumorigenesis assay in vivo was also evaluated. Results The hASCs expanded in medium with pooled allogeneic human serum did not show remarkable differences in morphology, viability, differentiation capacity or immunophenotype. The main difference observed was a significantly higher proliferative effect on hASCs cultured in pooled allogeneic human serum. There was no significant difference in C-FOS expression; however, C-MYC protein expression was enhanced in pooled allogeneic human serum cultures compared to fetal bovine serum cultures. No difference was observed in MYC and TERT mRNA levels. Moreover, the hASCs presented normal karyotype undergoing senescence, and did not form in vivo tumors, eliminating the possibility that spontaneous immortalization of hASCs had occurred with pooled allogeneic human serum. Conclusions This complete characterization of hASCs cultivated in pooled allogeneic human serum, a suitable xeno-free approach, shows that pooled allogeneic human serum provides a high proliferation rate, which can be attributed for the first time to C-MYC protein expression, and showed cell stability for safe clinical applications in compliance with good manufacturing practice.
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Affiliation(s)
- Ana C C Paula
- Laboratory of Cellular and Molecular Immunology, Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-910, Brazil.
| | - Thaís M M Martins
- Laboratory of Cellular and Molecular Immunology, Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-910, Brazil.
| | - Alessandra Zonari
- Laboratory of Cellular and Molecular Immunology, Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-910, Brazil.
| | - Soraia P P J Frade
- Instituto Hermes Pardini, Av. das Nações, 2448, Vespasiano, Minas Gerais, 33200-000, Brazil.
| | - Patrícia C Angelo
- Instituto Hermes Pardini, Av. das Nações, 2448, Vespasiano, Minas Gerais, 33200-000, Brazil.
| | - Dawidson A Gomes
- Laboratory of Cellular and Molecular Immunology, Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-910, Brazil.
| | - Alfredo M Goes
- Laboratory of Cellular and Molecular Immunology, Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-910, Brazil.
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18
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The role of T cell receptor signaling thresholds in guiding T cell fate decisions. Curr Opin Immunol 2015; 33:43-8. [PMID: 25660212 DOI: 10.1016/j.coi.2015.01.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/15/2015] [Accepted: 01/19/2015] [Indexed: 11/21/2022]
Abstract
Canonical T cell receptor signal transduction has been extensively studied and dissected in cell lines and primary lymphocytes. However, a static depiction of this signaling cascade fails to capture the complex and dynamic process by which individual T cells discriminate TCR:peptide-MHC affinity, then integrate signals over time to drive discrete cellular behaviors such as thymic selection, proliferation, and cytokine production. Recent technological advances have made it possible to study complex lymphocyte behavior on a single cell level and are revealing how T cells interpret information about affinity and abundance of antigen in order to make life-and-death cell fate decisions individually and collectively.
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19
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Ding Y, Su S, Tang W, Zhang X, Chen S, Zhu G, Liang J, Wei W, Guo Y, Liu L, Chen YG, Wu W. Enrichment of the β-catenin-TCF complex at the S and G2 phases ensures cell survival and cell cycle progression. J Cell Sci 2014; 127:4833-45. [PMID: 25236602 DOI: 10.1242/jcs.146977] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Wnt-β-catenin (β-catenin is also known as CTNNB1 in human) signaling through the β-catenin-TCF complex plays crucial roles in tissue homeostasis. Wnt-stimulated β-catenin-TCF complex accumulation in the nucleus regulates cell survival, proliferation and differentiation through the transcription of target genes. Compared with their levels in G1, activation of the receptor LRP6 and cytosolic β-catenin are both upregulated in G2 cells. However, accumulation of the Wnt pathway negative regulator AXIN2 also occurs in this phase. Therefore, it is unclear whether Wnt signaling is active in G2 phase cells. Here, we established a bimolecular fluorescence complementation (BiFC) biosensor system for the direct visualization of the β-catenin-TCF interaction in living cells. Using the BiFC biosensor and co-immunoprecipitation experiments, we demonstrate that levels of the nucleus-localized β-catenin-TCF complex increase during the S and G2 phases, and declines in the next G1 phase. Accordingly, a subset of Wnt target genes is transcribed by the β-catenin-TCF complex during both the S and G2 phases. By contrast, transient inhibition of this complex disturbs both cell survival and G2/M progression. Our results suggest that in S and G2 phase cells, Wnt-β-catenin signaling is highly active and functions to ensure cell survival and cell cycle progression.
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Affiliation(s)
- Yajie Ding
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shang Su
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Weixin Tang
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaolei Zhang
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shengyao Chen
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guixin Zhu
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Juan Liang
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wensheng Wei
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Ye Guo
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Tsinghua-Peking Center for Life Sciences, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Lei Liu
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Tsinghua-Peking Center for Life Sciences, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Ye-Guang Chen
- The State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Wu
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
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20
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Impact of MYC in regulation of tumor cell metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:563-9. [PMID: 25038584 DOI: 10.1016/j.bbagrm.2014.07.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/03/2014] [Accepted: 07/09/2014] [Indexed: 02/06/2023]
Abstract
The MYC proto-oncoproteins including c-MYC, MYCN and MYCL exert their functions as heterodimers with MAX, which in turn binds to E-box sequences at target promoters to regulate gene expression. It has been shown that MYC binds to 10-15% of all promoter regions and regulates genes involved in a wide variety of cellular functions. In normal cells the expression of MYC is tightly controlled whereas it is deregulated in the majority of human tumors. MYC contributes to malignant transformation by promoting multiple processes including uncontrolled cell proliferation, cell growth and genomic instability. Importantly, MYC promotes growth by activating genes involved in ribosomal and mitochondrial biogenesis, glucose and glutamine metabolism as well as lipid synthesis. Hence, MYC is contributing to the metabolic reprogramming essential for cancer cells to adapt to the tumor microenvironment. Here we give an overview of the role of MYC in regulation of metabolic pathways in tumor cells. This article is part of a Special Issue entitled: MYC proteins in cell biology and pathology.
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21
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The transcriptional repression activity of STAF65γ is facilitated by promoter tethering and nuclear import of class IIa histone deacetylases. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:579-91. [DOI: 10.1016/j.bbagrm.2014.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/28/2014] [Accepted: 05/13/2014] [Indexed: 12/31/2022]
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22
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Bretones G, Delgado MD, León J. Myc and cell cycle control. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:506-16. [PMID: 24704206 DOI: 10.1016/j.bbagrm.2014.03.013] [Citation(s) in RCA: 483] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 03/18/2014] [Accepted: 03/23/2014] [Indexed: 12/12/2022]
Abstract
Soon after the discovery of the Myc gene (c-Myc), it became clear that Myc expression levels tightly correlate to cell proliferation. The entry in cell cycle of quiescent cells upon Myc enforced expression has been described in many models. Also, the downregulation or inactivation of Myc results in the impairment of cell cycle progression. Given the frequent deregulation of Myc oncogene in human cancer it is important to dissect out the mechanisms underlying the role of Myc on cell cycle control. Several parallel mechanisms account for Myc-mediated stimulation of the cell cycle. First, most of the critical positive cell cycle regulators are encoded by genes induced by Myc. These Myc target genes include Cdks, cyclins and E2F transcription factors. Apart from its direct effects on the transcription, Myc is able to hyperactivate cyclin/Cdk complexes through the induction of Cdk activating kinase (CAK) and Cdc25 phosphatases. Moreover, Myc antagonizes the activity of cell cycle inhibitors as p21 and p27 through different mechanisms. Thus, Myc is able to block p21 transcription or to induce Skp2, a protein involved in p27 degradation. Finally, Myc induces DNA replication by binding to replication origins and by upregulating genes encoding proteins required for replication initiation. Myc also regulates genes involved in the mitotic control. A promising approach to treat tumors with deregulated Myc is the synthetic lethality based on the inhibition of Cdks. Thus, the knowledge of the Myc-dependent cell cycle regulatory mechanisms will help to discover new therapeutic approaches directed against malignancies with deregulated Myc. This article is part of a Special Issue entitled: Myc proteins in cell biology and pathology.
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Affiliation(s)
- Gabriel Bretones
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria-SODERCAN and Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
| | - M Dolores Delgado
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria-SODERCAN and Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
| | - Javier León
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria-SODERCAN and Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain.
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23
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Chen D, Kon N, Zhong J, Zhang P, Yu L, Gu W. Differential effects on ARF stability by normal versus oncogenic levels of c-Myc expression. Mol Cell 2013; 51:46-56. [PMID: 23747016 DOI: 10.1016/j.molcel.2013.05.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 01/18/2013] [Accepted: 05/02/2013] [Indexed: 12/20/2022]
Abstract
ARF suppresses aberrant cell growth upon c-Myc overexpression by activating p53 responses. Nevertheless, the precise mechanism by which ARF specifically restrains the oncogenic potential of c-Myc without affecting its normal physiological function is not well understood. Here, we show that low levels of c-Myc expression stimulate cell proliferation, whereas high levels inhibit by activating the ARF/p53 response. Although the mRNA levels of ARF are induced in both scenarios, the accumulation of ARF protein occurs only when ULF-mediated degradation of ARF is inhibited by c-Myc overexpression. Moreover, the levels of ARF are reduced through ULF-mediated ubiquitination upon DNA damage. Blocking ARF degradation by c-Myc overexpression dramatically stimulates the apoptotic responses. Our study reveals that ARF stability control is crucial for differentiating normal (low) versus oncogenic (high) levels of c-Myc expression and suggests that differential effects on ULF- mediated ARF ubiquitination by c-Myc levels act as a barrier in oncogene-induced stress responses.
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Affiliation(s)
- Delin Chen
- Institute for Cancer Genetics and Department of Pathology and Cell Biology, Herbert Irving Comprehensive Cancer Center, College of Physicians & Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA
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24
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Cattoretti G. MYC expression and distribution in normal mature lymphoid cells. J Pathol 2013; 229:430-40. [PMID: 23165652 DOI: 10.1002/path.4141] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 09/29/2012] [Accepted: 10/13/2012] [Indexed: 11/10/2022]
Abstract
The distribution of the product of the proto-oncogene MYC in lymphoid tissue has not been established in three decades, due to a combination of factors including low abundance, short half-life, and antibody sensitivity and specificity. We sought to validate antibodies in order to define the expression and distribution of MYC in mature normal lymphoid cells by multiparametric immunophenotyping. Having validated two antibodies for flow cytometry and for immunohistochemistry, we analysed normal tonsil tissue. MYC is expressed predominantly in B cells, some of which are interfollicular large, activated, and cycling CD30+, IRF4+, AID± blasts. Follicular mantle, isotype-switched memory B cells and FcRH4/IRTA1+ B cells express MYC in a wide range of levels and are small non-proliferating CDKN1B/p27-positive or -negative resting B lymphocytes. Germinal centre founder cells, CD30+ BCL6± AID± germinal centre blasts, and a population of GC cells in the apical light zone express MYC. MYC is expressed in all phases of the cell cycle in activated and mature B cells, but rarely in other lymphoid types and only partially fulfils the predictions derived from extractive and ex vivo experiments of the past 30 years.
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Affiliation(s)
- Giorgio Cattoretti
- Department of Pathology, University of Milano-Bicocca and San Gerardo Hospital, Via Pergolesi 33, Monza, Italy.
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25
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Nie Z, Hu G, Wei G, Cui K, Yamane A, Resch W, Wang R, Green DR, Tessarollo L, Casellas R, Zhao K, Levens D. c-Myc is a universal amplifier of expressed genes in lymphocytes and embryonic stem cells. Cell 2012; 151:68-79. [PMID: 23021216 PMCID: PMC3471363 DOI: 10.1016/j.cell.2012.08.033] [Citation(s) in RCA: 800] [Impact Index Per Article: 66.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 06/17/2012] [Accepted: 08/08/2012] [Indexed: 01/19/2023]
Abstract
The c-Myc HLH-bZIP protein has been implicated in physiological or pathological growth, proliferation, apoptosis, metabolism, and differentiation at the cellular, tissue, or organismal levels via regulation of numerous target genes. No principle yet unifies Myc action due partly to an incomplete inventory and functional accounting of Myc's targets. To observe Myc target expression and function in a system where Myc is temporally and physiologically regulated, the transcriptomes and the genome-wide distributions of Myc, RNA polymerase II, and chromatin modifications were compared during lymphocyte activation and in ES cells as well. A remarkably simple rule emerged from this quantitative analysis: Myc is not an on-off specifier of gene activity, but is a nonlinear amplifier of expression, acting universally at active genes, except for immediate early genes that are strongly induced before Myc. This rule of Myc action explains the vast majority of Myc biology observed in literature.
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Affiliation(s)
- Zuqin Nie
- Laboratory of Pathology, NCI, Bethesda, MD, 20892
| | - Gangqing Hu
- Systems Biology Center, NHLBI, Bethesda, MD, 20892
| | - Gang Wei
- Systems Biology Center, NHLBI, Bethesda, MD, 20892
| | - Kairong Cui
- Systems Biology Center, NHLBI, Bethesda, MD, 20892
| | - Arito Yamane
- Genomics and Immunity Section, NIAMS, Bethesda, MD, 20892
| | - Wolfgang Resch
- Genomics and Immunity Section, NIAMS, Bethesda, MD, 20892
| | - Ruoning Wang
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105, USA
| | - Douglas R. Green
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105, USA
| | | | | | - Keji Zhao
- Systems Biology Center, NHLBI, Bethesda, MD, 20892
| | - David Levens
- Laboratory of Pathology, NCI, Bethesda, MD, 20892
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Kopecky B, Fritzsch B. The myc road to hearing restoration. Cells 2012; 1:667-98. [PMID: 24710525 PMCID: PMC3901154 DOI: 10.3390/cells1040667] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/12/2012] [Accepted: 09/14/2012] [Indexed: 01/01/2023] Open
Abstract
Current treatments for hearing loss, the most common neurosensory disorder, do not restore perfect hearing. Regeneration of lost organ of Corti hair cells through forced cell cycle re-entry of supporting cells or through manipulation of stem cells, both avenues towards a permanent cure, require a more complete understanding of normal inner ear development, specifically the balance of proliferation and differentiation required to form and to maintain hair cells. Direct successful alterations to the cell cycle result in cell death whereas regulation of upstream genes is insufficient to permanently alter cell cycle dynamics. The Myc gene family is uniquely situated to synergize upstream pathways into downstream cell cycle control. There are three Mycs that are embedded within the Myc/Max/Mad network to regulate proliferation. The function of the two ear expressed Mycs, N-Myc and L-Myc were unknown less than two years ago and their therapeutic potentials remain speculative. In this review, we discuss the roles the Mycs play in the body and what led us to choose them to be our candidate gene for inner ear therapies. We will summarize the recently published work describing the early and late effects of N-Myc and L-Myc on hair cell formation and maintenance. Lastly, we detail the translational significance of our findings and what future work must be performed to make the ultimate hearing aid: the regeneration of the organ of Corti.
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Affiliation(s)
- Benjamin Kopecky
- Department of Biology, 143 Biology Building, University of Iowa, Iowa City, IA 52242, USA.
| | - Bernd Fritzsch
- Department of Biology, 143 Biology Building, University of Iowa, Iowa City, IA 52242, USA.
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Abstract
Neuroblastoma is a pediatric tumor of the sympathetic nervous system. Amplification and overexpression of the MYCN proto-oncogene occurs in approximately 20% of neuroblastomas and is associated with advanced stage disease, rapid tumor progression, and poor prognosis. MYCN encodes the transcriptional regulator N-myc, which has been shown to both up- and downregulate many target genes involved in cell cycle, DNA damage, differentiation, and apoptosis in neuroblastoma. During the last years, it has become clear that N-myc also modulates the expression of several classes of noncoding RNAs, in particular microRNAs. MicroRNAs are the most widely studied noncoding RNA molecules in neuroblastoma. They function as negative regulators of gene expression at the posttranscriptional level in diverse cellular processes. Aberrant regulation of miRNA expression has been implicated in the pathogenesis of neuroblastoma. While the N-myc protein is established as an important regulator of several miRNAs involved in neuroblastoma tumorigenesis, tumor suppressor miRNAs have also been documented to repress MYCN expression and inhibit cell proliferation of MYCN-amplified neuroblastoma cells. It is now becoming increasingly evident that N-myc also regulates the expression of long noncoding RNAs such as T-UCRs and ncRAN. This review summarizes the current knowledge about the interplay between N-myc and noncoding RNAs in neuroblastoma and how this contributes to neuroblastoma tumorigenesis.
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Affiliation(s)
- Jochen Buechner
- Department of Pediatrics, University Hospital of North Norway, Tromsø, Norway
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Ebhardt HA, Sabidó E, Hüttenhain R, Collins B, Aebersold R. Range of protein detection by selected/multiple reaction monitoring mass spectrometry in an unfractionated human cell culture lysate. Proteomics 2012; 12:1185-93. [PMID: 22577020 DOI: 10.1002/pmic.201100543] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Selected or multiple reaction monitoring is a targeted mass spectrometry method (S/MRM-MS), in which many peptides are simultaneously and consistently analyzed during a single liquid chromatography-mass spectrometry (LC-S/MRM-MS) measurement. These capabilities make S/MRM-MS an attractive method to monitor a consistent set of proteins over various experimental conditions. To increase throughput for S/MRM-MS it is advantageous to use scheduled methods and unfractionated protein extracts. Here, we established the practically measurable dynamic range of proteins reliably detectable and quantifiable in an unfractionated protein extract from a human cell line using LC-S/MRM-MS. Initially, we analyzed S/MRM transition peak groups in terms of interfering signals and compared S/MRM transition peak groups to MS1-triggered MS2 spectra using dot-product analysis. Finally, using unfractionated protein extract from human cell lysate, we quantified the upper boundary of copies per cell to be 35 million copies per cell, while 7500 copies per cell represents a lower boundary using a single 35 min linear gradient LC-S/MRM-MS measurement on a current, standard commercial instrument.
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Affiliation(s)
- H Alexander Ebhardt
- Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule (ETH) Zürich, Zürich, Switzerland
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29
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Bmi-1, c-myc, and Snail expression in primary breast cancers and their metastases--elevated Bmi-1 expression in late breast cancer relapses. Virchows Arch 2011; 459:31-9. [PMID: 21638011 DOI: 10.1007/s00428-011-1096-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 05/13/2011] [Accepted: 05/22/2011] [Indexed: 12/31/2022]
Abstract
Breast cancer is known for its propensity to recur decades after treatment. The biology behind the phenomenon of tumor dormancy is still poorly understood. Bmi-1, c-myc, and Snail are transcription factors that have prognostic roles in several malignancies. In order to reveal whether any of these markers has impact on late relapses, we used immunohistochemistry to study the expression of Bmi-1, c-myc, Snail, and estrogen receptor in 73 primary breast cancers and in their metastatic relapses detected within 2 years, or 5 or 10 years after primary surgery. The expression of Bmi-1 was higher in the metastases than in their corresponding primary tumors in both early and late relapses. The highest expression of Bmi-1 was seen in the very late relapsing tumors (first tumor relapse after 10 years). Previously, Bmi-1 has been reported to function as a marker of tumor stem cells in breast cancer. Our results indicate that metastases, when compared to primary tumors, arise from tumor cells that have retained stem cell properties. We also analyzed the relationship between the expression of these markers and clinical parameters. A significant association between the expression of Bmi-1 and estrogen receptor was found. Nuclear expression of c-myc in primary tumors correlated with an increased risk for axillary lymph node metastasis.
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30
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Vasilevsky NA, Ruby CE, Hurlin PJ, Weinberg AD. OX40 engagement stabilizes Mxd4 and Mnt protein levels in antigen-stimulated T cells leading to an increase in cell survival. Eur J Immunol 2011; 41:1024-34. [PMID: 21400495 DOI: 10.1002/eji.201040449] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 11/30/2010] [Accepted: 01/11/2011] [Indexed: 12/28/2022]
Abstract
OX40 engagement on activated T cells leads to increased proliferation, expansion and survival of Ag-specific T cells. Direct ex vivo examination of Ag-stimulated murine T cells show that the Myc antagonists, Mxd4 and Mnt, are transiently upregulated and translocated to the nucleus following OX40 engagement and may be involved in suppressing cell death. Both Mxd4 and Mnt are upregulated following OX40 stimulation through increased protein stability and we identify a critical phosphorylation site in Mxd4 that controls Mxd4 stability. The upregulation of Mxd4 and Mnt contributes to OX40-mediated T-cell survival because siRNA knockdown of Mxd4 and Mnt led to increased cell death. We hypothesize the upregulation of c-Myc following OX40 engagement drives T-cell proliferation and that upregulation of Mxd4 and Mnt suppresses Myc-dependent cell death. Thus, Mxd4 and Mnt upregulation following OX40 engagement most likely increases T-cell survival.
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Affiliation(s)
- Nicole A Vasilevsky
- Earle A. Chiles Research Institute, Providence Portland Medical Center, Portland, OR 97213-2933, USA
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31
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Lai RYJ, Ljubicic V, D'souza D, Hood DA. Effect of chronic contractile activity on mRNA stability in skeletal muscle. Am J Physiol Cell Physiol 2010; 299:C155-63. [PMID: 20375275 DOI: 10.1152/ajpcell.00523.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Repeated bouts of exercise promote the biogenesis of mitochondria by multiple steps in the gene expression patterning. The role of mRNA stability in controlling the expression of mitochondrial proteins is relatively unexplored. To induce mitochondrial biogenesis, we chronically stimulated (10 Hz; 3 or 6 h/day) rat muscle for 7 days. Chronic contractile activity (CCA) increased the protein expression of PGC-1alpha, c-myc, and mitochondrial transcription factor A (Tfam) by 1.6-, 1.7- and 2.0-fold, respectively. To determine mRNA stability, we incubated total RNA with cytosolic extracts using an in vitro cell-free system. We found that the intrinsic mRNA half-lives (t(1/2)) were variable within control muscle. Peroxisome proliferator-activated receptor-gamma, coactivator-1alpha (PGC-1alpha) and Tfam mRNAs decayed more rapidly (t(1/2) = 22.7 and 31.4 min) than c-myc mRNA (t(1/2) = 99.7 min). Furthermore, CCA resulted in a differential response in degradation kinetics. After CCA, PGC-1alpha and Tfam mRNA half-lives decreased by 48% and 44%, respectively, whereas c-myc mRNA half-life was unchanged. CCA induced an elevation of both the cytosolic RNA-stabilizing human antigen R (HuR) and destabilizing AUF1 (total) by 2.4- and 1.8-fold, respectively. Increases in the p37(AUF1), p40(AUF1), and p45(AUF1) isoforms were most evident. Thus these data indicate that CCA results in accelerated turnover rates of mRNAs encoding important mitochondrial biogenesis regulators in skeletal muscle. This adaptation is likely beneficial in permitting more rapid phenotypic plasticity in response to subsequent contractile activity.
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Affiliation(s)
- Ruanne Y J Lai
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
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32
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Chen R, Plunkett W. Strategy to induce apoptosis and circumvent resistance in chronic lymphocytic leukaemia. Best Pract Res Clin Haematol 2010; 23:155-66. [DOI: 10.1016/j.beha.2010.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Brooks TA, Hurley LH. The role of supercoiling in transcriptional control of MYC and its importance in molecular therapeutics. Nat Rev Cancer 2009; 9:849-61. [PMID: 19907434 DOI: 10.1038/nrc2733] [Citation(s) in RCA: 228] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
MYC is deregulated in most tumour types, but an effective means to selectively target its aberrant expression is not yet available. Supercoiling that is induced by transcription has been demonstrated to have dynamic effects on DNA in the MYC promoter element: it converts duplex DNA to non-duplex DNA structures, even at considerable distances from the transcriptional start site. These non-duplex DNA structures, which control both turning on and off of transcription and the rate of transcription firing, are amenable to small-molecule targeting. This dynamic system provides a unique opportunity for the treatment of tumours in which MYC is an important oncogene.
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Affiliation(s)
- Tracy A Brooks
- College of Pharmacy, University of Arizona, Tucson, Arizona 85721, USA
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34
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Rohan JNP, Weigel NL. 1Alpha,25-dihydroxyvitamin D3 reduces c-Myc expression, inhibiting proliferation and causing G1 accumulation in C4-2 prostate cancer cells. Endocrinology 2009; 150:2046-54. [PMID: 19164469 PMCID: PMC2671895 DOI: 10.1210/en.2008-1395] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
There is an inverse correlation between exposure to sunlight (the major source of vitamin D) and the risk for prostate cancer, the most common noncutaneous cancer and second most common cause of death from cancer in American men. The active metabolite of vitamin D, 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] acting through the vitamin D receptor decreases prostate cancer cell growth and invasiveness. The precise mechanisms by which 1,25(OH)(2)D(3) inhibits growth in prostate cancer have not been fully elucidated. Treatment with 1,25(OH)(2)D(3) causes an accumulation in the G(0)/G(1) phase of the cell cycle in several prostate cancer cell lines. One potential target known to regulate the G(0)/G(1) to S phase transition is c-Myc, a transcription factor whose overexpression is associated with a number of cancers including prostate cancer. We find that 1,25(OH)(2)D(3) reduces c-Myc expression in multiple prostate epithelial cell lines, including C4-2 cells, an androgen-independent prostate cancer cell line. Reducing c-Myc expression to the levels observed after 1,25(OH)(2)D(3) treatment resulted in a comparable decrease in proliferation and G(1) accumulation demonstrating that down-regulation of c-Myc is a major component in the growth-inhibitory actions of 1,25(OH)2D(3). Treatment with 1,25(OH)(2)D(3) resulted in a 50% decrease in c-Myc mRNA but a much more extensive reduction in c-Myc protein. Treatment with 1,25(OH)(2)D(3) decreased c-Myc stability by increasing the proportion of c-Myc phosphorylated on T58, a glycogen synthase kinase-3beta site that serves as a signal for ubiquitin-mediated proteolysis. Thus, 1,25(OH)(2)D(3) reduces both c-Myc mRNA levels and c-Myc protein stability to inhibit growth of prostate cancer cells.
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Affiliation(s)
- JoyAnn N Phillips Rohan
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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35
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Chakraborty AA, Tansey WP. Inference of cell cycle-dependent proteolysis by laser scanning cytometry. Exp Cell Res 2009; 315:1772-8. [PMID: 19331831 DOI: 10.1016/j.yexcr.2009.01.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 01/15/2009] [Accepted: 01/16/2009] [Indexed: 11/29/2022]
Abstract
Mechanisms that couple protein turnover to cell cycle progression are critical for coordinating the events of cell duplication and division. Despite the importance of cell cycle-regulated proteolysis, however, technologies to measure this phenomenon are limited, and typically involve monitoring cells that are released back into the cell cycle after synchronization. We describe here the use of laser scanning cytometry (LSC), a technical merger between fluorescence microscopy and flow cytometry, to determine cell cycle-dependent changes in protein stability in unperturbed, asynchronous, cultures of mammalian cells. In this method, the ability of the LSC to accurately measure whole cell fluorescence is employed, together with RNA fluorescence in situ hybridization and immunofluorescence, to relate abundance of a particular RNA and protein in a cell to its point at the cell cycle. Parallel monitoring of RNA and protein levels is used, together with protein synthesis inhibitors, to reveal cell cycle-specific changes in protein turnover. We demonstrate the viability of this method by analyzing the proteolysis of two prominent human oncoproteins, Myc and Cyclin E, and argue that this LSC-based approach offers several practical advantages over traditional cell synchronization methods.
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36
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Daniel JM, Junttila MR, Pouyet L, Karnezis A, Shchors K, Bui DA, Brown-Swigart L, Johnson L, Evan GI. Distinct thresholds govern Myc's biological output in vivo. Cancer Cell 2008; 14:447-57. [PMID: 19061836 PMCID: PMC2723751 DOI: 10.1016/j.ccr.2008.10.018] [Citation(s) in RCA: 349] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2008] [Revised: 10/07/2008] [Accepted: 10/31/2008] [Indexed: 12/25/2022]
Abstract
Deregulated Myc triggers a variety of intrinsic tumor suppressor programs that serve to restrain Myc's oncogenic potential. Since Myc activity is also required for normal cell proliferation, activation of intrinsic tumor suppression must be triggered only when Myc signaling is oncogenic. However, how cells discriminate between normal and oncogenic Myc is unknown. Here we show that distinct threshold levels of Myc govern its output in vivo: low levels of deregulated Myc are competent to drive ectopic proliferation of somatic cells and oncogenesis, but activation of the apoptotic and ARF/p53 intrinsic tumor surveillance pathways requires Myc overexpression. The requirement to keep activated oncogenes at a low level to avoid engaging tumor suppression is likely an important selective pressure governing the early stages of tumor microevolution.
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Affiliation(s)
| | - Melissa R. Junttila
- University of California San Francisco, Dept. of Pathology
- Enrique Cepero, PhD Fellow of the Damon Runyon Cancer Research Foundation
| | - Laurent Pouyet
- University of California San Francisco, Dept. of Pathology
| | - Anthony Karnezis
- University of California San Francisco, Helen Diller Family Comprehensive Cancer Center
| | - Ksenya Shchors
- University of California San Francisco, Dept. of Pathology
| | - Duyen A. Bui
- University of California San Francisco, Dept. of Pathology
| | | | | | - Gerard. I. Evan
- University of California San Francisco, Dept. of Pathology
- University of California San Francisco, Helen Diller Family Comprehensive Cancer Center
- To whom correspondence should be addressed: (+1 415 514 9760)
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37
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miR-17 and miR-20a temper an E2F1-induced G1 checkpoint to regulate cell cycle progression. Oncogene 2008; 28:140-5. [PMID: 18836483 DOI: 10.1038/onc.2008.372] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The stringent regulation of cell cycle progression helps to maintain genetic stability in cells. MicroRNAs (miRNAs) are critical regulators of gene expression in diverse cellular pathways, including developmental patterning, hematopoietic differentiation and antiviral defense. Here, we show that two c-Myc-regulated miRNAs, miR-17 and miR-20a, govern the transition through G1 in normal diploid human cells. Inhibition of these miRNAs leads to a G1 checkpoint due to an accumulation of DNA double-strand breaks, resulting from premature temporal accumulation of the E2F1 transcription factor. Surprisingly, gross changes in E2F1 levels were not required to initiate the DNA damage response and checkpoint, as these responses could occur with a less than twofold change in E2F1 protein levels. Instead, our findings indicate that the precise timing of E2F1 expression dictates S-phase entry and that accurate timing of E2F1 accumulation requires converging signals from the Rb/E2F pathway and the c-Myc-regulated miR-17 and miR-20a miRNAs to circumvent a G1 checkpoint arising from the untimely accumulation of E2F1. These data provide a mechanistic view of miRNA-based regulation of E2F1 in the context of the emerging model that miRNAs coordinate the timing of cell cycle progression.
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38
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Koo EWY, Edelman ER. Cellular effects of antisensec-mycoligodeoxynucleotides are delivery dependent. Drug Deliv 2008; 3:149-54. [DOI: 10.3109/10717549609029444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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39
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40
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Barré B, Perkins ND. A cell cycle regulatory network controlling NF-kappaB subunit activity and function. EMBO J 2007; 26:4841-55. [PMID: 17962807 PMCID: PMC2099464 DOI: 10.1038/sj.emboj.7601899] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 09/27/2007] [Indexed: 11/09/2022] Open
Abstract
Aberrantly active NF-kappaB complexes can contribute to tumorigenesis by regulating genes that promote the growth and survival of cancer cells. We have investigated NF-kappaB during the cell cycle and find that its ability to regulate the G1-phase expression of key proto-oncogenes is subject to regulation by the integrated activity of IkappaB kinase (IKK)alpha, IKKbeta, Akt and Chk1. The coordinated binding of NF-kappaB subunits to the Cyclin D1, c-Myc and Skp2 promoters is dynamic with distinct changes in promoter occupancy and RelA(p65) phosphorylation occurring through G1, S and G2 phases, concomitant with a switch from coactivator to corepressor recruitment. Akt activity is required for IKK-dependent phosphorylation of NF-kappaB subunits in G1 and G2 phases, where Chk1 is inactive. However, in S-phase, Akt is inactivated, while Chk1 phosphorylates RelA and associates with IKKalpha, inhibiting the processing of the p100 (NF-kappaB2) subunit, which also plays a critical role in the regulation of these genes. These data reveal a complex regulatory network integrating NF-kappaB with the DNA-replication checkpoint and the expression of critical regulators of cell proliferation.
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Affiliation(s)
- Benjamin Barré
- Division of Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - Neil D Perkins
- Division of Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, Scotland, UK
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Yun JS, Rust JM, Ishimaru T, Díaz E. A novel role of the Mad family member Mad3 in cerebellar granule neuron precursor proliferation. Mol Cell Biol 2007; 27:8178-89. [PMID: 17893326 PMCID: PMC2169189 DOI: 10.1128/mcb.00656-06] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
During development, Sonic hedgehog (Shh) regulates the proliferation of cerebellar granule neuron precursors (GNPs) in part via expression of Nmyc. We present evidence supporting a novel role for the Mad family member Mad3 in the Shh pathway to regulate Nmyc expression and GNP proliferation. Mad3 mRNA is transiently expressed in GNPs during proliferation. Cultured GNPs express Mad3 in response to Shh stimulation in a cyclopamine-dependent manner. Mad3 is necessary for Shh-dependent GNP proliferation as measured by bromodeoxyuridine incorporation and Nmyc expression. Furthermore, Mad3 overexpression, but not that of other Mad proteins, is sufficient to induce GNP proliferation in the absence of Shh. Structure-function analysis revealed that Max dimerization and recruitment of the mSin3 corepressor are required for Mad3-mediated GNP proliferation. Surprisingly, basic-domain-dependent DNA binding of Mad3 is not required, suggesting that Mad3 interacts with other DNA binding proteins to repress transcription. Interestingly, cerebellar tumors and pretumor cells derived from patched heterozygous mice express high levels of Mad3 compared with adjacent normal cerebellar tissue. Our studies support a novel role for Mad3 in cerebellar GNP proliferation and possibly tumorigenesis, and they challenge the current paradigm that Mad3 should antagonize Nmyc by competition for direct DNA binding via Max dimerization.
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Affiliation(s)
- Jun-Soo Yun
- Department of Pharmacology, UC Davis School of Medicine, Davis, CA 95616, USA
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42
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Kuratomi K, Yano H, Tsuneoka M, Sakamoto K, Kusukawa J, Kojiro M. Immunohistochemical expression of Mina53 and Ki67 proteins in human primary gingival squamous cell carcinoma. Kurume Med J 2007; 53:71-8. [PMID: 17317935 DOI: 10.2739/kurumemedj.53.71] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Studies have reported the presence of relationships between the Myc target gene Mina53 and poor prognostic factors in several cancers including esophageal cancer. In this study, we investigated the relationships between Mina53 expression in gingival squamous cell carcinoma and clinicopathological factors. Seven samples of normal and dysplastic gingival tissues and 15 samples of gingival squamous cell carcinoma were immunostained for Mina53 and Ki67, and examined for the relationships between their expression and differentiation degree, lymph node metastasis, stage, tumor diameter, and prognosis. In normal and dysplastic gingival tissues, the localization of the expression of Mina53 and Ki67 was similar, but that in gingival squamous cell carcinoma tissue varied depending on the degree of differentiation. In well-differentiated GSCC with pearl formation, Mina53 was negative at the center of the clearly keratinized cancer nest, but positive in the nuclei of cells in the periphery and adjacent area of the cancer nest. In diffusely proliferating undifferentiated and moderately-differentiated GSCC showing no pearl formation, both Mina53 tended to be positive in the nuclei of cancer cells in the entire cancer nest. A significant correlation was found between the expression of Mina53 and that of Ki67 in patients with gingival squamous cell carcinoma or dysplastic gingiva. No significant correlation was noted between the expression of Mina53 or Ki67 and prognostic factors such as the degree of differentiation, lymph node metastasis, stage, and tumor diameter. In gingival squamous cell carcinoma, Mina53 expression was correlated with the proliferation of tumor cells, but unlike esophageal and other squamous cell carcinomas, not with the prognosis. The absence of correlations with prognostic factors suggests that may differ gingival squamous cell carcinoma differs biologically from esophageal squamous cell carcinoma which is correlated with Mina53 in terms of the biological expression of Mina53.
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Affiliation(s)
- Keitaro Kuratomi
- Department of Pathology, Kurume University School of Medicine, Kurume, Japan.
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43
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Chen R, Gandhi V, Plunkett W. A sequential blockade strategy for the design of combination therapies to overcome oncogene addiction in chronic myelogenous leukemia. Cancer Res 2006; 66:10959-66. [PMID: 17108134 DOI: 10.1158/0008-5472.can-06-1216] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Some tumors are dependent on the continued activity of a single oncogene for maintenance of their malignant phenotype. The best-studied example is the Bcr-Abl fusion protein in chronic myelogenous leukemia (CML). Although the clinical success of the Abl kinase inhibitor imatinib against chronic-phase CML emphasizes the importance of developing therapeutic strategies aimed at this target, resistance to imatinib poses a major problem for the ultimate success of CML therapy by this agent. We hypothesized a sequential blockade strategy that is designed to decrease the expression of the Bcr-Abl protein, with the goal of complementing the action of imatinib on kinase activity. In this study, flavopiridol, an inhibitor of transcription, homoharringtonine (HHT), a protein synthesis inhibitor, and imatinib were used singly and in combination against the Bcr-Abl-positive human CML cell line K562. Flavopiridol alone inhibited phosphorylation of the RNA polymerase II COOH-terminal domain, specifically reduced RNA polymerase II-directed mRNA synthesis, and decreased the Bcr-Abl transcript levels. HHT inhibited protein synthesis and reduced the Bcr-Abl protein level. Imatinib directly inhibited the kinase activity of Bcr-Abl. The combinations of flavopiridol and HHT and flavopiridol and imatinib synergistically decreased clonogenicity as evaluated by the median-effect method. Greater synergy was observed when HHT and imatinib were given sequentially compared with simultaneous administration. Imatinib-resistant Ba/F3 cells that were transfected to express the E255K and T315I mutations of Bcr-Abl were not cross-resistant to flavopiridol and HHT. These results provided a rationale for the combination of inhibitors of transcription and/or translation with specific kinase inhibitors.
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MESH Headings
- Antineoplastic Combined Chemotherapy Protocols/pharmacology
- Benzamides
- Drug Synergism
- Flavonoids/administration & dosage
- Flavonoids/pharmacology
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/biosynthesis
- Fusion Proteins, bcr-abl/genetics
- Harringtonines/administration & dosage
- Harringtonines/pharmacology
- Homoharringtonine
- Humans
- Imatinib Mesylate
- K562 Cells
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Piperazines/administration & dosage
- Piperazines/pharmacology
- Piperidines/administration & dosage
- Piperidines/pharmacology
- Pyrimidines/administration & dosage
- Pyrimidines/pharmacology
- RNA, Neoplasm/antagonists & inhibitors
- RNA, Neoplasm/biosynthesis
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Affiliation(s)
- Rong Chen
- Department of Experimental Therapeutics, University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA
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Abstract
Deregulation of Myc expression is a common feature in cancer and leads to tumor formation in experimental model systems. There are several potential barriers that Myc must overcome in order to promote tumorigenesis, including its propensity to sensitize many cell types to apoptotic cell death. Myc activities appear also to be constrained and fine-tuned by a set of proteins that include the Mxd (formerly named Mad) family and the related protein Mnt. Like Myc-family proteins, Mxd and Mnt proteins use Max as a cofactor for DNA binding. But Mnt-Max and Mxd-Max complexes are transcriptional repressors and can antagonize the transcriptional activation function of Myc-Max. Studies examining the relationship between Myc, Mxd and Mnt proteins suggest that whereas Mnt plays a general role as a Myc antagonist, Mxd proteins have more specialized roles as Myc antagonist that is probably related to their more restricted expression patterns. The interplay between these proteins is postulated to fine-tune Myc activity for cell-cycle entry and exit, proliferation rate and apoptosis.
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Affiliation(s)
- C William Hooker
- Shriners Hospitals for Children and Department of Cell and Developmental Biology, Oregon Health and Science University, 3101 SW Sam Jackson Park Rd, Portland, OR 97239, USA
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Abstract
Myc regulates to some degree every major process in the cell. Proliferation, growth, differentiation, apoptosis, and metabolism are all under myc control. In turn, these processes feed back to adjust the level of c-myc expression. Although Myc is regulated at every level from RNA synthesis to protein degradation, c-myc transcription is particularly responsive to multiple diverse physiological and pathological signals. These signals are delivered to the c-myc promoter by a wide variety of transcription factors and chromatin remodeling complexes. How these diverse and sometimes disparate signals are processed to manage the output of the c-myc promoter involves chromatin, recruitment of the transcription machinery, post-initiation transcriptional regulation, and mechanisms to provide dynamic feedback. Understanding these mechanisms promises to add new dimensions to models of transcriptional control and to reveal new strategies to manipulate Myc levels.
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Affiliation(s)
- J Liu
- Gene Regulation Section, Laboratory of Pathology, NCI, DCS, Bldg. 10, Rm 2N106, Bethesda, MD 20892-1500, USA
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Takagi M, Absalon MJ, McLure KG, Kastan MB. Regulation of p53 translation and induction after DNA damage by ribosomal protein L26 and nucleolin. Cell 2005; 123:49-63. [PMID: 16213212 DOI: 10.1016/j.cell.2005.07.034] [Citation(s) in RCA: 498] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Revised: 05/31/2005] [Accepted: 07/26/2005] [Indexed: 12/31/2022]
Abstract
Increases in p53 protein levels after DNA damage have largely been attributed to an increase in the half-life of p53 protein. Here we demonstrate that increased translation of p53 mRNA is also a critical step in the induction of p53 protein in irradiated cells. Ribosomal protein L26 (RPL26) and nucleolin were found to bind to the 5' untranslated region (UTR) of p53 mRNA and to control p53 translation and induction after DNA damage. RPL26 preferentially binds to the 5'UTR after DNA damage, and its overexpression enhances association of p53 mRNA with heavier polysomes, increases the rate of p53 translation, induces G1 cell-cycle arrest, and augments irradiation-induced apoptosis. Opposite effects were seen when RPL26 expression was inhibited. In contrast, nucleolin overexpression suppresses p53 translation and induction after DNA damage, whereas nucleolin downregulation promotes p53 expression. These findings demonstrate the importance of increased translation of p53 in DNA-damage responses and suggest critical roles for RPL26 and nucleolin in affecting p53 induction.
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Affiliation(s)
- Masatoshi Takagi
- Department of Hematology-Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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Forte A, Galderisi U, De Feo M, Gomez MF, Esposito S, Santè P, Renzulli A, Agozzino L, Hellstrand P, Berrino L, Cipollaro M, Cotrufo M, Rossi F, Cascino A. c-Myc antisense oligonucleotides preserve smooth muscle differentiation and reduce negative remodelling following rat carotid arteriotomy. J Vasc Res 2005; 42:214-25. [PMID: 15849475 DOI: 10.1159/000085379] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Accepted: 03/13/2005] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES The vascular biology of restenosis is complex and not fully understood, thus explaining the lack of effective therapy for its prevention in clinical settings. The role of c-Myc in arteriotomy-induced stenosis, smooth muscle cell (SMC) differentiation and apoptosis was investigated in rat carotids applying full phosphorothioate antisense (AS) oligonucleotides (ODNs). METHODS Carotid arteries from WKY rats were submitted to arteriotomy and to local application of ODNs through pluronic gel. Apoptosis (deoxynucleotidyl transferase-mediated dUTP nick end-labelling), SMC differentiation (SM22 immunofluorescence) and vessel morphology and morphometry (image analysis) were determined 2, 5 and 30 days after injury, respectively. RESULTS AS ODNs induced a 60% decrease of target c-Myc mRNA 4 h after surgery in comparison to control sense (S) and scrambled ODN-treated carotids (p < 0.05). A significant 37 and 50% decrease in SM22 protein in the media of S ODN-treated and untreated carotids was detected when compared to uninjured contralateral arteries (p < 0.05). This reduction in SM22 expression was prevented in AS ODN-treated carotids. Stenosis was mainly due to adventitial constrictive remodelling. Lumen area in AS ODN-treated carotids was 35% greater than in control arteries 30 days after surgery (p < 0.05). TUNEL assay revealed increased apoptosis in AS ODN-treated carotids (p < 0.05). CONCLUSIONS c-Myc AS ODNs reduce arteriotomy-induced negative remodelling. This is accompanied by maintained SMC differentiation and greater apoptosis. The combination of reduced c-Myc-induced proliferation and increased apoptosis may thus underlie the less severe remodelling upon treatment with c-Myc mRNA AS ODN.
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Affiliation(s)
- Amalia Forte
- Excellence Research Center for Cardiovascular Diseases, Department of Experimental Medicine, Second University of Naples, Via Constantinopoli 16, IT-80138 Naples, Italy
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Weber A, Liu J, Collins I, Levens D. TFIIH operates through an expanded proximal promoter to fine-tune c-myc expression. Mol Cell Biol 2005; 25:147-61. [PMID: 15601838 PMCID: PMC538784 DOI: 10.1128/mcb.25.1.147-161.2005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A continuous stream of activating and repressing signals is processed by the transcription complex paused at the promoter of the c-myc proto-oncogene. The general transcription factor IIH (TFIIH) is held at promoters prior to promoter escape and so is well situated to channel the input of activators and repressors to modulate c-myc expression. We have compared cells expressing only a mutated p89 (xeroderma pigmentosum complementation group B [XPB]), the largest TFIIH subunit, with the same cells functionally complemented with the wild-type protein (XPB/wt-p89). Here, we show structural, compositional, and functional differences in transcription complexes between XPB and XPB/wt-89 cells at the native c-myc promoter. Remarkably, although the mean levels of c-Myc are only modestly elevated in XPB compared to those in XPB/wt-p89 cells, the range of expression and the cell-to-cell variation of c-Myc are markedly increased. Our modeling indicates that the data can be explained if TFIIH integrates inputs from multiple signals, regulating transcription at multiple kinetically equivalent steps between initiation and promoter escape. This helps to suppress the intrinsic noise of transcription and to ensure the steady transcriptional output of c-myc necessary for cellular homeostasis.
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Affiliation(s)
- Achim Weber
- Gene Regulation Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute/NIH, Bldg. 10, Rm. 2N106, Bethesda, MD 20892-1500, USA
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Teye K, Tsuneoka M, Arima N, Koda Y, Nakamura Y, Ueta Y, Shirouzu K, Kimura H. Increased expression of a Myc target gene Mina53 in human colon cancer. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 164:205-16. [PMID: 14695334 PMCID: PMC1602225 DOI: 10.1016/s0002-9440(10)63111-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Mina53 is a novel Myc target gene that we previously demonstrated to be involved in cell proliferation. We studied, here, the expression of Mina53 in colon cancer to examine its possible role in carcinogenesis. We generated a specific monoclonal anti-human Mina53 antibody and found that colon tumor cell lines expressed Mina53 highly. We also found that expression of Mina53 was elevated in colon tumor tissues by immunoblotting analysis. Tissue sections of 23 surgical cases of adenocarcinoma and 1 case of adenoma were stained immunohistochemically, and the expression of Mina53 was found to be elevated in all of the adenocarcinomas compared to adjacent nonneoplastic tissues, which showed little staining. Deeply invading tumors as well as tumors that have invaded lymphatic vessels showed strong immunoreactivity against anti-Mina53 antibody. Mina53 was expressed in all pathological grades of cancer as well as in the adenoma. Staining patterns of Ki-67, a biomarker for cell proliferation, were similar to those of Mina53 in most cases, but the percentage of tumor cells stained by anti-Mina53 was higher. Although anti-Ki-67 antibody strongly stained some well-proliferating nonneoplastic cells including cells in the deeper part of the crypts and in lymphoid germinal centers, antibody to Mina53 rarely stained those cells. Suppression of mina53 expression severely suppressed proliferation of colon tumor cells in vitro. Together, our results indicate that the elevated expression of Mina53 is a characteristic feature in colon cancer, one that may have therapeutic applications.
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Affiliation(s)
- Kwesi Teye
- Department of Forensic Medicine, Kurume University School of Medicine, Kurume, Japan
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Kamemura K, Hart GW. Dynamic interplay between O-glycosylation and O-phosphorylation of nucleocytoplasmic proteins: a new paradigm for metabolic control of signal transduction and transcription. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2004; 73:107-36. [PMID: 12882516 DOI: 10.1016/s0079-6603(03)01004-3] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The glycosylation of serine and threonine residues with beta-O-linked N-acetylglucosamine (O-GlcNAc) is an abundant posttranslational modification of nuclear and cytoplasmic proteins in multicellular eukaryotes. This highly dynamic glycosylation/deglycosylation of protein is catalyzed by the nucleocytoplasmic enzymes, UDP-G1cNAc: polypeptide O-beta-N-acetylglucosaminyltransferase (OGT)/O-beta-N-acetylglucosaminidase. OGT is required for embryonic stem cell viability and mouse ontogeny, thus O-GlcNAc is essential for the life of eukaryotes. The gene encoding O-GlcNAcase maps to a locus important to late-onset Alzheimer's disease. All known O-GlcNAc-modified proteins are also phosphoproteins that form reversible multimeric protein complexes. There is both a global and often site-specific reciprocal relationship between O-GlcNAc and O-phosphate in many cellular responses to stimuli. Thus, regulation of the protein-protein interaction(s) and/or protein function by dynamic glycosylation/phosphorylation has been hypothesized. In this chapter, we will review the current status of dynamic glycosylation/phosphorylation of several important regulatory proteins including c-Myc, estrogen receptors, Sp1, endothelial nitric oxide synthase, and beta-catenin. Various aspects of subcellular localization, association with binding partners, activity, and/or turnover of these proteins appear to be regulated by dynamic glycosylation/ phosphorylation in response to cellular signals or stages.
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Affiliation(s)
- Kazuo Kamemura
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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