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Qi Y, Li L, Wei Y, Ma F. PP2A as a potential therapeutic target for breast cancer: Current insights and future perspectives. Biomed Pharmacother 2024; 173:116398. [PMID: 38458011 DOI: 10.1016/j.biopha.2024.116398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 02/28/2024] [Accepted: 03/06/2024] [Indexed: 03/10/2024] Open
Abstract
Breast cancer has become the most prevalent malignancy worldwide; however, therapeutic efficacy is far from satisfactory. To alleviate the burden of this disease, it is imperative to discover novel mechanisms and treatment strategies. Protein phosphatase 2 A (PP2A) comprises a family of mammalian serine/threonine phosphatases that regulate many cellular processes. PP2A is dysregulated in several human diseases, including oncological pathologies, and plays a pivotal role in the initiation and progression of tumours. The role of PP2A as a tumour suppressor has been extensively studied, and its regulation can serve as a target for anticancer therapy. Recent studies have shown that PP2A is a tumour promotor. PP2A-mediated anticancer therapy may involve two opposing mechanisms: activation and inhibition. In general, the contradictory roles of PP2A should not be overlooked, and more work is needed to determine the molecular mechanism by which PP2A affects in tumours. In this review, the literature on the role of PP2A in tumours, especially in breast cancer, was analysed. This review describes relevant targets of breast cancer, such as cell cycle control, DNA damage responses, epidermal growth factor receptor, immune modulation and cell death resistance, which may lead to effective therapeutic strategies or influence drug development in breast cancer.
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Affiliation(s)
- Yalong Qi
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China
| | - Lixi Li
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China
| | - Yuhan Wei
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China
| | - Fei Ma
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China.
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2
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Player A, Cunningham S, Philio D, Roy R, Haynes C, Dixon C, Thirston L, Ibikunle F, Boswell TA, Alnakhalah A, Contreras J, Bell M, McGuffery T, Bryant S, Nganya C, Kanu S. Characterization of MYBL1 Gene in Triple-Negative Breast Cancers and the Genes' Relationship to Alterations Identified at the Chromosome 8q Loci. Int J Mol Sci 2024; 25:2539. [PMID: 38473786 DOI: 10.3390/ijms25052539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/14/2024] Open
Abstract
The MYBL1 gene is a strong transcriptional activator involved in events associated with cancer progression. Previous data show MYBL1 overexpressed in triple-negative breast cancer (TNBC). There are two parts to this study related to further characterizing the MYBL1 gene. We start by characterizing MYBL1 reference sequence variants and isoforms. The results of this study will help in future experiments in the event there is a need to characterize functional variants and isoforms of the gene. In part two, we identify and validate expression and gene-related alterations of MYBL1, VCIP1, MYC and BOP1 genes in TNBC cell lines and patient samples selected from the Breast Invasive Carcinoma TCGA 2015 dataset available at cBioPortal.org. The four genes are located at chromosomal regions 8q13.1 to 8q.24.3 loci, regions previously identified as demonstrating a high percentage of alterations in breast cancer. We identify alterations, including changes in expression, deletions, amplifications and fusions in MYBL1, VCPIP1, BOP1 and MYC genes in many of the same patients, suggesting the panel of genes is involved in coordinated activity in patients. We propose that MYBL1, VCPIP1, MYC and BOP1 collectively be considered as genes associated with the chromosome 8q loci that potentially play a role in TNBC pathogenesis.
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Affiliation(s)
- Audrey Player
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Sierra Cunningham
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Deshai Philio
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Renata Roy
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Cydney Haynes
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Christopher Dixon
- Department of Environmental and Interdisciplinary Sciences, Texas Southern University, Houston, TX 77004, USA
| | - Lataja Thirston
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Fawaz Ibikunle
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | | | - Ayah Alnakhalah
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Juan Contreras
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Myra Bell
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Treveon McGuffery
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Sahia Bryant
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Chidinma Nganya
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
| | - Samuel Kanu
- Department of Biology, Texas Southern University, Houston, TX 77004, USA
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3
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Pandkar MR, Sinha S, Samaiya A, Shukla S. Oncometabolite lactate enhances breast cancer progression by orchestrating histone lactylation-dependent c-Myc expression. Transl Oncol 2023; 37:101758. [PMID: 37572497 PMCID: PMC10425713 DOI: 10.1016/j.tranon.2023.101758] [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: 06/15/2023] [Revised: 07/22/2023] [Accepted: 08/07/2023] [Indexed: 08/14/2023] Open
Abstract
Due to the enhanced glycolytic rate, cancer cells generate lactate copiously, subsequently promoting the lactylation of histones. While previous studies have explored the impact of histone lactylation in modulating gene expression, the precise role of this epigenetic modification in regulating oncogenes is largely unchartered. In this study, using breast cancer cell lines and their mutants exhibiting lactate-deficient metabolome, we have identified that an enhanced rate of aerobic glycolysis supports c-Myc expression via promoter-level histone lactylation. Interestingly, c-Myc further transcriptionally upregulates serine/arginine splicing factor 10 (SRSF10) to drive alternative splicing of MDM4 and Bcl-x in breast cancer cells. Moreover, our results reveal that restricting the activity of critical glycolytic enzymes affects the c-Myc-SRSF10 axis to subside the proliferation of breast cancer cells. Our findings provide novel insights into the mechanisms by which aerobic glycolysis influences alternative splicing processes that collectively contribute to breast tumorigenesis. Furthermore, we also envisage that chemotherapeutic interventions attenuating glycolytic rate can restrict breast cancer progression by impeding the c-Myc-SRSF10 axis.
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Affiliation(s)
- Madhura R Pandkar
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh 462066, India. https://twitter.com/https://twitter.com/MadhuraPandkar
| | - Sommya Sinha
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh 462066, India. https://twitter.com/https://twitter.com/sinha_sommya
| | - Atul Samaiya
- Department of Surgical Oncology, Bansal Hospital, Bhopal, Madhya Pradesh 462016, India
| | - Sanjeev Shukla
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh 462066, India.
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4
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Daniel CJ, Pelz C, Wang X, Munks MW, Ko A, Murugan D, Byers SA, Juarez E, Taylor KL, Fan G, Coussens LM, Link JM, Sears RC. T-cell dysfunction upon expression of MYC with altered phosphorylation at Threonine 58 and Serine 62. Mol Cancer Res 2022; 20:1151-1165. [PMID: 35380701 DOI: 10.1158/1541-7786.mcr-21-0560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 03/01/2022] [Accepted: 03/29/2022] [Indexed: 11/16/2022]
Abstract
As a transcription factor that promotes cell growth, proliferation and apoptosis, c-MYC (MYC) expression in the cell is tightly controlled. Disruption of oncogenic signaling pathways in human cancers can increase MYC protein stability, due to altered phosphorylation ratios at two highly conserved sites, Threonine 58 (T58) and Serine 62 (S62). The T58 to Alanine mutant (T58A) of MYC mimics the stabilized, S62 phosphorylated, and highly oncogenic form of MYC. The S62A mutant is also stabilized, lacks phosphorylation at both Serine 62 and Threonine 58, and has been shown to be non-transforming in vitro. However, several regulatory proteins are reported to associate with MYC lacking phosphorylation at S62 and T58, and the role this form of MYC plays in MYC transcriptional output and in vivo oncogenic function is understudied. We generated conditional c-Myc knock-in mice in which the expression of wild-type MYC (MYCWT), the T58A mutant (MYCT58A), or the S62A mutant (MYCS62A) with or without expression of endogenous Myc is controlled by the T-cell-specific Lck-Cre recombinase. MYCT58A expressing mice developed clonal T-cell lymphomas with 100% penetrance and conditional knock-out of endogenous Myc accelerated this lymphomagenesis. In contrast, MYCS62A mice developed clonal T-cell lymphomas at a much lower penetrance, and the loss of endogenous MYC reduced the penetrance while increasing the appearance of a non-transgene driven B-cell lymphoma with splenomegaly. Together, our study highlights the importance of regulated phosphorylation of MYC at T58 and S62 for T-cell transformation. Implications: Dysregulation of phosphorylation at conserved T58 and S62 residues of MYC differentially affects T-cell development and lymphomagenesis.
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Affiliation(s)
- Colin J Daniel
- Oregon Health & Science University, Portland, OR, United States
| | - Carl Pelz
- Oregon Health & Science University, Portland, OR, United States
| | - Xiaoyan Wang
- Oregon Health & Science University, Portland, Oregon, United States
| | - Michael W Munks
- Oregon Health & Science University, Portland, OR, United States
| | - Aaron Ko
- Oregon Health & Science University, Portland, OR, United States
| | | | - Sarah A Byers
- Oregon Health & Science University, Portland, OR, United States
| | - Eleonora Juarez
- Oregon Health & Science University, Portland, OR, United States
| | - Karyn L Taylor
- Oregon Health & Science University, Portland, OR, United States
| | - Guang Fan
- Oregon Health & Science University Knight Cancer Institute, Portland, OR, United States
| | - Lisa M Coussens
- Oregon Health & Science University, Portland, OR, United States
| | - Jason M Link
- Oregon Health & Science University, Portland, Oregon, United States
| | - Rosalie C Sears
- Oregon Health & Science University, Portland, Oregon, United States
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5
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Wang CY, Yu N, Wu MJ, Gao YL, Liu JX, Wang J. Dual Hyper-Graph Regularized Supervised NMF for Selecting Differentially Expressed Genes and Tumor Classification. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2021; 18:2375-2383. [PMID: 32086220 DOI: 10.1109/tcbb.2020.2975173] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Non-negative matrix factorization (NMF) is a dimensionality reduction technique based on high-dimensional mapping. It can learn part-based representations effectively. In this paper, we propose a method called Dual Hyper-graph Regularized Supervised Non-negative Matrix Factorization (HSNMF). To encode the geometric information of the data, the hyper-graph is introduced into the model as a regularization term. The advantage of hyper-graph learning is to find higher order data relationship to enhance data relevance. This method constructs the data hyper-graph and the feature hyper-graph to find the data manifold and the feature manifold simultaneously. The application of hyper-graph theory in cancer datasets can effectively find pathogenic genes. The discrimination information is further introduced into the objective function to obtain more information about the data. Supervised learning with label information greatly improves the classification effect. Furthermore, the real datasets of cancer usually contain sparse noise, so the L2,1-norm is applied to enhance the robustness of HSNMF algorithm. Experiments under The Cancer Genome Atlas (TCGA) datasets verify the feasibility of the HSNMF method.
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6
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MMTV-LIKE virus and c-myc over-expression are associated with invasive breast cancer. INFECTION GENETICS AND EVOLUTION 2021; 91:104827. [PMID: 33794352 DOI: 10.1016/j.meegid.2021.104827] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 12/15/2022]
Abstract
Development and progression of breast cancer is an outcome of strong interplay between proto-oncogenes as well as environmental factors. Among proto-oncogenes, c-myc, a multifunctional transcription factor (TF), is one of the most highlighted one, whereas among environmental factors Mouse Mammary Tumor Virus (MMTV)-like virus is a widely discussed agent. Both, c-myc and MMTV-like virus, are known to individually correlate with the poor prognosis of breast cancer. However, no study has ever been reported to determine their mutual association in breast cancer patients. In this study, our aim was to quantify and compare c-myc mRNA in MMTV-like virus-positive and virus-negative-histopathological types of breast cancer. At first, biopsy samples of 105 breast cancer patients with known histopathological types were collected and screened for the presence of MMTV-like virus. To quantify mRNA level of c-myc, quantitative-Polymerase Chain Reaction (qPCR) was used. Next, c-myc expression was compared in MMTV-like virus-positive and virus-negative-histopathological types as of breast cancer. Statistical analysis was done using GraphPad Prism 7 Software. Molecular analysis revealed that 69 (65.72%) out of 105 samples were positive for MMTV-like virus. Moreover, invasive types of breast cancer exhibited increased (3-13 folds higher) expression of c-myc as compared to baseline representing normal control comprising of 15 tumor-free biopsy samples of breast cancer patients. Whereas, non-invasive types of breast cancer showed only 1-3 folds increase in the expression of c-myc as compared to normal control. Furthermore, virus-positive and virus-negative samples had different levels of c-myc mRNA. Positive status of MMTV-like virus was noticed to significantly associate with c-myc expression increasing it from 1.87-folds in virus-negative patient samples to 4.31-folds in virus-positive patient samples (p-value: <0.0001). Whereas, increase in the expression of c-myc was only 1.14-folds higher in 2 (13.33%) virus-positive-normal control samples as compared to 13 (86.67%) virus-negative-normal control samples (P-value: <0.01). In conclusion, it is suggested that presence of MMTV-like virus and over-expression of c-myc may be used as markers of invasion of breast cancer.
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7
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Chacón Simon S, Wang F, Thomas LR, Phan J, Zhao B, Olejniczak ET, Macdonald JD, Shaw JG, Schlund C, Payne W, Creighton J, Stauffer SR, Waterson AG, Tansey WP, Fesik SW. Discovery of WD Repeat-Containing Protein 5 (WDR5)-MYC Inhibitors Using Fragment-Based Methods and Structure-Based Design. J Med Chem 2020; 63:4315-4333. [PMID: 32223236 DOI: 10.1021/acs.jmedchem.0c00224] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The frequent deregulation of MYC and its elevated expression via multiple mechanisms drives cells to a tumorigenic state. Indeed, MYC is overexpressed in up to ∼50% of human cancers and is considered a highly validated anticancer target. Recently, we discovered that WD repeat-containing protein 5 (WDR5) binds to MYC and is a critical cofactor required for the recruitment of MYC to its target genes and reported the first small molecule inhibitors of the WDR5-MYC interaction using structure-based design. These compounds display high binding affinity, but have poor physicochemical properties and are hence not suitable for in vivo studies. Herein, we conducted an NMR-based fragment screening to identify additional chemical matter and, using a structure-based approach, we merged a fragment hit with the previously reported sulfonamide series. Compounds in this series can disrupt the WDR5-MYC interaction in cells, and as a consequence, we observed a reduction of MYC localization to chromatin.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Shaun R Stauffer
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Alex G Waterson
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37232, United States
| | | | - Stephen W Fesik
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37232, United States
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8
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Rosselot C, Kumar A, Lakshmipathi J, Zhang P, Lu G, Katz LS, Prochownik EV, Stewart AF, Lambertini L, Scott DK, Garcia-Ocaña A. Myc Is Required for Adaptive β-Cell Replication in Young Mice but Is Not Sufficient in One-Year-Old Mice Fed With a High-Fat Diet. Diabetes 2019; 68:1934-1949. [PMID: 31292135 PMCID: PMC6754239 DOI: 10.2337/db18-1368] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 07/02/2019] [Indexed: 12/18/2022]
Abstract
Failure to expand pancreatic β-cells in response to metabolic stress leads to excessive workload resulting in β-cell dysfunction, dedifferentiation, death, and development of type 2 diabetes. In this study, we demonstrate that induction of Myc is required for increased pancreatic β-cell replication and expansion during metabolic stress-induced insulin resistance with short-term high-fat diet (HFD) in young mice. β-Cell-specific Myc knockout mice fail to expand adaptively and show impaired glucose tolerance and β-cell dysfunction. Mechanistically, PKCζ, ERK1/2, mTOR, and PP2A are key regulators of the Myc response in this setting. DNA methylation analysis shows hypomethylation of cell cycle genes that are Myc targets in islets from young mice fed with a short-term HFD. Importantly, DNA hypomethylation of Myc response elements does not occur in islets from 1-year-old mice fed with a short-term HFD, impairing both Myc recruitment to cell cycle regulatory genes and β-cell replication. We conclude that Myc is required for metabolic stress-mediated β-cell expansion in young mice, but with aging, Myc upregulation is not sufficient to induce β-cell replication by, at least partially, an epigenetically mediated resistance to Myc action.
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Affiliation(s)
- Carolina Rosselot
- Division of Endocrinology, Diabetes and Bone Diseases, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Anil Kumar
- Division of Endocrinology, Diabetes and Bone Diseases, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Jayalakshmi Lakshmipathi
- Division of Endocrinology, Diabetes and Bone Diseases, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Pili Zhang
- Division of Endocrinology, Diabetes and Bone Diseases, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Geming Lu
- Division of Endocrinology, Diabetes and Bone Diseases, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Liora S Katz
- Division of Endocrinology, Diabetes and Bone Diseases, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Edward V Prochownik
- Division of Hematology/Oncology, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA
- Department of Microbiology & Molecular Genetics, University of Pittsburgh Medical Center, Hillman Cancer Center, and Pittsburgh Liver Research Center, Pittsburgh, PA
| | - Andrew F Stewart
- Division of Endocrinology, Diabetes and Bone Diseases, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Luca Lambertini
- Division of Endocrinology, Diabetes and Bone Diseases, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Donald K Scott
- Division of Endocrinology, Diabetes and Bone Diseases, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Adolfo Garcia-Ocaña
- Division of Endocrinology, Diabetes and Bone Diseases, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
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9
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Ferreira D, Martins B, Soares M, Correia J, Adega F, Ferreira F, Chaves R. Gene expression association study in feline mammary carcinomas. PLoS One 2019; 14:e0221776. [PMID: 31461477 PMCID: PMC6713336 DOI: 10.1371/journal.pone.0221776] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/14/2019] [Indexed: 12/15/2022] Open
Abstract
Works on cancer-related genes expression using feline mammary carcinomas (FMCs) are scarce but crucial, not only to validate these tumours as models for human breast cancer studies but also to improve small animal practice. Here, the expression of the cancer-related genes TP53, CCND1, FUS, YBX1, PTBP1, c-MYC and PKM2 was evaluated by real-time RT-qPCR, in a population of FMCs clinically characterized and compared with the disease-free tissue of the same individual. In most of the FMCs analysed, RNA quantification revealed normal expression levels for TP53, c-MYC, YBX1 and FUS, but overexpression in the genes CCND1, PTBP1 and PKM2. The expression levels of these cancer-related genes are strongly correlated with each other, with exception of c-MYC and PKM2 genes. The integration of clinicopathological data with the transcriptional levels revealed several associations. The oral contraceptive administration showed to be positively related with the TP53, YBX1, CCND1, FUS and PTBP1 RNA levels. Positive associations were found between tumour size and YBX1 RNA, and lymph node metastasis with c-MYC RNA levels. This work allowed to verify that many of these cancer-related genes are associated but may also, indirectly, influence other genes, creating a complex molecular cancer network that in the future can provide new cancer biomarkers.
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Affiliation(s)
- Daniela Ferreira
- CAG - Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
| | - Bárbara Martins
- CAG - Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal
| | - Maria Soares
- CBiOS - Research Center for Biosciences & Health Technologies, Faculdade de Medicina Veterinária, Universidade Lusófona de Humanidades e Tecnologias, Lisbon, Portugal
| | - Jorge Correia
- CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, Lisboa, Portugal
| | - Filomena Adega
- CAG - Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
| | - Fernando Ferreira
- CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, Lisboa, Portugal
| | - Raquel Chaves
- CAG - Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
- * E-mail:
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10
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Tokgun PE, Tokgun O, Kurt S, Tomatir AG, Akca H. MYC-driven regulation of long non-coding RNA profiles in breast cancer cells. Gene 2019; 714:143955. [PMID: 31326549 DOI: 10.1016/j.gene.2019.143955] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 06/27/2019] [Accepted: 06/28/2019] [Indexed: 11/25/2022]
Abstract
AIM MYC deregulation contributes to breast cancer development and progression. Deregulated expression levels of long non-coding RNAs (lncRNA) have been demonstrated to be critical players in development and/or maintenance of breast cancer. In this study we aimed to evaluate lncRNA expressions depending on MYC overexpression and knockdown in breast cancer cells. MATERIALS AND METHODS Cells were infected with lentiviral vectors by either knockdown or overexpression of c-MYC. LncRNA cDNA was transcribed from total RNA samples and lncRNAs were evaluated by qRT-PCR. RESULTS Our results indicated that some of the lncRNAs having tumor suppressor (GAS5, MEG3, lincRNA-p21) and oncogenic roles (HOTAIR) are regulated by c-MYC. CONCLUSION We observed that c-MYC regulates lncRNAs that have important roles on proliferation, cell cycle and etc. Further studies will give us a light to identify molecular mechanisms related to MYC-lncRNA regulatory pathways in breast cancer.
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Affiliation(s)
- Pervin Elvan Tokgun
- Department of Medical Genetics, Faculty of Medicine, Pamukkale University, Denizli, Turkey.
| | - Onur Tokgun
- Department of Medical Genetics, Faculty of Medicine, Pamukkale University, Denizli, Turkey.
| | - Serap Kurt
- Department of Medical Biology, Faculty of Medicine, Pamukkale University, Denizli, Turkey.
| | - Ayse Gaye Tomatir
- Department of Medical Biology, Faculty of Medicine, Pamukkale University, Denizli, Turkey.
| | - Hakan Akca
- Department of Medical Genetics, Faculty of Medicine, Pamukkale University, Denizli, Turkey.
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11
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Khan F, Ricks-Santi LJ, Zafar R, Kanaan Y, Naab T. Expression of p27 and c-Myc by immunohistochemistry in breast ductal cancers in African American women. Ann Diagn Pathol 2018; 34:170-174. [PMID: 29715580 PMCID: PMC6008231 DOI: 10.1016/j.anndiagpath.2018.03.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 12/30/2017] [Accepted: 03/30/2018] [Indexed: 10/17/2022]
Abstract
OBJECTIVES Proteins p27 and c-Myc are both key players in the cell cycle. While p27, a tumor suppressor, inhibits progression from G1 to S phase, c-Myc, a proto-oncogene, plays a key role in cell cycle regulation and apoptosis. The objective of our study was to determine the association between expression of c-Myc and the loss of p27 by immunohistochemistry (IHC) in the four major subtypes of breast cancer (BC) (Luminal A, Luminal B, HER2, and Triple Negative) and with other clinicopathological factors in a population of 202 African-American (AA) women. MATERIALS AND METHODS Tissue microarrays (TMAs) were constructed from FFPE tumor blocks from primary ductal breast carcinomas in 202 AA women. Five micrometer sections were stained with a mouse monoclonal antibody against p27 and a rabbit monoclonal antibody against c-Myc. The sections were evaluated for intensity of nuclear reactivity (1-3) and percentage of reactive cells; an H-score was derived from the product of these measurements. RESULTS Loss of p27 expression and c-Myc overexpression showed statistical significance with ER negative (p < 0.0001), PR negative (p < 0.0001), triple negative (TN) (p < 0.0001), grade 3 (p = 0.038), and overall survival (p = 0.047). There was no statistical significant association between c-Myc expression/p27 loss and luminal A/B and Her2 overexpressing subtypes. CONCLUSION In our study, a statistically significant association between c-Myc expression and p27 loss and the triple negative breast cancers (TNBC) was found in AA women. A recent study found that constitutive c-Myc expression is associated with inactivation of the axin 1 tumor suppressor gene. p27 inhibits cyclin dependent kinase2/cyclin A/E complex formation. Axin 1 and CDK inhibitors may represent possible therapeutic targets for TNBC.
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Affiliation(s)
- Farhan Khan
- Department of Pathology, Howard University College of Medicine, Washington, DC, United States.
| | - Luisel J Ricks-Santi
- Department of Biological Sciences, Hampton University, Hampton, VA, United States
| | - Rabia Zafar
- Department of Pathology, Howard University College of Medicine, Washington, DC, United States
| | - Yasmine Kanaan
- Department of Microbiology, Howard University College of Medicine, Washington, DC, United States
| | - Tammey Naab
- Department of Pathology, Howard University College of Medicine, Washington, DC, United States
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12
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Naab TJ, Gautam A, Ricks-Santi L, Esnakula AK, Kanaan YM, DeWitty RL, Asgedom G, Makambi KH, Abawi M, Blancato JK. MYC amplification in subtypes of breast cancers in African American women. BMC Cancer 2018. [PMID: 29523126 PMCID: PMC5845301 DOI: 10.1186/s12885-018-4171-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background MYC overexpression is associated with poor prognosis in breast tumors (BCa). The objective of this study was to determine the prevalence of MYC amplification and associated markers in BCa tumors from African American (AA) women and determine the associations between MYC amplification and clinico-pathological characteristics. Methods We analyzed 70 cases of well characterized archival breast ductal carcinoma specimens from AA women for MYC oncogene amplification. Utilizing immune histochemical analysis estrogen receptor (ER), progesterone receptor (PR), and (HER2/neu), were assessed. Cases were Luminal A (ER or PR+, Ki-67 < 14%), Luminal B (ER or PR+, Ki-67 = > 14% or ER or PR+ HER2+), HER2 (ER-, PR-, HER2+), and Triple Negative (ER-, PR-, HER2-) with basal-like phenotype. The relationship between MYC amplification and prognostic clinico-pathological characteristics was determined using chi square and logistic regression modeling. Results Sixty-five (97%) of the tumors showed MYC gene amplification (MYC: CEP8 > 1). Statistically significant associations were found between MYC amplification and HER2-amplified BCa, and Luminal B subtypes of BCa (p < 0.0001), stage (p < 0.001), metastasis (p < 0.001), and positive lymph node status (p = 0.039). MYC amplification was associated with HER2 status (p = 0.01) and tumor size (p = 0.01). High MYC amplification was seen in grade III carcinomas (MYC: CEP8 = 2.42), pre-menopausal women (MYC: CEP8 = 2.49), PR-negative status (MYC: CEP8 = 2.42), and ER-positive status (MYC: CEP8 = 2.4). Conclusions HER2 positive BCas in AA women are likely to exhibit MYC amplification. High amplification ratios suggest that MYC drives HER2 amplification, especially in HER2 positive, Luminal B, and subtypes of BCa.
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Affiliation(s)
- Tammey J Naab
- Department of Pathology, Howard University College of Medicine, Howard University Hospital, 2041 Georgia Avenue Rm. 1M-06, Washington DC, NW, 20060, USA
| | - Anita Gautam
- Department of Oncology, University of Massachusetts Medical School, 373 Plantation street Suite# 318, Worcester, MA, 01581, England
| | - Luisel Ricks-Santi
- Cancer Research Center, Department of Biological Sciences, Hampton University, 100 E. Queen Street, Hampton, VA, 23668, USA
| | - Ashwini K Esnakula
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, P.O. Box 100275, 1600 SW Archer Road, Gainesville, FL, 32610-0275, USA
| | - Yasmine M Kanaan
- Department of Microbiology, Howard University College of Medicine, 2041 Georgia Avenue Rm. 1M-06, Washington DC, NW, 20060, USA
| | - Robert L DeWitty
- Department of Surgery, Howard University Hospital, 2041 Georgia Avenue, Washington DC, NW, 20060, USA
| | - Girmay Asgedom
- Department of Medicine, Howard University Hospital, 2041 Georgia Avenue, Washington DC, NW, 20060, USA
| | - Khepher H Makambi
- Department of Biostatistics, Bioinformatics, and Biomathematics, Lombardi Comprehensive Cancer Center, Georgetown University, 4000 Reservoir Road, Washington, DC, NW, 20057, USA
| | - Massih Abawi
- Inherited Cancer Program, GeneDx, 207 Perry Pkwy, Gaithersburg, MD, 20877, USA
| | - Jan K Blancato
- Department of Oncology, Lombardi Comprehensive Cancer Centre, Georgetown University Medical Centre, 3800 Reservoir Road, Washington DC, NW, 20007, USA.
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13
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High Myc expression and transcription activity underlies intra-tumoral heterogeneity in triple-negative breast cancer. Oncotarget 2018; 8:28101-28115. [PMID: 28427212 PMCID: PMC5438634 DOI: 10.18632/oncotarget.15891] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 02/21/2017] [Indexed: 01/11/2023] Open
Abstract
We have previously identified a novel intra-tumoral dichotomy in triple-negative breast cancer (TNBC) based on the differential responsiveness to a reporter containing the Sox2 regulatory region-2 (SRR2), with reporter responsive (RR) cells being more stem-like than reporter unresponsive (RU) cells. Using bioinformatics, we profiled the protein-DNA binding motifs of SRR2 and identified Myc as one of the potential transcription factors driving SRR2 activity. In support of its role, Myc was found to be highly expressed in RR cells as compared to RU cells. Enforced expression of MYC in RU cells resulted in a significant increase in SRR2 activity, Myc-DNA binding, proportion of cellsexpressing CD44+/CD24-, chemoresistance and mammosphere formation. Knockdown of Myc using siRNA in RR cells led to the opposite effects. We also found evidence that the relatively high ERK activation in RR cells contributes to their high expression of Myc and stem-like features. Using confocal microscopy and patient samples, we found a co-localization between Myc and CD44 in the same cell population. Lastly, a high proportion of Myc-positive cells in tumors significantly correlated with a short patient survival. In conclusion, inhibition of the MAPK/ERK/Myc axis may be an effective approach in eliminating stem-like cells in TNBC.
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14
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microRNA-206 impairs c-Myc-driven cancer in a synthetic lethal manner by directly inhibiting MAP3K13. Oncotarget 2017; 7:16409-19. [PMID: 26918941 PMCID: PMC4941324 DOI: 10.18632/oncotarget.7653] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/05/2016] [Indexed: 12/18/2022] Open
Abstract
c-Myc (Myc) is one of the most frequently dysregulated oncogenic transcription factors in human cancer. By functionally screening a microRNA (miR) library, we identified miR-206 as being a synthetic lethal in Myc over-expressing human cancer cells. miR-206 inhibited MAP3K13, which resulted in Myc protein de-stabilization, and an inhibition of anchorage-independent growth and in vivo tumorigenesis by Myc over-expressing human cancer cells. Eliminating MAP3K13 by shRNA recapitulated the effects caused by miR-206, thus supporting the idea that miR-206's effect on Myc was mediated through MAP3K13. Conversely, enforced expression of MAP3K13 stabilized Myc by promoting its N-terminal phosphorylation and enhancing its transcriptional activity. Gene expression analyses of breast cancers expressing high levels of Myc indicated that low miR-206 expression and high MAP3K13 expression correlated with poor patient survival. The critical link between miR-206 and MAP3K13 in the development of Myc over-expressing human cancers suggests potential points of therapeutic intervention for this molecular sub-category.
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15
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Myc mediates cancer stem-like cells and EMT changes in triple negative breast cancers cells. PLoS One 2017; 12:e0183578. [PMID: 28817737 PMCID: PMC5560738 DOI: 10.1371/journal.pone.0183578] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 08/07/2017] [Indexed: 12/12/2022] Open
Abstract
Women with triple negative breast cancer (TNBC) have poor prognosis compared to other breast cancer subtypes. There were several reports indicating racial disparity in breast cancer outcomes between African American (AA) and European American (EA) women. For example, the mortality rates of AA breast cancer patients were three times higher than of EA patients, even though, the incidence is lower in AA women. Our in vitro studies indicate that cancer stem-like cells (CSCs) derived from AA TNBC cell lines have significantly higher self-renewal potential (mammosphere formation) than CSCs derived from EA cell lines. TNBC tumors express high levels of Myc compared to luminal A or HER2 expressing breast cancers. We studied the effects of c-Myc overexpression on CSCs and chemotherapy in AA, and EA derived TNBC cell line(s). Overexpression of c-Myc in AA derived MDA-MB-468 (Myc/MDA-468) cells resulted in a significant increase in CSCs and with minimal changes in epithelial-to-mesenchymal transition (EMT) compared to the control group. In contrast, overexpression of c-Myc in EA derived MDA-MB-231(Myc/MDA-231) cells led to increased epithelial-to-mesenchymal transition (EMT), with a minimal increase in CSCs compared to the control group. Myc/MDA-468 cells were resistant to standard chemotherapeutic treatments such as iniparib (PARP inhibitor) plus cisplatin, / iniparib, cisplatin, paclitaxel and docetaxel. However, Myc/MDA-231 cells, which showed EMT changes responded to iniparib with cisplatin, but were resistant to other drugs, such as iniparib, cisplatin, paclitaxel and docetaxel. Collectively, our results indicate that intrinsic differences in the tumor biology may contribute to the breast cancer disparities.
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16
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17
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Zelenko Z, Gallagher EJ, Antoniou IM, Sachdev D, Nayak A, Yee D, LeRoith D. EMT reversal in human cancer cells after IR knockdown in hyperinsulinemic mice. Endocr Relat Cancer 2016; 23:747-58. [PMID: 27435064 PMCID: PMC4990486 DOI: 10.1530/erc-16-0142] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 07/19/2016] [Indexed: 12/26/2022]
Abstract
Type 2 diabetes (T2D) is associated with increased cancer risk and cancer-related mortality. Data herein show that we generated an immunodeficient hyperinsulinemic mouse by crossing the Rag1(-/-) mice, which have no mature B or T lymphocytes, with the MKR mouse model of T2D to generate the Rag1(-/-) (Rag/WT) and Rag1(-/-)/MKR(+/+) (Rag/MKR) mice. The female Rag/MKR mice are insulin resistant and have significantly higher nonfasting plasma insulin levels compared with the Rag/WT controls. Therefore, we used these Rag/MKR mice to investigate the role of endogenous hyperinsulinemia on human cancer progression. In this study, we show that hyperinsulinemia in the Rag/MKR mice increases the expression of mesenchymal transcription factors, TWIST1 and ZEB1, and increases the expression of the angiogenesis marker, vascular endothelial growth factor A (VEGFA). We also show that silencing the insulin receptor (IR) in the human LCC6 cancer cells leads to decreased tumor growth and metastases, suppression of mesenchymal markers vimentin, SLUG, TWIST1 and ZEB1, suppression of angiogenesis markers, VEGFA and VEGFD, and re-expression of the epithelial marker, E-cadherin. The data in this paper demonstrate that IR knockdown in primary tumors partially reverses the growth-promoting effects of hyperinsulinemia as well as highlighting the importance of the insulin receptor signaling pathway in cancer progression, and more specifically in epithelial-mesenchymal transition.
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MESH Headings
- Animals
- Cell Line, Tumor
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/pathology
- Disease Models, Animal
- Epithelial-Mesenchymal Transition
- Female
- Gene Silencing
- Humans
- Hyperinsulinism/genetics
- Hyperinsulinism/metabolism
- Hyperinsulinism/pathology
- Male
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/metabolism
- Mammary Neoplasms, Experimental/pathology
- Mice, Transgenic
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Receptor, Insulin/genetics
- Receptor, Insulin/metabolism
- Signal Transduction
- Snail Family Transcription Factors/genetics
- Snail Family Transcription Factors/metabolism
- Twist-Related Protein 1/genetics
- Twist-Related Protein 1/metabolism
- Vascular Endothelial Growth Factor A
- Vimentin/metabolism
- Zinc Finger E-box-Binding Homeobox 1/genetics
- Zinc Finger E-box-Binding Homeobox 1/metabolism
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Affiliation(s)
- Zara Zelenko
- Division of EndocrinologyDiabetes and Bone Diseases, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Emily Jane Gallagher
- Division of EndocrinologyDiabetes and Bone Diseases, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Irini Markella Antoniou
- Division of EndocrinologyDiabetes and Bone Diseases, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Deepali Sachdev
- Department of Medicine and Masonic Cancer CenterUniversity of Minnesota, Minneapolis, Minnesota, USA
| | - Anupma Nayak
- Department of Pathology and Laboratory MedicineThe Mount Sinai Hospital and Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Douglas Yee
- Department of Medicine and Masonic Cancer CenterUniversity of Minnesota, Minneapolis, Minnesota, USA
| | - Derek LeRoith
- Division of EndocrinologyDiabetes and Bone Diseases, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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18
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Danforth DN. Genomic Changes in Normal Breast Tissue in Women at Normal Risk or at High Risk for Breast Cancer. BREAST CANCER-BASIC AND CLINICAL RESEARCH 2016; 10:109-46. [PMID: 27559297 PMCID: PMC4990153 DOI: 10.4137/bcbcr.s39384] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/17/2016] [Accepted: 04/19/2016] [Indexed: 12/12/2022]
Abstract
Sporadic breast cancer develops through the accumulation of molecular abnormalities in normal breast tissue, resulting from exposure to estrogens and other carcinogens beginning at adolescence and continuing throughout life. These molecular changes may take a variety of forms, including numerical and structural chromosomal abnormalities, epigenetic changes, and gene expression alterations. To characterize these abnormalities, a review of the literature has been conducted to define the molecular changes in each of the above major genomic categories in normal breast tissue considered to be either at normal risk or at high risk for sporadic breast cancer. This review indicates that normal risk breast tissues (such as reduction mammoplasty) contain evidence of early breast carcinogenesis including loss of heterozygosity, DNA methylation of tumor suppressor and other genes, and telomere shortening. In normal tissues at high risk for breast cancer (such as normal breast tissue adjacent to breast cancer or the contralateral breast), these changes persist, and are increased and accompanied by aneuploidy, increased genomic instability, a wide range of gene expression differences, development of large cancerized fields, and increased proliferation. These changes are consistent with early and long-standing exposure to carcinogens, especially estrogens. A model for the breast carcinogenic pathway in normal risk and high-risk breast tissues is proposed. These findings should clarify our understanding of breast carcinogenesis in normal breast tissue and promote development of improved methods for risk assessment and breast cancer prevention in women.
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Affiliation(s)
- David N Danforth
- Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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19
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Li Y, Zhu Y, Prochownik EV. MicroRNA-based screens for synthetic lethal interactions with c-Myc. RNA & DISEASE 2016; 3:e1330. [PMID: 27975083 PMCID: PMC5152767 DOI: 10.14800/rd.1330] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
microRNAs (miRs) are small, non-coding RNAs, which play crucial roles in the development and progression of human cancer. Given that miRs are stable, easy to synthetize and readily introduced into cells, they have been viewed as having potential therapeutic benefit in cancer. c-Myc (Myc) is one of the most commonly deregulated oncogenic transcription factors and has important roles in the pathogenesis of cancer, thus making it an important, albeit elusive therapeutic target. Here we review the miRs that have been identified as being both positive and negative targets for Myc and how these participate in the complex phenotypes that arise as a result of Myc-driven transformation. We also discussseveral recent reports of Myc-synthetic lethal interactions with miRs.These highlight the importance and complexity of miRs in Myc-mediated biological functions and the opportunities for Myc-driven human cancer therapies.
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Affiliation(s)
- Youjun Li
- College of Life Sciences, Wuhan University, Wuhan 430072, China
- Medical Research Institute, Wuhan University, Wuhan 430071, China
| | - Yahui Zhu
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Edward V. Prochownik
- Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC and The Department of Microbiology and Molecular Genetics, The University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15224, USA
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20
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Mundim FGL, Pasini FS, Brentani MM, Soares FA, Nonogaki S, Waitzberg AFL. MYC is expressed in the stromal and epithelial cells of primary breast carcinoma and paired nodal metastases. Mol Clin Oncol 2015; 3:506-514. [PMID: 26137258 DOI: 10.3892/mco.2015.526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 02/11/2015] [Indexed: 11/06/2022] Open
Abstract
The MYC oncogene is directly involved in the proliferation, metabolism, progression and distant metastasis of breast cancer. Since metastatic spread to the lymph nodes is often the first indication of propensity for metastatic dissemination, the MYC status in nodal disease may represent a decision-making variable. However, the analysis of MYC expression in stromal cells, namely cancer-associated fibroblasts (CAFs), which are known to play a critical role in cancer progression, remains poorly reported. The aim of this study was to determine the expression of MYC and other markers, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), p53, Ki67, epidermal growth factor receptor (EGFR), phosphorylated AKT (p-AKT) and phospho-mammalian target of rapamycin (p-mTOR) by immunohistochemistry in representative samples from 80 patients with ductal infiltrative breast cancer and 43 paired compromised axillary lymph nodes allocated in tissue microarrays (TMAs). The epithelial and stromal components of primary tumors and respective lymph node metastases were separately analyzed. MYC expression (cytoplasmic and nuclear) was a frequent event in the epithelial and stromal components of the primary tumors. The epithelial cells in the nodal metastases exhibited a trend for decreased MYC expression compared to that in the primary tumors (P=0.08) but retained the original status of the primary tumors for all other markers. The stromal cells were uniformly negative for ER, PR, HER2, p53, Ki67 and EGFR. Comparison of the stromas of primary tumors and respective lymph node metastases revealed a reduced frequency of nuclear MYC in 15% of the cases (P=0.003), whereas p-mTOR followed a similar trend (P=0.09). Analyses of the possible correlations among markers revealed that epithelial nuclear MYC was associated with p53 (P=0.048). This is an original study demonstrating a significant proportion of MYC expression (nuclear or cytoplasmic), as well p-mTOR and p-AKT expression, in the epithelial and stromal components of either the primary tumor or the nodal metastases. CAFs expressing MYC may establish an angiogenic microenvironment supporting cancer survival and facilitating colonization at the nodal metastatic site.
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Affiliation(s)
| | - Fatima Solange Pasini
- Department of Radiology and Oncology (LIM24), Medical School of São Paulo University, São Paulo, SP 01246-903, Brazil
| | - Maria Mitzi Brentani
- Department of Radiology and Oncology (LIM24), Medical School of São Paulo University, São Paulo, SP 01246-903, Brazil ; Department of Pathology, A.C. Camargo Hospital, São Paulo, SP 01509-010, Brazil
| | | | - Suely Nonogaki
- Department of Pathology, A.C. Camargo Hospital, São Paulo, SP 01509-010, Brazil
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21
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Wade MA, Sunter NJ, Fordham SE, Long A, Masic D, Russell LJ, Harrison CJ, Rand V, Elstob C, Bown N, Rowe D, Lowe C, Cuthbert G, Bennett S, Crosier S, Bacon CM, Onel K, Scott K, Scott D, Travis LB, May FEB, Allan JM. c-MYC is a radiosensitive locus in human breast cells. Oncogene 2014; 34:4985-94. [PMID: 25531321 PMCID: PMC4391966 DOI: 10.1038/onc.2014.427] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 10/15/2014] [Accepted: 11/21/2014] [Indexed: 12/30/2022]
Abstract
Ionising radiation is a potent human carcinogen. Epidemiological studies have shown that adolescent and young women are at increased risk of developing breast cancer following exposure to ionising radiation compared with older women, and that risk is dose-dependent. Although it is well understood which individuals are at risk of radiation-induced breast carcinogenesis, the molecular genetic mechanisms that underlie cell transformation are less clear. To identify genetic alterations potentially responsible for driving radiogenic breast transformation, we exposed the human breast epithelial cell line MCF-10A to fractionated doses of X-rays and examined the copy number and cytogenetic alterations. We identified numerous alterations of c-MYC that included high-level focal amplification associated with increased protein expression. c-MYC amplification was also observed in primary human mammary epithelial cells following exposure to radiation. We also demonstrate that the frequency and magnitude of c-MYC amplification and c-MYC protein expression is significantly higher in breast cancer with antecedent radiation exposure compared with breast cancer without a radiation aetiology. Our data also demonstrate extensive intratumor heterogeneity with respect to c-MYC copy number in radiogenic breast cancer, suggesting continuous evolution at this locus during disease development and progression. Taken together, these data identify c-MYC as a radiosensitive locus, implicating this oncogenic transcription factor in the aetiology of radiogenic breast cancer.
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Affiliation(s)
- M A Wade
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - N J Sunter
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - S E Fordham
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - A Long
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - D Masic
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - L J Russell
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - C J Harrison
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - V Rand
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - C Elstob
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - N Bown
- Northern Genetics Service, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - D Rowe
- Northern Genetics Service, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - C Lowe
- Northern Genetics Service, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - G Cuthbert
- Northern Genetics Service, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - S Bennett
- Northern Genetics Service, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - S Crosier
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - C M Bacon
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - K Onel
- Department of Pediatrics, University of Chicago, Chicago, IL, USA
| | - K Scott
- Department of Biology, University of York, Heslington, York, UK
| | - D Scott
- Department of Histopathology, Harrogate and District NHS Foundation Trust, Harrogate District Hospital, Yorkshire, UK
| | - L B Travis
- Department of Radiation Oncology and Rubin Center for Cancer Survivorship, James P Wilmot Cancer Center, University of Rochester Medical Center, Rochester, NY, USA
| | - F E B May
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - J M Allan
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
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22
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Maya-Mendoza A, Ostrakova J, Kosar M, Hall A, Duskova P, Mistrik M, Merchut-Maya JM, Hodny Z, Bartkova J, Christensen C, Bartek J. Myc and Ras oncogenes engage different energy metabolism programs and evoke distinct patterns of oxidative and DNA replication stress. Mol Oncol 2014; 9:601-16. [PMID: 25435281 PMCID: PMC5528704 DOI: 10.1016/j.molonc.2014.11.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 11/03/2014] [Accepted: 11/05/2014] [Indexed: 10/28/2022] Open
Abstract
Both Myc and Ras oncogenes impact cellular metabolism, deregulate redox homeostasis and trigger DNA replication stress (RS) that compromises genomic integrity. However, how are such oncogene-induced effects evoked and temporally related, to what extent are these kinetic parameters shared by Myc and Ras, and how are these cellular changes linked with oncogene-induced cellular senescence in different cell context(s) remain poorly understood. Here, we addressed the above-mentioned open questions by multifaceted comparative analyses of human cellular models with inducible expression of c-Myc and H-RasV12 (Ras), two commonly deregulated oncoproteins operating in a functionally connected signaling network. Our study of DNA replication parameters using the DNA fiber approach and time-course assessment of perturbations in glycolytic flux, oxygen consumption and production of reactive oxygen species (ROS) revealed the following results. First, overabundance of nuclear Myc triggered RS promptly, already after one day of Myc induction, causing slow replication fork progression and fork asymmetry, even before any metabolic changes occurred. In contrast, Ras overexpression initially induced a burst of cell proliferation and increased the speed of replication fork progression. However, after several days of induction Ras caused bioenergetic metabolic changes that correlated with slower DNA replication fork progression and the ensuing cell cycle arrest, gradually leading to senescence. Second, the observed oncogene-induced RS and metabolic alterations were cell-type/context dependent, as shown by comparative analyses of normal human BJ fibroblasts versus U2-OS sarcoma cells. Third, the energy metabolic reprogramming triggered by Ras was more robust compared to impact of Myc. Fourth, the detected oncogene-induced oxidative stress was due to ROS (superoxide) of non-mitochondrial origin and mitochondrial OXPHOS was reduced (Crabtree effect). Overall, our study provides novel insights into oncogene-evoked metabolic reprogramming, replication and oxidative stress, with implications for mechanisms of tumorigenesis and potential targeting of oncogene addiction.
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Affiliation(s)
| | - Jitka Ostrakova
- Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark
| | - Martin Kosar
- Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark; Department of Genome Integrity, Institute of Molecular Genetics, v.v.i., Academy of Sciences of the Czech Republic, CZ-142 20 Prague, Czech Republic
| | - Arnaldur Hall
- Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark
| | - Pavlina Duskova
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, CZ-775 15 Olomouc, Czech Republic
| | - Martin Mistrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, CZ-775 15 Olomouc, Czech Republic
| | | | - Zdenek Hodny
- Department of Genome Integrity, Institute of Molecular Genetics, v.v.i., Academy of Sciences of the Czech Republic, CZ-142 20 Prague, Czech Republic
| | - Jirina Bartkova
- Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark
| | | | - Jiri Bartek
- Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark; Department of Genome Integrity, Institute of Molecular Genetics, v.v.i., Academy of Sciences of the Czech Republic, CZ-142 20 Prague, Czech Republic; Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, CZ-775 15 Olomouc, Czech Republic.
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23
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Targeting c-MYC by antagonizing PP2A inhibitors in breast cancer. Proc Natl Acad Sci U S A 2014; 111:9157-62. [PMID: 24927563 DOI: 10.1073/pnas.1317630111] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The transcription factor c-MYC is stabilized and activated by phosphorylation at serine 62 (S62) in breast cancer. Protein phosphatase 2A (PP2A) is a critical negative regulator of c-MYC through its ability to dephosphorylate S62. By inactivating c-MYC and other key signaling pathways, PP2A plays an important tumor suppressor function. Two endogenous inhibitors of PP2A, I2PP2A, Inhibitor-2 of PP2A (SET oncoprotein) and cancerous inhibitor of PP2A (CIP2A), inactivate PP2A and are overexpressed in several tumor types. Here we show that SET is overexpressed in about 50-60% and CIP2A in about 90% of breast cancers. Knockdown of SET or CIP2A reduces the tumorigenic potential of breast cancer cell lines both in vitro and in vivo. Treatment of breast cancer cells in vitro or in vivo with OP449, a novel SET antagonist, also decreases the tumorigenic potential of breast cancer cells and induces apoptosis. We show that this is, at least in part, due to decreased S62 phosphorylation of c-MYC and reduced c-MYC activity and target gene expression. Because of the ubiquitous expression and tumor suppressor activity of PP2A in cells, as well as the critical role of c-MYC in human cancer, we propose that activation of PP2A (here accomplished through antagonizing endogenous inhibitors) could be a novel antitumor strategy to posttranslationally target c-MYC in breast cancer.
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Kang J, Sergio CM, Sutherland RL, Musgrove EA. Targeting cyclin-dependent kinase 1 (CDK1) but not CDK4/6 or CDK2 is selectively lethal to MYC-dependent human breast cancer cells. BMC Cancer 2014; 14:32. [PMID: 24444383 PMCID: PMC3903446 DOI: 10.1186/1471-2407-14-32] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 01/08/2014] [Indexed: 02/06/2023] Open
Abstract
Background Although MYC is an attractive therapeutic target for breast cancer treatment, it has proven challenging to inhibit MYC directly, and clinically effective pharmaceutical agents targeting MYC are not yet available. An alternative approach is to identify genes that are synthetically lethal in MYC-dependent cancer. Recent studies have identified several cell cycle kinases as MYC synthetic-lethal genes. We therefore investigated the therapeutic potential of specific cyclin-dependent kinase (CDK) inhibition in MYC-driven breast cancer. Methods Using small interfering RNA (siRNA), MYC expression was depleted in 26 human breast cancer cell lines and cell proliferation evaluated by BrdU incorporation. MYC-dependent and MYC-independent cell lines were classified based on their sensitivity to siRNA-mediated MYC knockdown. We then inhibited CDKs including CDK4/6, CDK2 and CDK1 individually using either RNAi or small molecule inhibitors, and compared sensitivity to CDK inhibition with MYC dependence in breast cancer cells. Results Breast cancer cells displayed a wide range of sensitivity to siRNA-mediated MYC knockdown. The sensitivity was correlated with MYC protein expression and MYC phosphorylation level. Sensitivity to siRNA-mediated MYC knockdown did not parallel sensitivity to the CDK4/6 inhibitor PD0332991; instead MYC-independent cell lines were generally sensitive to PD0332991. Cell cycle arrest induced by MYC knockdown was accompanied by a decrease in CDK2 activity, but inactivation of CDK2 did not selectively affect the viability of MYC-dependent breast cancer cells. In contrast, CDK1 inactivation significantly induced apoptosis and reduced viability of MYC-dependent cells but not MYC- independent cells. This selective induction of apoptosis by CDK1 inhibitors was associated with up-regulation of the pro-apoptotic molecule BIM and was p53-independent. Conclusions Overall, these results suggest that further investigation of CDK1 inhibition as a potential therapy for MYC-dependent breast cancer is warranted.
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Affiliation(s)
| | | | | | - Elizabeth A Musgrove
- The Kinghorn Cancer Centre and Cancer Research Division, Garvan Institute of Medical Research, 370 Victoria Street, Darlinghurst, Sydney, NSW, Australia.
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Wu JZ, Lu P, Liu R, Yang TJ. Transcription Regulation Network Analysis of MCF7 Breast Cancer Cells Exposed to Estradiol. Asian Pac J Cancer Prev 2012; 13:3681-5. [DOI: 10.7314/apjcp.2012.13.8.3681] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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A mouse model with T58A mutations in Myc reduces the dependence on KRas mutations and has similarities to claudin-low human breast cancer. Oncogene 2012; 32:1296-304. [DOI: 10.1038/onc.2012.142] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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27
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Ferguson RD, Novosyadlyy R, Fierz Y, Alikhani N, Sun H, Yakar S, LeRoith D. Hyperinsulinemia enhances c-Myc-mediated mammary tumor development and advances metastatic progression to the lung in a mouse model of type 2 diabetes. Breast Cancer Res 2012; 14:R8. [PMID: 22226054 PMCID: PMC3496123 DOI: 10.1186/bcr3089] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 10/31/2011] [Accepted: 01/07/2012] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Hyperinsulinemia, which is common in early type 2 diabetes (T2D) as a result of the chronically insulin-resistant state, has now been identified as a specific factor which can worsen breast cancer prognosis. In breast cancer, a high rate of mortality persists due to the emergence of pulmonary metastases. METHODS Using a hyperinsulinemic mouse model (MKR+/+) and the metastatic, c-Myc-transformed mammary carcinoma cell line Mvt1, we investigated how high systemic insulin levels would affect the progression of orthotopically inoculated primary mammary tumors to lung metastases. RESULTS We found that orthotopically injected Mvt1 cells gave rise to larger mammary tumors and to a significantly higher mean number of pulmonary macrometastases in hyperinsulinemic mice over a period of six weeks (hyperinsulinemic, 19.4 ± 2.7 vs. control, 4.0 ± 1.3). When Mvt1-mediated mammary tumors were allowed to develop and metastasize for approximately two weeks and were then surgically removed, hyperinsulinemic mice demonstrated a significantly higher number of lung metastases after a four-week period (hyperinsulinemic, 25.1 ± 4.6 vs. control, 7.4 ± 0.42). Similarly, when Mvt1 cells were injected intravenously, hyperinsulinemic mice demonstrated a significantly higher metastatic burden in the lung than controls after a three-week period (hyperinsulinemic, 6.0 ± 1.63 vs. control, 1.5 ± 0.68). Analysis of Mvt1 cells both in vitro and in vivo revealed a significant up-regulation of the transcription factor c-Myc under hyperinsulinemic conditions, suggesting that hyperinsulinemia may promote c-Myc signaling in breast cancer. Furthermore, insulin-lowering therapy using the beta-adrenergic receptor agonist CL-316243 reduced metastatic burden in hyperinsulinemic mice to control levels. CONCLUSIONS Hyperinsulinemia in a mouse model promotes breast cancer metastasis to the lung. Therapies to reduce insulin levels in hyperinsulinemic patients suffering from breast cancer could lessen the likelihood of metastatic progression.
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MESH Headings
- Animals
- Blood Glucose
- Cell Line, Tumor
- Cell Proliferation
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Dioxoles/pharmacology
- Dioxoles/therapeutic use
- Female
- Hyperinsulinism/complications
- Hyperinsulinism/drug therapy
- Hyperinsulinism/metabolism
- Hyperinsulinism/pathology
- Hypoglycemic Agents/pharmacology
- Hypoglycemic Agents/therapeutic use
- Insulin/blood
- Lung Neoplasms/metabolism
- Lung Neoplasms/prevention & control
- Lung Neoplasms/secondary
- Mammary Neoplasms, Experimental/etiology
- Mammary Neoplasms, Experimental/metabolism
- Mammary Neoplasms, Experimental/pathology
- Matrix Metalloproteinase 9/metabolism
- Mice
- Mice, Transgenic
- Neoplasm Transplantation
- Phosphorylation
- Proto-Oncogene Proteins c-akt/metabolism
- Proto-Oncogene Proteins c-myc/metabolism
- Receptor, IGF Type 1/metabolism
- Receptor, Insulin/metabolism
- Tumor Burden
- Vascular Endothelial Growth Factor A/metabolism
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Affiliation(s)
- Rosalyn D Ferguson
- Division of Endocrinology, Diabetes and Bone Diseases, The Samuel Bronfman Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Ruslan Novosyadlyy
- Division of Endocrinology, Diabetes and Bone Diseases, The Samuel Bronfman Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Yvonne Fierz
- Division of Endocrinology, Diabetes and Bone Diseases, The Samuel Bronfman Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Nyosha Alikhani
- Division of Endocrinology, Diabetes and Bone Diseases, The Samuel Bronfman Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Hui Sun
- Division of Endocrinology, Diabetes and Bone Diseases, The Samuel Bronfman Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Shoshana Yakar
- Division of Endocrinology, Diabetes and Bone Diseases, The Samuel Bronfman Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Derek LeRoith
- Division of Endocrinology, Diabetes and Bone Diseases, The Samuel Bronfman Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
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Abstract
MYC is a key regulator of cell growth, proliferation, metabolism, differentiation, and apoptosis. MYC deregulation contributes to breast cancer development and progression and is associated with poor outcomes. Multiple mechanisms are involved in MYC deregulation in breast cancer, including gene amplification, transcriptional regulation, and mRNA and protein stabilization, which correlate with loss of tumor suppressors and activation of oncogenic pathways. The heterogeneity in breast cancer is increasingly recognized. Breast cancer has been classified into 5 or more subtypes based on gene expression profiles, and each subtype has distinct biological features and clinical outcomes. Among these subtypes, basal-like tumor is associated with a poor prognosis and has a lack of therapeutic targets. MYC is overexpressed in the basal-like subtype and may serve as a target for this aggressive subtype of breast cancer. Tumor suppressor BRCA1 inhibits MYC's transcriptional and transforming activity. Loss of BRCA1 with MYC overexpression leads to the development of breast cancer-especially, basal-like breast cancer. As a downstream effector of estrogen receptor and epidermal growth factor receptor family pathways, MYC may contribute to resistance to adjuvant therapy. Targeting MYC-regulated pathways in combination with inhibitors of other oncogenic pathways may provide a promising therapeutic strategy for breast cancer, the basal-like subtype in particular.
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Affiliation(s)
- Jinhua Xu
- Center for Clinical Cancer Genetics, Department of Medicine, University of Chicago, Chicago, IL, USA
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29
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Palaskas N, Larson SM, Schultz N, Komisopoulou E, Wong J, Rohle D, Campos C, Yannuzzi N, Osborne JR, Linkov I, Kastenhuber ER, Taschereau R, Plaisier SB, Tran C, Heguy A, Wu H, Sander C, Phelps ME, Brennan C, Port E, Huse JT, Graeber TG, Mellinghoff IK. 18F-fluorodeoxy-glucose positron emission tomography marks MYC-overexpressing human basal-like breast cancers. Cancer Res 2011; 71:5164-74. [PMID: 21646475 DOI: 10.1158/0008-5472.can-10-4633] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In contrast to normal cells, cancer cells avidly take up glucose and metabolize it to lactate even when oxygen is abundant, a phenomenon referred to as the Warburg effect. This fundamental alteration in glucose metabolism in cancer cells enables their specific detection by positron emission tomography (PET) following i.v. injection of the glucose analogue (18)F-fluorodeoxy-glucose ((18)FDG). However, this useful imaging technique is limited by the fact that not all cancers avidly take up FDG. To identify molecular determinants of (18)FDG retention, we interrogated the transcriptomes of human-cancer cell lines and primary tumors for metabolic pathways associated with (18)FDG radiotracer uptake. From ninety-five metabolic pathways that were interrogated, the glycolysis, and several glycolysis-related pathways (pentose phosphate, carbon fixation, aminoacyl-tRNA biosynthesis, one-carbon-pool by folate) showed the greatest transcriptional enrichment. This "FDG signature" predicted FDG uptake in breast cancer cell lines and overlapped with established gene expression signatures for the "basal-like" breast cancer subtype and MYC-induced tumorigenesis in mice. Human breast cancers with nuclear MYC staining and high RNA expression of MYC target genes showed high (18)FDG-PET uptake (P < 0.005). Presence of the FDG signature was similarly associated with MYC gene copy gain, increased MYC transcript levels, and elevated expression of metabolic MYC target genes in a human breast cancer genomic dataset. Together, our findings link clinical observations of glucose uptake with a pathologic and molecular subtype of human breast cancer. Furthermore, they suggest related approaches to derive molecular determinants of radiotracer retention for other PET-imaging probes.
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Affiliation(s)
- Nicolaos Palaskas
- Crump Institute for Molecular Imaging, University of California, Los Angeles, CA, USA
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30
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Kim DY, Kim MJ, Kim HB, Lee JW, Bae JH, Kim DW, Kang CD, Kim SH. Suppression of multidrug resistance by treatment with TRAIL in human ovarian and breast cancer cells with high level of c-Myc. Biochim Biophys Acta Mol Basis Dis 2011; 1812:796-805. [PMID: 21514380 DOI: 10.1016/j.bbadis.2011.04.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 03/28/2011] [Accepted: 04/06/2011] [Indexed: 01/06/2023]
Abstract
In this study, we investigated the role of c-Myc in overcoming multidrug resistance (MDR) in human ovarian and breast cancer cells by TRAIL. We showed that P-gp expressing MDR variants (Hey A8-MDR and MCF7-MDR cells) with high level of c-Myc were highly susceptible to TRAIL treatment when compared to their drug-sensitive parental human ovarian cancer Hey A8 and breast MCF-7 cells, respectively. Up-regulation of DR5 TRAIL receptor and down-regulation of c-FLIP and the promotion of caspase-dependent cell death, which contribute to TRAIL sensitization of MDR cells, were regulated by the over-expressed c-Myc in the MDR cells. After targeted inhibition of c-Myc with specific siRNA, these responses to TRAIL disappeared and TRAIL-induced apoptosis was also suppressed in MCF7-MDR cells. Treatment with TRAIL significantly reduced P-glycoprotein (P-gp)-mediated efflux of rhodamine123 in both Hey A8-MDR and MCF7-MDR cells. Furthermore, TRAIL significantly potentiated the cytotoxicity of vinblastine, vincristine, doxorubicin and VP-16 that are P-gp substrate anticancer drugs in both MDR cells, which resulted in the reversal effect of TRAIL on the MDR phenotype. The present study shows for the first time that elevated c-Myc expression in the MDR cells plays a critical role in overcoming MDR by TRAIL that can act as a specific sensitizer for P-gp substrate anticancer drug.
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Affiliation(s)
- Dae-Young Kim
- Department of Biochemistry, Pusan National University School of Medicine, Yangsan 626-870, South Korea
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Wang X, Cunningham M, Zhang X, Tokarz S, Laraway B, Troxell M, Sears RC. Phosphorylation regulates c-Myc's oncogenic activity in the mammary gland. Cancer Res 2011; 71:925-36. [PMID: 21266350 DOI: 10.1158/0008-5472.can-10-1032] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Expression of the c-Myc oncoprotein is affected by conserved threonine 58 (T58) and serine 62 (S62) phosphorylation sites that help to regulate c-Myc protein stability, and altered ratios of T58 and S62 phosphorylation have been observed in human cancer. Here, we report the development of 3 unique c-myc knock-in mice that conditionally express either c-Myc(WT) or the c-Myc(T58A) or c-Myc(S62A) phosphorylation mutant from the constitutively active ROSA26 locus in response to Cre recombinase to study the role of these phosphorylation sites in vivo. Using a mammary-specific Cre model, we found that expression of c-Myc(WT) resulted in increased mammary gland density, but normal morphology and no tumors at the level expressed from the ROSA promoter. In contrast, c-Myc(T58A) expression yielded enhanced mammary gland density, hyperplastic foci, cellular dysplasia, and mammary carcinoma, associated with increased genomic instability and suppressed apoptosis relative to c-Myc(WT). Alternatively, c-Myc(S62A) expression reduced mammary gland density relative to control glands, and this was associated with increased genomic instability and normal apoptotic function. Our results indicate that specific activities of c-Myc are differentially affected by T58 and S62 phosphorylation. This model provides a robust platform to interrogate the role that these phosphorylation sites play in c-Myc function during development and tumorigenesis.
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Affiliation(s)
- Xiaoyan Wang
- Molecular and Medical Genetics Department, Oregon Health and Sciences University, Portland, Oregon, USA
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32
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Zeng X, Shaikh FY, Harrison MK, Adon AM, Trimboli AJ, Carroll KA, Sharma N, Timmers C, Chodosh LA, Leone G, Saavedra HI. The Ras oncogene signals centrosome amplification in mammary epithelial cells through cyclin D1/Cdk4 and Nek2. Oncogene 2010; 29:5103-12. [PMID: 20581865 DOI: 10.1038/onc.2010.253] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Centrosome amplification (CA) contributes to carcinogenesis by generating aneuploidy. Elevated frequencies of CA in most benign breast lesions and primary tumors suggest a causative role for CA in breast cancers. Clearly, identifying which and how altered signal transduction pathways contribute to CA is crucial to breast cancer control. Although a causative and cooperative role for c-Myc and Ras in mammary tumorigenesis is well documented, their ability to generate CA during mammary tumor initiation remains unexplored. To answer that question, K-Ras(G12D) and c-Myc were induced in mouse mammary glands. Although CA was observed in mammary tumors initiated by c-Myc or K-Ras(G12D), it was detected only in premalignant mammary lesions expressing K-Ras(G12D). CA, both in vivo and in vitro, was associated with increased expression of the centrosome-regulatory proteins, cyclin D1 and Nek2. Abolishing the expression of cyclin D1, Cdk4 or Nek2 in MCF10A human mammary epithelial cells expressing H-Ras(G12V) abrogated Ras-induced CA, whereas silencing cyclin E1 or B2 had no effect. Thus, we conclude that CA precedes mammary tumorigenesis, and interfering with centrosome-regulatory targets suppresses CA.
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Affiliation(s)
- X Zeng
- Department of Radiation Oncology, Emory University School of Medicine, and Emory Winship Cancer Institute, Atlanta, GA 30322, USA
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Côme C, Laine A, Chanrion M, Edgren H, Mattila E, Liu X, Jonkers J, Ivaska J, Isola J, Darbon JM, Kallioniemi O, Thézenas S, Westermarck J. CIP2A is associated with human breast cancer aggressivity. Clin Cancer Res 2009; 15:5092-100. [PMID: 19671842 DOI: 10.1158/1078-0432.ccr-08-3283] [Citation(s) in RCA: 187] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To investigate the clinical relevance of the recently characterized human oncoprotein cancerous inhibitor of protein phosphatase 2A (CIP2A) in human breast cancer. EXPERIMENTAL DESIGN CIP2A expression (mRNA and protein) was measured in three different sets of human mammary tumors and compared with clinicopathologic variables. The functional role of CIP2A in breast cancer cells was evaluated by small interfering RNA-mediated depletion of the protein followed by an analysis of cell proliferation, migration, anchorage-independent growth, and xenograft growth. RESULTS CIP2A mRNA is overexpressed (n = 159) and correlates with higher Scarff-Bloom-Richardson grades (n = 251) in samples from two independent human breast cancer patients. CIP2A protein was found to be overexpressed in 39% of 33 human breast cancer samples. Furthermore, CIP2A mRNA expression positively correlated with lymph node positivity of the patients and with the expression of proliferation markers and p53 mutations in the tumor samples. Moreover, CIP2A protein expression was induced in breast cancer mouse models presenting mammary gland-specific depletion of p53 and either BRCA1 or BRCA2. Functionally, CIP2A depletion was shown to inhibit the expression of its target protein c-Myc. Loss of CIP2A also inhibited anchorage-independent growth in breast cancer cells. Finally, CIP2A was shown to support MDA-MB-231 xenograft growth in nude mice. CONCLUSIONS Our data show that CIP2A is associated with clinical aggressivity in human breast cancer and promotes the malignant growth of breast cancer cells. Thus, these results validate the role of CIP2A as a clinically relevant human oncoprotein and warrant further investigation of CIP2A as a therapeutic target in breast cancer treatment.
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Affiliation(s)
- Christophe Côme
- Centre for Biotechnology, University of Turku, Turku, Finland
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Abstract
Breast cancer is the second leading cause of cancer deaths and is the most frequently diagnosed cancer in women of industrialized nations. Breast cancer progression is a multistep process involving genetic and epigenetic alterations that drive normal breast cells into highly malignant derivatives with metastatic potential. MYC is a proto-oncogene whose protein product contains a basic helix-loop-helix domain. MYC functions as a transcription factor regulating up to 15% of all human genes. MYC is regulated at multiple levels, and the protein is a downstream effector of several signaling pathways. In breast cancer cells, MYC target genes are involved in cell growth, transformation, angiogenesis and cell-cycle control. BRCA1 is linked to transcriptional regulation through interaction with MYC. Although the relationship between amplification and overexpression is not clearly delineated, MYC amplification is significantly correlated with aggressive tumor phenotypes and poor clinical outcomes. MYC amplification is emerging as an important predictor of response to HER2-targeted therapies and its role in BRCA1-associated breast cancer makes it an important target in basal-like/triple-negative breast cancers.
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Affiliation(s)
- Yinghua Chen
- Department of Medicine, Center for Clinical Cancer Genetics, University of Chicago, Chicago, IL 60637, USA.
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35
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An J, Yang DY, Xu QZ, Zhang SM, Huo YY, Shang ZF, Wang Y, Wu DC, Zhou PK. DNA-dependent protein kinase catalytic subunit modulates the stability of c-Myc oncoprotein. Mol Cancer 2008; 7:32. [PMID: 18426604 PMCID: PMC2383926 DOI: 10.1186/1476-4598-7-32] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Accepted: 04/22/2008] [Indexed: 12/31/2022] Open
Abstract
Background C-Myc is a short-lived oncoprotein that is destroyed by ubiquitin-mediated proteolysis. Dysregulated accumulation of c-Myc commonly occurs in human cancers. Some of those cases with the dysregulated c-Myc protein accumulation are attributed to gene amplification or increased mRNA expression. However, the abnormal accumulation of c-Myc protein is also a common finding in human cancers with normal copy number and transcription level of c-Myc gene. It seems that the mechanistic dysregulation in the control of c-Myc protein stabilization is another important hallmark associated with c-Myc accumulation in cancer cells. Here we report a novel mechanistic pathway through which DNA-dependent protein kinase catalytic subunit (DNA-PKcs) modulates the stability of c-Myc protein. Results Firstly, siRNA-mediated silencing of DNA-PKcs strikingly downregulated c-Myc protein levels in HeLa and HepG2 cells, and simultaneously decreased cell proliferation. The c-Myc protein level in DNA-PKcs deficient human glioma M059J cells was also found much lower than that in DNA-PKcs efficient M059K cells. ATM deficiency does not affect c-Myc expression level. Silencing of DNA-PKcs in HeLa cells resulted in a decreased stability of c-Myc protein, which was associated the increasing of c-Myc phosphorylation on Thr58/Ser62 and ubiquitination level. Phosphorylation of Akt on Ser473, a substrate of DNA-PKcs was found decreased in DNA-PKcs deficient cells. As the consequence, the phosphorylation of GSK3 β on Ser9, a negatively regulated target of Akt, was also decreased, and which led to activation of GSK 3β and in turn phosphorylation of c-Myc on Thr58. Moreover, inhibition of GSK3 activity by LiCl or specific siRNA molecules rescued the downregulation of c-Myc mediated by silencing DNA-PKcs. Consistent with this depressed DNA-PKcs cell model, overexpressing DNA-PKcs in normal human liver L02 cells, by sub-chronically exposing to very low dose of carcinogen 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), increased c-Myc protein level, the phosphorylation of Akt and GSK3 β, as well as cell proliferation. siRNA-mediated silencing of DNA-PKcs in this cell model reversed above alterations to the original levels of L02 cells. Conclusion A suitable DNA-PKcs level in cells is necessary for maintaining genomic stability, while abnormal overexpression of DNA-PKcs may contribute to cell proliferation and even oncogenic transformation by stabilizing the c-Myc oncoprotein via at least the Akt/GSK3 pathway. Our results suggest DNA-PKcs a novel biological role beyond its DNA repair function.
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Affiliation(s)
- Jing An
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, Beijing, 100850, PR China.
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Ordway JM, Budiman MA, Korshunova Y, Maloney RK, Bedell JA, Citek RW, Bacher B, Peterson S, Rohlfing T, Hall J, Brown R, Lakey N, Doerge RW, Martienssen RA, Leon J, McPherson JD, Jeddeloh JA. Identification of novel high-frequency DNA methylation changes in breast cancer. PLoS One 2007; 2:e1314. [PMID: 18091988 PMCID: PMC2117343 DOI: 10.1371/journal.pone.0001314] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 11/06/2007] [Indexed: 12/31/2022] Open
Abstract
Recent data have revealed that epigenetic alterations, including DNA methylation and chromatin structure changes, are among the earliest molecular abnormalities to occur during tumorigenesis. The inherent thermodynamic stability of cytosine methylation and the apparent high specificity of the alterations for disease may accelerate the development of powerful molecular diagnostics for cancer. We report a genome-wide analysis of DNA methylation alterations in breast cancer. The approach efficiently identified a large collection of novel differentially DNA methylated loci (∼200), a subset of which was independently validated across a panel of over 230 clinical samples. The differential cytosine methylation events were independent of patient age, tumor stage, estrogen receptor status or family history of breast cancer. The power of the global approach for discovery is underscored by the identification of a single differentially methylated locus, associated with the GHSR gene, capable of distinguishing infiltrating ductal breast carcinoma from normal and benign breast tissues with a sensitivity and specificity of 90% and 96%, respectively. Notably, the frequency of these molecular abnormalities in breast tumors substantially exceeds the frequency of any other single genetic or epigenetic change reported to date. The discovery of over 50 novel DNA methylation-based biomarkers of breast cancer may provide new routes for development of DNA methylation-based diagnostics and prognostics, as well as reveal epigenetically regulated mechanism involved in breast tumorigenesis.
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Affiliation(s)
- Jared M Ordway
- Orion Genomics, St. Louis, Missouri, United States of America.
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Comtesse N, Keller A, Diesinger I, Bauer C, Kayser K, Huwer H, Lenhof HP, Meese E. Frequent overexpression of the genes FXR1, CLAPM1 and EIF4G located on amplicon 3q26-27 in squamous cell carcinoma of the lung. Int J Cancer 2007; 120:2538-44. [PMID: 17290396 DOI: 10.1002/ijc.22585] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Previously, we reported gene amplification at chromosome 3q26-27 in more than one third of squamous cell carcinomas of the lung. Frequent amplification of eukaryotic translation initiation factor 4G on 3q27.1 indicated a possible role of this amplification in translation initiation. The analysis of 61 squamous cell lung carcinomas shows that the percentage of carcinomas with a 3q27.1 amplification increases in higher malignant tumors. Non-invasive (T1) and minimal-invasive (T2) tumor stages showed similar percentages of amplified and non-amplified tumors, whereas locally-invasive (T3) tumors revealed a statistically significant (p < 0.05) increased percentage of amplified tumors. Microarrays were used to analyze the expression pattern of genes mapping in the amplified domain and its flanking regions (3q25-28) as well as the expression of genes directly or indirectly associated with translation initiation in squamous cell carcinoma, large cell carcinoma, adenocarcinoma and small cell carcinoma. Three genes, namely FXR1, CLAPM1 and EIF4G, are most frequently overexpressed in the center of the amplified domain in squamous cell carcinomas. The eukaryotic translation initiation factors 4A1, 2B and 4B as well as the poly(A)-binding protein PABPC1 where found to be overexpressed in all lung cancer entities. We found, however, no overexpression of eIF4E. Our results contribute to the understanding of the frequent amplification processes in squamous cell carcinomas of the lung and to the understanding of the translation initiation that appears not to require eIF4E in lung carcinogenesis.
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Affiliation(s)
- Nicole Comtesse
- Department of Human Genetics, Medical School, Saarland University, Homburg, Germany
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38
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Abstract
AbstractBreast cancer is one of the most frequently diagnosed cancers among women in the western world. Due to the aggressive behaviour of some specific types and the possibility of an early diagnosis, breast cancer has been constantly studied. Tumour size, histological type, cellular and nuclear characteristics, mitotic index, vascular invasion, hormonal receptors and axillary lymph node status are biomarkers routinely used. However, these parameters are not enough to predict the course of this disease. Molecular biology advances have made it possible to find new markers, which have already been incorporated to the clinical practice. Their ultimate goal is to reduce mortality by identifying women at risk for the development of this disease, help diagnosis, determine prognosis, detect recurrences, monitor and guide treatment, and in particular cancers they are suited for general screening. Tumour markers in breast cancer were ranked in categories reflecting their clinical utility, according to the American College of Pathologists.This article focuses on traditional and new molecular markers stratifying them into categories and emphasizing their relevance in the routine evaluation of patients with breast cancer.
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39
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McNeil CM, Sergio CM, Anderson LR, Inman CK, Eggleton SA, Murphy NC, Millar EKA, Crea P, Kench JG, Alles MC, Gardiner-Garden M, Ormandy CJ, Butt AJ, Henshall SM, Musgrove EA, Sutherland RL. c-Myc overexpression and endocrine resistance in breast cancer. J Steroid Biochem Mol Biol 2006; 102:147-55. [PMID: 17052904 DOI: 10.1016/j.jsbmb.2006.09.028] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The oncoprotein c-Myc is frequently overexpressed in breast cancer and ectopic expression in breast cancer cell lines attenuates responses to antiestrogen treatment. Here, we review preliminary data aimed at further elucidating a potential role for c-Myc in clinical endocrine resistance in breast cancer. Immunohistochemical and semi-quantitative PCR revealed that c-Myc protein and c-myc mRNA were frequently overexpressed in both ER-positive and ER-negative breast carcinoma. Furthermore, both constitutive and inducible c-Myc overexpression in MCF-7 breast cancer cell lines markedly reduced their sensitivity to the growth inhibitory effects of the pure antiestrogen ICI 182,780. In order to identify potential downstream targets of c-Myc that mediate this effect, Affymetrix microarrays were employed to examine the patterns of gene expression shared by MCF-7 cells stimulated by estrogen, or by induction of c-Myc. Approximately 50% of estrogen target genes identified 6h after treatment were also regulated by c-Myc. One novel target, EMU4, was transcriptionally regulated by c-Myc. In addition, there was a strong correlation between c-myc and EMU4 mRNA expression in a battery of breast cancer cell lines. These data confirm that c-Myc overexpression is a common event in breast cancer, and that this is associated with resistance to antiestrogens in vitro. Furthermore, the development of an experimental paradigm for the discovery of c-Myc and estrogen target genes associated with endocrine resistance provides a framework for the discovery and validation of genes involved in estrogen signalling, and c-Myc-mediated-antiestrogen resistance.
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Affiliation(s)
- Catriona M McNeil
- Cancer Research Program, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010, Australia
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40
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Abstract
Myc expression is deregulated in a wide range of human cancers and is often associated with aggressive, poorly differentiated tumors. The Myc protein is a transcription factor that regulates a variety of cellular processes including cell growth and proliferation, cell-cycle progression, transcription, differentiation, apoptosis, and cell motility. Potential strategies that either inhibit the growth promoting effect of Myc and/or activate its pro-apoptotic function are presently being explored. In this review, we give an overview of Myc activation in human tumors and discuss current strategies aimed at targeting Myc for cancer treatment. Such therapies could have potential in combination with mechanistically different cytotoxic drugs to combat and eradicate tumors cells.
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Affiliation(s)
- Marina Vita
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
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41
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Shervington A, Cruickshanks N, Wright H, Atkinson-Dell R, Lea R, Roberts G, Shervington L. Glioma: What is the role of c-Myc, hsp90 and telomerase? Mol Cell Biochem 2006; 283:1-9. [PMID: 16444580 DOI: 10.1007/s11010-006-2495-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Accepted: 08/26/2005] [Indexed: 01/24/2023]
Abstract
The continuous advancements in cancer research have contributed to the overwhelming evidence of the presence of telomerase in primary and secondary tumours together with hsp90 and c-Myc. This review will discuss the important role of telomerase together with hsp90 and c-Myc within the initiation and progression of gliomas. Also it will review the differential expression of these genes in the different grades of gliomas and the possibility of new treatments targeting these specific genes.
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Affiliation(s)
- A Shervington
- Department of Biological Sciences, University of Central Lancashire, Preston, UK.
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42
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Yeh ES, Lew BO, Means AR. The loss of PIN1 deregulates cyclin E and sensitizes mouse embryo fibroblasts to genomic instability. J Biol Chem 2005; 281:241-51. [PMID: 16223725 DOI: 10.1074/jbc.m505770200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
During the G0/G1-S phase transition, the timely synthesis and degradation of key regulatory proteins is required for normal cell cycle progression. Two of these proteins, c-Myc and cyclin E, are recognized by the Cdc4 E3 ligase of the Skp1/Cul1/Rbx1 (SCF) complex. SCF(Cdc4) binds to a similar phosphodegron sequence in c-Myc and cyclin E proteins resulting in ubiquitylation and degradation of both proteins via the 26 S proteosome. Since the prolyl isomerase Pin1 binds the c-Myc phosphodegron and participates in regulation of c-Myc turnover, we hypothesized that Pin1 would bind to and regulate cyclin E turnover in a similar manner. Here we show that Pin1 regulates the turnover of cyclin E in mouse embryo fibroblasts. Pin1 binds to the cyclin E-Cdk2 complex in a manner that depends on Ser384 of cyclin E, which is phosphorylated by Cdk2. The absence of Pin1 results in an increased steady-state level of cyclin E and stalling of the cells in the G1/S phase of the cell cycle. The cellular changes that result from the loss of Pin1 predispose Pin1 null mouse embryo fibroblasts to undergo more rapid genomic instability when immortalized by conditional inactivation of p53 and sensitizes these cells to more aggressive Ras-dependent transformation and tumorigenesis.
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Affiliation(s)
- Elizabeth S Yeh
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710-3813, USA
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43
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Blakely CM, Sintasath L, D'Cruz CM, Hahn KT, Dugan KD, Belka GK, Chodosh LA. Developmental stage determines the effects of MYC in the mammary epithelium. Development 2005; 132:1147-60. [PMID: 15689376 DOI: 10.1242/dev.01655] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Epidemiological findings suggest that the consequences of a given oncogenic stimulus vary depending upon the developmental state of the target tissue at the time of exposure. This is particularly evident in the mammary gland, where both age at exposure to a carcinogenic stimulus and the timing of a first full-term pregnancy can markedly alter the risk of developing breast cancer. Analogous to this, the biological consequences of activating oncogenes, such as MYC, can be influenced by cellular context both in terms of cell lineage and cellular environment. In light of this, we hypothesized that the consequences of aberrant MYC activation in the mammary gland might be determined by the developmental state of the gland at the time of MYC exposure. To test this hypothesis directly, we have used a doxycycline-inducible transgenic mouse model to overexpress MYC during different stages of mammary gland development. Using this model, we find that the ability of MYC to inhibit postpartum lactation is due entirely to its activation within a specific 72-hour window during mid-pregnancy; by contrast, MYC activation either prior to or following this 72-hour window has little or no effect on postpartum lactation. Surprisingly, we find that MYC does not block postpartum lactation by inhibiting mammary epithelial differentiation, but rather by promoting differentiation and precocious lactation during pregnancy, which in turn leads to premature involution of the gland. We further show that this developmental stage-specific ability of MYC to promote mammary epithelial differentiation is tightly linked to its ability to downregulate caveolin 1 and activate Stat5 in a developmental stage-specific manner. Our findings provide unique in vivo molecular evidence for developmental stage-specific effects of oncogene activation, as well as the first evidence linking MYC with activation of the Jak2-Stat5 signaling pathway.
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Affiliation(s)
- Collin M Blakely
- Departments of Cancer Biology, Cell and Developmental Biology, Medicine, and The Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6160, USA
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44
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Zhang H, Yi X, Sun X, Yin N, Shi B, Wu H, Wang D, Wu G, Shang Y. Differential gene regulation by the SRC family of coactivators. Genes Dev 2004; 18:1753-65. [PMID: 15256502 PMCID: PMC478195 DOI: 10.1101/gad.1194704] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
SRCs (steroid receptor coactivators) are required for nuclear receptor-mediated transcription and are also implicated in the transcription initiation by other transcription factors, such as STATs and NFkappaB. Despite phenotypic manifestations in gene knockout mice for SRC-1, GRIP1, and AIB1 of the SRC (Steroid Receptor Coactivator) family indicating their differential roles in animal physiology, there is no clear evidence, at the molecular level, to support a functional specificity for these proteins. We demonstrated in this report that two species of SRC coactivators, either as AIB1:GRIP1 or as AIB1:SRC-1 are recruited, possibly through heterodimerization, on the promoter of genes that contain a classical hormone responsive element (HRE). In contrast, on non-HRE-containing gene promoters, on which steroid receptors bind indirectly, either GRIP1 or SRC-1 is recruited as a monomer, depending on the cellular abundance of the protein. Typically, non-HRE-containing genes are early genes activated by steroid receptors, whereas HRE-containing genes are activated later. Our results also showed that SRC proteins contribute to the temporal regulation of gene transcription. In addition, our experiments revealed a positive correlation between AIB1/c-myc overexpression in ER+ breast carcinoma samples, suggesting a possible mechanism for AIB1 in breast cancer carcinogenesis.
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Affiliation(s)
- Hua Zhang
- Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100083, China
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45
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Ray ME, Yang ZQ, Albertson D, Kleer CG, Washburn JG, Macoska JA, Ethier SP. Genomic and Expression Analysis of the 8p11–12 Amplicon in Human Breast Cancer Cell Lines. Cancer Res 2004; 64:40-7. [PMID: 14729606 DOI: 10.1158/0008-5472.can-03-1022] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Gene amplification is an important mechanism of oncogene activation in breast and other cancers. Characterization of amplified regions of the genome in breast cancer has led to the identification of important oncogenes including erbB-2/HER-2, C-MYC, and fibroblast growth factor receptor (FGFR) 2. Chromosome 8p11-p12 is amplified in 10-15% of human breast cancers. The putative oncogene FGFR1 localizes to this region; however, we show evidence that FGFR inhibition fails to slow growth of three breast cancer cell lines with 8p11-p12 amplification. We present a detailed analysis of this amplicon in three human breast cancer cell lines using comparative genomic hybridization, traditional Southern and Northern analysis, and chromosome 8 cDNA microarray expression profiling. This study has identified new candidate oncogenes within the 8p11-p12 region, supporting the hypothesis that genes other than FGFR1 may contribute to oncogenesis in breast cancers with proximal 8p amplification.
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Affiliation(s)
- Michael E Ray
- Department of Radiation Oncology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0948, USA
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46
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Cozma D, Lukes L, Rouse J, Qiu TH, Liu ET, Hunter KW. A bioinformatics-based strategy identifies c-Myc and Cdc25A as candidates for the Apmt mammary tumor latency modifiers. Genome Res 2002; 12:969-75. [PMID: 12045150 PMCID: PMC1383737 DOI: 10.1101/gr.210502] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The epistatically interacting modifier loci (Apmt1 and Apmt2) accelerate the polyoma Middle-T (PyVT)-induced mammary tumor. To identify potential candidate genes loci, a combined bioinformatics and genomics strategy was used. On the basis of the assumption that the loci were functioning in the same or intersecting pathways, a search of the literature databases was performed to identify molecular pathways containing genes from both candidate intervals. Among the genes identified by this method were the cell cycle-associated genes Cdc25A and c-Myc, both of which have been implicated in breast cancer. Genomic sequencing revealed noncoding polymorphism in both genes, in the promoter region of Cdc25A, and in the 3' UTR of c-Myc. Molecular and in vitro analysis showed that the polymorphisms were functionally significant. In vivo analysis was performed by generating compound PyVT/Myc double-transgenic animals to mimic the hypothetical model, and was found to recapitulate the age-of-onset phenotype. These data suggest that c-Myc and Cdc25A are Apmt1 and Apmt2, and suggest that, at least in certain instances, bioinformatics can be utilized to bypass congenic construction and subsequent mapping in conventional QTL studies.
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Affiliation(s)
- Diana Cozma
- Laboratory of Population Genetics, Medicine Branch, Center for Cancer Research, National Cancer Institute/National Institutes of Health, Bethesda, MD 20892, USA
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47
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Napoli C, Lerman LO, de Nigris F, Sica V. c-Myc oncoprotein: a dual pathogenic role in neoplasia and cardiovascular diseases? Neoplasia 2002; 4:185-90. [PMID: 11988837 PMCID: PMC1531691 DOI: 10.1038/sj.neo.7900232] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2001] [Accepted: 11/21/2001] [Indexed: 12/17/2022]
Abstract
A growing body of evidence indicates that c-Myc can play a pivotal role both in neoplasia and cardiovascular diseases. Indeed, alterations of the basal machinery of the cell and perturbations of c-Myc-dependent signaling network are involved in the pathogenesis of certain cardiovascular disorders. Down-regulation of c-Myc induced by intervention with antioxidants or by antisense technology may protect the integrity of the arterial wall as well as neoplastic tissues. Further intervention studies are necessary to investigate the effects of tissue-specific block of c-Myc overexpression in the development of cardiovascular diseases.
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Affiliation(s)
- Claudio Napoli
- Department of Medicine, University of California at San Diego, 9500 Gilman Drive, San Diego, CA 92093, USA.
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