1
|
Kim MS, Gernapudi R, Choi EY, Lapidus RG, Passaniti A. Characterization of CADD522, a small molecule that inhibits RUNX2-DNA binding and exhibits antitumor activity. Oncotarget 2017; 8:70916-70940. [PMID: 29050333 PMCID: PMC5642608 DOI: 10.18632/oncotarget.20200] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/12/2017] [Indexed: 12/29/2022] Open
Abstract
The RUNX2 transcription factor promotes breast cancer growth and metastasis through interactions with a variety of cofactors that activate or repress target genes. Using a direct drug discovery approach we identified CADD522 as a small molecule that inhibits the DNA binding of the runt box domain protein, RUNX2. The current study defines the effect of CADD522 on breast cancer growth and metastasis, and addresses the mechanisms by which it exerts its anti-tumor activity. CADD522 treatment resulted in significant growth inhibition, clonogenic survival, tumorsphere formation, and invasion of breast cancer cells. CADD522 negatively regulated transcription of RUNX2 target genes such as matrix metalloproteinase-13, vascular endothelial growth factor and glucose transporter-1, but upregulated RUNX2 expression by increasing RUNX2 stability. CADD522 reduced RUNX2-mediated increases in glucose uptake and decreased the level of CBF-β and RUNX2 phosphorylation at the S451 residue. These results suggest several potential mechanisms by which CADD522 exerts an inhibitory function on RUNX2-DNA binding; interference with RUNX2 for the DNA binding pocket, inhibition of glucose uptake leading to cell cycle arrest, down-regulation of CBF-β, and reduction of S451-RUNX2 phosphorylation. The administration of CADD522 into MMTV-PyMT mice resulted in significant delay in tumor incidence and reduction in tumor burden. A significant decrease of tumor volume was also observed in a CADD522-treated human triple-negative breast cancer-patient derived xenograft model. CADD522 impaired the lung retention and outgrowth of breast cancer cells in vivo with no apparent toxicity to the mice. Therefore, by inhibiting RUNX2-DNA binding, CADD522 may represent a potential antitumor drug.
Collapse
Affiliation(s)
- Myoung Sook Kim
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA.,The Marlene & Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.,The Veteran's Health Administration Research & Development Service, Baltimore, MD, USA
| | - Ramkishore Gernapudi
- Department of Biochemistry & Molecular Biology and Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.,The Marlene & Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Eun Yong Choi
- The Marlene & Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Rena G Lapidus
- The Marlene & Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Antonino Passaniti
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Biochemistry & Molecular Biology and Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.,The Marlene & Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.,The Veteran's Health Administration Research & Development Service, Baltimore, MD, USA
| |
Collapse
|
2
|
Merkel cell polyomavirus in Merkel cell carcinogenesis: small T antigen-mediates c-Jun phosphorylation. Virus Genes 2016; 52:397-9. [DOI: 10.1007/s11262-016-1304-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/16/2016] [Indexed: 10/22/2022]
|
3
|
Lee CJ, Jang JH, Lee JY, Lee MH, Li Y, Ryu HW, Choi KI, Dong Z, Lee HS, Oh SR, Surh YJ, Cho YY. Aschantin targeting on the kinase domain of mammalian target of rapamycin suppresses epidermal growth factor-induced neoplastic cell transformation. Carcinogenesis 2015; 36:1223-34. [PMID: 26243309 DOI: 10.1093/carcin/bgv113] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 07/27/2015] [Indexed: 12/22/2022] Open
Abstract
Mammalian target of rapamycin (mTOR), a serine/threonine protein kinase, forms two different complexes, complex 1 and 2, and plays a key role in the regulation of Akt signaling-mediated cell proliferation and transformation. This study reveals aschantin, a natural compound abundantly found in Magnolia flos, as a novel mTOR kinase inhibitor. Aschantin directly targeted the active pocket of mTOR kinase domain by competing with adenosine triphosphate (ATP), but not PI3K and PDK1. Aschantin inhibited epidermal growth factor (EGF)-induced full activation of Akt by phosphorylation at Ser473/Thr308, resulting in inhibition of the mTORC2/Akt and Akt/mTORC1/p70S6K signaling pathways and activation of GSK3β by abrogation of Akt-mediated GSK3β phosphorylation at Ser9. The activated GSK3β inhibited cell proliferation by c-Jun phosphorylation at Ser243, which facilitated destabilization and degradation of c-Jun through the ubiquitination-mediated proteasomal degradation pathway. Notably, aschantin treatment decreased c-Jun stability through inhibition of the mTORC2-Akt signaling pathway, which suppressed EGF-induced anchorage-independent cell transformation in non-malignant JB6 Cl41 and HaCaT cells and colony growth of LNCaP and MIAPaCa-2 cancer cells in soft agar. Altogether, the results show that aschantin targets mTOR kinase and destabilizes c-Jun, which implicate aschantin as a potential chemopreventive or therapeutic agent.
Collapse
Affiliation(s)
- Cheol-Jung Lee
- College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743, Republic of Korea
| | - Jeong-Hoon Jang
- College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743, Republic of Korea, College of Pharmacy, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Ji-Young Lee
- College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743, Republic of Korea
| | - Mee-Hyun Lee
- College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743, Republic of Korea
| | - Yan Li
- The Hormel Institute, University of Minnesota, 801, 16th AVE, NE, Austin, MN 55912, USA and
| | - Hyung Won Ryu
- Natural Medicine Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gun, ChungBuk 363-883, Republic of Korea
| | - Kyung-Il Choi
- College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743, Republic of Korea
| | - Zigang Dong
- The Hormel Institute, University of Minnesota, 801, 16th AVE, NE, Austin, MN 55912, USA and
| | - Hye Suk Lee
- College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743, Republic of Korea
| | - Sei-Ryang Oh
- Natural Medicine Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gun, ChungBuk 363-883, Republic of Korea
| | - Young-Joon Surh
- College of Pharmacy, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea,
| | - Yong-Yeon Cho
- College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743, Republic of Korea,
| |
Collapse
|
4
|
Chen M, Shabashvili D, Nawab A, Yang SX, Dyer LM, Brown KD, Hollingshead M, Hunter KW, Kaye FJ, Hochwald SN, Marquez VE, Steeg P, Zajac-Kaye M. DNA methyltransferase inhibitor, zebularine, delays tumor growth and induces apoptosis in a genetically engineered mouse model of breast cancer. Mol Cancer Ther 2012; 11:370-82. [PMID: 22203734 PMCID: PMC7457145 DOI: 10.1158/1535-7163.mct-11-0458] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Zebularine is a novel potent inhibitor of both cytidine deaminase and DNA methylation. We examined the effect of zebularine on mammary tumor growth in genetically engineered MMTV-PyMT transgenic mice that develop mammary tumors at 60 days of age with 100% penetrance. The MMTV-PyMT transgenic mice were randomized at 46 days of age into control (n = 25) and zebularine (n = 25) treatment groups and monitored for parameters of tumor growth. Zebularine was administered at 5 mg/mL in drinking water. We observed a significant delay in the growth of mammary tumors in zebularine-treated mice with a statistically significant reduction (P = 0.0135) in total tumor burden at 94 days of age when the mice were sacrificed. After 48 days of zebularine treatment, the tumors were predominantly necrotic compared with untreated animals. In addition, a high apoptotic index by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay was observed as early as 13 days following treatment. Immunoblot analysis showed depletion of DNMT1 and partial depletion of DNMT3b after zebularine treatment. Microarray analyses of global gene expression identified upregulation of twelve methylation-regulated genes as well as a set of candidate cancer genes that participate in cell growth and apoptosis. In summary, zebularine inhibits the growth of spontaneous mammary tumors and causes early onset of tumor cell necrosis and apoptosis in a genetically engineered mouse model of breast cancer. Defining the parameters of zebularine-mediated tumor inhibition may advance the future development of DNA methyltransferase inhibitors as an effective cancer treatment.
Collapse
Affiliation(s)
- Min Chen
- Departments of Anatomy and Cell Biology, University of Florida, Gainesville, Florida
- Departments of Medicine, University of Florida, Gainesville, Florida
| | - Daniel Shabashvili
- Departments of Anatomy and Cell Biology, University of Florida, Gainesville, Florida
| | - Akbar Nawab
- Departments of Anatomy and Cell Biology, University of Florida, Gainesville, Florida
| | - Sherry X. Yang
- Departments of National Clinical Target Validation Laboratory, Bethesda, Maryland
| | - Lisa M. Dyer
- Departments of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida
| | - Kevin D. Brown
- Departments of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida
| | - Melinda Hollingshead
- Departments of Developmental Therapeutics Program, NCI-Frederick, Bethesda, Maryland
| | - Kent W. Hunter
- Departments of Laboratory of Cancer Biology and Genetics, Bethesda, Maryland
| | - Frederic J. Kaye
- Departments of Medicine, University of Florida, Gainesville, Florida
| | | | - Victor E. Marquez
- Departments of Laboratory of Medicinal Chemistry, Bethesda, Maryland
| | - Patricia Steeg
- Departments of Laboratory of Molecular Pharmacology, National Cancer Institute, Bethesda, Maryland
| | - Maria Zajac-Kaye
- Departments of Anatomy and Cell Biology, University of Florida, Gainesville, Florida
- Departments of Medicine, University of Florida, Gainesville, Florida
| |
Collapse
|
5
|
Transgenic expression of polyomavirus middle T antigen in the mouse prostate gives rise to carcinoma. J Virol 2011; 85:5581-92. [PMID: 21411524 DOI: 10.1128/jvi.02609-10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The middle T (MT) antigen of polyomavirus has provided fundamental insights into the regulation of mammalian cell growth in vitro and important animal models for the analysis of tumor induction. The mouse mammary tumor virus (MMTV)-MT model of breast cancer has been important for probing the cellular signaling pathways in mammary tumorigenesis. MT itself has no intrinsic enzymatic activity but, rather, transforms by binding to and activating key intracellular signaling molecules, phosphatidylinositol 3-kinase (PI3-kinase) being the best studied of these. Thus, MT mimics a constitutively activated receptor tyrosine kinase (RTK). Our recent work suggests that MT signaling, like that of RTKs, is often quite dependent on cellular context in vitro. Here, we examine contextual effects on signaling in animal models as well. In this study, we generated transgenic mice in which MT is expressed in the mouse prostate under the control of an (ARR)2-Probasin promoter. All male transgenic mice displayed mouse prostatic intraepithelial neoplasia (mPIN) in the ventral and dorsal/lateral prostate as early as 8 weeks of age. Notably, during the course of tumor development over time, invasive cancer, reactive stroma, and infiltration of inflammatory cells were seen. Transcriptional profiling analyses show regulation of multiple pathways, with marked upregulation of both the NF-κB and inflammatory pathways. Comparison of expression profiles of our MT prostate model with those from an MMTV-MT breast model (23) shows both tissue-specific and tissue-independent MT effects. The signature of genes regulated by MT in a tissue-independent manner may have prognostic value.
Collapse
|
6
|
Chen P, O'Neal JF, Ebelt ND, Cantrell MA, Mitra S, Nasrazadani A, Vandenbroek TL, Heasley LE, Van Den Berg CL. Jnk2 effects on tumor development, genetic instability and replicative stress in an oncogene-driven mouse mammary tumor model. PLoS One 2010; 5:e10443. [PMID: 20454618 PMCID: PMC2862739 DOI: 10.1371/journal.pone.0010443] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Accepted: 04/08/2010] [Indexed: 02/08/2023] Open
Abstract
Oncogenes induce cell proliferation leading to replicative stress, DNA damage and genomic instability. A wide variety of cellular stresses activate c-Jun N-terminal kinase (JNK) proteins, but few studies have directly addressed the roles of JNK isoforms in tumor development. Herein, we show that jnk2 knockout mice expressing the Polyoma Middle T Antigen transgene developed mammary tumors earlier and experienced higher tumor multiplicity compared to jnk2 wildtype mice. Lack of jnk2 expression was associated with higher tumor aneuploidy and reduced DNA damage response, as marked by fewer pH2AX and 53BP1 nuclear foci. Comparative genomic hybridization further confirmed increased genomic instability in PyV MT/jnk2−/− tumors. In vitro, PyV MT/jnk2−/− cells underwent replicative stress and cell death as evidenced by lower BrdU incorporation, and sustained chromatin licensing and DNA replication factor 1 (CDT1) and p21Waf1 protein expression, and phosphorylation of Chk1 after serum stimulation, but this response was not associated with phosphorylation of p53 Ser15. Adenoviral overexpression of CDT1 led to similar differences between jnk2 wildtype and knockout cells. In normal mammary cells undergoing UV induced single stranded DNA breaks, JNK2 localized to RPA (Replication Protein A) coated strands indicating that JNK2 responds early to single stranded DNA damage and is critical for subsequent recruitment of DNA repair proteins. Together, these data support that JNK2 prevents replicative stress by coordinating cell cycle progression and DNA damage repair mechanisms.
Collapse
Affiliation(s)
- Peila Chen
- Division of Pharmacology and Toxicology, Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, United States of America
| | - Jamye F. O'Neal
- Division of Pharmacology and Toxicology, Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, United States of America
| | - Nancy D. Ebelt
- Institute of Cellular and Molecular Biology, School of Biological Sciences, The University of Texas at Austin, Austin, Texas, United States of America
| | - Michael A. Cantrell
- Institute of Cellular and Molecular Biology, School of Biological Sciences, The University of Texas at Austin, Austin, Texas, United States of America
| | - Shreya Mitra
- Division of Pharmacology and Toxicology, Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, United States of America
| | - Azadeh Nasrazadani
- Division of Pharmacology and Toxicology, Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, United States of America
| | - Tracy L. Vandenbroek
- Division of Pharmacology and Toxicology, Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, United States of America
| | - Lynn E. Heasley
- Department of Craniofacial Biology, University of Colorado Denver Anshutz Medical Campus, Aurora, Colorado, United States of America
| | - Carla L. Van Den Berg
- Division of Pharmacology and Toxicology, Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, United States of America
- * E-mail:
| |
Collapse
|
7
|
Fluck MM, Schaffhausen BS. Lessons in signaling and tumorigenesis from polyomavirus middle T antigen. Microbiol Mol Biol Rev 2009; 73:542-63, Table of Contents. [PMID: 19721090 PMCID: PMC2738132 DOI: 10.1128/mmbr.00009-09] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The small DNA tumor viruses have provided a very long-lived source of insights into many aspects of the life cycle of eukaryotic cells. In recent years, the emphasis has been on cancer-related signaling. Here we review murine polyomavirus middle T antigen, its mechanisms, and its downstream pathways of transformation. We concentrate on the MMTV-PyMT transgenic mouse, one of the most studied models of breast cancer, which permits the examination of in situ tumor progression from hyperplasia to metastasis.
Collapse
Affiliation(s)
- Michele M Fluck
- Department of Microbiology and Molecular Genetics, Interdepartmental Program in Cell and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
| | | |
Collapse
|
8
|
Schaffhausen BS, Roberts TM. Lessons from polyoma middle T antigen on signaling and transformation: A DNA tumor virus contribution to the war on cancer. Virology 2008; 384:304-16. [PMID: 19022468 DOI: 10.1016/j.virol.2008.09.042] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Accepted: 09/30/2008] [Indexed: 01/16/2023]
Abstract
Middle T antigen (MT) is the principal oncogene of murine polyomavirus. Its study has led to the discovery of the roles of tyrosine kinase and phosphoinositide 3-kinase (PI3K) signaling in mammalian growth control and transformation. MT is necessary for viral transformation in tissue culture cells and tumorigenesis in animals. When expressed alone as a transgene, MT causes tumors in a wide variety of tissues. It has no known catalytic activity, but rather acts by assembling cellular signal transduction molecules. Protein phosphatase 2A, protein tyrosine kinases of the src family, PI3K, phospholipase Cgamma1 as well as the Shc/Grb2 adaptors are all assembled on MT. Their activation sets off a series of signaling cascades. Analyses of virus mutants as well as transgenic animals have demonstrated that the effects of a given signal depend not only tissue type, but on the genetic background of the host animal. There remain many opportunities as we seek a full molecular understanding of MT and apply some of its lessons to human cancer.
Collapse
Affiliation(s)
- Brian S Schaffhausen
- Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111, USA
| | | |
Collapse
|
9
|
|
10
|
Chen L, Wang X, Fluck MM. Independent contributions of polyomavirus middle T and small T to the regulation of early and late gene expression and DNA replication. J Virol 2006; 80:7295-307. [PMID: 16840310 PMCID: PMC1563708 DOI: 10.1128/jvi.00679-06] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We previously showed that murine polyomavirus mutants that lack both middle T (MT) and small T (ST) functions have a severe pleiotropic defect in early and late viral gene expression as well as genome amplification. The respective contribution of MT and ST to this phenotype was unclear. This work separates the roles of MT and ST in both permissive mouse cells and nonpermissive rat cells. It demonstrates for the first time a role for both proteins. To gain insight into the signaling pathways that might be required, we focused on MT and its mutants. The results show that each of the major MT signaling connections, Shc, phosphatidylinositol 3'-kinase, and phospholipase C gamma1, could contribute in an additive way. Unexpectedly, a mutant lacking all these connections because the three major tyrosines had been converted to phenylalanine retained some activity. A mutant in which all six MT C-terminal tyrosines had been mutated was inactive. This suggests a novel signaling pathway for MT that uses the minor tyrosines. What is common to ST and the individual MT signaling pathways is the ability to signal to the polyomavirus enhancer, in particular to the crucial AP-1 and PEA3/ets binding sites. This connection explains the pleiotropy of MT and ST effects on transcription and DNA replication.
Collapse
Affiliation(s)
- Li Chen
- Department of Microbiology and Molecular Genetics, Interdepartmental Program in Cell and Molecular Biology, Michigan State University, East Lansing, MI 48824-1101, USA
| | | | | |
Collapse
|
11
|
Qiu TH, Chandramouli GVR, Hunter KW, Alkharouf NW, Green JE, Liu ET. Global expression profiling identifies signatures of tumor virulence in MMTV-PyMT-transgenic mice: correlation to human disease. Cancer Res 2004; 64:5973-81. [PMID: 15342376 DOI: 10.1158/0008-5472.can-04-0242] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
FVB/N-Tg (MMTV-PyMT)(634Mul)-transgenic mice develop multifocal mammary tumors with a high incidence of pulmonary metastasis. We have demonstrated previously that mammary tumors derived from transgene-positive F1 progeny in particular inbred strains display altered latency, tumor growth rates, and metastatic rates when compared with the FVB/NJ homozygous parent. To identify genes with expression that might be critical in modifying the biological behavior of MMTV-PyMT tumors, we performed a detailed comparative analysis of expression profiles from mammary tumors arising in the parental FVB/NJ background and F1 progeny from crosses with I/LnJ, LP/J, MOLF/Ei, and NZB/B1NJ mice. Compared with normal mammary glands, gene expression profiles of tumors from all five strains exhibited up-regulation of genes involved in cell growth (e.g., Cks1 and CDC25C) and down-regulation of cell adhesion molecules, with many genes associated previously with human breast cancer such as STAT2, CD24 antigen, gelsolin, and lipocalin2. To identify genes with significant variation in expression between the five different genotypes, significance analysis of microarrays (SAM) and one-way ANOVA were used. Three definable groupings of tumors were identified: (a) tumors derived in the LP/J F1 and MOLF/Ei F1 strains in which tumor growth and dissemination are suppressed and latency prolonged; (b) the most aggressive tumors from the FVB/NJ parental strain and I/LnJ F1 genomic backgrounds; and (c) an intermediate virulence phenotype with tumors from NZB/B1NJ-F1 crosses. These array based assessments correlated well with a composite phenotype ranking using a "virulence" index. The gene expression signature that is associated with a high metastatic rate in the mouse contains the same 17 genes described recently as the signature gene set predictive of metastasis in human tumors (1) with 16 of the 17 genes exhibiting the same directional change in expression associated with human metastases. These results demonstrate that the genetic analysis of mouse models of tumorigenesis may be highly relevant to human cancer and that the metastatic phenotype of a tumor may be affected by the germline genetic configuration of the host.
Collapse
MESH Headings
- Animals
- Antigens, Polyomavirus Transforming/genetics
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/pathology
- Disease Models, Animal
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic/genetics
- Humans
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/metabolism
- Mammary Neoplasms, Experimental/pathology
- Mammary Neoplasms, Experimental/virology
- Mammary Tumor Virus, Mouse/genetics
- Mice
- Mice, Transgenic
- Oligonucleotide Array Sequence Analysis
Collapse
Affiliation(s)
- Ting Hu Qiu
- Laboratory of Cell Regulation and Carcinogenesis, Cancer Research Center, National Cancer Institute, Bethesda, Maryland 20892, USA
| | | | | | | | | | | |
Collapse
|
12
|
Kielosto M, Nummela P, Katainen R, Leaner V, Birrer MJ, Hölttä E. Reversible Regulation of the Transformed Phenotype of Ornithine Decarboxylase- and Ras-Overexpressing Cells by Dominant-Negative Mutants of c-Jun. Cancer Res 2004; 64:3772-9. [PMID: 15172983 DOI: 10.1158/0008-5472.can-3188-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
c-Jun is an oncogenic transcription factor involved in the regulation of cell proliferation, apoptosis and transformation. We have previously reported that cell transformations induced by ornithine decarboxylase (ODC) and c-Ha-ras oncogene, commonly activated in various cancer cells, are associated with constitutively increased phosphorylation of c-Jun on Ser residues 63 and 73. In the present study, we examined the significance of c-Jun phosphorylation and activation on the phenotype of the ODC- and ras-transformants, by using specific inhibitors and dominant-negative (DN) mutants to c-Jun NH(2)-terminal kinase (JNK) and its upstream kinase, SEK1/MKK4 (mitogen-activated protein kinase kinase 4), and to c-Jun. The transformed morphology of both the ODC- and ras-expressing cells was reversed partially by JNK inhibitors and DN JNK1, more effectively by DN SEK1/MKK4 and phosphorylation-deficient c-Jun mutants (c-Jun(S63,73A), c-Jun(S63,73A,T91,93A)) and most potently by a transactivation domain deletion mutant of c-Jun (TAM67). Moreover, tetracycline-inducible TAM67 expression in ODC- and ras-transformed cells showed that the transformed phenotype of the cells is reversibly regulatable. TAM67 also inhibited the tumorigenicity of the cells in nude mice. These inducible cell lines, together with their parental cell lines, provide good models to identify the genes and proteins relevant to cellular transformation.
Collapse
Affiliation(s)
- Mari Kielosto
- Haartman Institute and Helsinki University Central Hospital, Department of Pathology, University of Helsinki, Helsinki, Finland
| | | | | | | | | | | |
Collapse
|
13
|
Winnischofer SMB, de Oliveira MLS, Sogayar MC. Suppression of AP-1 constitutive activity interferes with polyomavirus MT antigen transformation ability. J Cell Biochem 2004; 90:253-66. [PMID: 14505342 DOI: 10.1002/jcb.10628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Polyomavirus (Py) encodes a potent oncogene, the middle T antigen (MT), that induces cell transformation by binding to and activating several cytoplasmic proteins which take part in transduction of growth factors-induced mitogenic signal to the nucleus. We have previously reported that the AP-1 transcriptional complex is a target for MT during cell transformation although, its activation was not sufficient for establishment of the transformed phenotype. Here we show that expression of a dominant-negative cJun mutant in MT transformed cell lines inhibits its transformation ability, indicating that constitutive AP-1 activity is necessary for cell transformation mediated by MT. Evidences also suggest that proliferation of MT transformed cells in low serum concentrations and their ability to form colonies in agarose are controlled by distinct mechanisms.
Collapse
|
14
|
Nicholson PR, Empereur S, Glover HR, Dilworth SM. ShcA tyrosine phosphorylation sites can replace ShcA binding in signalling by middle T-antigen. EMBO J 2001; 20:6337-46. [PMID: 11707405 PMCID: PMC125738 DOI: 10.1093/emboj/20.22.6337] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
ShcA and Grb2 are crucial components in signalling by most tyrosine kinase-associated receptors. How ever, it is not clear whether Grb2 bound directly to the receptor is equivalent to Grb2 associated via ShcA. We have used signalling stimulated by the middle T-antigen (MT) of polyoma virus to address this question. The two known Grb2-binding sites from murine ShcA, 313Y and 239/240YY, could functionally replace the MT ShcA-interacting region in transformation assays using Rat2 fibroblasts. This demonstrates that signal output from membrane-bound ShcA requires only these two sequences and the ShcA-binding site in MT does not recruit other signalling molecules. Two standard Grb2-interacting sequences, either from the EGF receptor or the ShcA 313Y region, could not replace the requirement for ShcA binding to MT, indicating an enhanced role for the ShcA 239/240YY motif. Sos1 and the docking protein Gab1 are brought into the MT complex through Grb2 association and this may be more effective using the 239/240YY sequence.
Collapse
Affiliation(s)
| | | | | | - Stephen M. Dilworth
- Department of Metabolic Medicine, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
Corresponding author e-mail:
| |
Collapse
|
15
|
Chen L, Fluck MM. Role of middle T-small T in the lytic cycle of polyomavirus: control of the early-to-late transcriptional switch and viral DNA replication. J Virol 2001; 75:8380-9. [PMID: 11507183 PMCID: PMC115083 DOI: 10.1128/jvi.75.18.8380-8389.2001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A comparative analysis of the lytic cycle of wild-type polyomavirus and middle T and small T defective mutants was carried out in the A2 genetic background. The results contrast with those obtained in comparisons between the hr-t type and their middle-T small-T-producing partners as previously described (20). The A2-derived mutants were found to share the maturation defect previously described for the hr-t mutants. However, their defect in DNA replication was more acute, resulting in a 5- to 100-fold decrease in the accumulation of viral genomes. Furthermore, their gene expression pattern was affected. A2-derived mutants displayed an early defect resulting in a 4- to 16-h delay in the expression of large T, and an alteration of the early-to-late transcriptional switch. In wild-type A2 infection, this switch is characterized by a large increase in the accumulation of early transcripts followed by late transcripts after the appearance of middle T and small T proteins and the onset of viral DNA replication (L. Chen and M. M. Fluck, J. Virol. 75: 8368-8379, 2001). In the mutant infection, increases in both classes of transcripts were delayed and reduced, but the effect on early transcripts was more pronounced. As has been described previously for the hr-t mutants (E. Goldman, J. Hattori, and T. Benjamin, Cell 13:505-513, 1979), the magnitude of these defects depended upon experimental conditions. Experiments using cytosine beta-arabinofuranoside to reduce genome amplification suggest that the effect of middle T-small T on the transcriptional switch is not solely mediated by the effect of these protein(s) on increasing the number of templates. These data provide the first direct demonstration of an effect of middle T and/or small T in the viral transcription pattern during viral infection. The results agree with previous results obtained with plasmid reporters and with our understanding that the downstream targets of the middle T signaling pathway include three transcription factors that have binding sites in the enhancer domain that play a key regulatory role in the expression of the viral genes.
Collapse
Affiliation(s)
- L Chen
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824-1101, USA
| | | |
Collapse
|
16
|
Gottlieb KA, Villarreal LP. Natural biology of polyomavirus middle T antigen. Microbiol Mol Biol Rev 2001; 65:288-318 ; second and third pages, table of contents. [PMID: 11381103 PMCID: PMC99028 DOI: 10.1128/mmbr.65.2.288-318.2001] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
"It has been commented by someone that 'polyoma' is an adjective composed of a prefix and suffix, with no root between--a meatless linguistic sandwich" (C. J. Dawe). The very name "polyomavirus" is a vague mantel: a name given before our understanding of these viral agents was clear but implying a clear tumor life-style, as noted by the late C. J. Dawe. However, polyomavirus are not by nature tumor-inducing agents. Since it is the purpose of this review to consider the natural function of middle T antigen (MT), encoded by one of the seemingly crucial transforming genes of polyomavirus, we will reconsider and redefine the virus and its MT gene in the context of its natural biology and function. This review was motivated by our recent in vivo analysis of MT function. Using intranasal inoculation of adult SCID mice, we have shown that polyomavirus can replicate with an MT lacking all functions associated with transformation to similar levels to wild-type virus. These observations, along with an almost indistinguishable replication of all MT mutants with respect to wild-type viruses in adult competent mice, illustrate that MT can have a play subtle role in acute replication and persistence. The most notable effect of MT mutants was in infections of newborns, indicating that polyomavirus may be highly adapted to replication in newborn lungs. It is from this context that our current understanding of this well-studied virus and gene is presented.
Collapse
Affiliation(s)
- K A Gottlieb
- Department of Molecular Biology and Biochemistry, Biological Sciences II, University of California-Irvine, Irvine, CA 92697, USA
| | | |
Collapse
|
17
|
da Costa SR, Wang Y, Vilalta PM, Schönthal AH, Hamm-Alvarez SF. Changes in cytoskeletal organization in polyoma middle T antigen-transformed fibroblasts: involvement of protein phosphatase 2A and src tyrosine kinases. CELL MOTILITY AND THE CYTOSKELETON 2000; 47:253-68. [PMID: 11093247 DOI: 10.1002/1097-0169(200012)47:4<253::aid-cm1>3.0.co;2-s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The major transforming activity of polyomavirus, middle T antigen, targets several cellular regulatory effectors including protein phosphatase 2A and src tyrosine kinases. Although transformed cells exhibit profound morphological changes, little is known about how middle T antigen-induced changes in the cellular regulatory environment specifically affect the cytoskeleton. We have investigated these changes in 10T(1/2) mouse fibroblasts transformed with polyoma middle T antigen. Immunofluorescence microscopy revealed that expression of middle T antigen (Pym T cells) depleted the stable (acetylated) microtubule array and increased the sensitivity of dynamic (tyrosinated) microtubules to nocodazole-induced disassembly. These effects were associated with a modest but statistically significant (P</=0.05) increase in recovery of protein phosphatase 2A activity with microtubules. Middle T antigen expression also depleted the normal cellular complement of actin stress fibers and focal adhesions, in parallel with changes in the distribution of src tyrosine kinases. Herbimycin A promoted recovery of paxillin and phosphotyrosine into nascent focal adhesion sites, in addition to restoring normal src tyrosine kinase distribution. However, herbimycin A did not restore actin stress fibers or parental-type microtubules to Pym T cells. We suggest that regulation of the microtubule array by middle T antigen may occur through direct effects including redistribution of protein phosphatase 2A as well as indirect effects such as altered interactions with actin-based stress fibers.
Collapse
Affiliation(s)
- S R da Costa
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, USA
| | | | | | | | | |
Collapse
|
18
|
Doherty J, Freund R. Middle T antigen activation of signal transduction pathways does not overcome p53-mediated growth arrest. J Virol 1999; 73:7882-5. [PMID: 10438885 PMCID: PMC104322 DOI: 10.1128/jvi.73.9.7882-7885.1999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/1999] [Accepted: 05/17/1999] [Indexed: 11/20/2022] Open
Abstract
Polyomavirus middle T antigen does not overcome p53-mediated G(1) arrest in mouse embryo fibroblasts. Middle T antigen still associates with the signaling molecules phosphatidylinositol 3-kinase and SHC and activates the transcriptional activity of c-Myc and AP1 in p53-arrested cells. Examination of cell cycle regulatory proteins indicated that p53 does not interfere with these mitogenic signals but acts later in the G(1) phase of the cell cycle.
Collapse
Affiliation(s)
- J Doherty
- Molecular and Cell Biology Program, University of Maryland, Baltimore, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | | |
Collapse
|
19
|
Chen Y, Freund R, Listerud M, Wang Z, Talmage DA. Retinoic acid inhibits transformation by preventing phosphatidylinositol 3-kinase dependent activation of the c-fos promoter. Oncogene 1999; 18:139-48. [PMID: 9926928 DOI: 10.1038/sj.onc.1202272] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Retinoic acid inhibits transformation of cells by polyoma virus middle T oncoprotein. Inhibition of transformation results from a retinoic acid-dependent failure of cells to fully express the c-fos proto-oncogene. Retinoic acid prevents transactivation of the c-fos promoter by disrupting signaling between tyrosine kinases at the plasma membrane and trans-acting factors at the c-fos promoter. We used complementary genetic, biochemical and molecular approaches to demonstrate that: (1) phosphatidylinositol 3-kinase signaling is the principle mechanism of polyoma virus middle T oncoprotein activation of c-fos expression; (2) middle T/phosphatidylinositol 3-kinase transactivation of the c-fos promoter and transformation of cells requires activation of both the small GTP-binding protein Rac and Jun N-terminal kinase; (3) retinoic acid inhibits activation of Jun N-terminal kinase, thereby preventing c-fos transactivation and transformation; and (4) middle T activation of c-fos transcription requires both the serum response element and the promoter proximal cyclic AMP response element. These studies identify a novel target through which retinoids prevent oncogenic transformation.
Collapse
Affiliation(s)
- Y Chen
- Institute of Human Nutrition, Columbia University, New York, New York, USA
| | | | | | | | | |
Collapse
|
20
|
Herdegen T, Leah JD. Inducible and constitutive transcription factors in the mammalian nervous system: control of gene expression by Jun, Fos and Krox, and CREB/ATF proteins. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1998; 28:370-490. [PMID: 9858769 DOI: 10.1016/s0165-0173(98)00018-6] [Citation(s) in RCA: 1054] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This article reviews findings up to the end of 1997 about the inducible transcription factors (ITFs) c-Jun, JunB, JunD, c-Fos, FosB, Fra-1, Fra-2, Krox-20 (Egr-2) and Krox-24 (NGFI-A, Egr-1, Zif268); and the constitutive transcription factors (CTFs) CREB, CREM, ATF-2 and SRF as they pertain to gene expression in the mammalian nervous system. In the first part we consider basic facts about the expression and activity of these transcription factors: the organization of the encoding genes and their promoters, the second messenger cascades converging on their regulatory promoter sites, the control of their transcription, the binding to dimeric partners and to specific DNA sequences, their trans-activation potential, and their posttranslational modifications. In the second part we describe the expression and possible roles of these transcription factors in neural tissue: in the quiescent brain, during pre- and postnatal development, following sensory stimulation, nerve transection (axotomy), neurodegeneration and apoptosis, hypoxia-ischemia, generalized and limbic seizures, long-term potentiation and learning, drug dependence and withdrawal, and following stimulation by neurotransmitters, hormones and neurotrophins. We also describe their expression and possible roles in glial cells. Finally, we discuss the relevance of their expression for nervous system functioning under normal and patho-physiological conditions.
Collapse
Affiliation(s)
- T Herdegen
- Institute of Pharmacology, University of Kiel, Hospitalstrasse 4, 24105, Kiel,
| | | |
Collapse
|
21
|
Mullane KP, Ratnofsky M, Culleré X, Schaffhausen B. Signaling from polyomavirus middle T and small T defines different roles for protein phosphatase 2A. Mol Cell Biol 1998; 18:7556-64. [PMID: 9819441 PMCID: PMC109336 DOI: 10.1128/mcb.18.12.7556] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/1998] [Accepted: 09/10/1998] [Indexed: 12/25/2022] Open
Abstract
Polyomavirus causes a broad spectrum of tumors as the result of the action of its early proteins. This work compares signaling from middle T antigen (MT), the major transforming protein, to that from small T antigen (ST). The abilities of MT mutants to promote cell cycle progression in serum-starved NIH 3T3 cells were compared. Transformation-defective mutants lacking association with SHC or with phosphatidylinositol 3-kinase (PI3-K) retained the ability to induce DNA synthesis as measured by bromodeoxyuridine incorporation. Only when both interactions were lost in the Y250F/Y315F double mutant was MT inactive. ST promoted cell cycle progression in a manner dependent on its binding of protein phosphatase 2A (PP2A). Since the Y250F/Y315F MT mutant was wild type for PP2A binding yet unable to promote cell cycle progression, while ST was capable of promoting cell cycle progression, these experiments revealed a functional difference in MT and ST signaling via PP2A. Assays testing the abilities of MT and ST to induce the c-fos promoter and to activate c-jun kinase led to the same conclusion. ST, but not Y250F/Y315F MT, was able to activate the c-fos promoter through its interaction with PP2A. In contrast, MT, but not ST, was able to activate c-jun kinase by virtue of its interaction with PP2A.
Collapse
Affiliation(s)
- K P Mullane
- Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts, USA
| | | | | | | |
Collapse
|
22
|
Tan L, Andersen MH, Elliott T, Haurum JS. An improved assembly assay for peptide binding to HLA-B*2705 and H-2K(k) class I MHC molecules. J Immunol Methods 1997; 209:25-36. [PMID: 9448031 DOI: 10.1016/s0022-1759(97)00142-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The assembly assay for peptide binding to class I major histocompatibility complex (MHC) is based on the ability to stabilise MHC class I molecules from mutant cell lines by the addition of suitable peptides. Such cell lines lack a functional transporter associated with antigen presentation (TAP) and as a result accumulate empty, unstable class I molecules in the ER. These dissociate rapidly in cell lysates unless they are stabilised by the addition of an appropriate binding peptide during lysis. The extent of stabilisation of class I molecules is directly related to the binding affinity of the added peptide. However, some MHC class I molecules, including HLA-B * 2705 and H-2Kk are unusually stable in their peptide-receptive state making them inappropriate for analysis using this assay or assays which depend on the ability of peptides to stabilise MHC class I molecules at the cell surface. Here we present an improved method that permits reliable measurements of peptide binding to such class I MHC molecules that are unusually stable in the absence of peptide. Cells are lysed in the presence of peptide and incubated at 4 degrees C. After 2 h, during which peptide binding to empty MHC molecules occurs, the lysate is heated to a temperature which preferentially destabilises those MHC molecules that remain empty. We have used this technique to assay peptide binding to HLA-B * 2705, as well as to the murine allele H-2Kk which also displays a stable phenotype when transfected into TAP-deficient T2 cells and show that this method represents a marked improvement over previous methods in terms of lower background signal and higher recovery of peptide bound molecules.
Collapse
Affiliation(s)
- L Tan
- The Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford, UK
| | | | | | | |
Collapse
|
23
|
Abstract
The oncogenic protein of polyomavirus, middle-T antigen, associated with cell membranes and interacts with a variety of cellular proteins involved in mitogenic signalling. Middle-T antigen may therefore mimic the function of cellular tyrosine kinase growth factor receptors, like the platelet-derived growth factor or epidermal growth factor receptor. Growth factor receptor signalling is initiated upon the binding of a ligand to the extracellular domain of the receptor. This results in activation of the intracellular tyrosine kinase domain of the receptor, followed by receptor phosphorylation, presumably as a consequence of dimerization of two receptor molecules. Similar to middle-T antigen, phosphorylation of growth factor receptors leads to recruitment of cellular signalling molecules downstream in the signalling cascade. In this study, we investigated whether middle-T antigen, similar to tyrosine kinase growth factor receptors, is able to form dimeric signalling complexes. We found that association with cellular membranes was a prerequisite for multimerization, most likely dimer formation. A chimeric middle-T antigen carrying the membrane-targeting sequence of the vesicular stomatitis virus G protein instead of the authentic polyomavirus sequence still dimerized. However, mutants of middle-T antigen unable to associate with 14-3-3 proteins, like d18 and S257A, did not form dimers but were still oncogenic. This indicates that both membrane association and binding of 14-3-3 are necessary for dimer formation of middle-T antigen but that only the former is essential for cell transformation.
Collapse
Affiliation(s)
- M Senften
- Friedrich Miescher Institute, Basel, Switzerland
| | | | | |
Collapse
|
24
|
Abstract
Virus replication and spreading in a host population depends on highly specific interactions of viral proteins with infected cells, resulting in subversion of multiple cellular signal transduction pathways. For instance, viral proteins cause cell cycle progression of the infected host cell in order to establish a cellular environment favourable for virus replication. Of equal importance for successful virus propagation is virus-mediated attenuation of a host's immune response. Many of the pathways controlling these aspects of cell behaviour are regulated by cellular tyrosine kinases. One particular family of these enzymes, Src family kinases, are involved in processing signals emanating from the plasma membrane upon stimulation by growth factors, by cell-substratum or by cell-cell contact. Two families of DNA viruses, polyoma- and herpesviruses, encode proteins targeted at tyrosine kinases. The middle-T antigens expressed by mouse and hamster polyomavirus associate with and activate Src family tyrosine kinases. Two members of the herpes family of DNA viruses, Epstein-Barr virus (EBV) and herpesvirus saimiri (HVS), encode proteins, LMP2A and Tip, respectively, that associate with cellular tyrosine kinases of the Src and Syk/Zap family. Upon association with these viral proteins, the activity of these tyrosine kinases is changed resulting in altered signal output. Middle-T, LMP2A and Tip are therefore excellent tools to study the regulation of Src family kinases.
Collapse
Affiliation(s)
- N Dunant
- Friedrich Miescher-Institute, Basel, Switzerland
| | | |
Collapse
|
25
|
Bauer PH, Benjamin TL. A novel 39-kilodalton membrane protein binds GTP in polyomavirus-transformed cells. J Virol 1997; 71:4128-32. [PMID: 9094695 PMCID: PMC191570 DOI: 10.1128/jvi.71.5.4128-4132.1997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
To investigate the possible involvement of GTP-binding proteins in transformation by the DNA tumor virus polyomavirus, the GTP-binding activities of Ras-like proteins and G protein alpha subunit proteins were examined in polyomavirus-transformed cells. No differences in the degrees or patterns of expression of Ras-like proteins were observed. However, a 39-kDa protein specifically bound GTP in membranes from polyomavirus-transformed cells. This protein was not seen in nontransformed or lytically infected cells or in phenotypically normal revertants of polyomavirus-transformed cells. It reappeared, however, in spontaneous retransformants derived from the revertants. The 39-kDa protein was not found stably associated with polyomavirus T antigens, nor was it phosphorylated on tyrosine. The 39-kDa protein was not recognized by an antiserum specific for members of the Gi alpha subfamily of G proteins or by antisera against all other known GTP-binding proteins of similar molecular mass. These results suggest that this novel 39-kDa GTP-binding membrane protein is observed as part of a long-term response that accompanies stable transformation by the virus.
Collapse
Affiliation(s)
- P H Bauer
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
26
|
Bergqvist A, Söderbärg K, Magnusson G. Altered susceptibility to tumor necrosis factor alpha-induced apoptosis of mouse cells expressing polyomavirus middle and small T antigens. J Virol 1997; 71:276-83. [PMID: 8985347 PMCID: PMC191048 DOI: 10.1128/jvi.71.1.276-283.1997] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Infection with some virus types induces susceptibility to the cytotoxic effect of tumor necrosis factor alpha (TNF-alpha). To investigate whether expression of polyomavirus proteins has this effect on cells, the TNF-alpha sensitivity of C127 and L929 mouse cells transfected with viral DNA was analyzed. Expression of all three polyomavirus early proteins, the tumor (T) antigens, had no apparent effect. In contrast, middle T antigen by itself induced hypersensitivity to TNF-alpha. This effect was reversed by retransfection of the cells with DNA encoding small T antigen. Expression of this polypeptide also decreased the sensitivity of bovine papillomavirus type 1-transformed cells to TNF-alpha, showing that the protective function of the polyomavirus small T antigen was not strictly linked to a middle-T-antigen-induced event. Mouse and human TNF-alpha had the same effect on normal and transformed mouse cells, suggesting that this effect was mediated by TNF receptor 1. Consistent with this conclusion, all cell clones used in the experiments expressed TNF receptor 1 at similar levels, while we failed to detect TNF receptor 2. The amount of receptor on the cells was not influenced by binding of the ligand. Addition of TNF-alpha at cytotoxic concentrations to cells expressing middle T antigen by itself resulted in significant fragmentation of chromosomal DNA after only a few hours, indicating induction of apoptosis. Addition of the cytokine to these cells also leads to release of arachidonic acid, showing that phospholipase A2 was activated. However, production of arachidonic acid did not appear to significantly precede loss of cell viability.
Collapse
Affiliation(s)
- A Bergqvist
- Department of Medical Immunology and Microbiology, Uppsala University Biomedical Centre, Sweden
| | | | | |
Collapse
|
27
|
Joe AK, Ferrari G, Jiang HH, Liang XH, Levine B. Dominant inhibitory Ras delays Sindbis virus-induced apoptosis in neuronal cells. J Virol 1996; 70:7744-51. [PMID: 8892895 PMCID: PMC190844 DOI: 10.1128/jvi.70.11.7744-7751.1996] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Mature neurons are more resistant than dividing cells or differentiating neurons to Sindbis virus-induced apoptotic death. Therefore, we hypothesized that mitogenic signal transduction pathways may influence susceptibility to Sindbis virus-induced apoptosis. Since Ras, a 21-kDa GTP-binding protein, plays an important role in cellular proliferation and neuronal differentiation, we investigated the effect of an inducible dominant inhibitory Ras on Sindbis virus-induced death of a rat pheochromocytoma cell line, PC12 cells. Dexamethasone induction of dominant inhibitory Ras (Ha Ras(Asn17)) expression in transfected PC12 cell lines (MMTV-M17-21 and GSrasDN6 cells) resulted in a marked delay in Sindbis virus-induced apoptosis, compared with infected, uninduced cells. The delay in death after Sindbis virus infection in induced versus uninduced PC12 cells was not associated with differences in viral titers or viral infectivity. No delay in Sindbis virus-induced apoptosis was observed in Ha Ras(Asn17)-transfected PC12 cells if dexamethasone induction was initiated less than 12 h before Sindbis virus infection or in wild-type PC12 cells infected with a chimeric Sindbis virus construct that expresses Ha Ras(Asn17). The delay in Sindbis virus-induced apoptosis in induced Ha Ras(Asn17)-transfected PC12 cells was associated with a decrease in cellular DNA synthesis as measured by 5'-bromo-2'-deoxyuridine incorporation. Thus, in PC12 cells, inducible dominant inhibitory Ras inhibits cellular proliferation and delays Sindbis virus-induced apoptosis. These findings suggest that a Ras-dependent signaling pathway is a determinant of neuronal susceptibility to Sindbis virus-induced apoptosis.
Collapse
Affiliation(s)
- A K Joe
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA
| | | | | | | | | |
Collapse
|
28
|
Guo W, Tang WJ, Bu X, Bermudez V, Martin M, Folk WR. AP1 enhances polyomavirus DNA replication by promoting T-antigen-mediated unwinding of DNA. J Virol 1996; 70:4914-8. [PMID: 8763994 PMCID: PMC190441 DOI: 10.1128/jvi.70.8.4914-4918.1996] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
An early step in the initiation of polyomavirus DNA replication is viral large-T-antigen-mediated unwinding of the origin. We report that components of the AP1 transcription factor, Fos and Jun, interact with T antigen in vitro to enhance unwinding of the viral origin. This provides a biochemical basis for the capacity of AP1 to activate viral DNA replication in vivo.
Collapse
Affiliation(s)
- W Guo
- Department of Biochemistry, University of Missouri--Columbia 65202, USA
| | | | | | | | | | | |
Collapse
|
29
|
Urich M, el Shemerly MY, Besser D, Nagamine Y, Ballmer-Hofer K. Activation and nuclear translocation of mitogen-activated protein kinases by polyomavirus middle-T or serum depend on phosphatidylinositol 3-kinase. J Biol Chem 1995; 270:29286-92. [PMID: 7493960 DOI: 10.1074/jbc.270.49.29286] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Several cellular signal transduction pathways activated by middle-T in polyomavirus-transformed cells are required for viral oncogenicity. Here we focus on the role of phosphatidylinositol 3-kinase (PI 3-kinase) and Ras and address the question how these signaling molecules cooperate during cell cycle activation. Ras activation is mediated through association with SHC.GRB2.SOS and leads to increased activity of several members of the mitogen-activated protein (MAP) kinase family, while activation of PI 3-kinase results in the generation of D3-phosphorylated phosphatidylinositides whose downstream targets remain elusive. PI 3-kinase activation might also ensue as a direct consequence of Ras activation. Oncogenicity of middle-T requires stimulation of both Ras- and PI 3-kinase-dependent pathways. Mutants of middle-T incapable to bind either SHC.GRB2.SOS or PI 3-kinase are not oncogenic. Sustained activation and nuclear localization of one of the MAP kinases, ERK1, was observed in wild type but not in mutant middle-T-expressing cells. Wortmannin, an inhibitor of PI 3-kinase, prevented MAP kinase activation and nuclear localization in middle-T-transformed cells. PI 3-kinase activity was also required for activation of the MAP kinase pathway in normal serum-stimulated cells, generalizing the concept that signaling through MAP kinases requires not only Ras-but also PI 3-kinase-mediated signals.
Collapse
Affiliation(s)
- M Urich
- Friedrich Miescher Institute, Basel, Switzerland
| | | | | | | | | |
Collapse
|
30
|
Young AT, Dahl J, Hausdorff SF, Bauer PH, Birnbaum MJ, Benjamin TL. Phosphatidylinositol 3-kinase binding to polyoma virus middle tumor antigen mediates elevation of glucose transport by increasing translocation of the GLUT1 transporter. Proc Natl Acad Sci U S A 1995; 92:11613-7. [PMID: 8524814 PMCID: PMC40452 DOI: 10.1073/pnas.92.25.11613] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Elevation in the rate of glucose transport in polyoma virus-infected mouse fibroblasts was dependent upon phosphatidylinositol 3-kinase (PI 3-kinase; EC 2.7.1.137) binding to complexes of middle tumor antigen (middle T) and pp60c-src. Wild-type polyoma virus infection led to a 3-fold increase in the rate of 2-deoxyglucose (2DG) uptake, whereas a weakly transforming polyoma virus mutant that encodes a middle T capable of activating pp60c-src but unable to promote binding of PI 3-kinase induced little or no change in the rate of 2DG transport. Another transformation-defective mutant encoding a middle T that retains functional binding of both pp60c-src and PI 3-kinase but is incapable of binding Shc (a protein involved in activation of Ras) induced 2DG transport to wild-type levels. Wortmannin (< or = 100 nM), a known inhibitor of PI 3-kinase, blocked elevation of glucose transport in wild-type virus-infected cells. In contrast to serum stimulation, which led to increased levels of glucose transporter 1 (GLUT1) RNA and protein, wild-type virus infection induced no significant change in levels of either GLUT1 RNA or protein. Nevertheless, virus-infected cells did show increases in GLUT1 protein in plasma membranes. These results point to a posttranslational mechanism in the elevation of glucose transport by polyoma virus middle T involving activation of PI 3-kinase and translocation of GLUT1.
Collapse
Affiliation(s)
- A T Young
- Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | |
Collapse
|