301
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Abstract
Akt is well known to enhance malignancy and is recognized as a key target for antineoplastic therapies. However, intriguing findings reported by Yoeli-Lerner et al. in the November 23, 2005 issue of Molecular Cell, suggest a novel, antimetastasis function of Akt: activation of Akt1 inhibited invasion in some cancer cells. One possible mechanism for this surprising phenotype was that Akt activated the E3 ubiquitin ligase HDM2, causing ubiquitination and degradation of NFAT, an invasion-promoting factor. These findings clearly justify further investigations and, if validated in vivo, call for reevaluation of some Akt-targeting therapeutic strategies currently under development.
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Affiliation(s)
- Shannon L Wyszomierski
- Department of Surgical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA
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302
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Li M, Zhang Z, Hill DL, Chen X, Wang H, Zhang R. Genistein, a Dietary Isoflavone, Down-Regulates the MDM2 Oncogene at Both Transcriptional and Posttranslational Levels. Cancer Res 2005; 65:8200-8. [PMID: 16166295 DOI: 10.1158/0008-5472.can-05-1302] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although genistein has chemopreventive effects in several human malignancies, including cancers of the breast, colon, and prostate, the mechanisms of action are not fully understood. Herein we report novel mechanisms whereby genistein down-regulates the MDM2 oncogene, perhaps explaining some of its anticancer activities. In a dose- and time-dependent manner, genistein reduced MDM2 protein and mRNA levels in human cell lines of breast, colon, and prostate cancer; primary fibroblasts; and breast epithelial cells. The inhibitory effects were found at both transcriptional and posttranslational levels and were independent of tyrosine kinase pathways. We found that the NFAT transcription site in the region between -132 and +33 in the MDM2 P2 promoter was responsive to genistein. At the posttranslational level, genistein induced ubiquitination of MDM2, which led to its degradation. Additionally, genistein induced apoptosis and G2 arrest and inhibited proliferation in a variety of human cancer cell lines, regardless of p53 status. We further showed that MDM2 overexpression abrogated genistein-induced apoptosis in vitro and that genistein inhibited MDM2 expression and tumor growth in PC3 xenografts. In conclusion, genistein directly down-regulates the MDM2 oncogene, representing a novel mechanism of its action that may have implications for its chemopreventive and chemotherapeutic effects.
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Affiliation(s)
- Mao Li
- Department of Pharmacology and Toxicology, Division of Clinical Pharmacology, University of Alabama at Birmingham, 35294, USA
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303
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Dabrowska A, Baczyńska D, Widerak K, Laskowska A, Ugorski M. Promoter analysis of the human alpha1,3/4-fucosyltransferase gene (FUT III). ACTA ACUST UNITED AC 2005; 1731:66-73. [PMID: 16199102 DOI: 10.1016/j.bbaexp.2005.08.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Revised: 08/24/2005] [Accepted: 08/26/2005] [Indexed: 11/16/2022]
Abstract
alpha1,3/4-Fucosyltransferase (FUT3) is involved in the synthesis of sialyl Le(a) tetrasaccharide, a tumor-associated carbohydrate antigen. Fucosyltransferases are thought to be important regulatory enzymes in the synthesis of fucosylated structures. However, there are conflicting data on the role of FUT3 in the synthesis of this carbohydrate structure and more studies on the regulation of FUT III gene expression are needed. Therefore, as first step, the promoter of FUT III gene was cloned and characterized. Sequencing data showed the absence of TATA, CAAT, and GC boxes, but many binding sites for transcription factors, previously described in colon cancer cells, were identified. Analysis of enhancer and silencing elements of deletion mutants revealed the presence of basal promoter elements of the FUT III gene in the region -636 to -674 bp from the translation initiation site, and positive and negative regulatory elements within the -674 bp to -854 bp and -854 to -1220 regions, respectively. 5'-RACE analysis showed the presence of two transcripts with 5'-ends localized within the exon A. The 5'-end of the longer transcript extended -229 nucleotides from the translation start codon and contained a sequence corresponding to an Inr element, localizing the putative transcription initiation site within this sequence. The strong correlation between the promoter activity of the FUT III gene and the high expression of sialyl Le(a) observed in different colon carcinoma cell lines seem to confirm the important regulatory role of FUT3 in the synthesis of sialyl Le(a).
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Affiliation(s)
- Anna Dabrowska
- Department of Immunochemistry, Institute of Immunology and Experimental Therapy, Polish Academy of Science, Weigla Str. 12, 53-114 Wrocław, Poland
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304
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Lipscomb EA, Mercurio AM. Mobilization and activation of a signaling competent α6β4integrin underlies its contribution to carcinoma progression. Cancer Metastasis Rev 2005; 24:413-23. [PMID: 16258729 DOI: 10.1007/s10555-005-5133-4] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
This review examines the hypothesis that the function of the alpha 6beta 4 integrin is altered substantially as normal epithelia undergo malignant transformation and progress to invasive carcinoma and that the functions of this integrin contribute to the behavior of aggressive carcinoma cells. Specifically, alpha 6beta 4 functions primarily as an adhesion receptor in normal epithelia, often as a component of hemidesmosomes and associated with intermediate filaments. Factors in the host-tumor microenvironment have the potential to mobilize alpha 6beta 4 from hemidesmosomes and promote its association with F-actin in lamellae and filopodia, a process that is mediated by PKC-dependent phosphorylation of the beta 4 cytoplasmic domain. Importantly, this altered localization of alpha 6beta 4 appears to be coupled to an activation of its signaling potential, which may occur through its association with growth factor receptors or lipid rafts, possibilities that are not mutually exclusive. The primal signaling event triggered by alpha 6beta 4 appears to be activation of PI3-K and this activation has profound consequences on the migration, invasion and survival of carcinoma cells. Arguably, the ability of alpha 6beta 4 to stimulate the PI3-K-dependent translation of VEGF and possibly other growth factors may be the most significant contribution of this integrin to carcinoma because of the potential autocrine and paracrine effects of these factors.
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Affiliation(s)
- Elizabeth A Lipscomb
- Division of Cancer Biology and Angiogenesis, Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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305
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Du Y, Spence SE, Jenkins NA, Copeland NG. Cooperating cancer-gene identification through oncogenic-retrovirus-induced insertional mutagenesis. Blood 2005; 106:2498-505. [PMID: 15961513 PMCID: PMC1895273 DOI: 10.1182/blood-2004-12-4840] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multiple cooperating mutations that deregulate different signaling pathways are required to induce cancer. Identifying these cooperating mutations is a prerequisite for developing better combinatorial therapies for treating cancer. Here we show that cooperating cancer mutations can be identified through oncogenic-retrovirus-induced insertional mutagenesis. Among 13 myeloid leukemias induced by transplanting into mice bone marrow cells infected in vitro with a replication-defective retrovirus carrying the Sox4 oncogene, 9 contained insertional mutations at known or suspected cancer genes. This likely occurred because rare bone marrow cells, in which the oncogenic retrovirus happened to integrate and in which it mutated a cooperating cancer gene, were selected because the host harbored a cooperating cancer mutation. Cooperativity between Sox4 and another gene, Mef2c, was subsequently confirmed in transplantation studies, in which deregulated Mef2c expression was shown to accelerate the myeloid leukemia induced by Sox4. Insertional mutagenesis of cooperating cancer genes by a defective oncogenic retrovirus provides a new method for identifying cooperating cancer genes and could aid in the development of better therapies for treating cancer.
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Affiliation(s)
- Yang Du
- Mouse Cancer Genetics Program, National Cancer Institute, Center for Cancer Research, Frederick, MD, USA
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306
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Kannan S. Neutrophil chemotaxis: autotaxin induced attenuation of purine/pyrimidine signaling precede the overexpression of Integrin(s). Med Hypotheses 2005; 65:197-8. [PMID: 15893145 DOI: 10.1016/j.mehy.2005.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2004] [Accepted: 01/10/2005] [Indexed: 10/25/2022]
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307
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Chen M, O'Connor KL. Integrin α6β4 promotes expression of autotaxin/ENPP2 autocrine motility factor in breast carcinoma cells. Oncogene 2005; 24:5125-30. [PMID: 15897878 DOI: 10.1038/sj.onc.1208729] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In advanced breast carcinomas, the alpha6beta4 integrin is associated with a migratory and invasive phenotype. In our current study, we show that expression of the alpha6beta4 integrin in MDA-MB-435 breast carcinoma cells leads to increased expression of the autocrine motility factor autotaxin, as determined by Affymetrix gene chip, real-time quantitative RT-PCR and immunoblot analyses. We further demonstrate that increased autotaxin secretion from integrin alpha6beta4 expressing cells acts to enhance chemotaxis through its ability to convert lysophosphatidylcholine (LPC) to lysophosphatidic acid (LPA) and accounts for 80% of the motogenic activity of the conditioned medium. We determine that integrin alpha6beta4-dependent overexpression of autotaxin in MDA-MB-435 cells is mediated by NFAT1, but not NFAT5, through the use of siRNAs that specifically target autotaxin, integrin beta4, NFAT1 and NFAT5. Finally, we show by electrophoretic mobility shift assays that two consensus NFAT binding sites found in the autotaxin promoter strongly and specifically bind NFAT1 from integrin alpha6beta4 expressing cells. In summary, we find that the alpha6beta4 integrin potentiates autotaxin expression through the upregulation and activation of NFAT1. These observations highlight for the first time a mechanism by which NFAT transcription factors can facilitate an invasive and motile phenotype downstream of integrin alpha6beta4 signaling.
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Affiliation(s)
- Min Chen
- Department of Surgery and the Sealy Center for Cancer Cell Biology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, USA
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308
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Abstract
SRC family kinases are a group of nine cytoplasmic protein tyrosine kinases essential for many cell functions. Some appear to be ubiquitously expressed, whereas others are highly tissue specific. The ability of members of the SRC family to influence ion transport has been recognized for several years. Mounting evidence suggests a broad role for SRC family kinases in the cell response to both hypertonic and hypotonic stress, and in the ensuing regulatory volume increase or decrease. In addition, members of this tyrosine kinase family participate in the mechanotransduction that accompanies cell membrane deformation. Finally, at least one SRC family member operates in concert with the p38 MAPK to regulate tonicity-dependent gene transcription.
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Affiliation(s)
- David M Cohen
- Division of Nephrology, Mailcode PP262, Oregon Health and Science Univ. 3314 SW US Veterans Hospital Rd., Portland, OR 97239, USA.
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309
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Yoon SO, Shin S, Mercurio AM. Hypoxia stimulates carcinoma invasion by stabilizing microtubules and promoting the Rab11 trafficking of the alpha6beta4 integrin. Cancer Res 2005; 65:2761-9. [PMID: 15805276 DOI: 10.1158/0008-5472.can-04-4122] [Citation(s) in RCA: 180] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Hypoxia plays a key role in tumor cell survival, invasion, and metastasis. Here we show that hypoxia increases tumor cell invasion by the modulation of Rab11, an important molecule for vesicular trafficking, especially membrane protein recycling and translocation of proteins from trans-Golgi network to plasma membrane. Dominant-negative Rab11 dramatically decreased hypoxia-induced invasion of MDA-MB-231 breast carcinoma cells without affecting cell apoptosis. Hypoxia-induced Rab11 trafficking is regulated by microtubule stability, as evidenced by the findings that hypoxia increases Glu tubulin and that colchicine blocks Rab11 trafficking and invasion. Inhibition of GSK-3beta activity by hypoxia seems to be central to microtubule stabilization and invasion. In fact, expression of a dominant-negative GSK-3beta was sufficient to stimulate invasion in normoxia. One target of Rab11-mediated trafficking that contributes to invasion is the integrin alpha6beta4. Hypoxia induced a significant increase in alpha6beta4 surface expression but it had no effect on the surface expression of alpha3beta1. This increase is dependent on Rab11 and stable microtubules. In summary, we identify vesicle trafficking as a novel target of hypoxic stimulation that is important for tumor invasion.
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Affiliation(s)
- Sang-Oh Yoon
- Division of Cancer Biology and Angiogenesis, Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
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310
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Padma S, Sowjanya AP, Poli UR, Jain M, Rao BN, Ramakrishna G. Downregulation of calcineurin activity in cervical carcinoma. Cancer Cell Int 2005; 5:7. [PMID: 15801986 PMCID: PMC1087859 DOI: 10.1186/1475-2867-5-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Accepted: 04/01/2005] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND: Calcineurin (CaN) is an important serine-threonine phosphatase (PP2B), which plays a crucial role in calcium-calmodulin mediated signal transduction events. Calcineurin has been implicated in pathogenesis of various diseases cardiac hypertrophy, diabetic neuropathy and Alzheimer's, however its role in neoplasia remains unclear. RESULTS: In view of this we evaluated the calcineurin activity in serum and biopsy samples collected from women diagnosed with invasive squamous cell carcinoma of cervix. A significant reduction was observed in the calcineurin activity in cancer cervix patients compared to the control group. However the calcineurin activity remained unaltered in the cervical scrapes obtained from patients diagnosed with low-grade squamous intra epithelial lesions (LSIL). Interestingly the downregulation of calcineurin activity in squamous cell carcinomas was not accompanied by any significant change in DNA-binding affinity of the transcriptional factor NFAT (Nuclear Factor of Activated T-cells). All the squamous cell carcinoma samples used in the present study were positive for high-risk human papillomavirus (HPV) types. CONCLUSION: The present study demonstrates the downregulation of calcineurin activity in squamous cell carcinoma of cervix with high risk HPV infection. We conclude that perturbations in calcineurin-mediated pathway may be involved in development of cervical neoplasia.
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Affiliation(s)
- S Padma
- Centre for DNA Fingerprinting and Diagnostics, Nacharam, Hyderabad, A.P, India
| | - A Pavani Sowjanya
- Centre for DNA Fingerprinting and Diagnostics, Nacharam, Hyderabad, A.P, India
| | - Usha Rani Poli
- M.N.J Institute of Oncology and Regional cancer centre, Hyderabad, A.P, India
| | | | - BN Rao
- M.N.J Institute of Oncology and Regional cancer centre, Hyderabad, A.P, India
| | - Gayatri Ramakrishna
- Centre for DNA Fingerprinting and Diagnostics, Nacharam, Hyderabad, A.P, India
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311
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Wang Y, Ko BCB, Yang JY, Lam TTL, Jiang Z, Zhang J, Chung SK, Chung SSM. Transgenic mice expressing dominant-negative osmotic-response element-binding protein (OREBP) in lens exhibit fiber cell elongation defect associated with increased DNA breaks. J Biol Chem 2005; 280:19986-91. [PMID: 15774462 DOI: 10.1074/jbc.m501689200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Osmotic-response element-binding protein (OREBP), also known as TonEBP or NFAT5, is thought to be responsible for the induction of osmolyte-accumulating genes when cells are under hypertonic stress. Recent studies suggest that OREBP also plays a role in water reabsorption in the kidney, T-cell proliferation, and embryonic development. We developed transgenic mice that express the dominant-negative OREBP (OREBPdn) specifically in the lens because our earlier studies showed that it is particularly sensitive to osmotic stress. The transgenic mice developed nuclear cataract soon after birth, suggesting defects in lens development. The developing transgenic lenses showed incomplete elongation of fiber cells and formation of vacuoles. This is accompanied by evidence of DNA strand breaks, activation of p53, and induction of checkpoint kinase, suggesting that the developing fiber cells lacking OREBP are in a similar physiological state as cells experiencing hypertonic stress. These results indicate that OREBP-mediated accumulation of osmolytes is essential during elongation of the lens fiber cells.
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Affiliation(s)
- Yu Wang
- Department of Chemistry, The University of Hong Kong, China.
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312
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Ye P, Simonian M, Nadkarni MA, Decarlo AA, Chapple CC, Hunter N. Identification of epithelial auto-antigens associated with periodontal disease. Clin Exp Immunol 2005; 139:328-37. [PMID: 15654832 PMCID: PMC1809282 DOI: 10.1111/j.1365-2249.2005.02692.x] [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: 11/30/2022] Open
Abstract
We previously reported evidence that patients with periodontitis have serum antibodies to oral Gram positive bacteria that are cross-reactive with epithelial antigens. In the present report cross-reactive epithelial antigens including CD24, lactate dehydrogenase A [LDM-A], antioxidant protein 2 [AOP 2] and nuclear factor of activated T cells 5 [NFAT 5], were identified by screening a cDNA expression library with pooled patient sera. Titres of antibodies to CD24 peptide correlated negatively with indices of periodontal disease severity. Strong expression of CD24 in the reactive periodontal epithelium and inflamed gingival attachment contrasted with low to undetectable expression in the external gingival epithelium. In periodontitis, a local action of these auto-reactive antibodies could modulate the regulatory potential associated with expression of CD24 in this epithelium.
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Affiliation(s)
- P Ye
- Institute of Dental Research, Westmead Millennium Institute and Westmead Centre for Oral Health, Westmead, NSW, Australia
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313
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Duque J, Fresno M, Iñiguez MA. Expression and Function of the Nuclear Factor of Activated T Cells in Colon Carcinoma Cells. J Biol Chem 2005; 280:8686-93. [PMID: 15632146 DOI: 10.1074/jbc.m413076200] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Increasing evidence shows a crucial role of the Ca2+/ calcineurin-mediated activation of the nuclear factor of activated T cells (NFAT) in the regulation of a variety of processes in nonimmune cells. Here we provide evidence that NFATc1 and NFATc2 are expressed in human colon carcinoma cell lines. These proteins are translocated from the cytoplasm to the nucleus upon treatment with a combination of phorbol 12-myristate 13-acetate plus the calcium ionophore A23187. Subsequent to translocation to the nucleus, NFATc1 and NFATc2 were able to bind to a NFAT response element in the DNA, regulating transcriptional activation of genes containing a NFAT-responsive element such as cyclooxygenase-2 (COX-2). COX-2 expression and prostaglandin E2 (PGE2) production were induced upon pharmacological stimuli leading to NFAT activation and blunted by inhibition of calcineurin phosphatase with cyclosporin A or tacrolimus (FK506). Expression of NFAT wild type protein or the active catalytic subunit of calcineurin transactivates COX-2 promoter activity, whereas a dominant negative mutant of NFAT inhibited COX-2 induction in colon carcinoma cell lines. Furthermore, mutation or deletion of NFAT binding sites in the human COX-2 promoter greatly diminished its induction by phorbol 12-myristate 13-acetate/calcium ionophore A23187. These findings demonstrate the presence and activation of NFAT in human colon carcinoma cells, with important implications in the regulation of genes involved in the transformed phenotype as COX-2.
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Affiliation(s)
- Javier Duque
- Centro de Biología Molecular Severo Ochoa, Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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314
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Skubitz KM, Cheng EY, Clohisy DR, Thompson RC, Skubitz APN. Gene expression in giant-cell tumors. ACTA ACUST UNITED AC 2004; 144:193-200. [PMID: 15514587 DOI: 10.1016/j.lab.2004.06.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Malignant transformation is thought to be associated with changes in the expression of a number of genes, and this alteration in gene expression is considered critical to the development of the malignant phenotype. In this study, gene expression in 8 samples of giant-cell tumor (GCT) of bone, as well as in bone at the site of osteoarthritis and in a variety of normal tissues, was determined at Gene Logic Inc (Gaithersburg, Md) with the use of Affymetrix GeneChip U_133 arrays containing approximately 40,000 genes/expressed sequence tags (ESTs). Gene-expression analysis was performed with the use of the Gene Logic GeneExpress Software System. Differences in gene expression between GCTs and bone were observed. In addition, genes expressed uniquely in GCTs among these and 519 samples from 20 other tissue types were identified. Some of the genes that were found to be overexpressed in GCTs, such as tartrate-resistant acid phosphatase and the lysosomal H + -transporting ATPase, are also expressed by osteoclasts. Osteoprotegrin ligand (OPGL) was also selectively overexpressed in GCTs. The genes found to be overexpressed in GCTs appear to reflect the genetic profile of osteoclast-lineage cells and also the genetic profile of an osteoclastogenic environment. The genes identified in this study may play a role in the pathogenesis of GCTs, confirm the likely importance of OPGL in GCT pathogenesis, and may indicate other possible targets to which antitumor therapy could be directed.
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Affiliation(s)
- Keith M Skubitz
- Department of Medicine, University of Minnesota Medical School, Minneapolis, USA.
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315
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Alfonso-Jaume MA, Mahimkar R, Lovett DH. Co-operative interactions between NFAT (nuclear factor of activated T cells) c1 and the zinc finger transcription factors Sp1/Sp3 and Egr-1 regulate MT1-MMP (membrane type 1 matrix metalloproteinase) transcription by glomerular mesangial cells. Biochem J 2004; 380:735-47. [PMID: 14979875 PMCID: PMC1224202 DOI: 10.1042/bj20031281] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2003] [Revised: 02/06/2004] [Accepted: 02/23/2004] [Indexed: 01/17/2023]
Abstract
The transition of normally quiescent glomerular MCs (mesangial cells) to a highly proliferative phenotype with characteristics of myofibroblasts is a process commonly observed in inflammatory diseases affecting the renal glomerulus, the ultimate result of which is glomerulosclerosis. Generation of proteolytically active MMP (matrix metalloproteinase)-2 by the membrane-associated membrane type 1 (MT1)-MMP is responsible for the transition of mesangial cells to the myofibroblast phenotype [Turck, Pollock, Lee, Marti and Lovett (1996) J. Biol. Chem. 271, 15074-15083]. In the present study, we show that the expression of MT1-MMP within the context of MCs is mediated by three discrete cis -acting elements: a proximal non-canonical Sp1 site that preferentially binds Sp1; an overlapping Sp1/Egr-1-binding site that preferentially binds Egr-1; and a more distal binding site for the NFAT (nuclear factor of activated T cells) that binds the NFAT c1 isoform present in MC nuclear extracts. Transfection with an NFAT c1 expression plasmid, or activation of calcineurin with a calcium ionophore, yielded major increases in NFAT c1 nuclear DNA-binding activity, MT1-MMP transcription and protein synthesis, which were additive with the lower levels of transactivation provided by the proximal Sp1 and the overlapping Sp1/Egr-1 sites. Specific binding of NFAT c1 to the MT1-MMP promoter was confirmed by chromatin immunoprecipitation studies, while MT1-MMP expression was suppressed by treatment with the calcineurin inhibitor, cyclosporin A. These studies are the first demonstration that a specific NFAT isoform enhances transcription of an MMP (MT1-MMP) that plays a major role in the proteolytic events that are a dominant feature of acute glomerular inflammation. Suppression of MT1-MMP by commonly used calcineurin inhibitors may play a role in the development of renal fibrosis following renal transplantation.
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Affiliation(s)
- Maria Alejandra Alfonso-Jaume
- The Department of Medicine, San Francisco VAMC/University of California, 111J Medical Service, 4150 Clement Street, San Francisco, CA 94121, USA
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316
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Liu Z, Dronadula N, Rao GN. A Novel Role for Nuclear Factor of Activated T Cells in Receptor Tyrosine Kinase and G Protein-coupled Receptor Agonist-induced Vascular Smooth Muscle Cell Motility. J Biol Chem 2004; 279:41218-26. [PMID: 15272006 DOI: 10.1074/jbc.m406917200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In addition to their role in cytokine gene regulation in T cells, nuclear factors of activated T cells (NFATs) have been shown to be involved in cardiac development and hypertrophy. We have reported previously that NFATs play an important role in the regulation of vascular smooth muscle cell (VSMC) proliferation by receptor tyrosine kinase (RTK) and G protein-coupled receptor (GPCR) agonists, platelet-derived growth factor-BB (PDGF-BB) and thrombin, respectively. To understand the role of NFATs in vascular disease and development, we have now studied the role of these transcriptional factors in VSMC motility. PDGF-BB and thrombin induced VSMC motility in a dose-dependent manner. Blockade of NFAT activation resulted in substantial reduction in PDGF-BB- and thrombin-induced VSMC motility. PDGF-BB and thrombin also induced interleukin-6 (IL-6) expression in NFAT-dependent manner. Furthermore, IL-6 dose-dependently caused VSMC motility. A neutralizing anti-rat IL-6 antibody inhibited VSMC motility induced by IL-6, PDGF-BB, and thrombin. In addition, exogenous addition of IL-6 rescued both PDGF-BB- and thrombin-induced VSMC motility from inhibition by the blockade of NFAT activation. Together, these results for the first time demonstrate that NFATs mediate both RTK and GPCR agonist-induced VSMC motility via induction of expression of IL-6.
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Affiliation(s)
- Zhimin Liu
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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317
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Zaichuk TA, Shroff EH, Emmanuel R, Filleur S, Nelius T, Volpert OV. Nuclear factor of activated T cells balances angiogenesis activation and inhibition. ACTA ACUST UNITED AC 2004; 199:1513-22. [PMID: 15184502 PMCID: PMC2211785 DOI: 10.1084/jem.20040474] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
It has been demonstrated that vascular endothelial cell growth factor (VEGF) induction of angiogenesis requires activation of the nuclear factor of activated T cells (NFAT). We show that NFATc2 is also activated by basic fibroblast growth factor and blocked by the inhibitor of angiogenesis pigment epithelial–derived factor (PEDF). This suggests a pivotal role for this transcription factor as a convergence point between stimulatory and inhibitory signals in the regulation of angiogenesis. We identified c-Jun NH2-terminal kinases (JNKs) as essential upstream regulators of NFAT activity in angiogenesis. We distinguished JNK-2 as responsible for NFATc2 cytoplasmic retention by PEDF and JNK-1 and JNK-2 as mediators of PEDF-driven NFAT nuclear export. We identified a novel NFAT target, caspase-8 inhibitor cellular Fas-associated death domain–like interleukin 1β–converting enzyme inhibitory protein (c-FLIP), whose expression was coregulated by VEGF and PEDF. Chromatin immunoprecipitation showed VEGF-dependent increase of NFATc2 binding to the c-FLIP promoter in vivo, which was attenuated by PEDF. We propose that one possible mechanism of concerted angiogenesis regulation by activators and inhibitors may be modulation of the endothelial cell apoptosis via c-FLIP controlled by NFAT and its upstream regulator JNK.
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Affiliation(s)
- Tetiana A Zaichuk
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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318
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Holzmann K, Kohlhammer H, Schwaenen C, Wessendorf S, Kestler HA, Schwoerer A, Rau B, Radlwimmer B, Döhner H, Lichter P, Gress T, Bentz M. Genomic DNA-chip hybridization reveals a higher incidence of genomic amplifications in pancreatic cancer than conventional comparative genomic hybridization and leads to the identification of novel candidate genes. Cancer Res 2004; 64:4428-33. [PMID: 15231651 DOI: 10.1158/0008-5472.can-04-0431] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Genomic analyses aimed at the detection of high-level DNA amplifications were performed on 13 widely used pancreatic cancer cell lines and 6 pancreatic tumor specimens. For these analyses, array-based comparative genomic hybridization (Matrix-CGH) onto dedicated microarrays was used. In comparison with chromosomal CGH (eight amplifications), a >3-fold number of DNA amplifications was detected (n = 29). The most frequent amplifications mapped to 7p12.3 (three pancreatic cancer cell lines and three pancreatic tumor specimens), 8q24 (four pancreatic cancer cell lines and one pancreatic tumor specimen), 11q13 (three pancreatic cancer cell lines and three pancreatic tumor specimens), and 20q13 (four pancreatic cancer cell lines and three pancreatic tumor specimens). Genes contained in the consensus regions were MYC (8q24), EGFR (7p12.3), and FGF3 (11q13). In six of seven pancreatic cancer cell lines and pancreatic tumor specimens with 20q13 amplifications, the novel candidate gene NFAT C2, which plays a role in the activation of cytokines, was amplified. Other amplifications also affected genes for which a pathogenetic role in pancreatic carcinoma has not been described, such as BCL10 and BCL6, two members of the BCL family. A subset of amplified genes was checked for overexpression by means of real-time PCR, revealing the highest expression levels for BCL6 and BCL10. Thus, Matrix-CGH allows the detection of a high number of amplifications, resulting in the identification of novel candidate genes in pancreatic cancer.
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319
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Saito K, Muto T, Tomimori Y, Maruoka H, Tanaka T, Fukuda Y. Human chymase stimulates Ca2+ signaling in human polymorphonuclear cells. Immunol Lett 2004; 89:161-5. [PMID: 14556974 DOI: 10.1016/s0165-2478(03)00129-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Human chymase is known to function as a chemoattractant for human leukocytes. To investigate the mechanism of the chymase-induced cell migration, change in intracellular calcium concentration ([Ca(2+)]i) was examined in human polymorphonuclear (PMN) cells using Fluo-3 as a fluorescent Ca(2+) indicator. Treatment of PMN cells with human chymase caused [Ca(2+)]i elevation in a concentration-dependent manner. Depletion of extracellular Ca(2+) from the medium partially attenuated the chymase-induced [Ca(2+)]i increase, showing that both Ca(2+) influx and Ca(2+) release from internal stores might be involved in the [Ca(2+)]i response. Pretreatment of the cells with pertussis toxin completely blocked the chymase-induced [Ca(2+)]i signal, suggesting an involvement of G protein in the chymase-mediated [Ca(2+)]i elevation. The data in the present study raise the possibility that the chymase-induced cell migration is mediated by the [Ca(2+)]i elevation, which might be caused by stimulation of a G-protein-coupled receptor such as protease-activated receptors (PARs).
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Affiliation(s)
- Kayo Saito
- Suntory Biomedical Research Limited, 1-1-1 Wakayamadai, Shimamoto-cho, Mishima-gun, 618-8503, Osaka, Japan
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320
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Chung J, Yoon SO, Lipscomb EA, Mercurio AM. The Met receptor and alpha 6 beta 4 integrin can function independently to promote carcinoma invasion. J Biol Chem 2004; 279:32287-93. [PMID: 15161909 DOI: 10.1074/jbc.m403809200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
It has been proposed that a constitutive, physical association of the Met receptor and the alpha(6)beta(4) integrin exists on the surface of invasive carcinoma cells and that hepatocyte growth factor (HGF)-mediated invasion is dependent on alpha(6)beta(4) (Trusolino, L., Bertotti, A., and Comoglio, P. M. (2001) Cell 107, 643-654). The potential significance of these results prompted us to re-examine this hypothesis. Using three different carcinoma cell lines that express both Met and alpha(6)beta(4), we were unable to detect the constitutive association of these receptors by co-immunoprecipitation. Moreover, carcinoma cells that lacked expression of alpha(6)beta(4) exhibited Met-dependent invasion toward HGF, and increasing Met expression by viral infection of these cells enhanced invasion without inducing alpha(6)beta(4) expression. Although expression of alpha(6)beta(4) in such cells enhanced their invasion to HGF, it also enhanced their ability to invade toward other chemoattractants such as lysophosphatidic acid, and this latter invasion was not inhibited by a function-blocking Met antibody. Finally, depletion of beta(4) by RNA interference in invasive carcinoma cells that express both receptors reduced the ability of these cells to invade toward HGF by approximately 25%, but it did not abrogate their invasion. These data argue that the invasive function of Met can be independent of alpha(6)beta(4) and that alpha(6)beta(4) has a generic influence on the invasion of carcinoma cells that is not specific to Met.
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Affiliation(s)
- Jun Chung
- Division of Cancer Biology and Angiogenesis, Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
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321
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Ayers M, Symmans WF, Stec J, Damokosh AI, Clark E, Hess K, Lecocke M, Metivier J, Booser D, Ibrahim N, Valero V, Royce M, Arun B, Whitman G, Ross J, Sneige N, Hortobagyi GN, Pusztai L. Gene expression profiles predict complete pathologic response to neoadjuvant paclitaxel and fluorouracil, doxorubicin, and cyclophosphamide chemotherapy in breast cancer. J Clin Oncol 2004; 22:2284-93. [PMID: 15136595 DOI: 10.1200/jco.2004.05.166] [Citation(s) in RCA: 427] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE The goal of this study was to examine the feasibility of developing a multigene predictor of pathologic complete response (pCR) to sequential weekly paclitaxel and fluorouracil + doxorubicin + cyclophosphamide (T/FAC) neoadjuvant chemotherapy regimen for breast cancer. PATIENTS AND METHODS All patients underwent one-time pretreatment fine-needle aspiration to obtain RNA from the cancer for transcriptional profiling using cDNA arrays containing 30721 human sequence clones. Analysis was performed after profiling, and 42 patients' clinical results were available, 24 of which were used for predictive marker discovery; 18 patients' results were used as an independent validation set. RESULTS Thirty-one percent of patients had pCR (six discovery and seven validation), defined as disappearance of all invasive cancer in the breast after completion of chemotherapy. We could identify no single marker that was sufficiently associated with pCR to be used as an individual predictor. A multigene model with 74 markers (P <or=.09) was built using data from the discovery samples and tested on the validation samples. Overall, a 78% (14 of 18) predictive accuracy was observed, with a 100% (three of three) positive predictive value for pCR, a 73% (11 of 15) negative predictive value, a sensitivity of 43% (three of seven), and a specificity of 100% (11 of 11). The expected response rate to T/FAC neoadjuvant therapy in unselected patients is 28%. CONCLUSION Our results suggest that transcriptional profiling has the potential to identify a gene expression pattern in breast cancer that may lead to clinically useful predictors of pCR to T/FAC neoadjuvant therapy.
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Affiliation(s)
- M Ayers
- Millennium Pharmaceuticals Inc, Cambridge, MA, USA
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322
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Fosmire SP, Dickerson EB, Scott AM, Bianco SR, Pettengill MJ, Meylemans H, Padilla M, Frazer-Abel AA, Akhtar N, Getzy DM, Wojcieszyn J, Breen M, Helfand SC, Modiano JF. Canine malignant hemangiosarcoma as a model of primitive angiogenic endothelium. J Transl Med 2004; 84:562-72. [PMID: 15064773 DOI: 10.1038/labinvest.3700080] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Hemangiosarcoma (HSA) is a common untreatable cancer of dogs that resembles human angiosarcoma. Detailed studies of these diseases have been historically hindered by the paucity of suitable reagents. Here, we show that expression of CD117 (c-Kit) can distinguish primitive (malignant) from mature (benign) proliferative endothelial lesions, and we describe eight independent cell lines derived from canine HSA explants. Endothelial origin was confirmed by sustained expression of surface CD105 (endoglin), CD146 (MUC18), and CD51/CD61 (alpha(v)beta(3) integrin). The cell lines showed anchorage-independent growth and were motile and invasive when cultured on a basement membrane matrix. They required endothelial growth factors for growth and survival, and they could be induced to form tubular structures resembling blood vessels when cultured under low calcium conditions. The formation of vessel-like structures was blocked by nicotine, and restored by FK506, suggesting that 'nuclear factor of activated T cells' activity prevents differentiation of these cells. In summary, these cell lines represent a unique and novel resource to improve our understanding of endothelial cell biology in general and canine HSA in particular.
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Affiliation(s)
- Susan P Fosmire
- AMC Cancer Research Center and Integrated Department of Immunology, University of Colorado Health Sciences Center, Denver, 80214, USA
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323
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López-Rodríguez C, Antos CL, Shelton JM, Richardson JA, Lin F, Novobrantseva TI, Bronson RT, Igarashi P, Rao A, Olson EN. Loss of NFAT5 results in renal atrophy and lack of tonicity-responsive gene expression. Proc Natl Acad Sci U S A 2004; 101:2392-7. [PMID: 14983020 PMCID: PMC356961 DOI: 10.1073/pnas.0308703100] [Citation(s) in RCA: 209] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The transcription factor NFAT5/TonEBP, a member of the NFAT/Rel family of transcription factors, has been implicated in diverse cellular responses, including the response to osmotic stress, integrin-dependent cell migration, T cell activation, and the Ras pathway in Drosophila. To clarify the in vivo role of NFAT5, we generated NFAT5-null mice. Homozygous mutants were genetically underrepresented after embryonic day 14.5. Surviving mice manifested a progressive and profound atrophy of the kidney medulla with impaired activation of several osmoprotective genes, including those encoding aldose reductase, Na+/Cl--coupled betaine/gamma-aminobutyric acid transporter, and the Na+/myo-inositol cotransporter. The aldose reductase gene is controlled by a tonicity-responsive enhancer, which was refractory to hypertonic stress in fibroblasts lacking NFAT5, establishing this enhancer as a direct transcriptional target of NFAT5. Our findings demonstrate a central role for NFAT5 as a tonicity-responsive transcription factor required for kidney homeostasis and function.
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Affiliation(s)
- Cristina López-Rodríguez
- Department of Pathology, Harvard Medical School and Center for Blood Research, Institute for Biomedical Research, 200 Longwood Avenue, Boston MA 02115, USA
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324
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Wang H, Fu W, Im JH, Zhou Z, Santoro SA, Iyer V, DiPersio CM, Yu QC, Quaranta V, Al-Mehdi A, Muschel RJ. Tumor cell alpha3beta1 integrin and vascular laminin-5 mediate pulmonary arrest and metastasis. J Cell Biol 2004; 164:935-41. [PMID: 15024036 PMCID: PMC2172296 DOI: 10.1083/jcb.200309112] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2003] [Accepted: 02/10/2004] [Indexed: 11/22/2022] Open
Abstract
Arrest of circulating tumor cells in distant organs is required for hematogenous metastasis, but the tumor cell surface molecules responsible have not been identified. Here, we show that the tumor cell alpha3beta1 integrin makes an important contribution to arrest in the lung and to early colony formation. These analyses indicated that pulmonary arrest does not occur merely due to size restriction, and raised the question of how the tumor cell alpha3beta1 integrin contacts its best-defined ligand, laminin (LN)-5, a basement membrane (BM) component. Further analyses revealed that LN-5 is available to the tumor cell in preexisting patches of exposed BM in the pulmonary vasculature. The early arrest of tumor cells in the pulmonary vasculature through interaction of alpha3beta1 integrin with LN-5 in exposed BM provides both a molecular and a structural basis for cell arrest during pulmonary metastasis.
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Affiliation(s)
- Hui Wang
- Dept. of Pathology, Rm. 916D ARC, Children's Hospital of Philadelphia, 3615 Civic Center Blvd., Philadelphia, PA 19104, USA
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325
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Yamaguchi K, Itoh K, Ohnishi N, Itoh Y, Baum C, Tsuji T, Nagao T, Higashitsuji H, Okanoue T, Fujita J. Engineered long terminal repeats of retroviral vectors enhance transgene expression in hepatocytes in vitro and in vivo. Mol Ther 2004; 8:796-803. [PMID: 14599813 DOI: 10.1016/j.ymthe.2003.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
To analyze the important elements for retroviral expression in hepatocytes, cis-acting elements in the U3 region of the long terminal repeat (LTR) of the polycythemic strain of spleen focus-forming virus (SFFVp) were analyzed in a hepatocellular carcinoma cell line. Two cis-acting elements located within the upstream region of the direct repeat, which positively regulated retroviral expression, were identified. Transcription factors NFAT5 and Sp1, which are ubiquitously expressed in a variety of tissues, bound to these elements. To increase specificity without lowering the potency of retroviral expression in hepatocytes, these elements were replaced by a sequence derived from the hepatitis B virus enhancer II region. Novel vectors, SF-Hep3 and SF-Hep5 (SFFVp-based vector for hepatocytes 3 and 5), were developed with these engineered LTRs. The engineered LTRs of these vectors enhanced the retroviral expression only in hepatocellular carcinoma cell lines in vitro. These vectors also increased transgene expression 4- to 9-fold or 3.5- to 5-fold in comparison with a Moloney murine leukemia virus-based vector or a vector containing the wild-type LTR of SFFVp, respectively, in murine hepatocytes in vivo.
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Affiliation(s)
- Kanji Yamaguchi
- Department of Clinical Molecular Biology, Faculty of Medicine, Kyoto University, 606-8507, Kyoto, Japan
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326
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Escher R, Jones A, Hagos F, Carmichael C, Horwitz M, Olopade OI, Scott HS. Chromosome band 16q22-linked familial AML: Exclusion of candidate genes, and possible disease risk modification byNQO1 polymorphisms. Genes Chromosomes Cancer 2004; 41:278-82. [PMID: 15334552 DOI: 10.1002/gcc.20084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Analyses of chromosomal translocation and inversion breakpoints in sporadic acute myeloid leukemias have identified many transcription factors as playing a role in leukemogenesis. Studies of families with a Mendelian predisposition to hematological malignancies have identified the gene coding for the transcription factor RUNX1 as a leukemia-predisposing gene involved in the first steps of leukemogenesis. Using two families, another autosomal dominant familial leukemia locus was linked to chromosome band 16q22 where the CBFB gene maps. Although CBFB forms a core-binding factor transcriptional complex with RUNX1, previous analyses have excluded the CBFB gene as the leukemia-predisposing gene in these families. In the current study, we performed an extended molecular analysis in these families of the four other transcription factor genes in the 16q22 critical region as well as of two other genes with a known association with leukemia. Several previously undescribed but nonpathogenic sequence variants were identified. We demonstrated that the transcription factors E2F4, CTCF, NFATC3, and NFAT5, and the genes coding for NAD(P)H:quinone oxido-reductase 1 (NQO1) and for E-cadherin are not responsible for the leukemia susceptibility in these families. The presence of NQO1 polymorphisms may suggest a role for this gene in disease risk modification in these families.
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Affiliation(s)
- Robert Escher
- Genetics and Bioinformatics Division, the Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
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327
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Lipscomb EA, Dugan AS, Rabinovitz I, Mercurio AM. Use of RNA interference to inhibit integrin (alpha6beta4)-mediated invasion and migration of breast carcinoma cells. Clin Exp Metastasis 2003; 20:569-76. [PMID: 14598892 DOI: 10.1023/a:1025819521707] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The application of small interfering RNA (siRNA) oligonucleotides to silence gene expression has profound implications for the intervention of human diseases including cancer. Using this technique, we explored the possibility that the alpha6beta4 integrin, a laminin adhesion receptor with a recognized role in the invasive phenotype of many carcinomas, represents a potential therapeutic target to inhibit the migration and invasion of carcinoma cells. We found that siRNA oligonucleotides targeted to either subunit of the alpha6beta4 integrin reduced cell surface expression of this integrin and resulted in decreased invasion of MDA-MB-231 breast carcinoma cells. Interestingly, reduced alpha6beta4 expression also promoted decreased migration on non-laminin substrata indicating that this integrin can function in a ligand-independent manner. In addition, the absence of beta4 expression in these cells augmented the formation of alpha6beta1 heterodimers and increased adhesion to laminin-1. Taken together, these results substantiate the importance of the alpha6beta4 integrin in invasion and migration that has been demonstrated previously by expression of the beta4 subunit in beta4-deficient cell lines and by function blocking antibodies. Furthermore, these data suggest that the utilization of siRNA oligonucleotides to reduce the expression of the alpha6beta4 integrin may be a useful approach to prevent carcinoma cell progression.
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Affiliation(s)
- Elizabeth A Lipscomb
- Division of Cancer Biology and Angiogenesis, Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA
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328
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Lee SD, Colla E, Sheen MR, Na KY, Kwon HM. Multiple domains of TonEBP cooperate to stimulate transcription in response to hypertonicity. J Biol Chem 2003; 278:47571-7. [PMID: 12970349 DOI: 10.1074/jbc.m308795200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tonicity-responsive enhancer binding protein (TonEBP), also known as NFAT5, belongs to the Rel family of transcriptional activators. In the kidney medulla and thymus, TonEBP plays a major role in protecting renal cells and T cells from the deleterious effects of ambient hypertonicity. TonEBP is stimulated by hypertonicity via several pathways: increased expression of protein, nuclear translocation, and increased transactivation. In this study, we identified five domains of TonEBP involved in transactivation. The two conserved glutamine repeats were not involved in transactivation. There were three activation domains that could stimulate transcription independently. In addition, there were two modulation domains that potentiated the activity of the activation domains. One of the activation domains is unique to a splice isoform that is more active than others, indicating that alternative splicing can affect the activity of TonEBP. Another activation domain and one of the modulation domains were stimulated by hypertonicity. All the five domains acted in synergy in every combination. Although overall phosphorylation of TonEBP increased in response to hypertonicity, phosphorylation of the activation and modulation domains did not increase in isolation. In sum, TonEBP possesses far more elaborate domains involved in transactivation compared with other Rel proteins.
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Affiliation(s)
- Sang Do Lee
- Department of Medicine, University of Maryland, Baltimore, Maryland 21201, USA
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329
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Zhang Z, Ferraris JD, Brooks HL, Brisc I, Burg MB. Expression of osmotic stress-related genes in tissues of normal and hyposmotic rats. Am J Physiol Renal Physiol 2003; 285:F688-93. [PMID: 12824075 DOI: 10.1152/ajprenal.00028.2003] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
TonEBP is a transcription factor that, when activated by hypertonicity, increases transcription of genes, including those involved in organic osmolyte accumulation. Surprisingly, it is expressed in virtually all tissues, including many never normally exposed to hypertonicity. We measured TonEBP mRNA (real-time PCR) and protein (Western blot analysis) in tissues of control (plasma osmolality 294 +/- 1 mosmol/kgH2O) and hyposmotic (dDAVP infusion plus water loading for 3 days, 241 +/- 2 mosmol/kgH2O) rats to test whether the ubiquitous expression of TonEBP mRNA is osmotically regulated around the normal plasma osmolality. TonEBP protein is reduced by hyposmolality in thymus and liver, but not in brain, and is not detected in heart and skeletal muscle. TonEBP mRNA decreases in brain and liver but is unchanged in other tissues. There are no general changes in mRNA of TonEBP-mediated genes: aldose reductase (AR) does not change in any tissue, betaine transporter (BGT1) decreases only in liver, taurine transporter (TauT) only in brain and thymus, and inositol transporter (SMIT) only in skeletal muscle and liver. Heat shock protein (Hsp)70-1 and Hsp70-2 mRNA increase greatly in most tissues, which cannot be attributed to decreased TonEBP activity. The conclusions are as follows: 1) TonEBP protein or mRNA expression is reduced by hyposmolality in thymus, liver, and brain. 2) TonEBP protein and mRNA expression are differentially regulated in some tissues. 3) Although AR, SMIT, BGT1, and TauT are regulated by TonEBP in renal medullary cells, other sources of regulation may predominate in other tissues. 4) TonEBP abundance and activity are regulated by factors other than tonicity in some tissues.
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Affiliation(s)
- Zheng Zhang
- Laboratory of Kidney and Electrolyte Metabolism, National Heart Lung and Blood Institute, Bethesda, MD 20892, USA.
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330
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Hogan PG, Chen L, Nardone J, Rao A. Transcriptional regulation by calcium, calcineurin, and NFAT. Genes Dev 2003; 17:2205-32. [PMID: 12975316 DOI: 10.1101/gad.1102703] [Citation(s) in RCA: 1504] [Impact Index Per Article: 71.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Patrick G Hogan
- The Center for Blood Research, Harvard Medical School, Boston, Massachusetts 02115, USA
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331
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Abstract
NFAT5/TonEBP, the most recently described member of the rel/NFkappaB/NFAT family of signal-dependent transcription factors, is activated by extracellular hypertonicity-a cellular stress of particular and perhaps unique physiologic relevance to cells of the renal medulla. Accumulating evidence suggests that NFAT5/TonEBP also functions in vivo under isotonic conditions as part of a ubiquitous regulatory mechanism that senses and adjusts available intracellular volume during cell growth to establish an intracellular environment appropriate for optimal cell proliferation.
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Affiliation(s)
- Steffan N Ho
- Department of Pathology, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0644, USA.
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332
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Neal JW, Clipstone NA. A constitutively active NFATc1 mutant induces a transformed phenotype in 3T3-L1 fibroblasts. J Biol Chem 2003; 278:17246-54. [PMID: 12598522 DOI: 10.1074/jbc.m300528200] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The calcineurin/nuclear factor of activated T cells (NFAT) signaling pathway is best known for its role in T lymphocyte activation. However, it has become increasingly apparent that this signaling pathway is also involved in the regulation of cell growth and development in a wide variety of different tissues and cell types. Here we have investigated the effects of sustained NFATc1 signaling on the growth and differentiation of the murine 3T3-L1 preadipocyte cell line. Remarkably, we find that expression of a constitutively active NFATc1 mutant (caNFATc1) in these immortalized cells inhibits their differentiation into mature adipocytes and causes them to adopt a transformed cell phenotype, including loss of contact-mediated growth inhibition, reduced serum growth requirements, protection from growth factor withdrawal-induced apoptosis, and formation of colonies in semisolid media. Furthermore, we find that caNFATc1-expressing cells acquire growth factor autonomy and are able to proliferate even in the complete absence of serum. We provide evidence that this growth factor independence is caused by the NFATc1-dependent production of a soluble heat-labile autocrine factor that is capable of promoting the growth and survival of wild type 3T3-L1 cells as well as potently inhibiting their differentiation into mature adipocytes. Finally, we demonstrate that cells expressing caNFATc1 form tumors in nude mice. Taken together, these results indicate that deregulated NFATc1 activity is able to induce the immortalized 3T3-L1 preadipocyte cell line to acquire the well established hallmarks of cellular transformation and thereby provide direct evidence for the oncogenic potential of the NFATc1 transcription factor.
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Affiliation(s)
- Joel W Neal
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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333
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Na KY, Woo SK, Lee SD, Kwon HM. Silencing of TonEBP/NFAT5 transcriptional activator by RNA interference. J Am Soc Nephrol 2003; 14:283-8. [PMID: 12538727 DOI: 10.1097/01.asn.0000045050.19544.b2] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
TonEBP is a transcriptional activator that is expressed throughout development in many tissues and cell types. In the kidney medulla, TonEBP appears to be an important local regulator of differentiation by virtue of stimulating several genes. To study the function of TonEBP, two small interfering RNA (siRNA) duplexes were developed that reduced TonEBP expression effectively via RNA interference. The silencing lasted only 3 d after introduction of the TonEBP-siRNA's. As expected, TonEBP-driven reporter gene expression and expression of the sodium/myo-inositol cotransproter (SMIT), aldose reductase (AR) and heat shock protein 70 (HSP70) mRNA were significantly decreased in cells where TonEBP expression was silenced. These data provide direct evidence that the SMIT, AR, and HSP70 genes are targets of TonEBP, although the potential role of other proteins, such as accessory proteins, cannot be excluded. The TonEBP-siRNA is an effective tool that should prove useful in the investigation of loss-of-function relationship in cells.
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Affiliation(s)
- Ki Young Na
- Division of Nephrology, Johns Hopkins University, Baltimore, Maryland, USA
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334
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Ferraris JD, Persaud P, Williams CK, Chen Y, Burg MB. cAMP-independent role of PKA in tonicity-induced transactivation of tonicity-responsive enhancer/ osmotic response element-binding protein. Proc Natl Acad Sci U S A 2002; 99:16800-5. [PMID: 12482947 PMCID: PMC139224 DOI: 10.1073/pnas.222659799] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2002] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Hypertonicity-induced increase in activity of the transcription factor tonicity-responsive enhancer/osmotic response element-binding protein (TonEBP/OREBP) protects renal cells by increasing transcription of genes, including those involved in increased accumulation of organic osmolytes. We previously showed that hypertonicity increases transactivating activity of TonEBP/OREBP. Assay with a binary GAL4 transactivation system showed that the 984 C-terminal amino acids of TonEBP/OREBP (amino acids 548-1531) contain a tonicity-dependent transactivation domain (TAD). Also, amino acids 548-1531 undergo tonicity-dependent phosphorylation, and some inhibitors of protein kinases reduce the tonicity-dependent transactivation. In the present studies we examined the role of protein kinase A (PKA). RESULTS (i) An inhibitor of PKA (H89) reduces tonicity-dependent increases in transactivation, ORE/TonE reporter activity, and induction of aldose reductase and betaine transporter mRNAs. (ii) Overexpression of the catalytic subunit of PKA (PKAc) increases transactivation activity of amino acids 548-1531 and activity of an ORE/TonE reporter. The increases are much greater under isotonic than under hypertonic conditions. (iii) A dominant-negative PKAc reduces activity of an ORE/TonE reporter. (iv) PKAc activity increases with tonicity but cAMP does not. (v) TonEBP/OREBP and PKAc coimmunoprecipitate. (vi) amino acids 872-1271, including N- and C-terminal polyglutamine stretches, demonstrate tonicity-dependent transactivation, albeit less than amino acids 548-1531, and a similar role for PKA. CONCLUSIONS (i) PKA plays an important role in TonEBP/OREBP activation of tonicity-dependent gene expression; (ii) PKA activation of TonEBP/OREBP appears to be cAMP-independent; and (iii) amino acids 872-1271 are sufficient for tonicity-dependent transactivation of TonEBP/OREBP.
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Affiliation(s)
- Joan D Ferraris
- Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.
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