701
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Ju X, Katiyar S, Wang C, Liu M, Jiao X, Li S, Zhou J, Turner J, Lisanti MP, Russell RG, Mueller SC, Ojeifo J, Chen WS, Hay N, Pestell RG. Akt1 governs breast cancer progression in vivo. Proc Natl Acad Sci U S A 2007; 104:7438-43. [PMID: 17460049 PMCID: PMC1863437 DOI: 10.1073/pnas.0605874104] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The serine threonine kinase Akt1 has been implicated in the control of cellular metabolism, survival and growth. Here, disruption of the ubiquitously expressed member of the Akt family of genes, Akt1, in the mouse demonstrates a requirement for Akt1 in ErbB2-induced mammary tumorigenesis. Akt1 deficiency delayed tumor growth and reduced lung metastases, correlating with a reduction in phosphorylation of the Akt1 target, tuberous sclerosis 2 (TSC2) at Ser-939. Akt1-deficient mammary epithelial tumor cells (MEC) were reduced in size and proliferative capacity, with reduced cyclin D1 and p27(KIP1) abundance. Akt1 deficiency abrogated the oncogene-induced changes in polarization of MEC in three-dimensional culture and reverted oncogene-induced relocalization of the phosphorylated ezrin-radixin-moesin proteins. Akt1 increased MEC migration across an endothelial cell barrier, enhancing the persistence of migratory directionality. An unbiased proteomic analysis demonstrated Akt1 mediated MEC migration through paracrine signaling via induction of expression and secretion of CXCL16 and MIP1gamma. Akt1 governs MEC polarity, migratory directionality and breast cancer onset induced by ErbB2 in vivo.
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Affiliation(s)
| | | | - Chenguang Wang
- Departments of *Cancer Biology and
- Medical Oncology, Kimmel Cancer Center, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA 19107
| | | | | | | | - Jie Zhou
- Departments of *Cancer Biology and
| | - Jacob Turner
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Research Building, 3970 Reservoir Road NW, Washington, DC 20057; and
| | | | - Robert G. Russell
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Research Building, 3970 Reservoir Road NW, Washington, DC 20057; and
| | - Susette C. Mueller
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Research Building, 3970 Reservoir Road NW, Washington, DC 20057; and
| | - John Ojeifo
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Research Building, 3970 Reservoir Road NW, Washington, DC 20057; and
| | - William S. Chen
- Department of Biochemistry and Molecular Genetics, M/C 669, University of Illinois at Chicago, 900 South Ashland, Chicago, IL 60607
| | - Nissim Hay
- Department of Biochemistry and Molecular Genetics, M/C 669, University of Illinois at Chicago, 900 South Ashland, Chicago, IL 60607
| | - Richard G. Pestell
- Departments of *Cancer Biology and
- Medical Oncology, Kimmel Cancer Center, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA 19107
- To whom correspondence should be addressed. E-mail:
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702
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Fang D, Hawke D, Zheng Y, Xia Y, Meisenhelder J, Nika H, Mills GB, Kobayashi R, Hunter T, Lu Z. Phosphorylation of beta-catenin by AKT promotes beta-catenin transcriptional activity. J Biol Chem 2007; 282:11221-9. [PMID: 17287208 PMCID: PMC1850976 DOI: 10.1074/jbc.m611871200] [Citation(s) in RCA: 679] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Increased transcriptional activity of beta-catenin resulting from Wnt/Wingless-dependent or -independent signaling has been detected in many types of human cancer, but the underlying mechanism of Wnt-independent regulation is poorly understood. We have demonstrated that AKT, which is activated downstream from epidermal growth factor receptor signaling, phosphorylates beta-catenin at Ser552 in vitro and in vivo. AKT-mediated phosphorylation of beta-catenin causes its disassociation from cell-cell contacts and accumulation in both the cytosol and the nucleus and enhances its interaction with 14-3-3zeta via a binding motif containing Ser552. Phosphorylation of beta-catenin by AKT increases its transcriptional activity and promotes tumor cell invasion, indicating that AKT-dependent regulation of beta-catenin plays a critical role in tumor invasion and development.
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Affiliation(s)
- Dexing Fang
- Brain Tumor Center and Department of Neuro-Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - David Hawke
- Department of Molecular Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Yanhua Zheng
- Brain Tumor Center and Department of Neuro-Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Yan Xia
- Brain Tumor Center and Department of Neuro-Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Jill Meisenhelder
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037
| | - Heinz Nika
- Department of Molecular Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Gordon B. Mills
- Department of Systems Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Ryuji Kobayashi
- Department of Molecular Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Tony Hunter
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037
| | - Zhimin Lu
- Brain Tumor Center and Department of Neuro-Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
- Department of Molecular Genetics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030
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703
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Dissanayake SK, Wade M, Johnson CE, O’Connell MP, Leotlela PD, French AD, Shah KV, Hewitt KJ, Rosenthal DT, Indig FE, Jiang Y, Nickoloff BJ, Taub DD, Trent JM, Moon RT, Bittner M, Weeraratna AT. The Wnt5A/protein kinase C pathway mediates motility in melanoma cells via the inhibition of metastasis suppressors and initiation of an epithelial to mesenchymal transition. J Biol Chem 2007; 282:17259-71. [PMID: 17426020 PMCID: PMC2263117 DOI: 10.1074/jbc.m700075200] [Citation(s) in RCA: 275] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We have shown that Wnt5A increases the motility of melanoma cells. To explore cellular pathways involving Wnt5A, we compared gain-of-function (WNT5A stable transfectants) versus loss-of-function (siRNA knockdown) of WNT5A by microarray analysis. Increasing WNT5A suppressed the expression of several genes, which were re-expressed after small interference RNA-mediated knockdown of WNT5A. Genes affected by WNT5A include KISS-1, a metastasis suppressor, and CD44, involved in tumor cell homing during metastasis. This could be validated at the protein level using both small interference RNA and recombinant Wnt5A (rWnt5A). Among the genes up-regulated by WNT5A was the gene vimentin, associated with an epithelial to mesenchymal transition (EMT), which involves decreases in E-cadherin, due to up-regulation of the transcriptional repressor, Snail. rWnt5A treatment increases Snail and vimentin expression, and decreases E-cadherin, even in the presence of dominant-negativeTCF4, suggesting that this activation is independent of Wnt/beta-catenin signaling. Because Wnt5A can signal via protein kinase C (PKC), the role of PKC in Wnt5A-mediated motility and EMT was also assessed using PKC inhibition and activation studies. Treating cells expressing low levels of Wnt5A with phorbol ester increased Snail expression inhibiting PKC in cells expressing high levels of Wnt5A decreased Snail. Furthermore, inhibition of PKC before Wnt5A treatment blocked Snail expression, implying that Wnt5A can potentiate melanoma metastasis via the induction of EMT in a PKC-dependent manner.
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Affiliation(s)
- Samudra K. Dissanayake
- Laboratory of Immunology, Gerontology Research Center, NIA, National Institutes of Health (NIH), Baltimore, Maryland 21224
| | - Michael Wade
- Laboratory of Immunology, Gerontology Research Center, NIA, National Institutes of Health (NIH), Baltimore, Maryland 21224
| | | | - Michael P. O’Connell
- Laboratory of Immunology, Gerontology Research Center, NIA, National Institutes of Health (NIH), Baltimore, Maryland 21224
| | - Poloko D. Leotlela
- Laboratory of Immunology, Gerontology Research Center, NIA, National Institutes of Health (NIH), Baltimore, Maryland 21224
| | - Amanda D. French
- Laboratory of Immunology, Gerontology Research Center, NIA, National Institutes of Health (NIH), Baltimore, Maryland 21224
| | - Kavita V. Shah
- Department of Pharmacology, Howard Hughes Medical Institute, and Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, Washington 98195
| | - Kyle J. Hewitt
- Laboratory of Immunology, Gerontology Research Center, NIA, National Institutes of Health (NIH), Baltimore, Maryland 21224
| | - Devin T. Rosenthal
- Laboratory of Immunology, Gerontology Research Center, NIA, National Institutes of Health (NIH), Baltimore, Maryland 21224
| | - Fred E. Indig
- Research Resources Branch, Gerontology Research Center, NIA, National Institutes of Health (NIH), Baltimore, Maryland 21224
| | - Yuan Jiang
- Cancer Genetics Branch, NHGRI, NIH, Bethesda, Maryland 20892
| | - Brian J. Nickoloff
- Department of Pathology, Loyola University Medical Center, Maywood, Illinois 60153
| | - Dennis D. Taub
- Laboratory of Immunology, Gerontology Research Center, NIA, National Institutes of Health (NIH), Baltimore, Maryland 21224
| | - Jeffrey M. Trent
- The Translational Genomics Research Institute, Phoenix, Arizona 85004
| | - Randall T. Moon
- Department of Pharmacology, Howard Hughes Medical Institute, and Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, Washington 98195
| | - Michael Bittner
- The Translational Genomics Research Institute, Phoenix, Arizona 85004
| | - Ashani T. Weeraratna
- Laboratory of Immunology, Gerontology Research Center, NIA, National Institutes of Health (NIH), Baltimore, Maryland 21224
- To whom correspondence should be addressed: Laboratory of Immunology, NIA, NIH, 5600 Nathan Shock Dr., Baltimore, MD 21224. Tel.: 410-558-8506; Fax: 410-558-8284; E-mail:
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704
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Tamburini J, Elie C, Bardet V, Chapuis N, Park S, Broët P, Cornillet-Lefebvre P, Lioure B, Ugo V, Blanchet O, Ifrah N, Witz F, Dreyfus F, Mayeux P, Lacombe C, Bouscary D. Constitutive phosphoinositide 3-kinase/Akt activation represents a favorable prognostic factor in de novo acute myelogenous leukemia patients. Blood 2007; 110:1025-8. [PMID: 17426258 DOI: 10.1182/blood-2006-12-061283] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The phosphoinositide 3-kinase (PI3K/Akt) pathway is activated in acute myelogenous leukemia (AML) and is promising for targeted inhibition. Ninety-two patients with primary AML were analyzed for PI3K/Akt constitutive activation. Fifty percent of the patients presented with constitutive PI3K activation (PI3K (+)). No difference was observed between PI3K (+) and PI3K (-) groups concerning age, sex, white blood cell count, lactate dehydrogenase (LDH) level, bone marrow blast cells, French-American-British (FAB) classification, cytogenetics, RAS or nucleophosmin (NPM) mutations. Slightly more FLT3-ITD was detected in the PI3K (-) group (P = .048). The complete remission rate was similar between the 2 groups. With a median follow-up of 26 months, we observed for PI3K (+) and PI3K (-) patients, respectively, 56% and 33% overall survival (P = .001) and 72% and 41% relapse-free survival (P = .001). Constitutive PI3K/Akt activity is a favorable prognosis factor in AML, even after adjustment for FLT3-ITD, and may confer a particular sensitivity to chemotherapy. A better understanding of the downstream effectors of the PI3K/Akt pathway is needed before targeting in AML.
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Affiliation(s)
- Jerome Tamburini
- Department d'Hematologie, Institut Cochin, 27 rue Faubourg Saint-Jacques, F-75014 Paris, France
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705
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Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K. An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. Am J Respir Crit Care Med 2007; 175:367-416. [PMID: 17277290 DOI: 10.1164/rccm.200604-571st] [Citation(s) in RCA: 3974] [Impact Index Per Article: 233.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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706
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Dillon RL, White DE, Muller WJ. The phosphatidyl inositol 3-kinase signaling network: implications for human breast cancer. Oncogene 2007; 26:1338-45. [PMID: 17322919 DOI: 10.1038/sj.onc.1210202] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The phosphatidyl inositol 3-kinase (PI3K)/Akt pathway is activated downstream of a variety of extracellular signals and activation of this signaling pathway impacts a number of cellular processes including cell growth, proliferation and survival. The alteration of components of this pathway, through either activation of oncogenes or inactivation of tumor suppressors, disrupts a signaling equilibrium and can thus lead to cellular transformation. The frequent dysregulation of the PI3K/Akt pathway in human cancer has made components of this pathway attractive for therapeutic targeting; however, a more comprehensive understanding of the signaling intricacies is necessary to develop pharmacological agents to target not only specific molecules, but also specific functions. Here, we review a series of experiments examining the contribution of molecules of this signaling network including PI3K, phosphatase and tensin homolog deleted on chromosome 10, integrin-linked kinase and Akt and address the significance to human breast cancer.
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Affiliation(s)
- R L Dillon
- Molecular Oncology Group and Departments of Biochemistry and Medicine, McGill University, Royal Victoria Hospital, 687 Pine Avenue West, Montreal, Quebec, Canada
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707
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Fitsialos G, Chassot AA, Turchi L, Dayem MA, LeBrigand K, Moreilhon C, Meneguzzi G, Buscà R, Mari B, Barbry P, Ponzio G. Transcriptional signature of epidermal keratinocytes subjected to in vitro scratch wounding reveals selective roles for ERK1/2, p38, and phosphatidylinositol 3-kinase signaling pathways. J Biol Chem 2007; 282:15090-102. [PMID: 17363378 DOI: 10.1074/jbc.m606094200] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Covering denuded dermal surfaces after injury requires migration, proliferation, and differentiation of skin keratinocytes. To clarify the major traits controlling these intermingled biological events, we surveyed the genomic modifications occurring during the course of a scratch wound closure of cultured human keratinocytes. Using a DNA microarray approach, we report the identification of 161 new markers of epidermal repair. Expression data, combined with functional analysis performed with specific inhibitors of ERK, p38(MAPK) and phosphatidylinositol 3-kinase (PI3K), demonstrate that kinase pathways exert very selective functions by precisely controlling the expression of specific genes. Inhibition of the ERK pathway totally blocks the wound closure and inactivates many early transcription factors and EGF-type growth factors. p38(MAPK) inhibition only delays "healing," probably in line with the control of genes involved in the propagation of injury-initiated signaling. In contrast, PI3K inhibition accelerates the scratch closure and potentiates the scratch-dependent stimulation of three genes related to epithelial cell transformation, namely HAS3, HBEGF, and ETS1. Our results define in vitro human keratinocyte wound closure as a repair process resulting from a fine balance between positive signals controlled by ERK and p38(MAPK) and negative ones triggered by PI3K. The perturbation of any of these pathways might lead to dysfunction in the healing process, similar to those observed in pathological wounding phenotypes, such as hypertrophic scars or keloids.
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708
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Noguchi M, Ropars V, Roumestand C, Suizu F. Proto‐oncogene TCL1: more than just a coactivator for Akt. FASEB J 2007; 21:2273-84. [PMID: 17360849 DOI: 10.1096/fj.06-7684com] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Serine threonine kinase Akt, also called PKB (protein kinase B), plays a central role in regulating intracellular survival. Deregulation of this Akt signaling pathway underlies various human neoplastic diseases. Recently, the proto-oncogene TCL1 (T cell leukemia 1), with a previously unknown physiological function, was shown to interact with the Akt pleckstrin homology domain, enhancing Akt kinase activity; hence, it functions as an Akt kinase coactivator. In contrast to pathological conditions in which the TCL1 gene is highly activated in various human neoplasmic diseases, the physiological expression of TCL1 is tightly limited to early developmental cells as well as various developmental stages of immune cells. The NBRE (nerve growth factor-responsive element) of the proximal TCL1 promoter sequences can regulate the restricted physiological expression of TCL1 in a negative feedback mechanism. Further, based on the NMR structural studies of Akt-TCL1 protein complexes, an inhibitory peptide, "Akt-in," consisting of the betaA strand of TCL1, has been identified and has therapeutic potential. This review article summarizes and discusses recent advances in the understanding of TCL1-Akt functional interaction in order to clarify the biological action of the proto-oncogene TCL1 family and the development avenues for a suppressive drug specific for Akt, a core intracellular survival regulator.
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Affiliation(s)
- Masayuki Noguchi
- Division of Cancer Biology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan.
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709
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Abstract
Nickel is a widely distributed metal that is industrially applied in many forms. Accumulated epidemiological evidence confirms that exposures to nickel compounds are associated with increased nasal and lung cancer incidence, both in mostly occupational exposures. Although the molecular mechanisms by which nickel compounds cause cancer are still under intense investigation, the carcinogenic actions of nickel compounds are thought to involve oxidative stress, genomic DNA damage, epigenetic effects, and the regulation of gene expression by activation of certain transcription factors related to corresponding signal transduction pathways. The present review summarizes our current knowledge on the molecular mechanisms of nickel carcinogenesis, with special emphasis on the role of nickel induced reactive oxygen species (ROS) and signal transduction pathways.
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Affiliation(s)
- Haitian Lu
- Nelson Institute of Environmental Medicine, School of Medicine, New York University, Tuxedo, New York 10987, USA
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710
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Brognard J, Sierecki E, Gao T, Newton AC. PHLPP and a Second Isoform, PHLPP2, Differentially Attenuate the Amplitude of Akt Signaling by Regulating Distinct Akt Isoforms. Mol Cell 2007; 25:917-31. [PMID: 17386267 DOI: 10.1016/j.molcel.2007.02.017] [Citation(s) in RCA: 458] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Revised: 08/30/2006] [Accepted: 02/20/2007] [Indexed: 11/24/2022]
Abstract
Akt/protein kinase B controls cell growth, proliferation, and survival. We recently discovered a novel phosphatase PHLPP, for PH domain leucine-rich repeat protein phosphatase, which terminates Akt signaling by directly dephosphorylating and inactivating Akt. Here we describe a second family member, PHLPP2, which also inactivates Akt, inhibits cell-cycle progression, and promotes apoptosis. These phosphatases control the amplitude of Akt signaling: depletion of either isoform increases the magnitude of agonist-evoked Akt phosphorylation by almost two orders of magnitude. Although PHLPP1 and PHLPP2 both dephosphorylate the same residue (hydrophobic phosphorylation motif) on Akt, they differentially terminate Akt signaling by regulating distinct Akt isoforms. Knockdown studies reveal that PHLPP1 specifically modulates the phosphorylation of HDM2 and GSK-3alpha through Akt2, whereas PHLPP2 specifically modulates the phosphorylation of p27 through Akt3. Our data unveil a mechanism to selectively terminate Akt-signaling pathways through the differential inactivation of specific Akt isoforms by specific PHLPP isoforms.
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Affiliation(s)
- John Brognard
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
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711
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Larson SD, Jackson LN, Riall TS, Uchida T, Thomas RP, Qiu S, Evers BM. Increased incidence of well-differentiated thyroid cancer associated with Hashimoto thyroiditis and the role of the PI3k/Akt pathway. J Am Coll Surg 2007; 204:764-73; discussion 773-5. [PMID: 17481480 PMCID: PMC2430882 DOI: 10.1016/j.jamcollsurg.2006.12.037] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2006] [Accepted: 12/14/2006] [Indexed: 12/21/2022]
Abstract
BACKGROUND The link between inflammation and cancer is well-established, but the link between Hashimoto thyroiditis (HT) and thyroid cancer remains controversial. The purpose of our study was to determine the incidence of patients with thyroid cancer and associated HT at our institution, to correlate our patient population demographics with the Surveillance, Epidemiology and End Results (SEER) database, and to assess the expression of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in patients with HT. STUDY DESIGN Demographic and histologic data were collected from patients undergoing thyroid resection at the University of Texas Medical Branch from 1987 to 2002 and compared with the SEER database. Immunohistochemistry for phosphorylated Akt (a marker of PI3K activity), Akt isoforms and PTEN (an inhibitor of PI3K) was performed on paraffin-embedded blocks of resected thyroid tissue. RESULTS Our patient population demographics and thyroid cancer incidence by histologic type were similar to patients in the SEER database. Ninety-eight (37.7%) resected specimens had pathologic changes consistent with HT; 43 (43.8%) had an associated well-differentiated thyroid cancer. Increased phosphorylated Akt, Akt1, and Akt2 expression was noted in regions of HT and thyroid cancer compared with regions of normal surrounding thyroid tissue. CONCLUSIONS Patients with HT were three times more likely to have thyroid cancer, suggesting a strong link between chronic inflammation and cancer development. PI3K/Akt expression was increased in both HT and well-differentiated thyroid cancer, suggesting a possible molecular mechanism for thyroid carcinogenesis.
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Affiliation(s)
- Shawn D Larson
- Department of Surgery, The University of Texas Medical Branch, Galveston, TX 77555-0536, USA
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712
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Maroulakou IG, Oemler W, Naber SP, Tsichlis PN. Akt1 ablation inhibits, whereas Akt2 ablation accelerates, the development of mammary adenocarcinomas in mouse mammary tumor virus (MMTV)-ErbB2/neu and MMTV-polyoma middle T transgenic mice. Cancer Res 2007; 67:167-77. [PMID: 17210696 DOI: 10.1158/0008-5472.can-06-3782] [Citation(s) in RCA: 197] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ample evidence to date links the phosphatidylinositol 3-kinase-regulated protein kinase Akt with the induction and progression of human cancer, including breast cancer. However, there are three Akt isoforms with limited information about their specificity during oncogenesis. This study addresses the role of the three isoforms in polyoma middle T (PyMT) and ErbB2/Neu-driven mammary adenocarcinomas in mice. The effects of ablation of Akt1, Akt2, and Akt3 on the induction and the biology of these tumors were dramatically different, with ablation of Akt1 inhibiting, ablation of Akt2 accelerating, and ablation of Akt3 having a small, not statistically significant, inhibitory effect on tumor induction by both transgenes. Whereas PyMT-induced tumors are all invasive, Akt1(-/-)Neu-induced tumors are more invasive than Akt2(-/-)Neu-induced tumors. Invasiveness, however, does not always correlate with metastasis. Ablation of individual Akt isoforms does not affect the development of the mammary gland during puberty or the expression of the transgenes. Akt ablation, therefore, influences tumor induction by modulating transgene-induced oncogenic signaling. Immunostaining for Ki-67 and cyclin D1 and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assays on tissue sections revealed that the delay of tumor induction in Akt1 knockout mice is due to the inhibitory effects of Akt1 ablation on cell proliferation and survival. Given that these animal models exhibit significant similarities to human breast cancer, the results of the present study may have significant translational implications because they may influence how Akt inhibitors will be used in the treatment of human cancer.
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MESH Headings
- Adenocarcinoma/enzymology
- Adenocarcinoma/genetics
- Adenocarcinoma/pathology
- Animals
- Apoptosis/physiology
- Cell Growth Processes/physiology
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Neoplastic
- Genes, erbB-2
- Mammary Glands, Animal/enzymology
- Mammary Neoplasms, Experimental/enzymology
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/pathology
- Mammary Tumor Virus, Mouse/genetics
- Mice
- Mice, Transgenic
- Proto-Oncogene Proteins c-akt/deficiency
- Proto-Oncogene Proteins c-akt/genetics
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Affiliation(s)
- Ioanna G Maroulakou
- Molecular Oncology Research Institute and Department of Pathology, Tufts-New England Medical Center, 750 Washington Street, Boston, MA 02111, USA.
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713
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Song L, Li J, Ye J, Yu G, Ding J, Zhang D, Ouyang W, Dong Z, Kim SO, Huang C. p85alpha acts as a novel signal transducer for mediation of cellular apoptotic response to UV radiation. Mol Cell Biol 2007; 27:2713-31. [PMID: 17242187 PMCID: PMC1899908 DOI: 10.1128/mcb.00657-06] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Apoptosis is an important cellular response to UV radiation (UVR), but the corresponding mechanisms remain largely unknown. Here we report that the p85alpha regulatory subunit of phosphatidylinositol 3-kinase (PI-3K) exerted a proapoptotic role in response to UVR through the induction of tumor necrosis factor alpha (TNF-alpha) gene expression. This special effect of p85alpha was unrelated to the PI-3K-dependent signaling pathway. Further evidence demonstrated that the inducible transcription factor NFAT3 was the major downstream target of p85alpha for the mediation of UVR-induced apoptosis and TNF-alpha gene transcription. p85alpha regulated UVR-induced NFAT3 activation by modulation of its nuclear translocation and DNA binding and the relevant transcriptional activities. Gel shift assays and site-directed mutagenesis allowed the identification of two regions in the TNF-alpha gene promoter that served as the NFAT3 recognition sequences. Chromatin immunoprecipitation assays further confirmed that the recruitment of NFAT3 to the endogenous TNF-alpha promoter was regulated by p85alpha upon UVR exposure. Finally, the knockdown of the NFAT3 level by its specific small interfering RNA decreased UVR-induced TNF-alpha gene transcription and cell apoptosis. The knockdown of endogenous p85alpha blocked NFAT activity and TNF-alpha gene transcription, as well as cell apoptosis. Thus, we demonstrated p85alpha-associated but PI-3K-independent cell death in response to UVR and identified a novel p85alpha/NFAT3/TNF-alpha signaling pathway for the mediation of cellular apoptotic responses under certain stress conditions such as UVR.
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Affiliation(s)
- Lun Song
- Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987, USA
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714
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Abstract
The phosphatidylinositol 3-kinase-Akt pathway plays a central role in growth, development, and metabolism in both normal and neoplastic cells. In skeletal muscle, Akt has been implicated in regulating regeneration and hypertrophy and in counteracting atrophy. Here we provide evidence that Akt1 and not Akt2 is essential for muscle differentiation. Using a robust model of MyoD-mediated muscle development, in which dominant-negative Akt blocked differentiation, we show that targeted loss of Akt1 was equally inhibitory. Selective elimination of Akt1 had no effect on myoblast viability or proliferation but prevented differentiation by impairing the transcriptional actions of MyoD. In contrast, knockdown of Akt2 had no effect on myoblast survival or differentiation and minimally inhibited MyoD-regulated transcription. Our results define isoform-specific Akt-regulated signaling pathways in muscle cells that act through Akt1 to sustain muscle gene activation and promote differentiation.
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Affiliation(s)
- Elizabeth M Wilson
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239, USA
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715
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Garg R, Juncadella IJ, Ramamoorthi N, Ashish, Ananthanarayanan SK, Thomas V, Rincón M, Krueger JK, Fikrig E, Yengo CM, Anguita J. Cutting edge: CD4 is the receptor for the tick saliva immunosuppressor, Salp15. THE JOURNAL OF IMMUNOLOGY 2007; 177:6579-83. [PMID: 17082567 DOI: 10.4049/jimmunol.177.10.6579] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Salp15 is an Ixodes scapularis salivary protein that inhibits CD4+ T cell activation through the repression of TCR ligation-triggered calcium fluxes and IL-2 production. We show in this study that Salp15 binds specifically to the CD4 coreceptor on mammalian host T cells. Salp15 specifically associates through its C-terminal residues with the outermost two extracellular domains of CD4. Upon binding to CD4, Salp15 inhibits the subsequent TCR ligation-induced T cell signaling at the earliest steps including tyrosine phosphorylation of the Src kinase Lck, downstream effector proteins, and lipid raft reorganization. These results provide a molecular basis to understanding the immunosuppressive activity of Salp15 and its specificity for CD4+ T cells.
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Affiliation(s)
- Renu Garg
- Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
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716
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Hollier M, Whistler T, Dawson C, Vernon SD. Two optimized combination assays to examine apoptosis pathways in clinical samples. Cytometry A 2007; 71:675-85. [PMID: 17623880 DOI: 10.1002/cyto.a.20422] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND A consequence of a number of diseases is an alteration in apoptosis. Currently, there is no single assay that measures the main stages of apoptosis, requiring that multiple assays be performed. This hinders studies on clinical samples that have limited cell numbers. Our objective was to combine and optimize assays that target specific stages of apoptosis for use in a typical clinical blood sample. METHODS Two flow cytometric assays were developed for use on peripheral blood mononuclear cells (PBMC) collected in two 8-ml tubes from a single draw. One measures caspase-12 activity, the level of active caspase-3 and DNA fragmentation. The second assesses depolarization of the mitochondria and phosphatidylserine externalization. Cell populations present within the samples were determined by flow cytometry. Apoptosis was validated by ELISA. RESULTS Each assay was optimized for use with cell numbers and sample volumes typical of clinical blood samples. Each combination assay effectively distinguished apoptotic from nonapoptotic blood cells. CONCLUSIONS This combined optimized method comprised of two independent assays makes it possible to assay the major pathways of apoptosis in addition to determining the blood cell subsets that are affected.
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Affiliation(s)
- Mark Hollier
- Chronic Viral Diseases Branch, Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30329, USA
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717
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Davies M, Hennessy B, Mills GB. Point mutations of protein kinases and individualised cancer therapy. Expert Opin Pharmacother 2007; 7:2243-61. [PMID: 17059381 DOI: 10.1517/14656566.7.16.2243] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The treatment of cancer is rapidly changing, with an increasing focus on converting our improved understanding of the molecular basis of disease into clinical benefit for patients. Protein kinases that are mutated in cancer represent attractive targets, as they may result in cellular dependency on the mutant kinase or its associated pathway for survival, a condition known as 'oncogene addiction'. Early clinical experiences have demonstrated dramatic clinical benefit of targeting oncogenic mutations in diseases that have been largely resistant to traditional cytotoxic chemotherapy. Further, mutational activation of kinases can indicate which patients are likely to respond to targeted therapeutics. However, these experiences have also illuminated a number of critical challenges that will have to be addressed in the development of effective drugs across different cancers, to fully realise the potential of individualised molecular therapy. This review utilises examples of genetic activation of kinases to illustrate many of the lessons learned, as well as those yet to be implemented.
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Affiliation(s)
- Michael Davies
- University of Texas--M D Anderson Cancer Center, Department of Medical Oncology, 1515 Holcombe Blvd, Unit 10, Houston, TX 77030, USA.
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718
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The Immune Reconstitution Inflammatory Syndrome (IRIS) in HIV infected patient – case report. HIV & AIDS REVIEW 2007. [DOI: 10.1016/s1730-1270(10)60076-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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719
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Acconcia F, Manavathi B, Mascarenhas J, Talukder AH, Mills G, Kumar R. An inherent role of integrin-linked kinase-estrogen receptor alpha interaction in cell migration. Cancer Res 2006; 66:11030-8. [PMID: 17108142 DOI: 10.1158/0008-5472.can-06-2676] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Integrin-linked kinase (ILK) and estrogen receptor (ER)-alpha modulate cell migration. However, the crosstalk between ERalpha and ILK and the role of ILK in ERalpha-mediated cell migration remain unexplored. Here, we report that ILK participates in ERalpha signaling in breast cancer cells. We found that ILK binds ERalpha in vitro and in vivo through a LXXLL motif in ILK. Estrogen prevented ERalpha-ILK binding, resulting in phosphatidylinositol 3-kinase (PI3K)-dependent increase in ILK kinase activity. Furthermore, the regulation of ERalpha-ILK interaction was dependent on the PI3K pathway. Unexpectedly, transient knockdown or inhibition of ILK caused hyperphosphorylation of ERalpha Ser(118) in an extracellular signal-regulated kinase/mitogen-activated protein kinase pathway-dependent manner and an enhanced ERalpha recruitment to the target chromatin and gene expression, a process reversed by overexpression of ILK. Compatible with these interactions, estrogen regulated cell migration via the PI3K/ILK/AKT pathway with stable ILK overexpression hyperactivating cell migration. Thus, status of ILK signaling may be an important modifier of ER signaling in breast cancer cells and this pathway could be exploited for therapeutic intervention in breast cancer cells.
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Affiliation(s)
- Filippo Acconcia
- Departments of Molecular and Cellular Oncology and Molecular Therapeutics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
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720
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Li J, Song L, Zhang D, Wei L, Huang C. Knockdown of NFAT3 blocked TPA-induced COX-2 and iNOS expression, and enhanced cell transformation in Cl41 cells. J Cell Biochem 2006; 99:1010-20. [PMID: 16475165 DOI: 10.1002/jcb.20834] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The nuclear factor of activated-T-cells (NFAT) family is a ubiquitous transcription factor that mediates regulation on various gene expressions. Recent studies indicate that NFAT may implicate in cancer process, mainly through its direct regulation on the cyclooxygenase-2 (COX-2) gene expression. There is also evidence suggesting another aspect of NFAT in tumor suppression. However, the according mechanism remains unknown. In this study, we used a small interfering RNA (siRNA) expression construct to study the role of NFAT3 in the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cell transformation with the tumor promotion-sensitive mouse epidermal Cl41 cells. Our results showed that TPA was able to induce NFAT3 activation in Cl41 cells. Stable transfection of NFAT3 siRNA specifically reduced endogenous NFAT3 expression. At the same time, TPA-induced expression of both COX-2 and inducible nitric oxide synthase (iNOS) were blocked. However, anchorage-independent transformation in response to TPA was significantly enhanced in NFAT3 siRNA stable transfectants as compared with vector transfectants. Moreover, treatment with the iNOS specific inhibitor aminoguanidine (AG) also enhanced Cl41 cells transformation induced by TPA. As COX-2 expression is proved to be required for cell transformation in Cl41 cells in our recent studies, our results demonstrate that the inducible NFAT3-mediated iNOS upregulation represents a novel potent tumor-suppressing pathway and may contribute to the tumor suppressor functions of NFAT protein.
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Affiliation(s)
- Jingxia Li
- Nelson Institute of Environmental Medicine, New York University School of Medicine, Tuxedo, New York 10987, USA
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721
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O'Connor RS, Mills ST, Jones KA, Ho SN, Pavlath GK. A combinatorial role for NFAT5 in both myoblast migration and differentiation during skeletal muscle myogenesis. J Cell Sci 2006; 120:149-59. [PMID: 17164296 DOI: 10.1242/jcs.03307] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Skeletal muscle regeneration depends on myoblast migration, differentiation and myofiber formation. Isoforms of the nuclear factor of activated T cells (NFAT) family of transcription factors display nonredundant roles in skeletal muscle. NFAT5, a new isoform of NFAT, displays many differences from NFATc1-c4. Here, we examine the role of NFAT5 in myogenesis. NFAT5+/- mice displayed a defect in muscle regeneration with fewer myofibers formed at early times after injury. NFAT5 has a muscle-intrinsic function because inhibition of NFAT5 transcriptional activity caused both a migratory and differentiation defect in cultured myoblasts. We identified Cyr61 as a target of NFAT5 signaling in skeletal muscle cells. Addition of Cyr61 to cells expressing inhibitory forms of NFAT5 rescued the migratory phenotype. These results demonstrate a role for NFAT5 in skeletal muscle cell migration and differentiation. Furthermore, as cell-cell interactions are crucial for myoblast differentiation, these data suggest that myoblast migration and differentiation are coupled and that NFAT5 is a key regulator.
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Affiliation(s)
- Roddy S O'Connor
- Graduate Program in Molecular and Systems Pharmacology, Emory University, Atlanta, GA 30322, USA
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722
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Wu C, Huang J. Phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin pathway is essential for neuroendocrine differentiation of prostate cancer. J Biol Chem 2006; 282:3571-83. [PMID: 17148458 DOI: 10.1074/jbc.m608487200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hormonal therapy of prostate cancer, by inhibiting androgen production and/or androgen function, is the treatment of choice for advanced prostate cancer. Although most patients respond initially, the effect is only temporary, and the tumor cells will resume proliferation in an androgen-deprived environment. The mechanism for androgen-independent proliferation of cancer cells is unclear. Hormonal therapy induces neuroendocrine differentiation of prostate cancer cells, which is hypothesized to contribute to tumor recurrence by a paracrine mechanism. We studied signal transduction pathways of neuroendocrine differentiation in LNCaP cells after androgen withdrawal, and we showed that both the phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin pathway and ERK are activated, but only the former is required for neuroendocrine differentiation. A constitutively active AKT promotes neuroendocrine differentiation and a dominant negative AKT inhibits it. Activation of AKT by IGF-1 leads to neuroendocrine differentiation, and neuroendocrine differentiation induced by epinephrine requires AKT activation. We also show that the AKT pathway is likely responsible for neuroendocrine differentiation in DU145, an androgen-independent prostate cancer cell line. Therefore, our study demonstrated a novel function of the AKT pathway in prostate cancer progression and identified potential targets that may be explored for the treatment of androgen-independent cancer.
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Affiliation(s)
- Chengyu Wu
- Department of Pathology, University of Rochester Medical Center, Rochester, New York 14642, USA
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723
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Ranjbar S, Tsytsykova AV, Lee SK, Rajsbaum R, Falvo JV, Lieberman J, Shankar P, Goldfeld AE. NFAT5 regulates HIV-1 in primary monocytes via a highly conserved long terminal repeat site. PLoS Pathog 2006; 2:e130. [PMID: 17173480 PMCID: PMC1698943 DOI: 10.1371/journal.ppat.0020130] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Accepted: 10/27/2006] [Indexed: 11/18/2022] Open
Abstract
To replicate, HIV-1 capitalizes on endogenous cellular activation pathways resulting in recruitment of key host transcription factors to its viral enhancer. RNA interference has been a powerful tool for blocking key checkpoints in HIV-1 entry into cells. Here we apply RNA interference to HIV-1 transcription in primary macrophages, a major reservoir of the virus, and specifically target the transcription factor NFAT5 (nuclear factor of activated T cells 5), which is the most evolutionarily divergent NFAT protein. By molecularly cloning and sequencing isolates from multiple viral subtypes, and performing DNase I footprinting, electrophoretic mobility shift, and promoter mutagenesis transfection assays, we demonstrate that NFAT5 functionally interacts with a specific enhancer binding site conserved in HIV-1, HIV-2, and multiple simian immunodeficiency viruses. Using small interfering RNA to ablate expression of endogenous NFAT5 protein, we show that the replication of three major HIV-1 viral subtypes (B, C, and E) is dependent upon NFAT5 in human primary differentiated macrophages. Our results define a novel host factor-viral enhancer interaction that reveals a new regulatory role for NFAT5 and defines a functional DNA motif conserved across HIV-1 subtypes and representative simian immunodeficiency viruses. Inhibition of the NFAT5-LTR interaction may thus present a novel therapeutic target to suppress HIV-1 replication and progression of AIDS.
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Affiliation(s)
- Shahin Ranjbar
- CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alla V Tsytsykova
- CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sang-Kyung Lee
- CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Bioengineering, Hanyang University, Seoul, Korea
| | - Ricardo Rajsbaum
- CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts, United States of America
| | - James V Falvo
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Judy Lieberman
- CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Premlata Shankar
- CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Anne E Goldfeld
- CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
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724
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Lu H, Li J, Zhang D, Stoner GD, Huang C. Molecular mechanisms involved in chemoprevention of black raspberry extracts: from transcription factors to their target genes. Nutr Cancer 2006; 54:69-78. [PMID: 16800774 DOI: 10.1207/s15327914nc5401_8] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Berries have attracted attention for their chemopreventive activities in last a few years. Dietary freeze-dried blackberries have been shown to reduce esophagus and colon cancer development induced by chemical carcinogen in rodents. To elucidate molecular mechanisms involved in chemoprevention by berry extracts, we employed mouse epidermal Cl 41 cell line, a well-characterized in vitro model in tumor promotion studies. Pretreatment of Cl 41 cells with methanol-extracted blackberry fraction RO-ME resulted in a dramatical inhibition of B(a)PDE-induced activation of AP-1 and NFkB, and expression of VEGF and COX-2. The inhibitory effects of RO-ME on B(a)PDE-induced activation of AP-1 and NFkappaB appear to be mediated via inhibition of MAPKs and IkappaBalpha phosphorylation, respectively. In view of the important roles of AP-1, NFkappaB, VEGF and COX-2 in tumor promotion/progression, and VEGF and COX-2 are target of AP-1 and NFkappaB, we anticipate that the ability of black raspberries to inhibit tumor development may be mediated by impairing signal transduction pathways leading to activation of AP-1 and NFkappaB, subsequently resulting in down-regulation of VEGF and COX-2 expression. The RO-ME fraction appears to be the major fraction responsible for the inhibitory activity of black raspberries.
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Affiliation(s)
- Haitian Lu
- Nelson Institute of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987, USA
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725
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Zhu Q, Krakowski AR, Dunham EE, Wang L, Bandyopadhyay A, Berdeaux R, Martin GS, Sun L, Luo K. Dual role of SnoN in mammalian tumorigenesis. Mol Cell Biol 2006; 27:324-39. [PMID: 17074815 PMCID: PMC1800653 DOI: 10.1128/mcb.01394-06] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
SnoN is an important negative regulator of transforming growth factor beta signaling through its ability to interact with and repress the activity of Smad proteins. It was originally identified as an oncoprotein based on its ability to induce anchorage-independent growth in chicken embryo fibroblasts. However, the roles of SnoN in mammalian epithelial carcinogenesis have not been well defined. Here we show for the first time that SnoN plays an important but complex role in human cancer. SnoN expression is highly elevated in many human cancer cell lines, and this high level of SnoN promotes mitogenic transformation of breast and lung cancer cell lines in vitro and tumor growth in vivo, consistent with its proposed pro-oncogenic role. However, this high level of SnoN expression also inhibits epithelial-to-mesenchymal transdifferentiation. Breast and lung cancer cells expressing the shRNA for SnoN exhibited an increase in cell motility, actin stress fiber formation, metalloprotease activity, and extracellular matrix production as well as a reduction in adherens junction proteins. Supporting this observation, in an in vivo breast cancer metastasis model, reducing SnoN expression was found to moderately enhance metastasis of human breast cancer cells to bone and lung. Thus, SnoN plays both pro-tumorigenic and antitumorigenic roles at different stages of mammalian malignant progression. The growth-promoting activity of SnoN appears to require its ability to bind to and repress the Smad proteins, while the antitumorigenic activity can be mediated by both Smad-dependent and Smad-independent pathways and requires the activity of small GTPase RhoA. Our study has established the importance of SnoN in mammalian epithelial carcinogenesis and revealed a novel aspect of SnoN function in malignant progression.
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Affiliation(s)
- Qingwei Zhu
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, CA 94720-3204, USA
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726
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Smirne C, Carbone A, Pirisi M, Bellone G. Imatinib mesilate: new perspectives in the treatment of solid tumours. Expert Opin Ther Pat 2006. [DOI: 10.1517/13543776.16.10.1359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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727
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Fornaro M, Burch PM, Yang W, Zhang L, Hamilton CE, Kim JH, Neel BG, Bennett AM. SHP-2 activates signaling of the nuclear factor of activated T cells to promote skeletal muscle growth. ACTA ACUST UNITED AC 2006; 175:87-97. [PMID: 17015617 PMCID: PMC2064501 DOI: 10.1083/jcb.200602029] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The formation of multinucleated myofibers is essential for the growth of skeletal muscle. The nuclear factor of activated T cells (NFAT) promotes skeletal muscle growth. How NFAT responds to changes in extracellular cues to regulate skeletal muscle growth remains to be fully defined. In this study, we demonstrate that mice containing a skeletal muscle-specific deletion of the tyrosine phosphatase SHP-2 (muscle creatine kinase [MCK]-SHP-2 null) exhibited a reduction in both myofiber size and type I slow myofiber number. We found that interleukin-4, an NFAT-regulated cytokine known to stimulate myofiber growth, was reduced in its expression in skeletal muscles of MCK-SHP-2-null mice. When SHP-2 was deleted during the differentiation of primary myoblasts, NFAT transcriptional activity and myotube multinucleation were impaired. Finally, SHP-2 coupled myotube multinucleation to an integrin-dependent pathway and activated NFAT by stimulating c-Src. Thus, SHP-2 transduces extracellular matrix stimuli to intracellular signaling pathways to promote skeletal muscle growth.
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Affiliation(s)
- Mara Fornaro
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
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728
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Zhou GL, Tucker DF, Bae SS, Bhatheja K, Birnbaum MJ, Field J. Opposing roles for Akt1 and Akt2 in Rac/Pak signaling and cell migration. J Biol Chem 2006; 281:36443-53. [PMID: 17012749 DOI: 10.1074/jbc.m600788200] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The Akt/PKB isoforms have different roles in animals, with Akt2 primarily regulating metabolic signaling and Akt1 regulating growth and survival. Here we show distinct roles for Akt1 and Akt2 in mouse embryo fibroblast cell migration and regulation of the cytoskeleton. Akt1-deficient cells responded poorly to platelet-derived growth factor while Akt2-deficient cells had a dramatically enhanced response, resulting in a substantial increase in dorsal ruffling. Swapping domains between Akt1 and Akt2 demonstrated that the N-terminal region containing the pleckstrin homology domain and a linker region distinguishes the two isoforms, while the catalytic domains are interchangeable. Akt2 knock-out cells also migrated faster than wild-type cells, especially through extracellular matrix (ECM), while Akt1 knock-out cells migrated more slowly than wild-type cells. Consistently, Akt2 knock-out cells had elevated Pak1 and Rac activities, suggesting that Akt2 inhibits Rac and Pak1. Both Akt2 and Akt1 associated in complexes with Pak1, but only Akt2 inhibited Pak1 in kinase assays, suggesting an underlying molecular basis for the different cellular phenotypes. Together these data provide evidence for an unexpected functional link between Akt2 and Pak1 that opposes the actions of Akt1 on cell migration.
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Affiliation(s)
- Guo-Lei Zhou
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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729
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Abstract
Cell for cell, probably no human cancer is as aggressive as melanoma. It is among a handful of cancers whose dimensions are reported in millimeters. Tumor thickness approaching 4 mm presents a high risk of metastasis, and a diagnosis of metastatic melanoma carries with it an abysmal median survival of 6-9 mo. What features of this malignancy account for such aggressive behavior? Is it the migratory history of its cell of origin or the programmed adaptation of its differentiated progeny to environmental stress, particularly ultraviolet radiation? While the answers to these questions are far from complete, major strides have been made in our understanding of the cellular, molecular, and genetic underpinnings of melanoma. More importantly, these discoveries carry profound implications for the development of therapies focused directly at the molecular engines driving melanoma, suggesting that we may have reached the brink of an unprecedented opportunity to translate basic science into clinical advances. In this review, we attempt to summarize our current understanding of the genetics and biology of this disease, drawing from expanding genomic information and lessons from development and genetically engineered mouse models. In addition, we look forward toward how these new insights will impact on therapeutic options for metastatic melanoma in the near future.
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Affiliation(s)
- Lynda Chin
- Melanoma Program, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
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730
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Joshi N, Johnson LL, Wei WQ, Abnet CC, Dong ZW, Taylor PR, Limburg PJ, Dawsey SM, Hawk ET, Qiao YL, Kirsch IR. Gene expression differences in normal esophageal mucosa associated with regression and progression of mild and moderate squamous dysplasia in a high-risk Chinese population. Cancer Res 2006; 66:6851-60. [PMID: 16818663 DOI: 10.1158/0008-5472.can-06-0662] [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: 12/26/2022]
Abstract
A randomized, double-blinded, placebo-controlled 2 x 2 factorial chemoprevention trial was conducted in Linxian, China to assess the effects of selenomethionine and celecoxib on the natural history of esophageal squamous dysplasia. Results from this study indicated that asymptomatic adults with mild dysplasia were more likely to show an improvement when treated with selenomethionine compared with placebo (P = 0.02). Prompted by this finding, we examined the molecular profiles associated with regression and progression of dysplastic lesions in normal mucosa from 29 individuals, a subset of the Linxian cohort, using the Affymetrix U133A chip. Twenty differentially expressed genes were associated with regression and 129 were associated with progression when we compared the change in gene expression over time. Genes associated with immune response (n = 15), cell cycle (n = 15), metabolism (n = 15), calcium transport or calcium ion activity (n = 10), regulation of transcription (n = 9), signal transduction (n = 7), cytoskeleton and microtubules (n = 5), nucleotide processing and biosynthesis (n = 4), G-coupled signaling (n = 4), and apoptosis (n = 3) were present in the list of 149 genes. Using the Expression Analysis Systematic Explorer pathway analysis program, only the immune response pathway was significantly overrepresented among these 149 genes. Individuals whose lesions regressed seemed to have higher expression of genes associated with immune stimulation, such as antigen presentation, survival of T cells, and T-cell activation (HLA-DRA, HLA-DPA1, HLA-DBQ1, CD58, and FCER1A). In contrast, individuals whose lesions progressed had higher expression of genes involved in immune suppression and inflammation (CNR2, NFATC4, NFRKB, MBP, INHBB, CMKLR1, CRP, ORMS, SERPINA7, and SERPINA1). These data suggest that local and systemic immune responses may influence the natural history of esophageal squamous dysplasia.
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Affiliation(s)
- Nina Joshi
- Genetics Branch, Center for Cancer Research, National Cancer Institute/NIH, EPS, 6120 Executive Boulevard, Bethesda, MD 20892, USA
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731
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Stambolic V, Woodgett JR. Functional distinctions of protein kinase B/Akt isoforms defined by their influence on cell migration. Trends Cell Biol 2006; 16:461-6. [PMID: 16870447 DOI: 10.1016/j.tcb.2006.07.001] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 06/30/2006] [Accepted: 07/13/2006] [Indexed: 02/02/2023]
Abstract
The three mammalian members of the protein kinase B/Akt (PKB/Akt) family have been implicated in a plethora of cellular signaling processes with key functions in control of cellular metabolism, growth, proliferation and apoptosis. As a major target of phosphatidylinositol (PI) 3-kinase signaling, the PKB/Akt isoforms also have central roles in a variety of human cancers, with effects on tumor initiation, progression and metastasis. It has been shown that isoform-specific functions of PKB/Akt family members can contribute to tumorigenesis on multiple levels. A series of recent studies documents the isoform-specific functions of PKB/Akt family members in regulation of cellular motility and migration by influencing numerous cellular targets involved in organization of the actin cytoskeleton, cellular interaction with the extracellular matrix, expression of motility genes and establishment of cellular polarity. A thorough insight into the isoform-specific roles of PKB/Akt proteins is essential for a full understanding of the complex biological outcomes elicited by PI 3-kinase and PKB/Akt signaling.
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Affiliation(s)
- Vuk Stambolic
- Ontario Cancer Institute, University Health Network, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
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732
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Tsai TT, Danielson KG, Guttapalli A, Oguz E, Albert TJ, Shapiro IM, Risbud MV. TonEBP/OREBP Is a Regulator of Nucleus Pulposus Cell Function and Survival in the Intervertebral Disc. J Biol Chem 2006; 281:25416-24. [PMID: 16772300 DOI: 10.1074/jbc.m601969200] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The nucleus pulposus is an aggrecan-rich hydrated tissue that permits the intervertebral disc to resist compressive loads. Adaptation to loading is achieved through an elevation in disc osmolarity mediated by the numerous charged glycosoaminoglycan side chains of the aggrecan molecule. The goal of this investigation was to determine the functional role of the osmo-regulatory protein, TonEBP, in cells of the nucleus pulposus. We found that TonEBP and its downstream target genes were robustly expressed in the tissues of the disc. Above 330 mosmol/kg, cultured nucleus pulposus cells up-regulated target genes TauT, BGT-1, and SMIT; above 450 mosmol/kg, there was raised expression of HSP-70. In hypertonic media there was activation of TauT and heat shock protein-70 (HSP-70) reporter activity and increased binding of TonEBP to the TonE motif. When cells were transfected with the dominant-negative form of TonEBP (DN-TonEBP) there was suppression of TauT and HSP-70 reporter gene expression; pTonEBP enhanced reporter gene expression. Moreover, in hypertonic media, forced expression of DN-TonEBP induced apoptosis. We suppressed TonEBP using small interfering RNA technique and noted a decrease in TauT reporter activity in isotonic as well as hyperosmolar media. Finally, we report that the aggrecan promoter contains two conserved TonE motifs. To evaluate the importance of these motifs, we overexpressed DN-TonEBP and partially silenced TonEBP using small interfering RNA. Both approaches resulted in suppression of aggrecan promoter activity. It is concluded that TonEBP permits the disc cells to adapt to the hyperosmotic milieu while autoregulating the expression of molecules that generate the unique extracellular environment.
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Affiliation(s)
- Tsung-Ting Tsai
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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733
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Tong EHY, Guo JJ, Huang AL, Liu H, Hu CD, Chung SSM, Ko BCB. Regulation of nucleocytoplasmic trafficking of transcription factor OREBP/TonEBP/NFAT5. J Biol Chem 2006; 281:23870-9. [PMID: 16782704 DOI: 10.1074/jbc.m602556200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The osmotic response element-binding protein (OREBP), also known as tonicity enhancer-binding protein (TonEBP) or NFAT5, regulates the hypertonicity-induced expression of a battery of genes crucial for the adaptation of mammalian cells to extracellular hypertonic stress. The activity of OREBP/TonEBP is regulated at multiple levels, including nucleocytoplasmic trafficking. OREBP/TonEBP protein can be detected in both the cytoplasm and nucleus under isotonic conditions, although it accumulates exclusively in the nucleus or cytoplasm when subjected to hypertonic or hypotonic challenges, respectively. Using immunocytochemistry and green fluorescent protein fusions, the protein domains that determine its subcellular localization were identified and characterized. We found that OREBP/TonEBP nuclear import is regulated by a nuclear localization signal. However, under isotonic conditions, nuclear export of OREBP/TonEBP is mediated by a CRM1-dependent, leucine-rich canonical nuclear export sequence (NES) located in the N terminus. Disruption of NES by site-directed mutagenesis yielded a mutant OREBP/TonEBP protein that accumulated in the nucleus under isotonic conditions but remained a target for hypotonicity-induced nuclear export. More importantly, a putative auxiliary export domain distal to the NES was identified. Disruption of the auxiliary export domain alone is sufficient to abolish the nuclear export of OREBP/TonEBP induced by hypotonicity. By using bimolecular fluorescence complementation assay, we showed that CRM1 interacts with OREBP/TonEBP, but not with a mutant protein deficient in NES. Our findings provide insight into how nucleocytoplasmic trafficking of OREBP/TonEBP is regulated by changes in extracellular tonicity.
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Affiliation(s)
- Edith H Y Tong
- Department of Chemistry, University of Hong Kong, Hong Kong Special Administrative Region, China
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734
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Corral RS, Iñiguez MA, Duque J, López-Pérez R, Fresno M. Bombesin induces cyclooxygenase-2 expression through the activation of the nuclear factor of activated T cells and enhances cell migration in Caco-2 colon carcinoma cells. Oncogene 2006; 26:958-69. [PMID: 16909108 DOI: 10.1038/sj.onc.1209856] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cyclooxygenase-2 (Cox-2), the gastrin-release peptide (GRP) and its cognate receptor (GRP-R) are overexpressed in a significant percentage of colorectal carcinomas and are associated with cell growth, invasiveness and tumor progression. However, a molecular link between all of them in adenocarcinomas has not been established. Here, we show that bombesin (BBS), a GRP homolog, stimulates the expression of Cox-2 mRNA and protein in human colon adenocarcinoma Caco-2 cells, resulting in enhanced release of prostaglandin E(2). These effects were markedly inhibited by the specific BBS antagonist RC-3940-II. BBS promotes the activation of the nuclear factor of activated T cells (NFAT) through a Ca(2+)/calcineurin (Cn)-linked pathway. Upon BBS stimulation, the NFATc1 isoform translocates into the nucleus with a concomitant increase in NFATc1 binding to two specific recognition sites in the promoter region of the Cox-2 gene. Furthermore, inhibition of Cn activity by the immunosuppressive drug cyclosporin A impaired NFAT activation and diminished Cox-2 expression in BBS-stimulated cells. Interestingly, BBS pretreatment strongly enhances the invasive capacity of carcinoma cells, effect which was inhibited by a Cox-2-specific inhibitor. These findings provide the first evidence for the involvement of the Ca(2+)/Cn/NFAT pathway in BBS-mediated induction of genes involved in colon carcinoma invasiveness such as Cox-2.
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Affiliation(s)
- R S Corral
- Centro de Biología Molecular 'Severo Ochoa', Universidad Autónoma de Madrid-CSIC, Madrid, Spain
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735
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Aramburu J, Drews-Elger K, Estrada-Gelonch A, Minguillón J, Morancho B, Santiago V, López-Rodríguez C. Regulation of the hypertonic stress response and other cellular functions by the Rel-like transcription factor NFAT5. Biochem Pharmacol 2006; 72:1597-604. [PMID: 16904650 DOI: 10.1016/j.bcp.2006.07.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Revised: 06/29/2006] [Accepted: 07/08/2006] [Indexed: 11/28/2022]
Abstract
Stress, be it from environmental factors or intrinsic to the cell as result of growth and metabolism, can be harmful to cells. Mammalian cells have developed numerous mechanisms to respond to diverse forms of stress. These mechanisms combine signaling cascades and activation of gene expression programs to orchestrate an adaptive response that will allow the cell to survive and resume its normal functioning. In this review we will focus on the transcription factor NFAT5, a fundamental regulator of the response to osmotic stress in mammalian cells. Identified in 1999, NFAT5 is the latest addition to the Rel family, which comprises the NF-kappaB and NFATc proteins. Though in some of its structural and functional features NFAT5 is a hybrid between these two major groups of Rel proteins, it has unique characteristics that make it stand on its own as a third type of Rel transcription factor. Since its discovery, NFAT5 has been studied mostly in the context of the hypertonicity stress response. The advent of mouse models deficient in NFAT5 and other recent advances have confirmed a fundamental osmoprotective role for this factor in mammals, but also revealed features that suggest it may have a wider range of functions.
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Affiliation(s)
- José Aramburu
- Molecular Immunopathology Unit, Department of Experimental and Health Sciences (DCEXS), Universitat Pompeu Fabra, Carrer Dr. Aiguader 80, E-08003 Barcelona, Spain.
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736
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French MA. The immunopathogenesis of mycobacterial immune restoration disease. THE LANCET. INFECTIOUS DISEASES 2006; 6:461-2. [PMID: 16870523 DOI: 10.1016/s1473-3099(06)70530-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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737
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Dejmek J, Säfholm A, Kamp Nielsen C, Andersson T, Leandersson K. Wnt-5a/Ca2+-induced NFAT activity is counteracted by Wnt-5a/Yes-Cdc42-casein kinase 1alpha signaling in human mammary epithelial cells. Mol Cell Biol 2006; 26:6024-36. [PMID: 16880514 PMCID: PMC1592795 DOI: 10.1128/mcb.02354-05] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 01/05/2006] [Accepted: 05/17/2006] [Indexed: 02/06/2023] Open
Abstract
Wnt-5a has been shown to influence the metastatic behavior of human breast cancer cells, and the loss of Wnt-5a expression is associated with metastatic disease. We show here that NFAT1, a transcription factor connected with breast cancer metastasis, is activated by Wnt-5a through a Ca2+ signaling pathway in human breast epithelial cells. This activation was simultaneously counteracted by a Wnt-5a-induced Yes/Cdc42 signaling pathway. The observation that inhibition of the Wnt-5a/Yes/Cdc42 signal prolonged the duration of ionomycin-induced NFAT1 activation revealed the general importance of this pathway. The Wnt-5a-induced inhibition of NFAT1 did not require glycogen synthase kinase 3beta, JNK, or Pak1 activity or modulation of the cytoskeleton. Instead, we observed that Wnt-5a induced a complex formation of NFAT1/casein kinase 1alpha, even upon treatment with ionomycin, which was blocked upon inhibition of the Wnt-5a/Yes/Cdc42 signaling pathway. Our results explain why Wnt-5a/Ca2+-induced NFAT activity is hard to detect and suggest a novel mechanism by which Wnt-5a can suppress tumor-specific, agonist-induced NFAT activity and thus the metastatic behavior of breast cancer cells.
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Affiliation(s)
- Janna Dejmek
- Experimental Pathology, Department of Laboratory Medicine, Lund University, U-MAS, Entrance 78, SE-205 02 Malmö, Sweden
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738
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Savas S, Schmidt S, Jarjanazi H, Ozcelik H. Functional nsSNPs from carcinogenesis-related genes expressed in breast tissue: potential breast cancer risk alleles and their distribution across human populations. Hum Genomics 2006; 2:287-96. [PMID: 16595073 PMCID: PMC3500178 DOI: 10.1186/1479-7364-2-5-287] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although highly penetrant alleles of BRCA1 and BRCA2 have been shown to predispose to breast cancer, the majority of breast cancer cases are assumed to result from the presence of low-moderate penetrant alleles and environmental carcinogens. Non-synonymous single nucleotide polymorphisms (nsSNPs) are hypothesised to contribute to disease susceptibility and approximately 30 per cent of them are predicted to have a biological significance. In this study, we have applied a bioinformatics-based strategy to identify breast cancer-related nsSNPs from 981 carcinogenesis-related genes expressed in breast tissue. Our results revealed a total of 367 validated nsSNPs, 109 (29.7 per cent) of which are predicted to affect the protein function (functional nsSNPs), suggesting that these nsSNPs are likely to influence the development and homeostasis of breast tissue and hence contribute to breast cancer susceptibility. Sixty-seven of the functional nsSNPs presented as commonly occurring nsSNPs (minor allele frequencies ≥ 5 per cent), representing excellent candidates for breast cancer susceptibility. Additionally, a non-uniform distribution of the common functional nsSNPs among different human populations was observed: 15 nsSNPs were reported to be present in all populations analysed, whereas another set of 15 nsSNPs was specific to particular population(s). We propose that the nsSNPs analysed in this study constitute a unique resource of potential genetic factors for breast cancer susceptibility. Furthermore, the variations in functional nsSNP allele frequencies across major population backgrounds may point to the potential variability of the molecular basis of breast cancer predisposition and treatment response among different human populations.
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Affiliation(s)
- Sevtap Savas
- Fred A. Litwin Centre for Cancer Genetics, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON, M5G 1X5, Canada
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, 600 University Avenue, Toronto, ON, M5G IX5, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 100 College Street, Toronto, ON, M5G IL5, Canada
| | - Steffen Schmidt
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Hamdi Jarjanazi
- Fred A. Litwin Centre for Cancer Genetics, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON, M5G 1X5, Canada
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, 600 University Avenue, Toronto, ON, M5G IX5, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 100 College Street, Toronto, ON, M5G IL5, Canada
| | - Hilmi Ozcelik
- Fred A. Litwin Centre for Cancer Genetics, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON, M5G 1X5, Canada
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, 600 University Avenue, Toronto, ON, M5G IX5, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 100 College Street, Toronto, ON, M5G IL5, Canada
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739
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Cunningham SC, Gallmeier E, Hucl T, Dezentje DA, Calhoun ES, Falco G, Abdelmohsen K, Gorospe M, Kern SE. Targeted deletion of MKK4 in cancer cells: a detrimental phenotype manifests as decreased experimental metastasis and suggests a counterweight to the evolution of tumor-suppressor loss. Cancer Res 2006; 66:5560-4. [PMID: 16740690 DOI: 10.1158/0008-5472.can-06-0555] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tumor-suppressors have commanded attention due to the selection for their inactivating mutations in human tumors. However, relatively little is understood about the inverse, namely, that tumors do not select for a large proportion of seemingly favorable mutations in tumor-suppressor genes. This could be explained by a detrimental phenotype accruing in a cell type-specific manner to most cells experiencing a biallelic loss. For example, MKK4, a tumor suppressor gene distinguished by a remarkably consistent mutational rate across diverse tumor types and an unusually high rate of loss of heterozygosity, has the surprisingly low rate of genetic inactivation of only approximately 5%. To explore this incongruity, we engineered a somatic gene knockout of MKK4 in human cancer cells. Although the null cells resembled the wild-type cells regarding in vitro viability and proliferation in plastic dishes, there was a marked difference in a more relevant in vivo model of experimental metastasis and tumorigenesis. MKK4(-/-) clones injected i.v. produced fewer lung metastases than syngeneic MKK4-competent cells (P = 0.0034). These findings show how cell type-specific detrimental phenotypes can offer a paradoxical and yet key counterweight to the selective advantage attained by cells as they experiment with genetic null states during tumorigenesis, the resultant balance then determining the observed biallelic mutation rate for a given tumor-suppressor gene.
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Affiliation(s)
- Steven C Cunningham
- Department of Oncology, Sidney Kimmel Cancer Research Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
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740
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Lesho E. Evidence base for using corticosteroids to treat HIV-associated immune reconstitution syndrome. Expert Rev Anti Infect Ther 2006; 4:469-78. [PMID: 16771623 DOI: 10.1586/14787210.4.3.469] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Most of the evidence supporting the use of corticosteroids (steroids) for immune reconstitution syndrome (IRS) comes from case reports or retrospective series and is of low quality. However, when steroids are used, they have usually been associated with clinical improvement or resolution of IRS. Except in the case of hepatitis B- or C-associated IRS, there have been no reports of worsening of the IRS or adverse outcome due to steroid use. After ruling out other conditions which can mimic IRS, clinicians should strongly consider steroids when managing IRS associated with mycobacterial or fungal pathogens when there is severe disease, or when other measures have failed.
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Affiliation(s)
- Emil Lesho
- Walter Reed Army Medical Center, Infectious Diseases, 11120 Nicholas Drive, Silver Spring, MD 20902, USA.
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741
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Petersen CC, Petersen MS, Agger R, Hokland ME. Accumulation in tumor tissue of adoptively transferred T cells: A comparison between intravenous and intraperitoneal injection. J Immunother 2006; 29:241-9. [PMID: 16699367 DOI: 10.1097/01.cji.0000203078.97493.c3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Accumulation of T cells at the tumor is essential in cancer immunotherapy based on adoptive transfer of tumor-specific T cells. To gain further insight into the accumulation process and to evaluate the effect of using different routes of cell transfer, we investigated the accumulation of ovalbumin-specific CD8+ T cells (OT-I) injected either intravenously (IV) or intraperitoneally (IP) into mice carrying a subcutaneous tumor of the ovalbumin-expressing melanoma cell line B16-OVA. Maximal accumulation of the adoptively transferred cells in tumor tissue was observed 5 days after injection, irrespective of the injection route. The route of injection affected neither the total number of adoptively transferred cells found in tumor tissue nor the kinetics of this accumulation. In the spleen, however, the accumulation of adoptively transferred cells was clearly dependent on the injection route. IP injections resulted in a large number of adoptively transferred cells in the spleen on all days analyzed. In comparison, IV injection resulted in significantly fewer adoptively transferred cells in the spleen, and this number decreased over time. The route of injection affected neither the activation status of the adoptively transferred T cells that accumulated at the tumor site, nor the ability of these cells to control tumor growth. Two cell populations, SIINFEKL-tetramer(Low)(Tet(Low))CD69+ CD25+ and Tet(high)CD69- CD25-, were present in tumor samples, whereas only Tet(High)CD69- CD25- cells accumulated in the spleen. In tumors, IV injection resulted in a higher fraction of adoptively transferred cells with an activated phenotype (Tet(Low)CD69+ CD25+) compared with IP injection.
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Affiliation(s)
- Charlotte C Petersen
- Institute of Medical Microbiology and Immunology, Aarhus University, Aarhus 8000, Denmark.
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742
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Affiliation(s)
- Charles L Sawyers
- Department of Medicine, University of California, Los Angeles, Los Angeles, USA
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743
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Yan Y, Li J, Ouyang W, Ma Q, Hu Y, Zhang D, Ding J, Qu Q, Subbaramaiah K, Huang C. NFAT3 is specifically required for TNF-α-induced cyclooxygenase-2 (COX-2) expression and transformation of Cl41 cells. J Cell Sci 2006; 119:2985-94. [PMID: 16803872 DOI: 10.1242/jcs.03014] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
NFAT family is recognized as a transcription factor for inflammation regulation by inducing the expression of proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), the key mediator of inflammation, which was reported to induce cell transformation in mouse epidermal Cl41 cells. In this study, we demonstrated that TNF-α was able to induce NFAT activation, as well as the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). The induction of COX-2 by TNF-α was abolished by knockdown of NFAT3 with its siRNA, while the induction of iNOS was not effected. Moreover, TNF-α-induced anchorage-independent cell growth was significantly inhibited by NFAT3 siRNA and cyclosporine A, a chemical inhibitor for the calcineurin/NFAT pathway, which suggests the importance of NFAT3 in regulating TNF-α-induced anchorage-independent cell growth. Consequently, impairment of COX-2 by its siRNA or selective inhibitor also inhibited TNF-α-induced anchorage-independent cell growth. Taken together, our results indicate that NFAT3 plays an important role in the regulation of TNF-α-induced anchorage-independent cell growth, at least partially, by inducing COX-2 expression in Cl41 cells. These findings suggest that NFAT3/cyclooxygenase-2 act as a link between inflammation and carcinogenesis by being involved in the tumor promotion stage.
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Affiliation(s)
- Yan Yan
- Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987, USA
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744
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Abstract
The frequent deregulation of the phosphoinositide 3-kinase/Akt survival signaling pathway in cancer has prompted significant interest in blocking this pathway to treat cancer. Recently, however, two studies have shown that the Akt isoform Akt1 limits the invasive migration of breast cancer cells. These studies suggest that Akt1 may have a dual role in tumorigenesis, acting not only pro-oncogenically by suppressing apoptosis but also anti-oncogenically by suppressing invasion and metastasis. We discuss the possible implications of these findings for therapeutic development of Akt inhibitors to treat cancer.
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Affiliation(s)
- Alex Toker
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston 02215, USA.
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745
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Li J, Lu H, Huang C. NFAT3 is Required for EGF-Induced COX-2 Transcription, but Neither iNOS Transcription Nor Cell Transformation in Cl 41 Cells. Mol Cell Biochem 2006; 289:73-82. [PMID: 16718377 DOI: 10.1007/s11010-006-9149-z] [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: 12/04/2005] [Accepted: 02/03/2006] [Indexed: 10/24/2022]
Abstract
Epidermal growth factor (EGF) has been reported to act as a tumor promoter in several tissues, such as skin, in association with the induction of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). However, molecular mechanisms involved in these regulations are not well defined. This study addressed a potential role of nuclear factor of activated T cells 3 (NFAT3) in EGF-induced COX-2 and iNOS transcription and cell transformation in mouse epidermal Cl 41 cells. We found that EGF markedly induced anchorage-independent growth (cell transformation) of Cl 41 cells, as well as COX-2 (> 6-fold) and iNOS (> 5-fold) promoter-dependent transcription. The EGF-induced COX-2 transcription was blocked by knockdown of NFAT3 with NFAT3 siRNA, whereas the transcription of iNOS and cell transformation induced by EGF were not affected. Although our recent studies supported that NFAT3 plays an essential role in chemical carcinogen benzo[a]pyrene-7,8-diol-9,10-epoxide (B[a]PDE)-induced cell transformation, the data presented here demonstrated that NFAT3 is required for EGF-induced COX-2 transcription, but neither iNOS transcription nor cell transformation, indicating that the role of NFAT3 in regulating cell transformation is carcinogen-specific.
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Affiliation(s)
- Jingxia Li
- Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987, USA
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746
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Rieux-Laucat F, Hivroz C, Lim A, Mateo V, Pellier I, Selz F, Fischer A, Le Deist F. Inherited and somatic CD3zeta mutations in a patient with T-cell deficiency. N Engl J Med 2006; 354:1913-21. [PMID: 16672702 DOI: 10.1056/nejmoa053750] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A four-month-old boy with primary immunodeficiency was found to have a homozygous germ-line mutation of the gene encoding the CD3zeta subunit of the T-cell receptor-CD3 complex. CD3zeta is necessary for the development and function of T cells. Some of the patient's T cells had low levels of the T-cell receptor-CD3 complex and carried the Q70X mutation in both alleles of CD3zeta, whereas other T cells had normal levels of the complex and bore the Q70X mutation on only one allele of CD3zeta, plus one of three heterozygous somatic mutations of CD3zeta on the other allele, allowing expression of poorly functional T-cell receptor-CD3 complexes.
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747
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Dittmer A, Vetter M, Schunke D, Span PN, Sweep F, Thomssen C, Dittmer J. Parathyroid Hormone-related Protein Regulates Tumor-relevant Genes in Breast Cancer Cells. J Biol Chem 2006; 281:14563-72. [PMID: 16551631 DOI: 10.1074/jbc.m510527200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The effect of endogenous parathyroid hormone-related protein (PTHrP) on gene expression in breast cancer cells was studied. We suppressed PTHrP expression in MDA-MB-231 cells by RNA interference and analyzed changes in gene expression by microarray analysis. More than 200 genes showed altered expression in response to a PTHrP-specific small interfering (si) RNA (siPTHrP). Cell cycle-regulating gene CDC2 and genes (CDC25B and Tome-1) that control CDC2 activity showed increased expression in the presence of siPTHrP. CDC2 activity was also found to be higher in siPTHrP-treated cells. Studies with PTHrP peptides 1-34 and 67-86, forskolin, and a PTH1 receptor (PTH1R)-specific siRNA showed that PTHrP regulates CDC2 and CDC25B, at least in part, via PTH1R in a cAMP-independent manner. Other siPTHrP-responsive genes included integrin alpha6 (ITGA6), KISS-1, and PAI-1. When combined, siRNAs against ITGA6, PAI-1, and KISS-1 could mimic the negative effect of siPTHrP on migration, whereas siKISS-1 and siPTHrP similarly reduced the proliferative activity of the cells. Comparative expression analyses with 50 primary breast carcinomas revealed that the RNA level of ITGA6 correlates with that of PTHrP, and higher CDC2 and CDC25B values are found at low PTHrP expression. Our data suggest that PTHrP has a profound effect on gene expression in breast cancer cells and, as a consequence, contributes to the regulation of important cellular activities, such as migration and proliferation.
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Affiliation(s)
- Angela Dittmer
- Klinik für Gynäkologie, Universität Halle, Ernst-Grube-Strasse 40, 06120 Halle, Germany
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748
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Troadec S, Bès C, Chentouf M, Nguyen B, Briant L, Jacquet C, Chebli K, Pugnière M, Roquet F, Cerutti M, Chardès T. Biological activities on T lymphocytes of a baculovirus-expressed chimeric recombinant IgG1 antibody with specificity for the CDR3-like loop on the D1 domain of the CD4 molecule. Clin Immunol 2006; 119:38-50. [PMID: 16426893 DOI: 10.1016/j.clim.2005.11.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 11/14/2005] [Accepted: 11/22/2005] [Indexed: 12/16/2022]
Abstract
A baculovirus-expressed chimeric recombinant IgG1 (rIgG1) antibody, with Cgamma1 and Ckappa human constant domains, was derived from the murine monoclonal antibody (mAb) 13B8.2, which is specific for the CDR3-like loop of the CD4 molecule and which inhibits HIV-1 replication. Chimeric rIgG1 antibody 13B8.2 blocked, in a dose-dependent manner, antigen presentation through inhibition of subsequent IL-2 secretion by stimulated T cells. The one-way mixed lymphocyte reaction was abrogated by previous addition of baculovirus-produced rIgG1 13B8.2 in the T-cell culture. Anti-proliferative activity of rIgG1 was demonstrated on CD3-activated CD4+ T lymphocytes from healthy donors, such effect being associated with reduced IL-2 secretion of activated T cells. On the other hand, no proliferation inhibition was observed on CD4+ T lymphocytes activated with phorbol ester plus ionomycin, suggesting that rIgG1 13B8.2 preferentially acts on a proximal TCR-induced signaling pathway. Treatment of DBA1/J human CD4-transgenic mice with 100 microg of recombinant antibody for three consecutive days led to in vivo recovery of rIgG1 antibody 13B8.2 both coated on murine T lymphocytes and free in mouse serum, without CD4 depletion or down-modulation. These findings predict that the baculovirus-expressed chimeric rIgG1 anti-CD4 antibody 13B8.2 is a promising candidate for immunotherapy.
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Affiliation(s)
- Samuel Troadec
- CNRS UMR 5160, Centre de Pharmacologie et Biotechnologie pour la Santé, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 5, France
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749
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Liu H, Radisky DC, Nelson CM, Zhang H, Fata JE, Roth RA, Bissell MJ. Mechanism of Akt1 inhibition of breast cancer cell invasion reveals a protumorigenic role for TSC2. Proc Natl Acad Sci U S A 2006; 103:4134-9. [PMID: 16537497 PMCID: PMC1390746 DOI: 10.1073/pnas.0511342103] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Akt1 is frequently up-regulated in human tumors and has been shown to accelerate cell proliferation and to suppress programmed cell death; consequently, inhibition of the activity of Akt1 has been seen as an attractive target for therapeutic intervention. Paradoxically, hyperactivation of the Akt1 oncogene can also prevent the invasive behavior that underlies progression to metastasis. Here we show that overexpression of activated myr-Akt1 in human breast cancer cells phosphorylates and thereby targets the tumor suppressor tuberous sclerosis complex 2 (TSC2) for degradation, leading to reduced Rho-GTPase activity, decreased actin stress fibers and focal adhesions, and reduced motility and invasion. Overexpression of TSC2 rescues the migration phenotype of myr-Akt1-expressing tumor cells, and high levels of TSC2 in breast cancer patients correlate with increased metastasis and reduced survival. These data indicate that the functional properties of genes designated as oncogenes or tumor suppressor genes depend on the context of the cell type and the tissues studied, and suggest the need for caution in designing therapies targeting the function of individual genes in epithelial tissues.
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Affiliation(s)
- Hong Liu
- *Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
| | - Derek C. Radisky
- *Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
| | - Celeste M. Nelson
- *Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
| | - Hui Zhang
- *Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
| | - Jimmie E. Fata
- *Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
| | - Richard A. Roth
- Department of Molecular Pharmacology, Stanford University School of Medicine, Stanford, CA 94305
| | - Mina J. Bissell
- *Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
- To whom correspondence should be addressed. E-mail:
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750
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Yoon SO, Shin S, Lipscomb EA. A Novel Mechanism for Integrin-Mediated Ras Activation in Breast Carcinoma Cells: The α6β4 Integrin Regulates ErbB2 Translation and Transactivates Epidermal Growth Factor Receptor/ErbB2 Signaling. Cancer Res 2006; 66:2732-9. [PMID: 16510594 DOI: 10.1158/0008-5472.can-05-2941] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
ErbB2 (HER2, Neu) and Ras play key roles in tumor invasion and metastasis. We identified a novel mechanism by which integrin alpha(6)beta(4) regulates ErbB2 expression, Ras activation, and the invasion of breast carcinoma cells. Here we show that integrin alpha(6)beta(4) regulates Ras activity especially in serum-depleted condition. Down-regulation of beta(4) integrin by beta(4) short hairpin RNA (shRNA) decreased Ras activity and carcinoma invasion whereas reexpression of this integrin restored Ras activity. ErbB2, a binding partner of epidermal growth factor receptor (EGFR), and EGFR modulated Ras activity, and integrin alpha(6)beta(4) regulated phospho-EGFR level without affecting EGFR expression. We also found that integrin alpha(6)beta(4) is involved in ErbB2 expression. Depletion of beta(4) by shRNA reduced ErbB2 protein level without affecting ErbB2 mRNA level and reexpression of beta(4) increased ErbB2 protein level. Reduction of eukaryotic initiation factor 4E, a rate-limiting factor for cap-dependent translation, decreased ErbB2 protein level, and beta(4) shRNA cells exhibited a shift in ErbB2 mRNA to light polysomes compared with control cells. These results show that integrin alpha(6)beta(4) regulates ErbB2 through translational control. In summary, we propose a novel mechanism for ErbB2 up-regulation and Ras activation in serum-depleted breast cancer cells; integrin alpha(6)beta(4) regulates the expression of ErbB2 and the subsequent phosphorylation of EGFR and activation of Ras. These findings provide a mechanism that substantiates the reported role of alpha(6)beta(4) in carcinoma invasion.
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Affiliation(s)
- Sang-Oh Yoon
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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