1
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Noro T, Shah SH, Yin Y, Kawaguchi R, Yokota S, Chang KC, Madaan A, Sun C, Coppola G, Geschwind D, Benowitz LI, Goldberg JL. Elk-1 regulates retinal ganglion cell axon regeneration after injury. Sci Rep 2022; 12:17446. [PMID: 36261683 PMCID: PMC9581912 DOI: 10.1038/s41598-022-21767-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 09/30/2022] [Indexed: 01/12/2023] Open
Abstract
Adult central nervous system (CNS) axons fail to regenerate after injury, and master regulators of the regenerative program remain to be identified. We analyzed the transcriptomes of retinal ganglion cells (RGCs) at 1 and 5 days after optic nerve injury with and without a cocktail of strongly pro-regenerative factors to discover genes that regulate survival and regeneration. We used advanced bioinformatic analysis to identify the top transcriptional regulators of upstream genes and cross-referenced these with the regulators upstream of genes differentially expressed between embryonic RGCs that exhibit robust axon growth vs. postnatal RGCs where this potential has been lost. We established the transcriptional activator Elk-1 as the top regulator of RGC gene expression associated with axon outgrowth in both models. We demonstrate that Elk-1 is necessary and sufficient to promote RGC neuroprotection and regeneration in vivo, and is enhanced by manipulating specific phosphorylation sites. Finally, we co-manipulated Elk-1, PTEN, and REST, another transcription factor discovered in our analysis, and found Elk-1 to be downstream of PTEN and inhibited by REST in the survival and axon regenerative pathway in RGCs. These results uncover the basic mechanisms of regulation of survival and axon growth and reveal a novel, potent therapeutic strategy to promote neuroprotection and regeneration in the adult CNS.
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Affiliation(s)
- Takahiko Noro
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, 1651 Page Mill Rd, Palo Alto, CA, 94034, USA
- Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan
| | - Sahil H Shah
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, 1651 Page Mill Rd, Palo Alto, CA, 94034, USA.
- Medical Scientist Training Program, University of California San Diego, La Jolla, CA, USA.
| | - Yuqin Yin
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Riki Kawaguchi
- Departments of Neurology and Psychiatry, University of California Los Angeles, Los Angeles, CA, USA
| | - Satoshi Yokota
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, 1651 Page Mill Rd, Palo Alto, CA, 94034, USA
- Kobe City Eye Hospital, Kobe, Hyogo, Japan
| | - Kun-Che Chang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ankush Madaan
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, 1651 Page Mill Rd, Palo Alto, CA, 94034, USA
| | - Catalina Sun
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, 1651 Page Mill Rd, Palo Alto, CA, 94034, USA
| | - Giovanni Coppola
- Departments of Neurology and Psychiatry, University of California Los Angeles, Los Angeles, CA, USA
| | - Daniel Geschwind
- Departments of Neurology and Psychiatry, University of California Los Angeles, Los Angeles, CA, USA
| | - Larry I Benowitz
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, 1651 Page Mill Rd, Palo Alto, CA, 94034, USA
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2
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Urena F, Ma C, Hoffmann FW, Nunes LGA, Urschitz J, Moisyadi S, Khadka VS, Deng Y, Hoffmann PR. T-cell activation decreases miRNA-15a/16 levels to promote MEK1-ERK1/2-Elk1 signaling and proliferative capacity. J Biol Chem 2022; 298:101634. [PMID: 35085550 PMCID: PMC8861121 DOI: 10.1016/j.jbc.2022.101634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 01/13/2022] [Accepted: 01/18/2022] [Indexed: 02/08/2023] Open
Abstract
While miRs have been extensively studied in the context of malignancy and tumor progression, their functions in regulating T-cell activation are less clear. In initial studies, we found reduced levels of miR-15a/16 at 3 to 18 h post-T-cell receptor (TCR) stimulation, suggesting a role for decreased levels of this miR pair in shaping T-cell activation. To further explore this, we developed an inducible miR15a/16 transgenic mouse model to determine how elevating miR-15a/16 levels during early stages of activation would affect T-cell proliferation and to identify TCR signaling pathways regulated by this miR pair. Doxycycline (DOX)-induced expression of miR-15a/16 from 0 to 18 h post-TCR stimulation decreased ex vivo T-cell proliferation as well as in vivo antigen-specific T-cell proliferation. We also combined bioinformatics and proteomics approaches to identify the mitogen-activated protein kinase kinase 1 (MEK1) (Map2k1) as a target of miR-15a/16. MEK1 targeting by miR-15a/16 was confirmed using miR mimics that decreased Map2k1 mRNA containing the 3'-UTR target nucleotide sequence (UGCUGCUA) but did not decrease Map2k1 containing a mutated control sequence (AAAAAAAA). Phosphorylation of downstream signaling molecules, extracellular signal-regulated protein kinase 1/2 (ERK1/2) and Elk1, was also decreased by DOX-induced miR-15a/16 expression. In addition to MEK1, ERK1 was subsequently found to be targeted by miR-15a/16, with DOX-induced miR-15a/16 reducing total ERK1 levels in T cells. These findings show that TCR stimulation reduces miR-15a/16 levels at early stages of T-cell activation to facilitate increased MEK1 and ERK1, which promotes the sustained MEK1-ERK1/2-Elk1 signaling required for optimal proliferation.
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Affiliation(s)
- Frank Urena
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA; Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Chi Ma
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - FuKun W Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Lance G A Nunes
- Department of Anatomy, Physiology and Biochemistry, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Johann Urschitz
- Department of Anatomy, Physiology and Biochemistry, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Stefan Moisyadi
- Department of Anatomy, Physiology and Biochemistry, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Vedbar S Khadka
- Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Youping Deng
- Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Peter R Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA.
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3
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Zhang J, Zhang L, Shi H, Feng S, Feng T, Chen J, Zhang X, Han Y, Liu J, Wang Y, Ji Z, Jing Z, Liu D, Shi D, Feng L. Swine acute diarrhea syndrome coronavirus replication is reduced by inhibition of the extracellular signal-regulated kinase (ERK) signaling pathway. Virology 2022; 565:96-105. [PMID: 34768113 PMCID: PMC8556614 DOI: 10.1016/j.virol.2021.10.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 01/04/2023]
Abstract
Swine acute diarrhea syndrome coronavirus (SADS-CoV) is a newly discovered enteric coronavirus. We have previously shown that the caspase-dependent FASL-mediated and mitochondrion-mediated apoptotic pathways play a central role in SADS-CoV-induced apoptosis, which facilitates viral replication. However, the roles of intracellular signaling pathways in SADS-CoV-mediated cell apoptosis and the relative advantages that such pathways confer on the host or virus remain largely unknown. In this study, we show that SADS-CoV induces the activation of ERK during infection, irrespective of viral biosynthesis. The knockdown or chemical inhibition of ERK1/2 significantly suppressed viral protein expression and viral progeny production. The inhibition of ERK activation also circumvented SADS-CoV-induced apoptosis. Taken together, these data suggest that ERK activation is important for SADS-CoV replication, and contributes to the virus-mediated changes in host cells. Our findings demonstrate the takeover of a particular host signaling mechanism by SADS-CoV and identify a potential approach to inhibiting viral spread.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Da Shi
- Corresponding author. Harbin Veterinary Research Institute, CAAS, 678 Haping Road Xiangfang District, Harbin, 150069, China
| | - Li Feng
- Corresponding author. Harbin Veterinary Research Institute, CAAS, 678 Haping Road Xiangfang District, Harbin, 150069, China
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4
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ELK1 Promotes Epithelial-Mesenchymal Transition and the Progression of Lung Adenocarcinoma by Upregulating B7-H3. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2021:2805576. [PMID: 34970415 PMCID: PMC8714344 DOI: 10.1155/2021/2805576] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 11/05/2021] [Accepted: 11/16/2021] [Indexed: 01/06/2023]
Abstract
In previous studies, we found that B7 homolog 3 (B7-H3) was highly expressed in lung adenocarcinoma (LUAD) and promoted epithelial-to-mesenchymal transition (EMT) of LUAD cells. However, the underlying molecular mechanism is unclear. This study is aimed at evaluating the role of Ets-like protein 1 (ELK1) as a transcriptional regulator of B7-H3 for mediating the development and progression of LUAD in vitro and in vivo. We confirmed that ELK1 is highly expressed in LUAD and is associated with poor patient prognosis. ELK1 was found to promote proliferation, invasion, migration, and EMT of LUAD cells through in vivo and in vitro experiments. In terms of mechanism, ELK1 binds to the B7-H3 promoter region and induces the upregulation of B7-H3 in LUAD. Our data suggest that ELK1 plays an important role in the development of LUAD and could be used as a prognostic marker and therapeutic target for LUAD.
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Sun Y, Lin J, Huang S, Xu X, Cai Y, Yang L, Li H, Wu S. Preliminary verification of lncRNA ENST00000609755.1 potential ceRNA regulatory network in coronary heart disease. Int J Cardiol 2020; 328:165-175. [PMID: 33279591 DOI: 10.1016/j.ijcard.2020.11.064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/29/2020] [Accepted: 11/25/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND This study aims to explore the possible ceRNA regulatory network of lncRNA ENST00000609755.1 in CHD patients based on the population; reveal the possible regulatory mechanism of lncRNA ENST00000609755.1. METHOD Microarray analysis were used to identify differentially expressed miRNA, and mRNA profiles between 5 CHD and 5 healthy controls. The lncRNA ENST00000609755.1-miRNA-mRNA ceRNA regulatory network was constructed with lncRNA ENST00000609755.1 as the core based on microarray data and related prediction software (RNAhybird, miRanda, miRWalk 2.0). Furthermore, qRT-PCR was used to verify the expression levels of miRNA and mRNA. t-test and pearson correlation analysis were used to compare the expression differences and correlations of lncRNA, miRNA and mRNA. The receiver operating characteristic (ROC) curve was used to determine the discriminative ability of lncRNA ENST00000609755.1 and its downstream targets. RESULTS Totally 25 miRNAs and 953 mRNAs were differentially expressed between CHD and healthy control. The lncRNA ENST00000609755.1- miRNA- mRNA ceRNA regulatory network was constructed (5 miRNA and 58 mRNA). qRT-PCR results suggest that the expression of lncRNA ENST00000609755.1 and ELK1 were up-regulated in CHD group and positively correlated, the expression of miR-150 was down-regulated in CHD, which was negatively correlated with lncRNA ENST00000609755.1 and ELK1. The AUC was 0.777(95%CI, 0.659-0.895) when miRNA-150 and ELK1 was added, which was higher than that of lncRNA ENST00000609755.1 single indicator. CONCLUSION LncRNA ENST00000609755.1, miR-150 and ELK1 may have a potential ceRNA regulatory network relationship which could be considered to have a good combined diagnostic value for CHD. Also, preliminarily reveal the possible mechanism of lncRNA ENST00000609755.1 involved in CHD.
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Affiliation(s)
- Yi Sun
- Fujian Key Lab of Environmental Factors and Cancer, School of Public Health, Fujian Medical University, China; School of Public Health, Fujian Medical University, Minhou County, Fuzhou, China
| | - Jie Lin
- The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Shuna Huang
- Department of Clinical research and translation center office, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Xingyan Xu
- School of Public Health, Fujian Medical University, Minhou County, Fuzhou, China
| | - Yingying Cai
- School of Public Health, Fujian Medical University, Minhou County, Fuzhou, China
| | - Le Yang
- School of Public Health, Fujian Medical University, Minhou County, Fuzhou, China
| | - Huangyuan Li
- Fujian Key Lab of Environmental Factors and Cancer, School of Public Health, Fujian Medical University, China; School of Public Health, Fujian Medical University, Minhou County, Fuzhou, China.
| | - Siying Wu
- Fujian Key Lab of Environmental Factors and Cancer, School of Public Health, Fujian Medical University, China; Key Lab of Environment and Health, School of Public Health, Fujian Medical University, China.
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6
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EGFR activates GDH1 transcription to promote glutamine metabolism through MEK/ERK/ELK1 pathway in glioblastoma. Oncogene 2020; 39:2975-2986. [PMID: 32034306 DOI: 10.1038/s41388-020-1199-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/26/2020] [Accepted: 01/28/2020] [Indexed: 11/08/2022]
Abstract
Cancer metabolism research has recently been revived and its focus expanded from glucose and the Warburg's effects on other nutrients, such as glutamine. The underlying mechanism of oncogenic alterations of glutaminolysis remains unclear. Genetic alterations of EGFR are observed in ~50% of glioblastoma (GBM) patients, and have been found to play important roles in the metabolic abnormalities of GBM. In this study, we found that glutamine metabolism was upregulated after EGFR activation in a GDH1 (glutamate dehydrogenase 1)-dependent manner. Knockdown of GDH1 significantly reduced the cell proliferation, colony formation and tumorigenesis abilities of glioblastoma cells. Furthermore, we showed that GDH1-mediated glutaminolysis was involved in EGF-promoted cell proliferation. EGFR triggered the phosphorylation of ELK1 at Ser 383 through activating MEK/ERK signaling. Phosphorylated ELK1 enriched in the promoter of GDH1 to activate the transcription of GDH1, which then promoted glutamine metabolism. In addition, EGFR activation did not accelerate glutaminolysis in ELK1 knockdown or ELK1 Ser383-mutated cells. Collectively, our findings indicate that EGFR phosphorylates ELK1 to activate GDH1 transcription and glutaminolysis through MEK/ERK pathway, providing new insight into oncogenic alterations of glutamine metabolism.
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7
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Expression of Phospho-ELK1 and Its Prognostic Significance in Urothelial Carcinoma of the Upper Urinary Tract. Int J Mol Sci 2018. [PMID: 29518027 PMCID: PMC5877638 DOI: 10.3390/ijms19030777] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Using preclinical models, we have recently found that ELK1, a transcriptional factor that activates downstream targets, including c-fos proto-oncogene, induces bladder cancer outgrowth. Here, we immunohistochemically determined the expression status of phospho-ELK1, an activated form of ELK1, in upper urinary tract urothelial carcinoma (UUTUC). Overall, phospho-ELK1 was positive in 47 (47.5%; 37 weak (1+) and 10 moderate (2+)) of 99 UUTUCs, which was significantly (P = 0.002) higher than in benign urothelium (21 (25.3%) of 83; 17 1+ and 4 2+) and was also associated with androgen receptor expression (P = 0.001). Thirteen (35.1%) of 37 non-muscle-invasive versus 34 (54.8%) of 62 muscle-invasive UUTUCs (P = 0.065) were immunoreactive for phospho-ELK1. Lymphovascular invasion was significantly (P = 0.014) more often seen in phospho-ELK1(2+) tumors (80.0%) than in phospho-ELK1(0/1+) tumors (36.0%). There were no statistically significant associations between phospho-ELK1 expression and tumor grade, presence of concurrent carcinoma in situ or hydronephrosis, or pN status. Kaplan-Meier and log-rank tests revealed that patients with phospho-ELK1(2+) tumor had marginally and significantly higher risks of disease progression (P = 0.055) and cancer-specific mortality (P = 0.008), respectively, compared to those with phospho-ELK1(0/1+) tumor. The current results thus support our previous observations in bladder cancer and further suggest that phospho-ELK1 overexpression serves as a predictor of poor prognosis in patients with UUTUC.
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8
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Kuppusamy P, Nagalingam A, Muniraj N, Saxena NK, Sharma D. Concomitant activation of ETS-like transcription factor-1 and Death Receptor-5 via extracellular signal-regulated kinase in withaferin A-mediated inhibition of hepatocarcinogenesis in mice. Sci Rep 2017; 7:17943. [PMID: 29263422 PMCID: PMC5738353 DOI: 10.1038/s41598-017-18190-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 12/07/2017] [Indexed: 12/11/2022] Open
Abstract
Hepatocellular carcinoma (HCC) has the second lowest 5-year survival rate (~16%) of all tumor types partly owing to the lack of effective therapeutic agents. Withaferin A (WA) is a bioactive molecule derived from Withania somnifera and the present study is designed to systemically investigate the anti-HCC efficacy of WA. WA inhibited growth, migration and invasion of HCC cells. Using a phospho-kinase screening array, we discovered that WA increased phosphorylation of ERK and p38 in HCC. Further analyses revealed a key role of ERK leading to increased phosphorylation of p90-ribosomal S6 kinase (RSK) and a concomitant activation of ETS-like transcription factor-1(ELK1) and Death Receptor protein-5 (DR5) in HCC. Importantly, oral administration of WA effectively inhibited HepG2-xenografts and DEN-induced-HCC in C57BL/6 mice. Analyses of WA-treated HepG2-xenografts and DEN-induced-HCC tumors showed elevated levels of ERK, RSK, ELK1 and DR5 along with decreased expression of Ki67. In silico analyses of HCC, utilizing published profiling studies showed an inverse correlation between DR5 and Ki67. These data showed the efficacy of WA as an effective agent for HCC inhibition and provided first in vitro and in vivo evidence supporting the key role of a novel crosstalk between WA, ERK/RSK, ELK1, and DR5 in HCC inhibition.
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Affiliation(s)
- Panjamurthy Kuppusamy
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Arumugam Nagalingam
- Department of Oncology, Johns Hopkins University School of Medicine and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, 21231, USA
| | - Nethaji Muniraj
- Department of Oncology, Johns Hopkins University School of Medicine and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, 21231, USA
| | - Neeraj K Saxena
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Early Detection Research Group, National Cancer Institute, Rockville, MD, USA.
| | - Dipali Sharma
- Department of Oncology, Johns Hopkins University School of Medicine and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, 21231, USA.
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9
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Ye JC, Hsu LS, Tsai JH, Yang HL, Hsiao MW, Hwang JM, Lee CJ, Liu JY. MZF-1/Elk-1/PKCα is Associated with Poor Prognosis in Patients with Hepatocellular Carcinoma. J Cancer 2017; 8:3028-3036. [PMID: 28928894 PMCID: PMC5604454 DOI: 10.7150/jca.20467] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 07/15/2017] [Indexed: 12/20/2022] Open
Abstract
Background: Protein kinase C alpha (PKCα) is a key signaling molecule in human cancer development. As a therapeutic strategy, targeting PKCα is difficult because the molecule is ubiquitously expressed in non-malignant cells. PKCα is regulated by the cooperative interaction of the transcription factors myeloid zinc finger 1 (MZF-1) and Ets-like protein-1 (Elk-1) in human cancer cells. Methods: By conducting tissue array analysis, herein, we determined the protein expression of MZF-1/Elk-1/PKCα in various cancers. Results: The data show that the expression of MZF-1/Elk-1 is correlated with that of PKCα in hepatocellular carcinoma (HCC), but not in bladder and lung cancers. In addition, the PKCα down-regulation by shRNA Elk-1 was only observed in the HCC SK-Hep-1 cells. Blocking the interaction between MZF-1 and Elk-1 through the transfection of their binding domain MZF-160-72 decreased PKCα expression. This step ultimately depressed the epithelial-mesenchymal transition potential of the HCC cells. Conclusion: These findings could be used to develop an alternative therapeutic strategy against patients with the PKCα-derived HCC.
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Affiliation(s)
- Je-Chiuan Ye
- Bachelor Program of Senior Services, Southern Taiwan University of Science and Technology, Tainan, Taiwan
| | - Li-Sung Hsu
- Institute of Biochemistry and Biotechnology, Medical College, Chung-Shan Medical University, Taichung, Taiwan.,Clinical Laboratory, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Jen-Hsiang Tsai
- Department Physical Therapy, School of Medical and Health Sciences, Fooyin University, Kaohsiung, Taiwan
| | - Hsin-Ling Yang
- Institute of Nutrition, College of Biopharmaceutical and Food Sciences, China Medical University, Taichung, Taiwan
| | - Meen-Woon Hsiao
- Department of Medical Applied Chemistry, College of Health Care and Management, Chung Shan Medical University, Taichung, Taiwan
| | - Jin-Ming Hwang
- Department of Medical Applied Chemistry, College of Health Care and Management, Chung Shan Medical University, Taichung, Taiwan
| | - Chia-Jen Lee
- Department of Medical Research, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Jer-Yuh Liu
- Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
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Kawahara T, Shareef HK, Aljarah AK, Ide H, Li Y, Kashiwagi E, Netto GJ, Zheng Y, Miyamoto H. ELK1 is up-regulated by androgen in bladder cancer cells and promotes tumor progression. Oncotarget 2016; 6:29860-76. [PMID: 26342199 PMCID: PMC4745768 DOI: 10.18632/oncotarget.5007] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/12/2015] [Indexed: 12/15/2022] Open
Abstract
Little is known about biological significance of ELK1, a transcriptional factor that activates downstream targets including c-fos proto-oncogene, in bladder cancer. Recent preclinical evidence also suggests the involvement of androgen receptor (AR) signaling in bladder cancer progression. In this study, we aim to investigate the functions of ELK1 in bladder cancer growth and their regulation by AR signals. Immunohistochemistry in bladder tumor specimens showed that the levels of phospho-ELK1 (p-ELK1) expression were significantly elevated in urothelial neoplasms, compared with non-neoplastic urothelium tissues, and were also correlated with AR positivity. Patients with p-ELK1-positive non-muscle-invasive and muscle-invasive tumors had significantly higher risks for tumor recurrence and progression, respectively. In AR-positive bladder cancer cell lines, dihydrotestosterone treatment increased ELK1 expression (mRNA, protein) and its nuclear translocation, ELK1 transcriptional activity, and c-fos expression, which was restored by an anti-androgen hydroxyflutamide. ELK1 silencing via short hairpin RNA (shRNA) resulted in decreases in cell viability/colony formation, and cell migration/invasion as well as an increase in apoptosis. Importantly, ELK1 appears to require activated AR to regulate bladder cancer cell proliferation, but not cell migration. Androgen also failed to significantly induce AR transactivation in ELK1-knockdown cells. In accordance with our in vitro findings, ELK1-shRNA expression considerably retarded tumor formation as well as its growth in xenograft-bearing male mice. Our results suggest that ELK1 plays an important role in bladder tumorigenesis and cancer progression, which is further induced by AR activation. Accordingly, ELK1 inhibition, together with AR inactivation, has the potential of being a therapeutic approach for bladder cancer.
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Affiliation(s)
- Takashi Kawahara
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA.,Department of Urology, Yokohama City University School of Medicine, Yokohama, Japan
| | - Hasanain Khaleel Shareef
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Biology, University of Babylon College of Science for Women, Babylon, Iraq
| | - Ali Kadhim Aljarah
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Biology, University of Baghdad College of Science, Baghdad, Iraq
| | - Hiroki Ide
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yi Li
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA.,Department of Urology, 2nd Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Eiji Kashiwagi
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - George J Netto
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yichun Zheng
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA.,Department of Urology, 2nd Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Hiroshi Miyamoto
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
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11
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Kawahara T, Aljarah AK, Shareef HK, Inoue S, Ide H, Patterson JD, Kashiwagi E, Han B, Li Y, Zheng Y, Miyamoto H. Silodosin inhibits prostate cancer cell growth via ELK1 inactivation and enhances the cytotoxic activity of gemcitabine. Prostate 2016; 76:744-56. [PMID: 26864615 DOI: 10.1002/pros.23164] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 01/22/2016] [Indexed: 11/06/2022]
Abstract
BACKGROUND Biological significance of ELK1, a transcriptional factor whose phosphorylation is necessary for c-fos proto-oncogene activation, in prostate cancer remains far from fully understood. In this study, we aim to investigate the role of ELK1 in tumor growth as well as the efficacy of a selective α1A-adrenergic blocker, silodosin, in ELK1 activity in prostate cancer cells. METHODS We first immunohistochemically determined the levels of phospho-ELK1 (p-ELK1) expression in radical prostatectomy specimens. We then assessed the effects of ELK1 knockdown via short hairpin RNA and silodosin on cell proliferation, migration, and invasion in prostate cancer lines. RESULTS The levels of p-ELK1 expression were significantly higher in carcinoma than in benign (P < 0.001) or high-grade prostatic intraepithelial neoplasia (HGPIN) (P = 0.002) as well as in HGPIN than in benign (P < 0.001). Kaplan-Meier and log-rank tests revealed that moderate-strong positivity of p-ELK1 in carcinomas tended to correlate with biochemical recurrence after radical prostatectomy (P = 0.098). In PC3 and DU145 expressing ELK1 (mRNA/protein) but no androgen receptor (AR), ELK1 silencing resulted in considerable decreases in the expression of c-fos as well as in cell migration/invasion and matrix metalloproteinase-2 expression, but not in cell viability. Silodosin treatment reduced the expression/activity of ELK1 in these cells as well as the viability of AR-positive LNCaP and C4-2 cells and the migration of both AR-positive and AR-negative cells, but not the viability of AR-negative or ELK1-negative cells. Interestingly, silodosin significantly increased sensitivity to gemcitabine, but not to cisplatin or docetaxel, even in AR-negative cells. CONCLUSIONS ELK1 is likely to be activated in prostate cancer cells and promote tumor progression. Furthermore, silodosin that inactivates ELK1 in prostate cancer cells not only inhibits their growth but also enhances the cytotoxic activity of gemcitabine. Thus, ELK1 inhibition has the potential of being a therapeutic approach for prostate cancer.
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Affiliation(s)
- Takashi Kawahara
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York
- Department of Urology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Ali Kadhim Aljarah
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Biology, University of Baghdad College of Science, Baghdad, Iraq
| | - Hasanain Khaleel Shareef
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Biology, University of Babylon College of Science for Women, Babylon, Iraq
| | - Satoshi Inoue
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hiroki Ide
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - John D Patterson
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Eiji Kashiwagi
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Bin Han
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yi Li
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York
| | - Yichun Zheng
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York
| | - Hiroshi Miyamoto
- Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York
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12
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MZF-1/Elk-1 Complex Binds to Protein Kinase Cα Promoter and Is Involved in Hepatocellular Carcinoma. PLoS One 2015; 10:e0127420. [PMID: 26010542 PMCID: PMC4444300 DOI: 10.1371/journal.pone.0127420] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/14/2015] [Indexed: 01/28/2023] Open
Abstract
In this study, the molecular mechanism of protein kinase C alpha (PKCα) gene regulation in hepatocellular carcinoma (HCC) involving Ets-like protein-1 (Elk-1) and myeloid zinc finger-1 (MZF-1) was investigated. The luciferase reporter assay results revealed that the presence of both MZF-1 and Elk-1 significantly contributed to the upregulation of PKCα gene transcription activity, and the transcriptional activity decreased when the transfection included a DNA-binding-deficient (∆DBD) gene vector of either MZF-1 or Elk-1 DNA-binding deficiency (MZF-1∆DBD or Elk-1∆DBD), thereby indicating that the enhanced expression of PKCα was caused by the binding of MZF-1 and/or Elk-1 with the PKCα promoter. We investigated MZF-1 and Elk-1 to determine whether they bind to each other. The results of immunoprecipitation (IP), Co-IP, chromatin IP (ChIP), and Re-ChIP analyses indicated that Elk-1 can directly bind to the N-terminal region of MZF-1 and MZF-1 can directly bind to the C-terminal region of Elk-1 to form a complex before attaching to the PKCα promoter. Furthermore, when MZF-1∆DBD or Elk-1∆DBD was added to the cells, PKCα expression decreased, and cell proliferation, migration, invasion, and tumorigenicity also decreased. These findings suggest that PKCα expression in HCC could be stimulated by the formation of MZF-1/Elk-1 complex, which directly binds to the PKCα promoter.
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13
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Nagalingam A, Kuppusamy P, Singh SV, Sharma D, Saxena NK. Mechanistic elucidation of the antitumor properties of withaferin a in breast cancer. Cancer Res 2014; 74:2617-29. [PMID: 24732433 DOI: 10.1158/0008-5472.can-13-2081] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Withaferin A (WFA) is a steroidal lactone with antitumor effects manifested at multiple levels that are mechanistically obscure. Using a phospho-kinase screening array, we discovered that WFA activated phosphorylation of the S6 kinase RSK (ribosomal S6 kinase) in breast cancer cells. Pursuing this observation, we defined activation of extracellular signal-regulated kinase (ERK)-RSK and ETS-like transcription factor 1 (Elk1)-CHOP (C-EBP homologous protein) kinase pathways in upregulating transcription of the death receptor 5 (DR5). Through this route, WFA acted as an effective DR5 activator capable of potentiating the biologic effects of celecoxib, etoposide, and TRAIL. Accordingly, WFA treatment inhibited breast tumor formation in xenograft and mouse mammary tumor virus (MMTV)-neu mouse models in a manner associated with activation of the ERK/RSK axis, DR5 upregulation, and elevated nuclear accumulation of Elk1 and CHOP. Together, our results offer mechanistic insight into how WFA inhibits breast tumor growth.
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Affiliation(s)
- Arumugam Nagalingam
- Authors' Affiliations: Department of Oncology, Johns Hopkins University School of Medicine and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins; Department of Medicine, University of Maryland School of Medicine, Baltimore Maryland; and Department of Pharmacology and Chemical Biology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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14
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Teixeira FR, Manfiolli AO, Soares CS, Baqui MMA, Koide T, Gomes MD. The F-box protein FBXO25 promotes the proteasome-dependent degradation of ELK-1 protein. J Biol Chem 2013; 288:28152-62. [PMID: 23940030 DOI: 10.1074/jbc.m113.504308] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
FBXO25 is one of the 69 known human F-box proteins that serve as specificity factors for a family of ubiquitin ligases composed of SKP1, Rbx1, Cullin1, and F-box protein (SCF1) that are involved in targeting proteins for degradation across the ubiquitin proteasome system. However, the substrates of most SCF E3 ligases remain unknown. Here, we applied an in chip ubiquitination screen using a human protein microarray to uncover putative substrates for the FBXO25 protein. Among several novel putative targets identified, the c-fos protooncogene regulator ELK-1 was characterized as the first endogenous substrate for SCF1(FBXO25) E3 ligase. FBXO25 interacted with and mediated the ubiquitination and proteasomal degradation of ELK-1 in HEK293T cells. In addition, FBXO25 overexpression suppressed induction of two ELK-1 target genes, c-fos and egr-1, in response to phorbol 12-myristate 13-acetate. Together, our findings show that FBXO25 mediates ELK-1 degradation through the ubiquitin proteasome system and thereby plays a role in regulating the activation of ELK-1 pathway in response to mitogens.
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15
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Bruck T, Yanuka O, Benvenisty N. Human pluripotent stem cells with distinct X inactivation status show molecular and cellular differences controlled by the X-Linked ELK-1 gene. Cell Rep 2013; 4:262-70. [PMID: 23871667 DOI: 10.1016/j.celrep.2013.06.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 06/02/2013] [Accepted: 06/24/2013] [Indexed: 10/26/2022] Open
Abstract
Female human pluripotent stem cells show vast heterogeneity regarding the status of X chromosome inactivation. By comparing the gene expression profile of cells with two active X chromosomes (XaXa cells) to that of cells with only one active X chromosome (XaXi cells), a set of autosomal genes was shown to be overexpressed in the XaXa cells. Among these genes, we found significant enrichment for genes regulated by the X-linked transcription factor ELK-1. Comparison of the phenotype of XaXa and XaXi cells demonstrated differences in programmed cell death and differentiation, implying some growth disadvantage of the XaXa cells. Interestingly, ELK-1-overexpressing cells mimicked the phenotype of XaXa cells, whereas knockdown of ELK-1 with small hairpin RNA mimicked the phenotype of XaXi cells. When cultured at low oxygen levels, these cellular differences were considerably weakened. Our analysis implies a role of ELK-1 in the differences between pluripotent stem cells with distinct X chromosome inactivation statuses.
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Affiliation(s)
- Tal Bruck
- Stem Cell Unit, Department of Genetics, Institute of Life Sciences, The Hebrew University, Jerusalem 91904, Israel
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16
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Laliotis A, Vrekoussis T, Kafousi M, Sanidas E, Askoxilakis J, Melissas J, Mavroudis D, Castanas E, Stathopoulos EN. Immunohistochemical study of pElk-1 expression in human breast cancer: association with breast cancer biologic profile and clinicopathologic features. Breast 2012; 22:89-95. [PMID: 23127278 DOI: 10.1016/j.breast.2012.09.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 09/10/2012] [Accepted: 09/23/2012] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Recently an increased interest on Elk1 protein and its role in breast cancer evolution has been noted. This protein is an element of the Ets family of transcription factors and it has been involved in a number of important cell processes through the activation of different genes, in a number of normal tissues as well as in many malignancies. METHODS One hundred and seventy (n = 170) cases of operable breast cancer (invasive ductal, lobular and mixed type breast carcinomas) were randomly selected and investigated for the expression of pElk-1, Ki-67 and Cyclin D1 using immunohistochemistry. Our findings were correlated with tumors' clinicopathologic data and biologic profile. RESULTS Activated Elk1 is positively associated with ER (p-value: 0.018) and also shows a positive association of with Cyclin D1 (p-value: <0.001). No relationship was noted between pElk1 and Ki67 (p-value: 0.213). Luminal A and B Her-2 negative breast cancer subtypes were showing greater pElk-1 immunoreactivity compared to Her-2 and Basal breast cancer subtypes, and also a higher staining intensity. No association of the molecule with other clinicopathologic characteristics (tumor size, stage, histological type or lymph node metastases) or disease adverse events (local recurrence, metastasis or death) was evidenced. CONCLUSIONS Our findings offer a new perspective for the role of pElk-1 in breast neoplasia suggesting a direct relation of this molecule to tumor biology and a putative target of personalized breast cancer therapies, although its prognostic/discriminant role is not supported.
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Affiliation(s)
- Aggelos Laliotis
- Department of Surgical Oncology, University of Crete, School of Medicine, Heraklion, Greece
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17
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Morris JF, Sul JY, Kim MS, Klein-Szanto AJ, Schochet T, Rustgi A, Eberwine JH. Elk-1 phosphorylated at threonine-417 is present in diverse cancers and correlates with differentiation grade of colonic adenocarcinoma. Hum Pathol 2012; 44:766-76. [PMID: 23114923 DOI: 10.1016/j.humpath.2012.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 08/03/2012] [Accepted: 08/03/2012] [Indexed: 01/18/2023]
Abstract
Elk-1 is a member of the Ets family of transcription factors, which are identified by a conserved Ets DNA-binding domain that mediates transcriptional regulation at Ets sequence--containing promoters. The activation domain of Elk-1 is important for executing its physiologic functions and contains many phosphorylation sites targeted by various MAP kinases following exposure to cell stressors or mitogenic stimuli. The different combinations of phosphorylated sites allow specificity of cellular responses mediated through redundant signaling pathways activated by distinct stimuli. Through phosphorylation of S383, mitogen-activated protein kinase (MAPK)-activating stimuli have been shown to regulate various processes important in carcinogenesis through transcriptional regulation in various cell lines, including proliferation. Phosphorylation at the T417 site (pT417), but not the S383 site, is involved in neuronal apoptosis induced through dendritic signaling mechanisms and associates with neuronal lesions in many Lewy body diseases. This points to distinct roles for these different phosphorylation sites in pathophysiologic pathways. However, the S383 site remains the best characterized in the context of normal function and carcinogenesis in cell lines, and less is known about the biochemistry of other phosphorylation sites, particularly in more biochemically relevant models. Here, we show that Elk-1 pT417 is present in epithelial cell nuclei of various normal and cancer tissues and that the number of pT417-positive cells correlates with differentiation grade of colonic adenocarcinomas. This nuclear localization and correlation with tumor differentiation in adenocarcinoma suggests a potentially important transcriptional and biochemical role of this phosphorylation site in carcinogenesis of this tumor type.
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Affiliation(s)
- Jacqueline F Morris
- Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104, USA
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18
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Li MY, Lai FJ, Hsu LJ, Lo CP, Cheng CL, Lin SR, Lee MH, Chang JY, Subhan D, Tsai MS, Sze CI, Pugazhenthi S, Chang NS, Chen ST. Dramatic co-activation of WWOX/WOX1 with CREB and NF-kappaB in delayed loss of small dorsal root ganglion neurons upon sciatic nerve transection in rats. PLoS One 2009; 4:e7820. [PMID: 19918364 PMCID: PMC2771921 DOI: 10.1371/journal.pone.0007820] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 10/17/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Tumor suppressor WOX1 (also named WWOX or FOR) is known to participate in neuronal apoptosis in vivo. Here, we investigated the functional role of WOX1 and transcription factors in the delayed loss of axotomized neurons in dorsal root ganglia (DRG) in rats. METHODOLOGY/PRINCIPAL FINDINGS Sciatic nerve transection in rats rapidly induced JNK1 activation and upregulation of mRNA and protein expression of WOX1 in the injured DRG neurons in 30 min. Accumulation of p-WOX1, p-JNK1, p-CREB, p-c-Jun, NF-kappaB and ATF3 in the nuclei of injured neurons took place within hours or the first week of injury. At the second month, dramatic nuclear accumulation of WOX1 with CREB (>65% neurons) and NF-kappaB (40-65%) occurred essentially in small DRG neurons, followed by apoptosis at later months. WOX1 physically interacted with CREB most strongly in the nuclei as determined by FRET analysis. Immunoelectron microscopy revealed the complex formation of p-WOX1 with p-CREB and p-c-Jun in vivo. WOX1 blocked the prosurvival CREB-, CRE-, and AP-1-mediated promoter activation in vitro. In contrast, WOX1 enhanced promoter activation governed by c-Jun, Elk-1 and NF-kappaB. WOX1 directly activated NF-kappaB-regulated promoter via its WW domains. Smad4 and p53 were not involved in the delayed loss of small DRG neurons. CONCLUSIONS/SIGNIFICANCE Rapid activation of JNK1 and WOX1 during the acute phase of injury is critical in determining neuronal survival or death, as both proteins functionally antagonize. In the chronic phase, concurrent activation of WOX1, CREB, and NF-kappaB occurs in small neurons just prior to apoptosis. Likely in vivo interactions are: 1) WOX1 inhibits the neuroprotective CREB, which leads to eventual neuronal death, and 2) WOX1 enhances NF-kappaB promoter activation (which turns to be proapoptotic). Evidently, WOX1 is the potential target for drug intervention in mitigating symptoms associated with neuronal injury.
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Affiliation(s)
- Meng-Yen Li
- Department of Cell Biology & Anatomy, National Cheng Kung
University Medical College, Tainan, Taiwan
| | - Feng-Jie Lai
- Department of Dermatology, Chi-Mei Medical Center, Tainan,
Taiwan
| | - Li-Jin Hsu
- Department of Microbiology & Immunology, National Cheng Kung
University Medical College, Tainan, Taiwan
- Center for Gene Regulation and Signal Transduction Research, National
Cheng Kung University Medical College, Tainan, Taiwan
| | - Chen-Peng Lo
- Department of Cell Biology & Anatomy, National Cheng Kung
University Medical College, Tainan, Taiwan
- Institute of Basic Medical Science, National Cheng Kung University
Medical College, Tainan, Taiwan
| | - Ching-Li Cheng
- Institute of Basic Medical Science, National Cheng Kung University
Medical College, Tainan, Taiwan
| | - Sing-Ru Lin
- Institute of Molecular Medicine, National Cheng Kung University Medical
College, Tainan, Taiwan
| | - Ming-Hui Lee
- Institute of Molecular Medicine, National Cheng Kung University Medical
College, Tainan, Taiwan
| | - Jean-Yun Chang
- Institute of Molecular Medicine, National Cheng Kung University Medical
College, Tainan, Taiwan
| | - Dudekula Subhan
- Institute of Molecular Medicine, National Cheng Kung University Medical
College, Tainan, Taiwan
| | - Ming-Shu Tsai
- Putz General Hospital, Department of Health, Executive Yuan, Chiayi,
Taiwan
| | - Chun-I Sze
- Department of Cell Biology & Anatomy, National Cheng Kung
University Medical College, Tainan, Taiwan
| | - Subbiah Pugazhenthi
- Department of Medicine, University of Colorado at Denver and Health
Sciences Center, Aurora, Colorado, United States of America
| | - Nan-Shan Chang
- Center for Gene Regulation and Signal Transduction Research, National
Cheng Kung University Medical College, Tainan, Taiwan
- Institute of Basic Medical Science, National Cheng Kung University
Medical College, Tainan, Taiwan
- Institute of Molecular Medicine, National Cheng Kung University Medical
College, Tainan, Taiwan
- Department of Neuroscience and Physiology, SUNY Upstate Medical
University, Syracuse, New York, United States of America
| | - Shur-Tzu Chen
- Department of Cell Biology & Anatomy, National Cheng Kung
University Medical College, Tainan, Taiwan
- Department of Dermatology, Chi-Mei Medical Center, Tainan,
Taiwan
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19
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Maniccia AW, Lewis C, Begum N, Xu J, Cui J, Chipitsyna G, Aysola K, Reddy V, Bhat G, Fujimura Y, Henderson B, Reddy ESP, Rao VN. Mitochondrial localization, ELK-1 transcriptional regulation and growth inhibitory functions of BRCA1, BRCA1a, and BRCA1b proteins. J Cell Physiol 2009; 219:634-41. [PMID: 19170108 DOI: 10.1002/jcp.21708] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BRCA1 is a tumor suppressor gene that is mutated in families with breast and ovarian cancer. Several BRCA1 splice variants are found in different tissues, but their subcellular localization and functions are poorly understood at the moment. We previously described BRCA1 splice variant BRCA1a to induce apoptosis and function as a tumor suppressor of triple negative breast, ovarian and prostate cancers. In this study we have analyzed the function of BRCA1 isoforms (BRCA1a and BRCA1b) and compared them to the wild-type BRCA1 protein using several criteria like studying expression in normal and tumor cells by RNase protection assays, subcellular localization/fractionation by immunofluorescence microscopy and Western blot analysis, transcription regulation of biological relevant proteins and growth suppression in breast cancer cells. We are demonstrating for the first time that ectopically expressed GFP-tagged BRCA1, BRCA1a, and BRCA1b proteins are localized to the mitochondria, repress ELK-1 transcriptional activity and possess antiproliferative activity on breast cancer cells. These results suggest that the exon 9, 10, and 11 sequences (aa 263-1365) which contain two nuclear localization signals, p53, Rb, c-Myc, gamma-tubulin, Stat, Rad51, Rad50 binding domains, angiopoietin-1 repression domain are not absolutely required for mitochondrial localization and growth suppressor function of these proteins. Since mitochondrial dysfunction is a hallmark of cancer, we can speculate that the mitochondrial localization of BRCA1 proteins may be functionally significant in regulating both the mitochondrial DNA damage as well as apoptotic activity of BRCA1 proteins and mislocalization causes cancer. J. Cell. Physiol. 219: 634-641, 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Anna W Maniccia
- Cancer Biology Program, Department of OB/GYN, Morehouse School of Medicine, Georgia Cancer Center for Excellence, Atlanta, Georgia, USA
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20
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Dae HM, Kwon HY, Kang NY, Song NR, Kim KS, Kim CH, Lee JH, Lee YC. Isolation and functional analysis of the human glioblastoma-specific promoter region of the human GD3 synthase (hST8Sia I) gene. Acta Biochim Biophys Sin (Shanghai) 2009; 41:237-45. [PMID: 19280063 DOI: 10.1093/abbs/gmp007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We identified the promoter region of the human GD3 synthase (hST8Sia I) gene to elucidate the mechanism underlying the regulation of hST8Sia I expression in human glioblastoma cells. The 5'-rapid amplification of cDNA end using mRNA prepared from U-87MG cells revealed the presence of transcription start site of hST8Sia I gene, and the 5'-terminal analysis of its product showed that transcription started from 648 nucleotides upstream of the translational initiation site. Functional analysis of the 5'-flanking region of the hST8Sia I gene by transient expression method revealed that the region from -638 to -498 is important for transcriptional activity of the hST8Sia I gene in U-87MG and T98G cells. This region lacks apparent TATA and CAAT boxes, but contains putative binding sites for transcription factors AREB6 and Elk-1. Site-directed mutagenesis and transient transfection assays demonstrated that both AREB6 and Elk-1 elements in this region were required for the promoter activity in U-87MG and T98G cells. These results indicated that both AREB6 and Elk-1 might play an essential role in the transcriptional activity of hST8Sia I gene essential for GD3 synthesis in human glioblastoma cells.
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Affiliation(s)
- Hyun-Mi Dae
- College of Natural Resources and Life Science, BK21 Center for Silver-Bio Industrialization, Dong-A University, Busan 604-714, South Korea
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21
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Jiang J, Yang W, Huang P, Bu X, Zhang N, Li J. Increased Phosphorylation of Ets-like Transcription Factor-1 in Neurons of Hypoxic Preconditioned Mice. Neurochem Res 2009; 34:1443-50. [DOI: 10.1007/s11064-009-9931-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 02/04/2009] [Indexed: 11/28/2022]
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Mamali I, Kotsantis P, Lampropoulou M, Marmaras VJ. Elk-1 associates with FAK, regulates the expression of FAK and MAP kinases as well as apoptosis in HK-2 cells. J Cell Physiol 2008; 216:198-206. [PMID: 18247360 DOI: 10.1002/jcp.21390] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Focal adhesion kinase (FAK), MAP kinases and the nuclear transcription factor Elk-1 have been reported to be implicated in the same cellular processes, however, their direct or indirect interaction and potential function(s) has not been documented. Here, we explored the association of FAK with Elk-1, the implication of Elk-1 in the regulation of FAK and MAP kinases expression as well as apoptosis, in HK-2 cells. Biochemical and immunofluorescence approaches strongly support the association of low molecular weight protein bands, recognized by FAK antibodies, with Elk-1 or p(ser383)Elk-1. The FAK/Elk-1 complex is found, mainly, in the cytoplasm, near the nuclear membrane periphery, raising the possibility that Elk-1 may have alternative extranuclear function(s) in HK-2 cells. Furthermore, we demonstrated that Elk-1 siRNA-mediated knockdown experiments, increased apoptosis. By contrast, Elk-1 siRNA decreased significantly the expression of FAK and MAP kinases, supporting the hypothesis that Elk-1 may act as a potential physiological substrate and regulator of FAK and MAP kinases expression. These results strongly support that Elk-1 protein is a novel binding-protein partner for FAK, a finding that significantly broadens the potential functioning of FAK and Elk-1.
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Affiliation(s)
- Irene Mamali
- Department of Biology, University of Patras, Patras, Greece
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23
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LaCasse RA, Striebel JF, Favara C, Kercher L, Chesebro B. Role of Erk1/2 activation in prion disease pathogenesis: absence of CCR1 leads to increased Erk1/2 activation and accelerated disease progression. J Neuroimmunol 2008; 196:16-26. [PMID: 18396336 DOI: 10.1016/j.jneuroim.2008.02.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 01/16/2008] [Accepted: 02/11/2008] [Indexed: 12/14/2022]
Abstract
Prion diseases are neurodegenerative infections with gliosis and vacuolation. The mechanisms of degeneration remain unclear, but chemokines may be important. In current experiments CCR1 knock-out (KO) mice succumbed more rapidly to scrapie infection than WT controls. Infected KO mice had upregulation of CCL3, a CCR1 ligand, and CCR5, a receptor with specificity for CCL3. Both infected KO and WT mice had upregulation of CCR5-mediated signaling involving activation of Erk1/2 in astrocytes; however, activation was earlier in KO mice suggesting a role in pathogenesis. In both mouse strains activation of the Erk1/2 pathway may lead to astrocyte dysfunction resulting in neurodegeneration.
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Affiliation(s)
- Rachel A LaCasse
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT 59840, United States
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Elk-1 is a novel protein-binding partner for FAK, regulating phagocytosis in medfly hemocytes. J Cell Biochem 2008; 103:1895-911. [DOI: 10.1002/jcb.21580] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Antisense oligonucleotide Elk-1 suppresses the tumorigenicity of human hepatocellular carcinoma cells. Cell Biol Int 2007; 32:210-6. [PMID: 17950002 DOI: 10.1016/j.cellbi.2007.08.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 08/03/2007] [Accepted: 08/29/2007] [Indexed: 11/20/2022]
Abstract
In previous studies, we showed that reducing Ets-like protein-1 (Elk-1) expression inhibited protein kinase C alpha (PKC alpha) expression and decreased cell migration and invasion in human hepatocellular carcinoma (HCC). In this study, we have investigated the role of Elk-1 in tumorigenesis. SK-Hep-1 HCC cells were transfected with the ElK-1 antisense oligonucleotide (ODN). In the pretreated cells we detected a reduction of mRNA level using RT-PCR. The inhibitory rate of cell growth was measured by MTT assay. Pretreated-SK-Hep-1 HCC cells were implanted subcutaneously into nude mice to observe the tumor growth and calculate tumor inhibitory rate. The results showed that 5 microM of the antisense ODN Elk-1 suppressed both Elk-1 and PKC alpha production by SK-Hep-1 HCC cells after cationic liposome-mediated transfection, to 8% and 1% of control values, respectively, and the growth of SK-Hep-1 HCC cells was inhibited at 2-5 microM doses of the antisense ODN Elk-1. The control reagent, sense ODN Elk-1, showed no effects. In BALB/nude mice, SK-Hep-1 HCC cells transfected with the 5 microM antisense ODN Elk-1 formed tumors much smaller than those of sense ODN Elk-1 pretreated cells. The maximum inhibitory rate of tumor growth was 80.8+/-12.6% and the tumor formation time was prolonged from 13 to 25 days. These findings suggested the usefulness of antisense ODN Elk-1 as a new reagent for liver cancer therapy.
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Chen AG, Yu ZC, Yu XF, Cao WF, Ding F, Liu ZH. Overexpression of Ets-like protein 1 in human esophageal squamous cell carcinoma. World J Gastroenterol 2006; 12:7859-63. [PMID: 17203534 PMCID: PMC4087556 DOI: 10.3748/wjg.v12.i48.7859] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To study the expression pattern of Ets-like protein 1 (Elk-1) in human esophageal squamous cell carcinoma (ESCC) and to analyze its relationship with clinicopathologic parameters.
METHODS: The expression of Elk-1 in fresh esophageal cancer tissues and their corresponding normal mucosae was detected immunohistochemically (IHC) by means of tissue microarray (TMA). Its correlation with clinical characteristics was evaluated and analyzed by univariate analysis. All statistical analyses were performed by SPSS version 13.0.
RESULTS: Expression level of transcription factor Elk-1 increased in 78.5% (84/107) ESCC tissues compared with their matched normal esophageal epithelium. However, the expression of Elk-1 did not show any obvious correlation with degree of differentiation of esophageal carcinoma (in well-differentiated, moderately-differentiated and poorly-differentiated tumors, the increased expression was 7/8, 60/74, and 19/25, respectively, P > 0.05). Moreover, no obvious correlation was found with lymph node metastasis and depth of invasion.
CONCLUSION: Increased expression of transcription factor Elk-1 may play an important role in esophageal carcinogenesis.
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Affiliation(s)
- An-Guo Chen
- Department of Thoracic Surgery, First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui Province, China
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Hollmann CA, Owens T, Nalbantoglu J, Hudson TJ, Sladek R. Constitutive Activation of Extracellular Signal-Regulated Kinase Predisposes Diffuse Large B-Cell Lymphoma Cell Lines to CD40-Mediated Cell Death. Cancer Res 2006; 66:3550-7. [PMID: 16585179 DOI: 10.1158/0008-5472.can-05-2498] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
CD40 promotes survival, proliferation, and differentiation of normal B cells but can cause activation-induced cell death in malignant B lymphocytes. CD40 ligand and anti-CD40 antibodies have been used successfully to induce apoptosis in lymphoma lines both in vitro and in xenograft tumor models. Although this makes CD40 an attractive target for antitumor therapies, the response of malignant B cells to CD40 signaling is variable, and CD40 stimulation can enhance proliferation and can increase chemoresistance in some cell lines. It would therefore be useful to identify markers that predict whether a specific cell line or tumor will undergo apoptosis when stimulated with CD40 and to identify targets downstream of CD40 that affect only the apoptotic arm of CD40 signaling. We have analyzed gene expression patterns in CD40-sensitive and CD40-resistant diffuse large B-cell lymphoma (DLBCL) cell lines to identify signaling pathways that are involved in CD40-mediated apoptosis. CD40-resistant lines expressed pre-B-cell markers, including RAG and VPREB, whereas CD40-sensitive cells resembled mature B cells and expressed higher levels of transcripts encoding several members of the CD40 signaling pathway, including LCK and VAV. In addition, CD40-sensitive DLBCL cell lines also displayed constitutive activation of extracellular signal-regulated kinase (ERK) and failed to undergo apoptosis when ERK phosphorylation was inhibited. In contrast, CD40-resistant lines showed no constitutive activation of ERK and no increase in ERK activity in response to CD40 stimulation. Our results suggest that constitutive activation of ERK may be required for death signaling by CD40.
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Affiliation(s)
- C Annette Hollmann
- Neuroimmunology Unit, Montreal Neurological Institute, Departments of Medicine and Human Genetics, McGill University, Duff Medical Bldg. Room 717, 3775 University Street, Montreal, Quebec, Canada H3A 2B4.
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28
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Barrett LE, Van Bockstaele EJ, Y. Sul J, Takano H, Haydon PG, Eberwine JH. Elk-1 associates with the mitochondrial permeability transition pore complex in neurons. Proc Natl Acad Sci U S A 2006; 103:5155-60. [PMID: 16549787 PMCID: PMC1458810 DOI: 10.1073/pnas.0510477103] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
The nuclear transcription factor E-26-like protein 1 (Elk-1) is thought to impact neuronal differentiation [Sharrocks, A. D. (2001) Nat. Rev. Mol. Cell Biol. 2, 827-837], cell proliferation [Sharrocks, A. D. (2002) Biochem. Soc. Trans. 30, 1-9], tumorigenesis [Chai, Y. L., Chipitsyna, G., Cui, J., Liao, B., Liu, S., Aysola, K., Yezdani, M., Reddy, E. S. P. & Rao, V. N. (2001) Oncogene 20, 1357-1367], and apoptosis [Shao, N., Chai, Y., Cui, J., Wang, N., Aysola, K., Reddy, E. S. P. & Rao, V. N. (1998) Oncogene 17, 527-532]. In addition to its nuclear localization, Elk-1 is found throughout the cytoplasm, including localization in neuronal dendrites [Sgambato, V., Vanhoutte, P., Pages, C., Rogard, M., Hipskind, R., Besson, M. J. & Caboche, J. (1998) J. Neurosci. 18, 214-226], raising the possibility that Elk-1 may have alternative extranuclear functions in neurons. Using coimmunoprecipitation and reciprocal coimmunoprecipitation from adult rat brain, we found an association between Elk-1 protein and the mitochondrial permeability transition pore complex (PTP), a structure involved in both apoptotic and necrotic cell death. Electron microscopy in adult rat brain sections confirmed this association with mitochondria. Elk-1 was also identified from purified mitochondrial fractions by using Western blotting, and Elk-1 increased its association with mitochondria following proapoptotic stimuli. Consistent with a role for Elk-1 in neuron viability, overexpression of Elk-1 in primary neurons decreased cell viability, whereas Elk-1 siRNA-mediated knockdown increased cell viability. This decrease in viability induced by Elk-1 overexpression was blocked with application of a PTP inhibitor. These results show an association of the nuclear transcription factor Elk-1 with the mitochondrial PTP and suggest an additional extranuclear function for Elk-1 in neurons.
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Affiliation(s)
| | - E. J. Van Bockstaele
- Department of Neurosurgery, Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107
| | | | | | | | - J. H. Eberwine
- Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104; and
- To whom correspondence should be addressed. E-mail:
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Subramaniam S, Unsicker K. Extracellular signal-regulated kinase as an inducer of non-apoptotic neuronal death. Neuroscience 2006; 138:1055-65. [PMID: 16442236 DOI: 10.1016/j.neuroscience.2005.12.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 11/23/2005] [Accepted: 12/01/2005] [Indexed: 11/17/2022]
Abstract
Extracellular signal-regulated kinase (ERK) is a versatile protein kinase, which has been implicated in signaling numerous biological functions ranging from embryonic development to memory formation. Recent reports, including ours, indicate that ERK plays a central role in promoting neuronal degeneration in various neuronal systems including neurodegenerative diseases. Mechanisms involved in ERK-induced neuronal degeneration are beginning to emerge. In this review, we summarize evidence suggesting ERK to be a predominant inducer of a non-apoptotic mode of neuronal death. Further, we discuss the mechanisms and the putative molecular inter-players associated with ERK-mediated neuronal death.
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Affiliation(s)
- S Subramaniam
- Neuroanatomy and Interdisciplinary Center for Neurosciences, University of Heidelberg, Im Neuenheimer Feld 307, D-69120, Heidelberg, Germany.
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30
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Hsieh YH, Wu TT, Tsai JH, Huang CY, Hsieh YS, Liu JY. PKCalpha expression regulated by Elk-1 and MZF-1 in human HCC cells. Biochem Biophys Res Commun 2005; 339:217-25. [PMID: 16297876 DOI: 10.1016/j.bbrc.2005.11.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Accepted: 11/02/2005] [Indexed: 11/30/2022]
Abstract
Our previous study found that PKCalpha was highly expressed in the poor-differentiated human HCC cells and associated with cell migration and invasion. In this study, we further investigated the gene regulation of this enzyme. We showed that PKCalpha expression enhancement in the poor-differentiated human HCC cells was found neither by DNA amplification nor by increasing mRNA stability using differential PCR and mRNA decay assays. After screening seven transcription factors in the putative cis-acting regulatory elements of human PKCalpha promoters, only Elk-1 and MZF-1 antisense oligonucleotide showed a significant reduction in the PKCalpha mRNA level. They also reduced cell proliferation, cell migratory and invasive capabilities, and DNA binding activities in the PKCalpha promoter region. Over-expression assay confirmed that the PKCalpha expression may be modulated by these two factors at the transcriptional level. Therefore, these results may provide a novel mechanism for PKCalpha expression regulation in human HCC cells.
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Affiliation(s)
- Yi-Hsien Hsieh
- Institute of Biochemistry and Biotechnology, College of Medicine, Chung Shan Medical University, Taichung 402, Taiwan
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31
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Seth A, Catzavelos C, Vary C, Ascione R. ETS transcription factors and targets in tumour invasion, angiogenesis and bone metastasis. ACTA ACUST UNITED AC 2005; 5:87-107. [PMID: 15992169 DOI: 10.1517/14728222.5.1.87] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The ETS gene family encodes unique transcription regulators that have a common ETS DNA binding domain. At least 25 distinct ETS related genes have been isolated from various species. The ETS family transcription factors are known to regulate genetic programs essential for differentiation and development processes and play diverse roles in a number of biological processes such as organogenesis and tissue remodelling during murine development, hematopoiesis, B-cell development, activation of T-cells and signal transduction, as well as osteogenesis, osteoblast differentiation and extracellular matrix mineralization. Based on the observation of overexpression of ETS related genes in various primary and metastatic tumors, their utility as potential therapeutic targets has been suggested. Antisense oligonucleotides, transdominant, and dominant-negative mutants have been exploited to target and inhibit ETS gene expression selectively. These ETS-targeted studies are being pursued to assess their antitumour effect, and hold the potential that such specific ETS-targeted inhibitors may become a viable option for cancer therapy. Collectively, these studies also demonstrate that Ets factors can regulate multiple aspects of the malignant phenotype of many tumor cells in particular neoangiogenesis and extracellular matrix-regulated (ECM-regulated) cell proliferation, motility and invasiveness.
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Affiliation(s)
- A Seth
- Department of Anatomic Pathology, Sunnybrook and Women's College Health Sciences Centre, University of Toronto, Ontario, Canada.
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32
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Vickers ER, Kasza A, Kurnaz IA, Seifert A, Zeef LAH, O'donnell A, Hayes A, Sharrocks AD. Ternary complex factor-serum response factor complex-regulated gene activity is required for cellular proliferation and inhibition of apoptotic cell death. Mol Cell Biol 2005; 24:10340-51. [PMID: 15542842 PMCID: PMC529045 DOI: 10.1128/mcb.24.23.10340-10351.2004] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Members of the ternary complex factor (TCF) subfamily of the ETS-domain transcription factors are activated through phosphorylation by mitogen-activated protein kinases (MAPKs) in response to a variety of mitogenic and stress stimuli. The TCFs bind and activate serum response elements (SREs) in the promoters of target genes in a ternary complex with a second transcription factor, serum response factor (SRF). The association of TCFs with SREs within immediate-early gene promoters is suggestive of a role for the ternary TCF-SRF complex in promoting cell cycle entry and proliferation in response to mitogenic signaling. Here we have investigated the downstream gene regulatory and phenotypic effects of inhibiting the activity of genes regulated by TCFs by expressing a dominantly acting repressive form of the TCF, Elk-1. Inhibition of ternary complex activity leads to the downregulation of several immediate-early genes. Furthermore, blocking TCF-mediated gene expression leads to growth arrest and triggers apoptosis. By using mutant Elk-1 alleles, we demonstrated that these effects are via an SRF-dependent mechanism. The antiapoptotic gene Mcl-1 is identified as a key target for the TCF-SRF complex in this system. Thus, our data confirm a role for TCF-SRF-regulated gene activity in regulating proliferation and provide further evidence to indicate a role in protecting cells from apoptotic cell death.
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Affiliation(s)
- Elaine R Vickers
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Rd., Manchester M13 9PT, United Kingdom
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33
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Fujioka S, Niu J, Schmidt C, Sclabas GM, Peng B, Uwagawa T, Li Z, Evans DB, Abbruzzese JL, Chiao PJ. NF-kappaB and AP-1 connection: mechanism of NF-kappaB-dependent regulation of AP-1 activity. Mol Cell Biol 2004; 24:7806-19. [PMID: 15314185 PMCID: PMC507000 DOI: 10.1128/mcb.24.17.7806-7819.2004] [Citation(s) in RCA: 319] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1) transcription factors regulate many important biological and pathological processes. Activation of NF-kappaB is regulated by the inducible phosphorylation of NF-kappaB inhibitor IkappaB by IkappaB kinase. In contrast, Fos, a key component of AP-1, is primarily transcriptionally regulated by serum responsive factors (SRFs) and ternary complex factors (TCFs). Despite these different regulatory mechanisms, there is an intriguing possibility that NF-kappaB and AP-1 may modulate each other, thus expanding the scope of these two rapidly inducible transcription factors. To determine whether NF-kappaB activity is involved in the regulation of fos expression in response to various stimuli, we analyzed activity of AP-1 and expression of fos, fosB, fra-1, fra-2, jun, junB, and junD, as well as AP-1 downstream target gene VEGF, using MDAPanc-28 and MDAPanc-28/IkappaBalphaM pancreatic tumor cells and wild-type, IKK1-/-, and IKK2-/- murine embryonic fibroblast cells. Our results show that elk-1, a member of TCFs, is one of the NF-kappaB downstream target genes. Inhibition of NF-kappaB activity greatly decreased expression of elk-1. Consequently, the reduced level of activated Elk-1 protein by extracellular signal-regulated kinase impeded constitutive, serum-, and superoxide-inducible c-fos expression. Thus, our study revealed a distinct and essential role of NF-kappaB in participating in the regulation of elk-1, c-fos, and VEGF expression.
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Affiliation(s)
- Shuichi Fujioka
- Department of Surgical Oncology, Box 107, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA
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34
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Firth JD, Putnins EE. Keratinocyte growth factor 1 inhibits wound edge epithelial cell apoptosis in vitro. J Invest Dermatol 2004; 122:222-31. [PMID: 14962112 DOI: 10.1046/j.0022-202x.2003.22124.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ability of keratinocyte growth factor 1 to modulate apoptosis in the absence of proliferation was studied in vitro. A HaCaT scrape wound model was developed in which dense monolayers prior to wounding were cultured to quiescence in defined media with hydroxyurea at concentrations that blocked proliferation without loss of cell viability. Scrape wounding was then found to induce apoptosis, originating at the wound edge, but subsequently radiating away over a 24 h period to encompass areas not originally damaged. Keratinocyte growth factor 1 inhibited this radial progression of apoptosis in a concentration-dependent manner up to 20 ng per mL with induced migration present at the wound edge. The extent of this rescue was modulated by the concentration of Ca2+ prior to wounding. In control wound cultures apoptotic bodies were found in cells adjacent to the wound interface but were greatly reduced in keratinocyte-growth-factor-1-treated groups. Keratinocyte growth factor 1 receptor expression was significantly induced within two to three cell widths of the scraped wound edge, at levels far exceeding those found at the leading edge of a nonwounded epithelial sheet. Tumor necrosis factor alpha (1-5 ng per mL) or Escherichia coli lipopolysaccharide (10-50 ng per mL) exacerbated scrape-induced early apoptosis (1-4 h), but was largely ameliorated by coculture with keratinocyte growth factor 1. Keratinocyte growth factor 1 protection was associated with a reduction in both caspase-3 activation and cytokeratin-19 loss. Protected wound edges were also associated with the maintenance of e-cadherin expression and induction of beta1 integrin and actin stress fiber organization. These results suggest that keratinocyte growth factor 1 may play a role in limiting mechanically induced apoptotic processes at the epithelial wound edge in a manner that is distinct from its proliferative function.
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Affiliation(s)
- James D Firth
- Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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35
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Galetic I, Maira SM, Andjelkovic M, Hemmings BA. Negative regulation of ERK and Elk by protein kinase B modulates c-Fos transcription. J Biol Chem 2003; 278:4416-23. [PMID: 12468535 DOI: 10.1074/jbc.m210578200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study, we have identified novel regulatory steps involved in the cross-talk between protein kinase B (PKB) and MAPK signaling pathways. We found that PKB down-regulates the Ras-Raf-MEK-ERK pathway by reducing the activity of ERK, which leads to inactivation of the transcription factor Elk1. In addition, PKB is able to reduce protein levels of Elk1. Both events lead to suppression of serum response element (SRE)-dependent transcription and a consequent decrease in the transcription of SRE-containing genes, such as c-fos. Because activation of the Ras/MAPK cascade is reported to increase c-fos transcription before apoptosis, our results are consistent with a specific role for PKB in promoting cell survival. Decrease in c-Fos protein levels in glioblastoma cells with constitutively active PKB provides further support for our observations. Therefore, our findings delineate a novel mechanism regulating immediate-early transcription, which may be involved in the initial steps in PKB-induced oncogenic transformation.
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Affiliation(s)
- Ivana Galetic
- Friedrich Miescher Institute, P. O. Box 2543, CH-4002 Basel, Switzerland
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36
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Abstract
The Ets family of transcription factors characterized by an evolutionarily-conserved DNA-binding domain regulates expression of a variety of viral and cellular genes by binding to a purine-rich GGAA/T core sequence in cooperation with other transcriptional factors and co-factors. Most Ets family proteins are nuclear targets for activation of Ras-MAP kinase signaling pathway and some of them affect proliferation of cells by regulating the immediate early response genes and other growth-related genes. Some of them also regulate apoptosis-related genes. Several Ets family proteins are preferentially expressed in specific cell lineages and are involved in their development and differentiation by increasing the enhancer or promoter activities of the genes encoding growth factor receptors and integrin families specific for the cell lineages. Many Ets family proteins also modulate gene expression through protein-protein interactions with other cellular partners. Deregulated expression or formation of chimeric fusion proteins of Ets family due to proviral insertion or chromosome translocation is associated with leukemias and specific types of solid tumors. Several Ets family proteins also participate in malignancy of tumor cells including invasion and metastasis by activating the transcription of several protease genes and angiogenesis-related genes.
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Affiliation(s)
- Tsuneyuki Oikawa
- Department of Cell Genetics, Sasaki Institute, 2-2 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan.
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37
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Chai Y, Chipitsyna G, Cui J, Liao B, Liu S, Aysola K, Yezdani M, Reddy ES, Rao VN. c-Fos oncogene regulator Elk-1 interacts with BRCA1 splice variants BRCA1a/1b and enhances BRCA1a/1b-mediated growth suppression in breast cancer cells. Oncogene 2001; 20:1357-67. [PMID: 11313879 DOI: 10.1038/sj.onc.1204256] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2000] [Revised: 01/05/2001] [Accepted: 01/09/2001] [Indexed: 01/19/2023]
Abstract
Elk-1, a c-Fos protooncogene regulator, which belongs to the ETS-domain family of transcriptional factors, plays an important role in the induction of immediate early gene expression in response to a variety of extracellular signals. In this study, we demonstrate for the first time the in vitro and in vivo interaction of Elk-1 with BRCA1 splice variants BRCA1a and BRCA1b using GST-pull down assays, co-imunoprecipitations/Western blot analysis of cell extracts from breast cancer cells and mammalian two-hybrid assays. We have localized the BRCA1 interaction domain of Elk-1 protein to the conserved ETS domain, a motif involved in DNA binding and protein-protein interactions. We also observed binding of BRCA1 proteins to other ETS-domain transcription factors SAP1, ETS-1, ERG-2 and Fli-1 but not to Elk-1 splice variant DeltaElk-1 and c-Fos protooncogene. Both BRCA1a and BRCA1b splice variants function as growth suppressors of human breast cancer cells. Interestingly, our studies reveal that although both Elk-1 and SAP-1 are highly homologous members of a subfamily of ETS domain proteins called ternary complex factors, it is only Elk-1 but not SAP-1 that can augment the growth suppressive function of BRCA1a/1b proteins in breast cancer cells. Thus Elk-1 could be a potential downstream target of BRCA1 in its growth control pathway. Furthermore, we have observed inhibition of c-Fos promoter activity in BRCA1a transfected stable breast cancer cells and over expression of BRCA1a/1b attenuates MEK-induced SRE activation in vivo. These results demonstrate for the first time a link between the growth suppressive function of BRCA1a/1b proteins and signal transduction pathway involving Elk-1 protein. All these results taken together suggest that one of the mechanisms by which BRCA1a/1b proteins function as growth/tumor suppressors is through inhibition of the expression of Elk-1 target genes like c-Fos.
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Affiliation(s)
- Y Chai
- Department of Medicine, Program of Cancer Genetics, Cancer Center, MCP Hahnemann University, 245 North 15th Street, New College Building, M.S. 481, Philadelphia, Pennsylvania 19102, USA
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Remy P, Baltzinger M. The Ets-transcription factor family in embryonic development: lessons from the amphibian and bird. Oncogene 2000; 19:6417-31. [PMID: 11175358 DOI: 10.1038/sj.onc.1204044] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This chapter reviews the expression and role of Ets-genes during embryogenesis of amphibians and birds. In addition to overlapping expression domains, some of them exhibit cell type-specific expression. Many of them are expressed in migratory cells: neural crest, endothelial, and pronephric duct cells for instance. They are also transcribed in embryonic areas affected by epithelio-mesenchymal transitions. Both processes involve modifications of cellular adhesion. Ets-family genes appear to coordinate changes in the expression of adhesion molecules and degradation of the extracellular matrix upon regulation of matrix metalloproteinases and their specific inhibitors. These functions are essential for physiological processes like tissue remodelling during embryogenesis or wound healing. Unfortunately they also play a harmful role in metastasis. Recent studies in the nervous system showed that Ets-genes contribute to the establishment of a cellular identity. This identity could rely on definite cell-surface determinants, among which cadherins could play an important role. In addition to cell-type specific expression, other factors contribute to the specificity of function of Ets-genes. These genes have a broad specificity of recognition of target sequences in gene promoters, insufficient for accurate control of gene expression. A fine tuning could arise from combinatorial interactions with other Ets- or accessory proteins.
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Affiliation(s)
- P Remy
- FRE 2168 du CNRS, IPCB, 21 rue René Descartes, 67084 Strasbourg cedex, France
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39
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Foos G, Hauser CA. Altered Ets transcription factor activity in prostate tumor cells inhibits anchorage-independent growth, survival, and invasiveness. Oncogene 2000; 19:5507-16. [PMID: 11114728 DOI: 10.1038/sj.onc.1203946] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The Ets family of transcription factors are important downstream targets in cellular transformation, as altering Ets activity has been found to reverse the transformed phenotype of Ras transformed mouse fibroblasts and of several human tumor cell lines. To determine whether Ets factors are important targets in the largely uncharacterized aberrant signaling in prostate cancer, we have altered Ets activity in the prostate tumor cell line PPC-1, by stable expression of either full-length Ets2, or a dominant inhibitor of Ets activity, the Ets2 DNA binding domain (Ets2DBD). Analysis of multiple independent clonal cell lines revealed that expression of either Ets2 or the Ets2DBD inhibited the anchorage-independent growth of PPC-1 cells up to 20-fold. In contrast to our previous findings with Ras-transformed NIH3T3 cells, PPC-1 cell lines expressing either Ets2 or the EtsDBD exhibited slower attached cell growth, increased Ets-dependent gene expression, and up to a 10-fold increase in apoptotic cell death. The p21cip gene was identified as a potential target of altered Ets signaling. Interestingly, the two distinct Ets2 constructs had strikingly different effects on in vitro invasiveness. Expression of the Ets2DBD almost completely blocked PPC-1 cell invasion through Matrigel, whereas over-expression of full-length Ets2 did not inhibit invasion. Overall, these results demonstrate that the balance of Ets factor activity can regulate multiple aspects of the transformed phenotype of PPC-1 prostate tumor cells, including anchorage-independent growth, survival, and invasiveness.
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Affiliation(s)
- G Foos
- La Jolla Cancer Research Center, The Burnham Institute, California 92037, USA
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