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Liu S, Medina-Perez P, Ha-Thi MC, Wieland A, Stecklum M, Hoffmann J, Tchernitsa O, Sers C, Schäfer R. Rapid testing of candidate oncogenes and tumour suppressor genes in signal transduction and neoplastic transformation. Adv Biol Regul 2021; 83:100841. [PMID: 34866037 DOI: 10.1016/j.jbior.2021.100841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/17/2021] [Accepted: 11/20/2021] [Indexed: 11/18/2022]
Abstract
The COSMIC database (version 94) lists 576 genes in the Cancer Gene Census which have a defined function as drivers of malignancy (oncogenes) or as tumour suppressors (Tier 1). In addition, there are 147 genes with similar functions, but which are less well characterised (Tier 2). Furthermore, next-generation sequencing projects in the context of precision oncology activities are constantly discovering new ones. Since cancer genes differ from their wild-type precursors in numerous molecular and biochemical properties and exert significant differential effects on downstream processes, simple assays that can uncover oncogenic or anti-oncogenic functionality are desirable and may precede more sophisticated analyses. We describe simple functional assays for PTPN11 (protein-tyrosine phosphatase, non-receptor-type 11)/SHP2 mutants, which are typically found in RASopathies and exhibit potential oncogenic activity. We have also designed a functional test for lysyl oxidase (LOX), a prototypical class II tumour suppressor gene whose loss of function may contribute to neoplastic transformation by RAS oncogenes. Moreover, we applied this test to analyse three co-regulated, RAS-responsive genes for transformation-suppressive activity. The integration of these tests into systems biology studies will contribute to a better understanding of cellular networks in cancer.
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Affiliation(s)
- Sha Liu
- Laboratory of Molecular Tumour Pathology and Cancer Systems Biology, Institute of Pathology, Charité Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany
| | - Paula Medina-Perez
- Laboratory of Molecular Tumour Pathology and Cancer Systems Biology, Institute of Pathology, Charité Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany
| | - Minh-Cam Ha-Thi
- Laboratory of Molecular Tumour Pathology and Cancer Systems Biology, Institute of Pathology, Charité Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany
| | - Anja Wieland
- Laboratory of Molecular Tumour Pathology and Cancer Systems Biology, Institute of Pathology, Charité Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany
| | - Maria Stecklum
- Experimental Pharmacology and Oncology GmbH, Robert-Rössle-Str. 10, D-13125, Berlin-Buch, Germany
| | - Jens Hoffmann
- Experimental Pharmacology and Oncology GmbH, Robert-Rössle-Str. 10, D-13125, Berlin-Buch, Germany
| | - Oleg Tchernitsa
- Laboratory of Molecular Tumour Pathology and Cancer Systems Biology, Institute of Pathology, Charité Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany
| | - Christine Sers
- Laboratory of Molecular Tumour Pathology and Cancer Systems Biology, Institute of Pathology, Charité Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany; German Cancer Consortium (DKTK), German Cancer Research Center, Im Neuenheimer Feld 280, D-69120, Heidelberg, Germany
| | - Reinhold Schäfer
- Laboratory of Molecular Tumour Pathology and Cancer Systems Biology, Institute of Pathology, Charité Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany; German Cancer Consortium (DKTK), German Cancer Research Center, Im Neuenheimer Feld 280, D-69120, Heidelberg, Germany; Charité Comprehensive Cancer Center Berlin, Germany.
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2
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Nareshkumar RN, Sulochana KN, Coral K. Inhibition of angiogenesis in endothelial cells by Human Lysyl oxidase propeptide. Sci Rep 2018; 8:10426. [PMID: 29993014 PMCID: PMC6041307 DOI: 10.1038/s41598-018-28745-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 06/05/2018] [Indexed: 12/14/2022] Open
Abstract
Angiogenesis is a critical process involved in normal physiology. Pathological angiogenesis is observed in vascular diseases and neoplasia. The propeptide domain of LOX (LOX-PP) has been shown to inhibit tumorigenesis in various cancers. In this study, we explored the role of both overexpressed and recombinant LOX-PP in naïve human umbilical vein endothelial cell with the addition of vascular endothelial growth factor (VEGF). Primarily, we observed a significant reduction in the angiogenesis signaling pathways upon LOX-PP overexpression by proteomic analysis. Further functional analysis showed that the VEGF induced cell proliferation, migration, adhesion and tube formation was inhibited by LOX-PP. Moreover, LOX-PP arrested cells at S-phase, reduced F-actin levels and decreased phosphorylation of focal adhesion kinase (FAK) and extracellular signal regulated kinase (ERK). The anti-angiogenic effect of LOX-PP was further confirmed by the reduction in the vascular network formation in chick chorioallantoic membrane (CAM). These results indicate that inhibition of angiogenesis events is not only achieved by overexpressing LOX-PP but also by addition of rLOX-PP. Taken together our findings discovered the anti-angiogenic role of LOX-PP in endothelial cells which suggests that harnessing this potential can be a promising strategy to inhibit angiogenesis.
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Affiliation(s)
- Ragavachetty Nagaraj Nareshkumar
- R.S. Mehta Jain Department of Biochemistry and Cell Biology, Vision Research Foundation, 41, College road, Chennai, India.,School of Chemical and Biotechnology, SASTRA University, Thanjavur, India
| | | | - Karunakaran Coral
- R.S. Mehta Jain Department of Biochemistry and Cell Biology, Vision Research Foundation, 41, College road, Chennai, India.
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3
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Liu Y, Lv B, He Z, Zhou Y, Han C, Shi G, Gao R, Wang C, Yang L, Song H, Yuan W. Lysyl oxidase polymorphisms and susceptibility to osteosarcoma. PLoS One 2012; 7:e41610. [PMID: 22911823 PMCID: PMC3402457 DOI: 10.1371/journal.pone.0041610] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 06/22/2012] [Indexed: 12/24/2022] Open
Abstract
Despite the knowledge of many genetic alterations present in osteosarcoma, the complexity of this disease precludes placing its biology into a simple conceptual framework. Lysyl oxidase (LOX) catalyzes the cross-linking of elastin and collagen, which is essential for the structural integrity and function of bone tissue. In the current study, we performed genomic sequencing on all seven exons--including the intron-exon splice sites, and the putative promoter region of LOX gene--followed by luciferase reporter assay to analyze the function of newly identified polymorphisms. Associations between LOX polymorphisms and osteosarcoma were then evaluated. Our sequencing data revealed three polymorphisms (-22G/C, 225C/G, and 473G/A) in the exons and promoter region of LOX. The -22G/C polymorphism lies in the downstream core promoter element (DPE) region and caused a decrease in promoter activity of LOX. The prevalence of the -22C allele and 473A allele were significantly increased in osteosarcoma patients compared to controls (odds ratio [OR] = 3.88, 95% confidence interval [CI]= 1.94-7.78, p = 4.18×10(-5), and OR = 1.38, 95%CI = 1.07-1.78, p = 0.013; p 0.0167 was considered significant after Bonferroni correction). Analyzing haplotype showed that the frequency of CCG haplotype (-22, 225, 473) was significantly higher in osteosarcoma cases than in healthy controls after Bonferroni correction (p = 4.46×10(-4)). These results indicate that the -22G/C polymorphism may affect the expression of LOX, and that -22G/C and 473G/A polymorphisms may be new risk factors for osteosarcoma. These findings reveal a potential new pathway by which genetic polymorphisms may affect human diseases.
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Affiliation(s)
- Yang Liu
- Department of Spine Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Bitao Lv
- Department of Spine Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Zhimin He
- Department of Orthopedic Surgery, Fengxian Branch of the Shanghai No.6 People’s Hospital, Shanghai, China
| | - Yujia Zhou
- School of Occupational Therapy, Western University, London, Ontario, Canada
| | - Carrie Han
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Guodong Shi
- Department of Spine Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Rui Gao
- Department of Spine Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Ce Wang
- Department of Spine Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Lili Yang
- Department of Spine Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Haihan Song
- Emergency Center, Shanghai East Hospital, Tongji University, Shanghai, China
| | - Wen Yuan
- Department of Spine Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China
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Oleggini R, Di Donato A. Lysyl oxidase regulates MMTV promoter: indirect evidence of histone H1 involvement. Biochem Cell Biol 2011; 89:522-32. [DOI: 10.1139/o11-049] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lysyl oxidase (LOX) is the enzyme that facilitates the cross-linking of collagen and elastin, although other functions for this enzyme have been indicated. Of these other functions, we describe herein the ability of LOX to regulate several gene promoters, like collagen III, elastin, and cyclin D1. We have previously demonstrated a specific binding between LOX and histone H1, in vitro. Therefore, we investigated whether LOX would affect the mouse mammary tumor virus (MMTV) promoter and its glucocorticoid regulation, which depends on the phophorylation status of histone H1. Our results show that the over-expression of recombinant human LOX was able to trigger MMTV activity, both in the presence and absence of glucocorticoids. Moreover, we demonstrated that histone H1 from cells expressing recombinant LOX contained isodesmosine and desmosine, indicating specific lysyl-oxidase-dependent lysine modifications. Finally, we were able to co-immunoprecipitate the exogenous LOX and histone H1 from the LOX transfected cells. The data are compatible with a decreased positive charge of histone H1, owing to deamination by LOX of its lysine residues. This event would favor H1 detachment from the target DNA, and consequent opening of the MMTV promoter structure to the activating transcription factors. The presented data, therefore, suggest a possible histone-H1-dependent mechanism for the modulation of MMTV promoter by LOX.
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The lysyl oxidase propeptide interacts with the receptor-type protein tyrosine phosphatase kappa and inhibits β-catenin transcriptional activity in lung cancer cells. Mol Cell Biol 2011; 31:3286-97. [PMID: 21690299 DOI: 10.1128/mcb.01426-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The propeptide region of the lysyl oxidase proenzyme (LOX-PP) has been shown to inhibit Ras signaling in NIH 3T3 and lung cancer cells with activated RAS, but its mechanism of action is poorly understood. Here, a yeast two-hybrid assay of LOX-PP-interacting proteins identified a clone encoding the intracellular phosphatase domains of receptor-type protein tyrosine phosphatase kappa (RPTP-κ), and the interaction of the two proteins in mammalian cells was confirmed. RPTP-κ is proteolytically processed to isoforms that have opposing effects on β-catenin activity. The RPTP-κ transmembrane P subunit interacts with and sequesters β-catenin at the cell membrane, where it can associate with E-cadherin and promote intercellular interactions. At high cell density, further processing of the P subunit yields a phosphatase intracellular portion (PIC) subunit, which chaperones β-catenin to the nucleus, where it can function to activate transcription. Lung cancer cells were found to contain higher PIC levels than untransformed lung epithelial cells. In H1299 lung cancer cells, ectopic LOX-PP expression reduced the nuclear levels of PIC by increasing its turnover in the lysosome, thereby decreasing the nuclear levels and transcriptional activity of β-catenin while increasing β-catenin membrane localization. Thus, LOX-PP is shown to negatively regulate pro-oncogenic β-catenin signaling in lung cancer cells.
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6
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Lysyl oxidase: a potential target for cancer therapy. Inflammopharmacology 2010; 19:117-29. [DOI: 10.1007/s10787-010-0073-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 11/02/2010] [Indexed: 12/20/2022]
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7
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Noda M, Takahashi C, Matsuzaki T, Kitayama H. What we learn from transformation suppressor genes: lessons from RECK. Future Oncol 2010; 6:1105-16. [DOI: 10.2217/fon.10.80] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Expression cloning is a powerful approach to finding genes that induce appreciable changes in cultured cells. One way to use this technique in cancer research is to isolate cDNAs that induce flat reversion in transformed cells. Such screening, however, is inherently artificial, and therefore requires independent validation of the clinical relevance of isolated genes. Studies of the mechanisms of actions, physiological functions and mechanisms of regulation of these genes at various levels may enrich our knowledge of cancer biology and supplement our toolbox in developing new cancer diagnoses and therapies. In this article we discuss the promise, limitations and recent innovations in this approach, taking one transformation suppressor gene, RECK, as an example.
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Affiliation(s)
| | - Chiaki Takahashi
- Division of Oncology & Molecular Biology, Center for Cancer & Stem Cell Research, Cancer Research Institute, Kanazawa University, Kakuma-cho, Kanazawa 920-1192, Japan
| | - Tomoko Matsuzaki
- Department of Molecular Oncology & Global COE Program, Kyoto University Graduate School of Medicine, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hitoshi Kitayama
- Department of Molecular Oncology & Global COE Program, Kyoto University Graduate School of Medicine, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
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Albinger-Hegyi A, Stoeckli SJ, Schmid S, Storz M, Iotzova G, Probst-Hensch NM, Rehrauer H, Tinguely M, Moch H, Hegyi I. Lysyl oxidase expression is an independent marker of prognosis and a predictor of lymph node metastasis in oral and oropharyngeal squamous cell carcinoma (OSCC). Int J Cancer 2010; 126:2653-62. [PMID: 19816945 DOI: 10.1002/ijc.24948] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Proteins of the lysyl oxidase (LOX) family are important modulators of the extracellular matrix. However, they have an important role in the tumour development as well as in tumour progression. To evaluate the diagnostic and prognostic value of the LOX protein in oral and oropharyngeal squamous cell carcinoma (OSCC) we performed QRT-PCR and immunohistochemical analysis on two tissue microarrays (622 tissue samples in total). Significantly higher LOX expression was detected in high grade dysplastic oral mucosa as well as in OSCC when compared to normal oral mucosa (P < 0.001). High LOX expression was correlated with clinical TNM stage (P = 0.020), lymph node metastases for the entire cohort (P < 0.001), as well as in the subgroup of small primary tumours (T1/T2, P < 0.001). Moreover, high LOX expression was correlated with poor overall survival (P = 0.004) and disease specific survival (P = 0.037). In a multivariate analysis, high LOX expression was an independent prognostic factor, predicting unfavourable overall survival. In summary, LOX expression is an independent prognostic biomarker and a predictor of lymph node metastasis in OSCC. Moreover, LOX overexpression may be an early phenomenon in the pathogenesis of OSCC and thus an attractive novel target for chemopreventive and therapeutic strategies.
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Affiliation(s)
- Andrea Albinger-Hegyi
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, Zurich, Switzerland
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9
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Lysyl oxidase propeptide inhibits prostate cancer cell growth by mechanisms that target FGF-2-cell binding and signaling. Oncogene 2009; 28:3390-400. [PMID: 19597471 PMCID: PMC2753565 DOI: 10.1038/onc.2009.203] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Enhanced RAS signaling and decreased androgen dependence of prostate cancer cells accompany poor clinical outcomes. Elevated autocrine FGF-2 signaling promotes prostate cancer cell growth and survival. Expression of lysyl oxidase (LOX) inhibits RAS transforming activity. LOX is secreted as 50 kDa pro-lysyl oxidase protein and then undergoes extracellular proteolytic processing to form ~30 kDa lysyl oxidase enzyme and ~18 kDa pro-peptide (LOX-PP). We have previously shown that LOX-PP inhibits breast cancer cell transformation and tumor formation, but mechanisms of action of LOX-PP have not been fully elucidated. Here we report that LOX expression is reduced in prostate cancer cell lines and that recombinant LOX-PP protein inhibits serum-stimulated DNA synthesis and MEK/ERK and PI3K/AKT pathways in DU 145 and PC-3 androgen-independent cell lines. In DU 145 cells, treatment with a pharmacologic FGF-receptor inhibitor or a neutralizing anti-FGFR1 antibody mimicked LOX-PP inhibition of serum-stimulated DNA synthesis. FGF-2-stimulated DNA synthesis, ERK1/2, AKT, and FRS2α activation were found all to be inhibited by LOX-PP in DU 145 cells. LOX-PP reduced specific binding of FGF-2 to DU 145 cells, suggesting that LOX-PP targets FGF signaling at the receptor. Interestingly, PC-3 cells did not respond to FGF-2, consistent with previous reports. We conclude that LOX-PP inhibits proliferation of DU 145 cells by interfering with FGFR(s) binding and signaling, and that LOX-PP has other mechanisms of action in PC-3 cells.
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Lysyl oxidase (LOX) mRNA expression and genes of the differentiated osteoblastic phenotype are upregulated in human osteosarcoma cells by suramin. Cancer Lett 2008; 265:45-54. [PMID: 18374478 DOI: 10.1016/j.canlet.2008.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Revised: 01/31/2008] [Accepted: 02/03/2008] [Indexed: 12/12/2022]
Abstract
It is well known that suramin influences proliferation and differentiation of tumour cells. To study whether and how suramin effects osteosarcoma (OS) cells, proliferation, differentiation, LOX mRNA expression and telomerase activity (TA) was analysed in the human MG-63 and U-2 OS, and the rat UMR-106 OS cell lines. Data show that suramin inhibited proliferation in the human cell lines and upregulated alkaline phosphatase activity. TA was attenuated in the human cells while in UMR-106 it was not changed. In UMR-106 suramin had no influence on osteocalcin and LOX expression, in the human cells however, both genes were upregulated.
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Ou CC, Hsu SC, Hsieh YH, Tsou WL, Chuang TC, Liu JY, Kao MC. Downregulation of HER2 by RIG1 involves the PI3K/Akt pathway in ovarian cancer cells. Carcinogenesis 2008; 29:299-306. [PMID: 18174256 DOI: 10.1093/carcin/bgm263] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Interferon-gamma (IFN-gamma) is known to downregulate HER2 oncoprotein (p185(HER2) or briefly p185) in prostate cancer cells. We demonstrate that the IFN-gamma-induced retinoid-inducible gene 1 (RIG1) acts as a transrepressor of p185. Furthermore, we exhibit that RIG1 downregulates the activated (phosphorylated) form of p185 and phosphoinositide-3 kinase (PI3K)/serine/threonine-specific protein kinase (Akt) and the mammalian target of rapamycin (mTOR), downstream substrates of HER2. We also elucidate that heregulin (HRG) specifically restores the activation of p185 and Akt after their activities are reduced by RIG1. Additionally, expression of vascular endothelial growth factor (VEGF) increases through the HER2- and Akt/mTOR-signaling pathways, indicating that VEGF is downregulated by RIG1 within the cell. These findings suggest that RIG1 plays a role in IFN-gamma-mediated therapy by downregulating p185 and its downstream PI3K/Akt/mTOR/VEGF-signaling pathway. These results may provide a new therapeutic mechanism for the clinical use of IFN-gamma and RIG1.
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Affiliation(s)
- Chien-Chih Ou
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan 114, Republic of China
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12
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Wu G, Guo Z, Chang X, Kim MS, Nagpal JK, Liu J, Maki JM, Kivirikko KI, Ethier SP, Trink B, Sidransky D. LOXL1 and LOXL4 are epigenetically silenced and can inhibit ras/extracellular signal-regulated kinase signaling pathway in human bladder cancer. Cancer Res 2007; 67:4123-9. [PMID: 17456585 DOI: 10.1158/0008-5472.can-07-0012] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Promoter hypermethylation is one of the common mechanisms leading to gene silencing in various human cancers. Using a combination of pharmacologic unmasking and microarray techniques, we identified 59 candidate hypermethylated genes, including LOXL1, a lysyl oxidase-like gene, in human bladder cancer cells. We further showed that LOXL1 and LOXL4 are commonly silenced genes in human bladder cancer cells, and this silence is predominantly related to promoter methylation. We also found LOXL1 and LOXL4 gene methylation and loss of expression in primary bladder tumors. In addition, somatic mutations were identified in LOXL4, but not in LOXL1 in bladder cancer. Moreover, reintroduction of LOXL1 and LOXL4 genes into human bladder cancer cells leads to a decrease of colony formation ability. Further studies indicated that the overexpression of LOXL1 and LOXL4 could antagonize Ras in activating the extracellular signal-regulated kinase (ERK) signaling pathway. Thus, our current study suggests for the first time that lysyl oxidase-like genes can act as tumor suppressor genes and exert their functions through the inhibition of the Ras/ERK signaling pathway in human bladder cancer.
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Affiliation(s)
- Guojun Wu
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA.
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Min C, Kirsch KH, Zhao Y, Jeay S, Palamakumbura AH, Trackman PC, Sonenshein GE. The Tumor Suppressor Activity of the Lysyl Oxidase Propeptide Reverses the Invasive Phenotype of Her-2/neu–Driven Breast Cancer. Cancer Res 2007; 67:1105-12. [PMID: 17283144 DOI: 10.1158/0008-5472.can-06-3867] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Expression of the lysyl oxidase gene (LOX) was found to inhibit the transforming activity of the ras oncogene in NIH 3T3 fibroblasts and was hence named the ras recision gene (rrg). Lysyl oxidase (LOX) is synthesized and secreted as a 50-kDa inactive proenzyme (Pro-LOX), which is processed by proteolytic cleavage to a functional 32-kDa enzyme and an 18-kDa propeptide (LOX-PP). Recently, the ras recision activity of the LOX gene in NIH 3T3 cells was mapped to its propeptide region. Here, we show for the first time that LOX-PP inhibits transformation of breast cancer cells driven by Her-2/neu, an upstream activator of Ras. LOX-PP expression in Her-2/neu-driven breast cancer cells in culture suppressed Akt, extracellular signal-regulated kinase, and nuclear factor-kappaB activation. Her-2/neu-induced epithelial to mesenchymal transition was reverted by LOX-PP, as judged by reduced levels of Snail and vimentin; up-regulation of E-cadherin, gamma-catenin, and estrogen receptor alpha; and decreased ability to migrate or to form branching colonies in Matrigel. Furthermore, LOX-PP inhibited Her-2/neu tumor formation in a nude mouse xenograft model. Thus, LOX-PP inhibits signaling cascades induced by Her-2/neu that promote a more invasive phenotype and may provide a novel avenue for treatment of Her-2/neu-driven breast carcinomas.
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Affiliation(s)
- Chengyin Min
- Department of Biochemistry, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA
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Luo F, Hamoudi R, Brooks DG, Patek CE, Arends MJ. Stem cell gene expression changes induced specifically by mutated K-ras. Gene Expr 2007; 14:101-15. [PMID: 18257393 PMCID: PMC6042043 DOI: 10.3727/105221607783417583] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
K-Ras proteins transduce signals from membrane-bound receptors via multiple downstream effector pathways and thereby regulate fundamental stem cell processes that affect neoplasia, including proliferation, apoptosis, and differentiation, but their contribution to tumourigenesis is unclear. Because cancers develop from stem cells, we set out to determine the characteristic changes in gene expression brought about by mutated K-ras (without interference from normal K-ras) in otherwise normal stem cells. cDNA microarrays were used to analyze gene expression profiles comparing wild-type murine embryonic stem (ES) cells with K-ras(Val12) expressing ES cells (previously made null for both endogenous K-ras alleles and transfected with K-ras(Val12), with valine for glycine at codon 12). K-ras(Val12) was expressed at 1.2-fold normal K-ras levels and produced transcripts for both activated K-Ras4A and 4B isoforms. The array expression data were confirmed by real-time quantitative PCR analysis of selected genes expressed both in the K-ras(Val12) expressing ES cells (R = 0.91 with array data) and in the normal intestinal tissues of K-ras(Val12) transgenic mice (R = 0.91 with array data). Changes in gene expression were correlated with the effects of K-ras(Val12) expression on ES cells of enhancing self-renewal in an undifferentiated state, increasing susceptibility to DNA damage-induced apoptosis, and increased proliferation. These expression data may explain, at least in part, some neoplasia-related aspects of the phenotypic changes brought about in this ES cell line by mutated K-ras, in that upregulation of cell growth-related proteins and DNA-associated proteins is consistent with increased proliferation; upregulation of certain apoptosis-related proteins is consistent with a greater susceptibility to DNA damage-induced apoptosis; and downregulation of structural proteins, extracellular matrix components, secretory proteins and receptors is consistent with a less differentiated phenotype.
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Affiliation(s)
- Feijun Luo
- *Department of Pathology, Addenbrooke’s Hospital, Hills Road, University of Cambridge, Cambridge, CB2 2QQ, UK
| | - Rifat Hamoudi
- *Department of Pathology, Addenbrooke’s Hospital, Hills Road, University of Cambridge, Cambridge, CB2 2QQ, UK
| | - David G. Brooks
- *Department of Pathology, Addenbrooke’s Hospital, Hills Road, University of Cambridge, Cambridge, CB2 2QQ, UK
| | - Charles E. Patek
- †Sir Alastair Currie Cancer Research UK Laboratories, Molecular Medicine Centre, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Mark J. Arends
- *Department of Pathology, Addenbrooke’s Hospital, Hills Road, University of Cambridge, Cambridge, CB2 2QQ, UK
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Giampuzzi M, Oleggini R, Albanese C, Pestell R, Di Donato A. beta-catenin signaling and regulation of cyclin D1 promoter in NRK-49F cells transformed by down-regulation of the tumor suppressor lysyl oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1745:370-81. [PMID: 15946752 DOI: 10.1016/j.bbamcr.2005.04.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 04/28/2005] [Accepted: 04/29/2005] [Indexed: 11/28/2022]
Abstract
Lysyl oxidase is the enzyme that is essential for collagen and elastin cross-linking. Previous investigations showed that lysyl oxidase is down-regulated in many human tumors and ras-transformed cells. Recently, we proved that antisense down-regulation of lysyl oxidase in NRK-49F cells induced phenotypic changes and oncogenic transformation, characterized by p21(ras) activation and beta-catenin/cyclin D1 up-regulation. In the present paper, we examined beta-catenin intracellular distribution and its association with E-cadherin. We observed an increased association between E-cadherin and beta-catenin in the lysyl-oxidase down-regulated cells during serum starvation. Moreover, we found that beta-catenin cytoplasmic and nuclear levels were increased, suggesting a failure of its down-regulation by the APC-GSK-3beta system, in particular the GSK-3beta phosphorylation of ser-33/37 and thr-41 of beta-catenin. Finally, we investigated the mechanisms leading to the observed cyclin D1 up-regulation. We showed that in the antisense lysyl oxidase cells the cyclin D1 promoter was activated through the LEF and the ATF/CRE sites in the proximal promoter. While the promoter activation through LEF is compatible with beta-catenin signaling, we investigated the possibility that the CRE-dependent activation might be linked to the down-regulation of lysyl oxidase. In fact, up-regulation of lysyl oxidase in a COS-7 cell model showed a significant diminution of the CREB protein binding to the cyclin D1 promoter, leading to a dramatic inhibition of its activity and a significant down-regulation of cyclin D1 protein level in vivo. Finally, our study describes some major anomalies occurring in lysyl oxidase down-regulated fibroblasts, related to beta-catenin signaling and cyclin D1 expression.
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Affiliation(s)
- Monia Giampuzzi
- Laboratorio di Nefrologia, Istituto G. Gaslini, Largo G. Gaslini, 5, 16147 Genova, Italy
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16
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Affiliation(s)
- R Schäfer
- Department of Pathology, University of Zurich, Switzerland
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17
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Wang HP, Hwang TL, Lee O, Tseng YJ, Shu CY, Lee SJ. Selective cytotoxicity of azatyrosinamides against ras-transformed NIH 3T3 cells. Bioorg Med Chem Lett 2005; 15:4272-4. [PMID: 16039850 DOI: 10.1016/j.bmcl.2005.06.048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Revised: 06/21/2005] [Accepted: 06/21/2005] [Indexed: 11/30/2022]
Abstract
This study aims to develop novel azatyrosinamide compounds structurally modified from ras-specific antioncogenic azatyrosine. Analogues 4-15 were prepared and their inhibition on the growth of wild-type and ras-transformed NIH 3T3 cell lines was compared. Compound 12 was found to be the most active with IC50 16.5+/-2.2 microM which is 458-fold more potent than that of azatyrosine. The selective toxicity, defined as IC(50 wild-type)/IC(50 ras-transformed) for this compound was 138.5.
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Affiliation(s)
- H P Wang
- Graduate Institute of Natural Products, Chang Gung University College of Medicine, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan 333, Taiwan.
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18
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Peinado H, del Carmen Iglesias-de la Cruz M, Olmeda D, Csiszar K, Fong KSK, Vega S, Nieto MA, Cano A, Portillo F. A molecular role for lysyl oxidase-like 2 enzyme in snail regulation and tumor progression. EMBO J 2005; 24:3446-58. [PMID: 16096638 PMCID: PMC1276164 DOI: 10.1038/sj.emboj.7600781] [Citation(s) in RCA: 341] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Accepted: 07/20/2005] [Indexed: 11/09/2022] Open
Abstract
The transcription factor Snail controls epithelial-mesenchymal transitions (EMT) by repressing E-cadherin expression and other epithelial genes. However, the mechanisms involved in the regulation of Snail function are not fully understood. Here we show that lysyl-oxidase-like 2 and 3 (LOXL2 and LOXL3), two members of the lysyl-oxidase gene family, interact and cooperate with Snail to downregulate E-cadherin expression. Snail's lysine residues 98 and 137 are essential for Snail stability, functional cooperation with LOXL2/3 and induction of EMT. Overexpression of LOXL2 or LOXL3 in epithelial cells induces an EMT process, supporting their implication in tumor progression. The biological importance of LOXL2 is further supported by RNA interference of LOXL2 in Snail-expressing metastatic carcinoma cells, which led to a strong decrease of tumor growth associated to increased apoptosis and reduced expression of mesenchymal and invasive/angiogenic markers. Taken together, these results establish a direct link between LOXL2 and Snail in carcinoma progression.
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Affiliation(s)
- Héctor Peinado
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas ‘Alberto Sols', Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Arturo Duperier, Madrid, Spain
| | - Maria del Carmen Iglesias-de la Cruz
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas ‘Alberto Sols', Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Arturo Duperier, Madrid, Spain
| | - David Olmeda
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas ‘Alberto Sols', Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Arturo Duperier, Madrid, Spain
| | - Katalin Csiszar
- Cardiovascular Research Center, John A Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - Keith S K Fong
- Cardiovascular Research Center, John A Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - Sonia Vega
- Instituto Cajal, Avenida Doctor Arce, Madrid, Spain
| | | | - Amparo Cano
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas ‘Alberto Sols', Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Arturo Duperier, Madrid, Spain
- Instituto de Investigaciones Biomédicas ‘Alberto Sols', CSIC-UAM, Arturo Duperier 4, 28029 Madrid, Spain. Tel.: +34 91 585 4411; Fax: +34 91 585 4401; E-mail:
| | - Francisco Portillo
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas ‘Alberto Sols', Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Arturo Duperier, Madrid, Spain
- Instituto de Investigaciones Biomédicas ‘Alberto Sols', CSIC-UAM, Arturo Duperier 4, 28029 Madrid, Spain. Tel.: +34 91 585 4457; Fax: +34 91 585 4401; E-mail:
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19
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Jiang SY, Wu MS, Chen LM, Hung MW, Lin HE, Chang GG, Chang TC. Identification and characterization of the retinoic acid response elements in the human RIG1 gene promoter. Biochem Biophys Res Commun 2005; 331:630-9. [PMID: 15850806 DOI: 10.1016/j.bbrc.2005.03.214] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Indexed: 12/11/2022]
Abstract
The expression of retinoic acid-induced gene 1 (RIG1), a class II tumor suppressor gene, is induced in cells treated with retinoids. RIG1 has been shown to express ubiquitously and the increased expression of this gene appears to suppress cell proliferation. Recent studies also demonstrated that this gene may play an important role in cell differentiation and the progression of cancer. In spite of the remarkable regulatory role of this protein, the molecular mechanism of RIG1 expression induced by retinoids remains to be clarified. The present study was designed to study the molecular mechanism underlying the all-trans retinoic acid (atRA)-mediated induction of RIG1 gene expression. Polymerase chain reaction was used to generate a total of 10 luciferase constructs that contain various fragments of the RIG1 5'-genomic region. These constructs were then transfected into human gastric cancer SC-M1 and breast cancer T47D cells for transactivation analysis. atRA exhibited a significant induction in luciferase activity only through the -4910/-5509 fragment of the 5'-genomic region of RIG1 gene relative to the translation initiation site. Further analysis of this promoter fragment indicated that the primary atRA response region is located in between -5048 and -5403 of the RIG1 gene. Within this region, a direct repeat sequence with five nucleotide spacing, 5'-TGACCTctattTGCCCT-3' (DR5, -5243/-5259), and an inverted repeat sequence with six nucleotide spacing, 5'-AGGCCAtggtaaTGGCCT-3' (IR6, -5323/-5340), were identified. Deletion and mutation of the DR5, but not the IR6 element, abolished the atRA-mediated activity. Electrophoretic mobility shift assays with nuclear extract from atRA-treated cells indicated the binding of retinoic acid receptor (RAR) and retinoid X receptor (RXR) heterodimers specifically to this response element. In addition to the functional DR5, the region contains many other potential sequence elements that are required to maximize the atRA-mediated induction. Taken together, we have identified and characterized the functional atRA response element that is responsible for the atRA-mediated induction of RIG1 gene.
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Affiliation(s)
- Shun-Yuan Jiang
- Department of Microbiology and Immunology, National Defense Medical Center, Taipei, Taiwan, ROC
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20
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Molnar J, Ujfaludi Z, Fong SFT, Bollinger JA, Waro G, Fogelgren B, Dooley DM, Mink M, Csiszar K. Drosophila lysyl oxidases Dmloxl-1 and Dmloxl-2 are differentially expressed and the active DmLOXL-1 influences gene expression and development. J Biol Chem 2005; 280:22977-85. [PMID: 15811848 DOI: 10.1074/jbc.m503006200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian lysyl oxidase (LOX) is essential for the catalysis of lysyl-derived cross-links in fibrillar collagens and elastin in the extracellular matrix and has also been implicated in cell motility, differentiation, and tumor cell invasion. The active LOX has been shown to translocate to the nuclei of smooth muscle cells and regulate chromatin structure and transcription. It is difficult to interpret the role of the LOX protein as it is co-expressed with other members of the LOX amine oxidase family in most mammalian cells. To investigate the function of the LOX proteins, we have characterized the Drosophila lysyl oxidases Dmloxl-1 and Dmloxl-2. We present the gene, domain structure, and expression pattern of Dmloxl-1 and Dmloxl-2 during development. In early development, only Dmloxl-1 was expressed, which allowed functional studies. We have expressed Dmloxl-1 in S2 cells and determined that it is a catalytically active enzyme, inhibited by beta-amino-proprionitrile (BAPN), a specific LOX inhibitor. We localized DmLOXL-1 in the nuclei in embryos and in adult salivary gland cells in the nuclei, cytoplasm, and cell surface, using immunostaining and a DmLOXL-1 antibody. To address the biological function of Dmloxl-1, we raised larvae under BAPN inhibitory conditions and over-expressed Dmloxl-1 in transgenic Drosophila. DmLOXL-1 inhibition resulted in developmental delay and a shift in sex ratio; over-expression in the w(m4) variegating strain increased drosopterin production, demonstrating euchromatinization. Our previous data on the transcriptional down-regulation of seven ribosomal genes and the glue gene under inhibitory conditions and the current results collectively support a nuclear role for Dmloxl-1 in euchromatinization and gene regulation.
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MESH Headings
- Active Transport, Cell Nucleus
- Amino Acid Sequence
- Aminopropionitrile/pharmacology
- Animals
- Animals, Genetically Modified
- Blotting, Northern
- Catalysis
- Cell Differentiation
- Cell Line
- Cell Membrane/metabolism
- Cell Movement
- Cell Nucleus/metabolism
- Chromatin/chemistry
- Chromatin/metabolism
- Chromosome Mapping
- Collagen/chemistry
- Cytoplasm/metabolism
- DNA Primers/chemistry
- DNA, Complementary/metabolism
- Down-Regulation
- Drosophila melanogaster
- Elastin/chemistry
- Euchromatin/metabolism
- Extracellular Matrix/metabolism
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Enzymologic
- Genome
- Immunohistochemistry
- Microscopy, Confocal
- Models, Genetic
- Molecular Sequence Data
- Muscle, Smooth/cytology
- Polymerase Chain Reaction
- Protein Structure, Tertiary
- Protein-Lysine 6-Oxidase/biosynthesis
- Protein-Lysine 6-Oxidase/chemistry
- RNA, Messenger/metabolism
- Recombinant Proteins/chemistry
- Saliva/metabolism
- Salivary Glands/metabolism
- Sequence Homology, Amino Acid
- Transcription, Genetic
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Affiliation(s)
- Janos Molnar
- Cardiovascular Research Center, John A. Burns School of Medicine, University of Hawaii, Honolulu, 96822, USA
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21
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Kaneda A, Wakazono K, Tsukamoto T, Watanabe N, Yagi Y, Tatematsu M, Kaminishi M, Sugimura T, Ushijima T. Lysyl oxidase is a tumor suppressor gene inactivated by methylation and loss of heterozygosity in human gastric cancers. Cancer Res 2004; 64:6410-5. [PMID: 15374948 DOI: 10.1158/0008-5472.can-04-1543] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Lysyl oxidase (LOX) and HRAS-like suppressor (HRASLS) are silenced in human gastric cancers and are reported to have growth-suppressive activities in ras-transformed mouse/rat fibroblasts. Here, we analyzed whether or not LOX and HRASLS are tumor suppressor genes in human gastric cancers. Loss of heterozygosity and promoter methylation of LOX were detected in 33% (9 of 27) and 27% (26 of 96) of gastric cancers, respectively. Biallelic methylation and loss of heterozygosity with promoter methylation were also demonstrated in gastric cancers. Silencing of LOX was also observed in colon, lung, and ovarian cancer cell lines. As for mutations, only one possible somatic mutation was found by analysis of 96 gastric cancer samples and 58 gastric and other cancer cell lines. When LOX was introduced into a gastric cancer cell line, MKN28, in which LOX and HRASLS were silenced, it reduced the number of anchorage-dependent colonies to 57 to 61%, and the number of anchorage-independent colonies to 11 to 23%. Sizes of tumors formed in nude mice were reduced to 19 to 26%. Growth suppression in soft agar assay was also observed in another gastric cancer cell line, KATOIII. On the other hand, neither loss of heterozygosity nor a somatic mutation was detected in HRASLS, and its introduction into MKN28 did not suppress the growth in vitro or in vivo. These data showed that LOX is a tumor suppressor gene inactivated by methylation and loss of heterozygosity in gastric cancers, and possibly also in other cancers.
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Affiliation(s)
- Atsushi Kaneda
- Carcinogenesis Division, National Cancer Center Research Institute, Tokyo, Japan
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22
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Palamakumbura AH, Jeay S, Guo Y, Pischon N, Sommer P, Sonenshein GE, Trackman PC. The Propeptide Domain of Lysyl Oxidase Induces Phenotypic Reversion of Ras-transformed Cells. J Biol Chem 2004; 279:40593-600. [PMID: 15277520 DOI: 10.1074/jbc.m406639200] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lysyl oxidase is an extracellular enzyme critical for the normal biosynthesis of collagens and elastin. In addition, lysyl oxidase reverts ras-mediated transformation, and lysyl oxidase expression is down-regulated in human cancers. Since suramin inhibits growth factor signaling pathways and induces lysyl oxidase in ras-transformed NIH3T3 cells (RS485 cells), we sought to investigate the effects of suramin on the phenotype of transformed cells and the role of lysyl oxidase in mediating these effects. Suramin treatment resulted in a more normal phenotype as judged by growth rate, cell cycle parameters, and morphology. beta-aminopropionitrile, the selective inhibitor of lysyl oxidase enzyme activity, was remarkably unable to block suramin-induced reversion. By contrast, ectopic antisense lysyl oxidase demonstrated that lysyl oxidase gene expression mediated phenotypic reversion. Since lysyl oxidase is synthesized as a 50 kDa precursor and processed to a 30 kDa active enzyme and 18 kDa propeptide, the effects of these two products on the transformed phenotype of RS485 cells were then directly assessed in the absence of suramin. Here we report, for the first time, that the lysyl oxidase propeptide, and not the lysyl oxidase enzyme, inhibits ras-dependent transformation as determined by effects on cell proliferation assays, growth in soft agar, and Akt-dependent induction of NF-kappaB activity. Thus, the lysyl oxidase propeptide, which is released during extracellular proteolytic processing of pro-lysyl oxidase, functions to inhibit ras-dependent cell transformation.
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Affiliation(s)
- Amitha H Palamakumbura
- Division of Oral Biology, Boston University Goldman School of Dental Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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23
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Purro SA, Bisig CG, Contin MA, Barra HS, Arce CA. Post-translational incorporation of the antiproliferative agent azatyrosine into the C-terminus of alpha-tubulin. Biochem J 2003; 375:121-9. [PMID: 12852782 PMCID: PMC1223667 DOI: 10.1042/bj20030776] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Revised: 07/03/2003] [Accepted: 07/09/2003] [Indexed: 11/17/2022]
Abstract
Detyrosination/tyrosination of tubulin is a post-translational modification that occurs at the C-terminus of the alpha-subunit, giving rise to microtubules rich in either tyrosinated or detyrosinated tubulin which coexist in the cell. We hereby report that the tyrosine analogue, azatyrosine, can be incorporated into the C-terminus of alpha-tubulin instead of tyrosine. Azatyrosine is structurally identical to tyrosine except that a nitrogen atom replaces carbon-2 of the phenolic group. Azatyrosine competitively excluded incorporation of [14C]tyrosine into tubulin of soluble brain extract. A newly developed rabbit antibody specific to C-terminal azatyrosine was used to study incorporation of azatyrosine in cultured cells. When added to the culture medium (Ham's F12K), azatyrosine was incorporated into tubulin of glioma-derived C6 cells. This incorporation was reversible, i.e. after withdrawal of azatyrosine, tubulin lost azatyrosine and reincorporated tyrosine. Azatyrosinated tubulin self-assembled into microtubules to a similar degree as total tubulin both in vitro and in vivo. Studies by other groups have shown that treatment of certain types of cultured cancer cells with azatyrosine leads to reversion of phenotype to normal, and that administration of azatyrosine into animals harbouring human proto-oncogenic c-Ha- ras prevents tumour formation. These interesting observations led us to study this phenomenon in relation to tubulin status. Under conditions in which tubulin was mostly azatyrosinated, C6 cells remained viable but did not proliferate. After 7-10 days under these conditions, morphology changed from a fused, elongated shape to a rounded soma with thin processes. Incorporation of azatyrosine into the C-terminus of alpha-tubulin is proposed as one possible cause of reversion of the malignant phenotype.
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Affiliation(s)
- Silvia A Purro
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC (UNC-CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000-Córdoba, Argentina
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24
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Palamakumbura AH, Sommer P, Trackman PC. Autocrine growth factor regulation of lysyl oxidase expression in transformed fibroblasts. J Biol Chem 2003; 278:30781-7. [PMID: 12788924 DOI: 10.1074/jbc.m305238200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lysyl oxidase catalyzes oxidative deamination of peptidyl-lysine and hydroxylysine residues in collagens and lysine residues in elastin to form peptidyl aldehydes that are required for the formation of covalent cross-links in normal extracellular matrix biosynthesis. Lysyl oxidase in addition has tumor suppressor activity, and phenotypic reversion of transformed cell lines is accompanied by increased lysyl oxidase expression. The mechanism of low expression of lysyl oxidase in tumor cells is unknown. The present study investigates the hypothesis that autocrine growth factor pathways maintain low lysyl oxidase expression levels in c-H-ras-transformed fibroblasts (RS485 cell line). Autocrine pathways were blocked with suramin, a general inhibitor of growth factor receptor binding, and resulted in more than a 10-fold increase in lysyl oxidase expression and proenzyme production. This regulation was found to be reversible and occurred at the transcriptional level determined using lysyl oxidase promoter/reporter gene assays. Function blocking anti-fibroblast growth factor-2 (FGF-2) antibody enhanced lysyl oxidase expression in the absence of suramin. Finally, the addition of FGF-2 to suramin-treated cells completely reversed suramin stimulation of lysyl oxidase mRNA levels. Data support that an FGF-2 autocrine pathway inhibits lysyl oxidase transcription in the tumorigenic-transformed RS485 cell line. This finding may be of therapeutic significance and, in addition, provides a new experimental approach to investigate the mechanism of the tumor suppressor activity of lysyl oxidase.
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Affiliation(s)
- Amitha H Palamakumbura
- Boston University Goldman School of Dental Medicine, Division of Oral Biology, Boston, Massachusetts 02118, USA
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25
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Giampuzzi M, Oleggini R, Di Donato A. Altered adhesion features and signal transduction in NRK-49F cells transformed by down-regulation of lysyl oxidase. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1647:239-44. [PMID: 12686140 DOI: 10.1016/s1570-9639(03)00058-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Lysyl oxidase (LOX) down-regulation induced an oncogenic phenotype in NRK-49F. This event was accompanied by a constitutive activation of ras oncogene and down-regulation of PDGF beta receptor, among other important phenotypic and molecular modifications. In the present paper we show that ras activation is not accompanied by a constitutive activation of the MAP kinases as expected. Surprisingly, even if MAPK-independent, ras activation was accompanied by a constitutive Ser(63) and Ser(73) phosphorylation of c-jun, a further downstream target of ras. Although rare, this ras alternative pathway has been described. Since ras alone is seldom able to trigger cell transformation and the transformed phenotype showed clearly an abnormal adhesion pattern, we investigated the main molecules involved in cell-cell adhesion. In fact, we found that beta-catenin was up-regulated, escaping the glycogen synthase kinase-3 beta (GSK-3 beta) control, through unclear mechanisms. Its nuclear accumulation was accompanied by an up-regulation of cyclin D1, as classically described in the activation of the Wnt/beta-catenin signal pathway. We believe that the resulting up-regulation of cyclin D1 acted in synergy with ras to induce the cell transformation.
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Affiliation(s)
- Monia Giampuzzi
- Laboratorio di Nefrologia, Istituto G. Gaslini, Largo G. Gaslini, 5, 16147 Genova, Italy
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26
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Giampuzzi M, Oleggini R, Di Donato A. Demonstration of in vitro interaction between tumor suppressor lysyl oxidase and histones H1 and H2: definition of the regions involved. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1647:245-51. [PMID: 12686141 DOI: 10.1016/s1570-9639(03)00059-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Lysyl oxidase (LOX) is the enzyme that cross-links extracellular collagen and tropoelastin and is involved in tumor suppressor activity. Based on the existent homologies between lysine-rich regions of tropoelastin and the "lysine-rich" histone H1, we tested the possibility that H1 could be a new nuclear target. Our study shows that LOX could actually interact specifically not only with histone H1, but also with histone H2. Mechanisms and significance of these interactions are discussed in detail.
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Affiliation(s)
- Monia Giampuzzi
- Laboratorio di Nefrologia, Istituto G. Gaslini, Largo G. Gaslini, 5, 16147 Genova, Italy
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27
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Jeay S, Pianetti S, Kagan HM, Sonenshein GE. Lysyl oxidase inhibits ras-mediated transformation by preventing activation of NF-kappa B. Mol Cell Biol 2003; 23:2251-63. [PMID: 12640111 PMCID: PMC150722 DOI: 10.1128/mcb.23.7.2251-2263.2003] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lysyl oxidase (LO), which catalyzes the oxidation of lysine residues, was previously shown to have anti-oncogenic activity on ras-transformed cells. Since oncogenic Ras mediates transformation, in part, through the activation of the transcription factor nuclear factor-kappa B (NF-kappa B), we tested here the effects of LO on NF-kappa B activity. Expression of LO in ras-transformed NIH 3T3 cells led to decreased NF-kappa B binding and activity, as well as the expression of the NF-kappa B target gene c-myc. Importantly, ectopic expression of LO led to a dramatic decrease in colony formation by ras-transformed NIH 3T3 cells, a finding comparable to the expression of the I kappa B alpha dominant-negative mutant, which could be rescued by p65/p50 NF-kappa B subunit expression. LO was unable to directly inhibit the activity of ectopically expressed p65 and c-Rel NF-kappa B subunits, suggesting that LO affected an upstream signaling pathway(s) induced by Ras. Consistent with this hypothesis, LO expression decreased both the rate of I kappa B alpha turnover and the activities of IKK alpha and IKK beta. Moreover, the ectopic expression of a constitutively active version of either kinase reversed the negative effects of LO. Ras can induce NF-kappa B via both the phosphatidylinositol 3-kinase (PI3K)/Akt and Raf/MEK pathways. LO potently downregulated the PI3K and Akt kinases, while partially inhibiting MEK kinase activity. Expression of a constitutively activated, myristylated Akt or PDK1 was able to counteract the effect of LO on NF-kappa B, whereas constitutively activated Raf was only partially effective. Importantly, LO blocked membrane localization of Akt and PDK1 in Ras-transformed cells. Overall, these results strongly argue that the anti-oncogenic effects of LO on ras-mediated transformation are due to its ability to inhibit signaling pathways that lead to activation of NF-kappa B.
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Affiliation(s)
- Sébastien Jeay
- Department of Biochemistry, Boston University Medical School, Boston, Massachusetts 02118, USA
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28
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Vasseur S, Malicet C, Calvo EL, Labrie C, Berthezene P, Dagorn JC, Iovanna JL. Gene expression profiling by DNA microarray analysis in mouse embryonic fibroblasts transformed by rasV12 mutated protein and the E1A oncogene. Mol Cancer 2003; 2:19. [PMID: 12685932 PMCID: PMC153489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2003] [Accepted: 03/19/2003] [Indexed: 03/01/2023] Open
Abstract
BACKGROUND Ras is an area of intensive biochemical and genetic studies and characterizing downstream components that relay ras-induced signals is clearly important. We used a systematic approach, based on DNA microarray technology to establish a first catalog of genes whose expression is altered by ras and, as such, potentially involved in the regulation of cell growth and transformation. RESULTS We used DNA microarrays to analyze gene expression profiles of rasV12/E1A-transformed mouse embryonic fibroblasts. Among the approximately 12,000 genes and ESTs analyzed, 815 showed altered expression in rasV12/E1A-transformed fibroblasts, compared to control fibroblasts, of which 203 corresponded to ESTs. Among known genes, 202 were up-regulated and 410 were down-regulated. About one half of genes encoding transcription factors, signaling proteins, membrane proteins, channels or apoptosis-related proteins was up-regulated whereas the other half was down-regulated. Interestingly, most of the genes encoding structural proteins, secretory proteins, receptors, extracellular matrix components, and cytosolic proteins were down-regulated whereas genes encoding DNA-associated proteins (involved in DNA replication and reparation) and cell growth-related proteins were up-regulated. These data may explain, at least in part, the behavior of transformed cells in that down-regulation of structural proteins, extracellular matrix components, secretory proteins and receptors is consistent with reversion of the phenotype of transformed cells towards a less differentiated phenotype, and up-regulation of cell growth-related proteins and DNA-associated proteins is consistent with their accelerated growth. Yet, we also found very unexpected results. For example, proteases and inhibitors of proteases as well as all 8 angiogenic factors present on the array were down-regulated in transformed fibroblasts although they are generally up-regulated in cancers. This observation suggests that, in human cancers, proteases, protease inhibitors and angiogenic factors could be regulated through a mechanism disconnected from ras activation. CONCLUSIONS This study established a first catalog of genes whose expression is altered upon fibroblast transformation by rasV12/E1A. This catalog is representative of the genome but not exhaustive, because only one third of expressed genes was examined. In addition, contribution to ras signaling of post-transcriptional and post-translational modifications was not addressed. Yet, the information gathered should be quite useful to future investigations on the molecular mechanisms of oncogenic transformation.
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Affiliation(s)
- Sophie Vasseur
- Centre de Recherche INSERM EMI 0116, 163 Avenue de Luminy, BP172, 13009 Marseille, France
| | - Cédric Malicet
- Centre de Recherche INSERM EMI 0116, 163 Avenue de Luminy, BP172, 13009 Marseille, France
| | - Ezequiel L Calvo
- Molecular Endocrinology and Oncology Research Center, Laval University Medical Center 2705 Laurier Boulevard, Quebec, G1V 4G2, Canada
| | - Claude Labrie
- Molecular Endocrinology and Oncology Research Center, Laval University Medical Center 2705 Laurier Boulevard, Quebec, G1V 4G2, Canada
| | - Patrice Berthezene
- Centre de Recherche INSERM EMI 0116, 163 Avenue de Luminy, BP172, 13009 Marseille, France
| | - Jean Charles Dagorn
- Centre de Recherche INSERM EMI 0116, 163 Avenue de Luminy, BP172, 13009 Marseille, France
| | - Juan Lucio Iovanna
- Centre de Recherche INSERM EMI 0116, 163 Avenue de Luminy, BP172, 13009 Marseille, France
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Vasseur S, Malicet C, Calvo EL, Labrie C, Berthezene P, Dagorn JC, Iovanna JL. Gene expression profiling by DNA microarray analysis in mouse embryonic fibroblasts transformed by rasV12 mutated protein and the E1A oncogene. Mol Cancer 2003. [PMID: 12685932 PMCID: PMC153489 DOI: 10.1186/1476-4598-2-19] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ras is an area of intensive biochemical and genetic studies and characterizing downstream components that relay ras-induced signals is clearly important. We used a systematic approach, based on DNA microarray technology to establish a first catalog of genes whose expression is altered by ras and, as such, potentially involved in the regulation of cell growth and transformation. RESULTS We used DNA microarrays to analyze gene expression profiles of rasV12/E1A-transformed mouse embryonic fibroblasts. Among the approximately 12,000 genes and ESTs analyzed, 815 showed altered expression in rasV12/E1A-transformed fibroblasts, compared to control fibroblasts, of which 203 corresponded to ESTs. Among known genes, 202 were up-regulated and 410 were down-regulated. About one half of genes encoding transcription factors, signaling proteins, membrane proteins, channels or apoptosis-related proteins was up-regulated whereas the other half was down-regulated. Interestingly, most of the genes encoding structural proteins, secretory proteins, receptors, extracellular matrix components, and cytosolic proteins were down-regulated whereas genes encoding DNA-associated proteins (involved in DNA replication and reparation) and cell growth-related proteins were up-regulated. These data may explain, at least in part, the behavior of transformed cells in that down-regulation of structural proteins, extracellular matrix components, secretory proteins and receptors is consistent with reversion of the phenotype of transformed cells towards a less differentiated phenotype, and up-regulation of cell growth-related proteins and DNA-associated proteins is consistent with their accelerated growth. Yet, we also found very unexpected results. For example, proteases and inhibitors of proteases as well as all 8 angiogenic factors present on the array were down-regulated in transformed fibroblasts although they are generally up-regulated in cancers. This observation suggests that, in human cancers, proteases, protease inhibitors and angiogenic factors could be regulated through a mechanism disconnected from ras activation. CONCLUSIONS This study established a first catalog of genes whose expression is altered upon fibroblast transformation by rasV12/E1A. This catalog is representative of the genome but not exhaustive, because only one third of expressed genes was examined. In addition, contribution to ras signaling of post-transcriptional and post-translational modifications was not addressed. Yet, the information gathered should be quite useful to future investigations on the molecular mechanisms of oncogenic transformation.
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Affiliation(s)
- Sophie Vasseur
- Centre de Recherche INSERM EMI 0116, 163 Avenue de Luminy, BP172, 13009 Marseille, France.
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30
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Giampuzzi M, Botti G, Cilli M, Gusmano R, Borel A, Sommer P, Di Donato A. Down-regulation of lysyl oxidase-induced tumorigenic transformation in NRK-49F cells characterized by constitutive activation of ras proto-oncogene. J Biol Chem 2001; 276:29226-32. [PMID: 11323426 DOI: 10.1074/jbc.m101695200] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Several investigations have suggested a putative tumor suppressor role for lysyl oxidase because it is down-regulated in many human and oncogene-induced tumors. To address this issue we down-regulated the enzyme in normal rat kidney fibroblasts by stable transfection of its cDNA in an antisense orientation. The selected clones revealed an absence of lysyl oxidase and dramatic phenotypic changes, interpretable as signs of transformation. The antisense lysyl oxidase clones showed, indeed, loose attachment to the plate and anchorage-independent growth and were highly tumorigenic in nude mice. Moreover, we found an impaired response of the PDGF and IGF-1 receptors to their ligands. In particular, the transformed cells showed a down-regulation of both PDGF receptors and expressed the 105-kDa isoform of the IGF-1 beta receptor, which was not present in the normal control cells. The lack of response to PDGF-BB has been described as a feature of many ras-transformed phenotypes. Therefore, we looked at the status of the p21(ras). Indeed, we found a significantly higher level of active p21(ras) both during steady-state growth and prolonged starvation. Our data reveal new evidence for a tumor suppressor activity of lysyl oxidase, highlighting its particular role in controlling Ras activation and growth factor dependence.
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Affiliation(s)
- M Giampuzzi
- Department of Nephrology, Istituto G. Gaslini, Largo G. Gaslini, 5, 16147 Genova, Italy
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Mäki JM, Kivirikko KI. Cloning and characterization of a fourth human lysyl oxidase isoenzyme. Biochem J 2001; 355:381-7. [PMID: 11284725 PMCID: PMC1221749 DOI: 10.1042/0264-6021:3550381] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We report here the complete cDNA sequence and exon-intron organization of the human lysyl oxidase-like (LOXL)3 gene, a new member of the lysyl oxidase (LO) gene family. The predicted polypeptide is 753 amino acids in length, including a signal peptide of 25 residues. The C-terminal region, residues 529-729, contains a LO domain similar to those in the LOX (the first characterized LO isoenzyme), LOXL and LOXL2 polypeptides. It possesses the putative copper binding sequence, and the lysine and tyrosine residues that form the lysyltyrosyl quinone cofactor. The N-terminal region, which is similar to that in LOXL2 but not those in LOX and LOXL, contains four subregions similar to scavenger receptor cysteine-rich domains and a putative nuclear localization signal. Recombinant LOXL3, expressed in HT-1080 cells, was secreted into the culture medium but was not detected by immunofluorescence staining in nuclei. The LOXL3 mRNA is 3.1 kb in size and is expressed in many tissues, the highest levels among the tissues studied being seen in the placenta, heart, ovary, testis, small intestine and spleen.
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Affiliation(s)
- J M Mäki
- Collagen Research Unit, Biocenter and Department of Medical Biochemistry, University of Oulu, PO. BOX 5000, FIN-90014 Oulu, Finland
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32
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Giampuzzi M, Botti G, Di Duca M, Arata L, Ghiggeri G, Gusmano R, Ravazzolo R, Di Donato A. Lysyl oxidase activates the transcription activity of human collagene III promoter. Possible involvement of Ku antigen. J Biol Chem 2000; 275:36341-9. [PMID: 10942761 DOI: 10.1074/jbc.m003362200] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lysyl oxidase is an extracellular enzyme that controls the maturation of collagen and elastin. Lysyl oxidase and collagen III often show similar expression patterns in fibrotic tissues. Therefore, we investigated the influence of lysyl oxidase overexpression on the promoter activity of human COL3A1 gene. Our results showed that when COS-7 cells overexpressed the mature form of lysyl oxidase, the activity of the human COL3A1 promoter was increased up to an average of 12 times when tested by luciferase reporter assay. The effect was specific, because other promoters were not affected. Moreover, lysyl oxidase effect was abolished by beta-aminopropionitrile, a specific inhibitor of its catalytic activity. Electrophoretic mobility shift assay showed a binding activity in the region from -101 to -77 that was significantly increased by lysyl oxidase overexpression. The binding was specifically competed by the cold probe, and the mutagenesis of this region abolished both the binding activity in gel retardation and lysyl oxidase stimulation of COL3A1 promoter in transfection experiments. We identified the binding activity as Ku antigen in its two components: Ku80 and Ku70. This study suggests a new coordinated mechanism by which lysyl oxidase might control the development of fibrosis.
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Affiliation(s)
- M Giampuzzi
- Department of Nephrology, Gaslini Children's Hospital, Genova, Italy
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33
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Braun E, Rorman E, Lueders KK, Bar-Sinai A, Hochman J. Differential expression of intracisternal A-particle transcripts in immunogenic versus tumorigenic S49 murine lymphoma cells. Virology 2000; 277:136-46. [PMID: 11062044 DOI: 10.1006/viro.2000.0568] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tumorigenic S49 mouse lymphoma cells (T-25) were compared to their nontumorigenic (immunogenic) substrate-adherent descendants (T-25-Adh), using the differential display technique. A 784-bp fragment with 92% sequence homology to the intracisternal A-particle (IAP) element family was isolated from the latter cells. IAP sequences are endogenous, noninfectious retroviral elements that can undergo transpositions and act as mutagens. Expression of IAP transcripts (as detected by the isolated fragment) was 5- to 10-fold higher in T-25-Adh cells than in T-25 cells. IAP RT-PCR cDNA clones derived from the immunogenic T-25-Adh cells, but not from T-25 cells, contain two distinctive motifs: (i) a motif characteristic of IAP elements expressed in lymphoid cells (lymphocyte specific, LS); (ii) a nonapeptide sequence known to stimulate cytotoxic T lymphocytes in a leukemia cell line expressing IAP sequences. In addition, expression of transcripts containing these motifs is enhanced in the immunogenic cells as opposed to the tumorigenic cells. Furthermore, one of the IAP elements (belonging to the LS1 subfamily) is specifically hypomethylated in the DNA of the immunogenic cells. The above-mentioned relationship was strengthened when tumorigenic revertants derived from T-25-Adh cells, as well as independently selected tumorigenic and immunogenic S49 sublines, were studied. In all cases, enhanced immunogenicity was linked to the up-regulation of specific IAP elements. No transpositions of LS1 elements were observed among the different sublines studied. These findings suggest that, in the S49 lymphoma, selectively expressed IAP retroviral elements may function in a tumor suppressive capacity by affecting the immunogenic potential of these cells.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Cell Adhesion
- DNA, Complementary
- Gene Products, gag/chemistry
- Gene Products, gag/genetics
- Genes, Intracisternal A-Particle
- Genes, gag
- Lymphoma/genetics
- Lymphoma/virology
- Mice
- Molecular Sequence Data
- RNA, Messenger/genetics
- Sequence Alignment
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Transcription, Genetic
- Tumor Cells, Cultured
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Affiliation(s)
- E Braun
- Department of Cell and Animal Biology, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
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Monden Y, Hamano Takaku F, Shindo Okada N, Nishimura S. Azatyrosine. Mechanism of action for conversion of transformed phenotype to normal. Ann N Y Acad Sci 2000; 886:109-21. [PMID: 10667209 DOI: 10.1111/j.1749-6632.1999.tb09406.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Azatyrosine [L-beta-(5-hydroxy-2-pyridyl)-alanine] has the unique property of converting ras- or c-erbB-2 transformed phenotype to normal. The administration of azatyrosine also inhibits tumor formation in transgenic mice harboring the normal human c-Ha-ras which is mutated during treatment with various chemical carcinogens. To elucidate the molecular mechanism, we investigated how azatyrosine functions and what are its major targets. Azatyrosine functions downstream of ras; azatyrosine does not alter either the level of GTP-bound Ras or the total amount of Ras. Instead, azatyrosine inhibits the activation of c-Raf-1 kinase by oncogenic c-ErbB-2, resulting in inactivation of AP1. It is interesting that azatyrosine also restores the expression of the rhoB gene, the product of which regulates the formation of actin stress fibers. Azatyrosine is incorporated into cellular proteins to replace tyrosine. Several experiments indicate that replacement of tyrosine is likely to be a cause for its conversion of transformed phenotype to normal. To prove this hypothesis, we are attempting to develop a mutant of tyrosyl-tRNA synthetase that, unlike wild type, can aminoacylate azatyrosine more efficiently than can tyrosine.
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Affiliation(s)
- Y Monden
- Banyu Tsukuba Research Institute, Ibaraki, Japan
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Contente S, Kenyon K, Sriraman P, Subramanyan S, Friedman RM. Epigenetic inhibition of lysyl oxidase transcription after transformation by ras oncogene. Mol Cell Biochem 1999; 194:79-91. [PMID: 10391127 DOI: 10.1023/a:1006913122261] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Lysyl oxidase is an extracellular enzyme involved in connective tissue maturation that also acts as a phenotypic suppressor of the ras oncogene. To understand how this suppressor is controlled, gene transcription was studied and the promoter was characterized. Nuclear runoff transcription assays indicated that the markedly reduced amounts of lysyl oxidase message detected after ras transformation resulted from inhibition of lysyl oxidase transcription. Interferon-mediated phenotypic reversion of ras transformed cells, in which the ras oncogene continued to be expressed, was accompanied by the restoration of lysyl oxidase transcription. Reporter gene assay of a transfected mouse lysyl oxidase promoter indicated that it was active in the transformed background, despite the silencing of the endogenous lysyl oxidase promoter. The detection of comparable amounts of mRNA for transcription factors IRF-1 and IRF-2 in normal and ras-transformed cell lines suggests that the differential transcription of lysyl oxidase was not due to regulation of IRFs. Lysyl oxidase promoter activity was localized to a 126 bp region that includes two consensus TATA boxes with associated confirmed cap signals. Analysis of a human lysyl oxidase promoter sequence indicated similar promoter elements and extensive sequence identity with the mouse promoter. The binding of transcription factor AP2 to sites predicted in the control region was confirmed by DNase footprinting. Lysyl oxidase transcription was stimulated by dexamethasone treatment of cells, but this effect could not be assigned within the approximately 3 kb region tested in reporter gene constructs. The promoter activity of the lysyl oxidase reporter gene construct was completely abolished by in vitro DNA methylation, suggesting that the transcriptional suppression after transformation by the ras oncogene may involve DNA methylation.
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Affiliation(s)
- S Contente
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799, USA
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36
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Andreú T, Beckers T, Thoenes E, Hilgard P, von Melchner H. Gene trapping identifies inhibitors of oncogenic transformation. The tissue inhibitor of metalloproteinases-3 (TIMP3) and collagen type I alpha2 (COL1A2) are epidermal growth factor-regulated growth repressors. J Biol Chem 1998; 273:13848-54. [PMID: 9593730 DOI: 10.1074/jbc.273.22.13848] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A gene trap strategy has been used to identify genes that are repressed in cells transformed by an activated epidermal growth factor (EGF)/EGF receptor signal transduction pathway. EGF receptor-expressing NIH3T3 cells (HER1 cells) were infected with a retrovirus containing coding sequences for the human CD2 antigen and for secreted alkaline phosphatase in the U3 region. By selecting for and against CD2 expression, we obtained clones in which the gene trap had integrated into genes selectively repressed by EGF. Two of these clones encoded for the secreted extracellular matrix proteins TIMP3 and COL1A2. We show here that both genes are downstream targets of RAS and are specifically repressed by EGF-induced transformation. Moreover, this strategy tags tumor suppressor genes in their normal chromosomal location, thereby improving target-specific screens for antineoplastic drugs.
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Affiliation(s)
- T Andreú
- Laboratory for Molecular Hematology, Department of Hematology, University of Frankfurt Medical School, Weismüllerstrasse 45, Frankfurt am Main, Germany
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37
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Di Donato A, Lacal JC, Di Duca M, Giampuzzi M, Ghiggeri G, Gusmano R. Micro-injection of recombinant lysyl oxidase blocks oncogenic p21-Ha-Ras and progesterone effects on Xenopus laevis oocyte maturation. FEBS Lett 1997; 419:63-8. [PMID: 9426221 DOI: 10.1016/s0014-5793(97)01420-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Previous evidence suggested an anti-oncogenic role for lysyl oxidase, mainly in ras-transformed cells. Here we prove that recombinant lysyl oxidase is actually able to antagonize p21-Ha-Ras-induced Xenopus laevis oocyte maturation. Lysyl oxidase was also effective on progesterone-dependent maturation, indicating a block lying downstream of Ras. Maturation induced by activated 'maturation promoting factor', normally triggered by progesterone, was also inhibited by lysyl oxidase. Finally, lysyl oxidase did not abolish p42Erk2 phosphorylation upon maturation triggering, suggesting a block downstream of Erk2. Further investigation showed that lysyl oxidase action depends on protein synthesis and is therefore probably mediated by a newly synthesized protein.
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Affiliation(s)
- A Di Donato
- Department of Nephrology, Institute G. Gaslini, Genoa, Italy.
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38
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Li W, Nellaiappan K, Strassmaier T, Graham L, Thomas KM, Kagan HM. Localization and activity of lysyl oxidase within nuclei of fibrogenic cells. Proc Natl Acad Sci U S A 1997; 94:12817-22. [PMID: 9371758 PMCID: PMC24221 DOI: 10.1073/pnas.94.24.12817] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Lysyl oxidase (EC 1.4.3.13) oxidizes peptidyl lysine to peptidyl aldehyde residues within collagen and elastin, thus initiating formation of the covalent cross-linkages that insolubilize these extracellular proteins. Recent findings raise the possibility that this enzyme may also function intracellularly. The present study provides evidence by immunocytochemical confocal microscopy, Western blot analysis, enzyme assays, and chemical analyses for lysyl oxidase reaction products that this enzyme is present and active within rat vascular smooth muscle cell nuclei. Confocal microscopy indicates its presence within nuclei of 3T3 fibroblasts, as well.
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Affiliation(s)
- W Li
- Department of Biochemistry, Boston University School of Medicine, MA 02118, USA
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39
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Ambros IM, Rumpler S, Luegmayr A, Hattinger CM, Strehl S, Kovar H, Gadner H, Ambros PF. Neuroblastoma cells can actively eliminate supernumerary MYCN gene copies by micronucleus formation--sign of tumour cell revertance? Eur J Cancer 1997; 33:2043-9. [PMID: 9516850 DOI: 10.1016/s0959-8049(97)00204-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Human neuroblastoma cell lines frequently exhibit MYCN amplification and many are characterised by the presence of morphologically distinct cell types. The neuronal cells (N-cells) and the so-called flat cells (F-cells) are thought to represent manifestations of different neural crest cell lineages and are considered to be the consequence of neuroblastoma cell pluripotency. In this study, various neuroblastoma cell lines were examined for micronuclei. In F-cells of neuroblastoma cell lines with extrachromosomally amplified MYCN, we observed the frequent occurrence of micronuclei. Using fluorescence in situ hybridisation (FISH) with a MYCN specific probe, we demonstrated that these micronuclei were packed with MYCN hybridisation signals. In addition, in a minor percentage of cells, MYCN signals occurred in clusters, adhered to the nuclear membrane and aggregated in nuclear protrusions. In F-cells, a substantial reduction or lack of amplified MYCN copies was observed. These observations let us conclude that extrachromosomally amplified genes can be actively eliminated from the nucleus resulting in a dramatic loss of amplified sequences in the F-cells. Moreover, reduction or loss of amplified sequences in F-cells was shown to be accompanied by downregulation of MYCN expression, by a decrease in proliferative activity and by upregulation of molecules of the major histocompatibility complex class I (MHC I). Interestingly, F-cells are not restricted to neuroblastoma cell cultures, but also occur in cell lines of other tissue origin. All F-cells share important biological features, interpreted as cell revertance, i.e. loss of the malignant phenotype and properties. This fact, together with the demonstration that neuroblastoma cells do not differentiate into Schwann cells in vivo [1] Ambros et al. NEJM 1996, 334, 1505-1511, do not support the hypothesis that F-cells represent Schwannian/glial differentiation in vitro. We therefore postulate that the elimination of amplified MYCN gene copies in cultivated neuroblastoma cells is in line with the phenomenon of tumour cell revertance.
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Affiliation(s)
- I M Ambros
- Children's Cancer Research Institute CCRI, St. Anna Kinderspital, Vienna, Austria
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40
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Sers C, Emmenegger U, Husmann K, Bucher K, Andres AC, Schäfer R. Growth-inhibitory activity and downregulation of the class II tumor-suppressor gene H-rev107 in tumor cell lines and experimental tumors. J Cell Biol 1997; 136:935-44. [PMID: 9049257 PMCID: PMC2132501 DOI: 10.1083/jcb.136.4.935] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The H-rev107 gene is a new class II tumor suppressor, as defined by its reversible downregulation and growth-inhibiting capacity in HRAS transformed cell lines. Overexpression of the H-rev107 cDNA in HRAS-transformed ANR4 hepatoma cells or in FE-8 fibroblasts resulted in 75% reduction of colony formation. Cell populations of H-rev107 transfectants showed an attenuated tumor formation in nude mice. Cells explanted from tumors or maintained in cell culture for an extended period of time no longer exhibited detectable levels of the H-rev107 protein, suggesting strong selection against H-rev107 expression in vitro and in vivo. Expression of the truncated form of H-rev107 lacking the COOH-terminal membrane associated domain of 25 amino acids, had a weaker inhibitory effect on proliferation in vitro and was unable to attenuate tumor growth in nude mice. The H-rev107 mRNA is expressed in most adult rat tissues, and immunohistochemical analysis showed expression of the protein in differentiated epithelial cells of stomach, of colon and small intestine, in kidney, bladder, esophagus, and in tracheal and bronchial epithelium. H-rev107 gene transcription is downregulated in rat cell lines derived from liver, kidney, and pancreatic tumors and also in experimental mammary tumors expressing a RAS transgene. In colon carcinoma cell lines only minute amounts of protein were detectable. Thus, downregulation of H-rev107 expression may occur at the level of mRNA or protein.
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Affiliation(s)
- C Sers
- Department of Pathology, University of Zurich, Switzerland.
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Saux CJL, Gleyzal C, Raccurt M, Sommer P. Functional analysis of the lysyl oxidase promoter in myofibroblast-like clones of 3T6 fibroblast. J Cell Biochem 1997. [DOI: 10.1002/(sici)1097-4644(199702)64:2<328::aid-jcb14>3.0.co;2-e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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42
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Peyrol S, Raccurt M, Gerard F, Gleyzal C, Grimaud JA, Sommer P. Lysyl oxidase gene expression in the stromal reaction to in situ and invasive ductal breast carcinoma. THE AMERICAN JOURNAL OF PATHOLOGY 1997; 150:497-507. [PMID: 9033266 PMCID: PMC1858268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Lysyl oxidase is involved in the main pathway of collagen and elastin cross-linking: it has a role in the maturation of fibrillar matrix proteins in fibrosing processes and dictates their stability against metalloproteases. The stromal reaction patterns in ductal breast carcinoma are known to be morphologically varied. This has raised the hypothesis that there might be a differential expression of the lysyl oxidase gene as a function of stromal reaction pattern. The present study investigates this potential correlation and the role of matrix protein cross-linking in stromal differentiation. Lysyl oxidase was detected by immunohistochemistry and lysyl oxidase gene expression by in situ hybridization. Maximal expression was observed in myofibroblasts and myoepithelial cells around in situ tumors and in the reactive fibrosis facing the invasion front of infiltrating tumors. The lysyl oxidase substrates were observed in parallel, resulting in the stabilization of a scar-like peritumor barrier. In contrast, a lack of lysyl oxidase was associated with the loose or scirrhous stroma accompanying invading tumors; here, in situ hybridization revealed type I collagen synthesis, resulting in the deposition of non-cross-linked matrix proteins susceptible to degradation. The early development of a cross-linked matrix around ductal breast carcinoma suggests a possible bost defense mechanism, whereas the synchronous or late stromal reaction lacking lysyl oxidase favors tumor dispersion.
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Affiliation(s)
- S Peyrol
- Unité de Pathologie des Fibroses, Institut Pasteur de Lyon, France
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43
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Ohashi K, Tstsumi M, Nakajima Y, Nakano H, Konishi Y. Ki-ras point mutations and proliferation activity in biliary tract carcinomas. Br J Cancer 1996; 74:930-5. [PMID: 8826860 PMCID: PMC2074747 DOI: 10.1038/bjc.1996.459] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The association between Ki-ras mutations and proliferation activity was investigated in a comprehensive series of biliary tract carcinomas (BTCs). We precisely microdissected samples of tissue from paraffin-embedded sections of 77 BTCs including 22 intrahepatic cholangiocarcinomas (ICCs), 36 extrahepatic cholangiocarcinomas (ECCs), and 19 gall bladder carcinomas (GBCs). Ki-ras mutations at exons 1 and 2 were determined by the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method and confirmed by direct sequencing. Proliferation activity was immunohistochemically assessed to generate proliferating cell nuclear antigen labelling indices (PCNA LIs). Ki-ras mutations were detected in 10 of 22 ICCs (45%), 24 of 36 ECCs (67%), and in 16 of 19 GBCs (84%). The frequency of Ki-ras mutations in peripheral type ICCs was 33% (4 of 12) and that in the hilar type ICCs was 60% (6 of 10). In ECCs the highest value of 82% (9 of 11) was found for carcinomas located in the lower part of the biliary tree. Mean PCNA LI in mutation-positive BTCs was significantly elevated compared with the mutation-negative value. These results indicate frequent involvement of Ki-ras mutations in BTCs, especially in GBCs and in distal ECCs, and that carcinomas harbouring a mutation feature high cell proliferation activity.
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Affiliation(s)
- K Ohashi
- First Department of Surgery, Nara Medical University, Japan
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44
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Lavrovsky V, Dong Z, Ma WY, Colburn N. Drug-induced reversion of progression phenotype is accompanied by reversion of AP-1 phenotype in JB6 cells. In Vitro Cell Dev Biol Anim 1996; 32:234-7. [PMID: 8727048 DOI: 10.1007/bf02722951] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Transformed JB6 cells can be stably reverted to nontransformed phenotype by AP-1 inhibiting gluccorticoid fluocinolone (FA) and cAMP elevator forskolin (FN), yielding stable revertants of promotion resistant (P-) and promotion sensitive (P+) phenotypes. AP-1 activity of nontransformed P- and P+ revertant clones was decreased under a variety of experimental conditions compared with their transformed counterparts. Moreover, AP-1 activity in P+ cells under anchorage-independent conditions was induced by 12-0-tetradecanoyl-phorbol-13-acetate (TPA) while AP-1 activity in the reverted P- cells was not induced, just as observed for the original P+ and P- variants. Taken together these data suggest that changes in AP-1 activity may be one key mediator not only of forward progression but also of reversion of tumor cells to nontransformed phenotype. In addition, the higher transfection efficiency of the new reverted P- and P+ cells renders them useful for studying the role of transcription factors in tumor promotion.
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Affiliation(s)
- V Lavrovsky
- Laboratory of Viral Carcinogenesis, NCI-FCRDC, Frederick, Maryland 21702-1201, USA
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Csiszar K, Entersz I, Trackman PC, Samid D, Boyd CD. Functional analysis of the promoter and first intron of the human lysyl oxidase gene. Mol Biol Rep 1996; 23:97-108. [PMID: 8983023 DOI: 10.1007/bf00424435] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Alterations in the synthesis and activity of lysyl oxidase occur concomitant with developmental changes in collagen and elastin deposition and with the pathogenesis of several acquired and heritable connective tissue disorders. To begin to unravel the mechanisms that control lysyloxidase gene expression, we have previously reported the complete exon-intron structure of the human lysyl oxidase gene. We have now sequenced this entire gene, including all six introns and 4 kb of DNA 5' of exon 1. Analysis of over 13 kb of intervening sequence and 5' flanking sequence revealed a concentration of conserved consensus sequence elements within the first intron and 1 kb immediately 5' of exon 1. Analysis of intron 1 and the 5' flanking domain, using recombinant plasmids containing the chloramphenicol acetyl transferase (CAT) reporter gene, identified functional DNA sequence elements within these non-coding domains responsible for inhibition and up-regulation of CAT activity in primary cultures of human skin fibroblasts, in smooth muscle cells, revertant cells derived from an osteosarcoma cell line and malignant c-Ha-ras-transformed osteosarcoma cells. DNA sequence elements within intron 1, in particular, resulted in a marked increase in CAT reporter activity in cultured fibroblasts, smooth muscle cells and osteosarcoma cells. In c-Ha-ras-transformed osteosarcoma cells, however, no such enhancer activity of intron 1 sequence was observed. Ras-transformed osteosarcoma cells exhibited reduced steady-state levels of lysyl oxidase mRNA that was primarily controlled through reduced transcription of the lysyl oxidase gene. The lack of any up-regulation of CAT activity in these ras-transformed cells by sequence elements within intron 1 suggests a complex interaction between cis-acting domains and trans-acting transcriptional factors in the 5' promoter domain and the first intron of the lysyl oxidase gene.
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Affiliation(s)
- K Csiszar
- Department of Surgery, UMDNJ-Robert Wood Johnson Medical School, New Brunswick 08903, USA
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Ohizumi I, Tanemura M, Kaihoh S. A novel styryl diphenylamine derivative reverts the transformed phenotype of human fibrosarcoma HT1080 cells. Br J Cancer 1995; 72:1219-23. [PMID: 7577471 PMCID: PMC2033950 DOI: 10.1038/bjc.1995.489] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Revertant cells, which can be isolated from transformed cells, are flat, non-transformed variants that have contributed to the elucidation of mechanisms involved in cell transformation. We have discovered that a novel styryl diphenylamine derivative converts human fibrosarcoma HT1080 cells into revertant cells. This compound induces flat cell morphology and causes a decrease in proliferative rate. The flat revertant cells not only exhibit a reduction in saturation density at confluence, but also lose the ability to proliferate in soft agar. Furthermore, their tumorigenicity is reduced when injected s.c. into athymic nude mice. The compound alters morphology in three out of seven cancer cell lines and has a potent growth inhibitory effect in six of these lines. In contrast, it has only low levels of cytotoxicity for three normal diploid cell lines. These findings indicate that this styryl diphenylamine derivative has the potential to suppress the malignant phenotype of cancer cells without profound cytotoxicity in non-transformed cells.
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Affiliation(s)
- I Ohizumi
- Department of Cancer Research, Fuji Gotemba Research Laboratories, Chugai Pharmaceutical Co. Ltd., Shizuoka, Japan
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Oberhuber H, Seliger B, Schäfer R. Partial restoration of pre-transformation levels of lysyl oxidase and transin mRNAs in phenotypic ras revertants. Mol Carcinog 1995; 12:198-204. [PMID: 7727041 DOI: 10.1002/mc.2940120404] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Neoplastic transformation mediated by ras oncogenes is associated with deregulated expression of genes encoding, for example, various proteases, lysyl oxidase, and smooth-muscle alpha-actin. To define the role of these genes in the initiation or maintenance of the ras-transformed state, we compared their steady-state mRNA levels in two different sets of preneoplastic fibroblast lines, ras-transformed clones, and phenotypic revertants derived from them. Compared with the preneoplastic fibroblasts, the ras-transformed derivatives exhibited elevated levels of cathepsin L (major excreted protein), transin (stromelysin I, matrix metalloproteinase-3), and collagenase I (matrix metalloproteinase-1) mRNA but undetectable levels of lysyl oxidase mRNA. Partial restoration of lysyl oxidase transcription was observed in four of five phenotypic revertants derived from rat FE-8 and NIHpEJcl3 cells. The elevated levels of transin mRNA found in NIHpEJcl3 cells were diminished to the pretransformation level in interferon revertants but were not reduced in phenotypic rat FE-8 revertants expressing a high level of the ras oncoprotein. High steady-state levels of collagenase I mRNA were dependent on ras expression but were not closely associated with the transformed phenotype. High levels of cathepsin L mRNA were associated with neither high ras expression nor neoplastic transformation. The downregulation of smooth-muscle alpha-actin, characteristic of transformed cell lines, was not reversible in phenotypic revertants.
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Affiliation(s)
- H Oberhuber
- Department of Pathology, University Hospital, Zürich, Switzerland
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Kim Y, Boyd CD, Csiszar K. A new gene with sequence and structural similarity to the gene encoding human lysyl oxidase. J Biol Chem 1995; 270:7176-82. [PMID: 7706256 DOI: 10.1074/jbc.270.13.7176] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have isolated a number of recombinant clones from a human skin fibroblast cDNA library that contain extensive sequence homology to several coding domains within the human lysyl oxidase mRNA. Using one of these lysyl oxidase-like cDNAs, we obtained several overlapping genomic DNA recombinants. Restriction mapping and DNA sequence analysis revealed that the complete sequence of the lysyl oxidase-like mRNA was encoded by seven exons distributed throughout 25 kilobases of genomic DNA. Exons 2-6 encoded the region of greatest homology to lysyl oxidase. The size of these five exons, moreover, was exactly the same as the size of the corresponding exons within the lysyl oxidase gene. Northern blot analysis also revealed the concomitant appearance of lysyl oxidase and lysyl oxidase-like mRNA in several human tissues. It appears therefore that the genes encoding lysyl oxidase and a lysyl oxidase-like protein share a common evolutionary origin and may also be functionally related.
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Affiliation(s)
- Y Kim
- Department of Surgery, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick 08903, USA
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Dimaculangan DD, Chawla A, Boak A, Kagan HM, Lazar MA. Retinoic acid prevents downregulation of ras recision gene/lysyl oxidase early in adipocyte differentiation. Differentiation 1994; 58:47-52. [PMID: 7867896 DOI: 10.1046/j.1432-0436.1994.5810047.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Adipocyte differentiation of 3T3-L1 cells is a complex process which is inhibited by retinoic acid (RA). Since RA acts by nuclear receptors which directly regulate gene expression, we postulate that the primary targets of RA action in this system are genes which are regulated early in adipose conversion. In this study, we demonstrate the use of the differential display technique to search for early events in adipose commitment which are sensitive to RA. A mRNA was identified on the basis of its RA-dependent gene expression 24 h after initiation of a standard differentiation protocol. Molecular cloning of the cDNA revealed it to be identical to the ras recision gene (rrg), for lysyl oxidase. Indeed, two mRNAs identical to those recognized by lysyl oxidase probes were expressed in preadipocytes and tandemly repressed with 24 h of exposure to differentiation conditions. Lysyl oxidase activity was similarly reduced in the media of differentiated cells. RA completely blocked the differ-entiation-related reduction in rrg/lysyl oxidase gene expression, although RA had no independent stimulatory effect on rrg/lysyl oxidase expression in cells not exposed to differentiating conditions. Thus, differential display has been successfully used to identify rrg/lysyl oxidase as an early marker for adipose conversion that is responsive to RA.
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Affiliation(s)
- D D Dimaculangan
- Department of Medicine and Genetics, University of Pennsylvania School of Medicine, Philadelphia 19104
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Naora H, Xu ZZ, Miyahara K, Liszczynsky H, Seno S. Gene ecology: a cis-acting gene-to-gene interaction due to the spatial arrangement of genes in chromosomes affects neighbouring transfected c-H-ras expression. Chromosome Res 1994; 2:171-83. [PMID: 8069461 DOI: 10.1007/bf01553317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A cis-acting interference between gene activities, which occurs when two genes lie on the same DNA strand and have an intergenic distance less than a defined length, was previously deduced when chromosomal organizations of various higher eukaryote nuclear genes in clusters were compared. In order to investigate such an interference due to arrangement of genes along chromosomes, we have isolated a few cell lines which possessed (i) human mutated c-H-ras fused with the mouse mammary tumour virus long terminal repeat and (ii) the E. coli xanthine-guanine phosphoribosyltransferase (gpt) gene with the SV40 promoter, on the same or on different DNA strands, separated by a short intergenic distance or unlinked. Since the cancerous phenotype of a cell can be readily identified due to c-H-ras expression, we examined in these cell lines whether continuous c-H-ras expression, induced by dexamethasone, is disturbed through a cis-acting gene-to-gene interaction when the expression of the neighbouring gpt gene is enforced and as a result, the cancerous state of a cell is converted to the 'normal' state. The enforced expression of the neighbouring gpt gene was shown to alter c-H-ras expression, and thus reversible conversion of a cell between cancerous and normal states occurred only when the cell possessed an optimum number of the gene pair, in which both c-H-ras and the gpt gene were on the same DNA strand. This implies that the spatial arrangement of genes in chromosomes plays an important role in the regulation of gene expression in a cluster.
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Affiliation(s)
- H Naora
- Research School of Biological Sciences, Australian National University, Canberra
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