Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.4.3.13 (lysyl oxidase)
 1,248 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neoplastic transformation mediated by ras oncogenes is associated with down-regulation of gene expression. We have constructed a subtracted complementary DNA library from preneoplastic rat 208F fibroblasts by hybridizing with mRNA from a ras-transformed subclone. One of the complementary DNA clones identified by this approach encodes the 3' end of lysyl oxidase, the homologue of the mouse ras recision gene. Expression of lysyl oxidase was almost completely down-regulated in two clones of H-ras-transformed 208F cells (FE-8 and FE-56). We isolated a set of spontaneous phenotypic revertants of FE-8 cells (designated FSR) by cloning at limiting dilution. FSR revertant clones expressed high levels of lysyl oxidase and H-ras mRNA but grew only poorly in semisolid agar medium as opposed to anchorage-independent parental FE-8 cells. We obtained subclones of FSR cells which displayed again the transformed morphology of FE-8 cells but required anchorage for growth and continued to express high levels of lysyl oxidase mRNA. Thus, expression of lysyl oxidase correlated with the suppression of anchorage-independent growth rather than with flat morphology. Lysyl oxidase might be a useful marker to distinguish between different aspects of reversion and transformation.
Cancer Res 1993 Oct 01
PMID:Up-regulation of lysyl oxidase in spontaneous revertants of H-ras-transformed rat fibroblasts. 769

The transcriptional activator IFN regulatory factor 1 (IRF-1) and its antagonistic repressor IRF-2 are regulators of the IFN system. IRF-1 also manifests tumor suppressive activity, and its inactivation could contribute to the development of human hematopoietic malignancies. Here, we report the identification of the lysyl oxidase gene as a target gene of IRF-1. An IRF response element was identified in the lysyl oxidase gene promoter. We also demonstrate that the transformed phenotype of ras-expressing embryonic fibroblasts with a null mutation in the IRF-1 allele could be suppressed by the expression of the lysyl oxidase cDNA, implicating its potential role in tumor suppression. Thus, the regulation of the lysyl oxidase gene by IRF-1 could contribute to the multistep process of malignant transformation.
Cancer Res 1996 May 15
PMID:Identification of the lysyl oxidase gene as target of the antioncogenic transcription factor, IRF-1, and its possible role in tumor suppression. 862 21

To identify genes associated with prostate cancer progression, we developed a strategy involving the use of differential display PCR and a panel of genetically matched primary tumor- and metastasis-derived mouse prostate cancer cell lines. We analyzed sequences that were differentially stimulated by transforming growth factor-beta1 in primary tumor-versus metastasis-derived cell lines, based on our previous studies indicating that acquisition of differential responses to this growth factor could result in phenotypic traits that facilitate tumor metastasis from specific cell clones within the primary tumor. Using this system, we isolated and sequenced a cDNA fragment that encoded mouse lysyl oxidase (LO) and was induced by transforming growth factor-beta1 in primary tumor but not in metastasis-derived cells. Northern blotting analysis revealed increased LO expression in a panel of primary tumor cell lines but significantly reduced or nondetectable expression in their matched metastatic counterparts. Further in situ hybridization analysis revealed LO expression in normal mouse prostate epithelium but, in most cases, progressive loss of expression in primary prostate cancer and associated metastatic lesions. Importantly, in situ hybridization studies of normal human prostate and prostate malignancies revealed a similar loss of expression during progression to metastasis. The progressive loss of LO expression during prostate cancer progression provides information that may increase our understanding of the mechanisms that underlie this disease. In addition, LO may provide a useful molecular marker and/or establish a novel therapeutic target for prostate cancer.
Cancer Res 1998 Mar 15
PMID:Reduced lysyl oxidase messenger RNA levels in experimental and human prostate cancer. 951 17

Renal cell carcinoma (RCC) are frequently chemo- and radiation resistant. Thus, there is a need for identifying biological features of these cells that could serve as alternative therapeutic targets. We performed suppression subtractive hybridization (SSH) on patient-matched normal renal and RCC tissue to identify variably regulated genes. 11 genes were strongly up-regulated or selectively expressed in more than one RCC tissue or cell line. Screening of filters containing cancer-related cDNAs confirmed overexpression of 3 of these genes and 3 additional genes were identified. These 14 differentially expressed genes, only 6 of which have previously been associated with RCC, are related to tumour growth/survival (EGFR, cyclin D1, insulin-like growth factor-binding protein-1 and a MLRQ sub-unit homologue of the NADH:ubiquinone oxidoreductase complex), angiogenesis (vascular endothelial growth factor, endothelial PAS domain protein-1, ceruloplasmin, angiopoietin-related protein 2) and cell adhesion/motility (protocadherin 2, cadherin 6, autotaxin, vimentin, lysyl oxidase and semaphorin G). Since some of these genes were overexpressed in 80-90% of RCC tissues, it is important to evaluate their suitability as therapeutic targets.
Br J Cancer 2001 Nov 02
PMID:Identification of human renal cell carcinoma associated genes by suppression subtractive hybridization. 1172 Apr 77

Oral submucous fibrosis (OSF) is a precancerous condition of the oral cavity. It is a collagen-related disorder induced by betel quid chewing, a habit that is common in Taiwan. However, the cumulative exposure to betel quids varies in OSF patients. It seems that there is individual susceptibility to betel quid-induced OSF. This study compared the association of OSF and polymorphisms of six collagen-related genes, collagen 1A1 and 1A2 (COL1A1 and COL1A2), collagenase-1 (COLase), transforming growth factor beta1 (TGF-beta1), lysyl oxidase (LYOXase), and cystatin C (CST3), between patients with low and high exposure to betel quids. A total of 166 patients with OSF from a medical center and 284 betel quid chewers who were free of OSF and oral cancer, from the same hospital and five townships, were recruited. PCR-based restriction fragment length polymorphism assays were used to determine the genotypes of the six collagen-related genes situated on different chromosomes. We found that the genotypes associated with the highest OSF risk for collagen 1A1, collagen 1A2, collagenase-1, transforming growth factor beta1, lysyl oxidase, and cystatin C were CC, AA, TT, CC, AA, and AA, respectively, for the low-exposure group, and TT, BB, AA, CC, GG, and AA, respectively, for the high-exposure group. A trend was noted for an increased risk of OSF with increasing number of high-risk alleles for those with both high and low exposures for betel quid. The cell selection mechanism of oral fibroblasts is proposed to explain the effect of the modification of cumulative betel quid exposure on the risk profiles of collagen-related genes. These results imply that susceptibility to OSF could involve multigenic mechanisms modified by the betel quid-exposure dose.
Cancer Epidemiol Biomarkers Prev 2002 Jul
PMID:Interaction of collagen-related genes and susceptibility to betel quid-induced oral submucous fibrosis. 1210 Nov 12

We identified previously an up-regulation in lysyl oxidase (LOX) expression,an extracellular matrix remodeling enzyme, in a highly invasive/metastatic human breast cancer cell line, MDA-MB-231, compared with MCF-7, a poorly invasive/nonmetastatic breast cancer cell line. In this study, we demonstrate that the mRNA expression of LOX and other LOX family members [lysyl oxidase-like (LOXL), LOXL2, LOXL3, and LOXL4] was observed only in breast cancer cells with a highly invasive/metastatic phenotype but not in poorly invasive/nonmetastatic breast cancer cells. LOX and LOXL2 showed the strongest association with invasive potential in both highly invasive/metastatic breast cancer cell lines tested (MDA-MB-231 and Hs578T). To determine whether LOX is directly involved in breast cancer invasion, LOX antisense oligonucleotides were transfected into MDA-MB-231 and Hs578T cells, and found to inhibit invasion through a collagen IV/laminin/gelatin matrix in vitro compared with LOX sense oligonucleotide-treated and untreated controls. In addition, treatment of MDA-MB-231 and Hs578T cells with beta-aminopropionitrile (an irreversible inhibitor of LOX enzymatic activity) decreased invasive activity. Conversely, MCF-7 cells transfected with the murine LOX gene demonstrated a 2-fold increase in invasiveness that was reversible by the addition of beta-aminopropionitrile in a dose-dependent manner. In addition, endogenous LOX mRNA expression was induced when MCF-7 cells were cultured in the presence of fibroblast conditioned medium or conditioned matrix, suggesting a role for stromal fibroblasts in LOX regulation in breast cancer cells. Moreover, the correlation of LOX up-regulation and invasive/metastatic potential was additionally demonstrated in rat prostatic tumor cell lines, and human cutaneous and uveal melanoma cell lines. These results provide substantial new evidence that LOX is involved in cancer cell invasion.
Cancer Res 2002 Aug 01
PMID:A molecular role for lysyl oxidase in breast cancer invasion. 1215 58

The lysyl oxidase gene family members function as extracellular matrix modulating enzymes. We have found that another member of this family, lysyl oxidase related protein-1 (LOR-1), is highly expressed in metastatic breast cancer-derived cell lines but not in the nonmetastatic estrogen-dependent MCF-7 cells. Furthermore, LOR-1 expression in periductal tumor cells of breast carcinomas is significantly correlated with increased tumor malignancy. MCF-7 cells expressing recombinant LOR-1 formed estrogen-dependent tumors that developed much slower than tumors derived from empty vector-transfected MCF-7 cells. The cells of these LOR-1-expressing tumors were surrounded by a high concentration of dense collagen fibers, and the tumors contained many fibrotic foci. Induction of fibrosis in vivo by lysyl oxidase-like enzymes has never been observed before and suggests that LOR-1 may function as an autonomous inducer of fibrosis. The appearance of fibrotic foci in spontaneous breast cancer tumors is correlated with poor prognosis and metastasis, and we, therefore, examined the invasiveness of the LOR-1-expressing tumors. LOR-1-expressing MCF-7 cells invaded the pseudocapsules surrounding the tumors. In contrast, vector-transfected MCF-7 cells did not invade the pseudocapsules. This observation suggests that LOR-1 enhances the malignancy of the tumors. Furthermore, the LOR-1-expressing tumor cells invaded blood vessels, nerves, and muscles adjacent to the tumor, indicating that the LOR-1-expressing MCF-7 cells acquired metastatic properties. We conclude that LOR-1 promotes tumor fibrosis and tumor invasiveness simultaneously, which indicates that these two processes may be associated.
Cancer Res 2003 Apr 01
PMID:Lysyl oxidase-related protein-1 promotes tumor fibrosis and tumor progression in vivo. 1267 Sep 20

We have previously shown that lysyl oxidase (LOX) mRNA is up-regulated in invasive breast cancer cells and that catalytically active LOX facilitates in vitro cell invasion. Here we validate our in vitro studies by showing that LOX expression is up-regulated in distant metastatic breast cancer tissues compared with primary cancer tissues. To elucidate the mechanism by which LOX facilitates cell invasion, we show that catalytically active LOX regulates in vitro motility/migration and cell-matrix adhesion formation. Treatment of the invasive breast cancer cell lines, Hs578T and MDA-MB-231, with beta-aminopropionitrile (betaAPN), an irreversible inhibitor of LOX catalytic activity, leads to a significant decrease in cell motility/migration and adhesion formation. Conversely, poorly invasive MCF-7 cells expressing LOX (MCF-7/LOX32-His) showed an increase in migration and adhesion that was reversible with the addition of betaAPN. Moreover, a decrease in activated focal adhesion kinase (FAK) and Src kinase, key proteins involved in adhesion complex turnover, was observed when invasive breast cancer cells were treated with betaAPN. Additionally, FAK and Src activation was increased in MCF-7/LOX32-His cells, which was reversible on betaAPN treatment. Hydrogen peroxide was produced as a by-product of LOX activity and the removal of hydrogen peroxide by catalase treatment in invasive breast cancer cells led to a dose-dependent loss in Src activation. These results suggest that LOX facilitates migration and cell-matrix adhesion formation in invasive breast cancer cells through a hydrogen peroxide-mediated mechanism involving the FAK/Src signaling pathway. These data show the need to target LOX for treatment of aggressive breast cancer.
Cancer Res 2005 Dec 15
PMID:Lysyl oxidase regulates breast cancer cell migration and adhesion through a hydrogen peroxide-mediated mechanism. 1635 51

Lysyl oxidase initiates the enzymatic stage of collagen and elastin cross-linking. Among five isoforms comprising the lysyl oxidase family, LOX is the better studied. LOX is associated to an antitumor activity in ras-transformed fibroblasts, and its expression is down-regulated in many carcinomas. The aim of this work was to shed light on LOX functions within the epidermis by studying its expression in human basal and squamous cell carcinomas and analyzing the effect of its enzymatic activity inhibition and protein absence on human keratinocytes behavior in a skin equivalent. In both carcinomas, LOX expression by epidermal tumor cells was lacking, while it was up-regulated around invading tumor cells in association with the stromal reaction. Lysyl oxidase activity inhibition using beta-aminoproprionitrile in a skin equivalent model prepared with both primary human keratinocytes and HaCaT cell line affected keratin 10 and filaggrin expression and disorganized the collagen network and the basement membrane. In spite of all these changes, no invasion phenotype was observed. Modelization of the invasive phenotype was only noticed in the skin equivalent developed with LOX antisense HaCaT cell line, where the protein LOX is specifically absent. Our results clearly indicate that lysyl oxidase enzymatic activity is essential not only for the integrity maintenance of the dermis but also for the homeostasis of the epidermis. Moreover, LOX protein plays a role in the skin carcinomas and invasion but not through its enzymatic activity.
Clin Cancer Res 2006 Mar 01
PMID:The lysyl oxidase LOX is absent in basal and squamous cell carcinomas and its knockdown induces an invading phenotype in a skin equivalent model. 1653 69

Metastasis is a multistep process responsible for most cancer deaths, and it can be influenced by both the immediate microenvironment (cell-cell or cell-matrix interactions) and the extended tumour microenvironment (for example vascularization). Hypoxia (low oxygen) is clinically associated with metastasis and poor patient outcome, although the underlying processes remain unclear. Microarray studies have shown the expression of lysyl oxidase (LOX) to be elevated in hypoxic human tumour cells. Paradoxically, LOX expression is associated with both tumour suppression and tumour progression, and its role in tumorigenesis seems dependent on cellular location, cell type and transformation status. Here we show that LOX expression is regulated by hypoxia-inducible factor (HIF) and is associated with hypoxia in human breast and head and neck tumours. Patients with high LOX-expressing tumours have poor distant metastasis-free and overall survivals. Inhibition of LOX eliminates metastasis in mice with orthotopically grown breast cancer tumours. Mechanistically, secreted LOX is responsible for the invasive properties of hypoxic human cancer cells through focal adhesion kinase activity and cell to matrix adhesion. Furthermore, LOX may be required to create a niche permissive for metastatic growth. Our findings indicate that LOX is essential for hypoxia-induced metastasis and is a good therapeutic target for preventing and treating metastases.
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PMID:Lysyl oxidase is essential for hypoxia-induced metastasis. 3218 47


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