Brekhman V.,Technion - Israel Institute of Technology |
Lugassie J.,Technion - Israel Institute of Technology |
Zaffryar-Eilot S.,Technion - Israel Institute of Technology |
Sabo E.,Technion - Israel Institute of Technology |
And 4 more authors.
Lysyl oxidase-like protein-2 (LOXL2) induces epithelial to mesenchymal transition and promotes invasiveness. To understand the mechanisms involved, we examined the effect of LOXL2 overexpression in MCF-7 cells on gene expression. We found that LOXL2 upregulated the expression of receptor activity modifying protein-3 (RAMP3). Expression of RAMP3 in MDA-MB-231 cells in which LOXL2 expression was inhibited restored vimentin expression, invasiveness, and tumor development. Inhibition of RAMP3 expression in MDAMB-231 cells mimicked the effects produced by inhibition of LOXL2 expression and was accompanied by inhibition of p38 phosphorylation. LOXL2 overexpression in these cells did not restore invasiveness, suggesting that RAMP3 functions downstream to LOXL2. LOXL2 and RAMP3 are strongly coexpressed in human colon, breast, and gastric carcinomas but not in normal colon or gastric epithelial cells. RAMP3 associates with several G-protein-coupled receptors forming receptors for peptides, such as adrenomedullin and amylin. We hypothesized that RAMP3 could function as a transducer of autocrine signals induced by such peptides. However, the proinvasive effects of RAMP3 could not be abrogated following inhibition of the expression or activity of these peptides. Our experiments suggest that the protumorigenic effects of LOXL2 are partially mediated by RAMP3 and that RAMP3 inhibitors may function as antitumorigenic agents.-Brekhman, V., Lugassie, J., Zaffryar-Eilot, S., Sabo, E., Kessler, O., Smith, V., Golding, H., Neufeld, G. Receptor activity modifying protein-3 mediates the protumorigenic activity of lysyl oxidase-like protein-2. © FASEB. Source
Barry-Hamilton V.,Arresto BioSciences |
Spangler R.,Arresto BioSciences |
Marshall D.,Arresto BioSciences |
McCauley S.,Arresto BioSciences |
And 19 more authors.
We have identified a new role for the matrix enzyme lysyl oxidase-like-2 (LOXL2) in the creation and maintenance of the pathologic microenvironment of cancer and fibrotic disease. Our analysis of biopsies from human tumors and fibrotic lung and liver tissues revealed an increase in LOXL2 in disease-associated stroma and limited expression in healthy tissues. Targeting LOXL2 with an inhibitory monoclonal antibody (AB0023) was efficacious in both primary and metastatic xenograft models of cancer, as well as in liver and lung fibrosis models. Inhibition of LOXL2 resulted in a marked reduction in activated fibroblasts, desmoplasia and endothelial cells, decreased production of growth factors and cytokines and decreased transforming growth factor-β 2 (TGF-β 2) pathway signaling. AB0023 outperformed the small-molecule lysyl oxidase inhibitor β 2-aminoproprionitrile. The efficacy and safety of LOXL2-specific AB0023 represents a new therapeutic approach with broad applicability in oncologic and fibrotic diseases. © 2010 Nature America, Inc. All rights reserved. Source
Rodriguez H.M.,Arresto BioSciences |
Vaysberg M.,Arresto BioSciences |
Mikels A.,Arresto BioSciences |
McCauley S.,Arresto BioSciences |
And 3 more authors.
Journal of Biological Chemistry
In this report, we assessed the steady-state enzymatic activity of lysyl oxidase-like 2 (LOXL2) against the substrates 1,5-diaminopentane (DAP), spermine, and fibrillar type I collagen. We find that both DAP and spermine are capable of activating LOXL2 to the same extent and have similar Michaelis constants (Km∼1 mM) and catalytic rates (kcat ∼ 0.02 s-1). We also show that LOXL2 is capable of being inhibited by a known suicide inhibitor of lysyl oxidase (LOX), β-aminopropionitrile, which we find is a potent inhibitor of LOXL2 activity. The modality of inhibition of β-aminopropionitrile was also examined and found to be competitive with respect to the substrates DAP and spermine. In addition, we identified an antibody inhibitor (AB0023) of LOXL2 enzymatic function and have found that the inhibition occurs in a non-competitive manner with respect to both spermine and DAP. The binding epitope of AB0023 was mapped to the scavenger receptor cysteine-rich domain four of human LOXL2. AB0023 binds to a region remote from the catalytic domain making AB0023 an allosteric inhibitor of LOXL2. This affords AB0023 several advantages, because it is specific for LOXL2 and inhibits the enzymatic function of LOXL2 in a non-competitive manner thereby allowing inhibition of LOXL2 regardless of substrate concentration. These results suggest that antibody allosteric modulators of enzymatic function represent a novel drug development strategy and, in the context of LOXL2, suggest that inhibitors such as these might be useful therapeutics in oncology, fibrosis, and inflammation. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc. Source