title: MCF-7 cells expressing nuclear associated lysyl oxidase-like 2 (LOXL2) exhibit an epithelial-to-mesenchymal transition (EMT) phenotype and are highly invasive in vitro.
abstract: LOXL2 is a copper- and lysine tyrosylquinone-dependent amine oxidase that has been proposed to function both extracellularly and intracellularly to activate oncogenic signaling pathways leading to EMT and invasion of breast cancer cells. In this study, we selected MCF-7 cells that stably express forms of recombinant LOXL2 differing in their subcellular localizations and catalytic competencies. This enabled us to dissect the molecular functions of intracellular and extracellular LOXL2s and examine their contributions to breast cancer metastasis/invasion. We discovered that secreted LOXL2 (~100-kDa) is N-glycosylated at Asn-455 and Asn-644, whereas intracellular LOXL2 (~75-kDa) is nonglycosylated and N-terminally processed, and is primarily associated with the nucleus. Both forms of LOXL2 can oxidize lysine in solution. However, we found that expression of intracellular LOXL2 is more strongly associated with EMT and invasiveness than secreted LOXL2 in vitro. The results indicate that nuclear associated LOXL2 contributes to the stabilization of Snail1 transcription factor at the protein level to induce EMT and promote invasion in vitro, through repression of E-cadherin, occludin, and estrogen receptor-α, and up-regulation of vimentin, fibronectin, and MT1-MMP.
authors.affiliation: From the Department of Chemistry, The University of Kansas, Lawrence, Kansas 66045.
authors.forename: Hee-Jung
authors.initials: HJ
authors.lastname: Moon
authors.affiliation: From the Department of Chemistry, The University of Kansas, Lawrence, Kansas 66045.
authors.forename: Joel
authors.initials: J
authors.lastname: Finney
authors.affiliation: From the Department of Chemistry, The University of Kansas, Lawrence, Kansas 66045.
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.affiliation: the KU Microscopy and Analytical Imaging Laboratory, The University of Kansas, Lawrence, Kansas 66045, and.
authors.forename: David
authors.initials: D
authors.lastname: Moore
authors.affiliation: the Department of Cancer Biology and The University of Kansas Cancer Center, The University of Kansas Medical Center, Kansas City, Kansas 66160.
authors.forename: Danny R
authors.initials: DR
authors.lastname: Welch
authors.affiliation: From the Department of Chemistry, The University of Kansas, Lawrence, Kansas 66045,. Electronic address: mmure@ku.edu.
authors.forename: Minae
authors.initials: M
authors.lastname: Mure
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000096:biosynthesis* / Q000235:genetics; D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006031:Glycosylation; D006801:Humans; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D009363:Neoplasm Proteins; D000594:Amino Acid Oxidoreductases; C119091:LOXL2 protein, human
keywords: Breast Cancer; Cell Invasion; Epithelial-to-mesenchymal Transition; Lysyl Oxidase; Lysyl Oxidase-Like 2; Post-translational Modification; Site-directed Mutagenesis