The propeptide domain of lysyl oxidase induces phenotypic reversion of ras-transformed cells.
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.
Division of Oral Biology, Boston University Goldman School of Dental Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
Amitha H
AH
Palamakumbura
Sébastien
S
Jeay
Ying
Y
Guo
Nicole
N
Pischon
Pascal
P
Sommer
Gail E
GE
Sonenshein
Philip C
PC
Trackman
D000629:Aminopropionitrile / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D002453:Cell Cycle; D002455:Cell Division; D002461:Cell Line, Transformed; D003094:Collagen / Q000737:chemistry; D004549:Elastin / Q000737:chemistry; D005822:Genetic Vectors; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D016328:NF-kappa B / Q000378:metabolism; D041681:NIH 3T3 Cells; D016376:Oligonucleotides, Antisense / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D008249:Protein-Lysine 6-Oxidase / Q000737:chemistry* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D013498:Suramin / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection
D000970:Antineoplastic Agents; D016328:NF-kappa B; D016376:Oligonucleotides, Antisense; D010455:Peptides; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D000629:Aminopropionitrile; D013498:Suramin; D003094:Collagen; D004549:Elastin; D008156:Luciferases; D008249:Protein-Lysine 6-Oxidase; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt