DIFFERENT EFFECTS OF ANGIOGENESIS INHIBITORS IFN-α AND TIMP-1 ON LYMPHANGIOGENESIS

Abstract

This study was designed to examine theeffects of angiogenesis inhibitors IFN-α andTIMP-1 on lymphangiogenesis. We culturedlymphatic endothelial (LE) cells from pigthoracic ducts and performed morphologicalobservations using light microscopy, TEM,and confocal microscopy to confirm theirlymphatic origin. We tested these cells forgrowth inhibition by angiogenesis inhibitorsIFN-α and TIMP-1 using both the scrapingline and MTT methods. In addition, weanalyzed apoptosis using the Hoechst andCaspase staining methods. Finally, we testedIFN-α and TIMP-1 using in vivo inhibitoryassays. By morphological observations, all LEcells in vivo and in vitro were found to be ofvery similar morphology. Both in vitroinhibitory assays of scraping line and MTTshowed significant differences for the IFN-αtreatment (p<0.01) and no significantdifference for TIMP-1. Hoechst and Caspaseapoptosis assays demonstrated that IFN-αcould induce apoptosis of LE cells, andTIMP-1 had little effect. IFN-α and TIMP-1inhibitory in vivo assays showed a lack ofhealing following IFN-α treatment comparedto control and TIMP-1 treatment. In summary,these different angiogenesis inhibitorshave different effects on lymphangiogenesis.IFN-α inhibits proliferation and migration ofLE cells in a dose-dependent fashion andinduces apoptosis of LE cells while TIMP-1has no significant inhibitory effects onproliferation, migration, or inducing apoptosis.