Expression and Anti-angiogenic Function Analysis of Tenomodulin, a Tendon and Eye Specifically Expressed Glycoprotein Sharing Homology with Chondromodulin-I

Abstract

Abstract: : Backgrounds: Tenomodulin (TeM) is a type II transmembrane glycoprotein which contains a domain homologous to chondromodulin-I (ChM-I), a cartilage-derived angiogenesis inhibitor, at its C-terminal region. TeM transcripts were found in association with hypovascular tissues such as tendon, ligament and sclerocornea of the eye. Material and Methods: To explore the anti-angiogenic activity of TeM, we constructed adenoviral vectors to deliver recombinant, soluble proteins that include the C-terminal domain of human TeM (Glu²⁰² - Val³¹⁷: Ad-shTeM) or that of human ChM-I (Glu²¹⁵ - Val³³⁴: Ad-shChM-I), and then we carried out the adenoviral gene transduction into the human retinal endothelial cells (HRECs) for in vitro assay. Inhibition of tumorigenesis via the anti-angiogenic action of TeM and/or ChM-I was also examined in a melanoma xenograft model in which the cancer cells were co-injected with Ad-shTeM or Ad-shChM-I for overexpressing a secreted form of the protein. Results: In the culture of HRECs, adenoviral infection of Ad-shTeM or Ad-shChM-I resulted in a significant impairment of DAN synthesis, adhesion, spreading migration, and tube forming activity of cells. The co-injection resulted in effective inhibition of tumor growth by the significant suppression of vascular invasion. Conclusion: These results indicate that TeM carries a functional anti-angiogenic domain at the C-terminus as well as ChM-I and the possibility of both TeM and ChM-I as candidates for use in gene therapy approaches aimed at the treatment of angiogenesis.

Keywords: adenovirus • gene transfer/gene therapy • neovascularization