Decastatin, a novel Non-Collagenous 1 domain from collagen type X, harbors a specific fragment with antiangiogenic properties.

Abstract

The NC1 domains of collagens have been shown to possess antiangiogenic potential and, therefore, are of therapeutic interest for cancer. However, endostatin and other NC1 domains have not been successful in clinical tests. Therefore, we used evolutionary conservation to perform molecular deconstruction of the domains to further understand their structure-activity relationship, thereby deciphering their antiangiogenic potential. Homology exploration revealed that collagen type X contains a highly interesting NC1 domain (decastatin), with several sequences showing significant homology with vastatin, which is a known collagen type VIII-derived NC1 domain. For comparison, endostatin and vastatin were split into fragments, some of which contained highly conserved regions. The testing of these peptides revealed that the peptides containing conserved regions induced signaling, and fragment four of decastatin showed the highest potency of all fragments, with a calculated IC 50 value of 2.7 μM in the human umbilical vein endothelial cell (HUVEC)-based tube formation assay, which is like that of an intact NC1 domain. Notably, the corresponding fragment from vastatin (V4) also inhibited tube formation, suggesting that this region is of therapeutic interest. In summary, we used evolutionary conservation to identify a novel NC1 domain of collagen type X, a collagen playing a role in angiogenesis of the growth plate. Furthermore, we provided data indicating that the antiangiogenic activity of NC1 domain-derived peptides reside within their conserved domains. As a result, we identified a fragment called Decastatin fragment 4 (D4) derived from the NC1 domain of collagen type X, and which has potent antiangiogenic activity.