Studies on the Design and Synthesis of Marine Peptide Analogues and Their Ability to Promote Proliferation in HUVECs and Zebrafish.

In our previous studies, tripeptide 1 was found to induce angiogenesis in zebrafish embryos and in HUVECs. Based on the lead compound 1, seven new marine tripeptide analogues 2-8 have been designed and synthesized in this paper to evaluate the effects on promoting cellular proliferation in human endothelial cells (HUVECs) and zebrafish. Among them, compounds 5-7 possessed more remarkable increasing proliferation effects than other compounds, and the EC50 values of these and the leading compound 1 were 1.0 +/- 0.002 M, 1.0 +/- 0.0005 M, 0.88 +/- 0.0972 M, and 1.31 +/- 0.0926 M, respectively. Furthermore, 5-7 could enhance migrations (58.5%, 80.66% and 60.71% increment after culturing 48 h, respectively) and invasions (49.08%, 47.24% and 56.24% increase, respectively) in HUVECs compared with the vehicle control. The results revealed that the tripeptide including l-Tyrosine or d-Proline fragments instead of l-Alanine of leading compound 1 would contribute to HUVECs' proliferation. Taking the place of the original (l-Lys-l-Ala) segment of leading compound 1, a new fragment (l-Arg-d-Val) expressed higher performance in bioactivity in HUVECs. In addition, compound 7 could promote angiogenesis in zebrafish assay and it was more interesting that it also could repair damaged blood vessels in PTK787-induced zebrafish at a low concentration. The above data indicate that these peptides have potential implications for further evaluation in cytothesis studies.