Effects of a novel cyclic RGD peptidomimetic on cell proliferation, migration and angiogenic activity in human endothelial cells

Abstract

Background

Cyclic RGD peptidomimetics containing a bifunctional diketopiperazine scaffold are a novel class of high-affinity ligands for the integrins α _Vβ ₃and α _Vβ ₅. Since integrins are a promising target for the modulation of normal and pathological angiogenesis, the present study aimed at characterizing the ability of the RGD peptidomimetic cyclo[DKP-RGD] 1proliferation, migration and network formation in human umbilical vein endothelial cells (HUVEC).

Methods

Cell viability was assessed by flow cytometry and annexin V (ANX)/propidium iodide (PI) staining. Cell proliferation was evaluated by the ELISA measurement of bromodeoxyuridine (BrdU) incorporation. Network formation by HUVEC cultured in Matrigel-coated plates was evaluated by optical microscopy and image analysis. Integrin subunit mRNA expression was assessed by real time-PCR and Akt phosphorylation by western blot analysis.

Results

Cyclo[DKP-RGD] 1does not affect cell viability and proliferation either in resting conditions or in the presence of the pro-angiogenic growth factors VEGF, EGF, FGF, and IGF-I. Addition of cyclo[DKP-RGD] 1however significantly decreased network formation induced by pro-angiogenic growth factors or by IL-8. Cyclo[DKP-RGD] 1did not affect mRNA levels of α _V, β ₃or β ₅integrin subunits, however it significantly reduced the phosphorylation of Akt.

Conclusions

Cyclo[DKP-RGD] 1can be a potential modulator of angiogenesis induced by different growth factors, possibly devoid of the adverse effects of cytotoxic RGD peptidomimetic analogues.