N-tert-butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe (BOC2) inhibits the angiogenic activity of heparin-binding growth factors

Abstract

The peptides N-tert-butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe (BOC2) and BOC-Met-Leu-Phe (BOC1) are widely used antagonists of formyl peptide receptors (FPRs), BOC2 acting as an FPR1/FPR2 antagonist whereas BOC1 inhibits FPR1 only. Extensive investigations have been performed by using these FPR antagonists as a tool to assess the role of FPRs in physiological and pathological conditions. Based on previous observations from our laboratory, we assessed the possibility that BOC2 may exert also a direct inhibitory effect on the angiogenic activity of vascular endothelial growth factor-A (VEGF-A). Our data demonstrate that BOC2, but not BOC1, inhibits the angiogenic activity of heparin-binding VEGF-A with no effect on the activity of the non-heparin-binding VEGF-A isoform. Endothelial cell-based bioassays, surface plasmon resonance analysis, and computer modeling indicate that BOC2 may interact with the heparin-binding domain of VEGF-A, thus competing for heparin interaction and preventing the binding of VEGF-A to tyrosine kinase receptor VEGFR2, its phosphorylation and downstream signaling. In addition, BOC2 inhibits the interaction of a variety of heparin-binding angiogenic growth factors with heparin, including fibroblast growth factor 2 (FGF2) whose angiogenic activity is blocked by the compound. Accordingly, BOC2 suppresses the angiogenic potential of human tumor cell lines that co-express VEGF-A and FGF2. Thus, BOC2 appears to act as a novel multi-heparin-binding growth factor antagonist. These findings caution about the interpretation of FPR-focusing experimental data obtained with this compound and set the basis for the design of novel BOC2-derived, FPR independent multi-target angiogenesis inhibitors.

Melatonin ameliorates endoplasmic reticulum stress in N2a neuroblastoma cell hypoxia-reoxygenation injury by activating the AMPK-Pak2 pathway

“…Changes in cellular antioxidants were determined to analyze redox balance in N2a cells treated with melatonin and/or AMPK inhibition. *P < 0.05 vs. control group, #P < 0.05 vs. HR group, @P < 0.05 vs. HR + melatonin group first investigation illustrating the neuronal protective effects and potential mechanisms of melatonin and Pak2 in the context of brain IR injury in vitro (Deussen 2018;Na et al 2018).…”

Enterobactin induces the chemokine, interleukin-8, from intestinal epithelia by chelating intracellular iron

“…47 To elucidate the role of FPRs in Ent-induced IL-8 secretion in IECs, we sought to inhibit FPR1/ FPR2 signaling by using the pan-FPR antagonist, N-tert-butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe (Boc2). 48 Pre-treating HT29 cells with Boc2 at either 1, 10 or 50 µM concentrations were sufficient in preventing Ent-induced IL-8 secretion in HT29 cells ( Figure 6(a,b)). The inhibitory effect of 10 µM Boc2 was not averted despite increasing the concentration of Ent from 1 to 50 µM ( Figure 6(b)).…”

Angiogenesis-Inflammation Cross Talk in Diabetic Retinopathy: Novel Insights From the Chick Embryo Chorioallantoic Membrane/Human Vitreous Platform

“…Three FPRs have been identified in humans (FPR1-FPR3), characterized by different ligand properties, biological function and cellular distribution (118). Among them, FPR3 appears to mediate pro-angiogenic responses in human endothelial cells (119). It must be pointed out that the murine genome contains eight FPR-related sequences (120) whereas the presence of FPR gene ortholog(s) in birds is more uncertain.…”