Cysteine Cathepsins S and L Modulate Anti-angiogenic Activities of Human Endostatin

Florian Veillard,Ahlame Saidi,Roberta E Burden,Christopher J Scott,Ludovic Gillet,Fabien Lecaille,Gilles Lalmanach

doi:10.1074/jbc.m111.284869

Florian Veillard, Ahlame Saidi + Show 5 more

Open Access

https://doi.org/10.1074/jbc.m111.284869

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Abstract

Human endostatin, a potent anti-angiogenic protein, is generated by release of the C terminus of collagen XVIII. Here, we propose that cysteine cathepsins are involved in both the liberation and activation of bioactive endostatin fragments, thus regulating their anti-angiogenic properties. Cathepsins B, S, and L efficiently cleaved in vitro FRET peptides that encompass the hinge region corresponding to the N terminus of endostatin. However, in human umbilical vein endothelial cell-based assays, silencing of cathepsins S and L, but not cathepsin B, impaired the generation of the ∼22-kDa endostatin species. Moreover, cathepsins L and S released two peptides from endostatin with increased angiostatic properties and both encompassing the NGR sequence, a vasculature homing motif. The G10T peptide (residues 1455-1464: collagen XVIII numbering) displayed compelling anti-proliferative (EC(50) = 0.23 nm) and proapoptotic properties. G10T inhibited aminopeptidase N (APN/CD13) and reduced tube formation of endothelial cells in a manner similar to bestatin. Combination of G10T with bestatin resulted in no further increase in anti-angiogenic activity. Taken together, these data suggest that endostatin-derived peptides may represent novel molecular links between cathepsins and APN/CD13 in the regulation of angiogenesis.

Highlights

Cathepsins participate to the release of endostatin, a potent anti-angiogenic protein
Cathepsin B cleaved Endo-09 between Leu-1345 and Val1346, which does correspond to the N terminus of the shorter molecular variety of endostatin (ϳ20 kDa) found in Specificity constants for the hydrolysis of FRET peptides (Endo-01 to Endo-10) corresponding to the hinge region of the C-terminal domain of collagen XVIII
Since the late 1990s, an increasing number of anti-angiogenic factors released by proteases were identified, and most studies have focused on their therapeutic impact in high pharmaceutical doses, in controlling tumor progression [37]

Summary

Introduction

Cathepsins participate to the release of endostatin, a potent anti-angiogenic protein. Results: Both cathepsins L and S generate two peptides from human endostatin with increased angiostatic properties. Conclusion: Endostatin-derived peptides reduce tube formation of endothelial cells. Significance: Endostatin-derived peptides may represent novel molecular links between cysteine cathepsins and aminopeptidase N in the regulation of angiogenesis. A potent anti-angiogenic protein, is generated by release of the C terminus of collagen XVIII. We propose that cysteine cathepsins are involved in both the liberation and activation of bioactive endostatin fragments, regulating their anti-angiogenic properties. Cathepsins L and S released two peptides from endostatin with increased angiostatic properties and both encompassing the NGR sequence, a vasculature homing motif. Combination of G10T with bestatin resulted in no further increase in anti-angiogenic activity Taken together, these data suggest that endostatin-derived peptides may represent novel molecular links between cathepsins and APN/CD13 in the regulation of angiogenesis

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Conclusion