Planta Medica International Open 2017; 4(S 01): S1-S202
DOI: 10.1055/s-0037-1608107
Poster Session
Georg Thieme Verlag KG Stuttgart · New York

Inhibition of angiogenic key features: the Amaryllidaceae alkaloid narciclasine diminishes proliferation, migration, tube formation and sprouting of human endothelial cells

J Bräutigam
1   Institute of Pharmaceutical Biology, Biocenter, Goethe University, Frankfurt/Main, Germany
,
L Nguyen Dieu
2   Department of Pharmacognosy, University of Vienna, Vienna, Austria
,
E Heiss
2   Department of Pharmacognosy, University of Vienna, Vienna, Austria
,
I Bischoff
1   Institute of Pharmaceutical Biology, Biocenter, Goethe University, Frankfurt/Main, Germany
,
R Fürst
1   Institute of Pharmaceutical Biology, Biocenter, Goethe University, Frankfurt/Main, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
24 October 2017 (online)

 

Narciclasine, an isocarbostyril alkaloid from Narcissus and Haemanthus species, exhibits potent in vitro and in vivo cytotoxicity against cancer cells. Surprisingly, potential effects of narciclasine on endothelial cells in the context of tumor angiogenesis have been neglected so far. Thus, we aimed to elucidate the action of narciclasine on in vitro key features of angiogenesis, i.e. on the proliferation, migration, tube formation and angiogenic sprouting of human primary endothelial cells (ECs). Treatment of ECs with narciclasine up to a concentration of 300 nM (48h) did not affect the metabolic activity, while cell proliferation was concentration-dependently reduced (IC50: 61 nM). Moreover, narciclasine (300 nM) reduced the undirected migration of ECs (scratch assay) by 54% and the chemotactic migration (Boyden chamber) by 77%. In a 2D migration assay, narciclasine lowered the accumulated (50%) and euclidean distance (44%), diminished the velocity (50%) and attenuated the y-forward migration index by 30%. Most importantly, the alkaloid reduced both the formation of endothelial tube-like structures on Matrigel and the growth factor-induced sprouting of EC spheroids (100 and 300 nM). Regarding the underlying mode of action, narciclasine did neither inhibit the activation of Erk and Akt (Western blot analysis), nor interfere with endothelial nitric oxide production (arginine/citrulline conversion). Interestingly, ECs partially recovered their capacity to migrate when the Rho-associated protein kinase (ROCK) was inhibited, indicating that narciclasine might act by ROCK activation. Correspondingly, microscopical analysis of the cytoskeleton revealed that narciclasine increased the formation of F-actin stress fibers, which is mediated via the Rho-ROCK signaling pathway. Taken together, the isocarbostyril alkaloid narciclasine effectively decreases key features of angiogenesis in ECs. Thus, narciclasine might represent a promising anti-angiogenic lead compound. Moreover, we suggest that the compound's mode of action partially depends on the activation of the ROCK signaling pathway.