The Aplidin analogs PM01215 and PM02781 inhibit angiogenesis in vitro and in vivo.
BACKGROUND
Novel synthesized analogs of Aplidin, PM01215 and PM02781, were tested for antiangiogenic effects on primary human endothelial cells in vitro and for inhibition of angiogenesis and tumor growth in vivo.


METHODS
Antiangiogenic activity of both derivatives was evaluated by real-time cell proliferation, capillary tube formation and vascular endothelial growth factor (VEGF)-induced spheroid sprouting assays. Distribution of endothelial cells in the different phases of the cell cycle was analyzed by flow cytometry. Aplidin analogs were tested in vivo in chicken chorioallantoic membrane (CAM) assays.


RESULTS
Both derivatives inhibited angiogenic capacities of human endothelial cells (HUVECs) in vitro at low nanomolar concentrations. Antiangiogenic effects of both analogs were observed in the CAM. In addition, growth of human multiple myeloma xenografts in vivo in CAM was significantly reduced after application of both analogs. On the molecular level, both derivatives induced cell cycle arrest in G1 phase. This growth arrest of endothelial cells correlated with induction of the cell cycle inhibitor p16(INK4A) and increased senescence-associated beta galactosidase activity. In addition, Aplidin analogs induced oxidative stress and decreased production of the vascular maturation factors Vasohibin-1 and Dickkopf-3.


CONCLUSIONS
From these findings we conclude that both analogs are promising agents for the development of antiangiogenic drugs acting independent on classical inhibition of VEGF signaling.
Department of Internal Medicine V, Innsbruck Medical University, Innrain 66, 6020, Innsbruck, Austria. bojana.borjan@i-med.ac.at.
Bojana
B
Borjan
Department of Internal Medicine V, Innsbruck Medical University, Innrain 66, 6020, Innsbruck, Austria. normann.steiner@i-med.ac.at.
Normann
N
Steiner
Department of Internal Medicine V, Innsbruck Medical University, Innrain 66, 6020, Innsbruck, Austria. silvia.carbon@i-med.ac.at.
Silvia
S
Karbon
Oncotyrol GmbH, Karl Kapfererstrasse 5, 6020, Innsbruck, Austria. johann.kern@oncotyrol.at.
Johann
J
Kern
Pharmamar, R&D Department, Avda de los Reyes 1, 28770, Colmenar Viejo, Madrid, Spain. afrancesch@pharmar.com.
Andrés
A
Francesch
Department of Anesthesiology & Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria. martin.hermann@uki.at.
Martin
M
Hermann
Department of Internal Medicine V, Innsbruck Medical University, Innrain 66, 6020, Innsbruck, Austria. wolfgang.willenbacher@uki.at.
Wolfgang
W
Willenbacher
Department of Internal Medicine V, Innsbruck Medical University, Innrain 66, 6020, Innsbruck, Austria. eberhard.gunsilius@i-med.ac.at.
Eberhard
E
Gunsilius
Department of Internal Medicine V, Innsbruck Medical University, Innrain 66, 6020, Innsbruck, Austria. gerold.untergasser@i-med.ac.at.|Tyrolean Cancer Research Institute, 6020, Innsbruck, Austria. gerold.untergasser@i-med.ac.at.
Gerold
G
Untergasser
D000970:Antineoplastic Agents / Q000494:pharmacology; D015153:Blotting, Western; D000069286:Bortezomib / Q000494:pharmacology*; D002453:Cell Cycle; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D047630:Depsipeptides / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D018613:Microscopy, Confocal; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D018384:Oxidative Stress; D010456:Peptides, Cyclic; D011247:Pregnancy; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D047630:Depsipeptides; D010456:Peptides, Cyclic; D000069286:Bortezomib; C098980:plitidepsin