Angiopoietin-2 inhibition using siRNA or the peptide antagonist L1-10 results in antitumor activity in human neuroblastoma.
OBJECTIVE
The angiopoietin/Tie-2 system has been identified as a key role player in tumor angiogenesis. We investigated whether angiopoietin-2 could be a promising target in human neuroblastoma.


METHODS
Angiopoietin-2 down-regulation by siRNA or shRNA was evaluated in vitro in Kelly cells. Angiopoietin-2 shRNA-transfected Kelly cells were tested in a chorioallantoic membrane (CAM) assay to evaluate tumor growth and microvessel density. The effects of L1-10, a peptide-Fc fusion molecule blocking angiopoietin-2/Tie-2 interaction, administered 3 times/week were assessed in a murine neuroblastoma xenograft model.


RESULTS
Angiopoietin-2 down-regulation by siRNA or shRNA in Kelly cells inhibited cell proliferation and migration. In vivo growth and microvessel density of angiopoietin-2 shRNA-transfected Kelly cells in the CAM assay were reduced. Therapy of advanced tumors with L1-10 did not stop tumor progression. However, starting L1-10 treatment at the same time as neuroblastoma cell injection significantly inhibited tumor growth (vehicule: 903 ± 160 mm(3); L1-10: 270 ± 152 mm(3) after 26 days; P < 0.05). Microvessel density was reduced in both L1-10-treated tumors, whereas expression of angiopoietin-2 and VEGF-A did not change.


CONCLUSIONS
This first demonstration of beneficial angiopoietin-2 inhibition in neuroblastoma offers an additional approach for future therapy strategies, especially by using L1-10 in the setting of minimal residual disease.
Clinic IV: Pediatric Hematology and Oncology, Center of Pediatrics and Adolescent Medicine, University Medical Hospital, Mathildenstrasse 1, 79106, Freiburg, Germany.
Saritha Sandra
SS
D'Souza
Karine
K
Scherzinger-Laude
Marc
M
Simon
Bharathi P
BP
Salimath
Jochen
J
Rössler
D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D042702:Angiopoietin-2 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D005260:Female; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D055806:Microvessels / Q000187:drug effects / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D009447:Neuroblastoma / Q000098:blood supply / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D010455:Peptides / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology*; D011961:Receptors, Fc / Q000235:genetics / Q000627:therapeutic use; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
D020533:Angiogenesis Inhibitors; D042702:Angiopoietin-2; D010455:Peptides; D034741:RNA, Small Interfering; D011961:Receptors, Fc; D011993:Recombinant Fusion Proteins; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A