title: An in vivo antilymphatic screen in zebrafish identifies novel inhibitors of mammalian lymphangiogenesis and lymphatic-mediated metastasis.
abstract: The growth of new lymphatic vessels (lymphangiogenesis) in tumors is an integral step in the metastatic spread of tumor cells, first to the sentinel lymph nodes that surround the tumor and then elsewhere in the body. Currently, no selective agents designed to prevent lymphatic vessel growth have been approved for clinical use, and there is an important potential clinical niche for antilymphangiogenic agents. Using a zebrafish phenotype-based chemical screen, we have identified drug compounds, previously approved for human use, that have antilymphatic activity. These include kaempferol, a natural product found in plants; leflunomide, an inhibitor of pyrimidine biosynthesis; and cinnarizine and flunarizine, members of the type IV class of calcium channel antagonists. Antilymphatic activity was confirmed in a murine in vivo lymphangiogenesis Matrigel plug assay, in which kaempferol, leflunomide, and flunarizine prevented lymphatic growth. We show that kaempferol is a novel inhibitor of VEGFR2/3 kinase activity and is able to reduce the density of tumor-associated lymphatic vessels as well as the incidence of lymph node metastases in a metastatic breast cancer xenograft model. However, in this model, kaempferol administration was also associated with tumor deposits in the pancreas and diaphragm, and flunarizine was found to be tumorigenic. Although this screen revealed that zebrafish is a viable platform for the identification and development of mammalian antilymphatic compounds, it also highlights the need for focused secondary screens to ensure appropriate efficacy of hits in a tumor context.
authors: Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand.
authors: Jonathan W
authors: JW
authors: Astin
authors: Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Auckland, New Zealand. Maurice Wilkins Centre for Molecular Biodiscovery, School of Biological Sciences, University of Auckland, Auckland, New Zealand.
authors: Stephen M F
authors: SM
authors: Jamieson
authors: Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand. Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Auckland, New Zealand.
authors: Tiffany C Y
authors: TC
authors: Eng
authors: Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand.
authors: Maria V
authors: MV
authors: Flores
authors: Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand.
authors: June P
authors: JP
authors: Misa
authors: Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand.
authors: Annie
authors: A
authors: Chien
authors: Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand. Maurice Wilkins Centre for Molecular Biodiscovery, School of Biological Sciences, University of Auckland, Auckland, New Zealand.
authors: Kathryn E
authors: KE
authors: Crosier
authors: Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand. Maurice Wilkins Centre for Molecular Biodiscovery, School of Biological Sciences, University of Auckland, Auckland, New Zealand. ps.crosier@auckland.ac.nz.
authors: Philip S
authors: PS
authors: Crosier
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002936:Cinnarizine / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects / Q000473:pathology; D005260:Female; D005444:Flunarizine / Q000494:pharmacology; D006801:Humans; D007555:Isoxazoles / Q000494:pharmacology; D044949:Kaempferols / Q000494:pharmacology; D000077339:Leflunomide; D008198:Lymph Nodes / Q000187:drug effects* / Q000473:pathology*; D042583:Lymphangiogenesis / Q000187:drug effects*; D008207:Lymphatic Metastasis; D051379:Mice; D008810:Mice, Inbred C57BL; D009369:Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D011897:Random Allocation; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D015027:Zebrafish
chemical_list: D000970:Antineoplastic Agents; D007555:Isoxazoles; D044949:Kaempferols; D002936:Cinnarizine; C006552:kaempferol; D020794:Receptor Protein-Tyrosine Kinases; D000077339:Leflunomide; D005444:Flunarizine