title: Inhibition of c-Met reduces lymphatic metastasis in RIP-Tag2 transgenic mice.
abstract: Inhibition of VEGF signaling can promote lymph node metastasis in preclinical models, but the mechanism is not fully understood, and successful methods of prevention have not been found. Signaling of hepatocyte growth factor (HGF) and its receptor c-Met can promote the growth of lymphatics and metastasis of some tumors. We sought to explore the contributions of c-Met signaling to lymph node metastasis after inhibition of VEGF signaling. In particular, we examined whether c-Met is upregulated in lymphatics in or near pancreatic neuroendocrine tumors in RIP-Tag2 transgenic mice and whether lymph node metastasis can be reduced by concurrent inhibition of VEGF and c-Met signaling. Inhibition of VEGF signaling by anti-VEGF antibody or sunitinib in mice from the age of 14 to 17 weeks was accompanied by more intratumoral lymphatics, more tumor cells inside lymphatics, and more lymph node metastases. Under these conditions, lymphatic endothelial cells, like tumor cells, had strong immunoreactivity for c-Met and phospho-c-Met. c-Met blockade by the selective inhibitor, PF-04217903, significantly reduced metastasis to local lymph nodes. Together, these results indicate that inhibition of VEGF signaling in RIP-Tag2 mice upregulates c-Met expression in lymphatic endothelial cells, increases the number of intratumoral lymphatics and number of tumor cells within lymphatics, and promotes metastasis to local lymph nodes. Prevention of lymph node metastasis by PF-04217903 in this setting implicates c-Met signaling in tumor cell spread to lymph nodes.
authors.affiliation: Department of Anatomy, Comprehensive Cancer Center, Cardiovascular Research Institute, University of California-San Francisco, San Francisco, CA 94143, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Sennino
authors.forename: Toshina
authors.initials: T
authors.lastname: Ishiguro-Oonuma
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Schriver
authors.forename: James G
authors.initials: JG
authors.lastname: Christensen
authors.forename: Donald M
authors.initials: DM
authors.lastname: McDonald
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D007150:Immunohistochemistry; D007211:Indoles / Q000494:pharmacology; D008207:Lymphatic Metastasis; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D010766:Phosphorylation / Q000187:drug effects; D019859:Proto-Oncogene Proteins c-met / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011719:Pyrazines / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D000077210:Sunitinib; D014230:Triazoles / Q000494:pharmacology*; D042582:Vascular Endothelial Growth Factor C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology
chemical_list: C558663:2-(4-(3-quinolin-6-ylmethyl-3H-(1,2,3)triazolo(4,5-b)pyrazin-5-yl)pyrazol-1-yl)ethanol; D000906:Antibodies; D000970:Antineoplastic Agents; D007211:Indoles; D011719:Pyrazines; D011758:Pyrroles; D014230:Triazoles; D042582:Vascular Endothelial Growth Factor C; D019859:Proto-Oncogene Proteins c-met; D000077210:Sunitinib