Bevacizumab suppression of establishment of micrometastases in experimental ocular melanoma.
OBJECTIVE
This study was undertaken to determine whether anti-vascular endothelial growth factor (VEGF) therapy inhibits growth of primary uveal melanoma and spread of its hepatic micrometastases.


METHODS
The human uveal melanoma cell lines Mel290 and Mel 270, HUVECs, mouse B16LS9 melanoma cells, and mouse vascular endothelial cells were separately cultured or co-cultured and incubated with bevacizumab or IgG1. The level of VEGF protein in the culture medium was measured by ELISA. In vitro angiogenesis and invasion assays were performed under bevacizumab or IgG1 treatment. Mel290 or B16LS9 cells were inoculated into NU/NU or C57Bl/6 mouse eyes which were enucleated after 7 days. The sizes of the intraocular tumors were determined. Time and dosage experiments were performed by using 50 or 250 microg bevacizumab starting at day 1 or 4 after inoculation. Hepatic micrometastases were enumerated. Proliferation, apoptosis, and angiogenesis markers were detected in the ocular tumor by immunofluorescence staining.


RESULTS
Bevacizumab significantly reduced the level of VEGF in the culture media from human uveal melanoma cells, mouse melanoma cells, and co-cultured cells. It also inhibited cell tube formation and decreased in vitro invasion of tumor cells. In the mouse model, bevacizumab suppressed primary ocular melanoma growth and the formation of hepatic micrometastases in a dose-dependent manner. Furthermore, immunohistochemical staining showed decreased Ki67 and unchanged caspase 3 expression after treatment with bevacizumab.


CONCLUSIONS
Treatment with bevacizumab suppressed in vitro growth and in vivo hepatic micrometastasis of ocular melanoma cells. Bevacizumab is a potential therapeutic agent for the treatment of uveal melanoma micrometastases.
Yang
Hua
H
Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, USA.
Jager
Martine J
MJ
Grossniklaus
Hans E
HE
D020533:Angiogenesis Inhibitors / Q000627:therapeutic use*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D017209:Apoptosis; D000068258:Bevacizumab; D053148:Caspase 3 / Q000378:metabolism; D049109:Cell Proliferation; D018920:Coculture Techniques; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008113:Liver Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000556:secondary; D008546:Melanoma, Experimental / Q000098:blood supply / Q000188:drug therapy* / Q000556:secondary; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000188:drug therapy* / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014604:Uveal Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors* / Q000378:metabolism
D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D019394:Ki-67 Antigen; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab; D053148:Caspase 3