Expression and in vivo localization of VEGFR-2 in tumor bearing mice detected by radiolabeled monoclonal antibodies

GABRIEL L. FISZMAN; ERNESTO G. D’ORIO; ADRIÁN GÓNGORA; ALEJANDRO MLADOVAN; MARÍA A. JASNIS; ALBERTO BALDI

Genoma Science and Molecular Medicine. Ed. Bioscience Publication. New Delhi. India

Lugar: New Delhi; Año: 2007;

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor, playing a central role in tumor neovascularization; its receptor VEGFR-2 (KDR in humans /flk1 in mice) is over-expressed in vascular endothelial and tumor cells of the majority of animal and human tumors. We produced a monoclonal antibody (Mab) to VEGFR-2 using as immunogen the extracellular domain of recombinant KDR expressed in mammalian cells as a fusion protein with Fc-IgG. Hybridomas were screened by solid phase ELISA, cell-ELISA and cell proliferation assay with human umbilical vein endothelial cells (HUVEC). These procedures allowed us to isolate a Mab able to bind VEGFR-2 but unable to inhibit VEGF activity. Mabs labeled with 131I were i.p. injected into Balb/c mice bearing syngeneic mammary adenocarcinoma LM3 and nude mice bearing xenogeneic human colon adenocarcinoma HT29. Scintigraphy images showed optimal tumor-background Mab uptake ratio vs normal mouse 131I-IgG (NIgG). Biodistribution, expressed as % of injected dose/tissue gram, showed significantly higher Mab uptake than NIgG in the tumor tissue. Levels of radiotracer in all normal tissues were less than in tumors at different times after Mab injection. We can conclude that Mabs against VEGFR-2 might be very useful and specific tracers for in vivo tumor detection and eventually for metastasis localization. 131I were i.p. injected into Balb/c mice bearing syngeneic mammary adenocarcinoma LM3 and nude mice bearing xenogeneic human colon adenocarcinoma HT29. Scintigraphy images showed optimal tumor-background Mab uptake ratio vs normal mouse 131I-IgG (NIgG). Biodistribution, expressed as % of injected dose/tissue gram, showed significantly higher Mab uptake than NIgG in the tumor tissue. Levels of radiotracer in all normal tissues were less than in tumors at different times after Mab injection. We can conclude that Mabs against VEGFR-2 might be very useful and specific tracers for in vivo tumor detection and eventually for metastasis localization.