Partial Characterization of Endothelial FGF Receptor Functional Domain by Monoclonal Antibody VBS-1

Abstract

Polypeptide growth factors mediate their cellular responses by binding to and activating specific cell surface receptors. Monoclonal antibody (MAb) VBS-1, produced against native fibroblast growth factor receptor-1 (FGFR-1), inhibited the binding of fibroblast growth factor-2 (FGF-2) to its receptor on coronary venular endothelial cells (CVECs) as determined by 125I-FGF-2 Scatchard analysis and [3H]thymidine uptake assays (ED50 = 80 ng/mL). Enzyme studies demonstrated that MAb VBS-1 binds to a protein epitope. Proteolytic mapping of the CVEC-FGFR established that a 52 kDa doublet contained the FGF binding site and the MAb VBS-1 antigenic epitope. N-glycanase digestion suggested the presence of a 50 kDa core protein for the CVEC-FGFR. Tunicamycin treatment resulted in the loss of expression of the core protein and the mature receptor, indicating the importance of CVEC-FGFR n-linked glycosylation. By Northern blot analysis, it was determined that CVECs express fgfr-1 and not fgfr-2. VBS-1 recognized FGFR-1 (140 kDa) and crossreacted weakly with FGFR-2 (135 kDa). Using a combination of affinity crosslinking, proteolytic mapping and Mab VBS-1 binding studies, we have located the FGF binding site near the NH2-terminal domain of the receptor close to the highly acidic box.

Lysyl oxidase propeptide inhibits prostate cancer cell growth by mechanisms that target FGF-2-cell binding and signaling

“…This antibody inhibits FGF-2 induced DNA synthesis in coronary venular endothelial cells by blocking FGF-2 binding to its receptor (Blanckaert et al , 2002). DU 145 cells cultured in 0.1% serum were treated with 0 or 10 μg/ml anti-FGFR1 antibody or control IgG for 18 hours.…”

Anti-angiogeneic target therapy for cancer with vaccine based on the recombinant chicken FGFR-1 in tumor-bearing mice

“…Since FGFR-1 is a important regulatory molecule of angiogenesis in solid tumor [4][5][6][7][8] , it is very promising approach for cancer treatment by using blockers of the bFGF/FGFR-1 signal transduction to suppress tumor angiogenesis and tumor growth. So the breaking immune tolerance against FGFR-1 in solid tumors can be used as a new effective approach for cancer treatment of active immunity.…”

“…FGFR-1 is a member of the receptor tyrosine kinase family composed of an ectodomain juxtaposed to a transmembrane domain to the cytoplasmic kinase endodomain. More and more studies demonstrated that FGFR-1 is markedly expressed both in active endothelial cells and in a variety of tumors, which plays an important role in tumor angiogenesis and ZHENG tumor growth [4][5][6][7][8] . Thus, it is reasonable to consider using FGFR-1 as a target of active immunotherapy for tumor treatment, which could suppress angiogenesis and further inhibit tumor growth by blocking the bFGF/FGFR-1 signal transduction.…”