Tumor accumulation of radiolabeled bevacizumab due to targeting of cell- and matrix-associated VEGF-A isoforms.

PURPOSE Vascular endothelial growth factor-A (VEGF-A) is one of the most important factors inducing angiogenesis in tumors. Nine splice-variant isoforms of VEGF-A have been identified, each having different properties. Recently, we showed that radiolabeled anti-VEGF monoclonal antibody, bevacizumab, accumulates specifically in VEGF-A expressing tumors. In this study, we investigated in a nude mouse model which VEGF-isoforms are responsible for tumor accretion. MATERIALS AND METHODS The humanized anti-VEGF-A antibody, A.4.6.1. (bevacizumab), was radiolabeled with In-111. The originally VEGF-negative Mel57 tumor was transfected with different VEGF isoforms (VEGF-121, VEGF-165, and VEGF-189). The obtained melanoma xenografts specifically expressing different VEGF-isoforms were used in mice. The bevacizumab uptake was examined in biodistribution studies and by gamma-camera imaging. RESULTS The tumor cell line expressing VEGF-121 did not show specific uptake, most likely as a result of the fact that this isoform is freely diffusible. Tumors expressing VEGF-165 and -189 were clearly visualized by using gamma-camera imaging. CONCLUSION The accumulation of radiolabeled bevacizumab in the tumor is due to interaction with VEGF-A isoforms that are associated with the tumor cell surface and/or the extracellular matrix. Scintigraphic imaging of the expression of these VEGF isoforms may thus be useful to predict response to angiogenic therapy.

[1]  E. van Marck,et al.  Liver metastases from colorectal adenocarcinomas grow in three patterns with different angiogenesis and desmoplasia , 2001, The Journal of pathology.

[2]  Napoleone Ferrara,et al.  Vascular endothelial growth factor: basic science and clinical progress. , 2004, Endocrine reviews.

[3]  P. Wesseling,et al.  Vascular endothelial growth factor-A(165) induces progression of melanoma brain metastases without induction of sprouting angiogenesis. , 2002, Cancer research.

[4]  H. Hollema,et al.  In Vivo VEGF Imaging with Radiolabeled Bevacizumab in a Human Ovarian Tumor Xenograft , 2007, Journal of Nuclear Medicine.

[5]  M. Rocchi,et al.  Assignment of the vascular endothelial growth factor gene to human chromosome 6p21.3. , 1996, Circulation.

[6]  N. Ferrara,et al.  Vascular endothelial growth factor and the regulation of angiogenesis. , 2000, Recent progress in hormone research.

[7]  J. Park,et al.  The vascular endothelial growth factor (VEGF) isoforms: differential deposition into the subepithelial extracellular matrix and bioactivity of extracellular matrix-bound VEGF. , 1993, Molecular biology of the cell.

[8]  I. Clemmensen,et al.  Angiogenic balance in human melanoma: Expression of VEGF, bFGF, IL‐8, PDGF and angiostatin in relation to vascular density of xenografts in vivo , 2000, International journal of cancer.

[9]  J. Winer,et al.  Dual regulation of vascular endothelial growth factor bioavailability by genetic and proteolytic mechanisms. , 1992, The Journal of biological chemistry.

[10]  P. Tyagi Bevacizumab, when added to paclitaxel/carboplatin, prolongs survival in previously untreated patients with advanced non-small-cell lung cancer: preliminary results from the ECOG 4599 trial. , 2005, Clinical lung cancer.

[11]  Kenneth J. Hillan,et al.  Heterozygous embryonic lethality induced by targeted inactivation of the VEGF gene , 1996, Nature.

[12]  C. Sweep,et al.  EORTC Receptor and Biomarker Study Group Report: A Sandwich Enzyme-Linked Immunosorbent Assay for Vascular Endothelial Growth Factor in Blood and Tumor Tissue Extracts , 2000, The International journal of biological markers.

[13]  Bart Landuyt,et al.  Vascular Endothelial Growth Factor and Angiogenesis , 2004, Pharmacological Reviews.

[14]  A. Heerschap,et al.  Differential effects of vascular endothelial growth factor A isoforms in a mouse brain metastasis model of human melanoma. , 2003, Cancer research.

[15]  J. Fiddes,et al.  The human gene for vascular endothelial growth factor. Multiple protein forms are encoded through alternative exon splicing. , 1991, The Journal of biological chemistry.

[16]  Aleksander S. Popel,et al.  Formation of VEGF isoform-specific spatial distributions governing angiogenesis: computational analysis , 2011, BMC Systems Biology.

[17]  Kenneth J. Hillan,et al.  Discovery and development of bevacizumab, an anti-VEGF antibody for treating cancer , 2004, Nature Reviews Drug Discovery.

[18]  M. Ultsch,et al.  Structure-Function Studies of Two Synthetic Anti-vascular Endothelial Growth Factor Fabs and Comparison with the Avastin™ Fab* , 2006, Journal of Biological Chemistry.

[19]  Jamal Zweit,et al.  Molecular imaging and biological evaluation of HuMV833 anti-VEGF antibody: implications for trial design of antiangiogenic antibodies. , 2002, Journal of the National Cancer Institute.

[20]  Ralph Weissleder,et al.  Quantitating Antibody Uptake In Vivo: Conditional Dependence on Antigen Expression Levels , 2011, Molecular Imaging and Biology.

[21]  W. Oyen,et al.  Optimization of radioimmunotherapy of renal cell carcinoma: labeling of monoclonal antibody cG250 with 131I, 90Y, 177Lu, or 186Re. , 2004, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[22]  T. Nayak,et al.  PET imaging of tumor angiogenesis in mice with VEGF‐A–targeted 86Y‐CHX‐A″‐DTPA‐bevacizumab , 2011, International journal of cancer.

[23]  R. B. Campbell,et al.  Conjugation of bevacizumab to cationic liposomes enhances their tumor-targeting potential. , 2010, Nanomedicine.

[24]  J. A. van der Laak,et al.  Development of the tumor vascular bed in response to hypoxia‐induced VEGF‐A differs from that in tumors with constitutive VEGF‐A expression , 2006, International journal of cancer.

[25]  P. Wesseling,et al.  Micronodular transformation as a novel mechanism of VEGF-A-induced metastasis , 2007, Oncogene.

[26]  H. Hollema,et al.  VEGF-SPECT with ¹¹¹In-bevacizumab in stage III/IV melanoma patients. , 2010, European journal of cancer.

[27]  G. Nikiforidis,et al.  In vivo small animal imaging: current status and future prospects. , 2010, Medical physics.

[28]  W. Oyen,et al.  Specific imaging of VEGF‐A expression with radiolabeled anti‐VEGF monoclonal antibody , 2008, International journal of cancer.

[29]  Leonard,et al.  Humanization of an anti-vascular endothelial growth factor monoclonal antibody for the therapy of solid tumors and other disorders. , 1997, Cancer research.