Anti-EGFL7 antibodies enhance stress-induced endothelial cell death and anti-VEGF efficacy
Leisa Johnson, … , Weilan Ye, Priti S. Hegde
Leisa Johnson, … , Weilan Ye, Priti S. Hegde
Published August 15, 2013
Citation Information: J Clin Invest. 2013;123(9):3997-4009. https://doi.org/10.1172/JCI67892.
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Research Article Oncology

Anti-EGFL7 antibodies enhance stress-induced endothelial cell death and anti-VEGF efficacy

Abstract

Many oncology drugs are administered at their maximally tolerated dose without the knowledge of their optimal efficacious dose range. In this study, we describe a multifaceted approach that integrated preclinical and clinical data to identify the optimal dose for an antiangiogenesis agent, anti-EGFL7. EGFL7 is an extracellular matrix–associated protein expressed in activated endothelium. Recombinant EGFL7 protein supported EC adhesion and protected ECs from stress-induced apoptosis. Anti-EGFL7 antibodies inhibited both of these key processes and augmented anti-VEGF–mediated vascular damage in various murine tumor models. In a genetically engineered mouse model of advanced non–small cell lung cancer, we found that anti-EGFL7 enhanced both the progression-free and overall survival benefits derived from anti-VEGF therapy in a dose-dependent manner. In addition, we identified a circulating progenitor cell type that was regulated by EGFL7 and evaluated the response of these cells to anti-EGFL7 treatment in both tumor-bearing mice and cancer patients from a phase I clinical trial. Importantly, these preclinical efficacy and clinical biomarker results enabled rational selection of the anti-EGFL7 dose currently being tested in phase II clinical trials.

Authors

Leisa Johnson, Mahrukh Huseni, Tanya Smyczek, Anthony Lima, Stacey Yeung, Jason H. Cheng, Rafael Molina, David Kan, Ann De Mazière, Judith Klumperman, Ian Kasman, Yin Zhang, Mark S. Dennis, Jeffrey Eastham-Anderson, Adrian M. Jubb, Olivia Hwang, Rupal Desai, Maike Schmidt, Michelle A. Nannini, Kai H. Barck, Richard A.D. Carano, William F. Forrest, Qinghua Song, Daniel S. Chen, Louie Naumovski, Mallika Singh, Weilan Ye, Priti S. Hegde

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Figure 1

Recombinant EGFL7 protein decreases stress-induced EC apoptosis.

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Recombinant EGFL7 protein decreases stress-induced EC apoptosis. Cleaved...
Cleaved caspase-3 and caspase-7 (y axis) activity were measured on HUVECs cultured for 16 hours under the conditions indicated on the x axis. Higher values on the y axis indicate increased EC death. In all panels, filled symbols represent data derived from HUVECs cultured on tissue culture plates coated with EGFL7 protein, whereas open symbols represent data from HUVECs cultured on plates coated with other substances, including culture medium (A), poly-lysine (B), osteopontin (C), and fibronectin (FN) (D–F). Cells were cultured in serum-containing medium with DMSO as the negative control (blue symbols, A–F) or treated with the hypoxic mimetics DFX at 400 μM (red symbols, A–D) or CoCl2 at 200 μM (red symbols, E), or cultured in serum-free medium (red symbols, F), and then assayed for cleaved caspase-3 and caspase-7 normalized to cell counts, where feasible (A–D and F; see Methods). HUVEC apoptosis assay was also carried out as described above in the presence of a control antibody or the humanized anti-EGFL7 antibody, h18F7 (G). While EGFL7 or a mixture of EGFL7 with fibronectin reduced DFX-induced apoptosis, anti-EGFL7 abolished the activity of the EGFL7 protein. Each symbol represents 2 to 5 independent measurements; the mean ± the SEM is depicted. P values were calculated by unpaired, 2-tailed Student’s t test. *P < 0.05; **P < 0.005; ***P < 0.0005.