National Institutes of Health/National Cancer Institute (NIH/NCI)
P30 CA015704-40
United States
Norwegian Research Council
245828
Norway
Citation
Journal: bioRxiv / Year: 2025 Title: Shared ligand-blocking mechanism but distinct conformational modulation by α5-targeting antibodies BIIG2 and MINT1526A. Authors: Adam Nguyen / Joel B Heim / Gabriele Cordara / Matthew C Chan / Hedda Johannesen / Cristine Charlesworth / Ming Li / Caleigh M Azumaya / Benjamin Madden / Ute Krengel / Alexander Meves / Melody G Campbell / Abstract: Integrins are heterodimeric receptors important for cell adhesion and signaling. Integrin α5β1 is a key mediator of angiogenesis and its dysregulation is associated with tumor progression and ...Integrins are heterodimeric receptors important for cell adhesion and signaling. Integrin α5β1 is a key mediator of angiogenesis and its dysregulation is associated with tumor progression and metastasis. Despite numerous efforts, α5β1-targeting therapeutics have been unsuccessful due to poor efficacy and off-target effects. A contributing factor is our limited understanding of how integrin conformation influences interactions with therapeutics. Using cell-based functional assays, patient derived xenografts, biophysics, and electron microscopy, we shed light on these relationships by characterizing two anti-α5β1 antibodies, BIIG2 and MINT1526A. We show that both antibodies bind α5β1 with nanomolar affinity, reduce angiogenesis , and bind overlapping epitopes that block fibronectin binding. However, using cryoEM, we reveal that while BIIG2 binding doesn't alter the conformational states, MINT1526A restricts α5β1's range of flexibility. These insights can guide which aspects to prioritize and improve the design of future integrin-targeted therapeutics.
Mass: 23740.486 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Details: N-terminal glutamine modified to a pyroglutamate proline 100C (Kabat numbering) modified to 5-hydroxyproline Source: (gene. exp.) Rattus norvegicus (Norway rat) / Production host: Homo sapiens (human)
#2: Antibody
BIIG2Fab, lightchain
Mass: 23478.137 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Details: lysine 199 modified to methyllysine / Source: (gene. exp.) Rattus norvegicus (Norway rat) / Production host: Homo sapiens (human)
Mass: 18.015 Da / Num. of mol.: 224 / Source method: isolated from a natural source / Formula: H2O
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Details
Has ligand of interest
N
Has protein modification
Y
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Experimental details
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Experiment
Experiment
Method: X-RAY DIFFRACTION / Number of used crystals: 1
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Sample preparation
Crystal
Density Matthews: 2.4 Å3/Da / Density % sol: 48.8 % / Description: prism
Crystal grow
Temperature: 293.15 K / Method: vapor diffusion, sitting drop Details: crystallization solution: of 20% w/v PEG 3350, 0.2 M sodium chloride, 2.5% v/v DMSO protein buffer solution: 25 mM Bis-Tris-HCl, approx. 130 mM NaCl at pH 6.5
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Data collection
Diffraction
Mean temperature: 100 K / Serial crystal experiment: N
Diffraction source
Source: SYNCHROTRON / Site: MAX IV / Beamline: BioMAX / Wavelength: 0.95372 Å