(169f) Utilizing an Integrated Experimental and in silico Approach to Engineer Cross Reactive Antibodies Against VEGFA and PlGF2 in Pediatric Glioblastoma

Pediatric glioblastoma is characterized by the overexpression of growth factors that target angiogenic pathways in tumors, presenting a unique opportunity for therapeutic design. In healthy cells, Vascular Endothelial Growth Factor-A (VEGFA) contributes to vascular permeability and angiogenesis, but overexpression in cancers is known to contribute to tumor angiogenesis. Meanwhile, Placental Growth Factor 2 (PlGF2) plays a similar role in placental angiogenesis and vascular development, but is also upregulated across many cancer types. Though progress has been made to design antibodies to block VEGFA interactions with its family of Vascular Endothelial Growth Factor Receptors (VEGFRs) and its co-receptor, Neuropilin 1 (NRP1), the introduction of anti-VEGFA antibodies can lead to therapeutic escape by expressing related PlGF2. Critically, sequence identity between growth factors can be leveraged to design cross-reactive antibodies to simultaneously target VEGFA and PlGF2 and their interactions with NRP1 and VEGFR1, presenting opportunities to improve specificity and versatility in vivo and expand clinical translatability. To this end, our experimental collaborators recently determined a suite of novel candidate antibodies and measured their affinity and specificity/cross-reactivity for VEGFA, PlGF2, and antibody-growth factor complexes with NRP1, VEGFR1, and heparin sulfates. This poster will describe our use of computational approaches, including static docking and molecular dynamics simulations, to elucidate the molecular-level interactions between the relevant growth factors and newly-derived antibodies. Additionally, it will highlight our efforts to identify the molecular basis for the apparent cross-reactivity of these antibodies, via assessing the effects of single point mutations introduced into the antibody sequences in silico. Finally, we describe our efforts to quantify competition between the growth factors and antibodies in the presence and absence of NRP1 and VEGFR1. Overall, characterization of this antibody suite informs angiogenic interactions between VEGFA and PlGF2 signaling in pediatric glioblastoma, leveraging in silico approaches to advance efforts toward robust and translatable cancer therapeutics.