Antiangiogenic Vascular Endothelial Growth Factor-Blocking Peptides Displayed on the Capsid of an Infectious Oncolytic Parvovirus: Assembly and Immune Interactions
Esther Grueso, Cristina Sánchez-Martínez, Tania Calvo-López, Fernando J de Miguel, Noelia Blanco-Menéndez, Marian Fernandez-Estevez, Maria Elizalde, Jorge Sanchez, Omar Kourani, Diana Martin, Aroa Tato, Milagros Guerra, Germán Andrés, José M Almendral
As many tumor cells synthetize vascular endothelial growth factors (VEGF) that promote neo-vascularization and metastasis, frontline cancer therapies often administer anti-VEGF (α-VEGF) antibodies. To target the oncolytic parvovirus minute virus of mice (MVM) to the tumor vasculature, we studied the functional tolerance, evasion of neutralization, and induction of α-VEGF antibodies of chimeric viruses in which the footprint of a neutralizing monoclonal antibody within the 3-fold capsid spike was replaced by VEGF-blocking peptides: P6L (PQPRPL) and A7R (ATWLPPR).
Both peptides allowed viral genome replication and nuclear translocation of chimeric capsid subunits. MVM-P6L efficiently propagated in culture, exposing the heterologous peptide on the capsid surface, and evaded neutralization by the anti-spike monoclonal antibody. In contrast, MVM-A7R yielded low infectious titers and was poorly recognized by an α-A7R monoclonal antibody. MVM-A7R showed a deficient assembly pattern, suggesting that A7R impaired a transitional configuration that the subunits must undergo in the 3-fold axis to close up the capsid shell. The MVM-A7R chimeric virus consistently evolved in culture into a mutant carrying the P6Q amino acid substitution within the A7R sequence, which restored normal capsid assembly and infectivity.
Consistent with this finding, anti-native VEGF antibodies were induced in mice by a single injection of MVM-A7R empty capsids, but not by MVM-A7R virions. This fundamental study provides insights to endow an infectious parvovirus with immune antineovascularization and evasion capacities by replacing an antibody footprint in the capsid 3-fold axis with VEGF-blocking peptides, and it also illustrates the evolutionary capacity of single-stranded DNA (ssDNA) viruses to overcome engineered capsid structural restrictions.
CITATION J Virol. 2019 Sep 12;93(19):e00798-19. doi: 10.1128/JVI.00798-19. Print 2019 Oct 1.