Development of a low-seroprevalence, αvβ6 integrin-selective virotherapy based on human adenovirus type 10
Abstract
Oncolytic virotherapies (OV) hold immense clinical potential. OV based on human adenoviruses (HAdV) derived from HAdV with naturally low rates of pre-existing immunity will be beneficial for future clinical translation.
We generated a low-seroprevalence HAdV-D10 serotype vector incorporating an αvβ6 integrin-selective peptide, A20, to target alpha v beta 6 -posi-tive tumor cell types. HAdV-D10 has limited natural tropism.
Structural and biological studies of HAdV-D10 knob protein highlighted low-affinity engagement with native adenoviral receptors CAR and sialic acid. HAdV-D10 fails to engage blood coagulation factor X, potentially eliminating "off-target" hepatic sequestration in vivo.
We engineered an A20 peptide that selectively binds αvβ6 integrin into the DG loop of HAdV-D10 fiber knob. Assays in alpha v beta 6+ cancer cell lines demonstrated significantly increased transduction mediated by alpha c beta 6 -targeted variants compared with controls, confirmed microscopically.
HAdV-D10.A20 resisted neutralization by neutralizing HAdV-C5 sera. Systemic delivery of HAdVD10.A20 resulted in significantly increased GFP expression in BT20 tumors.
Replication-competent HAdV-D10.A20 demonstrated αvβ6 integrin-selective cell killing in vitro and in vivo. HAdV-D10 possesses characteristics of a promising virotherapy, combining low seroprevalence, weak receptor interactions, and reduced off-target uptake.
Incorporation of an αvβ6 integrin-selective peptide resulted in HAdVD10.A20, with significant potential for clinical translation.