Ad5{{sub}}NULL{{/sub}}-A20: A Tropism-Modified, αvβ6 Integrin-Selective Oncolytic Adenovirus for Epithelial Ovarian Cancer Therapies.

Virotherapies are maturing in the clinical setting. Adenoviruses (Ad) are excellent vectors for the manipulability and tolerance of transgenes. Poor tumor selectivity, off-target sequestration, and immune inactivation hamper clinical efficacy. We sought to completely redesign Ad5 into a refined, tumor-selective virotherapy targeted to αvβ6 integrin, which is expressed in a range of aggressively transformed epithelial cancers but nondetectable in healthy tissues. Ad5{{sub}}NULL{{/sub}}-A20 harbors mutations in each major capsid protein to preclude uptake via all native pathways. Tumor-tropism via αvβ6 targeting was achieved by genetic insertion of A20 peptide (NAVPNLRGDLQVLAQKVART) within the fiber knob protein. The vector's selectivity and was assessed. The tropism-ablating triple mutation completely blocked all native cell entry pathways of Ad5{{sub}}NULL{{/sub}}-A20 via coxsackie and adenovirus receptor (CAR), αvβ3/5 integrins, and coagulation factor 10 (FX). Ad5{{sub}}NULL{{/sub}}-A20 efficiently and selectively transduced αvβ6{{sup}}+{{/sup}} cell lines and primary clinical ascites-derived EOC , including in the presence of preexisting anti-Ad5 immunity. biodistribution of Ad5{{sub}}NULL{{/sub}}-A20 following systemic delivery in non-tumor-bearing mice was significantly reduced in all off-target organs, including a remarkable 10{{sup}}7{{/sup}}-fold reduced genome accumulation in the liver compared with Ad5. Tumor uptake, transgene expression, and efficacy were confirmed in a peritoneal SKOV3 xenograft model of human EOC, where oncolytic Ad5{{sub}}NULL{{/sub}}-A20-treated animals demonstrated significantly improved survival compared with those treated with oncolytic Ad5. Oncolytic Ad5{{sub}}NULL{{/sub}}-A20 virotherapies represent an excellent vector for local and systemic targeting of αvβ6-overexpressing cancers and exciting platforms for tumor-selective overexpression of therapeutic anticancer modalities, including immune checkpoint inhibitors. .