Characterization of Morreton Virus (MORV) as a Novel Oncolytic Virotherapy Platform for Liver Cancers

Morreton virus (MORV) is a novel oncolytic Vesiculovirus, genetically distinct from vesicular stomatitis virus (VSV). we report that MORV induced potent cytopathic effects in a panel of cholangiocarcinoma (CCA) and hepatocellular carcinoma (HCC) cell lines. In addition, high intranasal doses of MORV were not associated with significant adverse effects and were well tolerated in mice bearing liver tumor xenografts and syngeneic liver cancers. Furthermore, single intratumoral treatments with MORV (1 x 107 TCID50) triggered a robust antitumor immune response leading to substantial tumor regression and disease control in a syngeneic CCA model, using 10-fold lower dose compared to VSV (1 x 108 TCID50). In addition, MORV and VSV both induced prominent tumor growth delay in immunodeficient mice bearing Hep3B hepatocellular carcinoma (HCC) but not in mice bearing HuCCT-1 CCA xenografts. Our findings indicate that wild-type MORV is safe and can induce potent tumor regression in HCC and CCA animal models without adverse events via immune-mediated and immune-independent mechanisms. Further development and clinical translation of MORV as virotherapy for liver cancers are warranted.