Oncolytic Virus Therapy with HSV-1 for Hematological Malignancies

Oncolytic herpes simplex virus type 1 (HSV-1) has been investigated to expand its application to various malignancies. Because hematopoietic cells are resistant to HSV-1, its application to hematological malignancies has been rare. Here, we show that the third generation oncolytic HSV-1, T-01, infected and killed 18 of 26 human cell lines and 8 of 15 primary cells derived from various lineages of hematological malignancies. T-01 replicated at low levels in the cell lines. Viral entry and the oncolytic effect were positively correlated with the expression level of nectin-1 and to a lesser extent 3-O-sulfated heparan sulfate, receptors for glycoprotein D of HSV-1, on tumor cells. Transfection of nectin-1 into nectin-1-negative tumor cells made them susceptible to T-01. The oncolytic effects did not appear to correlate with the expression or phosphorylation of antiviral molecules in the cyclic GMP-AMP (cGAS)-stimulator of interferon genes (STING) and PKR-eIF2α pathways. In an immunocompetent mouse model, intratumoral injection of T-01 into lymphoma induced regression of injected, as well as non-injected, contralateral tumors accompanied by abundant infiltration of antigen-specific CD8⁺ T cells. These data suggest that intratumoral injection of oncolytic HSV-1 may be applicable to systemic hematological malignancies. Nectin-1 expression may be the most useful biomarker for optimal efficacy.