P3.01-83 Use of Blood Outgrowth Endothelial Cells as a Cellular Carrier for Oncolytic Vesicular Stomatitis Virus in Preclinical Models of NSCLC

Abstract

Oncolytic virus therapy has demonstrated efficacy in numerous tumor models including non-small cell lung cancer. One of the limitations of viral therapy for metastatic lung cancer is that systemic administration can be hindered by complement and antiviral immunity. Thus, we investigated the possibility of using ex-vivo infected blood outgrowth endothelial cells with tumor-homing properties to deliver oncolytic VSV-IFNβ in preclinical models of NSCLC. BOECs were obtained from either human donors or C57/Bl6 mice. Cells were confirmed to maintain the BOEC phenotype and growth characteristics. Indiana strains of VSV were engineered to produce GFP or IFNβ and were titered on Vero cells using either plaque assay or limiting dilution assay. Human NSCLC cell lines, H2009 and H2030 were used for in vitro assays. A549 expressing firefly luciferase cells were used to induce lung metastasis in NOD/SCID mice and treated with BOECs, VSV-IFNβ, or BOECs-infected with VSV-IFNβ. Additionally, syngeneic murine adenocarcinoma cell line, LM2 was used in vivo in A/J mice (n=5). BOEC cells were able to home to metastatic LM2 lung tumors and were retained there for up to 72 hours post-infusion. BOEC cells were retained within lung tumors of mice bearing tumors, but there were none detected in lungs of mice without lung tumors. Both human and murine BOECs could be infected and lysed by VSV-GFP and VSV-IFNβ, however, VSV-IFNβ was attenuated compared to VSV-GFP. Maximal viral titer was obtained at 24 or 48 hours for VSV-GFP and VSV-IFNβ, respectively. Co-culture experiments showed near complete lysis of H2009 cells using infected BOECs. Both H2009 and H2030 cells were lysed efficiently by infected BOECs while naked VSV was completely inhibited in the presence anti-VSV neutralizing antibodies. Using Firefly luciferase-expressing A549 cells, metastatic lung tumors were induced in NOD/SCID mice. Compared to BOEC alone and PBS-treated mice, VSV-IFNβ-infected BOECs resulted in superior antitumor efficacy as measured by luciferase activity (p<0.02). Infected BOECs resulted in superior survival of mice compared to VSV-IFNβ alone (n=10, p<0.05). Using immune competent A/J mice, infected BOECs trended toward improved antitumor efficacy to BOEC alone and intravenous VSV-IFNβ treatment (n=5, p=0.09). Replicating virus was recovered only from lungs of infected BOEC treated mice. BOECs can be used as cellular carrier for systemic delivery of oncolytic VSV-IFNβ. For clinical translation, the use of cellular carriers might be an effective method of virotherapy for metastatic NSCLC.