Abstract 688: Oncolytic VSV with retargeted glycoprotein and genetic ON switch for precise targeting of liver cancer using a synthetic virology platform
Authors: Moles Chad , Basu Rupsa , Flaat Taylor , Collado Christopher , Weijmarshausen Peter 
Published: April 2023

Introduction: Humane Genomics has developed a platform to make artificial oncolytic viruses with unprecedented selectivity and efficiency. The platform is based on Vesicular Stomatitis Virus (VSV), which has several ideal properties (highly oncolytic, non-pathogenic, small genome that’s well understood and easily modified). Here we present the development of HG001, our first therapy for the treatment of liver cancer.

Methods: Genome design of HG001 was completed using our proprietary software. The virus was designed with a GPC3 targeting glycoprotein and a genetic ON-switch (aptazyme) with a liver cancer specific aptamer. DNA fragments were synthesized and then assembled to construct the complete viral genome of HG001. Virus was rescued in BHK-21 using reverse genetics and then verified by nanopore sequencing. We evaluated efficacy and safety in cancer- (Huh-7, SNU-449) and healthy- (NIH/3T3) cells. VSV wildtype was used as a control virus. IncuCyte live cell imaging and analysis software was used to quantify efficacy and safety. Cell counts and cell area per well (µm2/well) were measured to evaluate cell health and proliferation. Apoptosis was determined using Annexin V. Student’s t-test was used to assess statistical significance.

Results: Our platform enabled us to complete the process from assembly of the fragments to the start of testing of HG001 in under 2 weeks. To determine selectivity and efficacy, we evaluated serial dilutions in Huh7 (high expression of GPC3) and SNU-449 cells (GPC3 negative). Real time monitoring of HG001 showed cell killing in Huh7 cells at MOI=1 (p&lt;0.001) and cytopathic effects (CPE) in MOI=0.1. However, no impact on cell proliferation and viability was found in SNU-449 (p=ns), indicating specificity for the target receptor. To further validate selectivity and demonstrate safety, we assayed normal NIH/3T3 cells with the same titers. We did not observe any indication of cytotoxicity, and kinetic data of cell growth revealed no significant difference between HG001 and mock infection (p=ns). In stark contrast, VSV-WT induced rapid lysis in NIH/3T3 cells at MOI=0.01 (p&lt;0.01). Taken together, HG001 exhibits at least 2 orders of magnitude improvement in safety. Apoptosis assays conducted in these cell lines corroborated these findings. HG001 was well tolerated and showed no adverse effects during initial in vivo studies. Current in vivo studies are ongoing to confirm efficacy.

Conclusion: We have shown that a rationally designed synthetic virus can be made efficiently with high specificity and efficacy. Initial testing is showing high promise for future in vivo testing. With further iterations we hope to develop a strong therapeutic for liver cancer. Going forward, we are actively looking for collaborations with oncology centers on other types of cancer we could target using our platform.

Citation Format: Chad Moles, Rupsa Basu, Taylor Flaat, Christopher Collado, Peter Weijmarshausen. Oncolytic VSV with retargeted glycoprotein and genetic ON switch for precise targeting of liver cancer using a synthetic virology platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 688.