# The oncolytic vesicular stomatitis virus VSV-GP shows profound oncolytic activity in NUT-carcinoma cell lines

## TL;DR

This study shows that the oncolytic virus VSV-GP effectively kills NUT carcinoma cells and identifies factors influencing its effectiveness.

## Contribution

The first evaluation of VSV-GP's virotherapeutic efficacy in NUT carcinoma cell lines.

## Key findings

- VSV-GP caused significant oncolysis and apoptosis in five out of seven NUT carcinoma cell lines.
- Resistance mechanisms were linked to functional IFN-β signaling despite suppressed IFN-β synthesis.
- VSV-GP's entry receptor was equally expressed in both permissive and resistant cell lines.

## Abstract

NUT carcinoma (NC) is a rare, yet aggressive disease (median survival of 6.5 months) of the young defined by a translocation of the nuclear protein in testis gene 1 (NUTM1). Neither surgery nor radiochemotherapy or targeted therapies provide effective disease control, thereby creating a need for innovative therapeutic strategies. Recently, the recombinant oncolytic virus (OV) VSV-GP entered phase I clinical testing (NCT05155332). We (1) visualized VSV-GPs’ replication cycle in transmission electron microscopy; (2) analyzed VSV-GP’s oncolytic efficacy and replication kinetics using viability assays, xCELLigence analyses, RT-qPCR, TCID50 assays, and FACS analysis; as well as (3) explored potential resistance mechanisms in seven human NC cell lines. Upon infection with VSV-GP, we noticed profound oncolysis, apoptosis, and high replication kinetics in five out of seven NC cell lines. Investigations of molecular determinants of resistance showed that VSV-GPs’ entry receptor α-dystroglycan was equally expressed by VSV-GP-permissive and -resistant cell lines. While synthesis of intrinsic interferon (IFN)-β was found to be suppressed in VSV-GP-infected NC cell lines, intracellular IFN-β signaling was functional. Since VSV-GP is a promising compound for virotherapy of NC patients, exploration of virus-induced immunogenicity and identification of resistance mechanisms could pave the way for additional combination treatment regimes in NC.

This work presents the first evaluation of the virotherapeutic efficacy of the oncolytic virus VSV-GP-GFP in NUT carcinoma cell lines. The authors provide key insights into VSV-GP-GFP’s oncolytic activity and cellular resistance mechanisms, thereby establishing a foundation for the potential therapeutic application in this frequently fatal malignancy.