# HRS Facilitates Newcastle Disease Virus Replication in Tumor Cells by Promoting Viral Budding

## TL;DR

This study shows that HRS helps the Newcastle disease virus replicate in tumor cells by aiding viral budding, which could improve oncolytic virus therapies.

## Contribution

The study identifies HRS as a key ESCRT component that promotes NDV replication through viral budding in tumor cells.

## Key findings

- HRS knockdown significantly impaired NDV replication in HeLa cells.
- HRS knockout inhibited viral budding and suppressed NDV-induced cell death.
- NDV infection upregulates HRS gene and protein expression over time.

## Abstract

Newcastle disease virus (NDV) is a highly pathogenic avian infectious disease agent and also a promising oncolytic virus with broad application prospects. The Endosomal Sorting Complex Required for Transport (ESCRT) machinery has been increasingly recognized for its crucial role in the life cycles of enveloped viruses, influencing processes such as viral entry, replication, and budding. In this study, we employed an RNA interference screening approach to identify key ESCRT components that regulate NDV replication in tumor cells. qPCR, immunofluorescence, and Western blot assays demonstrated that knockdown of HRS, CHMP4A, CHMP4B, and CHMP4C significantly impaired NDV replication in HeLa cells, with HRS exhibiting the most pronounced inhibitory effect. Additionally, HRS knockout significantly inhibited viral budding and suppressed NDV-induced cell death in HeLa cells. Notably, NDV infection was shown to significantly upregulate HRS gene and protein expression in a time-dependent manner. In conclusion, this study systematically identifies critical ESCRT components involved in NDV replication within tumor cells, with a particular focus on the role of HRS in promoting NDV’s replication by promoting viral budding, offering new insights for the development of NDV-based oncolytic therapies.