Newcastle Disease Virus Induces Pyroptosis in Canine Mammary Tumour CMT-U27 Cells via the TNFα/NF-κB/NLRP3 Signalling Pathway.

Abstract

Mammary tumours are the most common type of neoplasm in female dogs, with nearly half being malignant. Oncolytic Newcastle disease virus (NDV) therapy has emerged as a novel cancer treatment option; however, its precise oncolytic mechanism in canine mammary tumours (CMT) remain unclear. Ultrastructural analysis of NDV-infected CMT-U27 cells with locally damaged cell membranes and swollen and ruptured mitochondria revealed the occurrence of pyroptosis. Transcriptome sequencing further identified a significant upregulation of pyroptosis-related genes, including NLRP1, NOD2, caspase-1, and GSDMD. Subsequent examination of RNA and protein expression levels of pyroptosis-related molecules in vitro indicated that NDV induces pyroptosis in CMT-U27 cells via the caspase-1/GSDMD pathway. Additionally, inhibition of the TNFα/NF-κB pathway and knockdown of NOD-like receptor pyrin domain-containing protein 3 (NLRP3) using small interfering RNA demonstrated that the TNFα/NF-κB pathway can regulate NDV-induced pyroptosis through the NLRP3 inflammasome. In a xenograft model, intravenous administration of NDV significantly inhibited tumour growth, and prolonged the survival time in nude mice bearing CMT-U27 cells. NDV treatment enhances intratumoural pyrotosis in tumour bearing mice. In conclusion, these findings suggest that NDV induces pyroptosis in CMT-U27 cells through the TNFα/NF-κB/NLRP3 pathway, providing a foundation for future research into NDV's therapeutic potential in canine mammary cancer.