Oncolytic Effect of Newcastle Disease Virus AF2240 Strain on the MCF-7 Breast Cancer Cell Line

Objective: This study was carried out to investigate the oncolytic effect of the Newcas- tle disease virus (NDV) strain AF2240 on the MCF-7 breast cancer cell line. Materials and Methods: The NDV-AF2240 was propagated in 11 days old embryo- nated chicken eggs for 72 hours. The virus in the allantoic fluid was harvested and purified. The haemagglutination (HA) test was conducted on the purified virus to deter- mine the virus titre which was 16384 haemagglutination units (HAUs). The microculture tetrazolium assay (MTA) was carried out via two methods-the monolayer and co-culture techniques- to determine the inhibitory concentration (IC50) of NDV-AF2240 against the MCF-7 breast cancer cell line. Confocal laser scanning microscopy was carried out on polyclonal chicken antibody and fluorescein isothiocynate (FITC) conjugated goat anti- chicken antibody to observe virus localization in the cells. The terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay was conducted to quan- tify the percentage of apoptotic cells. Results: IC50 value of NDV-AF2240 was two HAUs in both the monolayer and co-cul- tures. Virus particles were detected in the cytoplasm of MCF-7 breast cancer cell line after 24 and 48 hours post treatment. Virus budding was detected 72 hours post treat- ment. The number of apoptotic cells was significantly increased (p < 0.05) 72 hours post NDV-AF2240 treatment. Conclusion: The findings of this study show that NDV-AF2240 has an oncolytic effect against the MCF-7 breast cancer cell line. Further studies are needed to understand the anti cancer mechanism of this virus.