Apoptosis Induction of Newcastle Disease Virus Strains (AF 2240 & V4-UPM) on HT-29Human Colorectal Adenocarcinoma Cells

Newcastle disease virus (NDV) is a negative-sense single stranded RNA virus of the Paramyxoviridae family that causes severe disease in several avian species. NDV has been shown to possess oncolytic properties and in the current study, the effect of NDV strains AF 2240 and V4-UPM on the HT-29 human colorectal adenocarcinoma cells was observed. The cytolytic effects of the virus strains were determined by using MTT assay. The CD50 value for cytolytic effects of NDV strains AF 2240 and V4-UPM on HT-29 after 72h was 16 and 33 HAU mL -1 , respectively. No cytolytic effect was observed on 3T3 normal mouse fibroblast cells when treated with CD50 dose of both NDVstrains. HT-29 cells were analyzed by using AO/PI staining method and observed that NDV treatment with both strains induced a time-dependent increasing in apoptosis of treated cells compared to non-treated HT-29 cells. Analysis of caspases 3, 8 and 9 the key executioners in apoptosis has shown that both 3 and 9 caspases were significantly increased in HT-29 after treatment with both NDVstrains.The effects of both strains of NDV on the expression level of apoptosis-associated proteins revealed an increased in Bax and decreased in Bcl-2 protein levels. The results suggest that NDV strains AF 2240 and V4-UPM induced apoptosis on HT-29 cells.