Antiproliferative effect of newcastle disease virus strain D90 on human lung cancer cell line A549.

: Newcastle disease virus (NDV) and variants of this virus have oncolytic properties and are potential anticancer agents. The objective of this study was to compare the effect of NDV strain D90 and strain D93 isolated from natural sources on human non-small cell lung cancer (NSCLC) cell line A549. We determined the 50% embryo infective dose (EID50) and 50% tissue culture infective dose (TCID50) of the NDV strains. The MTT assay was used to evaluate the effects of NDV strains on cell viability. We determined the expression of Annexin V and Bcl-2 proteins in NDV-infected cells. Light microscopy and electron microscopy indicated that the D90 strain significantly altered cell morphology and reduced cell viability, while strain D93 had negligible effects. Neither strain had a significant effect on normal cultured fetal liver cells. We used acridine orange staining to show that strain D90 (but not strain D93) induced nuclear fragmentation of A549 cells. An Annexin V-based apoptosis assay indicated that strain D90 (but not strain D93) caused significant apoptosis of A549 cells. Moreover, strain D90 (but not strain D93) significantly repressed the expression of Bcl-2 (an antiapoptotic protein) in A549 cells. Taken together, our results indicate that NDV strain D90 (but not strain D93) had no significant effect on normal cultured cells, but induced apoptosis of cultured NSCLC cells via a caspase-dependent pathway. These results suggest that NDV strain D90 has potential as an anticancer agent.