OBJECTIVETo investigate the mechanisms of apoptosis induced in human hepatoma cell line SMMC7721 by plasmid pVHN constructed with Newcastle disease virus (NDV) HN gene.

METHODSTwenty-four h after transfection with liposome-plasmid pVHN complexes in vitro, the mortality rate of SMMC7721 cells was determined by MTT staining and flow cytometry (FCM) with PI staining. The alteration of mitochondrial trans-membrane potential of the cells was detected by FCM with rhodamine 123 staining. Cell genomic DNA was detected by agarose electrophoresis. The activation of caspase-3 was assayed by its substrate color reaction.

RESULTSSignificant apoptosis was induced by transfection with plasmid pVHN into the cells for 24 h and the mortality rate was 50.0% (the mortality rate of control group was 5.2%). Genomic DNA was fragmented and mitochondrial trans-membrane potential was decreased, but caspase-3 activity increased.

CONCLUSIONSignificant apoptosis in SMMC7721 cells can be induced by NDV HN gene. Apoptosis may be resulted from the decrease of mitochondrial trans-membrane potential and activation of Caspase-3.