Anti-liver cancer activity of TNF-related apoptosis-inducing ligand gene and its bystander effects.
OBJECTIVE
To observe the anti-liver cancer activity of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene and its bystander effects on hepatocellular carcinoma (HCC) cell line SMMC7721.


METHODS
Full-length cDNA of human TRAIL was transferred into SMMC7721 cells with a binary adenoviral vector system. Polymerase-chain reaction following reverse transcription (RT-PCR) was used to determine the expression of TRAIL gene. Effects of the transfected gene on proliferation of SMMC7721 cells were measured by MTT assay. Its influence on apoptosis was demonstrated by fluorescence-activated cell sorting (FACS). The bystander effect was observed by co-culturing the SMMC7721 cells with and without the transfected TRAIL gene at different ratios, and the culture medium supernatant from the transfected cells was also examined for its influence on SMMC7721 cells.


RESULTS
The growth-inhibition rate and apoptotic cell fraction in the cells transfected with the TRAIL gene, Bax gene or only LacZ gene were 91.2%, 48.0%, 28.8% and 29.1%, 12.5%, 6.6%, respectively. The growth-inhibition rate of transfection with these three sequences in normal human fibroblasts was 6.1%, 45.5% and 7.6%, respectively, indicating a discriminative inhibition of TRAIL transfection on the cancer cells. In the co-culturing test, addition of the transfected TRAIL to SMMC7721 cells in proportions of 5%, 25%, 50%, 75% and 100%, resulted in a growth-inhibition of 15.9%, 67%, 80.2%, 86.4% and 87.7%, respectively. We failed to observe a significant growth-inhibition effect of the culture medium supernatant on SMMC7721 cells.


CONCLUSIONS
TRAIL gene transferred by a binary adenoviral vector system can inhibit proliferation of SMMC7721 cells and induce their apoptosis. A bystander effect was observed, which seemed not to be mediated by soluble factors.
He
Chao
C
Department of Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang Province, China. drhe@zju.edu.cn
Lao
Wei-Feng
WF
Hu
Xiao-Tong
XT
Xu
Xiang-Ming
XM
Xu
Jing
J
Fang
Bing-Liang
BL
D000256:Adenoviridae / Q000235:genetics; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D024201:Bystander Effect; D006528:Carcinoma, Hepatocellular; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor / Q000166:cytology / Q000502:physiology; D002470:Cell Survival; D005347:Fibroblasts / Q000166:cytology; D006801:Humans; D008113:Liver Neoplasms; D008562:Membrane Glycoproteins / Q000235:genetics*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha