Fiber-modified adenoviral vector expressing the tumor necrosis factor-related apoptosis-inducing ligand gene from the human telomerase reverse transcriptase promoter induces apoptosis in human hepatocellular carcinoma cells.
OBJECTIVE
Because of a major resistance to chemotherapy, prognosis of hepatocellular carcinoma (HCC) is still poor. New treatments are required and gene therapy may be an option. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in multiple malignant tumors, and using adenoviral vectors has shown a targeted tumor-specific therapy. However, repeated administration of adenoviral vectors can lead to cell resistance, which may be caused by the initial coxsackie-adenovirus receptor (CAR). One technique to overcome resistance is the use of modified adenoviral vectors containing an Arg-Gly-Asp (RGD) sequence. In this study we constructed an adenoviral vector (designated Ad/TRAIL-F/RGD) with RGD-modified fibers, expressing the TRAIL gene from the human telomerase reverse transcriptase (hTERT) promoter, and evaluated its antitumor activity in HCC cell lines.


METHODS
To investigate the effects of Ad/TRAIL-F/RGD in human HCC cell lines Hep G2 and Hep 3b, cells were infected with Ad/CMV-GFP (vector control), Ad/gTRAIL (positive control), and Ad/TRAIL-F/RGD. Phosphate-buffered saline (PBS) was used as control. Cell viability was determined by proliferation assay (XTT), and apoptosis induction by fluorescence activated cell sorting (FACS).


RESULTS
Cells treated with Ad/TRAIL-F/RGD and Ad/gTRAIL showed a significantly reduced cell viability in comparison to PBS and Ad/CMV-GFP treatment in both cell lines. Whereas, treatment with PBS and Ad/CMV-GFP had no cell-killing effect. The reduced cell viability was caused by induction of apoptosis as shown by FACS analysis. The amount of apoptotic cells was similar after incubation with Ad/gTRAIL and Ad/TRAIL-F/RGD.


CONCLUSIONS
The new RGD modified vector Ad/TRAIL-F/RGD could become a potent therapeutic agent for the treatment of HCC, adenovirus resistant tumors, and CAR low or negative cancer cells.
Jacob
Dietmar
D
Department of General, Visceral and Transplantation Surgery, Humboldt University of Berlin, CharitA Virchow Clinic, Augustenburger Platz 1, 13353 Berlin, Germany. dietmar.jacob@charite.de
Schumacher
Guido
G
Bahra
Marcus
M
Davis
John
J
Zhu
Hong-Bo
HB
Zhang
Li-Dong
LD
Teraishi
Fuminori
F
Neuhaus
Peter
P
Fang
Bing-Liang
BL
D000256:Adenoviridae / Q000235:genetics; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000628:therapy*; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000628:therapy*; D008562:Membrane Glycoproteins / Q000235:genetics*; D011401:Promoter Regions, Genetic; D053221:TNF-Related Apoptosis-Inducing Ligand; D019098:Telomerase / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D051017:Apoptosis Regulatory Proteins; D004268:DNA-Binding Proteins; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D019098:Telomerase