Adenovirus-mediated Bak gene transfer induces apoptosis in mesothelioma cell lines.
OBJECTIVE
Conventional treatment for mesothelioma is largely ineffective. We therefore evaluated the novel approach of adenoviral gene transfer of the proapoptotic Bcl-2 family member Bak in mesothelioma cancer cell lines, which are sensitive and resistant to adenoviral p53.


METHODS
Binary adenoviral Bak (Ad/GT-Bak and Ad/GV16) and LacZ (Ad/GT-LacZ and Ad/GV16) vectors were used for transduction of the mesothelioma cell lines I-45 (p53 resistant) and REN (p53 sensitive). Protein levels were determined by Western blotting. Apoptosis was assessed by morphologic changes, caspase-3 cleavage, and fluorescence-activated cell sorter analysis of subdiploid populations. Cell viability was determined with the XTT assay. Statistical analysis was performed with analysis of variance and the Student t test.


RESULTS
High levels of Bak gene transfer were seen after coadministration of Ad/GT-Bak and Ad/GV16 in both mesothelioma cell lines. Apoptosis was induced 24 hours after Bak but not LacZ gene transfer ([Bak: I-45, 36%; REN, 25%] vs [LacZ: I-45, 1%; REN, 3%], P <.05]) in p53-sensitive (REN) and p53-resistant (I-45) cell lines. Cellular viability was significantly decreased 48 to 72 hours after Bak gene transfer compared with control vector in both cell lines (72 hours: Bak I-45, 1.4% +/- 1.0%, and Bak REN, 4.7% +/- 1%, vs Lac-Z I-45, 83% +/- 3%, and Lac-Z REN, 100% +/- 1%; P <.05).


CONCLUSIONS
Adenovirus-mediated overexpression of the Bak gene induces apoptosis and decreased cellular viability in p53-sensitive and p53-resistant mesothelioma cells. These data suggest that the gene transfer of proapoptotic Bcl-2 family members may represent a novel gene therapy strategy to treat mesothelioma.
Pataer
A
A
Department of Thoracic and Cardiovascular Surgery, and the Department of Molecular Pathology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
Smythe
W R
WR
Yu
R
R
Fang
B
B
McDonnell
T
T
Roth
J A
JA
Swisher
S G
SG
D000256:Adenoviridae / Q000235:genetics*; D017209:Apoptosis / Q000235:genetics; D015153:Blotting, Western; D002470:Cell Survival; D005434:Flow Cytometry; D015870:Gene Expression; D005822:Genetic Vectors; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008654:Mesothelioma / Q000235:genetics / Q000473:pathology* / Q000821:virology; D009154:Mutation; D010997:Pleural Neoplasms / Q000235:genetics / Q000473:pathology* / Q000821:virology; D014161:Transduction, Genetic / Q000379:methods*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D050998:bcl-2 Homologous Antagonist-Killer Protein
C494772:BAK1 protein, human; D008565:Membrane Proteins; D016159:Tumor Suppressor Protein p53; D050998:bcl-2 Homologous Antagonist-Killer Protein