In vitro efficacy of AdTRAIL gene therapy of bladder cancer is enhanced by trichostatin A-mediated restoration of CAR expression and downregulation of cFLIP and Bcl-XL.
Current therapies for bladder cancer are suboptimal and adenoviral gene therapy has been explored as an alternative treatment. In this study, we evaluated the in vitro efficacy of an adenovirus expressing TNF-related apoptosis-inducing ligand (AdTRAIL). At low concentrations of virus, T24 cells were more resistant to AdTRAIL-induced apoptosis than 5637 bladder carcinoma cells. Resistance in T24 cells correlated with poor infectivity and lack of surface expression of coxsackie and adenovirus receptor (CAR). Pretreatment with low concentrations of the histone deacetylase inhibitor trichostatin A, restored CAR expression in T24 cells, which facilitated viral infection and resulted in apoptosis at low concentrations of AdTRAIL. In addition, trichostatin A reduced the expression of Bcl-X(L) and cFLIP resulting in increased sensitivity to recombinant TRAIL. Overexpression of cFLIP inhibited TRAIL-mediated killing in trichostatin A pretreated cells, indicating that downregulation of this antiapoptotic protein is required for sensitization. Therefore, trichostatin A can enhance the efficacy of AdTRAIL by restoring CAR expression and by generating a more pro-apoptotic phenotype that would facilitate bystander activity of TRAIL. Combination of histone deacetylase inhibitors with intravesical AdTRAIL gene therapy may be a novel treatment strategy for bladder cancer.
El-Zawahry
A
A
Department of Microbiology & Immunology, Medical University of South Carolina, Charleston, 29403, USA.
Lu
P
P
White
S J
SJ
Voelkel-Johnson
C
C
D000256:Adenoviridae / Q000235:genetics*; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000235:genetics*; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D015536:Down-Regulation; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D015316:Genetic Therapy; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids / Q000627:therapeutic use*; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000235:genetics*; D011991:Receptors, Virus / Q000378:metabolism*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*; D001749:Urinary Bladder Neoplasms / Q000378:metabolism / Q000628:therapy*; D051020:bcl-X Protein / Q000378:metabolism*
D051017:Apoptosis Regulatory Proteins; C494811:BCL2L1 protein, human; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; C568771:CLMP protein, human; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D011991:Receptors, Virus; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D051020:bcl-X Protein; C012589:trichostatin A