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* From the Division of Pulmonary and Critical Care Medicine, Lexington Veterans Affairs Medical Center, University of Kentucky, Chandler Medical Center, Lexington KY.
Correspondence to: Edward A. Hirschowitz, MD, FCCP, Division of Pulmonary and Critical Care Medicine, University of Kentucky, Chandler Medical Center, 800 Rose St, Room MN 614, Lexington, KY 40536; e-mail: eahirs2{at}pop.uky.edu
Key Words: adenovirus cyclo-oxygenase-2 gene therapy non-small cell lung cancer
Infection
of epithelial-derived cells by adenovirus vectors has myriad effects on
cellular behavior and function. Some effects are relevant to the
desired effect of the encoded transgene and therapeutic goals of gene
therapy approach. The current experiments describe the induction of
cyclo-oxygenase (COX)-2 protein and prostaglandin (PGE)-2 production by
non-small cell lung cancer cells following infection with a first
generation (
E1,
E3) Ad vector. Notably, PGE-2 has been implicated
in tumor-induced immunosuppression.
E1,
E3-Ad vector infection of
non-small cell lung cancer cell line NCI-820 induced dose-dependent
increases in PGE-2 production (moi1050). Induction was related to the
transgene expressed. Detectable increases in COX-2 protein were seen by
Western blot 36 h after infection; these were paralleled by increases
in phosphorylation of extracellular signal-related kinase
(ERK)-1/2. Selective blockade of ERK with PD98029 reduced
constitutive COX-2 expression and prevented induction of PGE-2
following Ad infection. An inhibitor of nuclear factor (NF)-
B
translocation to the nucleus, SN50, had no effect on constitutive nor
inducible PGE-2 levels. In contrast, Ad vector infection did
induce NF-
B activity as measured by an NF-
B luciferase
reporter plasmid transfected into cell line NCI-820. Further,
UV/psoralen-inactivated vector did not have similar effects on PGE-2,
indicating the importance of gene expression. Ad vector infection leads
to ERK phosphorylation with parallel increases in COX-2 protein and
PGE-2 production. These effects appear unrelated to NF-
B and are
dependent on gene expression by the vector. In this context, induction
of PGE-2 by Ad vectors may need to be considered when defining targets
for immunogene therapy and/or choice of viral vector.
| Footnotes |
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Supported by Veterans Administration Career Development Award project No. 5964169050070001, and from a generous donation from the McDowell Foundation-Papa Johns/Valvano fund for cancer research.
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