Adenovirus vectors activate survival pathways in lung epithelial cells.
Airway epithelial cells are often the sites of targeted adenovirus vector delivery. Activation of the host inflammatory response and modulation of signal transduction pathways by adenovirus vectors have been previously documented, including activation of MAP kinases and phosphatidylinositol 3-kinase (PI3-kinase). The effect of activation of these pathways by adenovirus vectors on cell survival has not been examined. Both the PI3-kinase/Akt and ERK/MAP kinase signaling pathways have been linked to cell survival. Akt has been found to play a role in cell survival and apoptosis through its downstream effects on apoptosis-related proteins. Constitutive activation of either PI3-kinase or Akt blocks apoptosis induced by c-Myc, UV radiation, transforming growth factor-beta, Fas, and respiratory syncytial virus infection. We examined the effect of adenovirus vector infection on activation of these prosurvival pathways and its downstream consequences. Airway epithelial cells were transduced with replication-deficient adenoviral vectors containing a nonspecific transgene, green fluorescent protein driven by the cytomegalovirus promoter, or an empty vector with no transgene. They were then exposed to the proapoptotic stimulus actinomycin D plus TNF-alpha, and evidence of apoptosis was evaluated. Compared with the cells treated with actinomycin/TNF alone, the adenovirus vector-infected cells had a 50% reduction in apoptosis. When we examined induction of the prosurvival pathways, ERK and AKT, in the viral vector-infected cells, we found that there was significant activation of both Akt and ERK.
Flaherty
Dawn M
DM
Department of Internal Medicine, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa City, Iowa 52242, USA. flahertydm@mail.medicine.uiowa.edu)
Hinde
Sara L
SL
Monick
Martha M
MM
Powers
Linda S
LS
Bradford
Mary A
MA
Yarovinsky
Timur
T
Hunninghake
Gary W
GW
D002282:Adenocarcinoma, Bronchiolo-Alveolar; D000256:Adenoviridae / Q000235:genetics*; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000502:physiology; D015967:Gene Expression Regulation, Viral; D005822:Genetic Vectors / Q000502:physiology*; D006801:Humans; D008175:Lung Neoplasms; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D020545:Respiratory Mucosa / Q000166:cytology* / Q000502:physiology*; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000970:Antineoplastic Agents; D011518:Proto-Oncogene Proteins; D014409:Tumor Necrosis Factor-alpha; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases