title: Enhancement of adenoviral MDA-7-mediated cell killing in human lung cancer cells by geldanamycin and its 17-allyl- amino-17-demethoxy analogue.
abstract: Our previous studies demonstrated that adenovirus-mediated overexpression of melanoma differentiation-associated gene-7 (Ad-mda7) leads to rapid induction of double-stranded RNA-dependent protein kinase (PKR) and activation of its downstream targets, resulting in apoptosis induction in human lung cancer cells. Here, we report that Ad-mda7 and the benzoquinone ansamycin geldanamycin (GA) interact in a highly synergistic manner to induce cell death in human lung cancer cells. Co-administration of Ad-mda7 and GA did not modify expression of MDA-7, and was not associated with further PKR induction and activation; instead the enhanced cytotoxicity of this combination was associated with inactivation of AKT by GA. By surface staining using anti-E-cadherin monoclonal antibody and flow cytometry, we found that treatment with the combination of Ad-mda7 and GA increased E-cadherin levels in these cancer cells. Ad-mda7 and GA cotreatment also inhibited lung cancer cell motility by increasing the beta-catenin/E-cadherin association. Moreover, combination of GA derivative 17-allyl-amino, 17-demethoxygeldanamycin (17AAG), with Ad-mda7 resulted in enhancement of cell death in A549 and H460 human lung cancer cells.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Box 445, Houston, TX 77030, USA. apataer@mdanderson.org
authors.forename: A
authors.initials: A
authors.lastname: Pataer
authors.forename: D
authors.initials: D
authors.lastname: Bocangel
authors.forename: S
authors.initials: S
authors.lastname: Chada
authors.forename: J A
authors.initials: JA
authors.lastname: Roth
authors.forename: K K
authors.initials: KK
authors.lastname: Hunt
authors.forename: S G
authors.initials: SG
authors.lastname: Swisher
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D016227:Benzoquinones / Q000737:chemistry / Q000494:pharmacology*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005822:Genetic Vectors; D006801:Humans; D047029:Lactams, Macrocyclic / Q000737:chemistry / Q000494:pharmacology*; D008175:Lung Neoplasms / Q000473:pathology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*
chemical_list: D016227:Benzoquinones; D047029:Lactams, Macrocyclic; D047428:Protein Kinase Inhibitors; D011505:Protein-Tyrosine Kinases; C001277:geldanamycin