title: The involvement of nuclear factor-kappa B in cyclooxygenase-2 overexpression in murine colon cancer cells transduced with herpes simplex virus thymidine kinase gene.
abstract: We have previously reported that transduction of murine colon cancer cells (MC38) with herpes simplex virus thymidine kinase (HSV-tk) gene results in a significant enhancement of tumor growth rate in vivo and overexpression of cyclooxygenase-2 (COX-2). Our current study aimed to investigate the involvement of nuclear factor-kappa B (NF-kappaB), a pivotal transcriptional regulator of COX-2, in the upregulation of COX-2 expression by HSV-tk. It was found that HSV-tk gene transduction of MC38 cells results in significantly enhanced NF-kappaB activity, increased phosphorylation and degradation of inhibitor-kappa Balpha (IkappaBalpha) and enhanced translocation of NF-kappaB to the nucleus. Treatment of HSV-tk-transduced MC38 cells with sulfasalazine, a potent NF-kappaB inhibitor, led to dose-dependent inhibition of NF-kappaB activity, IkappaB phosphorylation and nuclear translocation of NF-kappaB, accompanied by significantly decreased COX-2 expression and reduced release of prostaglandin E2. Transient transfection experiments with COX-2 promoter constructs fused to luciferase reporter gene revealed that mutation in NF-kappaB-responsive element of COX-2 promoter significantly reduced promoter activity in HSV-tk-transduced MC38 and COS-7 cells, whereas it had no effect on promoter activity in the respective wild-type cells. At last, it was found that HSV-tk gene transduction causes significant enhancement of NF-kappaB activity and COX-2 expression in two additional tumor cell lines, 9L and T24. These findings suggest that HSV-tk gene transduction results in NF-kappaB pathway activation, which is essential for COX-2 overexpression by HSV-tk.
authors.affiliation: Department of Clinical Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Konson
authors.forename: J A
authors.initials: JA
authors.lastname: Mahajna
authors.forename: A
authors.initials: A
authors.lastname: Danon
authors.forename: G
authors.initials: G
authors.lastname: Rimon
authors.forename: R
authors.initials: R
authors.lastname: Agbaria
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics* / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D020672:I-kappa B Proteins / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D015398:Signal Transduction; D018139:Simplexvirus / Q000235:genetics*; D012460:Sulfasalazine / Q000494:pharmacology; D013937:Thymidine Kinase / Q000235:genetics*; D014158:Transcription, Genetic; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D020672:I-kappa B Proteins; D016328:NF-kappa B; D012460:Sulfasalazine; D051546:Cyclooxygenase 2; D013937:Thymidine Kinase; D015232:Dinoprostone