Cyclooxygenase 2 promoter-based replication-selective adenoviral vector for hypopharyngeal cancer.

OBJECTIVE To explore the potential clinical application of the oncolytic activity of cyclooxygenase 2 (COX-2) promoter-based, conditional, replication-selective adenovirus vector for hypopharyngeal squamous cell carcinoma. DESIGN In vivo study and retrospective study. SETTING Kobe University Hospital, Kobe, Japan. SUBJECTS Expression of COX-2 in hypopharyngeal cancers treated at Kobe University Hospital was immunohistochemically investigated. In addition, nude mice bearing human hypopharyngeal cancer cells (H891) were used to analyze oncolytic activity of a conditional replication-selective adenovirus vector in which the expression of E1a, required for viral replication, is controlled by the COX-2 promoter Ad-COX2-E1a. RESULTS In vivo assays showed significant growth suppression in the murine hypopharyngeal model. Cyclooxygenase 2 expression was observed in 75.3% of hypopharyngeal cancers, especially in differentiated tumor cells (P = .001; r = 0.433). CONCLUSION In this study, we demonstrated the potential of oncolytic therapy using the COX-2-promoter based, conditional, replication-selective adenovirus for COX-2-expressing hypopharyngeal squamous cell carcinomas.