Expression and Distributional Patterns of the Inhibitor of Apoptosis Protein Family and Caspase 3 in Nasal Polyps

Abstract

To investigate the expression and distributional patterns of the inhibitor of apoptosis protein (IAP) family and caspase 3 in nasal polyps and normal nasal mucosa and to evaluate the possible effects of the IAP family and caspase 3 on the development of nasal polyps. Prospective study. Tertiary academic institution. Normal inferior turbinate mucosa was obtained from 20 patients undergoing surgery for augmentation rhinoplasty. Nasal polyps were obtained from 20 patients undergoing endoscopic sinus surgery for chronic polypoid sinusitis. Reverse transcriptase-polymerase chain reaction, immunohistochemical analysis, and Western blot analysis were performed. The expression and distribution of cIAP1, cIAP2, XIAP, survivin, and caspase 3 were evaluated in normal turbinate mucosa and nasal polyps. cIAP1, cIAP2, and XIAP were expressed in normal human nasal mucosa, where they were detected in submucosal glands, epithelial cells, vascular endothelial cells, and inflammatory cells. However, cIAP1 was not expressed in nasal polyps, whereas cIAP2 and XIAP were expressed in submucosal glands, epithelial cells, vascular endothelial cells, and inflammatory cells. Caspase 3 was localized to a portion of the epithelial cells in normal nasal mucosa and nasal polyps. Survivin was not expressed in any samples. Furthermore, cIAP2, XIAP, and caspase 3 did not show a significant difference in their expression levels between normal nasal mucosa and nasal polyps. The present results indicate that cIAP1, cIAP2, XIAP, and caspase 3 may regulate the homeostasis of normal nasal mucosa, whereas cIAP2, XIAP, and caspase 3 may take part in the pathogenesis of nasal polyps.