Upregulation of Bcl‐2 in nasal polyps from patients with cystic fibrosis

Scapa, Victor I.; Ramakrishnan, Vijay R.; Kingdom, Todd T.

BACKGROUND: Nasal polyps in patients with cystic fibrosis (CF) are believed to be phenotypically different than polyps affecting non‐CF patients. The aim of this study was to investigate differences in cell cycle regulatory mechanisms between these 2 groups. In this prospective study at a tertiary care academic medical center, multiple techniques were used to confirm the upregulation of antiapoptotic Bcl‐2 family proteins in CF polyps. METHODS: Nasal polyps were prospectively obtained from CF and non‐CF patients. The Sigma Panorama Protein Microarray for Cell Signaling was used to identify differences in protein expression between the 2 polyp groups. Western blot analysis confirmed altered expression of a subset of these proteins. Immunohistochemical staining was performed on archived tissue to further investigate B‐cell lymphoma 2 protein (Bcl‐2) expression. Following review by a pathologist, slides were digitized using an Aperio™ ScanScope XT system and staining intensity was quantified with the Positive Pixel Count algorithm. The mean staining intensity for each polyp group was compared. RESULTS: The protein microarray suggested a greater than 2‐fold upregulation of Bcl‐xl in CF polyps relative to non‐CF polyps. Western blot analysis confirmed the upregulation in CF polyps of Bcl‐2, a more commonly studied protein analog of Bcl‐xl. The CF polyp group was noted to have a higher quantitative intensity of immunohistochemical staining for Bcl‐2 compared to the non‐CF group (p < 0.05). CONCLUSION: Through multiple modalities of protein investigation, we have demonstrated an upregulation of Bcl‐2 family proteins in CF polyps relative to polyps from non‐CF patients.