[Expression of β-catenin in human pulmonary tissues of smokers with and without chronic obstructive pulmonary disease].

OBJECTIVE

To investigate the expression of β-catenin in pulmonary tissues of smokers with and without chronic obstructive pulmonary disease (COPD).

METHODS

Pulmonary tissues were obtained from patients who had underwent pneumonectomy in Tongji Hospital. The subjects were assigned into non-smokers without COPD (control group), smokers without COPD (smoker group) and smokers with COPD (smoker + COPD group) based on their pulmonary functions and smoking history, with 12 subjects each group. The specimens were obtained as far from the tumor focus (> 5 cm) as possible. Immunofluorescence staining, Western blot and real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) were used to investigate the expression and localization of β-catenin in pulmonary tissues. Numerical data were expressed as the mean ± standard deviation, and were assessed for significance by one-way analysis of variance followed by a Student-Newman-Keuls test for multiple comparisons. The difference of enumeration data was detected by Chi-Square test. Relationship was estimated by Pearson correlation.

RESULTS

Immunofluorescence analysis revealed that β-catenin mainly expressed in the cell membrane of epithelial cells. There was also a positive expression in the cytoplasm and the nuclei of the epithelial cells. The number of alveolar epithelial cells with β-catenin expressed in the cytoplasm and(or) nucleus was (1.2 ± 0.6)/HP in smokers + COPD group. And the protein and mRNA expression of β-catenin in pulmonary tissues in smokers + COPD group were 0.26 ± 0.11 and 0.351 ± 0.129, respectively, which were significantly less than those of the smoker group and the control group [(5.0 ± 2.5)/HP and (8.4 ± 3.5)/HP, 0.62 ± 0.23 and 1.00 ± 0.50, 0.60 ± 0.14 and 1.03 ± 0.27]. The differences among the 3 groups were significant (F = 12.809 - 38.776, P < 0.05). Correlation analysis between β-catenin expression and pulmonary function suggested that the protein and mRNA expression of β-catenin positively related with FEV(1)%pred (P < 0.05) and FEV(1)/FVC (r = 0.402 - 0.558, P < 0.05).

CONCLUSION

β-catenin expression significantly was decreased in smokers with COPD, and β-catenin level in the lungs was positively correlated with pulmonary function.