[Effects of cigarette smoke extract on the expression of beta-catenin and tyrosine phosphorylation in airway epithelial cells].
OBJECTIVE
To explore the possible mechanism of injury by smoking and its repairing, the effects of cigarette smoke extract on the expression of beta-catenin (beta-cat), c-Src and level of phosphoric tyrosine in airway epithelial cells (AEC).


METHODS
Pig AECs were cultured in vitro. After CSE and tyrphostin 25 exposure, (1) the expression of beta-cat was determined by immunocytochemical stain in 300 randomly selected AECs of each group, (2) the level of phosphoric tyrosine, content of c-Src and beta-cat mRNA in AECs were evaluated by immunocytochemical stain, in situ hybridization and image analysis in 30 randomly selected AECs of each group.


RESULTS
After exposure to CSE for 4 hours and 24 hours, the levels of phosphoric tyrosine were 1.51 and 3.44 times of that of the control groups of the same time (P < 0.0001) respectively; the ratio of positive stain of beta-cat on membrane was markedly lower than that in the control groups (78.3% vs 83.3%, 77.7% vs 81.3%, P < 0.0001), and the cytoplasmic content of c-Src decreased 47.9% and 51.4% (P < 0.0001) compared with the control groups of the same time, respectively. While dealt with CSE and tyrphostin 25 together, the level of phosphoric tyrosine, the expression of beta-cat and c-Src resembled those in normal control. Contends of beta-cat mRNA decreased in the both two situations (P < 0.0010).


CONCLUSIONS
CSE decreased the membranous expression of beta-cat and increased the level of tyrosine phosporylation of AECs. The change of beta-cat expression might mediate the airway epithelial injuries caused by smoking, and tyrphostin 25 might prevent such injuries through inhibiting the tyrosine kinase.
Chen
F
F
Department of Pathology, Tongji Medical College, Huazhong Science and Technology University, Wuhan 430030, China.
Wu
R
R
Wang
X
X
D000818:Animals; D001980:Bronchi / Q000166:cytology / Q000378:metabolism*; D000081247:CSK Tyrosine-Protein Kinase; D003598:Cytoskeletal Proteins / Q000096:biosynthesis* / Q000235:genetics; D004847:Epithelial Cells / Q000378:metabolism; D007150:Immunohistochemistry; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D012906:Smoke / Q000009:adverse effects*; D013552:Swine; D014026:Nicotiana; D014132:Trachea / Q000166:cytology / Q000378:metabolism*; D015534:Trans-Activators; D014443:Tyrosine / Q000378:metabolism*; D051176:beta Catenin; D019061:src-Family Kinases
D003598:Cytoskeletal Proteins; D012333:RNA, Messenger; D012906:Smoke; D015534:Trans-Activators; D051176:beta Catenin; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases