Effects of etodolac, a selective cyclooxygenase-2 inhibitor, on the expression of E-cadherin-catenin complexes in gastrointestinal cell lines.
BACKGROUND
Recent studies have shown that cyclooxygenase-2 (COX-2) inhibitors may participate in the proliferation of cancer cells. Because the cadherin-catenin complex is not only a key component of the adherens junction but also has been suggested to regulate cell proliferation, modulation of these molecules may be a mechanism by which COX-2 activity affects cell proliferation. In this study, we evaluated the effect of a COX-2 inhibitor on the proliferation and expression of E-cadherin-complexes in gastrointestinal cancer cell lines.


METHODS
The gastrointestinal cancer cell lines Caco2, HT29, and MKN45 were grown for 24 h in the presence and absence of a selective COX-2 inhibitor, etodolac (10(-5), 10(-4), and 10(-3) M). Cell proliferation was assessed by (3)H-thymidine incorporation, and the expression of E-cadherin and catenins was assessed by Western blotting, Northern blotting, and immunofluorescence.


RESULTS
Etodolac induced a significant reduction in cell proliferation in Caco2 and MKN45 cells. E-cadherin expression was upregulated after stimulation with etodolac in Caco2 cells, whereas the expression of alpha-, beta-, gamma- and p120-catenins was not modified. The expression of E-cadherin mRNA was also upregulated in Caco2 cells, and was upregulated also in MKN45 cells, which did not express normal E-cadherin protein by the use of a mouse monoclonal antibody against human E-cadherin, HECD-1 antibody. Immunofluorescence revealed that the increased E-cadherin was localized at the cytoplasmic membrane.


CONCLUSIONS
The inhibition of cell growth by etodolac in Caco-2 cells was associated with a dose-dependent upregulation and intense cytoplasmic localization of E-cadherin. No quantitative change in catenin expression was found in this phenomenon. These findings suggest that the COX-2 inhibitor affects the transcription of E-cadherin, or that there may be some homeostatic link between the cell cycle and E-cadherin transcription.
Noda
Masao
M
Third Department of Internal Medicine, Kyoro Prefectural University of Medicine, 465 Kaiji-cho, Kamigyo-ku, Kyoto 602-8566, Japan.
Tatsumi
Yoichi
Y
Tomizawa
Muneta
M
Takama
Takafumi
T
Mitsufuji
Shoji
S
Sugihara
Hiroyuki
H
Kashima
Kei
K
Hattori
Takanori
T
D000818:Animals; D018938:Caco-2 Cells / Q000187:drug effects; D015820:Cadherins / Q000032:analysis / Q000187:drug effects* / Q000235:genetics; D002277:Carcinoma / Q000235:genetics / Q000503:physiopathology*; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D003598:Cytoskeletal Proteins / Q000032:analysis / Q000187:drug effects* / Q000235:genetics; D051180:Desmoplakins; D017308:Etodolac / Q000494:pharmacology*; D005770:Gastrointestinal Neoplasms / Q000235:genetics / Q000503:physiopathology*; D015870:Gene Expression / Q000187:drug effects* / Q000235:genetics; D019073:HT29 Cells / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D008565:Membrane Proteins; D051379:Mice; D011451:Prostaglandin-Endoperoxide Synthases / Q000494:pharmacology*; D015534:Trans-Activators / Q000032:analysis / Q000187:drug effects* / Q000235:genetics; D014407:Tumor Cells, Cultured / Q000187:drug effects*; D051178:alpha Catenin; D051176:beta Catenin
C495273:CTNNA1 protein, human; C495270:CTNNB1 protein, human; C495267:CTNNB1 protein, mouse; D015820:Cadherins; C495272:Ctnna1 protein, mouse; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D003598:Cytoskeletal Proteins; D051180:Desmoplakins; D007527:Isoenzymes; D008565:Membrane Proteins; D015534:Trans-Activators; D051178:alpha Catenin; D051176:beta Catenin; D017308:Etodolac; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases