Bibliographic Details
| Title: |
Cholera toxin, a typical protein kinase A activator, induces G1 phase growth arrest in human bladder transitional cell carcinoma cells via inhibiting the c-Raf/MEK/ERK signaling pathway. |
| Authors: |
XIAOKE ZHENG, YANQIU OU, MINFENG SHU, YOUQIONG WANG, YUXI ZHOU, XINGWEN SU, WENBO ZHU, WEI YIN, SHIFENG LI, PENGXIN QIU, GUANGMEI YAN, JINGXIA ZHANG, JUN HU, DONG XU |
| Source: |
Molecular Medicine Reports; 2014, Vol. 9 Issue 5, p1773-1779, 7p |
| Subject Terms: |
CHOLERA toxin, CYCLIC-AMP-dependent protein kinase, TRANSITIONAL cell carcinoma, NEOPLASTIC cell transformation, BLADDER tumors, CELLULAR signal transduction, CELL proliferation |
| Abstract: |
The biotoxin cholera toxin has been demonstrated to have anti-tumor activity in numerous types of cancer, including glioma. However, the role of cholera toxin in the tumorigenesis of transitional cell carcinoma (TCC), the most common malignant tumor of the bladder, remains to be elucidated. To address this, in the present study, two TCC cell lines, T24 and UM-UC-3, were treated with cholera toxin [protein kinase A (PKA) activator] and KT5720 (PKA inhibitor). Cell survival and proliferation, cell cycle alterations and apoptosis were analyzed using Hoechst staining, the MTT assay, fluorescence microscopy and flow cytometry. Western blot analysis was used to detect the expression of proteins involved in cell cycle regulation. The results revealed that cholera toxin significantly induced Gl arrest and downregulated the expression of cyclin Dl and cyclin-dependent kinase 4/6 in the TCC cell lines, and this was rescued by KT5720. Furthermore, it was demonstrated that cholera toxin downregulated the activation of the c-Raf/Mek/Erk cascade, an important mediator of tumor cell proliferation, via the PKA-dependent c-Raf phosphorylation at Ser-43. Furthermore, inhibition of Mek activity with U0126 mimicked the effects of cholera toxin. In conclusion, these results confirmed that cholera toxin specifically inhibited proliferation and induced Gl phase arrest in human bladder TCC cells. This effect was due to PKA-dependent inactivation of the c-Raf/Mek/Erk pathway. This suggested that cholera toxin may be a viable therapeutic treatment against tumorigenesis and proliferation in bladder cancer. [ABSTRACT FROM AUTHOR] |
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| Database: |
Complementary Index |
