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Wang Y, Sun HY, Liu YG, Song Z, She G, Xiao GS, Wang Y, Li GR, Deng XL. Tyrphostin AG556 increases the activity of large conductance Ca 2+ -activated K + channels by inhibiting epidermal growth factor receptor tyrosine kinase. J Cell Mol Med 2017; 21:1826-1834. [PMID: 28294531 PMCID: PMC5571560 DOI: 10.1111/jcmm.13103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 12/28/2016] [Indexed: 01/08/2023] Open
Abstract
The present study was designed to investigate whether large conductance Ca2+‐activated K+ (BK) channels were regulated by epidermal growth factor (EGF) receptor (EGFR) tyrosine kinase. BK current and channel tyrosine phosphorylation level were measured in BK‐HEK 293 cells expressing both functional α‐subunits and the auxiliary β1‐subunits using electrophysiology, immunoprecipitation and Western blotting approaches, respectively, and the function of rat cerebral basilar arteries was determined with a wire myography system. We found that BK current in BK‐HEK 293 cells was increased by the broad spectrum protein tyrosine kinase (PTK) inhibitor genistein and the selective EGFR tyrosine kinase inhibitor AG556, one of the known tyrphostin. The effect of genistein or AG556 was antagonized by the protein tyrosine phosphatase (PTP) inhibitor orthovanadate. On the other hand, orthovanadate or EGF decreased BK current, and the effect was counteracted by AG556. The tyrosine phosphorylation level of BK channels (α‐ and β1‐subunits) was increased by EGF and orthovanadate, while decreased by genistein and AG556, and the reduced tyrosine phosphorylation of BK channels by genistein or AG556 was reversed by orthovanadate. Interestingly, AG556 induced a remarkable enhancement of BK current in rat cerebral artery smooth muscle cells and relaxation of pre‐contracted rat cerebral basilar arteries with denuded endothelium, and these effects were antagonized by the BK channel blocker paxilline or orthovanadate. These results demonstrate that tyrosine phosphorylation of BK channels by EGFR kinase decreases the channel activity, and inhibition of EGFR kinase by AG556 enhances the channel activity and dilates rat cerebral basilar arteries.
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Affiliation(s)
- Yan Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Hai-Ying Sun
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Ying-Guang Liu
- Institute of Basic Medical Sciences, Xi'an Medical University, Xi'an, Shaanxi, China
| | - Zheng Song
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Gang She
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Guo-Sheng Xiao
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Yan Wang
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Gui-Rong Li
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Xiu-Ling Deng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.,Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
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Dimitrova P, Ivanovska N. Tyrphostin AG-490 inhibited the acute phase of zymosan-induced inflammation. Int Immunopharmacol 2008; 8:1567-77. [DOI: 10.1016/j.intimp.2008.06.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Revised: 06/26/2008] [Accepted: 06/30/2008] [Indexed: 01/07/2023]
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Mukhopadhyay I, Sausville EA, Doroshow JH, Roy KK. Molecular mechanism of adaphostin-mediated G1 arrest in prostate cancer (PC-3) cells: signaling events mediated by hepatocyte growth factor receptor, c-Met, and p38 MAPK pathways. J Biol Chem 2006; 281:37330-44. [PMID: 16956884 DOI: 10.1074/jbc.m605569200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Adaphostin (NSC680410), a small molecule congener of tyrphostin AG957, has been demonstrated previously to have significant anti-proliferative effects in several leukemia models. However, this effect of adaphostin in adherent cells/solid tumor models has not been examined. In this study, we investigated the anti-proliferative effects of adaphostin in the human prostate cancer cell line PC-3. Specifically, we explored the potential molecular mechanism(s) by which adaphostin elicits its anti-proliferative effect(s). We demonstrate that adaphostin inhibits the proliferation of PC-3 cells by inducing a G(1) phase cell cycle arrest. This adaphostin-induced G(1) arrest was associated with an increase in the expression of p21 and p27 and a decrease in the expression of G(1)-specific cyclins (cyclin A, D1, and D3) and cyclin-dependent kinases 4 and 6. Consequently, a dramatic decrease in the phosphorylation of retinoblastoma protein was also observed. Additionally, we found that adaphostin treatment induced a decrease in the phosphorylation of nucleophosmin, a major nuclear phosphoprotein, and that this decreased phosphorylation was a result of the p21- and p27-mediated inactivation of cyclin E-cyclin-dependent kinase 2 complex kinase activity. Furthermore, we have determined that the adaphostin-mediated cell cycle arrest of PC-3 cells is dependent upon activation of the p38 MAPK. We also demonstrate that the hepatocyte growth factor receptor-c-Met is involved in the adaphostin-mediated signaling events that regulate p38 MAPK. Taken together, these results identify for the first time a signaling cascade of adaphostin-mediated G(1) phase-specific cell cycle arrest in PC-3 cells. These findings suggest that the tyrphostin member has a broader spectrum of activity than originally predicted.
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Affiliation(s)
- Indranil Mukhopadhyay
- Laboratory of Clinical Trials Unit, Division of Cancer Treatment and Diagnosis, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA
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