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Analytical Cellular Pathology
Volume 34 (2011), Issue 3, Pages 101-112

Tyrosine Phosphatases in the HER2-Directed Motility of Ovarian Cancer Cells: Involvement of PTPN12, ERK5 and FAK

Emma Villa-Moruzzi

Department of Experimental Pathology, via Roma 55, University of Pisa, 56126 Pisa, Italy

Copyright © 2011 Hindawi Publishing Corporation and the authors. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background: HER2 activation in tumours supports multiple signalling pathways, including those regulating invasion and metastasis. Among the involved genes, Tyrosine and Dual Specificity Phosphatases (PTPs and DSPs) may play a relevant, though not completely clear role. Methods: HER2 was silenced in ovarian SKOV-3 cells, a genome-wide expression analysis of PTPs and DSPs was performed, the effects on cell motility were analysed and compared with those of PTPN12-silencing, focusing on FAK. Results: HER2-silencing altered the expression of 4 PTPs and 6 DSPs; PTPN12 displayed also 3-4-fold protein increase. Conversely, PTPN12-silencing enhanced migration, suggesting that PTPN12 down-modulation by HER2 favours motility. HER2-silencing inactivated FAK, in quiescent and migrating cells, involving FAK dephosphorylation at Y397 and S910. Conversely, in PTPN12-silenced cells FAK activity was close to control, altogether suggesting that PTPN12 targets Y397. As regards to S910, cell-treatment with the MEK inhibitor UO126 and ERK5-silencing indicated its targeting by ERK5. Loss of pS910 and decreased ERK5 kinase activity in HER2-silenced cells confirmed their control by HER2. Conclusions: The results indicate the contribution of PTPN12, targeting FAK Y397, and ERK5, targeting FAK S910, to the HER2-driven cell motility, thus depicting new aspects of the complex cross­talk between HER2 and the motility machinery.