Emma Villa-Moruzzi1. 1. Department of Experimental Pathology, via Roma 55, University of Pisa, 56126 Pisa, Italy. emma.villa@med.unipi.it
Abstract
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 cross-talk between HER2 and the motility machinery.
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 cross-talk between HER2 and the motility machinery.
Authors: Alicia R Berard; John P Cortens; Oleg Krokhin; John A Wilkins; Alberto Severini; Kevin M Coombs Journal: PLoS One Date: 2012-12-11 Impact factor: 3.240