Vimentin regulates EMT induction by Slug and oncogenic H-Ras and migration by governing Axl expression in breast cancer

Abstract

Epithelial-to-mesenchymal transition (EMT) is a critical event in the progression toward cancer metastasis. The intermediate filament protein vimentin is an important marker of EMT and a requisite regulator of mesenchymal cell migration. However, it is not known how vimentin functionally contributes to cancer cell invasion. Here, we report that ectopic expression of oncogenic H-Ras-V12G and Slug induces vimentin expression and migration in pre-malignant breast epithelial cells. Conversely, vimentin expression is necessary for Slug-or H-Ras-V12G-induced EMT-associated migration. Furthermore, silencing of vimentin in breast epithelial cells results in specific changes in invasiveness-related gene expression including upregulation of RAB25 (small GTPase Rab25) and downregulation of AXL (receptor tyrosine kinase Axl), PLAU (plasminogen activator, urokinase) and ITGB4 (integrin b4-subunit). Importantly, gene expression profiling analyses reveal that vimentin expression correlates positively/ negatively with these genes also in multiple breast cancer cell lines and breast cancer patient samples. Focusing on the tyrosine kinase Axl, we show that induction of vimentin by EMT is associated with upregulation of Axl expression and that Axl enhances the migratory activity of pre-malignant breast epithelial cells. Using null and knock-down cells and overexpression models, we also show that regulation of breast cancer cell migration in two-and three-dimensional matrices by vimentin is Axldependent and that Axl functionally contributes to lung extravasation of breast cancer cells in mice. In conclusion, our data show that vimentin functionally contributes to EMT and is required for induction of Axl expression. Moreover, these results provide a molecular explanation for vimentin-dependent cancer cell migration during EMT by identifying Axl as a key proximal component in this process.

Targeting Integrin-Linked Kinase Suppresses Invasion and Metastasis through Downregulation of Epithelial-to-Mesenchymal Transition in Renal Cell Carcinoma

“…Recent studies showed that vimentin also contributes functionally to EMT phenotypes including cell migration and invasion. This suggests that ILK plays a critical role in directly regulating EMT signals, as well as mediating EMT signals to reorganization of the cytoskeleton in RCC cells (36,37). Our data show that vimentin expression is regulated by ILK expression, which suggests that ILK regulates the EMT in RCC in various ways.…”

“…ILK silencing inhibited PARP-1 binding to SIRE, and PARP-1 silencing decreased both Zeb1 and Snail, which resulted in the upregulation of E-cadherin (35). Vimentin, the intermediate filament protein, is an important marker of the EMT and a requisite regulator of mesenchymal cell migration (36). Recent studies showed that vimentin also contributes functionally to EMT phenotypes including cell migration and invasion.…”

Mutant p53 drives invasion in breast tumors through up-regulation of miR-155

“…Our findings are consistent with a similar role for ZNF652 as a suppressor of breast cancer cell invasion. We demonstrate that ZNF652 directly represses TGFB1, TGFB2, TGFBR2, EGFR, SMAD2 and VIM; genes that have all been previously implicated in the promotion of mesenchymal transformation and invasion (6,(31)(32)(33)(34). As such, we have defined a new role for ZNF652 as a master regulator of the EMT gene network.…”

Nonmuscle myosin IIB regulates epicardial integrity and epicardium-derived mesenchymal cell maturation

“…An increased expression of the intermediate filament vimentin is another indication of mesenchymal acquisition during EMT (Morabito et al, 2001;Vuoriluoto et al, 2011). The defect in mesenchymal gene expression is further demonstrated in the B WT-1 /B WT-1 compact myocardium in vivo as evaluated by vimentin expression.…”