TRPC1-STIM1 activation modulates transforming growth factor ?-induced epithelial-to-mesenchymal transition.

ABSTRACT: Activation of Epithelial-to-Mesenchymal Transition (EMT) is important for tumor metastasis. Although growth factors such as TGF? and EGF have been shown to induce EMT in breast epithelial cells, the mechanism resulting in migration is not well understood. Herein, we provide evidence that Ca2+ entry into the cell, especially upon store-depletion, plays an important role in TGF?-induced EMT by promoting cellular migration and potentially leading to metastasis. The increased migration by TGF? in non-cancerous cells was due to the loss of E-cadherin along with a subsequent increase in N-cadherin levels. Importantly, TGF?-treatment increases store-mediated Ca2+ entry, which was essential for the activation of calpain leading to the loss of E-cadherin and MMP activation. Inhibition of Ca2+ entry by using Ca2+ channel blocker SKF-96365, significantly decreased Ca2+ entry, decreased TGF?-induced calpain activation, and suppressed the loss of E-cadherin along with inhibiting cell migration. Furthermore, TRPC1 function as an endogenous Ca2+ entry channel and silencing of either TRPC1 or its activator, STIM1, significantly decreased TGF? induced Ca2+ entry, inhibited TGF?-mediated calpain activation and cell migration. In contrast, overexpression of TRPC1 showed increased Ca2+ entry and promoted TGF?-mediated cell migration. Moreover, increased TRPC1 expression was observed in ductal carcinoma cells. Together these results suggest that disrupting Ca2+ influx via TRPC1/STIM1 mechanism reduces calpain activity, which could restore intercellular junction proteins thereby inhibiting EMT induced motility.

SUBMITTER: Schaar A 

PROVIDER: S-EPMC5348340 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature