Increased intracellular Cl- concentration by activating FAK promotes airway epithelial BEAS-2B cells proliferation and wound healing.

An increase in intracellular Cl- concentration ([Cl-]i) may be a general response of airway epithelial cells to various stimuli and may participate in some basic cellular functions. However, whether the basic functional activities of cells, such as proliferation and wound healing, are related to Cl- activities remains unclear. This study aimed to investigate the effects and potential mechanisms of [Cl-]i on the proliferation and wound healing ability of airway epithelial BEAS-2B cells. BEAS-2B cells were treated with four Cl- channel inhibitors (T16Ainh-A01, CFTRinh-172, CaCCinh-A01, and IAA-94), and the Cl- fluorescence probe N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide was used. Results showed that all Cl- channel inhibitors could increase [Cl-]i in BEAS-2B cells. The increased [Cl-]i induced by Cl- channel inhibitors or clamping [Cl-]i at high levels enhanced the phosphorylation of focal adhesion kinase (FAK) and subsequently promoted the proliferation and wound healing ability of BEAS-2B cells. By contrast, the FAK inhibitor PF573228 abrogated these effects induced by the increased [Cl-]i. FAK also activated the PI3K/AKT signaling pathway. In conclusion, increased [Cl-]i promotes the proliferation and wound healing ability of BEAS-2B cells by activating FAK to activate the PI3K/AKT signaling pathway. Intracellular Cl- may act as a signaling molecule to regulate the proliferation and wound healing ability of airway epithelial cells.