Properties and expression of acid-sensing ion channels in ACC-2 cells

Objectives: To investigate the electrophysiological properties and the expression of acid-sensing ion channels (ASICs) in cultured human salivary adenoid cystic carcinoma cell (ACC-2) in vitro. Methods: cell culture, whole-cell patch clamp, RT-PCR and western-blot. Results: Exogenous application of acidic solution induced an inward steady current in ACC-2 cells. The steady current was sensitive to the extracellular proton with a response threshold of pH 4.5-4.0, reversal potential close to Na+ equilibrium potential, + 39.45 ± 2.5 mV (n = 12, student's t-test). Furthermore, it had a characteristic of acid-sensing ion channels (ASICs) as demonstrated by its sensitivity to amiloride, the antagonist of ASICs. All these electrophysiological and pharmacological properties of the proton-induced current are consistent with the channel of ASIC2a. Subsequent western-blot studies together with our RT-PCR experiments strongly suggested the expression of ASIC2a in ACC-2 cells. Conclusion: We contribute a new method to research the characteristics of tumor cells(ACC-2)using whole-cell patch clamp technique. The functional ASIC2a was expressed in ACC-2 cells. As ASIC2a is permeable to Na+ and K+, which are known involved in apoptosis, the expressed ASIC2a may also contribute to the pathological progress of ACC-2 cells and may offer a novel pharmacological target for the therapeutic invention of carcinoma.