[The relation between potassium channel properties and proliferation of human lung adenocarcinoma cells]

Oncogenesis, development, invasion and metastasis of lung cancer are modulated by relative genes of lung cancer, and the expression, deletion or mutation of these genes are regulated by cell membrane signal transduction system and cell membrane ionic channels. The aim of this study is to explore the electrophysiological properties of human lung adenocarcinoma cell line A549 and cell proliferation affected by tetraethylammonium chloride (TEA), one potassium channel blocker, so as to know whether the voltage-gated potassium channels are required for the proliferation of A549 cell line.

Ionic currents were recorded by whole-cell patch-clamp recording technique. The proliferation activity of A549 cells was measured by MTT assay.

Membrane current was observed when cells were held at -70mV and test potentials ranged from -30 to +110mV. The current exhibited properties of voltage-dependent, outward rectification and no or little inactivation over the 500ms voltage pulse. Exposure of tumor cells to 10mmol/L TEA reduced the peak outward potassium current (evoked by depolarization to +110mV) from (1057.52±59.17)pA to (212.26±11.96)pA, the ratio of suppression was 79.92% (P < 0.01). Obvious inhibitive effect of TEA with different concentrations ranged from 20 to 60mmol/L on proliferation activity of the cells was found.

The voltage-gated potassium channels exist in human lung adenocarcinoma cell line A549 and play a great role in proliferation of A549 cells. TEA can inhibit proliferation of A549 cell through blocking the potassium channels and the inhibition is dose-dependent.