J Biomed Res.  2013 Jun;14(2):71-76.

Functional expression of mechanosensitive two-pore domain potassium channel in human bladder carcinoma cells

• Park KS
• Kim Y

Abstract

Bladder cancer is a common cancer in smoking men and may correlate with mechanosensitive potassium channels because the urinary bladder is a stretch sensing organ. Two-pore K+ channels (K2P), such as TASK3 and TREK1, have recently been shown to play a critical role in both cell apoptosis and tumorigenesis. Of the channels, TREK1 can be activated by many physiological stimuli, including polyunsaturated fatty acids, and intracellular pH, hypoxia, and neurotransmitters. Here we attempted to determine whether TREK1 is functionally expressed in bladder cancer 253J cells. K2P channels, including TREK1, TREK2, TASK1, TASK3, and TWIK1, were quantified in cultured human bladder cancer 253J cells using real time quantitative RT-PCR (qRT-PCR) analysis. Among them, TREK1-like channel was recorded at a single channel level using the patch-clamp technique. The TREKl-like channel, with single-channel conductance of ~90 pS at -80 mV, was recorded in symmetrical 150 mM KCl using an excised inside-out patch configuration. The current-voltage relationships were linear and were insensitive to tetraethylammonium. The channel was activated by membrane stretch, free fatty acids, and intracellular acidosis. These results with electrophysiological properties resemble to those of K2P channel, for instance, TREK1. Therefore, we conclude that TREK1 channel is functionally present in bladder cancer 253J cells.

Keyword

two-pore K+ channel; TREK1; bladder cancer 253J cell; patch clamp; single channel recording

MeSH Terms

Acidosis
Anoxia
Apoptosis
Cell Transformation, Neoplastic
Fatty Acids, Nonesterified
Fatty Acids, Unsaturated
Humans*
Hydrogen-Ion Concentration
Male
Membranes
Neurotransmitter Agents
Patch-Clamp Techniques
Potassium Channels*
Potassium*
Smoke
Smoking
Tetraethylammonium
Urinary Bladder Neoplasms
Urinary Bladder*
Fatty Acids, Nonesterified
Fatty Acids, Unsaturated
Neurotransmitter Agents
Potassium
Potassium Channels
Smoke
Tetraethylammonium