Background: Very little is known about the expression of ion channels in prostate cells (both normal and malignant), and their possible role in physiological and pathological functions. We therefore studied ion conductances and their role in the proliferation of LNCaP cells, an androgen-sensitive human prostate cancer cell line.
Methods: We applied patch-clamp recording techniques for electrophysiological studies, and 3H-thymidine incorporation and protein content assays for cell growth studies.
Results: Only one type of voltage-dependent ion conductance, a potassium K+ conductance, was identified. This current, which was depressed by a rise in intracellular Ca2+, had a high sensitivity to tetraethylammonium (TEA) (with half-block at 2 mM) and was also inhibited by 2 nM alpha-dendrotoxin (DTX) and 20 nM mast-cell degranulating peptide (MCDP). K+ channel inhibitors inhibited [3H]thymidine incorporation and protein content, in a dose-dependent fashion, indicating that K+ channels are involved in cell growth.
Conclusions: We conclude from our findings that the human cancer prostate cell line LNCaP has a new type of K+ channel, likely to play an essential role in the physiology of these cells and, more specifically, in cell proliferation.