Volume-regulated chloride conductance in the LNCaP human prostate cancer cell line

• Published in: American Journal of Physiology: Cell Physiology Vol. 279; no. 4; pp. C1144 - C1154
• Main Authors: Shuba, Y. M, Prevarskaya, N, Lemonnier, L, Van Coppenolle, F, Kostyuk, P. G, Mauroy, B, Skryma, R
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.10.2000
• Subjects: 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid - pharmacology; 8-Bromo Cyclic Adenosine Monophosphate - pharmacology; Adenosine Triphosphate - metabolism; Anions - metabolism; Anions - pharmacology; Calcium - metabolism; Calcium Channel Blockers - pharmacology; Carcinoma - metabolism; Carcinoma - pathology; Cell Membrane Permeability - drug effects; Chloride Channels - metabolism; Electric Stimulation; Humans; Hypotonic Solutions - pharmacology; Ion Transport - drug effects; Life Sciences; Male; Membrane Potentials - drug effects; Nitrobenzoates - pharmacology; Patch-Clamp Techniques; Potassium - metabolism; Prostatic Neoplasms - metabolism; Prostatic Neoplasms - pathology; Protein-Tyrosine Kinases - antagonists & inhibitors; Substrate Specificity; Tetraethylammonium - pharmacology; Tumor Cells, Cultured; Verapamil - pharmacology
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.2000.279.4.c1144

Laboratoire de Physiologie Cellulaire, Institut National de la Santé et de la Recherche Médicale EPI 9938, Université des Sciences et Technologies de Lille, 59655 Villeneuve d'Ascq, France Patch-clamp recordings were used to study ion currents induced by cell swelling caused by hypotonicity in human prostate cancer epithelial cells, LNCaP. The reversal potential of the swelling-evoked current suggested that Cl was the primary charge carrier (termed I Cl,swell ). The selectivity sequence of the underlying volume-regulated anion channels (VRACs) for different anions was Br I  > Cl  > F  > methanesulfonate glutamate, with relative permeability numbers of 1.26, 1.20, 1.0, 0.77, 0.49, and 0.036, respectively. The current-voltage patterns of the whole cell currents as well as single-channel currents showed moderate outward rectification. Unitary VRAC conductance was determined at 9.6 ± 1.8 pS. Conventional Cl channel blockers 5-nitro-2-(3-phenylpropylamino)benzoic acid (100 µM) and DIDS (100 µM) inhibited whole cell I Cl,swell in a voltage-dependent manner, with the block decreasing from 39.6   ± 9.7% and 71.0 ± 11.0% at +50 mV to 26.2 ± 7.2% and 14.5 ± 6.6% at 100 mV, respectively. Verapamil (50 µM), a standard Ca 2+ antagonist and P-glycoprotein function inhibitor, depressed the current by a maximum of 15%. Protein tyrosine kinase inhibitors downregulated I Cl,swell (genistein with an IC 50 of 2.6 µM and lavendustin A by 60 ± 14% at 1 µM). The protein tyrosine phosphatase inhibitor sodium orthovanadate (500 µM) stimulated I Cl,swell by 54 ± 11%. We conclude that VRACs in human prostate cancer epithelial cells are modulated via protein tyrosine phosphorylation. volume-regulated chloride channels; tyrosine kinase; cell volume * Y. M. Shuba and N. Prevarskaya contributed equally to this work.