Volume-regulated chloride conductance in the LNCaP human prostate cancer cell line.
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(-) approximately 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 microM) and DIDS (100 microM) 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 microM), 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 microM and lavendustin A by 60 +/- 14% at 1 microM). The protein tyrosine phosphatase inhibitor sodium orthovanadate (500 microM) stimulated I(Cl,swell) by 54 +/- 11%. We conclude that VRACs in human prostate cancer epithelial cells are modulated via protein tyrosine phosphorylation.
Shuba
Y M
YM
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. phycel@pop.univ-lille1.fr
Prevarskaya
N
N
Lemonnier
L
L
Van Coppenolle
F
F
Kostyuk
P G
PG
Mauroy
B
B
Skryma
R
R
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism; D000838:Anions / Q000378:metabolism / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology; D002463:Cell Membrane Permeability / Q000187:drug effects; D018118:Chloride Channels / Q000378:metabolism*; D004558:Electric Stimulation; D006801:Humans; D007038:Hypotonic Solutions / Q000494:pharmacology; D017136:Ion Transport / Q000187:drug effects; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009579:Nitrobenzoates / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D013379:Substrate Specificity; D019789:Tetraethylammonium / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014700:Verapamil / Q000494:pharmacology
D000838:Anions; D002121:Calcium Channel Blockers; D018118:Chloride Channels; D007038:Hypotonic Solutions; D009579:Nitrobenzoates; D015124:8-Bromo Cyclic Adenosine Monophosphate; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D019789:Tetraethylammonium; D000255:Adenosine Triphosphate; D014700:Verapamil; D011505:Protein-Tyrosine Kinases; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D011188:Potassium; D002118:Calcium