Evaluation of beta-adrenergic receptor subtypes in the human prostate cancer cell line-LNCaP.
The present study was undertaken to determine the effects of catecholamines, agonists, and antagonists of beta-adrenergic receptors (AR) in the LNCaP cell line. Changes in cellular cyclic adenosine-3',5'-monophosphate (cAMP) levels were quantified by the use of a 6 cAMP response element (CRE)-luciferase reporter gene assay. LNCaP cells were transiently transfected with this gene construct, incubated in 96-well microtiter plates for 24 hr, and then treated with beta-AR agonists and/or antagonists for 4 hr. The rank order of potency for catecholamines and known beta-AR agonists was terbutaline(3.31 nM)>isoproterenol(8.31 nM)> or =fenoterol(15 nM)=epinephrine(16.2 nM)>norepinephrine(77.5 nM)>BRL-37344 [(R(*),R(*))-(+/-)4-[2-[(2-(3-chlorophenyl)-2-hydroxyethyl)amino]propyl]phenoxy acetic acid, sodium salt] (1000 nM)>dobutamine(1770 nM)>CGP12177 (4-[3-[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazole-2-one hydrochloride) (inactive). The non-selective beta(1)-/-beta(2)-AR antagonists; propranolol and CGP 12177, at 10(-7)M, inhibited luciferase activity induced by these agonists by 80-96%. Propranolol blocked isoproterenol-induced luciferase responses in a competitive manner (K(B)=1.4 nM). In addition, isoproterenol-activated luciferase expression was blocked more potently by ICI 118,551 [(+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethy) amino]-2-butanol], a beta(2)-AR antagonist than by ICI 89,406 [(+/-)-N-[2-[3-(2-cyanophenoxy-)]-2-hydroxypropylamino]ethyl-N-phenylurea], a beta(1)-AR antagonist, giving K(B) values of 1.07 and 161nM, respectively. These results suggest that the beta(2)-AR is the major subtype mediating catecholamine-induced cAMP changes in LNCaP cells.
Department of Pharmacology, The University of Mississippi, University, MS 38677-1848, USA. swamy@olemiss.edu
Rangaswamy
R
Nagmani
David S
DS
Pasco
Ruben D
RD
Salas
Dennis R
DR
Feller
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D011943:Receptors, Adrenergic, beta / Q000145:classification* / Q000187:drug effects; D014407:Tumor Cells, Cultured
D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta