Biomaterial Database

P2u purinoceptor modulation of intracellular Ca2+ in a human lung adenocarcinoma cell line: down-regulation of Ca2+ influx by protein kinase C. 1996

M T Clunes, and P J Kemp

Department of Child Health, University of Dundee, Ninewells Hospital, UK.

The human lung small cell adenocarcinoma cell line, A549, demonstrates a concentration-dependent rise in [Ca2+]i in response to extracellular nucleotides. The cells show Ca2+ mobilization on addition of various nucleotides, with an order of agonist potency: UTP > or = ATP > ADP > ADP beta S > AMP; adenosine is ineffective. The EC50 values for UTP and ATP are 12.5 +/- 0.4 microM and 18.9 +/- 0.5 microM, respectively. Together, these results are strongly indicative of the P2U subclass being the major nucleotide receptor expressed in these cells. The Ca2+ response was typically biphasic consisting of an initial spike, representing release of Ca2+ from internal stores, and a subsequent plateau representing Ca2+ influx. The majority of cells showed an agonist-induced Ca2+ increase that was unaffected by pretreatment with the Ca(2+)-ATPase inhibitors 2,5-di(tert-butyl)1,4-benzohydroquinone or thapsigargin. Caffeine did not raise [Ca2+]i above basal levels and applied in conjunction with nucleotide did not attenuate the agonist-mediated response. The Ca2+ influx was sensitive to protein kinase C, and agonist addition in the presence of a protein kinase C inhibitor, D-erythrosphingosine, produced a significantly potentiated Ca2+ influx. Furthermore, agonist-mediated Ca2+ influx was abolished in the presence of a protein kinase C activator, phorbol 12,13-dibutyrate. It is concluded that these cells posses a functional P2U receptor that, upon activation, causes Ca2+ mobilization from TBQ and thapsigargin insensitive stores followed by protein kinase C regulated Ca2+ influx.

UI	MeSH Term	Description	Entries
D008175	Lung Neoplasms	Tumors or cancer of the LUNG.	Cancer of Lung,Lung Cancer,Pulmonary Cancer,Pulmonary Neoplasms,Cancer of the Lung,Neoplasms, Lung,Neoplasms, Pulmonary,Cancer, Lung,Cancer, Pulmonary,Cancers, Lung,Cancers, Pulmonary,Lung Cancers,Lung Neoplasm,Neoplasm, Lung,Neoplasm, Pulmonary,Pulmonary Cancers,Pulmonary Neoplasm
D010726	Phosphodiesterase Inhibitors	Compounds which inhibit or antagonize the biosynthesis or actions of phosphodiesterases.	Phosphodiesterase Antagonists,Phosphodiesterase Inhibitor,Phosphoric Diester Hydrolase Inhibitors,Antiphosphodiesterases,Inhibitor, Phosphodiesterase
D011493	Protein Kinase C	An serine-threonine protein kinase that requires the presence of physiological concentrations of CALCIUM and membrane PHOSPHOLIPIDS. The additional presence of DIACYLGLYCEROLS markedly increases its sensitivity to both calcium and phospholipids. The sensitivity of the enzyme can also be increased by PHORBOL ESTERS and it is believed that protein kinase C is the receptor protein of tumor-promoting phorbol esters.	Calcium Phospholipid-Dependent Protein Kinase,Calcium-Activated Phospholipid-Dependent Kinase,PKC Serine-Threonine Kinase,Phospholipid-Sensitive Calcium-Dependent Protein Kinase,Protein Kinase M,Calcium Activated Phospholipid Dependent Kinase,Calcium Phospholipid Dependent Protein Kinase,PKC Serine Threonine Kinase,Phospholipid Sensitive Calcium Dependent Protein Kinase,Phospholipid-Dependent Kinase, Calcium-Activated,Serine-Threonine Kinase, PKC
D002110	Caffeine	A methylxanthine naturally occurring in some beverages and also used as a pharmacological agent. Caffeine's most notable pharmacological effect is as a central nervous system stimulant, increasing alertness and producing agitation. It also relaxes SMOOTH MUSCLE, stimulates CARDIAC MUSCLE, stimulates DIURESIS, and appears to be useful in the treatment of some types of headache. Several cellular actions of caffeine have been observed, but it is not entirely clear how each contributes to its pharmacological profile. Among the most important are inhibition of cyclic nucleotide PHOSPHODIESTERASES, antagonism of ADENOSINE RECEPTORS, and modulation of intracellular calcium handling.	1,3,7-Trimethylxanthine,Caffedrine,Coffeinum N,Coffeinum Purrum,Dexitac,Durvitan,No Doz,Percoffedrinol N,Percutaféine,Quick-Pep,Vivarin,Quick Pep,QuickPep
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004791	Enzyme Inhibitors	Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.	Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000230	Adenocarcinoma	A malignant epithelial tumor with a glandular organization.	Adenocarcinoma, Basal Cell,Adenocarcinoma, Granular Cell,Adenocarcinoma, Oxyphilic,Adenocarcinoma, Tubular,Adenoma, Malignant,Carcinoma, Cribriform,Carcinoma, Granular Cell,Carcinoma, Tubular,Adenocarcinomas,Adenocarcinomas, Basal Cell,Adenocarcinomas, Granular Cell,Adenocarcinomas, Oxyphilic,Adenocarcinomas, Tubular,Adenomas, Malignant,Basal Cell Adenocarcinoma,Basal Cell Adenocarcinomas,Carcinomas, Cribriform,Carcinomas, Granular Cell,Carcinomas, Tubular,Cribriform Carcinoma,Cribriform Carcinomas,Granular Cell Adenocarcinoma,Granular Cell Adenocarcinomas,Granular Cell Carcinoma,Granular Cell Carcinomas,Malignant Adenoma,Malignant Adenomas,Oxyphilic Adenocarcinoma,Oxyphilic Adenocarcinomas,Tubular Adenocarcinoma,Tubular Adenocarcinomas,Tubular Carcinoma,Tubular Carcinomas
D000244	Adenosine Diphosphate	Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.	ADP,Adenosine Pyrophosphate,Magnesium ADP,MgADP,Adenosine 5'-Pyrophosphate,5'-Pyrophosphate, Adenosine,ADP, Magnesium,Adenosine 5' Pyrophosphate,Diphosphate, Adenosine,Pyrophosphate, Adenosine
D000249	Adenosine Monophosphate	Adenine nucleotide containing one phosphate group esterified to the sugar moiety in the 2'-, 3'-, or 5'-position.	AMP,Adenylic Acid,2'-AMP,2'-Adenosine Monophosphate,2'-Adenylic Acid,5'-Adenylic Acid,Adenosine 2'-Phosphate,Adenosine 3'-Phosphate,Adenosine 5'-Phosphate,Adenosine Phosphate Dipotassium,Adenosine Phosphate Disodium,Phosphaden,2' Adenosine Monophosphate,2' Adenylic Acid,5' Adenylic Acid,5'-Phosphate, Adenosine,Acid, 2'-Adenylic,Acid, 5'-Adenylic,Adenosine 2' Phosphate,Adenosine 3' Phosphate,Adenosine 5' Phosphate,Dipotassium, Adenosine Phosphate,Disodium, Adenosine Phosphate,Monophosphate, 2'-Adenosine,Phosphate Dipotassium, Adenosine,Phosphate Disodium, Adenosine