Mechanisms of P2 receptor-evoked DNA synthesis in thyroid FRTL-5 cells.
The expression of the P2 receptors and their functional responses were studied in rat thyroid FRTL-5 cells. RT-PCR analysis revealed transcripts for the G protein-coupled P2Y(2), P2Y(4) and P2Y(6) receptors, and for the transmitter-gated ion channel P2X(3), P2X(4) and P2X(5) subunits. In Fura-2-loaded cells, UTP, ATP, ATPgammaS or UDP increased [Ca(2+)](i), and behaved as potent full agonists, while 2-Methylthio-ATP (2-MeSATP), alpha,beta-methylene-ATP (alpha,beta-meATP) and pure ADP were weak agonists. The agonist-mediated [Ca(2+) ](i) increases were diminished in Ca(2+) -free buffer, and by pertussis toxin (PTX) or suramin treatments. ATP, UTP, UDP and ATPgammaS increased (3)H-thymidine incorporation into DNA and expression of the protooncogenes c-Fos and c-Jun, while 2-MeSATP was ineffective, and alpha,beta-meATP gave a response only at 100-microM dose. The ATP-stimulated expression of c-Fos and c-Jun was dependent on Ca(2+), and protein kinase C, but not on calmodulin or Ca(2+)/calmodulin-dependent protein kinase II. Extracellular signal-regulated kinases (ERK1 and ERK2) are also involved as the MEK inhibitor, PD98059, reduced both ATP-evoked (3)H-thymidine incorporation and c-Fos and c-Jun expression. These results indicate that multiple P2Y receptor subtypes and at least the P2X(5) subtype are functionally expressed in FRTL-5 cells, and that nucleotides acting via P2 receptors are involved in the regulation of DNA-synthesis.
Department of Biosciences, Division of Animal Physiology, University of Helsinki.
E
E
Ekokoski
T E
TE
Webb
J
J
Simon
K
K
Törnquist
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D017931:DNA Primers; D004261:DNA Replication / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D017781:Genes, Immediate-Early / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D013936:Thymidine / Q000378:metabolism / Q000494:pharmacology; D013961:Thyroid Gland / Q000166:cytology*; D014158:Transcription, Genetic / Q000502:physiology; D014316:Tritium; D014530:Uridine Diphosphate / Q000494:pharmacology; D014544:Uridine Triphosphate / Q000494:pharmacology
D017931:DNA Primers; D004791:Enzyme Inhibitors; D005419:Flavonoids; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D018048:Receptors, Purinergic P2; D014316:Tritium; C022571:adenosine 5'-O-(3-thiotriphosphate); D014530:Uridine Diphosphate; D000255:Adenosine Triphosphate; D004247:DNA; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium; D014544:Uridine Triphosphate; D013936:Thymidine