Cyclic AMP-mediated inhibition of cell growth by prostaglandin D2 in a fibroblastic cell line (EBTr).
We have recently reported that prostaglandin D2 (PGD2) specifically elevates the intracellular cyclic AMP (cAMP) level in a fibroblastic cell line derived from bovine embryonic trachea (EBTr) (K. Sugama, T. Tanaka, H. Yokohama, M. Negishi, H. Hayashi, S. Ito, and O. Hayaishi, Biochim. Biophys. Acta, 1011: 75-80, 1989). Since the in vitro and in vivo inhibitory effects of PGD2 on cell growth are attributed to the dehydrate product 9-deoxy-delta 9,12-13,14-dihydro-PGD2 (delta 12-PGJ2), the role of cAMP as a mediator of PGD2-induced cell growth has been questioned. In this study we investigated the effects of PGD2 on cAMP level, DNA synthesis, and c-myc expression using EBTr cells growth-arrested by serum starvation. Quiescent EBTr cells synchronously resumed [3H]thymidine incorporation at 12 h after the addition of serum, an incorporation which ended at 21 h. PGD2 at 1 microM inhibited approximately 30% incorporation without any delay of initiation, and it also caused a rapid increase in the cAMP level at a maximum of 10 min. The inhibition of [3H]thymidine incorporation was increased 40-45% by 5 microM 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor. The expression of c-myc mRNA induced by serum at 1-4 h was also inhibited by PGD2. Time-course studies support the association between the reduction of c-myc expression and the successive inhibition of DNA synthesis by PGD2. The dose dependency of PGD2 for these three processes correlated well with each other, and the effects were evident at as low as 10 nM and specific for PGD2.(ABSTRACT TRUNCATED AT 250 WORDS)
Okuda-Ashitaka
E
E
Department of Cell Biology, Osaka Bioscience Institute, Suita, Japan.
Negishi
M
M
Sugama
K
K
Hatanaka
M
M
Ito
S
S
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D001769:Blood; D002417:Cattle; D002455:Cell Division; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts; D015870:Gene Expression; D016259:Genes, myc; D007700:Kinetics; D015230:Prostaglandin D2 / Q000494:pharmacology*; D013936:Thymidine / Q000378:metabolism
D005576:Colforsin; D004247:DNA; D000242:Cyclic AMP; D015230:Prostaglandin D2; D015056:1-Methyl-3-isobutylxanthine; D013936:Thymidine