Prostaglandin synthase 2 expression in epidermal growth factor-dependent proliferation of mouse keratinocytes.
BALB/c mouse keratinocytes (BALB/MK) are nontumorigenic epithelial cells which are dependent on mouse epidermal growth factor (EGF) for maintaining proliferation in culture. In BALB/MK the oxygenation of both arachidonic acid and linoleic acid was dependent on EGF. EGF stimulated the formation of prostaglandin E2 and prostaglandin F2 alpha from arachidonic acid and 9- and 13-hydroxyoctadecadienoic acid (HODE) from linoleic acid. Analysis of the linoleic acid metabolites determined the ratio of 9-HODE to 13-HODE was approximately 6 to 4, and the 9-HODE was the (R) enantiomer, consistent with metabolism by prostaglandin G/H synthase (PGHS). The formation of these linoleic acid metabolites was sensitive to indomethacin, a PGHS inhibitor. EGF induced the expression of PGHS-2 mRNA after 30 min, which peaked after 1 h, and remained expressed for at least 24 h after the addition of EGF. A less significant increase in the expression of PGHS-1 mRNA occurred 4 h after EGF stimulation. Immunoblot analysis did not detect expression of PGHS-1 protein. However, PGHS-2 protein expression was increased 2 h after EGF exposure and was dependent on EGF. PGHS-2 protein was not transiently expressed as reported with other cell types, but was continually expressed in proliferating cells maintained with EGF at a subconfluent density. Indomethacin significantly attenuated EGF-dependent mitogenesis and cell proliferation. These results suggest that PGHS-2 activity contributes to the proliferative response of BALB/MK to EGF.
Loftin
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Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
Eling
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D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology; D015232:Dinoprostone / Q000096:biosynthesis; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D007213:Indomethacin / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D007328:Insulin; D007527:Isoenzymes; D008041:Linoleic Acids; D012333:RNA, Messenger; D016718:Arachidonic Acid; D004815:Epidermal Growth Factor; D003907:Dexamethasone; D019787:Linoleic Acid; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone; D007213:Indomethacin