Angerman-Stewart J A, Eling T E, Glasgow W C
Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
Arch Biochem Biophys. 1995 Apr 20;318(2):378-86. doi: 10.1006/abbi.1995.1243.
Metabolites of arachidonic acid and linoleic acid can serve as regulators of the epidermal growth factor signal transduction system in Syrian hamster embryo (SHE) fibroblasts. We have now investigated the possible role of these lipids in modulating the signal transduction of basic fibroblast growth factor (bFGF), a potent mitogen to SHE fibroblasts. The addition of bFGF (0.1 to 1.0 ng/ml) to serum-deprived SHE cells stimulated a six- to sevenfold increase in the incorporation of thymidine into DNA. Structural analysis indicated that bFGF stimulated the metabolism of exogenous and endogenous arachidonic acid to primarily PGE2, PGF2 alpha, and PGD2, with lesser amounts of uncharacterized prostaglandins observed. The metabolism of linoleic acid in SHE cells was not affected by bFGF. bFGF stimulated the expression of the inducible form of prostaglandin H synthase (PGHS-2) as determined by Northern analysis using murine PGHS-2 cDNA as the probe. PGHS-2 protein in the SHE cells was also increased by bFGF as determined by Western analysis using antibodies specific for PGHS-2. Levels of the constitutive (PGHS-1) enzyme and mRNA were not altered by bFGF. Preincubation of the cells with 1-2 microM dexamethasone significantly inhibited bFGF-stimulated expression of PGHS-2 protein and mRNA. Dexamethasone potently inhibited bFGF induced mitogenesis in these cells. Pretreatment of SHE cells with indomethacin inhibited bFGF-dependent mitogenesis, as well as endogenously produced PGE2. The data suggests that regulation of PGHS-2 expression may be an element of the bFGF mitogenic signal transduction pathway.
花生四烯酸和亚油酸的代谢产物可作为叙利亚仓鼠胚胎（SHE）成纤维细胞中表皮生长因子信号转导系统的调节剂。我们现在研究了这些脂质在调节碱性成纤维细胞生长因子（bFGF，一种对SHE成纤维细胞有强大促有丝分裂作用的因子）信号转导中的可能作用。向血清饥饿的SHE细胞中添加bFGF（0.1至1.0 ng/ml）可刺激胸苷掺入DNA的量增加6至7倍。结构分析表明，bFGF刺激外源性和内源性花生四烯酸主要代谢为PGE2、PGF2α和PGD2，同时观察到少量未鉴定的前列腺素。bFGF不影响SHE细胞中亚油酸的代谢。通过使用鼠PGHS-2 cDNA作为探针的Northern分析确定，bFGF刺激了诱导型前列腺素H合酶（PGHS-2）的表达。通过使用对PGHS-2特异的抗体进行Western分析确定，bFGF也增加了SHE细胞中PGHS-2蛋白的水平。组成型（PGHS-1）酶和mRNA的水平未被bFGF改变。用1-2 microM地塞米松预孵育细胞可显著抑制bFGF刺激的PGHS-2蛋白和mRNA的表达。地塞米松强烈抑制这些细胞中bFGF诱导的有丝分裂。用吲哚美辛预处理SHE细胞可抑制bFGF依赖的有丝分裂以及内源性产生的PGE2。数据表明，PGHS-2表达的调节可能是bFGF促有丝分裂信号转导途径的一个要素。
