Környei J L, Li X, Lei Z M, Rao C V
Department of Obstetrics and Gynecology, University of Louisville, School of Medicine, Kentucky 40492, USA.
J Endocrinol. 1995 Aug;146(2):261-70. doi: 10.1677/joe.0.1460261.
The present study investigated the mechanisms involved in the mitogenic action of epidermal growth factor (EGF) in cultured human myometrial smooth muscle cells. The cells contained EGF/transforming growth factor-alpha (TGF-alpha) receptors as well as EGF and TGF-alpha mRNA transcripts and the corresponding proteins. Culturing with human EGF resulted in concentration- and time-dependent increases in cell density. The maximal increase was seen at 1 nM followed by a decrease to control levels at 100 nM EGF. The EGF increased cell density from 4 to 8 days followed by a plateau coinciding with the cells reaching confluence. EGF treatment concomitantly decreased the average size of cells. TGF-alpha mimicked EGF and there was no synergism between the two, suggesting a common mechanism of action. Although the presence of 10% fetal bovine serum enhanced overall cell growth, it was not required for EGF and TGF-alpha action. The receptor antibody, which is directed against the extracellular domain and can inhibit ligand binding to the receptors, dramatically inhibited the basal cell growth and exogenous EGF reversed the antibody effect. While TGF-alpha antibody was only marginally effective, EGF antibody had no effect on basal cell growth. Lavendustin (a tyrosine kinase inhibitor), calphostin (a protein kinase C inhibitor), but not H-89 (a protein kinase A inhibitor), inhibited EGF action. Indomethacin, a cyclo-oxygenase inhibitor, completely inhibited, whereas nordihydroguaiaretic acid, a lipoxygenase inhibitor, slightly inhibited EGF action. While estradiol-17 beta modestly inhibited basal as well as EGF-stimulated myometrial smooth muscle cell density, progesterone had no effect. In summary, mitogenic action of EGF in human myometrial smooth muscle cells does not require serum components and it involves tyrosine kinase and protein kinase C signaling and eicosanoids from the cyclooxygenase pathway of arachidonic acid metabolism.
本研究调查了表皮生长因子（EGF）在培养的人子宫肌层平滑肌细胞中促有丝分裂作用的相关机制。这些细胞含有EGF/转化生长因子-α（TGF-α）受体以及EGF和TGF-α的mRNA转录本及相应蛋白质。用人EGF培养导致细胞密度呈浓度和时间依赖性增加。在1 nM时可见最大增加，随后在100 nM EGF时降至对照水平。EGF在4至8天增加细胞密度，随后在细胞达到汇合时出现平台期。EGF处理同时降低了细胞的平均大小。TGF-α模拟EGF，两者之间没有协同作用，提示存在共同作用机制。虽然10%胎牛血清的存在增强了总体细胞生长，但EGF和TGF-α发挥作用并不需要它。针对细胞外结构域且能抑制配体与受体结合的受体抗体显著抑制基础细胞生长，外源性EGF可逆转抗体效应。而TGF-α抗体仅具有微弱作用，EGF抗体对基础细胞生长无影响。拉文杜斯汀（一种酪氨酸激酶抑制剂）、钙泊三醇（一种蛋白激酶C抑制剂）而非H-89（一种蛋白激酶A抑制剂）抑制EGF作用。环氧化酶抑制剂吲哚美辛完全抑制，而脂氧合酶抑制剂去甲二氢愈创木酸轻微抑制EGF作用。虽然雌二醇-17β适度抑制基础及EGF刺激的子宫肌层平滑肌细胞密度，但孕酮无作用。总之，EGF在人子宫肌层平滑肌细胞中的促有丝分裂作用不需要血清成分，涉及酪氨酸激酶和蛋白激酶C信号传导以及花生四烯酸代谢环氧化酶途径产生的类花生酸。
