Thalacker F W, Nilsen-Hamilton M
J Biol Chem. 1987 Feb 15;262(5):2283-90.
To examine the mechanisms by which transforming growth factors (TGFs) regulate the proliferation of eukaryotic cells, five cell lines, from different species and tissues, were treated with three agents that inhibit DNA synthesis and proliferation: BSC-1 cell-derived growth inhibitor (GI/TGF-beta), platelet-derived transforming growth factor-beta (TGF-beta), and 12-O-tetradecanoylphorbol-13-acetate. The cell lines tested were mink lung CCL 64 epithelial cells, Maloney sarcoma virus-transformed CCL 64.1, monkey kidney BSC-1 epithelial cells, human epidermoid A431 cells, and mouse embryo AKR-2B (clone 84A) cells. All cell lines responded to one or more of these agents by synthesizing and secreting a 48 to 51-kDa protein (IIP48). The TGF-beta s and 12-O-tetradecanoylphorbol-13-acetate had little or no effect on the incorporation of [35S] methionine into other secreted proteins or on the pattern of [35S]methionine-labeled intracellular proteins analyzed by one-dimensional, sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The maximum increase in induction of IIP48 varied from 2-fold to greater than 800-fold compared with the controls and occurred within 6 h of adding GI/TGF-beta to CCL 64 cells. Actinomycin D, alpha-amanitin, or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole selectively decreased both the control and induced levels of IIP48 even after as little as 6 h of incubation. Thus, it appears that IIP48 mRNA turns over rapidly. Induction of IIP48 was dissociated from the inhibition of DNA synthesis by GI/TGF-beta. However, we found that epidermal growth factor and GI/TGF-beta act synergistically to increase the secreted level of IIP48. Others have shown that epidermal growth factor and TGF-beta act synergistically to stimulate growth of cells in agar. IIP48 from CCL 64, BSC-1, and AKR-2B cells is specifically immunoprecipitated by antibody to bovine plasminogen activator inhibitor. We found previously that TGF-beta also inhibits the production of major excreted protein, a thiol protease. It is proposed that TGF-beta is able to promote anchorage-independent growth of untransformed cells because of its ability to inhibit the production of secreted proteases and to increase the production of protease inhibitors.
为研究转化生长因子（TGFs）调控真核细胞增殖的机制，选用了来自不同物种和组织的5种细胞系，用3种抑制DNA合成和增殖的试剂进行处理：BSC - 1细胞衍生生长抑制剂（GI/TGF - β）、血小板衍生转化生长因子 - β（TGF - β）和12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯。所测试的细胞系有貂肺CCL 64上皮细胞、莫洛尼肉瘤病毒转化的CCL 64.1、猴肾BSC - 1上皮细胞、人表皮样A431细胞和小鼠胚胎AKR - 2B（克隆84A）细胞。所有细胞系对这些试剂中的一种或多种产生反应，合成并分泌一种48至51 kDa的蛋白质（IIP48）。TGF - βs和12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯对[35S]甲硫氨酸掺入其他分泌蛋白或对经一维十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳分析的[35S]甲硫氨酸标记的细胞内蛋白模式影响很小或没有影响。与对照相比，IIP48诱导的最大增加倍数从2倍到大于800倍不等，且在向CCL 64细胞添加GI/TGF - β后6小时内出现。放线菌素D、α - 鹅膏蕈碱或5,6 - 二氯 - 1 - β - D - 呋喃核糖基苯并咪唑即使在孵育仅6小时后也选择性地降低了IIP48的对照水平和诱导水平。因此，似乎IIP48 mRNA周转迅速。IIP48的诱导与GI/TGF - β对DNA合成的抑制无关。然而，我们发现表皮生长因子和GI/TGF - β协同作用可增加IIP48的分泌水平。其他人已表明表皮生长因子和TGF - β协同作用可刺激琼脂中细胞的生长。来自CCL 64、BSC - 1和AKR - 2B细胞的IIP48可被抗牛纤溶酶原激活物抑制剂抗体特异性免疫沉淀。我们先前发现TGF - β也抑制主要分泌蛋白（一种巯基蛋白酶）的产生。有人提出，TGF - β能够促进未转化细胞的非锚定依赖性生长，因为它有能力抑制分泌蛋白酶的产生并增加蛋白酶抑制剂的产生。
