Insulin-like growth factors (IGFs) reduce IGF-binding protein-4 (IGFBP-4) concentration and stimulate IGFBP-3 independently of IGF receptors in human fibroblasts and epidermal cells.
Insulin-like growth factors (IGFs) reduce IGF-binding protein-4 (IGFBP-4) concentration and stimulate IGFBP-3 independently of IGF receptors in human fibroblasts and epidermal cells.
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DOI：
10.1210/endo.130.2.1370799
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发表时间：
1992-02
期刊：
影响因子：
4.8
通讯作者：
E. K. Neely;R. G. Rosenfeld
中科院分区：
文献类型：
--
作者：
E. K. Neely;R. G. Rosenfeld
最近的研究已经提供了一个共识，即胰岛素样生长因子-I（IGF-I）刺激胰岛素样生长因子结合蛋白-3（IGFBP-3）在体内和体外。虽然IGFBP-1与胰岛素浓度呈负相关似乎也已确立，但关于其他IGFBP调节的证据尚不确定。使用免疫沉淀和Western配体印迹，我们已经表征了IGFBPs释放到条件培养基（CM）的细胞从成人成纤维细胞系N3652和人表皮鳞状细胞癌细胞系SCL-1。N3652细胞表达IGFBP-3、IGFBP-2、推测为IGFBP-4的24千道尔顿（kDa）IGFBP以及30和28 kDa的IGFBP。SCL-1表达IGFBP-3和推定的IGFBP-4，在34和30 kDa处具有中间条带。如通过将肽添加至无血清培养基后72小时汇合细胞的CM的配体印迹所确定的，IGF-I和IGF-II在两种细胞系中均有力地刺激IGFBP-3，但在其他方面，两种细胞中的IGFBP调节发散。在N3652细胞中，在IGF-I和IGF-II（100 ng/ml; n = 5次实验）存在下，CM中的IGFBP-3浓度分别增加至基础水平的700%和800%。IGFBP-3不受高达10微克/毫升的胰岛素的影响。与此相反，IGFBP-4水平分别降低54%和73%的100 ng/ml的IGF-I和IGF-II，与胰岛素没有反应。在SCL-1细胞中，IGF-I和IGF-II在刺激IGFBP-3平均增加200%方面几乎相同（n = 5次实验）。胰岛素的效力较低，但可显著刺激IGFBP-3水平。IGF-I、IGF-II和胰岛素均刺激IGFBP-4浓度增加约50%。为了检验IGF诱导的IGFBP-3和IGFBP-4浓度变化通过1型IGF受体调节的假设，我们试图用1型IGF受体抗体α IR-3阻断IGFBP变化，并用对1型受体亲和力很小的IGF-II类似物[Leu 27]IGF-II诱导IGFBP变化。α IR-3未能阻止每个细胞系中IGF诱导的IGFBP-3升高或N3652 CM中IGFBP-4的下降。[Leu 27]IGF-II在诱导IGFBP-3和IGFBP-4浓度变化方面与IGF-II或IGF-I一样有效。（400字处截断摘要）
Recent studies have provided a consensus that insulin-like growth factor-I (IGF-I) stimulates IGF-binding protein-3 (IGFBP-3) in vivo and in vitro. While it also appears well established that IGFBP-1 is inversely related to insulin concentrations, evidence regarding regulation of other IGFBP is inconclusive. Using immunoprecipitation and Western ligand blot, we have characterized the IGFBPs released into conditioned medium (CM) by cells from the adult human fibroblast cell line N3652 and the human epidermal squamous cell carcinoma line SCL-1. N3652 cells expressed IGFBP-3, IGFBP-2, a 24-kilodalton (kDa) IGFBP presumed to be IGFBP-4, and IGFBPs at 30 and 28 kDa. SCL-1 expressed IGFBP-3 and a putative IGFBP-4, with intermediate bands at 34 and 30 kDa. As determined by ligand blot of CM from confluent cells 72 h after the addition of peptides to serum-free medium, IGF-I and IGF-II potently stimulated IGFBP-3 in both cell lines, but otherwise IGFBP regulation in the two cells diverged. In N3652 cells, IGFBP-3 concentrations in CM increased to 700% and 800% of basal levels in the presence of IGF-I and IGF-II (at 100 ng/ml; n = 5 experiments), respectively. IGFBP-3 was not affected by insulin up to 10 micrograms/ml. In contrast, IGFBP-4 levels were diminished 54% and 73% by 100 ng/ml IGF-I and IGF-II, respectively, with no response to insulin. In SCL-1 cells, IGF-I and IGF-II were virtually identical in stimulating a mean 200% increase in IGFBP-3 (n = 5 experiments). Insulin was less potent, but caused a significant stimulation of IGFBP-3 levels. IGF-I, IGF-II, and insulin all stimulated an approximately 50% increase in IGFBP-4 concentrations. To test the hypothesis that IGF-induced alterations in IGFBP-3 and IGFBP-4 concentrations were regulated via the type 1 IGF receptor, we attempted to block IGFBP changes with type 1 IGF receptor antibody alpha IR-3 and to induce IGFBP changes with an IGF-II analog, [Leu27]IGF-II, with little affinity for the type 1 receptor. alpha IR-3 failed to block either the IGF-induced rise in IGFBP-3 in each cell line or the decline in IGFBP-4 in N3652 CM. [Leu27]IGF-II was as potent as IGF-II or IGF-I in inducing changes in IGFBP-3 and IGFBP-4 concentrations.(ABSTRACT TRUNCATED AT 400 WORDS)