Role of insulin-like growth factors in autocrine growth of human retinoblastoma Y79 cells
Role of insulin-like growth factors in autocrine growth of human retinoblastoma Y79 cells
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DOI：
10.1111/j.1432-1033.1996.00523.x
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发表时间：
1996-03-01
期刊：
影响因子：
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通讯作者：
Tesoriere, G
中科院分区：
文献类型：
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作者：
Giuliano, M;Vento, R;Tesoriere, G
在这项研究中，我们已经证明，人视网膜母细胞瘤Y 79细胞产生胰岛素样生长因子（IGFs）I型和II型，并将它们释放到培养基中。我们还确定，通过竞争性研究和交联程序，Y 79细胞含有I型IGF受体（IGF-IR）。胰岛素、IGF-I和IGF-II均能下调IGF-IR的表达，其作用具有浓度和时间依赖性。Scatchard分析表明，与胰岛素孵育显着降低了IGF-I的结合能力，而IGF-I结合计算的表观Kd值没有显着修改。IGF-I、IGF-II和胰岛素诱导IGF-IR的酪氨酸磷酸化。然而，即使在无血清培养基中培养的细胞中，在不添加任何外源性生长因子的情况下，该受体的酪氨酸磷酸化信号也不太强。关于胰岛素受体底物-1（IRS 1）的酪氨酸磷酸化也发现了类似的结果。IGF-IR和IRS 1的酪氨酸磷酸化，无论是在基础条件下还是在生长因子刺激后，当加入IGF-IR的单克隆抗体α-IR 3时，都被强烈抑制。IGF-I能够诱导Y 79细胞增殖，其作用完全被α-IR 3抑制。该抗体还显著降低了在不添加刺激因子的无血清培养基中培养的Y 79细胞的增殖。我们的研究结果表明，IGF-I和IGF-IR介导的自分泌生长机制在Y 79细胞。
In this study, we have demonstrated that human retinoblastoma Y79 cells produce insulin-like growth factors (IGFs) type I and type Il and release them into the medium. We have also ascertained, by means of competitive studies and cross-linking procedure, that Y79 cells contain the type-I IGF receptor (IGF-IR). Furthermore, surface-bound IGF-I is internalised by the receptor, then degraded to amino acids.Insulin, IGF-I and IGF-II caused down-regulation of IGF-IR; the effect is concentration and time dependant. Scatchard analysis demonstrated that incubation with insulin markedly decreased the binding capacity measured for IGF-I while the apparent K-d value calculated for IGF-I binding was not significantly modified. IGF-I, IGF-II and insulin induced tyrosine phosphorylation of IGF-IR. Tyrosine phosphorylation of this receptor with, however, a less strong signal, was detectable even in cells cultured in serum-free medium without the addition of any exogenous growth factor. Similar results have been found concerning the tyrosine phosphorylation of insulin receptor substrate-1 (IRS 1). Tyrosine phosphorylation of both IGF-IR and IRS 1, either under basal conditions or after stimulation with growth factors, was strongly inhibited when alpha-IR3, a monoclonal antibody to IGF-IR, was added to the culture.IGF-I was capable of inducing Y79 cell proliferation and its effect was entirely inhibited by the addition of alpha-IR3. This antibody also markedly reduced the proliferation of Y79 cells cultured in serum-free medium not supplemented with stimulatory factors. Our results indicate that IGF-I and IGF-IR mediate an autocrine growth mechanism in Y79 cells.