Insulin-like growth factor-binding protein-2 inhibits proliferation of human embryonic kidney fibroblasts and of ICF-responsive colon carcinoma cell lines
Insulin-like growth factor-binding protein-2 inhibits proliferation of human embryonic kidney fibroblasts and of ICF-responsive colon carcinoma cell lines
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DOI：
10.1016/s0014-5793(98)01011-4
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发表时间：
1998-09-04
期刊：
影响因子：
3.5
通讯作者：
Wolf, E
中科院分区：
文献类型：
--
作者：
Höflich, A;Lahm, H;Wolf, E
到目前为止，胰岛素样生长因子结合蛋白-2(IGFBP-2)的生理作用尚未被直接证实。因此，我们用含有CMV启动子和小鼠IGFBP-2全长基因的表达载体，将含有CMV启动子和小鼠IGFBP-2全长基因的表达载体导入293细胞，用Western Ligand和Western免疫印迹法检测条件培养液中IGFBP-2的分泌，并用特异性放射免疫分析法检测细胞增殖情况。与阴性克隆或未转染亲本293细胞相比，分泌IGFBP-2的克隆对四唑蓝的转化率降低(P<；0.01)。在IGFBP-2分泌克隆中测量到的较低的生长活性在很大程度上被外源IGF-I或-II所补偿。分泌IGFBP-2克隆的条件培养液对IGF反应性结肠癌细胞株(LS513、MT-29)的生长有抑制作用，而阴性克隆的条件培养液则无此作用。此外，来自高水平表达IGFBP-2的克隆的条件培养液抑制了LS513和MT-29细胞的锚定非依赖性生长。相比之下，IGF不敏感的肿瘤细胞系(Co-115)的生长不受条件培养液的影响。我们假设IGFBP-2可能隔离IGF，从而阻止它们传递有丝分裂信号。(C)1998年欧洲生化学会联合会。
So far, the physiological role of insulin-like growth factor binding protein-2 (IGFBP-2) has not been demonstrated directly. Therefore, we transfected 293 cells with an expression vector containing the CMV promoter and the complete cDNA of mouse IGFBP-2, Secretion of bioactive IGFBP-2 into conditioned medium was demonstrated by Western ligand and Western immunoblotting and quantified by specific RIA, For the analysis of cell proliferation three clones exhibiting either high or low/no IGFBP-2 expression were selected and compared to non-transfected parental 293 cells. IGFBP-2 secreting clones displayed reduced conversion of thiazolyl blue when compared to negative clones or non-transfected parental 293 cells (P < 0.01). The lower growth activity measured in the IGFBP-2 secreting clones was compensated in great part by the administration of exogenous IGF-I or -II. Conditioned media of IGFBP-2 secreting clones inhibited growth of IGF-responsive colon tumor cell lines (LS513, MT-29) while those of negative clones did not. In addition, conditioned medium from a clone expressing high levels of IGFBP-2 inhibited anchorage-independent growth of LS513 and MT-29 cells. In contrast, growth of an IGF-unresponsive tumor cell line (Co-115) was not affected by the conditioned media. We hypothesize that IGFBP-2 might sequester the IGFs and thus prevent them from transferring their mitogenic signals. (C) 1998 Federation of European Biochemical Societies.