Insulin‐like growth factor‐binding protein‐2 inhibits proliferation of human embryonic kidney fibroblasts and of IGF‐responsive colon carcinoma cell lines

FEBS Letters

Höflich, Andreas¹  Wolf, Eckhard¹  Kolb, Helmut²  Blum, Werner³  Lahm, Harald¹ 

[1] Lehrstuhl für Molekulare Tierzucht und Haustiergenetik/Genzentrum, Ludwig-Maximilians-Universität, Feodor-Lynen-Straße 25, 81377 Munich, Germany;Institut für Klinische Chemie, Städtisches Krankenhaus München-Harlaching, 81545 Munich, Germany;Lilly Germany, 61350 Bad Homburg, Germany

关键词: Insulin-like growth factor binding protein-2;    293 cell;    Colon carcinoma cell;    Cell proliferation;    Growth inhibition;   

DOI  :  10.1016/S0014-5793(98)01011-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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, HT-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 HT-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.

【 授权许可】

Unknown