Insulin-like growth factor-binding protein-2 inhibits proliferation of human embryonic kidney fibroblasts and of IGF-responsive colon carcinoma cell lines.
FEBS Lett
; 434(3): 329-34, 1998 Sep 04.
Article
em En
| MEDLINE
| ID: mdl-9742949
ABSTRACT
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.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Somatomedinas
/
Neoplasias do Colo
/
Proteína 2 de Ligação a Fator de Crescimento Semelhante à Insulina
/
Rim
Limite:
Animals
/
Humans
Idioma:
En
Revista:
FEBS Lett
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Alemanha