z-logo
Premium
Type‐II insulin‐like growth‐factor receptor in conditioned medium from HT‐29 human colon carcinoma cell line
Author(s) -
Garrouste Françoise,
RemacleBonnet Maryse,
Culouscou Jean M.,
Marvaldi Jacques,
Pommier Gilbert
Publication year - 1991
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910470523
Subject(s) - insulin like growth factor 2 , receptor , insulin like growth factor receptor , insulin like growth factor 2 receptor , cell culture , growth factor , biology , extracellular , endocrinology , mannose 6 phosphate , fetal bovine serum , insulin like growth factor , medicine , biochemistry , chemistry , microbiology and biotechnology , insulin like growth factor 1 receptor , cell , genetics
The HT‐29 human colon cancer cell line has previously been shown to secrete high amounts of insulin‐like growth factor II (IGF‐II). The recent demonstration that soluble IGF‐II/ mannose 6‐phosphate receptor was present in fetal serum prompted us to search for a release of type‐II IGF receptor by these human colonic carcinoma cells. Serum‐free conditioned medium from the HT‐29 cell line was gel filtered on Sephadex G‐200. There was significant binding of [ 125 I]IGF‐II to the void volume fractions in addition to binding to the 40‐kDa IGF‐binding protein (IGF‐BP) fractions. Competitive binding studies using [ l25 I]IGF‐II and the void volume pool showed a pattern typical of the type‐II receptor. It exhibited a high affinity for IGF‐II (K D = 0.4 nM), but had a low affinity for IGF‐I (K D = 6.8 nM), and no detectable affinity for insulin. Additional evidence was provided by affinity cross‐linking of [ l25 I]IGF‐II to the same high‐molecular‐weight material which demonstrated a major specific band at 250kDa after reduction of disulfide bonds. In contrast, the type‐I IGF receptor was undetectable. The extracellular type‐II IGF receptor was not a significant carrier for IGF‐II since virtually all IGF‐II secreted by HT‐29 cells was associated with IGF‐BP. The presence of a soluble IGF‐II/mannose 6‐phosphate receptor in the culture medium from colonic cancer cells suggests that it may play an important role in tumor pathogenesis.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here