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Insulin‐like growth factor II in two human colon‐carcinoma cell lines: Gene structure and expression, and protein secretion
Author(s) -
Lambert Sylvie,
Carlisi Agnes,
Collette Julien,
Franchimont Paul,
GolWinkler Rosita
Publication year - 1992
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.2910520313
Subject(s) - insulin like growth factor 2 , cell culture , radioimmunoassay , growth factor , gene expression , biology , microbiology and biotechnology , messenger rna , gene , secretion , endocrinology , medicine , biochemistry , receptor , genetics
Abnormal expression and structural modification of the IGF‐II gene in correlation with high IGF‐II production have recently been described in human colorectal tumors in comparison with normal adjacent tissues. Here, we have studied IGF‐II in 2 human colon‐carcinoma cell lines, HT29 and COLO 320DM. RFLP analyses revealed no apparent alteration at the IGF‐II locus in these 2 cell lines. HT29 cells weakly expressed IGF‐II mRNA in comparison with the high over‐expression previously observed in some colorectal tumors, and only the 4.8‐kb mRNA species was present. In addition, the serum‐free medium conditioned by HT29 cells contained high IGF‐II levels (approx. 900 ng/ 10 8 cells), as measured in a specific IGF‐II radioimmunoassay (RIA). After chromatography on Bio‐Gel P‐60, we observed that 64% of the total IGF‐II secreted by HT29 cells were present as a high‐molecular‐weight form of about 17 kDa. In contrast, no detectable expression of the IGF‐II gene was observed in COLO 320DM cells, and low IGF‐II levels were secreted by these cells in the serum‐free medium, with only 9% total IGF‐II represented by the large species. © 1992 Wiley‐Liss, Inc.