title: Insulin-like growth factor II in two human colon-carcinoma cell lines: gene structure and expression, and protein secretion.
abstract: 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.
authors.affiliation: Laboratory of Molecular Oncology, University of Liege, Sart Tilman, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Lambert
authors.forename: A
authors.initials: A
authors.lastname: Carlisi
authors.forename: J
authors.initials: J
authors.lastname: Collette
authors.forename: P
authors.initials: P
authors.lastname: Franchimont
authors.forename: R
authors.initials: R
authors.lastname: Gol-Winkler
mesh_terms: D002277:Carcinoma / Q000737:chemistry*; D002460:Cell Line; D003110:Colonic Neoplasms / Q000737:chemistry*; D003470:Culture Media; D015870:Gene Expression; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D014407:Tumor Cells, Cultured
chemical_list: D003470:Culture Media; D012333:RNA, Messenger; D007335:Insulin-Like Growth Factor II