title: Recombinant insulin-like growth factor-I (IGF-I) production in Super-CHO results in the expression of IGF-I receptor and IGF binding protein 3.
abstract: Previously, we described the genetic construction Super- CHO, a cell line capable of autocrine growth under fully defined protein-free conditions. Super-CHO cells constitutively express insulin growth factor-I (IGF-I) and transferrin in sufficient amounts to support long-term, stable growth without the addition of exogenous growth factors, thus making it an ideal host for the production of recombinant biopharmaceuticals. although IGF-I has been successfully expressed in Chinese Hamster Ovary (CHO) cells, the long term effects of recombinant IGF-I expression have not been explored. In particular, the expression of the endogenous IGF-I receptor in response to IGF-I production has not been reported. We report here the transcriptional induction of the type I IGF receptor gene in Super-CHO. In addition, we examined the conditioned medium for the presence of IGF-I binding proteins. Ligand blot analysis reveals the presence of IGF binding proteins present in the medium conditioned by Super-CHO cells as well as CHO cells incubated in the presence of IGF-I. Furthermore, immunoaffinity reveals that Super-CHO expresses IGF binding protein-3 in response to IGF-I production. These results suggest the autocrine growth of Super-CHO involves a complex interaction of cell type specific factors which regulate its utility of IGF-I.
authors.affiliation: Department of Biotechnology, University of New South Wales, Kensington, NSW, 2052, Australia., n.sunstrom@unsw.edu.au.
authors.forename: N A
authors.initials: NA
authors.lastname: Sunstrom
authors.forename: M
authors.initials: M
authors.lastname: Baig
authors.forename: L
authors.initials: L
authors.lastname: Cheng
authors.forename: D
authors.initials: D
authors.lastname: Payet Sugyiono
authors.forename: P
authors.initials: P
authors.lastname: Gray