The Expression of Insulin-like Growth Factor (IGF), IGF- Binding Protein (IGFBP) and the Role of IGFBP-3 in the Korean Gastric Cancer Cell Lines / 대한암학회지

ABSTRACT

PURPOSE: Insulin-like growth factor (IGF)-I and II are potent mitogens, postulated to exert autocrine and paracrine effects on growth regulation in human gastric cancer. In this study, we evaluated the expression of IGF-I, -II and IGFBPs in a panel of human gastric cancer cell lines. We also evaluated whether high expression of IGFBP-3 in human gastric cancer cells may increase the sensitivity to the anti-proliferative agents. MATERIALS AND METHODS: 10 human korean gastric cancer ceIl lines and 1 Caucacian gastric adenocarcinoma cell line were used for this study. IGF and IGFBP expressions were evaluated by RT-PCR. IGFBP proteins in conditioned media were detected by Western Ligand Blot. Cell survival after treatment of anti-proliferative agents was assessed by MTT assay. RESULTS: IGF-I and II were expressed in all gastric cancer cell lines. In addition, IGF-I and II stimulated the proliferation of gastric cancer cells. The expression of IGFBP-2 was found in all gastric cancer cell lines. IGFBP-4 was expressed in the most of cell lines. IGFBP-3, -4 and -6 were expressed in about 50% of cell lines. The growth inhibition of IGFBP-3 expressing cells by anti- proliferative agents was more significant than that of IGFBP-3 nonexpressing cells. Cell growth inhibition with treatment of these agents was accompanied by increased IGFBP-3 mRNA level. CONCLUSION: These data confirm that IGF-I, -II, and certain IGFBPs were expressed in gastric cancer cells, and gastric cancer cells show the differential growth inhibition by anti-proliferative agents. The differential growth inhibitory effect of anti-proliferative agents is, at least in part, mediated through up-regulation of IGFBP-3 expression.