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- Title
Insulin-Like Growth Factor-I and Epidermal Growth Factor Regulate Insulin-Like Growth Factor Binding Protein-3 (IGFBP-3) in the Human Keratinocyte Cell Line HaCaT.
- Authors
Wraight, Christopher J.; Werther, George A.
- Abstract
The human keratinocyte cell line HaCaT has a basal phenotype and secretes an insulin-like growth factor (IGF) binding protein, IGFBP-3, which modulates its IGF-I response. Keratinocytes are highly responsive to mitogenic stimulation by IGF-I and epidermal growth factor (EGF), but the effect of these growth factors on IGFBP secretion by keratinocytes is not known. We investigated the effects of IGF-I and EGF, as well as three other skin-growth regulators, retinoic acid, basic fibroblast growth factor, and dexamethasone, on mitogenic stimulation and IGFBP-3 production in HaCaT cells. IGF-I and EGF were strongly mitogenic, whereas retinoic acid, basic fibroblast growth factor, and dexamethasone were not significantly mitogenic. IGF-I increased the level of IGFBP-3 in cell-conditioned medium by up to two-fold, whereas EGF caused a twenty-fold reduction in IGFBP-3. Retinoic acid and basic fibroblast growth factor had only minor effects on IGFBP-3 and dexamethasone had no effect. IGF-I stimulation of IGFBP-3 did not involve increases in IGFBP-3 mRNA; however, EGF, consistent with its effect on IGFBP-3 protein, caused a fivefold reduction in IGFBP-3 mRNA. In summary, EGF profoundly inhibited IGFBP-3 synthesis in basal keratinocytes, whereas IGF-I increased IGFBP-3 levels by a post-transcriptional mechanism. We hypothesize that by inhibiting IGFBP-3 production in basal keratinocytes, epidermal mitogens such as EGF might stimulate epidermal growth indirectly by increasing local IGF-I availability.
- Subjects
KERATINOCYTES; CELL lines; INSULIN-like growth factor-binding proteins; FIBROBLAST growth factors; MITOGENS; CONNECTIVE tissue cells
- Publication
Journal of Investigative Dermatology, 1995, Vol 105, Issue 4, p602
- ISSN
0022-202X
- Publication type
Article
- DOI
10.1111/1523-1747.ep12323716