The regulation of type-I collagen synthesis by insulin-like growth factor-I in human osteoblast-like SaOS-2 cells

Abstract

The effect of insulin-like growth factor-I on collagen synthesis was studied using cultured human osteoblast-like SaOS-2 cells by measuring the incorporation of tritiated L-proline into immunoprecipitable type-I collagen. Tritiated L-proline incorporation into collagen was significantly stimulated by insulin-like growth factor-I in a time- and concentration-dependent manner. Unlabelled L-proline and alpha-(methylamino) isobutyric acid inhibited either the influx into cells, or the incorporation into collagen, of tritiated L-proline. The increase in incorporation of tritiated L-proline was significantly reduced by cycloheximide and actinomycin D. L-Proline incorporation into collagen was also stimulated by insulin-like growth factor-II, insulin-like growth factor-I analogues and insulin. The insulin-like growth factor-I-stimulated L-proline incorporation was inhibited by one of its binding proteins, insulin-like growth factor binding protein-4, in a concentration-dependent manner.

High xylosyltransferase activity in children and during mineralization of osteoblast-like SAOS-2 cells

“…No significant differences in cell numbers were observed. Data are shown as mean±SD and asterisks indicate a significant increase compared to the untreated control (p<0.05) cellular response to HGH [17] and IGF-I [18]. Therefore, we used SAOS-2 cells to study whether the XT expression in osteoblasts is also triggered by HGH and IGF-I.…”

“…SAOS-2 cells have been shown to be responsive to HGH and IGF-I [17,18]. Therefore, we investigated whether addition of HGH or IGF-I results in an upregulation of ALP, XT-I and XT-II.…”

Effects of Placental Extract on Cell Proliferation, Type I Collagen Production, and ALP Secretion in Human Osteosarcoma Cell Line Saos-2

“…Including insulin-like growth factor-1, a key regulator of fetal development, are synthesized in placenta 20) . Type I collagen synthesis in Saos-2 cells is reportedly upregulated by insulin-like growth factor-1 10) . Moreover, Saos-2 cells respond to ext racellular calciu m 2 1) , hormones 1 2) , microRNAs 22) , and growth factors 10) .…”

“…Type I collagen synthesis in Saos-2 cells is reportedly upregulated by insulin-like growth factor-1 10) . Moreover, Saos-2 cells respond to ext racellular calciu m 2 1) , hormones 1 2) , microRNAs 22) , and growth factors 10) . These results support that the multiple molecules in P-placenta synergistically, rather than solely, promote type I collagen production and ALP secretion.…”

“…Alkaline phosphatase (ALP) secreted from osteoblasts degrades inorganic pyrophosphate to phosphate, which is associated with the mineralization of bone 9) . Therefore, type I collagen and ALP are important indicators of bone metabolism 10,11) . However, little information is available regarding the effect of placenta on the cellular metabolism of osteoblasts.…”