Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) Induces the Osteoblastic Differentiation of the Human Osteosarcoma Cell Line SaOS-2

Abstract

The Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) is a hematopoietic growth factor that regulates the in vitro and in vivo proliferation and differentiation of hematopoietic cells through the interaction with a specific heterodimeric receptor complex (GM-CSFR), consisting of an alpha and a beta chain with molecular weights of 80 and 120 KDa, respectively. We have studied the expression of the GM-CSFR (alpha chain) on the surface of the human osteosarcoma cell line SaOS-2 and the in vitro effects of different concentrations (10, 100, and 200 ng/ml) of GM-CSF on GM-CSFR expression and the biological activity of SaOS-2 cells. Our data show that SaOS-2 cells express GM-CSFR and that GM-CSF can down-regulate the expression of its own receptor on these cells. Furthermore, to evaluate the biological effects of GM-CSF on SaOS-2 cells, we have investigated cell proliferation and differentiation of these cells treated with different doses of the growth factor through: (1) a morphological analysis of typical osteoblast differentiation markers such as osteopontin and BSP-II; (2) measurement of alkaline phosphatase (ALP) activity; (3) production of bone ECM components (collagen I, fibronectin, tenascin, and laminin); (4) production of interleukin-6 (IL-6) and osteocalcin in the culture medium. The results show that the in vitro treatment of SaOS-2 cells with recombinant human GM-CSF causes a decreased cell proliferation and an increased production of osteopontin, BSP-II, ALP, IL-6, and most but not all ECM components. These findings suggest that GM-CSF can regulate proliferation and differentiation of osteoblast-like SaOS-2 cells and could also play an unexpected role in the maturation of bone tissue.

Osteogenic BMPs promote tumor growth of human osteosarcomas that harbor differentiation defects

“…First, OS cells exhibit the characteristics of undifferentiated osteoblasts. 3,[33][34][35][36][37][38][39] Second, we demonstrated that differentiationpromoting agents (eg, PPARg agonists and 9-cis retinoic acid) can induce OS differentiation and inhibit OS proliferation. 3,40 Third, a recent study that showed Runx2 and p27 KIP1 -mediated osteoblast terminal differentiation is disrupted in OS.…”

Sandblasted-acid-etched titanium surface influences in vitro the biologicalbehavior of SaOS-2 human osteoblast-like cells

“…SaOS-2 cells represent a good in vitro model to study the interaction of cells with implant biomaterials exhibiting large analogies with immature osteoblast cells [38][39][40][41]47) compared to other immortalized cell lines. Shapira and Halabi 43) recently reported that, in contrast to primary cultured human osteoblasts that do not yield consistent results due to their tendency to lose the osteoblastic phenotype during cell culture, SaOS-2 cells showed more manageability without loss of phenotypical expression.…”

“…Several primary and transformed cell lines have been used to develop culture systems to study the interaction of cells with implant biomaterials 8,14,[17][18][19][36][37][38][39][40][41][42][43][44][45][46] . SaOS-2 is an osteoblast-like cell line, derived from a human osteosarcoma, that several studies have demonstrated to be a relevant cell model, due to its large analogies with immature osteoblast cells [38][39][40][41]47) and better manageability when compared to primary human cell Sandblasted-acid-etched titanium surface influences in vitro the biological behavior of SaOS-2 human osteoblast-like cells culture 43) .…”

“…SaOS-2 is an osteoblast-like cell line, derived from a human osteosarcoma, that several studies have demonstrated to be a relevant cell model, due to its large analogies with immature osteoblast cells [38][39][40][41]47) and better manageability when compared to primary human cell Sandblasted-acid-etched titanium surface influences in vitro the biological behavior of SaOS-2 human osteoblast-like cells culture 43) . The aim of the present study was to evaluate in vitro the biological behavior of SaOS-2 cells, cultured on two different titanium surfaces, smooth (S) and sandblastedacid-etched (SBA), by investigating cell morphology, adhesion, proliferation, expression of some bone differentiation markers and ECM components as well as the expression of specific integrin subunits.…”

THE EFFECT OF SURFACE PORE SIZE ON THE DIFFERENTIATION OF RAT BONE MARROW CELLS: MORPHOLOGICAL OBSERVATIONS AND EXPRESSION OF BONE RELATED PROTEIN mRNA

“…Shiigai et al 30) reported that an extracellular matrix (ECM), which is more than 100 nm wide and contains fibronectin and integrin, might be created between the wall of an MF and an L-929 fibroblast. Several studies have suggested that differentiation toward a differentiated osteoblast correlates with an increase in alkaline phosphatase activity 9) , bone related protein and ECM production 18,24) . Owen et al 23) reported that type 1 collagen, fibronectin, vitronectin and tenascin are among the components of the ECM produced by differentiated osteoblasts, and Postiglione et al 25) demonstrated that the ECM was easily produced, depending on the type of surface.…”