Butyrate, an essential factor for colonocytes and regulator in the development of
colon cancer, is partially absorbed by the gut. It influences the proliferation and differentiation of several cell types including osteoblasts. We evaluated the effects of different doses of
butyrate on differentiation and functionality of
osteosarcoma cells in vitro and the expression of a pro-inflammatory phenotype in a normal or inflammatory environment. SaOS-2
osteosarcoma cells were induced to differentiate and contemporarily treated for 24 h, 48 h, or 7 days with
sodium butyrate 10-4, 5 × 10-4, or 10-3 M in the presence or absence of
tumor necrosis factor alpha (TNFα) 1 ng/mL, a pro-inflammatory stimulus. Despite the mild effects on proliferation and
alkaline phosphatase activity,
butyrate dose- and time-dependently induced the expression of a differentiated phenotype (RUNX2, COL1A1 gene expression, and
osteopontin gene and
protein expression). This was associated with a partial inhibition of
nuclear factor kappa B (NF-κB) activation and the induction of
histone deacetylase 1 expression. The net effect was the expression of an anti-inflammatory phenotype and the increase in the
osteoprotegerin-to-
receptor activator of nuclear factor kappa-B ligand (RANKL) ratio. Moreover,
butyrate, especially at the highest dose, counteracted the effects of the pro-inflammatory stimulus of TNFα 1 ng/mL.
Butyrate affects
osteosarcoma cell metabolism by anticipating the expression of a differentiated phenotype and by inducing the expression of anti-inflammatory mediators.